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  • 51.
    Kang, Evan S. H.
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Shiran Chaharsoughi, Mina
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rossi, Stefano
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hybrid plasmonic metasurfaces2019In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 126, no 14, article id 140901Article in journal (Refereed)
    Abstract [en]

    Plasmonic metasurfaces based on ensembles of distributed metallic nanostructures can absorb, scatter, and in other ways shape light at the nanoscale. Forming hybrid plasmonic metasurfaces by combination with other materials opens up for new research directions and novel applications. This perspective highlights some of the recent advancements in this vibrant research field. Particular emphasis is put on hybrid plasmonic metasurfaces comprising organic materials and on concepts related to switchable surfaces, light-to-heat conversion, and hybridized light-matter states based on strong coupling.

  • 52.
    Kang, Minji
    et al.
    Korea Inst Sci and Technol, South Korea.
    Cha, An-Na
    Korea Inst Sci and Technol, South Korea.
    Lee, Sang-A
    Korea Inst Sci and Technol, South Korea.
    Lee, Seoung-Ki
    Korea Inst Sci and Technol, South Korea.
    Bae, Sukang
    Korea Inst Sci and Technol, South Korea.
    Jeon, Dae-Young
    Korea Inst Sci and Technol, South Korea.
    Hong, Jae-Min
    Korea Inst Sci and Technol, South Korea.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kim, Tae-Wook
    Jeonbuk Natl Univ, South Korea.
    Light-sensitive charge storage medium with spironaphthooxazine molecule-polymer blends for dual-functional organic phototransistor memory2020In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 78, article id UNSP 105554Article in journal (Refereed)
    Abstract [en]

    Organic phototransistor memory is considered as a promising optoelectronic device owing to its multifunctionality. However, due to the poor reliability of each function and the complexity of the device structure, it is necessary to optimize the thin-film process of functional materials when constructing multiple functions into a single device. Here, we demonstrate a dual-functional device that is both a working memory transistor and a phototransistor by incorporating photochromic spironaphthooxazine molecules into an organic insulating layer. The photochmmic molecules in the polymer matrix not only exhibit nonvolatile charge storage properties similar to nano-floating gates but also feature a reversible electronic band structure upon alternating irradiation with ultraviolet and visible light, which makes the device function as both an electrical memory transistor and a phototransistor. Furthermore, the photoresponsive charge trap layer in the demonstrated device leads to excellent memory performance under both dark and light conditions, which includes a large memory window (-56 V), stable endurance cycles (amp;gt;10(2)), and good retention characteristics (amp;gt;10(4) s). Our findings suggest an alternative strategy to realize organic multifunctional nonvolatile memories.

  • 53.
    Karami Rad, Meysam
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rezania, Alireza
    Aalborg Univ, Denmark.
    Omid, Mahmoud
    Univ Tehran, Iran.
    Rajabipour, Ali
    Univ Tehran, Iran.
    Rosendahl, Lasse
    Aalborg Univ, Denmark.
    Study on material properties effect for maximization of thermoelectric power generation2019In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 138, p. 236-242Article in journal (Refereed)
    Abstract [en]

    Thermoelectric generators (TEGs) have mostly been used in niche applications due to the low efficiency. This study aims to evaluate the effect of different material transport properties such as Seebeck coefficient, thermal conductivity, and electrical resistivity, on the system-level performance of the TEGs. A mathematical model was developed in MATLAB and verified by the experimental data to evaluate various thermoelectric (TE) materials with unit figure of merit (ZT=1) and with a diverse combination of properties. The results shows increment in the power factor with a factor of 15, which corresponds an enhancement in the thermal conductivity by factor of 13.33 for fixed Zr, can increase the power output up to 45%. The results moreover shows, higher power factor has more impact on the power generation at lower fill factors (FFs) and smaller thermal resistance of the heat sink and heat source. (C) 2019 Elsevier Ltd. All rights reserved.

  • 54.
    Khan, Ziyauddin
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Can Hybrid Na-Air Batteries Outperform Nonaqueous Na-O-2 Batteries?2020In: ADVANCED SCIENCE, ISSN 2198-3844, article id 1902866Article in journal (Refereed)
    Abstract [en]

    In recent years, there has been an upsurge in the study of novel and alternative energy storage devices beyond lithium-based systems due to the exponential increase in price of lithium. Sodium (Na) metal-based batteries can be a possible alternative to lithium-based batteries due to the similar electrochemical voltage of Na and Li together with the thousand times higher natural abundance of Na compared to Li. Though two different kinds of Na-O-2 batteries have been studied specifically based on electrolytes until now, very recently, a hybrid Na-air cell has shown distinctive advantage over nonaqueous cell systems. Hybrid Na-air batteries provide a fundamental advantage due to the formation of highly soluble discharge product (sodium hydroxide) which leads to low overpotentials for charge and discharge processes, high electrical energy efficiency, and good cyclic stability. Herein, the current status and challenges associated with hybrid Na-air batteries are reported. Also, a brief description of nonaqueous Na-O-2 batteries and its close competition with hybrid Na-air batteries are provided.

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  • 55.
    Kim, Donghyun
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Why Is Pristine PEDOT Oxidized to 33%? A Density Functional Theory Study of Oxidative Polymerization Mechanism2019In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 123, no 24, p. 5160-5167Article in journal (Refereed)
    Abstract [en]

    Currently, a theoretical understanding of thermodynamics and kinetics of the oxidative polymerization of poly(3,4-ethylenedioxythiophene) (best known as PEDOT) is missing. In the present study, step-by-step density functional theory calculations of the radical polymerization of PEDOT with tosylate counterions (PEDOT:TOS) using Fe3+(TOS-)(3) as oxidant and dopant are performed. We calculate the Gibbs free energy for the conventional mechanism that consists of the polymerization of neutral PEDOT oligomers first, followed by their oxidation (doping). We also propose an alternative mechanism of polymerization, in which the already oxidized oligomers are used as reactants, leading to doped (oxidized) oligomers as products during polymerization. Our calculations indicate that the alternative mechanism is more efficient for longer PEDOT oligomers (chain length N amp;gt; 6). We find that the oxidation of the EDOT monomer is the rate-limiting step for both mechanisms. Another focus of our study is the understanding of the maximum oxidation level that can be achieved during polymerization. Our calculations provide a theoretical explanation of "the magic number" of 33% for the oxidation level typically reported for the pristine (i.e., as-polymerized) materials and relate it to the change of the character of the bonds in the oligomers (aromatic to quinoid) that occurs at this oxidation level.

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  • 56.
    Kim, Nara
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Lienemann, Samuel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mengistie, Desalegn
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Calif Polytech State Univ San Luis Obispo, CA 93407 USA.
    Kee, Seyoung
    Univ Auckland, New Zealand.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Biophysics and bioengineering. Linköping University, Faculty of Science & Engineering.
    Gueskine, Viktor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Leclere, Philippe
    Univ Mons, Belgium.
    Lazzaroni, Roberto
    Univ Mons, Belgium.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Elastic conducting polymer composites in thermoelectric modules2020In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 11, no 1Article in journal (Refereed)
    Abstract [en]

    The rapid growth of wearables has created a demand for lightweight, elastic and conformal energy harvesting and storage devices. The conducting polymer poly(3,4-ethylenedioxythiophene) has shown great promise for thermoelectric generators, however, the thick layers of pristine poly(3,4-ethylenedioxythiophene) required for effective energy harvesting are too hard and brittle for seamless integration into wearables. Poly(3,4-ethylenedioxythiophene)-elastomer composites have been developed to improve its mechanical properties, although so far without simultaneously achieving softness, high electrical conductivity, and stretchability. Here we report an aqueously processed poly(3,4-ethylenedioxythiophene)-polyurethane-ionic liquid composite, which combines high conductivity (>140Scm(-1)) with superior stretchability (>600%), elasticity, and low Youngs modulus (<7MPa). The outstanding performance of this organic nanocomposite is the result of favorable percolation networks on the nano- and micro-scale and the plasticizing effect of the ionic liquid. The elastic thermoelectric material is implemented in the first reported intrinsically stretchable organic thermoelectric module. Though deformable thermoelectric materials are desirable for integrating thermoelectric devices into wearable electronics, typical thermoelectric materials are too brittle for practical application. Here, the authors report a high-performance elastic composite for stretchable thermoelectric modules.

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  • 57.
    Kim, Nara
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Petsagkourakis, Ioannis
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Chen, Shangzhi
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Electric Transport Properties in PEDOT Thin Films2019In: Conjugated Polymers: Properties, Processing, and Applications / [ed] John R. Reynolds; Barry C. Thompson; Terje A. Skotheim, Boca Raton: CRC Press, 2019, p. 45-128Chapter in book (Refereed)
    Abstract [en]

    In this chapter, the authors summarize their understanding of Poly(3,4-ethylenedioxythiophene) (PEDOT), with respect to its chemical and physical fundamentals. They focus upon the structure of several PEDOT systems, from the angstrom level and up, and the impact on both electronic and ionic transport. The authors discuss the structural properties of PEDOT:X and PEDOT:poly(styrenesulfonate) based on experimental data probed at the scale ranging from angstrom to submicrometer. The morphology of PEDOT is influenced by the nature of counter-ions, especially at high oxidation levels. The doping anions intercalate between PEDOT chains to form a “sandwich” structure to screen the positive charges in PEDOT chains. The authors provide the main transport coefficients such as electrical conductivity s, Seebeck coefficient S, and Peltier coefficient σ, starting from a general thermodynamic consideration. The optical conductivity of PEDOT has also been examined based on the effective medium approximation, which is normally used to describe microscopic permittivity properties of composites made from several different constituents.

  • 58.
    Kottravel, Sathish
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. SeRC, Sweden.
    Falk, Martin
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. SeRC, Sweden.
    Masood, Talha Bin
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. SeRC, Sweden.
    Linares, Mathieu
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. SeRC, Sweden.
    Hotz, Ingrid
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. SeRC, Sweden.
    Visual Analysis of Charge Flow Networks for Complex Morphologies2019In: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 38, no 3, p. 479-489Article in journal (Refereed)
    Abstract [en]

    In the field of organic electronics, understanding complex material morphologies and their role in efficient charge transport in solar cells is extremely important. Related processes are studied using the Ising model and Kinetic Monte Carlo simulations resulting in large ensembles of stochastic trajectories. Naive visualization of these trajectories, individually or as a whole, does not lead to new knowledge discovery through exploration. In this paper, we present novel visualization and exploration methods to analyze this complex dynamic data, which provide succinct and meaningful abstractions leading to scientific insights. We propose a morphology abstraction yielding a network composed of material pockets and the interfaces, which serves as backbone for the visualization of the charge diffusion. The trajectory network is created using a novel way of implicitly attracting the trajectories to the skeleton of the morphology relying on a relaxation process. Each individual trajectory is then represented as a connected sequence of nodes in the skeleton. The final network summarizes all of these sequences in a single aggregated network. We apply our method to three different morphologies and demonstrate its suitability for exploring this kind of data.

    The full text will be freely available from 2020-07-10 10:51
  • 59.
    Lach, Stefan
    et al.
    Univ Kaiserslautern, Germany.
    Altenhof, Anna
    Univ Kaiserslautern, Germany.
    Shi, Shengwei
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. Wuhan Inst Technol, Peoples R China.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ziegler, Christiane
    Univ Kaiserslautern, Germany.
    Electronic and magnetic properties of a ferromagnetic cobalt surface by adsorbing ultrathin films of tetracyanoethylene2019In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 21, no 28, p. 15833-15844Article in journal (Refereed)
    Abstract [en]

    Ultrathin films of tetracyanoethylene (TCNE) on Co(100) were investigated by means of spin-integrated and spin-resolved photoemission spectroscopy ((sp-)UPS), X-ray photoemission spectroscopy (XPS), near edge X-ray absorption fine-structure spectroscopy (NEXAFS), and X-ray magnetic circular dichroism (XMCD). We found a coverage-dependent modulation of the interface dipole and a switching between a metallic and a resistive spin filtering at the interface triggered by two distinct adsorption geometries of TCNE. The strongest hybridization and spin structure modifications are found at low coverage with a face-on adsorption geometry indicating changes in the distance between the surface Co atoms beneath. TCNE has the potential to manipulate the magnetic moments in the Co surface itself, including the possibility of magnetic hardening effects. In summary, the system TCNE/Co offers an experimentally rather easy and controllable way to build up a stable molecular platform stabilizing the reactive ferromagnetic Co surface and customizing the electronic and magnetic properties of the resulting spinterface simultaneously. This makes this system very attractive for spintronic applications as an alternative, less reactive but highly spin polarized foundation beside graphene-based systems.

  • 60.
    Lay, Makara
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Univ Sains Malaysia, Malaysia.
    Thajudin, Nuur Laila Najwa
    Univ Sains Malaysia, Malaysia.
    Hamid, Zuratul Ain Abdul
    Univ Sains Malaysia, Malaysia.
    Rusli, Arjulizan
    Univ Sains Malaysia, Malaysia.
    Abdullah, Muhammad Khalil
    Univ Sains Malaysia, Malaysia.
    Shuib, Raa Khimi
    Univ Sains Malaysia, Malaysia.
    Comparison of physical and mechanical properties of PLA, ABS and nylon 6 fabricated using fused deposition modeling and injection molding2019In: Composites Part B: Engineering, ISSN 1359-8368, E-ISSN 1879-1069, Vol. 176, article id UNSP 107341Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to compare the physical and mechanical performance of poly(lactic acid) (PLA), acrylonitrile butadiene styrene (ABS), and nylon 6 fabricated using fused deposition modeling (FDM) and conventional injection molding. It is found that different processing methods did not affect the viscosity of the samples, and the percentage difference for the density measurement is less than 4%. Water absorption of FDM samples is approximately 108% higher compared to those fabricated using the injection molding. The results also revealed that the FDM method did not strongly affect the degree of crystallinity of ABS, but it increased the degree of crystallinity of PLA and nylon 6. The tensile strength, Youngs modulus, elongation at break, and impact strength of FDM samples were approximately 48%, 50%, 48%, and 78%, lower compared with the injection molded samples. The results presented can provide a guide to manufacturing the final products using FDM with the desired performance.

  • 61.
    Leiqiang, Qin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jiang, Jianxia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Jinan Univ, Peoples R China.
    Tao, Quanzheng
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Wang, Chuan Fei
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Persson, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Persson, Per O A
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hou, Lintao
    Jinan Univ, Peoples R China.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Zhang, Fengling
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering. Jinan Univ, Peoples R China.
    A flexible semitransparent photovoltaic supercapacitor based on water-processed MXene electrodes2020In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 8, no 11, p. 5467-5475Article in journal (Refereed)
    Abstract [en]

    Solar energy, although it has the highest power density available in terms of renewable energy, has the drawback of being erratic. Integrating an energy harvesting and storage device into photovoltaic energy storage modules is a viable route for obtaining self-powered energy systems. Herein, an MXene-based all-solution processed semitransparent flexible photovoltaic supercapacitor (PSC) was fabricated by integrating a flexible organic photovoltaic (OPV) with Ti3C2Tx MXene as the electrode and transparent MXene supercapacitors with an organic ionogel as the electrolyte in the vertical direction, using Ti3C2Tx thin film as a common electrode. In the quest for a semitransparent flexible PSC, Ti3C2Tx MXene was first used as a transparent electrode for OPV with a high power conversion efficiency of 13.6%. The ionogel electrolyte-based transparent MXene supercapacitor shows a high volumetric capacitance of 502 F cm(-3) and excellent stability. Finally, a flexible PSC with a high average transmittance of over 33.5% was successfully constructed by all-solution processing and a remarkable storage efficiency of 88% was achieved. This strategy enables a simple route for fabricating MXene based high-performance all-solution-processed flexible PSCs, which is important for realizing flexible and printable electronics for future technologies.

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  • 62.
    Li, Guowei
    et al.
    Max Planck Inst Chem Phys Solids, Germany.
    Fu, Chenguang
    Max Planck Inst Chem Phys Solids, Germany.
    Shi, Wujun
    ShanghaiTech Univ, Peoples R China.
    Jiao, Lin
    Max Planck Inst Chem Phys Solids, Germany.
    Wu, Jiquan
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Yang, Qun
    Max Planck Inst Chem Phys Solids, Germany.
    Saha, Rana
    Max Planck Inst Microstruct Phys, Germany.
    Kamminga, Machteld E.
    Univ Groningen, Netherlands.
    Srivastava, Abhay K.
    Max Planck Inst Microstruct Phys, Germany.
    Liu, Enke
    Max Planck Inst Chem Phys Solids, Germany.
    Yazdani, Aliza N.
    Carleton Coll, MN 55057 USA.
    Kumar, Nitesh
    Max Planck Inst Chem Phys Solids, Germany.
    Zhang, Jian
    Tech Univ Dresden, Germany.
    Blake, Graeme R.
    Univ Groningen, Netherlands.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wirth, Steffen
    Max Planck Inst Chem Phys Solids, Germany.
    Auffermann, Gudrun
    Max Planck Inst Chem Phys Solids, Germany.
    Gooth, Johannes
    Max Planck Inst Chem Phys Solids, Germany.
    Parkin, Stuart
    Max Planck Inst Microstruct Phys, Germany.
    Madhavan, Vidya
    Univ Illinois, IL 61801 USA; Univ Illinois, IL 61801 USA.
    Feng, Xinliang
    Tech Univ Dresden, Germany.
    Sun, Yan
    Max Planck Inst Chem Phys Solids, Germany.
    Felser, Claudia
    Max Planck Inst Chem Phys Solids, Germany.
    Dirac Nodal Arc Semimetal PtSn4: An Ideal Platform for Understanding Surface Properties and Catalysis for Hydrogen EvolutionIn: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773Article in journal (Refereed)
    Abstract [en]

    Conductivity, carrier mobility, and a suitable Gibbs free energy are important criteria that determine the performance of catalysts for a hydrogen evolution reaction (HER). However, it is a challenge to combine these factors into a single compound. Herein, we discover a superior electrocatalyst for a HER in the recently identified Dirac nodal arc semimetal PtSn4. The determined turnover frequency (TOF) for each active site of PtSn4 is 1.54 H-2 s(-1) at 100 mV. This sets a benchmark for HER catalysis on Pt-based noble metals and earth-abundant metal catalysts. We make use of the robust surface states of PtSn4 as their electrons can be transferred to the adsorbed hydrogen atoms in the catalytic process more efficiently. In addition, PtSn4 displays excellent chemical and electrochemical stabilities after long-term exposure in air and long-time HER stability tests.

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  • 63.
    Li, Miao
    et al.
    Tampere Univ, Finland.
    Honkanen, Mari
    Tampere Univ, Finland.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rokaya, Chakra
    Tampere Univ, Finland.
    Schramm, Andreas
    Tampere Univ, Finland.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berger, Paul R.
    Tampere Univ, Finland; Ohio State Univ, OH 43210 USA.
    Lupo, Donald
    Tampere Univ, Finland.
    0.7-GHz Solution-Processed Indium Oxide Rectifying Diodes2020In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 67, no 1, p. 360-364Article in journal (Refereed)
    Abstract [en]

    Solution-based deposition, with its simplicity and possibility for upscaling through printing, is a promising process for low-cost electronics. Metal oxide semiconductor devices, especially indium oxide with its excellent electrical properties, offer high performance compared to amorphous Si-based rivals, and with a form factor conducive to flexible and wearable electronics. Here, rectifying diodes based on an amorphous spin-coated indium oxide are fabricated for high-speed applications. We report a solution-processed diode approaching the UHF range, based on indium oxide, with aluminum and gold as the electrodes. The device was spin-coated from a precursor material and configured into a half-wave rectifier. The J-V and frequency behavior of the diodes were studied, and the material composition of the diode was investigated by X-ray photoemission spectroscopy (XPS). The 3-dB point was found to be over 700 MHz. The results are promising for the development of autonomously powered wireless Internet-of-Things systems based on scalable, low-cost processes.

  • 64.
    Liu, Xianjie
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Electronic Structure Characterization of Soft Semiconductors2019In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 6, no 16, article id 1900439Article in journal (Refereed)
    Abstract [en]

    Soft semiconductors are a class of materials that have seen increased interest in terms of both basic research and development of technology, in particular optoelectronic devices. These materials, organic semiconductors and metal halide perovskites, are defined by being more mechanically malleable than the traditional crystalline inorganic semiconductors and with thin film fabrication done at lower temperatures and often from solution. In this short perspective article, basic properties of the materials are introduced, as well as their typical applications and a number of advanced characterization techniques that offer distinct advantages for studying soft semiconductor thin films.

  • 65.
    Malekian, Bita
    et al.
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Xiong, Kunli
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Kang, Evan S. H.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, John
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Emilsson, Gustav
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Rommel, Marcus
    Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden.
    Sannomiya, Takumi
    Department of Materials Science and Engineering, 4259 Nagatsuta Midoriku, Yokohama, Japan.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Dahlin, Andreas
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Optical Properties of Plasmonic Nanopore Arrays Prepared by Electron Beam and Colloidal Lithography2019In: Nanoscale Advances, E-ISSN 2516-0230, Vol. 1, no 11, p. 4282-4289Article in journal (Refereed)
    Abstract [en]

    Solid state nanopores are central structures for many applications. To date, much effort has been spent on controlled fabrication of single nanopores, while relatively little work has focused on large scale fabrication of arrays of nanopores. In this work we show wafer-scale fabrication of plasmonic nanopores in 50 nm thick silicon nitride membranes with one or two 30 nm gold films, using electron beam lithography with a negative resist or a new version of colloidal lithography. Both approaches offer good control of pore diameter (even below 100 nm) and with high yield (>90%) of intact membranes. Colloidal lithography has the advantage of parallel patterning without expensive equipment. Despite its serial nature, electron beam lithography provides high throughput and can make arbitrary array patterns. Importantly, both methods prevent metal from ending up on the membrane pore sidewalls. The new fabrication methods make it possible to compare the optical properties of structurally identical plasmonic nanopore arrays with either long-range order (e-beam) or short-range order (colloidal). The resonance features in the extinction spectrum are very similar for both structures when the pitch is the same as the characteristic spacing in the self-assembled colloidal pattern. Long-range ordering slightly enhances the magnitude of the extinction maximum and blueshift the transmission maximum by tens of nm. Upon reducing the diameter in long-range ordered arrays, the resonance is reduced in magnitude and the transmission maximum is further blue shifted, just like for short-range ordered arrays. These effects are well explained by interpreting the spectra as Fano interference between the grating-type excitation of propagating surface plasmons and the broad transmission via individual pores in the metal film. Furthermore, we find that only the short-range ordered arrays scatter light, which we attribute to the highly limited effective period in the short-range ordered system and the corresponding lack of coherent suppression of scattering via interference effects.

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  • 66.
    Mehandzhiyski, Alexandar
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rolland, Nicolas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. KTH Royal Inst Technol, Sweden.
    Garg, Mohit
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wohlert, Jakob
    KTH Royal Inst Technol, Sweden.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    A novel supra coarse-grained model for celluloseIn: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882XArticle in journal (Refereed)
    Abstract [en]

    Cellulose being the most widely available biopolymer on Earth is attracting significant interest from the industry and research communities. While molecular simulations can be used to understand fundamental aspects of cellulose nanocrystal self-assembly, a model that can perform on the experimental scale is currently missing. In our study we develop a supra coarse-grained (sCG) model of cellulose nanocrystal which aims to bridge the gap between molecular simulations and experiments. The sCG model is based on atomistic molecular dynamics simulations and it is developed with the force-matching coarse-graining procedure. The validity of the model is shown through comparison with experimental and simulation results of the elastic modulus, self-diffusion coefficients and cellulose fiber twisting angle. We also present two representative case studies, self-assembly of nanocrystal during solvent evaporation and simulation of a chiral nematic phase ordering. Finally, we discuss possible future applications for our model. Graphic abstract

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  • 67.
    Miglbauer, Eva
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gryszel, Maciej
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Warsaw Univ Technol, Poland.
    Photochemical evolution of hydrogen peroxide on lignins2020In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 22, no 3, p. 673-677Article in journal (Refereed)
    Abstract [en]

    Means of sustainable on-demand hydrogen peroxide production are sought after for numerous industrial, agricultural, and environmental applications. Herein we present the capacity of lignin and lignin sulfonate to behave as photocatalysts that upon irradiation reduce oxygen to hydrogen peroxide. Water-soluble lignin sulfonate acts as a homogeneous photocatalyst in solution, while lignin in thin-film form behaves as a heterogenous photocatalyst. In both cases, the photochemical cycle is closed via the oxidation of electron donors in solution, a process which competes with the autooxidation of lignin. Therefore, lignins can be destructively photooxidized to produce hydrogen peroxide as well as photochemically oxidizing low-oxidation potential species. These findings enable new photochemistry applications with abundant biopolymers and inform the growing body of knowledge on photochemical evolution of hydrogen peroxide.

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  • 68.
    Mitraka, Evangelia
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gryszel, Maciej
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jafari, Mohammad Javad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Singh, Amritpal
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Warczak, Magdalena
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mitrakas, Manassis
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Electrocatalytic Production of Hydrogen Peroxide with Poly(3,4-ethylenedioxythiophene) Electrodes2019In: Advanced Sustainable Systems, ISSN 2366-7486, Vol. 3, no 2, p. 1-6, article id 1800110Article in journal (Refereed)
    Abstract [en]

    Electrocatalysis for energy‐efficient chemical transformations is a central concept behind sustainable technologies. Numerous efforts focus on synthesizing hydrogen peroxide, a major industrial chemical and potential fuel, using simple and green methods. Electrochemical synthesis of peroxide is a promising route. Herein it is demonstrated that the conducting polymer poly(3,4‐ethylenedioxythiophene), PEDOT, is an efficient and selective heterogeneous catalyst for the direct reduction of oxygen to hydrogen peroxide. While many metallic catalysts are known to generate peroxide, they subsequently catalyze decomposition of peroxide to water. PEDOT electrodes can support continuous generation of high concentrations of peroxide with Faraday efficiency remaining close to 100%. The mechanisms of PEDOT‐catalyzed reduction of O2 to H2O2 using in situ spectroscopic techniques and theoretical calculations, which both corroborate the existence of a chemisorbed reactive intermediate on the polymer chains that kinetically favors the selective reduction reaction to H2O2, are explored. These results offer a viable method for peroxide electrosynthesis and open new possibilities for intrinsic catalytic properties of conducting polymers.

  • 69.
    Mitraka, Evangelia
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Sjoestedt, Anna
    RISE Bioecon, Sweden.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hakansson, Karl M. O.
    RISE Bioecon, Sweden.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    PEDOT-Cellulose Gas Diffusion Electrodes for Disposable Fuel CellsIn: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, article id 1900097Article in journal (Refereed)
    Abstract [en]

    The mass implementation of renewable energy sources is limited by the lack of energy storage solutions operating on various timescales. Electrochemical technologies such as supercapacitors and batteries cannot handle long storage time because of self-discharge issues. The combination of fuel storage technology and fuel cells is an attractive solution for long storage times. In that context, large-scale fuel cell solutions are required for massive energy storage in cities, which leads to possible concepts such as low-cost disposable fully organic membrane assemblies in fuel cells to avoid regeneration of expensive poisoned electrodes. Here, the formation of an organic gas diffusion electrode (GDE) fabricated by paper-making production, combined with in situ polymerization is demonstrated for the first time. Cellulose is used as a 3D scaffold functionalized with poly(3,4-ethylenedioxythiophene) (PEDOT) serving as both an electrical conductor and an electrocatalyst of high efficiency for the oxygen reduction reaction. The PEDOT-cellulose porous GDE is implemented in a membrane assembly and demonstrated in a H-2-O-2 fuel cell. The demonstration of low-cost material/manufacturing that is environmentally friendly is a paradigm shift in the development of fuel cells for a sustainable society.

  • 70.
    Méhes, Gábor
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mulla, Yusuf
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Granberg, Hjalmar
    Res Inst Sweden, Sweden.
    Che, Canyan
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Res Inst Sweden, Sweden.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Stavrinidou, Eleni
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Solar Heat-Enhanced Energy Conversion in Devices Based on Photosynthetic Membranes and PEDOT:PSS-Nanocellulose Electrodes2020In: ADVANCED SUSTAINABLE SYSTEMS, ISSN 2366-7486, article id 1900100Article in journal (Refereed)
    Abstract [en]

    Energy harvesting from photosynthetic membranes, proteins, or bacteria through bio-photovoltaic or bio-electrochemical approaches has been proposed as a new route to clean energy. A major shortcoming of these and solar cell technologies is the underutilization of solar irradiation wavelengths in the IR region, especially those in the far IR region. Here, a biohybrid energy-harvesting device is demonstrated that exploits IR radiation, via convection and thermoelectric effects, to improve the resulting energy conversion performance. A composite of nanocellulose and the conducting polymer system poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is used as the anode in biohybrid cells that includes thylakoid membranes (TMs) and redox mediators (RMs) in solution. By irradiating the conducting polymer electrode by an IR light-emitting diode, a sixfold enhancement in the harvested bio-photovoltaic power is achieved, without compromising stability of operation. Investigation of the output currents reveals that IR irradiation generates convective heat transfer in the electrolyte bulk, which enhances the redox reactions of RMs at the anode by suppressing diffusion limitations. In addition, a fast-transient thermoelectric component, originating from the PEDOT:PSS-nanocellulose-electrolyte interphase, further increases the bio-photocurrent. These results pave the way for the development of energy-harvesting biohybrids that make use of heat, via IR absorption, to enhance energy conversion efficiency.

  • 71.
    Oladiran Bamgbopa, Musbadeen
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Edberg, Jesper
    RISE Acreo, Sweden.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Understanding the characteristics of conducting polymer-redox biopolymer supercapacitors2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 41, p. 23973-23980Article in journal (Refereed)
    Abstract [en]

    The growth of renewable energy production has sparked a huge demand for cheap and large-scale electrical storage solutions. Organic supercapacitors and batteries are envisioned as one, among several, candidates for this task due to the great abundance of their constituent materials. In particular, the class of supercapacitors based on conjugated polymer-redox biopolymer composites are of great interest, since they combine the benefit of high electrical conductivity of the conducting polymers with the low cost and high specific capacitance of redox biopolymers. The optimization of such complex systems is a grand challenge and until now there have been a lack of models available to ease that task. Here, we present a novel model that combines the charge transport and impedance properties of conducting polymers with the electrochemical characteristics of redox polymers. The model reproduces a wide range of experimental data and elucidates the coupling of several critical processes within these supercapacitors, such as the double-layer capacitance, redox kinetics and dissolution/release of the redox polymer to the electrolyte. Further, the model also predicts the dependencies of the power and energy densities on the electrode composition. The developed model shows how organic supercapacitors can be analyzed beyond archetypical equivalent circuit models and thus constitutes a promising tool for further advancements and optimization within the field of research of green energy storage technology.

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  • 72.
    Oliveras-Gonzalez, Cristina
    et al.
    Univ Angers, France.
    Linares, Mathieu
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Swedish e-Science Research Centre (SeRC), Sweden.
    Amabilino, David B.
    Univ Nottingham, England.
    Avarvari, Narcis
    Univ Angers, France.
    Large Synthetic Molecule that either Folds or Aggregates through Weak Supramolecular Interactions Determined by Solvent2019In: ACS OMEGA, ISSN 2470-1343, Vol. 4, no 6, p. 10108-10120Article in journal (Refereed)
    Abstract [en]

    Weak noncovalent interactions between large disclike molecules in poorly solvating media generally lead to the formation of fibers where the molecules stack atop one another. Here, we show that a particular chiral spacing group between large aromatic moieties, which usually lead to columnar stacks, in this case gives rise to an intramolecularly folded structure in relatively polar solvents, but in very apolar solvents forms finite aggregates. The molecule that displays this behavior has a C-3 symmetric benzene-1,3,5-tris(3,3-diamido-2,2-bipyridine) (BTAB) core with three metalloporphyrin units appended to it through short chiral spacers. Quite well-defined chromophore arrangements are evident by circular dichroism (CD) spectroscopy of this compound in solution, where clear exciton coupled bands of porphyrins are observed. In more polar solvents where the molecules are dispersed, a relatively weak CD signal is observed as a result of intramolecular folding, a feature confirmed by molecular modeling. The intramolecular folding was confirmed by measuring the CD of a C-2 symmetric analogue. The C-3 symmetric BTAB cores that would normally be expected to stack in a chiral arrangement in apolar solvents show no indication of CD, suggesting that there is no transfer of chirality through it (although the expected planar conformation of the 2,2-bipyridine unit is confirmed by NMR spectroscopy). The incorporation of the porphyrins on the 3,3-diamino-2,2-bipyridine moiety spaced by a chiral unit leaves the latter incapable of assembling through supramolecular pi-pi stacking. Rather, modeling indicates that the three metalloporphyrin units interact, thanks to van der Waals interactions, favoring their close interactions over that of the BTAB units. Atomic force microscopy shows that, in contrast to other examples of molecules with the same core, disclike aggregates (rather than fibrillar one dimensional aggregates) are favored by the C-3 symmetric molecule. The closed structures are formed through nondirectional interlocking of porphyrin rings. The chiral spacer between the rigid core and the porphyrin moieties is undoubtedly important in determining the outcome in polar or less polar solvents, as modeling shows that this joint in the molecule has two favored conformations that render the molecule relatively flat or convex.

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  • 73.
    Paulsen, B.D.
    et al.
    Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Stavrinidou, Eleni
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Rivnay, J.
    Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States; Simpson Querrey Institute, Northwestern University, Chicago, IL, United States.
    Organic mixed ionic–electronic conductors2019In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660Article, review/survey (Refereed)
    Abstract [en]

    Materials that efficiently transport and couple ionic and electronic charge are key to advancing a host of technological developments for next-generation bioelectronic, optoelectronic and energy storage devices. Here we highlight key progress in the design and study of organic mixed ionic–electronic conductors (OMIECs), a diverse family of soft synthetically tunable mixed conductors. Across applications, the same interrelated fundamental physical processes dictate OMIEC properties and determine device performance. Owing to ionic and electronic interactions and coupled transport properties, OMIECs demand special understanding beyond knowledge derived from the study of organic thin films and membranes meant to support either electronic or ionic processes only. We address seemingly conflicting views and terminology regarding charging processes in these materials, and highlight recent approaches that extend fundamental understanding and contribute to the advancement of materials. Further progress is predicated on multimodal and multi-scale approaches to overcome lingering barriers to OMIEC design and implementation.

  • 74.
    Petsagkourakis, Ioannis
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kim, Nara
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Poly(3,4-ethylenedioxythiophene): Chemical Synthesis, Transport Properties, and Thermoelectric Devices2019In: ADVANCED ELECTRONIC MATERIALS, ISSN 2199-160X, Vol. 5, no 11Article, review/survey (Refereed)
    Abstract [en]

    Since their discovery in the seventies, conducting polymers have been chemically designed to acquire specific optical and electrical properties for various applications. Poly(3,4-ethylenedioxythiophene) (PEDOT) is among the most successful polymers as indicated by approximate to 12 000 articles mentioning it to date. PEDOT is found as transparent polymer electrodes in solar cells and light-emitting diodes, as printed electrodes in transistors, and as the main component of electrochromic displays, supercapacitors, and electrochemical transistors. For around seven years, PEDOT has been classified as the first thermoelectric polymer that converts heat flow into electricity. This has triggered a renewed interest in the scientific community, with about 400 publications including the keyword "PEDOT" and "thermoelectric." Among the topics covered by those scientific works are: i) the optimization of the thermoelectric properties, ii) understanding of the interplay between electrical properties and morphology, iii) the origin of the Seebeck coefficient, iv) the characterization of its thermal conductivity; and v) the design of thermoelectric devices. This work aims to be a pedagogical introduction to PEDOT but also to review the state-of-the art of its thermoelectric properties and thermoelectric devices. Hopefully, this work will inspire scientists to find chemical design rules to bring organic thermoelectrics beyond PEDOT.

  • 75.
    Poxson, David
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Erik
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Bonisoli, Alberto
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Ist Italiano Tecnol, Italy; St Anna Sch Adv Studies, Italy.
    Linderhed, Ulrika
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Res Inst Sweden, Sweden.
    Abrahamsson, Tobias
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Matthiesen, Isabelle
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. KTH Royal Inst Technol, Sweden.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Capillary-Fiber Based Electrophoretic Delivery Device2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 15, p. 14200-14207Article in journal (Refereed)
    Abstract [en]

    Organic electronic ion pumps (OEIPs) are versatile tools for electrophoretic delivery of substances with high spatiotemporal resolution. To date, OEIPs and similar iontronic components have been fabricated using thin-film techniques and often rely on laborious, multistep photolithographic processes. OEIPs have been demonstrated in a variety of in vitro and in vivo settings for controlling biological systems, but the thin-film form factor and limited repertoire of polyelectrolyte materials and device fabrication techniques unnecessarily constrain the possibilities for miniaturization and extremely localized substance delivery, e.g., the greater range of pharmaceutical compounds, on the scale of a single cell. Here, we demonstrate an entirely new OEIP form factor based on capillary fibers that include hyperbranched polyglycerols (dPGs) as the selective electrophoretic membrane. The dPGs enable electrophoretic channels with a high concentration of fixed charges and well-controlled cross-linking and can be realized using a simple one-pot fluidic manufacturing protocol. Selective electrophoretic transport of cations and anions of various sizes is demonstrated, including large substances that are difficult to transport with other OEIP technologies. We present a method for tailoring and characterizing the electrophoretic channels fixed charge concentration in the operational state. Subsequently, we compare the experimental performance of these capillary OEIPs to a computational model and explain unexpected features in the ionic current for the transport and delivery of larger, lower-mobility ionic compounds. From this model, we are able to elucidate several operational and design principles relevant to miniaturized electrophoretic drug delivery technologies in general. Overall, the compactness of the capillary OEIP enables electrophoretic delivery devices with probelike geometries, suitable for a variety of ionic compounds, paving the way for less-invasive implantation into biological systems and for healthcare applications.

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  • 76.
    Rehmen, Junaiz
    et al.
    Univ South Australia, Australia.
    Zuber, Kamil
    Univ South Australia, Australia.
    Modarresi, Mohsen
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Ferdowsi Univ Mashhad, Iran.
    Kim, Donghyun
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Charrault, Eric
    Univ South Australia, Australia.
    Jannasch, Patric
    Lund Univ, Sweden.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Evans, Drew
    Univ South Australia, Australia.
    Karlsson, Christoffer
    Lund Univ, Sweden.
    Structural Control of Charge Storage Capacity to Achieve 100% Doping in Vapor Phase-Polymerized PEDOT/Tosylate2019In: ACS OMEGA, ISSN 2470-1343, Vol. 4, no 26, p. 21818-21826Article in journal (Refereed)
    Abstract [en]

    Vapor phase polymerization (VPP) is used to fabricate a series of tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes on carbon paper. The series of VPP PEDOT/tosylate coatings has varying levels of crystallinity and electrical conductivity because of the use (or not) of nonionic triblock copolymers in the oxidant solution during synthesis. As a result, the impact of the structure on charge storage capacity is investigated using tetra-n-butylammonium hexafluorophosphate (0.1 M in acetonitrile). The ability to insert anions, and hence store charge, of the VPP PEDOT/tosylate is inversely related to its electrical conductivity. In the case of no nonionic triblock copolymer employed, the VPP PEDOT/tosylate achieves electrochemical doping levels of 1.0 charge per monomer or greater (amp;gt;= 100% doping level). Such high doping levels are demonstrated to be plausible by molecular dynamics simulations and density functional theory calculations. Experiments show that this high doping level is attainable when the PEDOT structure is weakly crystalline with (relatively) large crystallite domains.

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  • 77.
    Riera-Galindo, Sergi
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Leonardi, Francesca
    Inst Ciencia Mat Barcelona ICMAB CSIC, Spain.
    Pfattner, Raphael
    Inst Ciencia Mat Barcelona ICMAB CSIC, Spain.
    Mas-Torrent, Marta
    Inst Ciencia Mat Barcelona ICMAB CSIC, Spain.
    Organic Semiconductor/Polymer Blend Films for Organic Field-Effect Transistors2019In: ADVANCED MATERIALS TECHNOLOGIES, ISSN 2365-709X, Vol. 4, no 9, article id 1900104Article, review/survey (Refereed)
    Abstract [en]

    The development of low-cost printed organic electronics entails the processing of active organic semiconductors (OSCs) through solution-based techniques. However, the preparation of large-area uniform and reproducible films based on OSC inks can be very challenging due to the low viscosity of their solutions, which causes dewetting problems, the low stability of OSC polymer solutions, or the difficulty in achieving appropriate crystal order. To circumvent this, a promising route is the use of blends of OSCs and insulating binding polymers. This approach typically gives rise to films with an enhanced crystallinity and organic field-effect transistors (OFETs) with significantly improved device performance. Recent progress in the fabrication of OFETs based on OSC/binding polymer inks is reviewed, highlighting the main morphological and structural features that play a major role in determining the final electrical properties and some future perspectives. Undoubtedly, the use of these types of blends results in more reliable and reproducible devices that can be fabricated on large areas and at low cost and, thus, this methodology brings great expectations for the implementation of OSCs in real-world applications.

  • 78.
    Riera-Galindo, Sergi
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Orbelli Biroli, Alessio
    CNR, Italy.
    Forni, Alessandra
    CNR, Italy.
    Puttisong, Yuttapoom
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tessore, Francesca
    Univ Milan, Italy.
    Pizzotti, Maddalena
    Univ Milan, Italy.
    Pavlopoulou, Eleni
    Univ Bordeaux, France.
    Solano, Eduardo
    ALBA Synchrotron Light Source, Spain.
    Wang, Suhao
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Gang
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ruoko, Tero-Petri
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    di Carlo, Gabriele
    Univ Milan, Italy.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Impact of Singly Occupied Molecular Orbital Energy on the n-Doping Efficiency of Benzimidazole Derivatives2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 41, p. 37981-37990Article in journal (Refereed)
    Abstract [en]

    We investigated the impact of singly occupied molecular orbital (SOMO) energy on the n-doping efficiency of benzimidazole derivatives. By designing and synthesizing a series of new air-stable benzimidazole-based dopants with different SOMO energy levels, we demonstrated that an increase of the dopant SOMO energy by only similar to 0.3 eV enhances the electrical conductivity of a benchmark electron-transporting naphthalenediimide-bithiophene polymer by more than 1 order of magnitude. By combining electrical, X-ray diffraction, and electron paramagnetic resonance measurements with density functional theory calculations and analytical transport simulations, we quantitatively characterized the conductivity, Seebeck coefficient, spin density, and crystallinity of the doped polymer as a function of the dopant SOMO energy. Our findings strongly indicate that charge and energy transport are dominated by the (relative) position of the SOMO level, whereas morphological differences appear to play a lesser role. These results set molecular-design guidelines for next-generation n-type dopants.

    The full text will be freely available from 2020-09-20 12:58
  • 79.
    Rolland, Nicolas
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Royal Inst Technol KTH, Sweden.
    Franco-Gonzalez, Juan Felipe
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Can Mobility Negative Temperature Coefficient Be Reconciled with the Hopping Character of Transport in Conducting Polymers?2019In: ACS APPLIED POLYMER MATERIALS, ISSN 2637-6105, Vol. 1, no 11, p. 2833-2839Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene) (PEDOT) is a conducting polymer that is used in a wide range of applications such as electronics, optoelectronics, and bio-electronics, where the fundamental understanding of the charge transport, and in particular of the electrical conductivity sigma, is a prerequisite to develop new high performance devices. There are many reports in the literature where the conductivity of archetypical conducting polymer PEDOT doped with tosylate (PEDOT:TOS) exhibits a dry negative temperature coefficient, d sigma/dT amp;lt; 0, which is strikingly different from the activated-type behavior with d sigma/dT amp;gt; 0 commonly observed in most conducting polymers. This unusual temperature dependence was attributed to the transition from the photon-assisted hopping to the metallic behavior, which is however difficult to rationalize taking into account that this transition occurs at high temperatures. In order to understand the origin of this unusual behavior, multiscale mobility calculations in PEDOT:TOS for the model of hopping transport were performed, where changes in the morphology and the density of states (DOS) with the temperature were explicitly taken into account. The morphology was calculated using the Molecular Dynamics simulations, and the hopping rates between the chains were calculated quantum-mechanically following the Miller-Abrahams formalism. Our results reproduce the observed negative temperature coefficient, where however the percolation analysis shows that this behavior mainly arises because of the changes in morphology upon heating when the system becomes less ordered. This results in a less efficient pi-pi stacking and hence lower mobility in the system. We therefore conclude that experimentally observed negative mobility temperature coefficient in conducting polymers at high temperatures is consistent with the hopping transport, and does not necessarily reflect the transition to a metallic band-like transport. Based on our multiscale modeling, we introduce a simple Gaussian Disorder Model for the efficient mobility calculations, where the DOS broadening is a function of the temperature, and where the transfer integral distribution is a bimodal distribution evolving with temperature.

    The full text will be freely available from 2020-10-08 12:52
  • 80.
    Ruoko, Tero-Petri
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Chemistry and Advanced Materials, Laboratory of Chemistry and Bioengineering,Tampere University of Technology, Tampere, Finland..
    Hiltunen, Arto
    Tampere Univ Technol, Finland.
    Iivonen, Tomi
    Univ Helsinki, Finland.
    Ulkuniemi, Riina
    Tampere Univ Technol, Finland.
    Lahtonen, Kimmo
    Tampere Univ Technol, Finland.
    Ali-Loeytty, Harri
    Tampere Univ Technol, Finland.
    Mizohata, Kenichiro
    Univ Helsinki, Finland.
    Valden, Mika
    Tampere Univ Technol, Finland.
    Leskelae, Markku
    Univ Helsinki, Finland.
    Tkachenko, Nikolai V.
    Tampere Univ Technol, Finland.
    Charge carrier dynamics in tantalum oxide overlayered and tantalum doped hematite photoanodes2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 7, p. 3206-3215Article in journal (Refereed)
    Abstract [en]

    We employ atomic layer deposition to prepare 50 nm thick hematite photoanodes followed by passivating them with a 0.5 nm thick Ta2O5-overlayer and compare them with samples uniformly doped with the same amount of tantalum. We observe a three-fold improvement in photocurrent with the same onset voltage using Ta-overlayer hematite photoanodes, while electrochemical impedance spectroscopy under visible light irradiation shows a decreased amount of surface states under water splitting conditions. The Tadoped samples have an even higher increase in photocurrent along with a 0.15 V cathodic shift in the onset voltage and decreased resistivity. However, the surface state capacitance for the Ta-doped sample is twice that of the reference photoanode, which implies a larger amount of surface hole accumulation. We further utilize transient absorption spectroscopy in the sub-millisecond to second timescale under operating conditions to show that electron trapping in both Ta2O5-passivated and Ta-doped samples is markedly reduced. Ultrafast transient absorption spectroscopy in the sub-picosecond to nanosecond timescale shows faster charge carrier dynamics and reduced recombination in the Ta-doped hematite photoanode resulting in the increased photoelectrochemical performance when compared with the Ta2O5-overlayer sample. Our results show that passivation does not affect the poor charge carrier dynamics intrinsic to hematite based photoanodes. The Ta-doping strategy results in more efficient electron extraction, solving the electron trapping issue and leading to increased performance over the surface passivation strategy.

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  • 81.
    Sahalianov, Ihor
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Radchenko, Taras M.
    NAS Ukraine, Ukraine.
    Tatarenko, Valentyn A.
    NAS Ukraine, Ukraine.
    Cuniberti, Gianaurelio
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany; Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Prylutskyy, Yuriy I
    Taras Shevchenko Natl Univ Kyiv, Ukraine.
    Straintronics in graphene: Extra large electronic band gap induced by tensile and shear strains2019In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 126, no 5, article id 054302Article in journal (Refereed)
    Abstract [en]

    The possibility of inducing a sizeable energy gap in the electronic structure of a graphene layer is still one of the biggest and most debated challenges in graphene electronics. Despite promising theoretical results, some experimental studies report the absence of a bandgap even in highly mechanically strained graphene. In this paper, we address the main reasons for these discrepancies and study the influence of uniaxial tensile and shear strains as well as their combinations on the eventual bandgap opening in monolayer graphene. Deformation-dependent bandgap diagrams are constructed over a wide range of the strain tensor parameters of up to 26%, which is close to predicted graphene breaking point. The use of a combination of shear strain and uniaxial tensile deformations is found to be the easiest way for bandgap opening and tuning. The results of our numerical calculations demonstrate that shear strains can induce a bandgap of up to 4eV at the largest elastic deformations, while a combination of shear and uniaxial strains can provide an energy gap of up to 6eV that is substantially higher than for some materials (including silicon) typically used in nanoelectronic devices. The numerically obtained findings are carefully contrasted with other results available in the literature.

  • 82.
    Sahalianov, Ihor
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Singh, Sandeep Kumar
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    The intrinsic volumetric capacitance of conducting polymers: pseudo-capacitors or double-layer supercapacitors?2019In: RSC ADVANCES, Vol. 9, no 72, p. 42498-42508Article in journal (Refereed)
    Abstract [en]

    The capacitance of conducting polymers represents one of the most important material parameters that in many cases determines the device and material performances. Despite a vast number of experimental studies, the theoretical understanding of the origin of the capacitance in conducting polymers remains unsatisfactory and appears even controversial. Here, we present a theoretical method, based on first principle capacitance calculations using density functional theory (DFT), and apply it to calculate the volumetric capacitance of two archetypical conducting polymers: poly(3,4-ethylene dioxythiophene) (PEDOT) and polypyrrole (PPy). Our aim is to achieve a quantitate description of the volumetric capacitance and to provide a qualitative understanding of its nature at the atomistic level. We find that the volumetric capacitance of PEDOT and PPy is approximate to 100 F cm(-3) and approximate to 300 F cm(-3), respectively, which is within the range of the corresponding reported experimental results. We demonstrate that the capacitance of conducting polymers originates from charges stored in atomistic Stern layers formed by counterions and doped polymeric chains. The Stern layers have a purely electrostatic origin, since the counterions do not form any bonds with the atoms of the polymeric chains, and no charge transfer between the counterions and conducting polymer takes place. This classifies the conducting polymers as double-layer supercapacitors rather than pseudo-capacitors. Further, we analyze contributions to the total capacitance originating from the classical capacitance C-C and the quantum capacitance C-Q, respectively, and find that the latter provides a dominant contribution. The method of calculations of the capacitance developed in the present paper is rather general and opens up the way for engineering and optimizing the capacitive response of the conducting polymers.

  • 83.
    Sardar, Samim
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wojcik, Pawel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kang, Evan
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Shanker, Ravi
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Structural coloration by inkjet-printing of optical microcavities and metasurfaces2019In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 7, no 28, p. 8698-8704Article in journal (Refereed)
    Abstract [en]

    Structural color generation by plasmonic and other means has attracted significant interest as a solution to avoid inks based on dyes. Prominent advantages include better robustness compared with organic dyes while also providing high chromaticity and brightness in ultrathin films. However, lack of cheap and scalable fabrication techniques has so far limited structural coloration to only a few applications and functional devices. Here, we demonstrate reflective (plasmonic) structural coloration at high resolution by inkjet printing on non-patterned surfaces. The method is flexible, scalable to large areas, and avoids complicated or costly fabrication steps. Optical microcavities on flexible plastic substrates were made starting with an inkjet-printed silver film as a bottom mirror. Inkjet-printed organic dielectric micropixels then served as the spacer layer, resulting in optical microcavities with reflective structural colors after coating with a thin semi-transparent metallic top layer. Optimization of ink formulation allowed for uniform pixels with minimum coffee stain effects as well as control of spacer thickness (around 50-150 nm) and color by varying the solid content of the ink. We investigate the possibility to obtain red, green and blue (RGB) pixels and demonstrate the improvement of particularly the blue coloration using wavelength-dependent plasmon absorption of gold nanoislands as a top mirror. Inkjet printing of optical microcavities and plasmonic cavities may find use in various applications, such as reflective displays in color.

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  • 84. Order onlineBuy this publication >>
    Seitanidou, Maria
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Overcoming Limitations of Iontronic Delivery Devices2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic electronic devices are considered as one of the best candidates to replace conventional inorganic electronic devices due to their electronic conductive functionality, low-cost production techniques, the ability to tune their optical and electronic properties using organic chemistry, and their mechanical flexibility. Moreover, these systems are ideal for bioelectronic applications due to their softness, biocompatibility, and most importantly, their electronic and ionic transport. Indeed, these materials are compatible with biological tissues and cells improving the signal transduction between electronic devices and electrically excitable cells. As ions serve as one of the primary signal carriers of cells, they can selectively tune a cell’s activity; therefore, an improved interface between electronics and biological systems can offer several advantages in healthcare, e.g. the development of efficient drug delivery devices.  

    The main focus of this thesis is the development of electronic delivery devices. Electrophoretic delivery devices called organic electronic ion pumps (OEIPs) are used to electronically control the delivery of small ions, neurotransmitters, and drugs with high spatiotemporal resolution. This work elucidates the ion transport processes and phenomena that happen in the ion exchange membranes during ion delivery and clarifies which parameters are crucial for the ion transport efficiency of the OEIPs. This thesis shows a systematic investigation of these parameters and indicates new methods and OEIP designs to overcome these challenges. Two novel OEIP designs are developed and introduced in this thesis to improve the local ion transport while limiting side effects. OEIPs based on palladium proton trap contacts can improve the membrane permselectivity and optimize the delivery of γ-aminobutyric acid (GABA) neurotransmitters at low pH while preventing any undesired pH changes from proton transport in the biological systems. And OEIPs based on glass capillary fibers are developed to overcome the limitations of devices on planar substrates, related to more complex and larger biologically relevant ion delivery with low mobility for implantable applications. This design can optimize the transport of ions and drugs such as salicylic acid (SA) at low concentrations and at relatively much higher rates, thereby addressing a wider range of biomedically relevant applications and needs.   

    List of papers
    1. pH Dependence of γ-Aminobutyric Acid Iontronic Transport
    Open this publication in new window or tab >>pH Dependence of γ-Aminobutyric Acid Iontronic Transport
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    2017 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 121, no 30, p. 7284-7289Article in journal (Refereed) Published
    Abstract [en]

    The organic electronic ion pump (OEIP) has been developed as an “iontronic” tool for delivery of biological signaling compounds. OEIPs rely on electrophoretically “pumping” charged compounds, either at neutral or shifted pH, through an ion-selective channel. Significant shifts in pH lead to an abundance of H+ or OH–, which are delivered along with the intended substance. While this method has been used to transport various neurotransmitters, the role of pH has not been explored. Here we present an investigation of the role of pH on OEIP transport efficiency using the neurotransmitter γ-aminobutyric acid (GABA) as the model cationic delivery substance. GABA transport is evaluated at various pHs using electrical and chemical characterization and compared to molecular dynamics simulations, all of which agree that pH 3 is ideal for GABA transport. These results demonstrate a useful method for optimizing transport of other substances and thus broadening OEIP applications.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2017
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-139731 (URN)10.1021/acs.jpcb.7b05218 (DOI)000407189200007 ()28741949 (PubMedID)2-s2.0-85026913272 (Scopus ID)
    Note

    Funding agencies: EU Seventh Framework Programme [607896]; Knut and Alice Wallenberg Foundation [2012.0302]; Onnesjo Foundation

    Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2020-02-17Bibliographically approved
    2. Overcoming transport limitations in miniaturized electrophoretic delivery devices
    Open this publication in new window or tab >>Overcoming transport limitations in miniaturized electrophoretic delivery devices
    2019 (English)In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 19, no 8, p. 1427-1435Article in journal (Refereed) Published
    Abstract [en]

    Organic electronic ion pumps (OEIPs) have been used for delivery of biological signaling compounds, at high spatiotemporal resolution, to a variety of biological targets. The miniaturization of this technology provides several advantages, ranging from better spatiotemporal control of delivery to reduced invasiveness for implanted OEIPs. One route to miniaturization is to develop OEIPs based on glass capillary fibers that are filled with a polyelectrolyte (cation exchange membrane, CEM). These devices can be easily inserted and brought into close proximity to targeted cells and tissues and could be considered as a starting point for other fiber-based OEIP and iontronic technologies enabling favorable implantable device geometries. While characterizing capillary OEIPs we observed deviations from the typical linear current-voltage behavior. Here we report a systematic investigation of these irregularities by performing experimental characterizations in combination with computational modelling. The cause of the observed irregularities is due to concentration polarization established at the OEIP inlet, which in turn causes electric field-enhanced water dissociation at the inlet. Water dissociation generates protons and is typically problematic for many applications. By adding an ion-selective cap that separates the inlet from the source reservoir this effect is then, to a large extent, suppressed. By increasing the surface area of the inlet with the addition of the cap, the concentration polarization is reduced which thereby allows for significantly higher delivery rates. These results demonstrate a useful approach to optimize transport and delivery of therapeutic substances at low concentrations via miniaturized electrophoretic delivery devices, thus considerably broadening the opportunities for implantable OEIP applications.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2019
    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-157204 (URN)10.1039/c9lc00038k (DOI)000465283700008 ()30875418 (PubMedID)2-s2.0-85064156567 (Scopus ID)
    Note

    Funding Agencies|Swedish Foundation for Strategic Research; Advanced Functional Materials SFO-center at Linkoping University; Onnesjo Foundation; Knut and Alice Wallenberg Foundation

    Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2020-02-17Bibliographically approved
    3. Modulating Inflammation in Monocytes Using Capillary Fiber Organic Electronic Ion Pumps
    Open this publication in new window or tab >>Modulating Inflammation in Monocytes Using Capillary Fiber Organic Electronic Ion Pumps
    Show others...
    2019 (English)In: Advanced Healthcare Materials, ISSN 2192-2640, E-ISSN 2192-2659, Vol. 8, no 19, article id 1900813Article in journal (Refereed) Published
    Abstract [en]

    An organic electronic ion pump (OEIP) delivers ions and drugs from a source, through a charge selective membrane, to a target upon an electric bias. Miniaturization of this technology is crucial and will provide several advantages, ranging from better spatiotemporal control of delivery to reduced invasiveness for implanted OEIPs. To miniaturize OEIPs, new configurations have been developed based on glass capillary fibers filled with an anion exchange membrane (AEM). Fiber capillary OEIPs can be easily implanted in proximity to targeted cells and tissues. Herein, the efficacy of such a fiber capillary OEIP for modulation of inflammation in human monocytes is demonstrated. The devices are located on inflammatory monocytes and local delivery of salicylic acid (SA) is initiated. Highly localized SA delivery results in a significant decrease in cytokine (tumor necrosis factor alpha and interleukin 6) levels after lipopolysaccharide stimulation. The findings-the first use of such capillary OEIPs in mammalian cells or systems-demonstrate the utility of the technology for optimizing transport and delivery of different therapeutic substances at low concentrations, with the benefit of local and controlled administration that limits the adverse effect of oral/systemic drug delivery.

    Place, publisher, year, edition, pages
    WILEY, 2019
    Keywords
    bioelectronics; capillary fibers; cytokines; drug delivery; electrophoresis; inflammation; ion exchange membranes; iontronics; organic electronics
    National Category
    Biophysics
    Identifiers
    urn:nbn:se:liu:diva-161161 (URN)10.1002/adhm.201900813 (DOI)000486128400001 ()31502760 (PubMedID)
    Note

    Funding Agencies|Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research [RIT15-0119]; Advanced Functional Materials SFO-Center at Linkoping University; International Interdisciplinary Laboratory for Advanced Functional Materials, Linkopings Universitet; Onnesjo Foundation; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation

    Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2020-02-17
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  • 85.
    Seitanidou, Maria S
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Blomgran, Robert
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences.
    Pushpamithran, Giggil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Modulating Inflammation in Monocytes Using Capillary Fiber Organic Electronic Ion Pumps2019In: Advanced Healthcare Materials, ISSN 2192-2640, E-ISSN 2192-2659, Vol. 8, no 19, article id 1900813Article in journal (Refereed)
    Abstract [en]

    An organic electronic ion pump (OEIP) delivers ions and drugs from a source, through a charge selective membrane, to a target upon an electric bias. Miniaturization of this technology is crucial and will provide several advantages, ranging from better spatiotemporal control of delivery to reduced invasiveness for implanted OEIPs. To miniaturize OEIPs, new configurations have been developed based on glass capillary fibers filled with an anion exchange membrane (AEM). Fiber capillary OEIPs can be easily implanted in proximity to targeted cells and tissues. Herein, the efficacy of such a fiber capillary OEIP for modulation of inflammation in human monocytes is demonstrated. The devices are located on inflammatory monocytes and local delivery of salicylic acid (SA) is initiated. Highly localized SA delivery results in a significant decrease in cytokine (tumor necrosis factor alpha and interleukin 6) levels after lipopolysaccharide stimulation. The findings-the first use of such capillary OEIPs in mammalian cells or systems-demonstrate the utility of the technology for optimizing transport and delivery of different therapeutic substances at low concentrations, with the benefit of local and controlled administration that limits the adverse effect of oral/systemic drug delivery.

    The full text will be freely available from 2020-09-10 13:45
  • 86.
    Seitanidou, Maria S
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel T
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Overcoming transport limitations in miniaturized electrophoretic delivery devices2019In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 19, no 8, p. 1427-1435Article in journal (Refereed)
    Abstract [en]

    Organic electronic ion pumps (OEIPs) have been used for delivery of biological signaling compounds, at high spatiotemporal resolution, to a variety of biological targets. The miniaturization of this technology provides several advantages, ranging from better spatiotemporal control of delivery to reduced invasiveness for implanted OEIPs. One route to miniaturization is to develop OEIPs based on glass capillary fibers that are filled with a polyelectrolyte (cation exchange membrane, CEM). These devices can be easily inserted and brought into close proximity to targeted cells and tissues and could be considered as a starting point for other fiber-based OEIP and iontronic technologies enabling favorable implantable device geometries. While characterizing capillary OEIPs we observed deviations from the typical linear current-voltage behavior. Here we report a systematic investigation of these irregularities by performing experimental characterizations in combination with computational modelling. The cause of the observed irregularities is due to concentration polarization established at the OEIP inlet, which in turn causes electric field-enhanced water dissociation at the inlet. Water dissociation generates protons and is typically problematic for many applications. By adding an ion-selective cap that separates the inlet from the source reservoir this effect is then, to a large extent, suppressed. By increasing the surface area of the inlet with the addition of the cap, the concentration polarization is reduced which thereby allows for significantly higher delivery rates. These results demonstrate a useful approach to optimize transport and delivery of therapeutic substances at low concentrations via miniaturized electrophoretic delivery devices, thus considerably broadening the opportunities for implantable OEIP applications.

    Download full text (pdf)
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  • 87.
    Sekretareva, Alina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Uppsala Univ, Sweden.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Volkov, Anton
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Evaluation of the Electrochemically Active Surface Area of Microelectrodes by Capacitive and Faradaic Currents2019In: CHEMELECTROCHEM, ISSN 2196-0216, Vol. 6, no 17, p. 4411-4417Article in journal (Refereed)
    Abstract [en]

    Two experimental methods to estimate the electrochemically active surface area (EASA) of microelectrodes are investigated. One method is based on electrocapacitive measurements and depends significantly on the surface roughness as well as on other parameters. The other method is based on faradaic current measurements and depends on the geometric surface area. The experimental results are supplemented with numerical modeling of electrodes with different surface roughness. A systematic study reveals a strong influence of the scale and arrangement of the surface roughness, the measurement potential and the electrolyte concentration on the EASA of microelectrodes estimated from the electrocapacitive measurements. The results show that electrocapacitive measurements should not be used to estimate the faradaic EASA of microelectrodes with a non-negligible surface roughness.

    The full text will be freely available from 2020-07-21 13:29
  • 88. Order onlineBuy this publication >>
    Shiran Chaharsoughi, Mina
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hybrid Plasmonics for Energy Harvesting and Sensing of Radiation and Heat2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The special optical properties of subwavelength metallic structures have opened up for numerous applications in different fields. The interaction of light with metal nanostructures leads to the excitation of collective oscillations of conduction-band electrons, known as plasmons. These plasmon excitations are responsible for the high absorption and high scattering of light in metallic nanostructures. High absorption of light and the subsequent temperature increase in the nanostructures make them suitable as point-like heat sources that can be controlled remotely by light.

    The research presented in this thesis focuses on the development and studies of hybrid devices that combine light-induced heating in plasmonic nanostructures with other materials and systems. Particular focus is put on hybrid organic-inorganic systems for applications in energy harvesting as well as in heat and radiation sensing. Harvesting energy from light fluctuations was achieved in a hybrid device consisting of plasmonic gold nanodisk arrays and a pyroelectric copolymer. In this concept, fast and efficient light-induced heating in the gold nanodisks modulated the temperature of the pyroelectric layer, which could be used to extract electrical energy from fluctuations in simulated sunlight.

    Integrating plasmonic nanostructures with complementary materials can also provide novel hybrid sensors, for monitoring of temperature, heat flux and radiation. In this thesis work, a hybrid sensor was designed based on the combination of a plasmonic gold nanohole layer with a pyroelectric copolymer and an ionic thermoelectric gel. The gold nanohole arrays acted both as broadband light absorbers in the visible to near-infrared spectral range of the solar spectrum and also as one of the electrodes of the sensor. In contrast to the constituent components when used separately, the hybrid sensor could provide both fast and stable signals upon heat or radiation stimuli, as well as enhanced equilibrium signals.

    Furthermore, a concept for heat and radiation mapping was developed that was highly sensitive and stable despite its simple structure. The concept consisted of a gel-like electrolyte connecting two separated metal nanohole electrodes on a substrate. Resembling traditional thermocouples, this concept could autonomously detect temperature changes but with several orders of magnitudes higher sensitivity. Owing to its promising sensing properties as well as its compatibility with inexpensive mass production methods on flexible substrates, such concept may be particularly interesting for electronic skin applications for health monitoring and for humanoid robotics. Finally, we improved the possibilities for the temperature mapping of the concept by modifying the structure from lateral to vertical form. Similar to the lateral device, the vertical temperature sensor showed high temperature sensitivity and stability in producing signals upon temperature changes.

    List of papers
    1. Hybrid Plasmonic and Pyroelectric Harvesting of Light Fluctuations
    Open this publication in new window or tab >>Hybrid Plasmonic and Pyroelectric Harvesting of Light Fluctuations
    Show others...
    2018 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071Article in journal (Refereed) Published
    Abstract [en]

    State-of-the-art solar energy harvesting systems based on photovoltaic technology require constant illumination for optimal operation. However, weather conditions and solar illumination tend to fluctuate. Here, a device is presented that extracts electrical energy from such light fluctuations. The concept combines light-induced heating of gold nanodisks (acting as plasmonic optical nanoantennas), and an organic pyroelectric copolymer film (poly(vinylidenefluoride-co-trifluoroethylene)), that converts temperature changes into electrical signals. This hybrid device can repeatedly generate current pulses, not only upon the onset of illumination, but also when illumination is blocked. Detailed characterization highlights the key role of the polarization state of the copolymer, while the copolymer thickness has minor influence on performance. The results are fully consistent with plasmon-assisted pyroelectric effects, as corroborated by combined optical and thermal simulations that match the experimental results. Owing to the tunability of plasmonic resonances, the presented concept is compatible with harvesting near infrared light while concurrently maintaining visible transparency.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2018
    Keywords
    Gold nanodisks, Plasmonic heating, Pyroelectric copolymers, Solar energy harvesting
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-148574 (URN)10.1002/adom.201701051 (DOI)000434349300001 ()
    Note

    Funding agencies: Wenner-Gren Foundations; Swedish Research Council [2015-05070]; Swedish Foundation for Strategic Research; AForsk Foundation; Royal Swedish Academy of Sciences; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Lin

    Available from: 2018-06-13 Created: 2018-06-13 Last updated: 2020-01-31
    2. Thermodiffusion-Assisted Pyroelectrics-Enabling Rapid and Stable Heat and Radiation Sensing
    Open this publication in new window or tab >>Thermodiffusion-Assisted Pyroelectrics-Enabling Rapid and Stable Heat and Radiation Sensing
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    2019 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 28, article id 1900572Article in journal (Refereed) Published
    Abstract [en]

    Sensors for monitoring temperature, heat flux, and thermal radiation are essential for applications such as electronic skin. While pyroelectric and thermoelectric effects are suitable candidates as functional elements in such devices, both concepts show individual drawbacks in terms of zero equilibrium signals for pyroelectric materials and small or slow response of thermoelectric materials. Here, these drawbacks are overcome by introducing the concept of thermodiffusion-assisted pyroelectrics, which combines and enhances the performance of pyroelectric and ionic thermoelectric materials. The presented integrated concept provides both rapid initial response upon heating and stable synergistically enhanced signals upon prolonged exposure to heat stimuli. Likewise, incorporation of plasmonic metasurfaces enables the concept to provide both rapid and stable signals for radiation-induced heating. The performance of the concept and its working mechanism can be explained by ion-electron interactions at the interface between the pyroelectric and ionic thermoelectric materials.

    Place, publisher, year, edition, pages
    Wiley-VCH Verlagsgesellschaft, 2019
    Keywords
    heat sensing; ionic thermodiffusion; plasmonic heating; pyroelectric copolymer
    National Category
    Other Materials Engineering
    Identifiers
    urn:nbn:se:liu:diva-159730 (URN)10.1002/adfm.201900572 (DOI)000478851700007 ()2-s2.0-85064476505 (Scopus ID)
    Note

    Funding Agencies|Swedish Foundation for Strategic Research; Swedish Research Council; AForsk Foundation; Wenner-Gren Foundations; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [200900971]

    Available from: 2019-08-19 Created: 2019-08-19 Last updated: 2020-01-31Bibliographically approved
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  • 89.
    Shiran Chaharsoughi, Mina
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhao, Dan
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Thermodiffusion-Assisted Pyroelectrics-Enabling Rapid and Stable Heat and Radiation Sensing2019In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 28, article id 1900572Article in journal (Refereed)
    Abstract [en]

    Sensors for monitoring temperature, heat flux, and thermal radiation are essential for applications such as electronic skin. While pyroelectric and thermoelectric effects are suitable candidates as functional elements in such devices, both concepts show individual drawbacks in terms of zero equilibrium signals for pyroelectric materials and small or slow response of thermoelectric materials. Here, these drawbacks are overcome by introducing the concept of thermodiffusion-assisted pyroelectrics, which combines and enhances the performance of pyroelectric and ionic thermoelectric materials. The presented integrated concept provides both rapid initial response upon heating and stable synergistically enhanced signals upon prolonged exposure to heat stimuli. Likewise, incorporation of plasmonic metasurfaces enables the concept to provide both rapid and stable signals for radiation-induced heating. The performance of the concept and its working mechanism can be explained by ion-electron interactions at the interface between the pyroelectric and ionic thermoelectric materials.

    Download full text (pdf)
    fulltext
  • 90.
    Shtepliuk, Ivan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. NASU, Ukraine.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Electrochemical Deposition of Copper on Epitaxial Graphene2020In: Applied Sciences, E-ISSN 2076-3417, APPLIED SCIENCES-BASEL, Vol. 10, no 4, article id 1405Article in journal (Refereed)
    Abstract [en]

    Understanding the mechanism of metal electrodeposition on graphene as the simplest building block of all graphitic materials is important for electrocatalysis and the creation of metal contacts in electronics. The present work investigates copper electrodeposition onto epitaxial graphene on 4H-SiC by experimental and computational techniques. The two subsequent single-electron transfer steps were coherently quantified by electrochemistry and density functional theory (DFT). The kinetic measurements revealed the instantaneous nucleation mechanism of copper (Cu) electrodeposition, controlled by the convergent diffusion of reactant to the limited number of nucleation sites. Cu can freely migrate across the electrode surface. These findings provide fundamental insights into the nature of copper reduction and nucleation mechanisms and can be used as a starting point for performing more sophisticated investigations and developing real applications.

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  • 91.
    Shtepliuk, Ivan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. NASU, Kyiv, Ukraine.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Insights into the Electrochemical Behavior of Mercury on Graphene/SiC Electrodes2019In: C — Journal of Carbon Research, ISSN 2311-5629, Vol. 5, no 3, article id 51Article in journal (Refereed)
    Abstract [en]

    Fast and real time detection of Mercury (Hg) in aqueous solutions is a great challenge due to its bio-accumulative character and the detrimental effect on human health of this toxic element. Therefore, development of reliable sensing platforms is highly desirable. Current research is aiming at deep understanding of the electrochemical response of epitaxial graphene to Mercury exposure. By performing cyclic voltammetry and chronoamperometry measurements as well as density functional theory calculations, we elucidate the nature of Hg-involved oxidation-reduction reactions at the graphene electrode and shed light on the early stages of Hg electrodeposition. The obtained critical information of Hg behavior will be helpful for the design and processing of novel graphene-based sensors.

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  • 92.
    Silverå Ejneby, Malin
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Migliaccio, Ludovico
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gicevicius, Mindaugas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Vilnius Univ, Lithuania.
    Derek, Vedran
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jakesova, Marie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Elinder, Fredrik
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Warsaw Univ Technol, Poland.
    Extracellular Photovoltage Clamp Using Conducting Polymer-Modified Organic Photocapacitors2020In: ADVANCED MATERIALS TECHNOLOGIES, ISSN 2365-709X, article id 1900860Article in journal (Refereed)
    Abstract [en]

    Optoelectronic control of physiological processes accounts for new possibilities ranging from fundamental research to treatment of disease. Among nongenetic light-driven approaches, organic semiconductor-based device platforms such as the organic electrolytic photocapacitor (OEPC) offer the possibility of localized and wireless stimulation with a minimal mechanical footprint. Optimization of efficiency hinges on increasing effective capacitive charge delivery. Herein, a simple strategy to significantly enhance the photostimulation performance of OEPC devices by employing coatings of the conducting polymer formulation poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), or PEDOT:PSS is reported. This modification increases the charge density of the stimulating photoelectrodes by a factor of 2-3 and simultaneously decreases the interfacial impedance. The electrophysiological effects of PEDOT:PSS-derivatized OEPCs on Xenopus laevis oocyte cells on membrane potential are measured and voltage-clamp techniques are used, finding an at-least twofold increase in capacitive coupling. The large electrolytic capacitance of PEDOT:PSS allows the OEPC to locally alter the extracellular voltage and keep it constant for long periods of time, effectively enabling a unique type of light-controlled membrane depolarization for measurements of ion channel opening. The finding that PEDOT:PSS-coated OEPCs can remain stable after a 50-day accelerated ageing test demonstrates that PEDOT:PSS modification can be applied for fabricating reliable and efficient optoelectronic stimulation devices.

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  • 93.
    Singh, Prem
    et al.
    Indian Inst Technol Mandi, India.
    Sonika,
    Indian Inst Technol Mandi, India.
    Gangadharan, Pranav K.
    CSIR Natl Chem Lab, India; Acad Sci and Innovat Res AcSIR, India.
    Khan, Ziyauddin
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kurungot, Sreekumar
    CSIR Natl Chem Lab, India; Acad Sci and Innovat Res AcSIR, India.
    Jaiswal, Amit
    Indian Inst Technol Mandi, India.
    Cubic Palladium Nanorattles with Solid Octahedron Gold Core for Catalysis and Alkaline Membrane Fuel Cell Applications2019In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 11, no 17, p. 4383-4392Article in journal (Refereed)
    Abstract [en]

    Herein, we report the synthesis of palladium nanorattles (Au-Pd NRTs) comprising of a gold octahedral core caged within a thin porous cubic palladium shell. The introduction of core-shell and porous architecture was realized by combining seed mediated and galvanic replacement reaction techniques. Next, we examined the catalytic efficiency of the nanocatalyst in comparison with solid palladium nanocube (Pd-NC) of similar size for the degradation of p-nitrophenol and organic dyes. The rate constant of Au-Pd NRTs was found nearly 12 times higher than the Pd-NCs. Further, we exploited our catalyst for electrochemical oxygen reduction reaction (ORR) and observed its high intrinsic ORR activity. Compared with commercialized Pt/C, the Au-Pd NRT displayed nearly comparable onset and half-wave potential values and excellent durability upon potential cycling. The system level validation in a single-cell mode of alkaline exchange membrane fuel cell also confirms the efficiency of the present catalyst to serve as a potential cathode catalyst for realistic device applications.

  • 94.
    Spyropoulos, George D.
    et al.
    Columbia Univ, NY 10027 USA.
    Savarin, Jeremy
    Columbia Univ, NY 10027 USA.
    Gomez, Eliot
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gelinas, Jennifer N.
    Columbia Univ, NY 10032 USA.
    Stavrinidou, Eleni
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Khodagholy, Dion
    Columbia Univ, NY 10027 USA.
    Transcranial Electrical Stimulation and Recording of Brain Activity using Freestanding Plant-Based Conducting Polymer Hydrogel Composites2019In: ADVANCED MATERIALS TECHNOLOGIES, ISSN 2365-709X, article id 1900652Article in journal (Refereed)
    Abstract [en]

    Transcranial electrical stimulation is a noninvasive neurostimulation technique with a wide range of therapeutic applications. However, current electrode materials are typically not optimized for this abiotic/biotic interface which requires high charge capacity, operational stability, and conformability. Here, a plant-based composite electrode material based on the combination of aloe vera (AV) hydrogel and a conducting polymer (CP; poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, PEDOT:PSS) is reported. This material system is fabricated into films and provides biocompatibility, conformability, and stability, while offering desirable electrical properties of the PEDOT:PSS. AVCP films are also molded onto the rough surface of the skull leading to a mechanically stable and robust interface. The in vivo efficacy of the AVCP films is verified to function as stimulating and recording electrodes by placing them on the skull of a rat and concomitantly inducing focal seizures and acquiring the evoked neural activity. AVCP films pave the way for high-quality biological interfaces that are broadly applicable and can facilitate advances in closed-loop responsive stimulation devices.

  • 95.
    Szroeder, Pawel
    et al.
    Kazimierz Wielki Univ, Poland.
    Sahalianov, Ihor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Radchenko, Taras
    NAS Ukraine, Ukraine.
    Tatarenko, Valentyn
    NAS Ukraine, Ukraine.
    Prylutskyy, Yuriy
    Taras Shevchenko Natl Univ, Ukraine.
    The strain- and impurity-dependent electron states and catalytic activity of graphene in a static magnetic field2019In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 96, article id UNSP 109284Article in journal (Refereed)
    Abstract [en]

    Harnessing the full potential of graphene for optoelectronic and electrochemical devices requires turn ling and goal-directed control of its electronic properties. We report a computational study of the electron density of states and catalytic activity of graphene in the perpendicular magnetic field. We focus on the influence of uniaxial strain, covalently bonded moieties, charged ions at graphene surface, and positively charged impurities located between graphene layer and substrate, on the Landau levels (LL) observed on density of states and the resulting catalytic activity. For this study, the reduction of ferricyanide to ferrocyanide serves as a benchmark electrochemical reaction. Results show that LLs strongly affect the shape of the cathodic reaction rate curve. Armchair strain and covalently bonded moieties do not affect the intensity of LLs. On the other hand, zigzag strain, charged ions represented by Gaussian-like potential, and positively charged impurities represented by Coulomb-like potential, give rise to a gradual disappearance of the LLs. Positively charged Coulomb-like impurities cause a shift of the density of states towards higher energy which results in an extraordinary increase of the standard rate constant by one order of magnitude at the impurities concentration of 0.1%.

  • 96.
    Tahira, Aneela
    et al.
    Lulea Univ Technol, Sweden.
    Ibupoto, Zafar Hussain
    Lulea Univ Technol, Sweden; Univ Sindh Jamshoro, Pakistan.
    Mazzaro, Raffaello
    Lulea Univ Technol, Sweden; CNR, Italy.
    You, Shuji
    Lulea Univ Technol, Sweden.
    Morandi, Vittorio
    CNR, Italy.
    Natile, Marta Maria
    CNR ICMATE CNR, Italy; Univ Padua, Italy.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Vomiero, Alberto
    Lulea Univ Technol, Sweden; Ca Foscari Univ Venice, Italy.
    Advanced Electrocatalysts for Hydrogen Evolution Reaction Based on Core-Shell MoS2/TiO2 Nanostructures in Acidic and Alkaline Media2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 3, p. 2053-2062Article in journal (Refereed)
    Abstract [en]

    Hydrogen production as alternative energy source is still a challenge due to the lack of efficient and inexpensive catalysts, alternative to platinum. Thus, stable, earth abundant, and inexpensive catalysts are of prime need for hydrogen production via hydrogen evolution reaction (HER). Herein, we present an efficient and stable electrocatalyst composed of earth abundant TiO2 nanorods decorated with molybdenum disulfide thin nanosheets, a few nanometers thick. We grew rutile TiO2 nanorods via the hydrothermal method on conducting glass substrate, and then we nucleated the molybdenum disulfide nanosheets as the top layer. This composite possesses excellent hydrogen evolution activity in both acidic and alkaline media at considerably low overpotentials (350 mV and 700 mV in acidic and alkaline media, respectively) and small Tafel slopes (48 and 60 mV/dec in acidic and alkaline conditions, respectively), which are better than several transition metal dichalcogenides, such as pure molybdenum disulfide and cobalt diselenide. A good stability in acidic and alkaline media is reported here for the new MoS2/TiO2 electrocatalyst. These results demonstrate the potential of composite electrocatalysts for HER based on earth abundant, cost-effective, and environmentally friendly materials, which can also be of interest for a broader range of scalable applications in renewable energies, such as lithium sulfur batteries, solar cells, and fuel cells.

  • 97.
    Teo, Mei Ying
    et al.
    Univ Auckland, New Zealand.
    RaviChandran, Narrendar
    Univ Auckland, New Zealand.
    Kim, Nara
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Kee, Seyoung
    KAUST, Saudi Arabia.
    Stuart, Logan
    Univ Auckland, New Zealand.
    Aw, Kean C.
    Univ Auckland, New Zealand.
    Stringer, Jonathan
    Univ Auckland, New Zealand.
    Direct Patterning of Highly Conductive PEDOT:PSS/Ionic Liquid Hydrogel via Microreactive Inkjet Printing2019In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 40, p. 37069-37076Article in journal (Refereed)
    Abstract [en]

    The gelation of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has gained popularity for its potential applications in three dimensions, while possessing tissue-like mechanical properties, high conductivity, and biocompatibility. However, the fabrication of arbitrary structures, especially via inkjet printing, is challenging because of the inherent gel formation. Here, microreactive inkjet printing (MRIJP) is utilized to pattern various 2D and 3D structures of PEDOT:PSS/IL hydrogel by in-air coalescence of PEDOT:PSS and ionic liquid (IL). By controlling the in-air position and Marangoni-driven encapsulation, single droplets of the PEDOT:PSS/IL hydrogel as small as a diameter of approximate to 260 mu m are fabricated within approximate to 600 mu s. Notably, this MRIJP-based PEDOT:PSS/IL has potential for freeform patterning while maintaining identical performance to those fabricated by the conventional spin-coating method. Through controlled deposition achieved via MRIJP, PEDOT:PSS/IL can be transformed into different 3D structures without the need for molding, potentially leading to substantial progress in next-generation bioelectronics devices.

  • 98.
    Urbanaviciute, Indre
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Meng, Xiao
    Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands .
    Biler, Michal
    Department of Chemistry – BMC, Uppsala University, Uppsala, Sweden.
    Wei, Yingfen
    Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands .
    Cornelissen, Tim D.
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Bhattacharjee, Subham
    Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Linares, Mathieu
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Swedish e-Science Research Centre (SeRC), Stockholm, Sweden.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Negative piezoelectric effect in an organic supramolecular ferroelectric2019In: Materials Horizons, ISSN 2051-6347, E-ISSN 2051-6355, Vol. 6, p. 1688-1698Article in journal (Refereed)
    Abstract [en]

    The vast majority of ferroelectric materials demonstrate a positive piezoelectric effect. Theoretically, the negative piezoelectric coefficient d33 could be found in certain classes of ferroelectrics, yet in practice, the number of materials showing linear longitudinal contraction with increasing applied field (d33 < 0) is limited to few ferroelectric polymers. Here, we measure a pronounced negative piezoelectric effect in the family of organic ferroelectric small-molecular BTAs (trialkylbenzene-1,3,5-tricarboxamides), which can be tuned by mesogenic tail substitution and structural disorder. While the large- and small-signal strain in highly-ordered thin-film BTA capacitor devices are dominated by intrinsic contributions and originates from piezostriction, rising disorder introduces additional extrinsic factors that boost the large-signal d33 up to −20 pm V’1 in short-tailed molecules. Interestingly, homologues with longer mesogenic tails show a large-signal electromechanical response that is dominated by the quadratic Maxwell strain with significant mechanical softening upon polarization switching, whereas the small-signal strain remains piezostrictive. Molecular dynamics and DFT calculations both predict a positive d33 for defect-free BTA stacks. Hence, the measured negative macroscopic d33 is attributed to the presence of structural defects that enable the dimensional effect to dominate the piezoelectric response of BTA thin films.

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    Negative piezoelectric effect in an organic supramolecular ferroelectric
  • 99.
    Vagin, Mikhail
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology.
    Sekretareva, Alina
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Stanford Univ, CA 94305 USA; Uppsala Univ, Sweden.
    Håkansson, Anna
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Graphens AB, Teknikringen 1F, SE-58330 Linkoping, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Graphens AB, Teknikringen 1F, SE-58330 Linkoping, Sweden.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Graphens AB, Teknikringen 1F, SE-58330 Linkoping, Sweden.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Bioelectrocatalysis on Anodized Epitaxial Graphene and Conventional Graphitic Interfaces2019In: CHEMELECTROCHEM, ISSN 2196-0216, Vol. 6, no 14, p. 3791-3796Article in journal (Refereed)
    Abstract [en]

    Graphitic materials exhibit significant anisotropy due to the difference in conductivity in a single layer and between adjacent layers. This anisotropy is manifested on epitaxial graphene (EG), which can be manipulated on the nanoscale in order to provide tailor-made properties. Insertion of defects into the EG lattice was utilized here for controllable surface modification with a model biocatalyst and the properties were quantified by both electrochemical and optical methods. A comparative evaluation of the electrode reaction kinetics on the enzyme-modified 2D material vs conventional carbon electrode materials revealed a significant enhancement of mediated bioelectrocatalysis at the nanoscale.

    The full text will be freely available from 2020-07-01 15:20
  • 100.
    Valiollahi Bisheh, Roudabeh
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gueskine, Viktor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Singh, Amritpal
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering. Shoolini Univ, India.
    Grigoriev, Sergey A.
    Natl Res Ctr Kurchatov Inst, Russia.
    Pushkarev, Artem S.
    Natl Res Ctr Kurchatov Inst, Russia; Natl Res Univ Moscow Power Engn Inst, Russia.
    Pushkareva, Irina V.
    Natl Res Ctr Kurchatov Inst, Russia; Natl Res Univ Moscow Power Engn Inst, Russia.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Khan, Ziyauddin
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Electrochemical hydrogen production on a metal-free polymer2019In: SUSTAINABLE ENERGY and FUELS, ISSN 2398-4902, Vol. 3, no 12, p. 3387-3398Article in journal (Refereed)
    Abstract [en]

    The exploration for true electrocatalytic reactions at organic conducting polymer electrodes, including chemisorption of a reactant and desorption of a product, is receiving renewed interest due to the profound implications it could have on low-cost large area electrochemical energy technology. Here, we finalize the debate about the ability of an organic electrode, more specifically poly(3,4-ethylenedioxythiophene) (PEDOT), to be an electrocatalyst for hydrogen production. This paper proves and covers fundamental studies of the hydrogen evolution reaction (HER) on PEDOT films. Both theory based on DFT (Density Functional Theory) and experimental studies using electrochemical techniques and operando mass spectrometry suggest a Volmer-Heyrovsky mechanism for the actual HER on PEDOT. It is shown that PEDOT reaches an exchange current density comparable to that of metals (i.e. Cu, Ni, and Au) and in addition does not form passivating oxide layers or suffer from chemical corrosion in acidic media. Finally, an electrolyzer stack using the organic polymer electrode demonstrates HER performance in real applications.

    The full text will be freely available from 2020-10-21 08:47
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