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  • 151.
    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
  • 152.
    Volkov, Anton
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Wijeratne, Kosala
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Mitraka, Evangelia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ail, Ujwala
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zhao, Dan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Wenzel Andreasen, Jens
    Technical University of Denmark, Denmark.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Stellenbosch University, South Africa.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zozoulenko, Igor
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Understanding the Capacitance of PEDOT:PSS2017In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 27, no 28, article id 1700329Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) is the most studied and explored mixed ion-electron conducting polymer system. PEDOT: PSS is commonly included as an electroactive conductor in various organic devices, e.g., supercapacitors, displays, transistors, and energy-converters. In spite of its long-term use as a material for storage and transport of charges, the fundamentals of its bulk capacitance remain poorly understood. Generally, charge storage in supercapacitors is due to formation of electrical double layers or redox reactions, and it is widely accepted that PEDOT: PSS belongs to the latter category. Herein, experimental evidence and theoretical modeling results are reported that significantly depart from this commonly accepted picture. By applying a two-phase, 2D modeling approach it is demonstrated that the major contribution to the capacitance of the two-phase PEDOT: PSS originates from electrical double layers formed along the interfaces between nanoscaled PEDOT-rich and PSS-rich interconnected grains that comprises two phases of the bulk of PEDOT: PSS. This new insight paves a way for designing materials and devices, based on mixed ion-electron conductors, with improved performance.

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  • 153.
    Wadeasa, Amal
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Tzamalis, G.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Solution processed ZnO nanorods/polyfluorene semiconductor heterojunctions with white light photoluminescenceManuscript (preprint) (Other academic)
    Abstract [en]

    Hybrid inorganic-organic semiconductor heterojunctions are nowadays scrutinized for optoelectronic devices, such as solar cells and light emitting diodes. Here, ZnOnanorods/ polyfluorene heterojunctions have been entirely fabricated from solution by wet chemistry and low temperature processes. The morphology of the polyfluorene film appears to be an important parameter to control the growth of the ZnO nanorods and affects their optical properties. The visible emission of the conjugated polymer and the ZnO are complementary and provide a broad emission in the visible. Because of its solution processability and broad emission, the ZnO/polyfluorene heterojunction is promising for large area white lightning applications.

  • 154.
    Wadeasa, Amal
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Tzamalis, G
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sehati, Parisa
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Solution processed ZnO nanowires/polyfluorene heterojunctions for large area lightening2010In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 490, no 4-6, p. 200-204Article in journal (Refereed)
    Abstract [en]

    Hybrid inorganic-organic semiconductor heterojunctions are nowadays scrutinized for optoelectronic devices, such as solar cells and light emitting diodes. Here, ZnO nanowires/polyfluorene heterojunctions have been entirely fabricated from solution by wet chemistry and low temperature processes. The transparent plastic electrode PEDOT injects holes in the polyfluorene, while the electrons are injected via the ZnO-Au contact, thus avoiding the use of air sensitive low work function metals. The hybrid inorganic-organic light emitting diode emits almost white light. Because of its solution processability, stable cathode, low cost and low temperature process, the ZnO/polymer heterojunction devices are promising for large area lightening applications.

  • 155.
    Wang, Hui
    et al.
    Linköping University, Department of Science and Technology.
    Ail, Ujwala
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Gabrielsson, Roger
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ionic Seebeck Effect in Conducting Polymers2015In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 5, no 11, article id 1500044Article in journal (Refereed)
    Abstract [en]

    Conducting polymers display an ionic thermoelectric effect in addition to the known electronic thermoelectric effect. Their Seebeck coefficient is as large as ≈200 μV K−1. This finding discloses a new possible approach to improve the thermoelectric properties of conducting polymers by combining various types of charge carriers of the same sign.

  • 156.
    Wang, Hui
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Khan, Zia Ullah
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zhao, Dan
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ionic Thermoelectric effect in Polyelectrolytes2015Manuscript (preprint) (Other academic)
  • 157.
    Wang, Hui
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Zhao, Dan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Puzinas, Skomantas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ionic Thermoelectric Figure of Merit for Charging of Supercapacitors2017In: ADVANCED ELECTRONIC MATERIALS, ISSN 2199-160X, Vol. 3, no 4, article id 1700013Article in journal (Refereed)
    Abstract [en]

    Thermoelectric materials enable conversion of heat to electrical energy. The performance of electronic thermoelectric materials is typically evaluated using a figure of merit ZT = sigma alpha 2T/lambda, where sigma is the conductivity, alpha is the so-called Seebeck coefficient, and lambda is the thermal conductivity. However, it has been unclear how to best evaluate the performance of ionic thermoelectric materials, like ionic solids and electrolytes. These systems cannot be directly used in a traditional thermoelectric generator, because they are based on ions that cannot pass the interface between the thermoelectric material and external metal electrodes. Instead, energy can be harvested from the ionic thermoelectric effect by charging a supercapacitor. In this study, the authors investigate the ionic thermoelectric properties at varied relative humidity for the polyelectrolyte polystyrene sulfonate sodium and correlate these properties with the charging efficiency when used in an ionic thermoelectric supercapacitor (ITESC). In analogy with electronic thermoelectric generators, the results show that the charging efficiency of the ITESC can be quantitatively related to the figure of merit ZT(i) = sigma i alpha i2T/lambda. This means that the performance of ionic thermoelectric materials can also be compared and predicted based on the ZT, which will be highly valuable in the design of high-performance ITESCs.

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  • 158.
    Wang, Suhao
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Himmelberger, Scott
    Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
    Puzinas, Skomantas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Salleo, Alberto
    Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Experimental evidence that short-range intermolecular aggregation is sufficient for efficient charge transport in conjugated polymers2015In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 34, p. 10599-10604Article in journal (Refereed)
    Abstract [en]

    Efficiency, current throughput, and speed of electronic devices are to a great extent dictated by charge carrier mobility. The classic approach to impart high carrier mobility to polymeric semiconductors has often relied on the assumption that extensive order and crystallinity are needed. Recently, however, this assumption has been challenged, because high mobility has been reported for semiconducting polymers that exhibit a surprisingly low degree of order. Here, we show that semiconducting polymers can be confined into weakly ordered fibers within an inert polymer matrix without affecting their charge transport properties. In these conditions, the semiconducting polymer chains are inhibited from attaining long-range order in the p-stacking or alkyl-stacking directions, as demonstrated from the absence of significant X-ray diffraction intensity corresponding to these crystallographic directions, yet still remain extended along the backbone direction and aggregate on a local length scale. As a result, the polymer films maintain high mobility even at very low concentrations. Our findings provide a simple picture that clarifies the role of local order and connectivity of domains.

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  • 159.
    Wang, Suhao
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Sun, Hengda
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ail, Ujwala
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Persson, Per O. Å.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Andreasen, Jens W.
    Technical University of Denmark, Department of Energy Conversion and Storage, Roskilde, Denmark.
    Thiel, Walter
    Max‐Planck‐Institut für Kohlenforschung, Mülheim an der Ruhr, Germany.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fazzi, Daniele
    Max‐Planck‐Institut für Kohlenforschung, Mülheim an der Ruhr, Germany.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers2016In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 28, no 48, p. 10764-Article in journal (Refereed)
    Abstract [en]

    Ladder-type “torsion-free” conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform “structurally distorted” donor–acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure–function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers.

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  • 160.
    Wang, Suhao
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Sun, Hengda
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Erdmann, Tim
    Tech Univ Dresden, Germany; Leibniz Inst Polymerforsch Dresden eV, Germany; Flexterra Corp, IL 60077 USA; IBM Almaden Res Ctr, CA 95120 USA.
    Wang, Gang
    Northwestern Univ, IL 60208 USA.
    Fazzi, Daniele
    Max Planck Inst Kohlenforsch, Germany; Univ Cologne, Germany.
    Lappan, Uwe
    Leibniz Inst Polymerforsch Dresden eV, Germany.
    Puttisong, Yuttapoom
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Chen, Zhihua
    Flexterra Corp, IL 60077 USA.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Kiriy, Anton
    Tech Univ Dresden, Germany; Leibniz Inst Polymerforsch Dresden eV, Germany.
    Voit, Brigitte
    Tech Univ Dresden, Germany; Leibniz Inst Polymerforsch Dresden eV, Germany.
    Marks, Tobin J.
    Northwestern Univ, IL 60208 USA; Northwestern Univ, IL 60208 USA.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Flexterra Corp, IL 60077 USA; Northwestern Univ, IL 60208 USA; Northwestern Univ, IL 60208 USA.
    Facchetti, Antonio
    Flexterra Corp, IL 60077 USA; Northwestern Univ, IL 60208 USA; Northwestern Univ, IL 60208 USA.
    A Chemically Doped Naphthalenediimide-Bithiazole Polymer for n-Type Organic Thermoelectrics2018In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, no 31, article id 1801898Article in journal (Refereed)
    Abstract [en]

    The synthesis of a novel naphthalenediimide (NDI)-bithiazole (Tz2)-based polymer [P(NDI2OD-Tz2)] is reported, and structural, thin-film morphological, as well as charge transport and thermoelectric properties are compared to the parent and widely investigated NDI-bithiophene (T2) polymer [P(NDI2OD-T2)]. Since the steric repulsions in Tz2 are far lower than in T2, P(NDI2OD-Tz2) exhibits a more planar and rigid backbone, enhancing p-p chain stacking and intermolecular interactions. In addition, the electron-deficient nature of Tz2 enhances the polymer electron affinity, thus reducing the polymer donor-acceptor character. When n-doped with amines, P(NDI2OD-Tz2) achieves electrical conductivity (approximate to 0.1 S cm(-1)) and a power factor (1.5 mu W m(-1) K-2) far greater than those of P(NDI2OD-T2) (0.003 S cm(-1) and 0.012 mu W m(-1) K-2, respectively). These results demonstrate that planarized NDI-based polymers with reduced donor-acceptor character can achieve substantial electrical conductivity and thermoelectric response.

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  • 161.
    Wang, Xiaodong
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Improving the stability of water-gated organic transistors for sensing applicationsManuscript (preprint) (Other academic)
    Abstract [en]

    The instability of water-gated organic transistors is a major obstacle for their sensing applications in aqueous media. In the present work, we demonstrate that adding a fluorinated ion exchange membrane, Nafion, on a water-gated organic transistor can increase significantly the stability of the device to air exposure. In addition, choosing a suitable operating voltage range, e.g. Vg=0 ↔ -0.7 V, is shown to be crucial for achieving stable (repeatable) measurements in aqueous media. It is also feasible to exploit this kind of transistor as a chemical sensor to discriminate different chemicals which are dissolved in water.

  • 162.
    Wang, Xiaodong
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Laiho, Ari
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Remanent polarization in a cryptand-polyanion bilayer implemented in an organic field effect transistor2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 2, p. 023305-Article in journal (Refereed)
    Abstract [en]

    We investigate the possibility to maintain an electric polarization in an organic bilayer via ion trapping, i.e., without any external bias. In the cryptand-polyanion bilayer, ions of specific size can be strongly coordinated with organic macrocyclic molecules. Cations move from the polyanion layer to the cryptand layer upon applying a bias and are trapped in this layer. As a result, the voltage dependence of the polarization displays a hysteresis. The bilayer is then advantageously used as an electronic insulating layer in an organic field effect transistor. The ions trapping and de-trapping can be followed by the amplitude of the threshold voltage (V(th)) shift as well as its temporal evolution.

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  • 163.
    Wang, Xiaodong
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Larsson, Oscar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Platt, Duncan
    Acreo AB.
    Nordlinder, Staffan
    WebShape AB.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    An all-printed wireless humidity sensor label2012In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 166-167, p. 556-561Article in journal (Refereed)
    Abstract [en]

    Printed electronics promise various kinds of sensor circuit labels, for applications in distributed sensing and monitoring, which can be manufactured using traditional printing tools at very low cost. Elevated humidity levels or water leakages cause tremendous costs in our society, such as in construction industries and in transportations. Distributed monitoring and remote sensing of the humidity level inside walls of buildings and packages is therefore desired and urgently needed. Here, we report a wireless humidity sensor label that is manufactured using screen-printing and dry-phase patterning. The sensor label includes a planar antenna, a tuning capacitor and a printed sensor-capacitor head. Through electromagnetic coupling between a reader and the printed sensor label, changes in humidity level were remotely detected and read-out as a shift of the resonant frequency. The manufacturing process of the humidity sensor label is fully compatible with inexpensive, reel-to-reel processing technologies, thus enabling low cost production.

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  • 164.
    Wang, Xiaodong
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Platt, Duncan
    Acreo AB, Norrköping, Sweden.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Printed low loss capacitors for use in a wireless humidity sensor labelManuscript (preprint) (Other academic)
    Abstract [en]

    A low loss printed capacitor is achieved by using a screen printable benzocyclobutene-based solution. The dissipation factor is measured to be 0.001 at frequencies around 3 MHz, which is low compared to commercially available dielectric inks with dissipation factors of ~0.05 in the same frequency region. By incorporating low loss printed capacitors with a planar antenna and a printed humidity sensor capacitor, a humidity sensor label which resonates at 3 MHz is demonstrated. The label is fully printed on a flexible substrate pre-patterned with the antenna and the manufacturing process is compatible with low-cost reelto-reel processing technology. The quality factor (Q factor) of the sensor label is enhanced up to about 15 in ambient environment. This allows readout of the sensor response at a distance and through damping materials such as walls in a building.

  • 165.
    Weathers, Annie
    et al.
    University of Texas Austin, TX 78712 USA.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Brooke, Robert
    University of S Australia, Australia.
    Evans, Drew
    University of S Australia, Australia.
    Pettes, Michael T.
    University of Texas Austin, TX 78712 USA.
    Wenzel Andreasen, Jens
    Technical University of Denmark, Denmark.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Shi, Li
    University of Texas Austin, TX 78712 USA.
    Significant Electronic Thermal Transport in the Conducting Polymer Poly(3,4-ethylenedioxythiophene)2015In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 27, no 12, p. 2101-2106Article in journal (Refereed)
    Abstract [en]

    Suspended microdevices are employed to measure the in-plane electrical conductivity, thermal conductivity, and Seebeck coefficient of suspended poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. The measured thermal conductivity is higher than previously reported for PEDOT and generally increases with the electrical conductivity. The increase exceeds that predicted by the Wiedemann-Franz law for metals and can be explained by significant electronic thermal transport in PEDOT.

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  • 166.
    Wee, Grace
    et al.
    School of Materials Science and Engineering Nanyang Technological University Singapore.
    Larsson, Oscar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Srinivasan, Madhavi
    School of Materials Science and Engineering Nanyang Technological University Singapore.
    Berggren, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Mhaisalkar, Subodh
    School of Materials Science and Engineering Nanyang Technological University Singapore.
    Effect of the Ionic Conductivity on the Performance of Polyelectrolyte-Based Supercapacitors2010In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 20, no 24, p. 4344-4350Article in journal (Refereed)
    Abstract [en]

    In the emerging technology field of printed electronics, circuits are envisioned to be powered with printed energy sources, such as printed batteries and printed supercapacitors (SCs). For manufacturing and reliability issues, solid electrolytes are preferred instead of liquid electrolytes. Here, a solid-state, polyanionic proton conducting electrolyte, poly(styrenesulfonic acid) (PSS:H), is demonstrated for the first time as an effective ion conducting electrolyte medium in SCs with electrodes based on carbon nanotube (CNT) networks. The effect of the ionic conductivity in the PSS:H film of those SCs is studied at different levels of relative humidity (RH) with impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge techniques. High capacitance values (85 F g(-1) at 80% RH) are obtained for these SCs due to the extremely high effective electrode area of the CNTs and the enhanced ionic conductivity of the PSS: H film at increasing RH level. The charging dynamics are primarily limited by the ionic conductivity of the electrolyte rather than a poor contact between the electrolyte and the CNT electrodes. The use of polyelectrolytes in SCs provides high mechanical strength and flexibility, while maintaining a high capacitance value, enabling a new generation of printable solid-state charge storage devices.

  • 167.
    Wijeratne, Kosala
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ail, Ujwala
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Brooke, Robert
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    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 Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Bulk electronic transport impacts on electron transfer at conducting polymer electrode-electrolyte interfaces.2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, no 7, p. 11899-11904Article in journal (Refereed)
    Abstract [en]

    Electrochemistry is an old but still flourishing field of research due to the importance of the efficiency and kinetics of electrochemical reactions in industrial processes and (bio-)electrochemical devices. The heterogeneous electron transfer from an electrode to a reactant in the solution has been well studied for metal, semiconductor, metal oxide, and carbon electrodes. For those electrode materials, there is little correlation between the electronic transport within the electrode material and the electron transfer occurring at the interface between the electrode and the solution. Here, we investigate the heterogeneous electron transfer between a conducting polymer electrode and a redox couple in an electrolyte. As a benchmark system, we use poly(3,4-ethylenedioxythiophene) (PEDOT) and the Ferro/ferricyanide redox couple in an aqueous electrolyte. We discovered a strong correlation between the electronic transport within the PEDOT electrode and the rate of electron transfer to the organometallic molecules in solution. We attribute this to a percolation-based charge transport within the polymer electrode directly involved in the electron transfer. We show the impact of this finding by optimizing an electrochemical thermogalvanic cell that transforms a heat flux into electrical power. The power generated by the cell increased by four orders of magnitude on changing the morphology and conductivity of the polymer electrode. As all conducting polymers are recognized to have percolation transport, we believe that this is a general phenomenon for this family of conductors.

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  • 168.
    Wijeratne, Kosala
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Vagin, Mikhail
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Brooke, Robert
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Poly(3,4-ethylenedioxythiophene)-Tosylate (PEDOT-Tos) electrode in Thermogalvanic Cells2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 37, p. 19619-19625Article in journal (Refereed)
    Abstract [en]

    The interest in thermogalvanic cells (TGCs) has grown because it is a candidate technology for harvesting electricity from natural and waste heat. However, the cost of TGCs has a major component due to the use of the platinum electrode. Here, we investigate new alternative electrode material based on conducting polymers, more especially poly(3,4-ethylenedioxythiophene)-Tosylate (PEDOT-Tos) together with the Ferro/Ferricyanide redox electrolyte. The power generated by the PEDOT-Tos based TGCs increases with the conducting polymer thickness/multilayer and reaches values similar to the flat platinum electrode based TGCs. The physics and chemistry behind this exciting result as well as the identification of the limiting phenomena are investigated by various electrochemical techniques. Furthermore, a preliminary study is provided for the stability of the PEDOT-Tos based TGCs.

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  • 169.
    Willfahrt, Andreas
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Stuttgart Media Univ, Germany.
    Steiner, Erich
    Stuttgart Media Univ, Germany.
    Hoetzel, Jonas
    Stuttgart Media Univ, Germany.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Printable acid-modified corn starch as non-toxic, disposable hydrogel-polymer electrolyte in supercapacitors2019In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 125, no 7, article id 474Article in journal (Refereed)
    Abstract [en]

    Corn starch and citric acid, two low-cost and abundant materials, were used for establishing a novel screen printable hydrogel for printed electronics applications. Corn starch was modified with citric acid by melt-blending; the so obtained thermoplastic starch was ground to powder and added to a water-starch suspension. Ultrasonication was used to prepare hydrogels of different citric acid concentrations. The most promising hydrogel contained 10% citric acid by weight, provided an ionic conductivity of (2.30 +/- 0.07)mScm(-1) and appropriate rheological properties for screen and stencil printing. The hydrogel shows superb printability and prolonged stability against degradation. The corn starch hydrogel was used as printable gel polymer electrolyte in fully printed supercapacitors. The specific capacitance of the printed supercapacitor reached 54Fg(-1). The printable hydrogel-polymer electrolyte is easy to produce without in-depth chemical knowledge, is based on widely used and non-toxic materials, and may be used as a functional layer in other printed electronics applications such as printed batteries.

    The full text will be freely available from 2020-06-22 07:23
  • 170.
    Xuan, Yu
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Desbief, S.
    Service de Chimie des Matériaux Nouveaux, Université de Mons (UMONS), Place du Parc 20, B-7000 Mons, Belgium.
    Leclére, P.
    Service de Chimie des Matériaux Nouveaux, Université de Mons (UMONS), Place du Parc 20, B-7000 Mons, Belgium.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Lazzaroni, R.
    Service de Chimie des Matériaux Nouveaux, Université de Mons (UMONS), Place du Parc 20, B-7000 Mons, Belgium.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Cornil, .
    Service de Chimie des Matériaux Nouveaux, Université de Mons (UMONS), Place du Parc 20, B-7000 Mons, Belgium.
    Emin, D.
    Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Thermoelectric properties of conducting polymers: The case of poly(3-hexylthiophene)2010In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, no 11, p. 115454-115463Article in journal (Refereed)
  • 171.
    Xuan, Yu
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sandberg, Mats
    ACREO AB, Norrköping.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    An all-polymer-air PEDOT battery2012In: Organic electronics, ISSN 1566-1199, E-ISSN 1878-5530, Vol. 13, no 4, p. 632-637Article in journal (Refereed)
    Abstract [en]

    Mass-produced organic electronics for internet-of-things, point of care diagnostics, smart labels and more suggest development of a “green” and recyclable electronics. One of the greatest challenges in achieving such a technology platform is to establish low-cost batteries that are metal-free. Here, we demonstrate a thin all polymer-air battery where the anode and cathode are based on the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Polyethyleneimine (PEI) is combined with the PEDOT electrode to ensure air stability of its neutral or rather “low oxidized” form at the anode, while PEDOT is in its oxidized state at the cathode. The difference in the oxidation level between the two PEDOT electrodes produces an open circuit voltage of about 0.5 V. Upon discharge, PEI is consumed at the PEDOT anode, while O2 reacts with the PEDOT cathode; thus demonstrating the first all-polymer-air battery.

  • 172.
    Zhang, Qian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Jiao, Fei
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. 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.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and 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.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Ground-state charge transfer for NIR absorption with donor/acceptor molecules: interactions mediated via energetics and orbital symmetries2017In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 2, p. 275-281Article in journal (Refereed)
    Abstract [en]

    The interactions between electron donors (D) and acceptors (A) of organic semiconducting molecules are of great interest to organic electronics, e.g. electrical doping of organic semiconductors (OSCs), photo-generation of charges in organic solar cells, and light-emitting/detecting devices based on OSCs. A blend of D/A OSC is typically characterized by weak van der Waals interactions or integer charge transfer (ICT) between neighboring D/A molecules. In between these two scenarios of physical blends and ICT complexes, orbital hybridization between adjacent D/A molecules serves as a third alternative, characterized by an in situ formation of a ground state complex featuring partial charge transfer between participating donor and acceptor molecules. In this work is presented a comprehensive experimental study on partial charge-transfer complex (CPX) formed via orbital hybridization. Thiophenes and phthalocyanines are used as electron donors, while acceptor molecules of different geometries and electron affinities are employed with the aim to clarify how orbital symmetry, energy level alignment and steric hindrance affect orbital hybridization and subsequent tuning of the optical band-gap into the near infrared (NIR) region.

  • 173.
    Zhao, Dan
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ionic thermoelectric gating organic transistors2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 14214Article in journal (Refereed)
    Abstract [en]

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (similar to 100 mu V K-1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (similar to 10,000 mu V K-1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins.

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  • 174.
    Zhao, Dan
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Martinelli, Anna
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg.
    Willfahrt, Andreas
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fischer, Thomas
    Innovative Applications of The Printing Technologies, Stuttgart Media University.
    Bernin, Diana
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Shahi, Maryam
    Department of Physics and Astronomy, University of Kentucky.
    Brill, Joseph
    Department of Physics and Astronomy, University of Kentucky.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Polymer gels with tunable ionic Seebeck coefficient for ultra-sensitive printed thermopiles2019In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 1093Article in journal (Refereed)
    Abstract [en]

    Measuring temperature and heat flux is important for regulating any physical, chemical, and biological processes. Traditional thermopiles can provide accurate and stable temperature reading but they are based on brittle inorganic materials with low Seebeck coefficient, and are difficult to manufacture over large areas. Recently, polymer electrolytes have been proposed for thermoelectric applications because of their giant ionic Seebeck coefficient, high flexibility and ease of manufacturing. However, the materials reported to date have positive Seebeck coefficients, hampering the design of ultra-sensitive ionic thermopiles. Here we report an “ambipolar” ionic polymer gel with giant negative ionic Seebeck coefficient. The latter can be tuned from negative to positive by adjusting the gel composition. We show that the ion-polymer matrix interaction is crucial to control the sign and magnitude of the ionic Seebeck coefficient. The ambipolar gel can be easily screen printed, enabling large-area device manufacturing at low cost.

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  • 175.
    Zhao, Dan
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Hui
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Ullah Khan, Zia
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Chen, J. C.
    Xiamen University, Peoples R China.
    Gabrielsson, Roger
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ionic thermoelectric supercapacitors2016In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 9, no 4, p. 1450-1457Article in journal (Refereed)
    Abstract [en]

    Temperature gradients are generated by the sun and a vast array of technologies and can induce molecular concentration gradients in solutions via thermodiffusion (Soret effect). For ions, this leads to a thermovoltage that is determined by the thermal gradient Delta T across the electrolyte, together with the ionic Seebeck coefficient alpha(i). So far, redox-free electrolytes have been poorly explored in thermoelectric applications due to a lack of strategies to harvest the energy from the Soret effect. Here, we report the conversion of heat into stored charge via a remarkably strong ionic Soret effect in a polymeric electrolyte (Seebeck coefficients as high as alpha(i) = 10 mV K-1). The ionic thermoelectric supercapacitor (ITESC) is charged under a temperature gradient. After the temperature gradient is removed, the stored electrical energy can be delivered to an external circuit. This new means to harvest energy is particularly suitable for intermittent heat sources like the sun. We show that the stored electrical energy of the ITESC is proportional to (Delta T alpha(i))(2). The resulting ITESC can convert and store several thousand times more energy compared with a traditional thermoelectric generator connected in series with a supercapacitor.

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  • 176.
    Zotti, G.
    et al.
    Istituto CNR l'Energetica Interfasi, C.o Stati Uniti 4, 35127 Padova, Italy.
    Zecchin, S.
    Istituto CNR l'Energetica Interfasi, C.o Stati Uniti 4, 35127 Padova, Italy.
    Schiavon, G.
    Istituto CNR l'Energetica Interfasi, C.o Stati Uniti 4, 35127 Padova, Italy.
    Louwet, F.
    R and D Materials Research, Chemistry Department, Agfa Gevaert N.V., Septelaan 27, B-2640 Mortsel, Belgium.
    Groenendaal, L.
    R and D Materials Research, Chemistry Department, Agfa Gevaert N.V., Septelaan 27, B-2640 Mortsel, Belgium.
    Crispin, Xavier
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Osikowicz, Wojciech
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Salaneck, William R
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Fahlman, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Electrochemical and XPS studies toward the role of monomeric and polymeric sulfonate counterions in the synthesis, composition, and properties of poly(3,4-ethylenedioxythiophene)2003In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 36, no 9, p. 3337-3344Article in journal (Refereed)
    Abstract [en]

    Electrochemically prepared poly(3,4-ethylenedioxythiophene) (PEDT) poly(styrenesulfonate) (PSS), produced from acidic (PSSH) and basic (PSSNa) PSS, was characterized by cyclic voltammetry CV, UV-vis spectroscopy, in situ conductivity, and XPS spectroscopy and was compared with electrochemically prepared PEDT/tosylate and chemically prepared PEDT/PSS. CV analysis shows that the polymer synthesis is strongly affected by the nucleophilic character of the counteranion. Although CV and UV-vis spectroscopy show that the structure and degree of polymerization (oligomeric, ca. 10 EDT units) of the PEDT backbone is the same for all polymers, XPS is able to explain the different conductivity values for these materials (ranging from 1 S cm-1 for PEDT/PSSNa to 400-450 S cm-1 for PEDT/tosylate) based on doping level and composition. In particular, critical results are observed to be the ratios between sulfonate and thiophene units in the polymers: the higher the PEDT concentration, the higher the conductivity. XPS also explains by solvent-induced nanometer-scale segregation between PEDT/PSS and excess PSS particles the often reported conductivity enhancement of chemically prepared PEDT/PSS upon treatment with polar solvents.

  • 177.
    Zozoulenko, Igor
    et al.
    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, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Chalmers Univ Technol, Sweden.
    Singh, Sandeep Kumar
    Linköping University, Department of Science and Technology. 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.
    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.
    Polarons, Bipolarons, And Absorption Spectroscopy of PEDOT2019In: ACS APPLIED POLYMER MATERIALS, ISSN 2637-6105, Vol. 1, no 1, p. 83-94Article in journal (Refereed)
    Abstract [en]

    Electronic structure and optical absorption spectra of poly(3,4-ethyl-enedioxythiophene) (PEDOT) for different oxidation levels were studied using density functional theory (DFT) and time-dependent DFT. It is shown, that the DFT-based predictions for the polaronic and bipolaronic states and the nature of corresponding optical transitions are qualitatively different from the widely used traditional picture based on semi-empirical pre-DFT approaches that still dominate the current literature. On the basis of the results of our calculations, the experimental Vis/NIR absorbance spectroscopy and the electron paramagnetic resonance spectroscopy are re-examined, and a new interpretation of the measured spectra and the spin signal, which is qualitatively different from the traditional interpretation, is provided. The findings and conclusions concerning the nature of polaronic and bipolaronic states, band structure and absorption spectra presented for PEDOT, are generic for a wide class of conducting polymers (such as polythiophenes and their derivatives) that have a similar structure of monomer units.

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