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Wang, C., Zhang, W., Meng, X., Bergqvist, J., Liu, X., Genene, Z., . . . Fahlman, M. (2017). Ternary Organic Solar Cells with Minimum Voltage Losses. Advanced Energy Materials, 7(21), Article ID 1700390.
Open this publication in new window or tab >>Ternary Organic Solar Cells with Minimum Voltage Losses
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2017 (English)In: Advanced Energy Materials, ISSN 1614-6840, Vol. 7, no 21, article id 1700390Article in journal (Refereed) Published
Abstract [en]

A new strategy for designing ternary solar cells is reported in this paper. A low-bandgap polymer named PTB7-Th and a high-bandgap polymer named PBDTTS-FTAZ sharing the same bulk ionization potential and interface positive integer charge transfer energy while featuring complementary absorption spectra are selected. They are used to fabricate efficient ternary solar cells, where the hole can be transported freely between the two donor polymers and collected by the electrode as in one broadband low bandgap polymer. Furthermore, the fullerene acceptor is chosen so that the energy of the positive integer charge transfer state of the two donor polymers is equal to the energy of negative integer charge transfer state of the fullerene, enabling enhanced dissociation of all polymer donor and fullerene acceptor excitons and suppressed bimolecular and trap assistant recombination. The two donor polymers feature good miscibility and energy transfer from high-bandgap polymer of PBDTTS-FTAZ to low-bandgap polymer of PTB7-Th, which contribute to enhanced performance of the ternary solar cell.

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
Keyword
binary equivalent, minimum voltage losses, same bulk and interface energy, ternary solar cells
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:liu:diva-143026 (URN)10.1002/aenm.201700390 (DOI)000414711100002 ()2-s2.0-85025441174 (Scopus ID)
Note

Funding agencies: Knut and Alice Wallenberg Foundation; Swedish Research Council [2016-05498]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]; Goran Gustafsson Foundat

Available from: 2017-11-15 Created: 2017-11-15 Last updated: 2017-12-05Bibliographically approved
Malti, A., Edberg, J., Granberg, H., Ullah Khan, Z., Andreasen, J. W., Liu, X., . . . Berggren, M. (2016). An Organic Mixed Ion–Electron Conductor for Power Electronics. Advanced Science, Article ID 1500305.
Open this publication in new window or tab >>An Organic Mixed Ion–Electron Conductor for Power Electronics
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2016 (English)In: Advanced Science, ISSN 2198-3844, article id 1500305Article in journal (Refereed) Published
Abstract [en]

A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2016
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-123225 (URN)10.1002/advs.201500305 (DOI)000370336500011 ()
Note

Funding agencies:  Knut and Alice Wallenberg foundation [KAW 2011.0050]; Onnesjo Foundation; Advanced Functional Materials Center at Linkoping University; Stiftelsen for strategisk forskning (SSF); RISE Research Institutes of Sweden; U.S. National Science Foundation [DMR-12

Available from: 2015-12-08 Created: 2015-12-08 Last updated: 2018-02-15
Bao, Q., Fabiano, S., Andersson, M., Braun, S., Sun, Z., Crispin, X., . . . Fahlman, M. (2016). Energy Level Bending in Ultrathin Polymer Layers Obtained through Langmuir-Shafer Deposition. Advanced Functional Materials, 26(7), 1077-1084
Open this publication in new window or tab >>Energy Level Bending in Ultrathin Polymer Layers Obtained through Langmuir-Shafer Deposition
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2016 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 7, p. 1077-1084Article in journal (Refereed) Published
Abstract [en]

The semiconductor-electrode interface impacts the function and the performance of (opto) electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultrathin films on electrodes typically form islands due to dewetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultrathin conjugated polymer layers. Here, LangmuirShafer-manufactured homogenous mono-and multilayers of semiconducting polymers on metal electrodes are reported and the energy level bending using photoelectron spectroscopy is tracked. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. These findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultrathin semiconducting polymers.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2016
National Category
Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering Biological Sciences
Identifiers
urn:nbn:se:liu:diva-126253 (URN)10.1002/adfm.201504729 (DOI)000371079300010 ()
Note

Funding Agencies|EU project SUNFLOWER of FP7 cooperation programme [287594]; Swedish Research Council [2013-4022]; Goran Gustafsson Foundation for Research in Natural Sciences and Medicine; Swedish Research Council Linnaeus grant LiLi-NFM; Advanced Functional Materials Center at Linkoping University

Available from: 2016-03-21 Created: 2016-03-21 Last updated: 2017-11-30
Kesters, J., Govaerts, S., Pirotte, G., Drijkoningen, J., Chevrier, M., Van den Brande, N., . . . Maes, W. (2016). High-Permittivity Conjugated Polyelectrolyte Interlayers for High-Performance Bulk Heterojunction Organic Solar Cells. ACS Applied Materials and Interfaces, 8(10), 6309-6314
Open this publication in new window or tab >>High-Permittivity Conjugated Polyelectrolyte Interlayers for High-Performance Bulk Heterojunction Organic Solar Cells
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2016 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 10, p. 6309-6314Article in journal (Refereed) Published
Abstract [en]

Conjugated polyelectrolyte (CPE) interfacial layers present a powerful way to boost the I-V characteristics of organic photovoltaics. Nevertheless, clear guidelines with respect to the structure of high-performance interlayers are still lacking. In this work, impedance spectroscopy is applied to probe the dielectric permittivity of a series of polythiophene-based CPEs. The presence of ionic pendant groups grants the formation of a capacitive double layer, boosting the charge extraction and device efficiency. A counteracting effect is the diminishing affinity with the underlying photoactive layer. To balance these two effects, we found copolymer structures containing nonionic side chains to be beneficial.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2016
Keyword
organic photovoltaics; cathode interlayers; conjugated polyelectrolytes; impedance spectroscopy; dielectric permittivity
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-127270 (URN)10.1021/acsami.6b00242 (DOI)000372479300002 ()26927416 (PubMedID)
Note

Funding Agencies|IAP project Functional Supramolecular Systems [7/05]; Science Policy Office of the Belgian Federal Government (BELSPO); Research Program of the Research Foundation Flanders (FWO) [G.0415.14N]; Foundation for Fundamental Research on Matter (FOM) from The Netherlands Organization for Scientific Research (NWO) [V0714M-13MV60]; Swedish Research Council Linnaeus LiLi-NFM at Linkoping University; Vrije Universiteit Brussel (VUB); University of Montpellier; CNRS; University of Mons

Available from: 2016-04-20 Created: 2016-04-19 Last updated: 2017-11-01
Gaceur, M., Ben Dkhil, S., Duche, D., Bencheikh, F., Simon, J.-J., Escoubas, L., . . . Ackermann, J. (2016). Ligand-Free Synthesis of Aluminum-Doped Zinc Oxide Nanocrystals and their Use as Optical Spacers in Color-Tuned Highly Efficient Organic Solar Cells. Advanced Functional Materials, 26(2), 243-253
Open this publication in new window or tab >>Ligand-Free Synthesis of Aluminum-Doped Zinc Oxide Nanocrystals and their Use as Optical Spacers in Color-Tuned Highly Efficient Organic Solar Cells
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2016 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 2, p. 243-253Article in journal (Refereed) Published
Abstract [en]

The color of polymer solar cells using an opaque electrode is given by the reflected light, which depends on the composition and thickness of each layer of the device. Metal-oxide-based optical spacers are intensively studied in polymer solar cells aiming to optimize the light absorption. However, the low conductivity of materials such as ZnO and TiO2 limits the thickness of such optical spacers to tenths of nanometers. A novel synthesis route of cluster-free Al-doped ZnO (AZO) nanocrystals (NCs) is presented for solution processing of highly conductive layers without the need of temperature annealing, including thick optical spacers on top of polymer blends. The processing of 80 nm thick optical spacers based on AZO nanocrystal solutions on top of 200 nm thick polymer blend layer is demonstrated leading to improved photocurrent density of 17% compared to solar cells using standard active layers of 90 nm in combination with thin ZnO-based optical spacers. These AZO NCs also open new opportunities for the processing of high-efficiency color tuned solar cells. For the first time, it is shown that applying solution-processed thick optical spacer with polymer blends of different thicknesses can process solar cells of similar efficiency over 7% but of different colors.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2016
Keyword
azo; interfacial layers; nanocrystals; organic solar cells; zinc oxide
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-124634 (URN)10.1002/adfm.201502929 (DOI)000368041200009 ()
Note

Funding Agencies|EU [FP7-ICT-2011-7, 287594]; SFUMATO-FUI Project [AAP12]; Generalitat Valenciana (Project Institute of Nanotechnologies for Clean Energies) [ISIC/2012/008]

Available from: 2016-02-09 Created: 2016-02-08 Last updated: 2017-11-30
del Pozo, F. G., Fabiano, S., Pfattner, R., Georgakopoulos, S., Galindo, S., Liu, X., . . . Mas-Torrent, M. (2016). Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors. Advanced Functional Materials, 26(14), 2379-2386
Open this publication in new window or tab >>Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors
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2016 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 14, p. 2379-2386Article in journal (Refereed) Published
Abstract [en]

In electronics, the field-effect transistor (FET) is a crucial cornerstone and successful integration of this semiconductor device into circuit applications requires stable and ideal electrical characteristics over a wide range of temperatures and environments. Solution processing, using printing or coating techniques, has been explored to manufacture organic field-effect transistors (OFET) on flexible carriers, enabling radically novel electronics applications. Ideal electrical characteristics, in organic materials, are typically only found in single crystals. Tiresome growth and manipulation of these hamper practical production of flexible OFETs circuits. To date, neither devices nor any circuits, based on solution-processed OFETs, has exhibited an ideal set of characteristics similar or better than todays FET technology based on amorphous silicon. Here, bar-assisted meniscus shearing of dibenzo-tetrathiafulvalene to coat-process self-organized crystalline organic semiconducting domains with high reproducibility is reported. Including these coatings as the channel in OFETs, electric field and temperature-independent charge carrier mobility and no bias stress effects are observed. Furthermore, record-high gain in OFET inverters and exceptional operational stability in both air and water are measured.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keyword
Organic field-effect transistors, thin-film coating, charge carrier mobility
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Physical Sciences
Identifiers
urn:nbn:se:liu:diva-127774 (URN)10.1002/adfm.201502274 (DOI)000374258100014 ()
Note

Funding Agencies|ERC [StG 2012-306826]; Networking Research Center on Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN); DGI (Spain) [BE-WELL CTQ2013-40480-R]; Generalitat de Catalunya [2014-SGR-17]; Advanced Functional Materials Center at Linkoping University; Onnesjo Foundation; Knut and Alice Wallenberg Foundation; Swedish Foundation for Strategic Research (SSF); Universidad Tecnica de Ambato; Secretaria de Educacion Superior, Ciencia, Tecnologia e Innovacion

Available from: 2016-05-12 Created: 2016-05-12 Last updated: 2017-11-30
Malti, A., Brooke, R., Liu, X., Zhao, D., Andersson Ersman, P., Fahlman, M., . . . Crispin, X. (2015). A substrate-free electrochromic device.
Open this publication in new window or tab >>A substrate-free electrochromic device
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Electrochromic displays based on conducting polymers offer higher contrast, are cheaper, faster, more durable, and easier to synthesize as well as to process than their non-polymeric counterparts. The field of organic electrochromics has made considerable strides in the last decade with the development of new materials and methods. Here, we present a cellulose composite combining PEDOT:PSS and TiO2 that is a free-standing electrochromic material. Owing to the excellent refractive properties of TiO2, this nanocomposite is white in the neutral state and, when reduced, turns blue resulting in a color contrast exceeding 30. The composite has a granular morphology and, as shown by AFM, an intermingling of TiO2 and PEDOT:PSS at the surface. Variation of TiO2 within the material led to a trade-off in optical and electrical properties. A proof of concept free-standing electrochromic device was fabricated by casting several layers, which was found to be stable over 100 cycles.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122020 (URN)
Available from: 2015-10-16 Created: 2015-10-16 Last updated: 2017-02-03Bibliographically approved
Ullah Khan, Z., Bubnova, O., Jafari, M. J., Brooke, R., Liu, X., Gabrielsson, R., . . . Crispin, X. (2015). Acido-basic control of the thermoelectric properties of poly(3,4-ethylenedioxythiophene)tosylate (PEDOT-Tos) thin films. Journal of Materials Chemistry C, 3, 10616-10623
Open this publication in new window or tab >>Acido-basic control of the thermoelectric properties of poly(3,4-ethylenedioxythiophene)tosylate (PEDOT-Tos) thin films
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2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, p. 10616-10623Article in journal (Refereed) Published
Abstract [en]

PEDOT-Tos is one of the conducting polymers that displays the most promising thermoelectric properties. Until now, it has been utterly difficult to control all the synthesis parameters and the morphology governing the thermoelectric properties. To improve our understanding of this material, we study the variation in the thermoelectric properties by a simple acido-basic treatment. The emphasis of this study is to elucidate the chemical changes induced by acid (HCl) or base (NaOH) treatment in PEDOT-Tos thin films using various spectroscopic and structural techniques. We could identify changes in the nanoscale morphology due to anion exchange between tosylate and Cl- or OH-. But, we identified that changing the pH leads to a tuning of the oxidation level of the polymer, which can explain the changes in thermoelectric properties. Hence, a simple acid-base treatment allows finding the optimum for the power factor in PEDOT-Tos thin films.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Polymer Chemistry Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:liu:diva-121977 (URN)10.1039/C5TC01952D (DOI)000363251600035 ()
Note

Funding agencies: European Research Council (ERC) [307596]

Available from: 2015-10-14 Created: 2015-10-14 Last updated: 2018-02-13Bibliographically approved
Shi, S., Gao, F., Sun, Z., Zhan, Y., Fahlman, M. & Ma, D. (2015). Effects of side groups on the kinetics of charge carrier recombination in dye molecule-doped multilayer organic light-emitting diodes. Journal of Materials Chemistry C, 3(1), 46-50
Open this publication in new window or tab >>Effects of side groups on the kinetics of charge carrier recombination in dye molecule-doped multilayer organic light-emitting diodes
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2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 1, p. 46-50Article in journal (Refereed) Published
Abstract [en]

The carrier recombination coefficient (gamma) in dye molecule-doped multilayer organic light-emitting diodes was quantified by transient electroluminescence. It was found that gamma and device efficiency were both strongly dependent on the molecular structures of the dopants.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Physical Sciences Biological Sciences
Identifiers
urn:nbn:se:liu:diva-113156 (URN)10.1039/c4tc02414a (DOI)000345920500009 ()
Note

Funding Agencies|Hundreds Talents Program, Chinese Academy of Sciences; National Science Fund for Distinguished Young Scholars of China [50325312]; European Commission

Available from: 2015-01-14 Created: 2015-01-12 Last updated: 2017-12-05
Malti, A., Edberg, J., Granberg, H., Khan, Z. U., Andreasen, J. W., Liu, X., . . . Berggren, M. (2015). Enabling organic power electronics with a cellulose nano-scaffold.
Open this publication in new window or tab >>Enabling organic power electronics with a cellulose nano-scaffold
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Exploiting the nanoscale properties of certain materials enables the creation of new materials with a unique set of properties. Here, we report on an electronic (and ionic) conducting paper based on cellulose nanofibrils (CNF) composited with poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS), which may be facilely processed into large three-dimensional geometries, while keeping unprecedented electronic and ionic conductivities of 140 S/cm and 20 mS/cm, respectively. This is achieved by cladding the CNF with PEDOT:PSS, and trapping an ion-transporting phase in the interstices between these nanofibrils. The unique properties of the resulting nanopaper composite have been used to demonstrate (electrochemical) transistors, supercapacitors and conductors resulting in exceptionally high device parameters, such as an associated transconductance, charge storage capacity and current level beyond 1 S, 1 F and 1 A, respectively.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-122021 (URN)
Available from: 2015-10-16 Created: 2015-10-16 Last updated: 2018-02-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9879-3915

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