Print Email Facebook Twitter Quasi-one dimensional in-plane conductivity in filamentary films of PEDOT:PSS Title Quasi-one dimensional in-plane conductivity in filamentary films of PEDOT:PSS Author van de Ruit, K. Cohen, R.I. Bollen, D. van Mol, T. Yerushalmi-Rozen, R. Janssen, R.A.J. Kemerink, M. Publication year 2013 Abstract The mechanism and magnitude of the in-plane conductivity of poly(3,4-ethy-lenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films is determined using temperature dependent conductivity measurements for various PEDOT:PSS weight ratios with and without a high boiling solvent (HBS). Without the HBS the in-plane conductivity of PEDOT:PSS is lower and for all studied weight ratios well described by the relation σ = σexp-(T0T) 0.5] with T0 a characteristic temperature. The exponent 0.5 indicates quasi-one dimensional (quasi-1D) variable range hopping (VRH). The conductivity prefactor σ0 varies over three orders of magnitudes and follows a power law σ0a∝c 3.5 PEDOT with cPEDOT the weight fraction of PEDOT in PEDOT:PSS. The field dependent conductivity is consistent with quasi-1D VRH. Combined, these observations suggest that conductance takes place via a percolating network of quasi-1D filaments. Using transmission electron microscopy (TEM) filamentary structures are observed in vitrified dispersions and dried films. For PEDOT:PSS films with HBS, the conductivity also exhibits quasi-1D VRH behavior when the temperature is less than 200 K. The low characteristic temperature T0 indicates that HBS-treated films are close to the critical regime between a metal and an insulator. In this case, the conductivity prefactor scales linearly with cPEDOT, indicating the conduction is no longer limited by a percolation of filaments. The lack of observable changes in TEM upon processing with the HBS suggests that the changes in conductivity are due to a smaller spread in the conductivities of individual filaments, or a higher probability for neighboring filaments to be connected rather than being caused by major morphological modification of the material. In-plane conductivity in PEDOT:PSS takes place via filaments. This conclusion is based on charge transport measurements that indicate quasi-one dimensional variable range hopping and is supported by transmission electron microscopy. At higher PEDOT to PSS ratios the number of connected filaments drastically increases, causing an orders of magnitude increase in conductivity, in good agreement with percolation theory. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Subject Mechatronics, Mechanics & MaterialsHOL - HolstTS - Technical SciencesHigh Tech Systems & MaterialsMaterialsIndustrial InnovationCharge transportConducting polymersOrganic electronicsCharacteristic temperatureField dependent conductivityMorphological modificationOrganic electronicsTemperature-dependent conductivityThree orders of magnitudeTransport measurementsVariable-range hoppingCharge transferSolventsTransmission electron microscopyConducting polymers To reference this document use: http://resolver.tudelft.nl/uuid:b947589a-bbc4-4134-ae50-8937829f819b DOI https://doi.org/10.1002/adfm.201301174 TNO identifier 485654 ISSN 1616-301X Source Advanced Functional Materials, 23 (46), 5778-5786 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.