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Charge-transport model for conducting polymers

Abstract

The growing technological importance of conducting polymers makes the fundamental understanding of their charge transport extremely important for materials and process design. Various hopping and mobility edge transport mechanisms have been proposed, but their experimental verification is limited to poor conductors. Now that advanced organic and polymer semiconductors have shown high conductivity approaching that of metals, the transport mechanism should be discernible by modelling the transport like a semiconductor with a transport edge and a transport parameter s. Here we analyse the electrical conductivity and Seebeck coefficient together and determine that most polymers (except possibly PEDOT:tosylate) have s = 3 and thermally activated conductivity, whereas s = 1 and itinerant conductivity is typically found in crystalline semiconductors and metals. The different transport in polymers may result from the percolation of charge carriers from conducting ordered regions through poorly conducting disordered regions, consistent with what has been expected from structural studies.

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Figure 1: Schematic of the σE transport model and analysis procedure.
Figure 2: Percolation transport in polymers.
Figure 3: The thermopower versus electrical conductivity relation at room temperature, comparing various models.
Figure 4: Contour plot (dashed lines) of thermoelectric figure of merit zT (assuming κl = 0.2 W m−1 K−1 and T = 300 K).

References

  1. LeBlanc, S., Yee, S. K., Scullin, M. L., Dames, C. & Goodson, K. E. Material and manufacturing cost considerations for thermoelectrics. Renew. Sustain. Energy Rev. 32, 313–327 (2014).

    CAS  Article  Google Scholar 

  2. Yee, S. K. Thermoelectric Generators: a Material, Device, and Cost Perspective (2015 MRS Fall Meeting, 2015).

  3. Sirringhaus, H. 25th anniversary article: organic field-effect transistors: the path beyond amorphous silicon. Adv. Mater. 26, 1319–1335 (2014).

    CAS  Article  Google Scholar 

  4. Service, R. F. Outlook brightens for plastic solar cells. Science 332, 293 (2011).

    CAS  Article  Google Scholar 

  5. Green, M. A., Emery, K., Hishikawa, Y., Warta, W. & Dunlop, E. D. Solar cell efficiency tables (Version 45). Prog. Photovolt. Res. Appl. 23, 1–9 (2015).

    Article  Google Scholar 

  6. Malinkiewicz, O. et al. Perovskite solar cells employing organic charge-transport layers. Nat. Photon. 8, 128–132 (2014).

    CAS  Article  Google Scholar 

  7. Bubnova, O. et al. Optimization of the thermoelectric figure of merit in the conducting polymer poly(3,4-ethylenedioxythiophene). Nat. Mater. 10, 429–433 (2011).

    CAS  Article  Google Scholar 

  8. Kim, G. H., Shao, L., Zhang, K. & Pipe, K. P. Engineered doping of organic semiconductors for enhanced thermoelectric efficiency. Nat. Mater. 12, 719–723 (2013).

    CAS  Article  Google Scholar 

  9. Kang, K. et al. 2D coherent charge transport in highly ordered conducting polymers doped by solid state diffusion. Nat. Mater. (2016).

  10. Venkateshvaran, D. et al. Approaching disorder-free transport in high-mobility conjugated polymers. Nature 515, 384–388 (2014).

    CAS  Article  Google Scholar 

  11. Zhang, X. et al. Molecular origin of high field-effect mobility in an indacenodithiophene-benzothiadiazole copolymer. Nat. Commun. 4, 2238 (2013).

    Article  Google Scholar 

  12. Noriega, R. et al. A general relationship between disorder, aggregation and charge transport in conjugated polymers. Nat. Mater. 12, 1038–1044 (2013).

    CAS  Article  Google Scholar 

  13. Podzorov, V. Conjugated polymers: long and winding polymeric roads. Nat. Mater. 12, 947–948 (2013).

    CAS  Article  Google Scholar 

  14. Glaudell, A. M., Cochran, J. E., Patel, S. N. & Chabinyc, M. L. Impact of the doping method on conductivity and thermopower in semiconducting polythiophenes. Adv. Energy Mater. 5, 1401072 (2015).

    Article  Google Scholar 

  15. Mott, N. F. & Davis, E. A. Electronic Processes in Non-Crystalline Materials 2nd edn (Oxford Univ. Press, 1979).

    Google Scholar 

  16. Overhof, H. & Thomas, P. in Insulating and Semiconducting Glasses (ed. Boolchand, P.) 553–606 (World Scientific, 2000).

    Book  Google Scholar 

  17. Kaiser, A. B. Electronic transport properties of conducting polymers and carbon nanotubes. Rep. Prog. Phys. 64, 1–49 (2001).

    CAS  Article  Google Scholar 

  18. Bisquert, J. Interpretation of electron diffusion coefficient in organic and inorganic semiconductors with broad distributions of states. Phys. Chem. Chem. Phys. 10, 3175–3194 (2008).

    CAS  Article  Google Scholar 

  19. Shakouri, A. & Suquan, L. Eighteenth International Conference on Thermoelectrics 402–406 (IEEE, 1999).

    Google Scholar 

  20. Fistul, V. I. Heavily Doped SemiconductorsCh. 3 (Plenum Press, 1969).

    Google Scholar 

  21. Dohler, G. H. Conductivity, thermopower, and statistical shift in amorphous semiconductors. Phys. Rev. B 19, 2083–2091 (1979).

    Article  Google Scholar 

  22. Park, Y. W. Structure and morphology: relation to thermopower properties of conductive polymers. Synth. Met. 45, 173–182 (1991).

    CAS  Article  Google Scholar 

  23. Epstein, A. J. et al. Inhomogeneous disorder and the modified Drude metallic state of conducting polymers. Synth. Met. 65, 149–157 (1994).

    CAS  Article  Google Scholar 

  24. Wu, C.-G. & Chang, S.-S. Nanoscale measurements of conducting domains and current–voltage characteristics of chemically deposited polyaniline films. J. Phys. Chem. B 109, 825–832 (2005).

    CAS  Article  Google Scholar 

  25. Abeles, B., Pinch, H. L. & Gittleman, J. I. Percolation conductivity in W-Al2O3 granular metal films. Phys. Rev. Lett. 35, 247–250 (1975).

    CAS  Article  Google Scholar 

  26. Kirkpatrick, S. Percolation and conduction. Rev. Mod. Phys. 45, 574–588 (1973).

    Article  Google Scholar 

  27. Duong, D. T. et al. Mechanism of crystallization and implications for charge transport in poly(3-ethylhexylthiophene) thin films. Adv. Funct. Mater. 24, 4515–4521 (2014).

    CAS  Article  Google Scholar 

  28. Kim, B., Shin, H., Park, T., Lim, H. & Kim, E. NIR-sensitive poly(3,4-ethylenedioxyselenophene) derivatives for transparent photo-thermo-electric converters. Adv. Mater. 25, 5483–5489 (2013).

    CAS  Article  Google Scholar 

  29. Chang, W. B. et al. Electrochemical effects in thermoelectric polymers. ACS Macro Lett. 5, 455–459 (2016).

    CAS  Article  Google Scholar 

  30. Goldsmid, H. J. Introduction to ThermoelectricityCh. 4 (Springer, 2010).

    Book  Google Scholar 

  31. Lee, S. et al. Trap-limited and percolation conduction mechanisms in amorphous oxide semiconductor thin film transistors. Appl. Phys. Lett. 98, 203508 (2011).

    Article  Google Scholar 

  32. Grevin, B., Rannou, P., Payerne, R., Pron, A. & Travers, J. P. Scanning tunneling microscopy investigations of self-organized poly(3-hexylthiophene) two-dimensional polycrystals. Adv. Mater. 15, 881–884 (2003).

    CAS  Article  Google Scholar 

  33. Zhang, Q., Sun, Y., Xu, W. & Zhu, D. What to expect from conducting polymers on the playground of thermoelectricity: lessons learned from four high-mobility polymeric semiconductors. Macromolecules 47, 609–615 (2014).

    CAS  Article  Google Scholar 

  34. Sun, J. et al. Simultaneous increase in Seebeck coefficient and conductivity in a doped poly(alkylthiophene) blend with defined density of states. Macromolecules 43, 2897–2903 (2010).

    CAS  Article  Google Scholar 

  35. Xuan, Y. et al. Thermoelectric properties of conducting polymers: the case of poly(3-hexylthiophene). Phys. Rev. B 82, 115454 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

The authors thank H. Katz, M. L. Chabinyc, A. M. Glaudell and H.-S. Kim for valuable discussions and O.-Y. Choi for assistance in figure illustration. This work was supported by the AFOSR MURI programme under FA9550-12-1-0002.

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S.D.K. developed the ideas and theory for this work. S.D.K. and G.J.S. prepared and edited the manuscript.

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Correspondence to G. Jeffrey Snyder.

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Kang, S., Snyder, G. Charge-transport model for conducting polymers. Nature Mater 16, 252–257 (2017). https://doi.org/10.1038/nmat4784

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