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General rule for the energy of water-induced traps in organic semiconductors

Abstract

Charge carrier traps are generally highly detrimental for the performance of semiconductor devices. Unlike the situation for inorganic semiconductors, detailed knowledge about the characteristics and causes of traps in organic semiconductors is still very limited. Here, we accurately determine hole and electron trap energies for a wide range of organic semiconductors in thin-film form. We find that electron and hole trap energies follow a similar empirical rule and lie ~0.3–0.4 eV above the highest occupied molecular orbital and below the lowest unoccupied molecular orbital, respectively. Combining experimental and theoretical methods, the origin of the traps is shown to be a dielectric effect of water penetrating nanovoids in the organic semiconductor thin film. We also propose a solvent-annealing method to remove water-related traps from the materials investigated, irrespective of their energy levels. These findings represent a step towards the realization of trap-free organic semiconductor thin films.

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Fig. 1: Analysis of current–voltage characteristics.
Fig. 2: Current–voltage characteristics of hole-only devices.
Fig. 3: Electron and hole trap energies.
Fig. 4: Impact of thermal and solvent treatment on traps.
Fig. 5: Evolution of IP and EA with water nanodroplet size.

Data availability

The data that support the findings of this study are available from the corresponding author on reasonable request.

Code availability

The code for the drift–diffusion simulation software is available from the corresponding author on reasonable request.

References

  1. 1.

    Nielsen, C. B., Holliday, S., Chen, H.-Y., Cryer, S. J. & McCulloch, I. Non-fullerene electron acceptors for use in organic solar cells. Acc. Chem. Res. 48, 2803–2812 (2015).

    CAS  Article  Google Scholar 

  2. 2.

    Grimsdale, A. C., Leok Chan, K., Martin, R. E., Jokisz, P. G. & Holmes, A. B. Synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Chem. Rev. 109, 897–1091 (2009).

    CAS  Article  Google Scholar 

  3. 3.

    van Reenen, S. & Kemerink, M. in Light-Emitting Electrochemical Cells (ed. Costa, R.) 3–45 (Springer, 2017).

  4. 4.

    Zhao, Y., Guo, Y. & Liu, Y. Recent advances in n-type and ambipolar organic field-effect transistors. Adv. Mater. 25, 5372–5391 (2013).

    CAS  Article  Google Scholar 

  5. 5.

    Asadi, K., Li, M., Blom, P. W. M., Kemerink, M. & de Leeuw, D. M. Organic ferroelectric opto-electronic memories. Mater. Today 14, 592–599 (2011).

    CAS  Article  Google Scholar 

  6. 6.

    Torsi, L. et al. A sensitivity-enhanced field-effect chiral sensor. Nat. Mater. 7, 412–417 (2008).

    CAS  Article  Google Scholar 

  7. 7.

    Abbaszadeh, D. et al. Elimination of charge carrier trapping in diluted semiconductors. Nat. Mater. 15, 628–633 (2016).

    CAS  Article  Google Scholar 

  8. 8.

    Mandoc, M. M., de Boer, B., Paasch, G. & Blom, P. W. M. Trap-limited electron transport in disordered semiconducting polymers. Phys. Rev. B 75, 193202 (2007).

    Article  Google Scholar 

  9. 9.

    Nicolai, H. T. et al. Unification of trap-limited electron transport in semiconducting polymers. Nat. Mater. 11, 882–887 (2012).

    CAS  Article  Google Scholar 

  10. 10.

    Nikolka, M. et al. High operational and environmental stability of high-mobility conjugated polymer field-effect transistors through the use of molecular additives. Nat. Mater. 16, 356–362 (2017).

    CAS  Article  Google Scholar 

  11. 11.

    Sinninghaus, H. Reliability of organic field‐effect transistors. Adv. Mater. 21, 3859–3873 (2009).

    Article  Google Scholar 

  12. 12.

    Mandoc, M. M., Kooistra, F. B., Hummelen, J. C., de Boer, B. & Blom, P. W. M. Effect of traps on the performance of bulk heterojunction organic solar cells. Appl. Phys. Lett. 91, 263505 (2007).

    Article  Google Scholar 

  13. 13.

    Blakesley, J. C. & Neher, D. Relationship between energetic disorder and open-circuit voltage in bulk heterojunction organic solar cells. Phys. Rev. B 84, 075210 (2011).

    Article  Google Scholar 

  14. 14.

    Dittmer, J. J., Marseglia, E. A. & Friend, R. H. Electron trapping in dye/polymer blend photovoltaic cells. Adv. Mater. 12, 1270–1274 (2000).

    CAS  Article  Google Scholar 

  15. 15.

    Shao, Y., Xiao, Z., Bi, C., Yuan, Y. & Huang, J. Origin and elimination of photocurrent hysteresis by fullerene passivation in CH3NH3PbI3 planar heterojunction solar cells. Nat. Commun. 5, 5784 (2014).

    CAS  Article  Google Scholar 

  16. 16.

    Zhang, Y., de Boer, B. & Blom, P. W. M. Trap-free electron transport in poly(p-phenylene vinylene) by deactivation of traps with n-type doping. Phys. Rev. B 81, 085201 (2010).

    Article  Google Scholar 

  17. 17.

    Tsai, M.-J. & Meng, H.-F. Electron traps in organic light-emitting diodes. J. Appl. Phys. 97, 114502 (2005).

    Article  Google Scholar 

  18. 18.

    Kuik Martijn et al. Charge transport and recombination in polymer light‐emitting diodes. Adv. Mater. 26, 512–531 (2014).

    CAS  Article  Google Scholar 

  19. 19.

    Kuik, M., Koster, L. J. A., Wetzelaer, G. A. H. & Blom, P. W. M. Trap-assisted recombination in disordered organic semiconductors. Phys. Rev. Lett. 107, 256805 (2011).

    CAS  Article  Google Scholar 

  20. 20.

    Wetzelaer, G. A. H., Kuik, M., Nicolai, H. T. & Blom, P. W. M. Trap-assisted and Langevin-type recombination in organic light-emitting diodes. Phys. Rev. B 83, 165204 (2011).

    Article  Google Scholar 

  21. 21.

    Street, R. A., Schoendorf, M., Roy, A. & Lee, J. H. Interface state recombination in organic solar cells. Phys. Rev. B 81, 205307 (2010).

    Article  Google Scholar 

  22. 22.

    Cowan, S. R., Roy, A. & Heeger, A. J. Recombination in polymer–fullerene bulk heterojunction solar cells. Phys. Rev. B 82, 245207 (2010).

    Article  Google Scholar 

  23. 23.

    Graupner, W., Leditzky, G., Leising, G. & Scherf, U. Shallow and deep traps in conjugated polymers of high intrachain order. Phys. Rev. B 54, 7610–7613 (1996).

    CAS  Article  Google Scholar 

  24. 24.

    Meier, M., Karg, S., Zuleeg, K., Brütting, W. & Schwoerer, M. Determination of trapping parameters in poly(p-phenylenevinylene) light-emitting devices using thermally stimulated currents. J. Appl. Phys. 84, 87–92 (1998).

    CAS  Article  Google Scholar 

  25. 25.

    P. Nikiforov, M. et al. Detection and role of trace impurities in high-performance organic solar cells. Energy Environ. Sci. 6, 1513–1520 (2013).

    Article  Google Scholar 

  26. 26.

    de Leeuw, D. M., Simenon, M. M. J., Brown, A. R. & Einerhand, R. E. F. Stability of n-type doped conducting polymers and consequences for polymeric microelectronic devices. Synth. Met. 87, 53–59 (1997).

    Article  Google Scholar 

  27. 27.

    Gomes, H. L., Stallinga, P., Cölle, M., de Leeuw, D. M. & Biscarini, F. Electrical instabilities in organic semiconductors caused by trapped supercooled water. Appl. Phys. Lett. 88, 082101 (2006).

    Article  Google Scholar 

  28. 28.

    Huang, J., Xu, Z. & Yang, Y. Low-work-function surface formed by solution-processed and thermally deposited nanoscale layers of cesium carbonate. Adv. Funct. Mater. 17, 1966–1973 (2007).

    CAS  Article  Google Scholar 

  29. 29.

    Zuo, G. et al. Molecular doping and trap filling in organic semiconductor host–guest systems. J. Phys. Chem. C 121, 7767–7775 (2017).

    CAS  Article  Google Scholar 

  30. 30.

    Felekidis, N., Melianas, A. & Kemerink, M. Automated open-source software for charge transport analysis in single-carrier organic semiconductor diodes. Org. Electron. 61, 318–328 (2018).

    CAS  Article  Google Scholar 

  31. 31.

    Mark, P. & Helfrich, W. Space‐charge‐limited currents in organic crystals. J. Appl. Phys. 33, 205–215 (1962).

    CAS  Article  Google Scholar 

  32. 32.

    Pasveer, W. F. et al. Unified description of charge-carrier mobilities in disordered semiconducting polymers. Phys. Rev. Lett. 94, 206601 (2005).

    CAS  Article  Google Scholar 

  33. 33.

    Nicolai, H. T., Mandoc, M. M. & Blom, P. W. M. Electron traps in semiconducting polymers: exponential versus Gaussian trap distribution. Phys. Rev. B 83, 195204 (2011).

    Article  Google Scholar 

  34. 34.

    Paasch, G. & Scheinert, S. Charge carrier density of organics with Gaussian density of states: analytical approximation for the Gauss–Fermi integral. J. Appl. Phys. 107, 104501 (2010).

    Article  Google Scholar 

  35. 35.

    van der Holst, J. J. M. et al. Modeling and analysis of the three-dimensional current density in sandwich-type single-carrier devices of disordered organic semiconductors. Phys. Rev. B 79, 085203 (2009).

    Article  Google Scholar 

  36. 36.

    Zuo, G., Li, Z., Wang, E. & Kemerink, M. High Seebeck coefficient and power factor in n-type organic thermoelectrics. Adv. Electron. Mater. 4, 1700501 (2017).

    Article  Google Scholar 

  37. 37.

    Melianas, A. et al. Photogenerated carrier mobility significantly exceeds injected carrier mobility in organic solar cells. Adv. Energy Mater. 7, 1602143 (2017).

    Article  Google Scholar 

  38. 38.

    Frisch, M. J. et al. Gaussian 09, Revision D.01 (Gaussian, 2009).

  39. 39.

    Berendsen, H. J. C., van der Spoel, D. & van Drunen, R. GROMACS: a message-passing parallel molecular dynamics implementation. Comput. Phys. Commun. 91, 43–56 (1995).

    CAS  Article  Google Scholar 

  40. 40.

    Lindahl, E., Hess, B. & van der Spoel, D. GROMACS 3.0: a package for molecular simulation and trajectory analysis. Mol. Model. Annu. 7, 306–317 (2001).

    CAS  Article  Google Scholar 

  41. 41.

    Spoel, D. V. D. et al. GROMACS: fast, flexible and free. J. Comput. Chem. 26, 1701–1718 (2005).

    Article  Google Scholar 

  42. 42.

    Jorgensen, W. L. & Tirado-Rives, J. The OPLS (optimized potentials for liquid simulations) potential functions for proteins, energy minimizations for crystals of cyclic peptides and crambin. J. Am. Chem. Soc. 110, 1657–1666 (1988).

    CAS  Article  Google Scholar 

  43. 43.

    Jorgensen, W. L., Maxwell, D. S. & Tirado-Rives, J. Development and testing of the OPLS all-atom force field on conformational energetics and properties of organic liquids. J. Am. Chem. Soc. 118, 11225–11236 (1996).

    CAS  Article  Google Scholar 

  44. 44.

    Berendsen, H. J. C., Postma, J. P. M., van Gunsteren, W. F., DiNola, A. & Haak, J. R. Molecular dynamics with coupling to an external bath. J. Chem. Phys. 81, 3684–3690 (1984).

    CAS  Article  Google Scholar 

  45. 45.

    DALTON: A Molecular Electronic Structure Program, Release DALTON2013.0 (Dalton, 2013); http://daltonprogram.org/

  46. 46.

    Aidas, K. et al. The Dalton quantum chemistry program system. WIRES Comput. Mol. Sci. 4, 269–284 (2014).

    CAS  Article  Google Scholar 

  47. 47.

    Yanai, T., Tew, D. P. & Handy, N. C. A new hybrid exchange–correlation functional using the Coulomb-attenuating method (CAM-B3LYP). Chem. Phys. Lett. 393, 51–57 (2004).

    CAS  Article  Google Scholar 

  48. 48.

    Kendall, R. A., Dunning, T. H. & Harrison, R. J. Electron affinities of the first‐row atoms revisited. Systematic basis sets and wave functions. J. Chem. Phys. 96, 6796–6806 (1992).

    CAS  Article  Google Scholar 

  49. 49.

    Woon, D. E. & Dunning, T. H. Gaussian basis sets for use in correlated molecular calculations. III. The atoms aluminum through argon. J. Chem. Phys. 98, 1358–1371 (1993).

    CAS  Article  Google Scholar 

  50. 50.

    Ahlström, P., Wallqvist, A., Engström, S. & Jönsson, B. A molecular dynamics study of polarizable water. Mol. Phys. 68, 563–581 (1989).

    Article  Google Scholar 

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Acknowledgements

The research by G.Z. was supported by the Chinese Scholarship Council (CSC). M.L. thanks SeRC (Swedish e-Science Research Center) for funding and SNIC (Swedish National Infrastructure for Computing) for computing resources (SNIC 2018/3-554).

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G.Z. constructed all devices and performed and analysed all experiments. M.L. performed DFT and QM/MM simulations. T.U. performed the processing conditions study. M.K. wrote the drift–diffusion simulation software, conceived the idea and coordinated research. G.Z. and M.K. wrote the manuscript with input from M.L.

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Correspondence to Martijn Kemerink.

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Supplementary Information

Section 1: full names and chemical structures. Section 2: effects of built-in voltage and injection barriers. Section 3: insensitivity to transport parameters. Section 4: J–V curves of hole-only devices not shown in the main text. Section 5: J–V curves of electron-only devices. Section 6: DFT calculations. Section 7: QM/MM calculations. Section 8: role of processing conditions.

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Zuo, G., Linares, M., Upreti, T. et al. General rule for the energy of water-induced traps in organic semiconductors. Nat. Mater. 18, 588–593 (2019). https://doi.org/10.1038/s41563-019-0347-y

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