Jump to main content
Jump to site search


Electronic couplings and rates of excited state charge transfer processes at poly(thiophene-co-quinoxaline)–PC71BM interfaces: two- versus multi-state treatments

Author affiliations

Abstract

Electronic coupling between adjacent molecules is one of the key parameters determining the charge transfer (CT) rates in bulk heterojunction (BHJ) polymer solar cells (PSCs). We calculate theoretically electronic couplings for exciton dissociation (ED) and charge recombination (CR) processes at local poly(thiophene-co-quinoxaline) (TQ)–PC71BM interfaces. We use eigenstate-based coupling schemes, i.e. the generalized Mulliken–Hush (GMH) and fragment charge difference (FCD) schemes, including 2 to multiple (3–11) states. Moreover, we study the effects of functionals, excited state methods, basis sets, surrounding media, and relative placements of TQ and PC71BM on the coupling values. Generally, both schemes provide consistent couplings with the global hybrid functionals, which yield more charge-localized diabatic states and constant coupling values regardless of the number of states, and so the 2-state schemes may be sufficient. The (non-tuned and optimally tuned) long-range corrected (LRC) functionals result in more notable mixing of the local components with the CT states. Employing multiple states reduces the mixing and thus improves the LRC results, although the method still affects the GMH CR couplings. As the FCD scheme is less sensitive, we recommend combining it with the multi-state treatment for polymer–fullerene systems when using the LRC functionals. Finally, we employ the 11-state FCD couplings to calculate the ED and CR rates, which are consistent with the experimental rates of the polymer–fullerene systems. Our results provide more insight into choosing a suitable eigenstate-based coupling scheme for predicting the electronic couplings and CT rates in photoactive systems.

Graphical abstract: Electronic couplings and rates of excited state charge transfer processes at poly(thiophene-co-quinoxaline)–PC71BM interfaces: two- versus multi-state treatments

Back to tab navigation

Supplementary files

Publication details

The article was received on 31 Aug 2019, accepted on 31 Oct 2019 and first published on 01 Nov 2019


Article type: Paper
DOI: 10.1039/C9CP04837E
Phys. Chem. Chem. Phys., 2019, Advance Article
  • Open access: Creative Commons BY-NC license
  •   Request permissions

    Electronic couplings and rates of excited state charge transfer processes at poly(thiophene-co-quinoxaline)–PC71BM interfaces: two- versus multi-state treatments

    T. Kastinen, D. A. da Silva Filho, L. Paunonen, M. Linares, L. A. Ribeiro Junior, O. Cramariuc and T. I. Hukka, Phys. Chem. Chem. Phys., 2019, Advance Article , DOI: 10.1039/C9CP04837E

    This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material and it is not used for commercial purposes.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements