Charge transfer in molecular complexes with 2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane (F4-TCNQ): A density functional theory study

Lingyun Zhu, Eung Gun Kim*, Yuanping Yi, Jean-Luc Bredas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

80 Scopus citations

Abstract

Molecular doping is a charge-transfer process intended to improve the electrical properties of organic semiconductors and the efficiency of organic electronic devices, by incorporation of a complex-forming, strong molecular electron acceptor or donor. Using density functional theory methods with dispersion corrections, we seek to monitor charge transfer and estimate its amount via calculations of experimental observables. With 2,3,5,6-tetrafluoro-7, 7,8,8-tetracyanoquinodimethane (F4-TCNQ) as a p-dopant (electron acceptor) and an array of π-conjugated molecules as hole-transport materials (donors), the amount of charge transfer is seen to be a non-monotonic function of the offset defined by the donor ionization potential (IP) and the acceptor electron affinity (EA), IP - |EA|. Interestingly, a well-defined, linear relationship between the amount of charge transfer and IP - |EA| is obtained when the IP and EA values are adjusted to reflect intramolecular geometric changes in the final form of the complex. This study offers a straightforward way to match donor-acceptor pairs with desired doping effects and to estimate the resulting charge density in organic semiconductors.

Original languageEnglish (US)
Pages (from-to)5149-5159
Number of pages11
JournalChemistry of Materials
Volume23
Issue number23
DOIs
StatePublished - Dec 13 2011

Keywords

  • DFT
  • IP-EA offset
  • charge transfer
  • molecular complexes
  • molecular doping
  • organic semiconductors

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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