Photoinduced electron transfer from zinc meso -tetraphenylporphyrin to a one-dimensional perylenediimide aggregate: Probing anion delocalization effects

Joaquin M. Alzola, Natalia E. Powers-Riggs, Nathan T. La Porte, Ryan M. Young, Tobin J. Marks, Michael R. Wasielewski

Research output: Contribution to journalArticle

Abstract

Organic photovoltaics incorporating non-fullerene acceptors based on perylenediimide (PDI) now rival fullerene acceptor-based devices in performance, although the mechanisms of charge generation in PDI-based devices are not yet fully understood. Fullerene-based systems are proposed to undergo electron transfer directly from the photoexcited donor into a band of delocalized acceptor states, thus increasing charge generation efficiency. Similarly, anion delocalization has been shown to enhance the rate of electron transfer from a photoexcited donor to two electronically coupled PDI acceptors. Here we investigate how additional electron acceptors may further increase the rate of electron transfer from the donor zinc meso-tetraphenylporphyrin (ZnTPP) to an aggregate of PDI acceptors (PDI3). Femtosecond transient visible and mid-infrared absorption spectroscopies show that the rate of electron transfer from 1*ZnTPP to the PDI assembly ZnTPP2-PDI3 is statistically identical to that of the previously examined ZnTPP-PDI2. A Marcus theory analysis indicates that the parameters governing electron transfer are nearly identical for the two molecules, suggesting that the maximum electron transfer rate enhancement has been achieved in a cofacial PDI dimer because the ZnTPP directly couples to the first two PDI acceptors whereas the coupling to the third PDI is too weak.

Original languageEnglish
Pages (from-to)143-152
Number of pages10
JournalJournal of Porphyrins and Phthalocyanines
Volume24
Issue number1-3
DOIs
Publication statusPublished - Jan 1 2020

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Keywords

  • Marcus theory
  • charge separation
  • delocalization
  • density of states
  • electron transfer
  • meso- zinc tetraphenylporphyrin
  • organic photovoltaics
  • perylenediimide
  • transient absorption spectroscopy
  • transient infrared spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)

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