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 Todd La Porte, Ryan Michael Young*, Tobin Jay Marks, Michael R Wasielewski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

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 (US)
JournalJournal of Porphyrins and Phthalocyanines
DOIs
StateAccepted/In press - Jan 1 2019

Keywords

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

ASJC Scopus subject areas

  • Chemistry(all)

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