Photoisomerization-coupled electron transfer

TL;DR

This paper explores a theoretical model for ultrafast electron transfer triggered by photoisomerization in photochromic molecules, revealing their inseparable nature and potential for controlled light-switchable electronic applications.

Contribution

It introduces a unified theoretical framework for understanding photoisomerization-coupled electron transfer in molecular systems, supported by DFT calculations.

Findings

Electron transfer and photoisomerization are inseparable processes.

Theoretical model predicts ultrafast electron transfer during photoisomerization.

Control strategies for transfer efficiency are discussed.

Abstract

Photochromic molecular structures constitute a unique platform for constructing molecular switches, sensors and memory devices. One of their most promising applications is as light-switchable electron acceptor or donor units. Here, we investigate a previously unexplored process that we postulate may occur in such systems: an ultrafast electron transfer triggered by a simultaneous photoisomerization of the donor or the acceptor moiety. We propose a theoretical model for this phenomenon and, with the aid of DFT calculations, apply it to the case of a dihydropyrene-type photochromic molecular donor. By considering the wavepacket dynamics and the photoisomerization yield, we show that the two processes involved, electron transfer and photoisomerization, are in general inseparable and need to be treated in a unified manner. We finish by discussing how the efficiency of photoisomerization-coupled electron transfer can be controlled experimentally.