Reorganization asymmetry of electron transfer in ferroelectric media and principles of artificial photosynthesis

Abstract

This study considers electronic transitions within donor-acceptor complexes dissolved in media with macroscopic polarization. The change of the polarizability of the donor-acceptor complex in the course of electronic transition couples to the reaction field of the polar environment and the electric field created by the macroscopic polarization. An analytical theory developed to describe this situation predicts a significant asymmetry of the reorganization energy between charge separation and charge recombination transitions. This result is proved by Monte Carlo simulations of a model polarizable diatomic dissolved in a ferroelectric fluid of soft dipolar spheres. The ratio of the reorganization energies for the forward and backward reactions up to a factor of 25 is obtained in the simulations. This result, as well as the effect of the macroscopic electric field, is discussed in application to the design of efficient photosynthetic devices.