Dissociation of Frenkel Excitons at the Interface between a Molecular Crystal and a Metal

Abstract

AbstractThe first part of the paper deals with the non‐radiative decay modes of n π* triplet excitons at the interface between a p‐chloranil crystal and an aluminum contact studied by means of extrinsic photocurrents. Utilizing the technique of inserting fatty acid mono‐layers between crystal and metal, which allows variation of the interaction distance, it is shown (i) that the dominant exciton decay process is a fast charge transfer reaction and (ii) that its rate constant decreases exponentially with increasing reaction distance. In the second part of the paper a model is presented to treat exciton dissociation processes at a metal surface in general. It is based on the concept of configuration interaction between the bound molecular exciton state and a continuum of ionized states.