Electrogenerated Chemiluminescence : Kinetics and Mechanisms for Mixed System

Abstract

In this review, principle and experimental for electrogenerated chemiluminescence (ECL) are briefly introduced. ECL involves electrode reactions (heterogeneous electron transfer), diffusion, homogeneous electron transfer, formation of excited states, and emission process in solution. ECL behaviors are frequently discussed based on thermodynamics, i.e. , whether the emissive excited states can be formed via homogeneous electron transfer or not. Here, ECL mechanism in mixed system, which was revealed based on the homogeneous electron transfer process and electronic structure of several photoluminescent materials, are focused. It is demonstrated that kinetic analysis is useful to discuss the ECL efficiency quantitatively. The rate constant of the homogeneous electron transfer depends on the energy gap between the initial (a pair of oxidized and reduced forms of photoluminescence material) and final states (singlet and triplet excited states), and the gap can arbitrarily be controlled in a mixed ECL system, which contains coreactant systems.