An Introduction to Electrogenerated Chemiluminescence

Chapter 14 illustrates the fundamentals of electrogenerated chemiluminescence (ECL), i.e. the process in which species generated at an electrode surface spontaneously undergo electron-transfer reactions able to generate light-emitting excited states. The conditions required to observe ECL emission, as well as the feasible pathways for generating photons, have been reviewed by a basic and simple approach. Concepts like quantum efficiency and ECL quantum efficiency are introduced and discussed. Two main ECL mechanisms are illustrated: annihilation and co-reactant pathways. The use of co-reactant and its role is discussed, in particular the interaction of tripropylamine with [Ru(bpy)3]2+, the most widely employed co-reactant and luminophore system for ECL measurements. fig2: Basic setup for ECL measurements. PMT=photomultiplier tube.fig3: (a) Cyclic voltammogram and (b) ECL emission of an aqueous solution (pH 8) containing [Ru(bpy)3]2+ and TPA in a ratio of about nm : m; scan rate 0.05 V s−1.