Quantum Efficiency of Electrochemiluminescence Generation by Tris(2,2’‐bipyridine)ruthenium(II) and Tri‐n‐propylamine Revisited from a Kinetic Reaction Model

Abstract

AbstractElectrochemiluminescence quantum efficiency (ECL‐QE) is an important parameter to evaluate the energy conversion ability of luminophores and analytical sensitivity of corresponding ECL systems. Herein, taking tris(2,2’‐bipyridine)ruthenium(II) (Ru(bpy)32+) and tri‐n‐propylamine (TPrA) coreactant system as an example, the ECL‐QE was evaluated in terms of a kinetic reaction model, in which Ru(bpy)33+ was considered to be the key intermediate in a reaction scheme consisting of competitive oxidative reduction and catalytic reaction routes. It was calculated as the product of electrochemical excitation efficiency (ηex) and light emission efficiency (i. e., photoluminescence quantum yield, PLQY). We used finite element simulations to examine the variation of ηex with the electrode material, applied potential, concentration and distance from the electrode surface. ηex was found to be largely determined by the electrochemical oxidation rate of TPrA that varied by several orders of magnitude with the electrode material. The estimation of ECL‐QE helped in selecting the appropriate conditions for efficient ECL generation and sensitive analysis.