The influence of particle size on the luminescence quantum efficiency of nanocrystalline ZnO particles

A detailed analysis of the luminescence quantum efficiencies of nanocrystalline ZnO particles is presented in this paper. The influence of particle size on the quantum efficiency of the visible emission is studied. It is shown that the quantum efficiency of the visible emission decreases from 20% for particles with a mean radius of 7 Å to 12% for particles with a mean radius of 10 Å. An explanation for the size-dependence of the quantum efficiency is presented. This explanation is based on a model for the relaxation of a photoexcited ZnO particle that has been published previously.