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

A detailed analysis of the luminescence quantum efficiencies of nanocrystal line ZnO particles is presented in this paper. The influence of particle si ze on the quantum efficiency of the visible emission is studied. It is show n that the quantum efficiency of the visible emission decreases from 20% fo r particles with a mean radius of 7 Angstrom to 12% for particles with a me an radius of 10 Angstrom. An explanation for the size-dependence of the qua ntum efficiency is presented. This explanation is based on a model for the relaxation of a photoexcited ZnO particle that has been published previousl y. (C) 2001 Elsevier Science B.V. All rights reserved.