Enhancement effect of photoluminescence in assemblies of nano-ZnO particles silica aerogels

SiO2 aerogels were prepared by a sol-gel method and supercritical drying. Introduction of nano-ZnO into nanopores of the SiO2 aerogels is performed by immersion, chemical reaction, and hydrolysis. Photoluminescence of these assemblies of nano-ZnO particles/SiO2 aerogels were systematically measured. For each assembly, a very strong photoluminescence (PL) band with the peak position of about 500 nm was observed. The luminescence intensities of the assemblies of nano-ZnO particles/SiO2 aerogels are 10-50 times higher than that of nanostructured ZnO bulks. The quantum efficiency of the PL band for the assemblies is in the range of 0.2%-1%. This luminescence enhancement effect is caused by the increase of the singly ionized oxygen vacancies in nano-ZnO particles, which are located in nanopores of the SiO2 aerogel. (C) 1998 American Institute of Physics.