Influences of doping and annealing conditions on the photoluminescence from In2O3 nanocrystals and Eu3+ ions co-doped sol-gel SiO2 films

Abstract

In2O3 nanocrystals and rare-earth Eu3+ ions co-doped SiO2 films were prepared by sol-gel method and subsequently annealed at high temperature to eliminate the hydroxyl groups. The formation of In2O3 nanocrystals with uniform distribution in the annealed sample was confirmed by transmission electron microscopy and x-ray diffraction spectra. A strong characteristic emission from Eu3+ ions can be identified and the influences of In and Eu doping concentrations on photoluminescence properties were systematically evaluated. It was found that the photoluminescence from Eu3+ ions could be enhanced by two orders of magnitude. This was ascribed to the effective absorption of incident photons by In2O3 nanocrystals, the energy transfer process through oxygen vacancy at the surface of In2O3 nanocrystals to nearby Eu3+ ions and the SiO2 matrix free of hydroxyl groups after high temperature annealing.