Energy transfer and enhanced luminescence in metal oxide nanoparticle and rare earth codoped silica

Abstract

A significant enhancement of photoluminescence from ${\mathrm{Eu}}^{3+}$ embedded in $\mathrm{Si}{\mathrm{O}}_2$ matrix is observed by codoping with wide band-gap ${\mathrm{In}}_2{\mathrm{O}}_3$ nanoparticles. The enhanced photoluminescence characteristics are strongly influenced by the postannealing temperature and the ${\mathrm{In}}^{3+}$ concentration. Synchronous scanning photoluminescence technique was used to understand the excitation and luminescence behavior in codoped silica films. Based on the experimental results, we argue that the enhancement of photoluminescence is associated with the effective energy transfer process from ${\mathrm{In}}_2{\mathrm{O}}_3$ nanoparticles to the charge transfer band of ${\mathrm{O}}^{2+}–{\mathrm{Eu}}^{3+}$ instead of the direct transfer to the rare-earth energy levels.