Boosting near-infrared photoluminescence efficiency of erbium ions and ZnO quantum dots codoped amorphous silica thin films

Abstract

Er3+ ions and ZnO QDs codoped amorphous silica thin films are prepared by the modified sol-gel spin-coating technique. By introducing the ZnO QDs as sensitizers, the PL emission intensity of Er3+ ions is enhanced by more than two orders of magnitude. With the increasing annealing temperature, the lengthening PL emission lifetime indicates the gradual passivation of the non-radiative trap states. The thermal quenching behavior of PL emission intensity is analyzed by the temperature-dependent PL spectra. With the increasing annealing temperature, the decrease of activation energy suggests the narrowing of energy level difference between the excited state of Er3+ ions and the defect state of ZnO QDs. The gradually improved phonon-assisted energy transfer efficiency results in the greatly enhanced PL efficiency of Er3+ ions. These results will be a starting point for further research on the sensitization mechanisms in the rare earth ions and wide-bandgap QDs codoped amorphous silica.