Effect of Y3+ codoping on luminescence decays of the 4I13/2 level in Er3+-doped Al2O3 powders prepared by a sol-gel method

Abstract

The luminescence lifetime of the 0.01 mol.%-0.1 mol.% Er3+- and 0–20 mol.% Y3+-codoped Al2O3 powders prepared at a sintering temperature of 900°C in a non-aqueous sol-gel method has been investigated to explore the enhanced mechanism of photoluminescence properties of the Er3+-doped Al2O3 by Y3+ codoping. For the 0.1 mol.% Er3+-Y3+-codoped Al2O3 powders, the measured lifetime of Er3+ gradually increases with increasing Y3+ concentration. Consequently, codoping with 20 mol.% Y3+ leads to an increase in the measured lifetime from 3.5 to 5.8 ms. By comparing the measured lifetime for different Er3+ concentrations in the Al2O3 powders, the radiative lifetime of both the Er3+-doped and the Er3+-Y3+-codoped Al2O3 powders is estimated to be about 7.5 ms. Infrared absorption spectra indicate that Y3+ codoping does not change the-OH content in the Er3+-Y3+-codoped Al2O3 powders. The prolonged luminescence lifetime of the 4I13/2 level of Er3+ in Er3+-doped Al2O3 powders by Y3+ codoping is ascribed to the decrease in the energy transfer rate between the Er3+ ions and the Er3+ and -OH, respectively, due to the suppressed interaction between Er3+ ions.