Effect of Y codoping on luminescence decays of the I level in Er-doped AlO 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 ⁴I_13/2 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.

Keywords

Er³⁺-doped Al₂O₃ / luminescence lifetime / Y³⁺ codoping / sol-gel method