Role of Li+ on white light emission from Sm3+ and Tb3+ co-doped Y2O3 nano-phosphor

Abstract

This paper reports on white light emission from Sm3+ and Tb3+ co-doped Y2O3 nano-phosphor, synthesized through the solution combustion method. The XRD and TEM measurements of the nano-phosphors reveal a crystalline nature and spherical particle distribution. The Sm3+-doped nano-phosphor gives off an orange-red emission whereas the Tb3+-doped nano-phosphor gives off blue and green emissions individually on excitation with 380 nm radiation. When the Sm3+and Tb3+ ions are doped together, the co-doped nano-phosphor emits white light with the CIE coordinates 0.33 and 0.37, due to the combined emissions of these two ions on excitation with 380 nm radiation. The color of the emitted light is tunable with the concentration of Sm3+ ions, and it emits white light at the 2.0 mol% concentration of Sm3+ and 1.0 mol% concentration of Tb3+ ions. The nano-phosphor sample annealed at a higher temperature results in a greater emission intensity. The presence of Li+ ions in the co-doped sample enhances the emission intensity of white light up to three times. The enhancement in the emission intensity is discussed in terms of a reduction in the optical quenching centers and an increase in the crystallite size. The Sm3+ and Tb3+ co-doped Y2O3 nano-phosphor in the presence of Li+ is a suitable candidate for white light in a solid state display.