Yellow phosphors coated with TiO 2 for the enhancement of photoluminescence and thermal stability

Abstract

In order to improve the phosphor efficiency of yellow emission of the phosphor-converted white light emitting diode (pcW-LED), the Ba 2+ Mg 2+ co-doped Sr 2SiO 4:Eu phosphors were synthesized and were coated with thin and uniform TiO 2. The TiO 2 layer with 20 nm was uniformly coated over the phosphor surface. The photoluminescence (PL) properties of the TiO 2-coated phosphors showed improved yellow-emission intensity compared to the pristine phosphors. The temperature dependence of photoluminescence was measured from 25 to 150 °C. The TiO 2-coated phosphors showed superior thermal quenching property compared to pristine phosphors. We concluded that the TiO 2-coated surface of the phosphor is an effective way to improve the phosphor efficiency and enhance the thermal quenching stability.