Yellow phosphors coated with TiO2 for the enhancement of photoluminescence and thermal stability

In order to improve the phosphor efficiency of yellow emission of the phosphor-converted white light emitting diode (pcW-LED), the Ba2+ Mg2+ co-doped Sr2SiO4:Eu phosphors were synthesized and were coated with thin and uniform TiO2. The TiO2 layer with 20 nm was uniformly coated over the phosphor surface. The photoluminescence (PL) properties of the TiO2-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 TiO2-coated phosphors showed superior thermal quenching property compared to pristine phosphors. We concluded that the TiO2-coated surface of the phosphor is an effective way to improve the phosphor efficiency and enhance the thermal quenching stability.