Tunable photoluminescence from YTaO4: Bi3+ for ultraviolet converted pc-WLED with high chromatic stability

摘要： To avoid the color drift of WLED at high temperature, it is significant to develop color stable luminescent materials. Herein we report on a phosphor YTaO4:Bi3+ with a stable blue emission upon ultraviolet excitations even as the temperature changes between 300 and 480 K. Upon excitations into host absorptions a tunable blue emission can be led from 400 nm to 450 nm due to the enhanced energy transfer efficiency from host to bismuth ions as the concentration of bismuth increases. As excitation scheme is modulated between 355 and 370 nm the white emission can be achieved in the compound of YTaO4 single doped with Bi3+, which has rarely been reported previously. For proof of concept the prototype WLEDs have been demonstrated with the phosphor YTaO4:Bi3+ and the 365 nm InGaN chips under different driving currents. Our findings make it possible for single phase white emitting phosphors activated by a single ion of Bi3+ for WLEDs, and also can inspire to develop WLED devices with high chromatic stability.