Optical tuning and energy transfer of single-phase white-emitting Y3TaO7:Bi3+, Eu3+ for ultraviolet converted pc-WLED with high chromatic stability

Reabsorption and color drift at high temperature hinder the high-quality application of the phosphor-converted white light-emitting diodes (pc-WLEDs) devices, thus it is urgent to develop the single-phase white-emitting phosphors with good chromatic stability. In this work, a series of color-tunable Y 3 TaO 7 :Bi 3+ , Eu 3+ phosphors are designed by co-doping Bi 3+ and Eu 3+ based on the crystal structure information and energy transfer principle between Bi 3+ and Eu 3+ , which can be adjusted to achieve single-phase white emission. By increasing the temperature to a high value of 473 K, the emission peak of Bi 3+ ions still present at 470 nm in Y 3 TaO 7 :Bi 3+ phosphors even when the concentration of Bi 3+ ions changes, and the characteristic emission peaks of Bi 3+ and Eu 3+ basically maintain unchanged throughout in Y 3 TaO 7 :Bi 3+ , Eu 3+ phosphors. Finally, the single-phased Y 3 TaO 7 :0.025Bi 3+ , 0.06Eu 3+ phosphor was employed with ultraviolet chip to produce a warm WLED device with color rendering index of 81.5, correlated color temperature of 4165 K and the Commission International de I′Eclairage chromaticity coordinates of (0.3645, 0.3347). The results indicate that Y 3 TaO 7 :Bi 3+ , Eu 3+ phosphors with high chromaticity stability have great application potential in full-spectrum WLEDs.