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 Y3TaO7:Bi3+, Eu3+ phosphors are designed by co-doping Bi3+ and Eu3+ based on the crystal structure information and energy transfer principle between Bi3+ and Eu3+, 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 Bi3+ ions still present at 470 nm in Y3TaO7:Bi3+ phosphors even when the concentration of Bi3+ ions changes, and the characteristic emission peaks of Bi3+ and Eu3+ basically maintain unchanged throughout in Y3TaO7:Bi3+, Eu3+ phosphors. Finally, the single-phased Y3TaO7:0.025Bi3+, 0.06Eu3+ 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 Y3TaO7:Bi3+, Eu3+ phosphors with high chromaticity stability have great application potential in full-spectrum WLEDs.