Structure tailoring and defect engineering of a highly thermally stable red emitting phosphor

Abstract

Phosphor-converted white light-emitting diodes (pc-WLEDs) are highly efficient light sources for lighting displays and electronic devices. To facilitate the development of next-generation high-power WLEDs, it is crucial to investigate more efficient red-emitting phosphors. One of the biggest challenges facing pc-LEDs is thermal quenching, in which phosphors suffer emission losses as the temperature rises during high-power LED operation. Here, we report a red phosphor Gd_3−yCa_y−0.02GaO₆:0.02Eu²⁺ (y = 0.2) with an emission center located at 650 nm and a half-peak width of 68 nm. At 423 K, the emission intensity can still maintain more than 95% of that at room temperature, which is owing to the defect level of the phosphor compensating for the emission loss. A white LED device was fabricated by combining a 460 nm blue LED chip and commercial yellow phosphor Y₃Al₅O₁₂:Ce³⁺ and Gd_3−yCa_y−0.02GaO₆:0.02Eu²⁺ (y = 0.2). The white LED has excellent properties with the correlated color temperature CCT = 3999 K and color rendering index Ra = 95, which demonstrates that the red phosphor Gd_3−yCa_y−0.02GaO₆:0.02Eu²⁺ (y = 0.2) has good application prospects in the field of white LEDs.