Superior Quantum Efficiency Blue‐Emitting Phosphors with High Thermal Stability toward Multipurpose LED Applications

Abstract Since Bi³⁺‐activated phosphor are widely reported in phosphors‐converted light‐emitting diodes (pc‐LEDs), developing new‐high efficiency phosphors is imperative. Herein, superior internal quantum efficiency (IQE = 93.7%) and external quantum efficiency (EQE = 70.5%) are achieved with blue‐emitting gallate phosphor CaGdGaO₄:Bi³⁺. Particularly, the photoluminescence excitation (PLE) spectrum ranges from 200 to 400 nm with two peaks at 337 and 368 nm, which match well with the 365 nm near ultraviolet (n‐UV) chip. The blue emission is attributed to two luminescence centers caused by Bi³⁺ occupying GdO₆ and CaO₆ sites. Furthermore, the thermal stability (@ 150 °C) enhanced from 73.2% to 80.1% when Ca²⁺ doping. A white LED (WLED) with high color rendering index (Ra) of 93.8 is prepared by as‐synthesized phosphors, indicating the potential application in WLED. The blue and red dual‐emitting phosphors are achieved by co‐doping Bi³⁺ and Eu³⁺. Finally, the rice planting experiment presents that the blue‐emitting can efficiently enhance the photosynthesis and seeding index of rice, which indicated these phosphors have significance in plant fill light.