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.