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

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 degrees 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.