Enhanced Thermally Stability and Broadened Emission for Gd3Ga5O12:Cr3+ Phosphors via Si3N4 Substitution

Far-red (FR) and near-infrared (NIR) spectroscopy technologies have attracted extensive attention. How to obtain luminescent materials suitable to FR-NIR phosphor-converted light-emitting diodes (pc-LEDs) is a crucial challenge. Herein, a Si3N4-substitution strategy is employed to regulate the luminescence of Gd3Ga5O12:Cr3+ (GGG:Cr3+) phosphors. The bandwidth of GGG:Cr3+ is 95 nm, and then it is broadened to 116 nm due to the Si3N4-substitution. Furthermore, at 423 K the thermal stability is enhanced to 98.7% of that at room temperature, which is higher than the reported 92.7%@423 K for the Si3N4-free sample. The intensity of the optimal specimen is elevated 2.9 times compared with the Si3N4-free sample sintered at the same condition. The FR pc-LED is manufactured by using the optimized sample, and its FR output power is 47.1 mW with a conversion efficiency of 15.9% driven by 100 mA. This work paves a new way to design high-performance NIR phosphors.