Enhanced Thermally Stability and Broadened Emission for Gd ₃ Ga ₅ O ₁₂ :Cr ³⁺ Phosphors via Si ₃ N ₄ Substitution

Abstract 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 Si 3 N 4 ‐substitution strategy is employed to regulate the luminescence of Gd 3 Ga 5 O 12 :Cr 3+ (GGG:Cr 3+ ) phosphors. The bandwidth of GGG:Cr 3+ is 95 nm, and then it is broadened to 116 nm due to the Si 3 N 4 ‐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 Si 3 N 4 ‐free sample. The intensity of the optimal specimen is elevated 2.9 times compared with the Si 3 N 4 ‐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.