A super stable Near-Infrared garnet phosphor resistant to thermal Quenching, thermal degradation and hydrolysis

Near-infrared (NIR) light-emitting materials are crucial for night vision, in vivo-imaging, and secret codes. However, issues such as thermal quenching and chemical stability tend to significantly suppress the efficiency. In this work, we modify NIR-emitting phosphor Y3(Al,Mg)2(Al,Si)3O12:Cr3+ (YMAS:Cr3+) by substitution via 2[Al3+] → [Mg2+] + [Si4+] based on prototype Y3Al5O12:Cr3+. The YMAS:Cr3+ phosphor shows extraordinary optical performance and chemical stability, with 86–93% quantum yield (QY), 94% room temperature emission intensity at 150 °C, and almost no luminescent loss after 8 days in water and heating at 1000 °C. The substitution lifts the local symmetry, leading to a weak crystal field, spin-allowed 4T2→4A2 transition of Cr3+ in YMAS:Cr3+, and the higher efficiency and broadening emission spectra compared to the prototype Y3Al5O12:Cr3+ (QY = 16%) of spin-forbidden 2E→4A2 in the strong crystal field. Potential applications are demonstrated by using YMAS:Cr3+ in a high-power output light-emitting diode and luminescent ink. This work proposes the strategy via altering the local effect for improving luminescence properties, potentially stimulating further research on NIR-emitting materials.