A Super Stable Near-Infrared Garnet Phosphor Resistant to Thermal Quenching, Thermal Degradation and Hydrolysis

Abstract

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 phosphor Y 3 (Al,Mg) 2 (Al,Si) 3 O 12 :Cr 3+ (YMAS:Cr 3+ ) by substitution via 2[Al 3+ ]→[Mg 2+ ]+[Si 4+ ] based on prototype Y 3 Al 5 O 12 :Cr 3+ . The YMAS:Cr 3+ 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 4 T 2 → 4 A 2 transition of Cr 3+ in YMAS:Cr 3+ , and the higher efficiency and broadening emission spectra compared to the prototype Y 3 Al 5 O 12 :Cr 3+ (QY = 16%) of spin-forbidden 2 E → 4 A 2 in the strong crystal field. Potential applications are demonstrated by using YMAS:Cr 3+ 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.

Keywords: Near-Infrared Light, Thermal Stability, Chemical Stability, DFT calculations