Strategies to approach high performance in Cr^(3+)-doped phosphors for high-power NIR-LED light sources

摘要

Broadband near-infrared(NIR)-emitting phosphors are key for next-generation smart NIR light sources based on blue LEDs.To achieve excellent NIR phosphors,we propose a strategy of enhancing the crystallinity,modifying the micromorphology,and maintaining the valence state of Cr^(3+) in Ca_(3)Sc_(2)Si_(3)O_(12) garnet(CSSG).By adding fluxes and sintering in a reducing atmosphere,the internal quantum efficiency(IQE)is greatly enhanced to 92.3%.The optimized CSSG:6% Cr^(3+) exhibits excellent thermal stability.At 150℃,97.4% of the NIR emission at room temperature can be maintained.The fabricated NIR-LED device emits a high optical power of 109.9mW at 520 mA.The performances of both the achieved phosphor and the NIR-LED are almost the best results until now.The mechanism for the optimization is investigated.An application of the NIR-LED light source is demonstrated.