High-Efficiency Short-Wave Infrared Emitter Enabled by Cr3+–Yb3+ Co-Doped Phosphor

The utilization of phosphor-converted light-emitting diodes (pc-LEDs) as compact short-wave infrared (SWIR) emitters has emerged as a promising strategy for miniature SWIR spectrometers in portable devices, enabling diverse applications such as nondestructive identification, bioimaging, night-vision surveillance, and optical communication. However, discovering phosphors capable of efficiently absorbing blue light and emitting pure SWIR light (>900 nm) remains a significant challenge. Here, highly efficient and thermally stable SWIR luminescence of Yb 3+ upon blue LED excitation by employing Cr 3+ –Yb 3+ energy transfer in Y 3 Ga 5 O 12 garnet is reported. The prepared Y 3 Ga 5 O 12 :Cr 3+ ,Yb 3+ phosphor exhibits intense SWIR emission spanning from 900 to 1150 nm at 438 nm excitation, coupled with ultra-high internal/external quantum efficiency of 80.8%/40.2% and excellent luminescence thermal stability (108%@150 °C). A SWIR pc-LED prototype fabricated by incorporating the optimized phosphor with a commercial 450 nm blue LED chip, shows exceptional SWIR luminescence performance, delivering a SWIR output power of 92.7 mW at a driving current of 350 mA and a photoelectric efficiency of 21.5% at 10 mA. This work opens up a new avenue for designing SWIR phosphors that exhibit efficient and thermally stable photoluminescence with blue LED excitation, demonstrating significant potential for next-generation high-power compact SWIR light sources.