Next-Generation Short-Wave Infrared LED Phosphors Based on Chromium Doped Rare Earth Sulfides

External quantum efficiency (EQE) and thermal stability of phosphors are two critical parameters for next-generation short-wave infrared (SWIR) phosphor-converted light-emitting devices (pc-LEDs). However, it remains a significant challenge to develop SWIR-emitting phosphors that simultaneously exhibit high EQE and excellent thermal stability. Here, by leveraging the strong covalency, low phonon energy and structural symmetry of sulfides, we successfully realize high-performance tunable SWIR emission in sulfide phosphors NaLnS₂: Cr³⁺ (Ln = Lu, Y, Gd), peaking at 980, 1020, and 1080 nm, respectively. Notably, NaLuS₂: Cr³⁺ simultaneously achieves a record - high EQE of 61.55% along with superior thermal stability, while an EQE of 48.55% is also demonstrated at 1080 nm in NaGdS₂: Cr³⁺. The corresponding SWIR pc-LED delivers a high SWIR output power of 169.2 mW@350 mA, significantly outperforming the commercial devices. Finally, advanced palm vein recognition and portable non-destructive detection are successfully demonstrated. This study provides new insights and an effective materials platform for developing high-performance SWIR-emitting materials toward advanced photonic applications.