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

ABSTRACT 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 NaLnS ₂ : Cr ³⁺ (Ln = Lu, Y, Gd), peaking at 980, 1020, and 1080 nm, respectively. Notably, NaLuS ₂ : Cr ³⁺ 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 NaGdS ₂ : Cr ³⁺ . 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.