Neighboring‐Cation Substitution Engineering Strategy toward High Performance in Near‐Infrared Light Source for Multifunctional Applications

Abstract Efficient broadband near‐infrared (NIR)‐emitting phosphors with long‐wavelength emission peaks and high thermal stability are urgently needed as next‐generation smart NIR light sources. However, considerable challenges remain in developing high‐performing NIR phosphors. Herein, a blue LED excitable Bi 1.8 Ga 1.2 SbO 7 : Cr 3+ (BGS: Cr 3+ ) phosphor with a broad emission band and a long emission peak is designed and synthesized. Further, a strategy of neighboring‐cation substitution engineering is proposed to improve the efficiency and thermal stability of the phosphor. The optimal phosphor (BGS: 0.02Cr 3+ , 0.8In 3+ ) can generate an NIR emission in the 700–1300 nm range with a full‐width at half‐maximum (FWHM) of 198 nm. This phosphor has an external quantum efficiency (EQE) of 31.3% and a good thermal stability of 56.1% at 423 K. A fabricated NIR‐LED device can achieve an NIR output power of 125.55 mW at 300 mA and a photoelectric efficiency of 17.45% at 20 mA, demonstrating its considerable application potential for night vision, bioimaging and nondestructive detection. This study offers new thoughts to fulfill NIR phosphors with outstanding luminescent performances.