Simultaneous Broadening and Enhancement of Cr³⁺ Photoluminescence in LiIn₂SbO₆ by Chemical Unit Cosubstitution: Night-Vision and Near-Infrared Spectroscopy Detection Applications

Near-infrared (NIR)-emitting phosphor materials have been extensively developed for optoelectronic and biomedical applications. Although Cr³⁺-activated phosphors have been widely reported, it is challenging to achieve ultra-broad and tunable NIR emission. Here, a new ultra-broadband NIR-emitting LiIn₂SbO₆:Cr³⁺ phosphor with emission peak at 965 nm and a full-width at half maximum of 217 nm is reported. Controllable emission tuning from 965 to 892 nm is achieved by chemical unit cosubstitution of [Zn²⁺–Zn²⁺] for [Li⁺–In³⁺], which can be ascribed to the upshift of ⁴T_2g energy level due to the strengthened crystal field. Moreover, the emission is greatly enhanced, and the FWHM reaches 235 nm. The as-prepared luminescent tunable NIR-emitting phosphors have demonstrated the potential in night-vision and NIR spectroscopy techniques. This work proves the feasibility of chemical unit cosubstitution strategy in emission tuning of Cr³⁺-doped phosphors, which can stimulate further studies on the emission-tunable NIR-emitting phosphor materials.