Two Selective Sites Control of Cr3+‐Doped ABO4 Phosphors for Tuning Ultra‐Broadband Near‐Infrared Photoluminescence and Multi‐Applications

Abstract Achieving ultra‐broadband and tunable photoluminescence of near‐infrared (NIR) emitting phosphors is a key challenge for realizing its multi‐applications. Here, a series of new ABO 4 :Cr 3+` (A 3+ = Ga, Sc, In; B 5+ = Ta, Nb) NIR‐emitting phosphors with unprecedented tunable photoluminescence based on crystallographic site engineering and crystal field regulation is reported. Large spectral tuning from NIR‐I to NIR‐II is realized with the peak position varying from 825 to 1025 nm, by cation substitution with decreasing crystal field strength. Broadened full‐width at half maximum from 125 to 231 nm can be tailored by controlling the occupancy of Cr 3+ on two different sites. Potential multi‐applications of the tunable NIR emitting phosphors are proposed and validated in NIR spectroscopy detection, night vision, penetrating biology tissue, and so on. This work demonstrates that crystallographic site engineering can effectively tune the NIR optical properties of Cr 3+ ‐doped phosphor materials for multi‐photoelectric applications.