Boosting Near‐Infrared Emission in Spinel‐Type Phosphor via Oxygen Vacancy Engineering for Versatile Application

Abstract Fe 3+ ‐doped MgGa 2 O 4 (MGO: Fe 3+ ) spinel‐type near‐infrared (NIR) phosphor with non‐toxicity, outstanding thermal stability, and tunable emission has recently gained great concern owing to its wide applications. Nevertheless, the existence of detrimental O defects in the MgGa 2 O 4 host and the forbidden d‐d transitions of Fe 3+ lead to unsatisfactory luminescence efficiency, limiting the commercial application. In this study, a vacancy repairing engineering has been innovatively developed via F − substitution in MGO: Fe 3+ (MGOF: Fe 3+ ) for significantly enhancing NIR emission and maintaining outstanding thermal stability. Specifically, F − substitution with a similar radius effectively repairs the intrinsic O vacancy defects of MGO, thereby prohibiting the detrimental electron‐capturing effect. Meanwhile, F − incorporation can make the lattice of MGO distort and break the forbidden transition of Fe 3+ . Significantly, the obtained MGOF: Fe 3+ presents a 16‐fold higher emission intensity than that of MGO: Fe 3+ . More important, the MGOF: Fe 3+ can remain at 91.17% (363 K) and 85.10% (423 K). Finally, the NIR emission of MGOF: Fe 3+ can be used for night vision, non‐destructive biological tissue detection, and food analysis. The proposed vacancy repairing strategy can certainly stimulate some new thoughts and concepts in designing high‐performance phosphors for wider applications.