Fine‐Tuning of Near‐Infrared Emission in Fe‐Activated Spinel Phosphors via the Synergistic Effect of Sites Inversion and Atomic Disorder

Abstract Achieving continuous tunability, high efficiency, and outstanding thermal stability of near‐infrared (NIR) phosphors remains challenging for optoelectronic device fields. To address this issue, a strategy is proposed based on the substitution of both cations and anions in the intermediate spinel structure, which successfully achieved fine‐tuning of NIR emission of Mg 1+y Ga 2‐y O 4‐y F y :Fe 3+ phosphors with prominent optical characteristics. The NIR emission contains new luminescent centers with random O/F coordination and is successfully constructed. This co‐substitution promotes further inversion of the cationic sites and induces atomic disorder, changing the crystal coordination environment and making Fe 3+ breakthrough the Laporte selection rule, enabling fine‐tuning of Fe 3+ emissions in the range of 707–740 nm and broadening of the full width at half maximum by 30 nm. Moreover, the Mg 1.15 Ga 1.85 O 3.85 F 0.15 :Fe 3+ phosphor reached a high quantum yield of 71.6% and presented excellent thermal stability with an emission intensity retention of 81% at 493 K. The emission of the fabricated NIR phosphor‐converted light‐emitting diodes also matched well with the photosensitive pigment P fr , demonstrating its feasibility for plant growth lighting applications.