Fe ³⁺ ‐Activated Near‐Infrared Mechanoluminescence in Double Perovskite Compound

Abstract Near‐infrared mechanoluminescence (NIR ML) materials, owing to the unique force‐to‐light conversion characteristics, have attracted considerable attention, such as in bioimaging and structural health monitoring fields. However, current NIR ML materials are limited to a restricted selection of activators, which significantly hinders their practical applications. Herein, a series of Fe 3+ ‐activated double perovskite broadband emission NIR MLs are prepared (A 2 BB'O 6 :Fe 3+ ). Among them, Sr 2 ScSbO 6 :Fe 3+ has broadband NIR ML covering 800–1000 nm at a low activation threshold ≈1 N, while maintaining strong emission and reasonably stable cycling performance even at 573 K. Thermoluminescence measurements and density‐functional‐theory calculations identify the defect type and distribution of Sr 2 ScSbO 6 :Fe 3+ . The host exhibits a continuous distribution of shallow‐to‐deep defects (0.02–0.97 eV). These defects efficiently quench persistent luminescence and ambient‐light interference, enabling a robust NIR ML noise‐signal ratio. In addition, such NIR ML emission has bio tissue penetration ability, showing potential bio stress‐related application imaging prospects.