Synergy between Defects and Lattice Distortion Drives Self‐Powered Elastico‐Near‐Infrared Mechanoluminescence in Cr ³⁺ ‐Doped Spinel Oxides

Abstract Elastico‐mechanoluminescence (ML) enables unique force‐to‐light transduction for applications in human‐machine interaction and smart sensing, yet traditional trap‐controlled models fail to explain self‐powered ML phenomena. Here, a Cr ³⁺ ‐doped spinel oxide exhibiting autonomous near‐infrared (NIR) ML is reported, where self‐powered emission originates from synergistic interactions between local lattice distortions and multi‐defect networks. Theoretical calculations reveal that Cr ³⁺ doping activates nearest‐neighbor sites to generate mid‐gap states, facilitating stress‐driven electron tunneling to luminescent centers without external excitation. The material shows narrowband NIR emission (711 nm) from the spin‐forbidden transition, with linear ML intensity response to mechanical stress and negligible persistent luminescence. Proof‐of‐concept demonstrations in bright‐field anti‐counterfeiting (NIR QR‐code imaging) and biomedical tissue penetration (10 mm pork) validate its practical utility. This work establishes a defect‐distortion coupling mechanism for self‐powered NIR‐ML, providing a theoretical framework to guide the design of next‐generation autonomous optomechanical materials for energy‐efficient sensing and bio‐imaging.