Synergistic Optimization Between Chromium Local Coordination States Toward Self‐Powered High‐Repeatability Near‐Infrared Mechanoluminescence

Abstract Self‐powered mechanoluminescence (S‐ML) elastomer with near‐infrared (NIR) emission exhibits great potential for the next generation of bio‐imaging, bio‐sensing, and human‐machine interaction fields. However, due to the lack of understanding of the mechanical‐photon conversion mechanism, the emission efficiency and cycling stability of ML materials reported so far are still unable to meet the application needs. Herein, high‐repeatability (>10000 times) and tunable near‐infrared (650–1000 nm) mechanoluminescent materials are reported by optimizing Cr 3+ local coordination states in a simple centrosymmetric MgO host. The constructed electron transfer model among multiple Cr 3+ ion states (isolated Cr 3+ , Cr 3+ pair, and Cr 3+ cluster) reveals the structure‐activity relationship between local piezoelectricity and photoelectric output. Theoretical calculations and experimental results reveal that the heterovalent substitution of Cr 3+ ions promotes the [MgO 6 ] distortion to activate the nearest neighboring defect to form suitable intermediate gap states, facilitating stress‐driven electron tunneling to Cr 3+ states. Proof‐of‐concept multi‐layered bright field sensing and imaging is developed with all‐round interactive NIR tactile perception. This work not only provides a high‐repeatability NIR ML phosphor but also establishes the integrated thinking mode for material‐performance‐device rational design.