Self‐Charging Near‐Infrared Mechano‐Afterglow in Cr³⁺ Activated Composites

Near‐infrared mechanoluminescence (NIR‐ML) materials play critical roles in bio‐imaging, biomechanical sensing, etc. However, current NIR‐ML systems exhibit short ML lifetimes spanning nanoseconds to microseconds, which mandates a complex detection apparatus that exacerbates both technical demands and operational costs. To overcome these constraints, developing NIR‐ML materials with prolonged emission durations represents a promising solution. Herein, an elastic composite demonstrating exceptional NIR emission persistence exceeding 100 s post‐mechanical activation is developed, achieving notably self‐sustained luminescence without requiring pre‐excitation through light or other energy sources. Mechanistic investigations reveal that interfacial triboelectric effects during mechanical stimulation generate autonomous energy storage in material defects, thereby enabling sustained radiative recombination. The composite's application is experimentally verified in tissue‐mimicking biomechanical monitoring scenarios, with its dark‐field tracking potential demonstrated through NIR light visualization. This research not only advances a novel mechano‐afterglow composite but also proposes an energy‐storage‐driven design framework for next‐generation smart mechano‐optical materials.