Multi‐Force‐Driven Self‐Recoverable SWIR Mechanoluminescence for Underwater Communication

Mechanoluminescence (ML) materials featuring photon emission by mechanical stimuli deliver sustainable solutions for frontier applications such as underwater communication. However, the practical utilization of current ML systems has been largely constrained by single-mode force responsiveness, low cyclic repeatability, and weak resistance to environmental interferences. Herein, we report a new class of MgNb₂O₆:Cr³⁺ crystals for the self-recoverable generation of short-wavelength infrared (SWIR) emission across multiple forms of mechanical action. Mechanistic investigations affirm the synergistic contribution of piezoelectric and triboelectric effects, thereby yielding high-brightness and cyclic-repeatable SWIR-ML under long-term mechanical loads. Strikingly, the coupling effect enables unprecedented stable ML signals over 4 000 continuous stretching cycles, which is hitherto inaccessible in the SWIR range. Our findings provide rational design guidelines for multimodal-force-driven self-recoverable and cyclically stable ML material systems, which raise new possibilities for reliable underwater communication technologies.