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

## TL;DR

A new material generates infrared light through various mechanical forces, enabling durable underwater communication.

## Contribution

First self-recoverable mechanoluminescent material responsive to multiple forces with stable performance over 4,000 cycles.

## Key findings

- MgNb2O6:Cr3+ crystals produce SWIR emission via piezoelectric and triboelectric effects.
- Material shows stable ML signals over 4,000 stretching cycles in the SWIR range.
- Enables reliable underwater communication through multimodal mechanical responsiveness.

## Abstract

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.

This study represents the first demonstration of self‐recoverable mechanoluminescent (ML) within a single material across diverse mechanical modes, enabled by the synergistic coupling of piezoelectric and triboelectric effects. Through a combinatorial doping approach, the MgNb2O6 crystal exhibits breakthrough short‐wavelength infrared ML performance. Notably, the composite elastomer delivers stable ML over 4 000 stretching cycles, thereby enabling reliable underwater communication.