Ultra‐Bright Far‐Red Tribo‐Mechanoluminescent Composite Based on Work‐Function‐Mediated Charge Transfer and Dielectric Polarization for Human‐Machine Interfaces

Tribo‐mechanoluminescence (Tribo‐ML) is a promising technology for wearable human‐machine interfaces (HMIs), leveraging its self‐powered operation, mechanical compliance, and inherent strain sensitivity. However, practical adoption has been hindered by high activation thresholds and an incomplete mechanistic understanding of its mechano‐electro‐optical conversion pathway. Here, an inorganic‐polymer composite film (Tb 3 Sc 2 Al 3 O 12 : Eu 3+ @PDMS) is designed to harness interfacial triboelectrification, delivering mechanical compliance and an ultra‐bright far‐red Tribo‐ML emission at 711 nm. The composite achieves an ultrahigh triboelectric charge density (TECD) of 17.5 nC/cm 2 under an ultralow activation of 1 N at 1 Hz. A DFT‐validated, work‐function‐modulated triboelectric charge‐transfer mechanism is established, enabling the ultra‐high TECD (17.5 nC/cm 2 ) when the work‐function difference between the phosphor and PDMS reaches 1.11 eV. By integrating the Dielectric Theory of Chemical Bonds for Complex Crystals with the Clausius‐Mossotti relation, a quantitative link is established between the macroscopic dielectric constant ( ε r ) and microscopic polarization characteristics, revealing that ε r is regulated by polarizability and exhibits a positive correlation with it. When integrated into the HMIs, the 711 nm emission exhibits minimal signal crosstalk during underwater transmission, highlighting its environmental robustness. These findings clarify the mechano‐to‐photon conversion pathway in Tribo‐ML systems and offer practical design principles for next‐generation intelligent wearable devices.