Plasmonic anchoring boosts mechanoluminescence via mechano–electro–optical cascade

Localized surface plasmon resonance has been extensively exploited to enhance photoluminescence and electroluminescence, yet its application to mechanoluminescence remains unrealized due to the metal-induced quenching-enhancement trade-off and irreversible interfacial delamination under cyclic strain. Here we report the first plasmonically enhanced ML elastomer via an in-situ reduction strategy that anchors ~ 70 nm Au nanoparticles directly onto ZnS:Cu phosphors through covalent Au–S bonds within a PDMS matrix. This interfacial architecture simultaneously passivates sulfur-vacancy quenching centers and confines the LSPR near-field within the carrier-detrapping zone, accelerating radiative recombination via the Purcell effect. Concurrently, the covalent Au–S dipole establishes an “electronic lock” that temporally gates carrier release, mitigating non-radiative losses. Au incorporation alone boosts ML brightness (~ 6-fold) and mechano–optical sensitivity (~ 5.5-fold). When integrated with Al 2 O 3 stress concentrators, a synergistic mechano–electro–opticall cascade achieves ~ 9-fold enhancement at 20 wt% phosphor loading, with exceptional cyclic stability (2.78% fluctuation over 600 cycles). This platform circumvents the long-standing quenching-durability dilemma, enabling self-powered strain mapping, wearable stress monitoring, and intuitive human-machine interfaces. Our work establishes a generalizable interfacial design paradigm for plasmon-enhanced mechanophotonic devices.