Mechanoluminescence of ZnS Under Easily Tailored Phase Transitions

Mn/Cu-doped ZnS has emerged as a highly promising self-recoverable mechanoluminescent (ML) materials with significant potential in intelligent sensing, dynamic displays, and artificial intelligence. However, the exact ML mechanism remains elusive, and the energy transfer processes governed by complex interactions remain unknown. This study finds dislocation-mediated ML enhancement in ZnS:Mn and ML suppression in ZnS:Cu under easily tailored the phase transition. By precisely increasing uniaxial machine pressure (0-30 MPa), the study achieves for the first time a gradual phase transition from hexagonal wurtzite (wt-ZnS) to cubic sphalerite (sp-ZnS) at room temperature, which can be reversibly tuned through thermal annealing. High-resolution transmission electron microscopy results show that screw dislocation slip under uniaxial pressure induces sp-ZnS stacking faults within the wt-ZnS lattice, with fault density dependent on pressure and dopant concentration. Spectroscopic analyses indicate that the phase transition enhances ML emission but suppresses photoluminescence (PL) in ZnS:Mn, reflecting distinct dislocation-mediated energy transfer behaviors in ML and PL processes. This work establishes a powerful strategy for controllable phase transition engineering to tailor and enhance the ML properties, provides fundamental insights into the ML mechanisms, and offers a practical design strategy for the development of advanced luminescent materials and optoelectronic devices.