Enhancing Mn-Activated Mechanoluminescence via Pressure-Regulated Local Structure in Centrosymmetric BaZnOS for Dynamic Response Applications.

Self-recoverable mechanoluminescence (ML), typically observed in non-centrosymmetric luminescent materials, has recently been reported in centrosymmetric systems such as Mn-activated BaZnOS. However, the underlying mechanism and structure-luminescence relationship remain unclear, hindering the development of high-performance optoelectronics. Here, it is demonstrated that Mn2+-activated BaZnOS exhibits strong, reproducible, and self-recoverable piezoelectrically activated ML emission at the GPa level. Under compression at 0.6 GPa s-1, the ML intensity exhibits 10-fold enhancement from ambient pressure to 1.5 GPa, but weakens above 1.5 GPa. Interestingly, it shows an oscillatory ML emission with time scale of 110 ms at rates of 2.3-2.7 GPa s-1. The ML behavior is distinct from photoluminescence (PL) with time scale of 0.3-1.5 ms, which shows slight attenuation at 0-4 GPa, exhibits threefold boost at 4-12 GPa, and then weakens above 12 GPa. The analyzed results show that the distinctive ML and PL behaviors stem from pressure-regulated local structure, significantly affecting the local piezoelectricity and defect traps. Additionally, Mn2+-activated BaZnOS exhibits diverse dynamic responses in both temporal and spatial dimensions for potential optoelectronic applications.