Defect Localized Mechanoluminescence Model in Copper Doped Zinc Sulfide

Doped zinc sulfide microparticles exhibit the ability to mechanically tune their luminescence properties, making them promising candidates for mechanoluminescence materials that can be used in a diverse array of next-generation optoelectronics. However, their mechanism remains unclear and is often attributed to intricate analytical misinterpretations, which impede the development of a fundamental theory for improving this innovative technology. Here, we visualize the mechanoluminescence dynamics of copper-doped zinc sulfide through a hybrid technique in which structural-optical properties are correlated at an identical sample level. These results reveal that Cu defects are much more susceptible to lattice distortion when strain is applied to the global structure, which locally populates charge carriers to the electronic states responsible for mechanoluminescence. This promotes the mechanoluminescence emission from localized defect sites rather than from the global ZnS lattice. Our defect-localized mechanoluminescence model, triggered by an elastic strain, provides fundamental insights into this long-standing enigma, yielding implications for the design of high-performance materials in next-generation applications.