Oxygen-assisted preparation of mechanoluminescent ZnS: Mn for dynamic pressure mapping

Mechanoluminescent materials that convert mechanical stimuli to light emission have attracted extensive attention for potential applications in human-machine interactions. Here, we report a simple and available novel approach for the oxygen-assisted preparation of ZnS: Mn particles by solid-state reaction at atmospheric pressure without the formation of the corresponding oxides. The existence of O₂ has a positive impact on the formation of S vacancies in wurtzite-phase ZnS, leading to the introduction of Mn²⁺ ion luminescent centers and shallow donor levels, which can improve the electron-hole recombination rate. The O₂ ratio and Mn²⁺ ion doping concentration have significant effects on the luminous efficiency, which is optimal at 1%–20% and 1 at.%–2 at.% respectively. In addition, a device based on the piezo-photonic effect with excellent pressure sensitivity of 0.032 MPa^-1 was fabricated, which can map the two-dimensional pressure distribution ranging from 2.2 to 40.6 MPa in situ. This device can be applied to real-time pressure mapping, smart sensor networks, high-level security systems, human-machine interfaces, and artificial skins.