Sound, Force and Light Induced Emissions from Er³⁺‐Mn²⁺ Doped ZnS/CaZnOS Heterostructure for Remote Temperature Monitoring via Photo‐ and Mechanoluminescence

Abstract Mechanoluminescence (ML) is a powerful phenomenon that enables light generation induced with mechanical or acoustic waves, and remote temperature sensing via luminescence thermometry techniques. In this work, the multi‐functional, ML‐active materials based on Er³⁺ and Mn²⁺ co‐doped ZnS/CaZnOS heterostructure are developed for remote temperature monitoring and visual sensing of force and sound. The material exhibits characteristic photoluminescence (PL) under UV and NIR (up‐conversion) excitation, with energy transfer from Er³⁺ to Mn²⁺ influencing the emission color. The effects of force‐to‐light conversion are studied in detail by measuring the ML intensity versus the applied power for Er³⁺ and Mn²⁺ emission in the single‐doped and co‐doped materials. Temperature‐dependent PL is utilized to calibrate luminescence thermometry response, with Er³⁺ thermally‐coupled levels and non‐thermally‐coupled levels of Er³⁺/Mn²⁺, providing temperature sensing capabilities. The unique combination of sound‐induced ML with luminescence thermometry allowed optical temperature detection, alike during the drilling process, and in the externally heated system, using pulsed sonications. Whereas, applying continuous excitation, the sound‐to‐heat conversion is studied and visualized using the developed ML‐based optical thermometers. This approach demonstrates the excellent application potential of sound‐to‐light conversion for remote monitoring and, more importantly, for excitation‐light‐free temperature probing of different systems and working devices.