Revealing the Intrinsic Decay of Mechanoluminescence for Achieving Ultrafast-Response Stress Sensing

Converting mechanical energy into photon emission provides a promising route for intelligent sensing, self-powered lighting, and distributed energy harvesting, which is of great significance for finding a feasible solution to the current sensing technical bottleneck and energy crisis. As the basis for understanding the conversion mechanism and realizing high-frequency mechanical energy utilization, elucidating the dynamic process of intensity variation in the mechano-to-photon conversion remains a great challenge. Herein, a time-domain characterization scheme that enables to unravel the intrinsic decay of mechanoluminescence (ML) with lifetimes from milliseconds down to tens of microseconds is constructed. It is demonstrated that ML decay characterization is an important tool to reveal the dynamics of charge migration in ML materials. The ML decay in a typical self-reproducible ML material ZnS:Mn 2+ shows temperature dependence and stress fluctuation resistance, which opens up a new reliable approach for self-powered and remote temperature sensing. Finally, benefiting from the shortest ML lifetime recorded to date, an ultrafast-response stress sensor that enables to detect individual pulses of ultrasonic waves with ML sensing technology is developed.