Mechanics-induced triple-mode anticounterfeiting and moving tactile sensing by simultaneously utilizing instantaneous and persistent mechanoluminescence

In this work, ultra-strong yellow and green mechanoluminescence was presented for Y₃Al₅O₁₂:Ce³⁺ and Ba_0.5Sr_0.5Si₂O₂N₂:Eu²⁺, respectively. In addition to the emitting color, the above materials showed distinct trap dependence/independence and spontaneous radiation behaviors, leading to instantaneous mechanoluminescence without any afterglow for Y₃Al₅O₁₂:Ce³⁺ and persistent mechanoluminescence for Ba_0.5Sr_0.5Si₂O₂N₂:Eu²⁺. By ingeniously combining the above unique mechanoluminescence behaviors, two types of intriguing and unprecedented devices were achieved. The devices are a mechanics-induced triple-mode anticounterfeiting device capable of displaying embedded information in varied emitting colors and dynamic patterns and a comprehensive tactile sensor that can simultaneously sense/record the contact load, motion trail, and contact position for objects moving on the surface. This work is the first to present application designs by simultaneously utilizing transient and persistent mechanoluminescence. The as-fabricated devices showed unique superiority and advancement in their own fields. Particularly, the mechanoluminescence-based tactile sensor realized comprehensive sensing functionalities within a single unit and required no extra circuit designs.