Daylight-activated recoverable mechano-luminescence material SrGa12O19: Tb3+ for enhanced speed detection applications

Mechano-luminescence (ML) materials exhibit significant potential in anti-counterfeit coding, structural detection, and mechanical sensing due to their unique force-light conversion properties. However, current research predominantly focuses on recoverable ultraviolet irradiation and triboelectric effects within non-centrosymmetric crystal structures. In this study, we have successfully synthesized a doped centrosymmetric crystal structure, SrGa₁₂O₁₉ (SGO): Tb³⁺, which displays green ML property and is capable of recovery under daylight irradiation. Furthermore, co-doping with Sb³⁺ ions allowed a 13-fold increase in the trap concentration that significantly enhanced its long persistent luminescence (LPL) performance. Temperature-dependent ML properties, along with density functional theory calculations, provide additional confirmation of the crucial role played by trap structure in the conversion process of force into light. Additionally, a dual-function film with ML and LPL effects has been developed through coupling the polydimethylsiloxane and SGO: Tb³⁺, Sb³⁺ phosphors, which has been effectively applied to warning speed measurement on hazardous roads at night. This work thus extended the design strategies and innovative applications of emergent ML materials.