Ratiometric mechanoluminescence in single Pr³⁺ -activated LiGa₅ O₈

Mechanoluminescence (ML) materials have found potential applications in information storage, anti-counterfeiting, and stress sensing. Conventional stress sensing based on absolute ML intensity is prone to significant mistakes owing to the unpredictability of measurement surroundings. However, implementing a ratiometric ML sensing technique may considerably ameliorate this issue. In this study, a single activator-doped gallate material (LiGa₅ O₈ :Pr³⁺ ) is proposed to determine the relationship between the ML intensity and the change in local positional symmetry that occurs when the material is subjected to stress. The sensing reliability of the ML intensity ratio under different factors (Force; Content; Thickness and Materials) is systematically analyzed, where the factor that has the greatest effect on the proportional ML is the concentration, with the ML intensity asymmetry ratio decreasing from 1.868 to 1.300 varying concentration at constant stress. The colour-resolved visualization of stress sensing is further realized, which opens a new path for a ratiometric ML-based strategy to improve the reliability of stress sensing.