Fast X-ray charged UV-visible mechanoluminescence from CaMgGeO4:Tb3+ for the realization of various colors of mechanoluminescence and long-term monitoring of sudden force

Abstract

Here, we successfully synthesized the fast-X-ray-charged UV-visible mechanoluminescence (ML) phosphor CaMgGeO₄:Tb³⁺. Fast X-ray charging (only 10 s of irradiation) can induce strong ML from CaMgGeO₄:Tb³⁺, and the ML intensity reaches saturation after only 3 min of X-ray charging. The strong ultraviolet-blue ML emission (380 and 416 nm) of CaMgGeO₄:Tb³⁺ can be used as an excitation source to effectively stimulate LED phosphors to produce ML emission of various colors. At the same time, there is a certain linear relationship between the ML intensity of the sample and the compressive load, indicating that the applied force can be accurately detected. According to the thermoluminescence results, the long-term and stable ML emission of CMG:Tb³⁺ is due to the continuous distribution of deep traps. The large number of deeply trapped electrons allows the long-term detection of stress bursts. After one-time X-ray charging for 3 min, even after a delay of 84 h, the signal-to-noise ratio can still reach 1.3 (2500 N) and 1.7 (3000 N) in multiple cycles of stress burst detection. The results have shown that CaMgGeO₄:Tb³⁺ can not only be regarded as an efficient excitation source to realize various colors of ML emission, but it can also serve as a sensor to monitor potential force bursts over extended periods, which would expand the application of ML sensors.