Ratiometric mechanoluminescence in LiSrPO4:Eu2+/Eu3+ for stress sensing: Dopant concentration dependent sensitivity

Ratiometric mechanoluminescence (ML) has been recently proposed for stress-sensing, which is regarded to be superior to the traditional ML-intensity based sensing route in terms of accuracy and cycle stability. The dual-activator strategy to realize the ratiometric ML takes advantage of instantaneous change of local crystal field environment induced by stress, where the structural characteristics of host are supposed to play major role. Herein, LiSrPO4:Eu2+/Eu3+ phosphors have been explored to realize the ratiometric ML, with the focus on the influence of Eu dopant concentration on the sensitivity of the stress-dependent ratiometric ML. The dependence between the dopant concentration and sensitivity can be interpreted in terms of host phase structure evolution with dopant concentration.