Sensitive mechanoluminescence from Eu2+, Tm3+ co-doped Sr3Al2O5Cl2 phosphors

In this paper, sensitive mechanoluminescence (ML) phosphors Sr3Al2O5Cl2:Eu2+, Tm3+ have been developed. The effect of co-doped Tm3+ ions on the ML properties of the samples were investigated. The results showed that the ML emission, afterglow emission and photoluminescence were similar all consisted of a broad band peated at 610 nm, which can be ascribed to the 4f65 d1→4f7 transition of Eu2+. This result indicated that the ML also originated from the Eu2+ emitting center not the Tm3+ ions. The thermoluminescence and ML results have confirmed that the shallow traps (0.656 eV) created by the Tm3+ ions answered for the origin of sensitive ML. Furthermore, following the increase of co-doped Tm3+ ions, the density of shallow trap increased greatly, which brought out strong sensitive ML intensity accordingly. When the content of Tm3+ reached 0.05, sensitive ML intensity of the sample arrived at the strongest under the compressive load of 10–50 N. In addition, the obtained results also showed that the deep traps can provide the possibility to produce long time stable ML emission under strong compressive load of 10–800 N. Even after 120 min, stable obvious ML signals can be observed. All these results suggested that Sr3Al2O5Cl2:Eu2+, Tm3+ phosphors possessed great potential in precious detection of weak stress and long time stable ML detection.