Highly efficient mechanoluminescence of SrAl2–xYxO4:Eu2+,Dy3+ via trap regulation for dynamic signature anticounterfeiting

Abstract

Mechanoluminescence (ML) materials have shown tremendous application potential due to their luminescent properties stimulated by mechanical energy. Owing to the narrow awareness of alterations in the crystal field environment of materials, the ML performance optimization is severely restricted. Here, a novel strategy of doping Y3+ into SrAl2O4:Eu2+,Dy3+ phosphors was employed by solid-phase reaction, significantly improving the ML performance. Based on analysis of structure and luminescent properties, it is proved that Y3+ occupies Al3+ sites, causing lattice expansion and crystal field distortion, altering trap engineering, strengthening carrier de-trapping ability, and improving ML performance. Through thermoluminescence (TL) analysis, the brighter ML behavior can be attributed to the carriers re-combination generated by high-density deep traps of 0.836 eV and above. Materials were also investigated in relation to pressure, stability and repeatability and conducive to achieving dynamic anticounterfeiting of personal signature. This study also provides more evidence that doping ions is an efficient tactic for greatly enhancing ML performance.