Largely enhanced mechanoluminescence properties in Pr3+/Gd3+ co-doped LiNbO3 phosphors

Pr3+/Gd3+ co-doped LiNbO3 phosphors were prepared by a traditional solid-state reaction method and their structure, photoluminescence, mechanoluminescence and thermoluminescence were investigated. The results showed that the LiNbO3 phase with a rhombohedral structure and an R3c space group was successfully prepared. Mechanoluminescence intensity in nonstoichiometric LiNbO3:Pr3+ was largely increased by introducing Gd3+ ions. The optimal co-doped concentration of Gd3+ was 1 mol% and the enhanced ML intensity of LiNbO3:0.01Pr3+, 0.01Gd3+ was about 177% times compared with that of LiNbO3:0.01Pr3+. The effect of Gd3+ co-dopants on trap levels were explored through thermoluminescence curves. The enhancement of mechanoluminescence intensity was suggested to be ascribed to the regulated trap quantities caused by co-doped Gd3+ ions. Appropriate co-dopants are proved to be effective sensitizers for mechanoluminescence materials.