Controlling elastico-mechanoluminescence in diphase (Ba,Ca)TiO3:Pr3+ by co-doping different rare earth ions

Elastico-mechanoluminescence (EML) of diphase (Ba,Ca)TiO3:Pr3+,RE (RE includes all rare-earth-ions except Sc and Pm) is systematically investigated. The EML intensity is obviously controlled by the co-doped RE ions. Y, La, Nd, Gd, Yb, and Lu have the positive effect of improving EML, among which Gd enhances the EML intensity 61% at least. The depth and concentration of traps in (Ba,Ca)TiO3:Pr3+,RE are estimated according to the thermoluminescence curves. The consistent correlation between the dependence of EML intensity and trap concentration on the RE ions shows that the change of trap concentration induced by co-doping regulates the EML performance. Furthermore, the similar variations between the EML and afterglow (AG) intensities with the RE ions suggest the possibility that the same types of traps participate in the EML and AG processes. An EML mechanism is proposed on the basis of electrons as the main charge carriers.