Intense mechanoluminescence and photostimulated luminescence with less afterglow in Pr3+/Gd3+ co-doped LiTaO3 phosphors

LiTaO3:Pr3+,Gd3+ phosphors were obtained by traditional solid-state reaction methods. In order to study their characteristics, crystal structure, photoluminescence (PL), mechanoluminescence (ML), and thermoluminescence (TL) of materials were measured. The phosphors exhibited intense orange photoluminescence, and mechanoluminescence with two emission bands located at 511 and 618 nm, which are ascribed to 3P0 to 3H4 and 1D2 to 3H4 transitions of Pr3+, respectively. Mechanoluminescence intensity in LiTaO3:Pr3+ was greatly enhanced by co-doped Gd3+ ions. The optimal co-doped concentration of Gd3+ was 1 mol%, and the ML intensity was about 173% times higher, compared with that of LiTaO3:Pr3+. An extremely small disturbance of afterglow (AG) was noted and the trap quality was measured through TL curves. The enhanced mechanoluminescence intensity was thought to be ascribed to the regulated trap quantities and trap depths caused by co-doped Gd3+ ions. The photostimulated luminescence (PSL) was also measured, Pr3+/Gd3+ co-doped LiTaO3 turned out to have good optical storage properties. In this work, a probable mechanism was proposed to elaborate the multi-luminescence process in LiTaO3:Pr3+,Gd3+, which thus expanded the application of mechanoluminescence materials in optical information storage.