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

Highlights: • By co-doping Gd³⁺ ions into LiTaO₃:Pr³⁺, the phosphors had stronger ML intensity and less afterglow (AG) disturbance. • The ML intensity of the optimal sample was about 173% times compared with that in LiTaO₃:Pr³⁺. • The depth and density of LiTaO₃:0.01Pr³⁺, xGd³⁺ phosphors were investigated. • The photostimulated luminescence was also observed in Pr³⁺/Gd³⁺ co-doped LiTaO₃. • A probable mechanism was proposed to explain the multi-luminescence process in LiTaO₃:Pr³⁺,Gd³⁺. 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.