Modulating trap levels via co-doping Ca2+/Si4+in LiTaO3:Pr3+to improve both the intensity and threshold of mechanoluminescence

We report a novel mechanoluminescent phosphor Li1-xCaxSixTa1-xO3:0.01Pr3+ (x = 0-0.04). The crystal structure, photoluminescence (PL), optical diffuse reflectance spectra, afterglow (AG), fluorescence decay curves, and mechanoluminescence (ML) properties were investigated. To clarify the defect types and the mechanoluminescence mechanisms, an X-ray photoelectron spectroscopy (XPS) and thermoluminescence curve (TL) were measured. The dopants Ca2+ and Si4+ ions occupied the Li+ and Ta5+ sites, respectively. An optimal sample Li0.98Ca0.02Si0.02Ta0.98O3:Pr3+ was obtained with great enhancement in mechanoluminescence intensity, higher than that of non-doped sample LiTaO3:Pr3+ by 262%. And the compression threshold, over which the ML intensity could not maintain the linear increase, has also been greatly improved. Furthermore, the stable output of Tribo-L was achieved, which was visible to the naked eye. A probable mechanism was proposed to illustrate the mechanoluminescent process in Li1-xCaxSixTa1xO3:0.01Pr3 + (x = 0-0.04). The study indicates that adjusting trap distribution by substituting host ions may be a novel way to develop high-quality mechanoluminescence. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

A novel mechanoluminescent phosphor Li1-xCaxSixTa1-xO3:0.01Pr3+ (x = 0-0.04) was reported, and its crystal structure, photoluminescence properties, mechanoluminescence properties, and mechanisms were investigated. By optimizing the sample, significant enhancement in mechanoluminescence intensity and compression threshold was achieved, and a probable mechanism for mechanoluminescent process was proposed.