Abstract
We report a novel mechanoluminescent phosphor Li_(1-x)Ca_xSi_xTa_(1-x)O_3:0.01Pr~(3+) (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 Ca~(2+) and Si~(4+) ions occupied the Li+ and Ta~(5+) sites, respectively. An optimal sample Li_(0.98)Ca_(0.02)Si_(0.02)Ta_(0.98)O_3:Pr~(3+) was obtained with great enhancement in mechanoluminescence intensity, higher than that of non-doped sample LiTaO_3:Pr~(3+) 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 Lil-xCaxSixTal-xO3:0.01Pr3 + (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.
NSTL
Elsevier