ABSTRACT
LaBO3:xDy3+ (x = 0.05 mol%, 0.1 mol%, 0.2 mol%, 0.5 mol%, 1 mol% and 2 mol%) phosphors were synthesized by solid-state reaction method. X-ray diffraction technique was used to confirm the formation of compound. Photoluminescence emission spectra shows two emission peaks at 470 nm and 575 nm when excitation wavelength is set at 352 nm. Photoluminescence intensity increases upto 1 mol % of Dy3+ and then starts decreasing. Dipole-dipole interaction is found to be responsible for concentration quenching of photoluminescence intensity. Commission Internationale de I'Eclairage (CIE) chromaticity diagram demonstrates that the phosphor emits in bluish white region of the visible spectrum. Critical energy transfer distance between dopant ions was determined. The mechanoluminescence characteristics were studied by the impact method. The peaks of both the mechanoluminescence (ML) intensity and the total ML intensity of the UV exposed phosphors increases with increasing impact velocity for 1 mol % concentration of Dy3+. The ML sensitivity of the LaBO3:Dy3+ (Dy3+ = 1 mol %) phosphor is comparable with the reported ML of various inorganic phosphors. The thermoluminescence characteristics of the samples were also investigated. Thermoluminescence glow peaks were recorded with 480 Gy, 80 Gy and 20 Gy dose of γ-irradiation from Co60 Source. TL trapping parameters were determined by Chen's peak shape method and glow curve deconvolution method. LaBO3:Dy3+ phosphors were found to be good mechanoluminescent materials and can be used in stress sensing application.
