Luminescence properties of dysprosium doped barium alumino-silicate phosphors prepared by the solid state reaction method

A series of BaAl₂Si₂O₈:xDy³⁺ (x = 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) phosphors were prepared by the solid state reaction method. Crystal structures of the sintered phosphors were hexagonal structure with space group of P6/mmm. The chemical composition of the sintered BaAl₂Si₂O₈:Dy³⁺ (2.0 %) phosphor was confirmed by the energy dispersive X-ray spectroscopy. Thermoluminescence kinetic parameters of discussed BaAl₂Si₂O₈:xDy³⁺ phosphors were calculated by peak shape method. Under the ultraviolet excitation, emission spectra of BaAl₂Si₂O₈:xDy³⁺ phosphors were composed of broad band with the characteristic emission of Dy³⁺ ions are peaking at 478 nm (blue) and 575 nm (yellow), originating from the transitions of ⁴F_9/2 → ⁶H_j state (where j = 15/2, 13/2). Commission Internationale de L’Eclairage coordinates has been calculated for each sample and overall emission is near white light. The possible mechanisms of discussed white light emitting phosphors were also investigated. In order to investigate the suitability of the phosphors as white color light sources for industrial uses, color purity, correlated color temperature (CCT) and color rendering index (CRI) were calculated. Values of color purity, CCT, CRI were found, well within the defined acceptable range. The peak of mechanoluminescence intensity increases linearly with increasing impact velocity of the moving piston, which suggests that sintered phosphors, can be used as sensors to detect the stress of an object.