Luminescence studies of dysprosium doped strontium aluminate white light emitting phosphor by combustion route

In the present investigation dysprosium doped strontium aluminate phosphor was prepared by combustion synthesis method. The crystal structure of the prepared phosphor was consistent with standard monoclinic phase with a space group P2(1). According to the TEM analysis, the particle size was found to be in the nanometer range. The trap parameters which are mainly activation energy (E), frequency factor (s) and order of the kinetics (b) were evaluated by using the peak shape method. Under the ultraviolet (365 nm) excitation, photoluminescence (PL) spectra showed characteristic emission bands at 480 (blue), 573 (yellow) and 670 nm (red) due to F-4(9/2) -> H-6(15/2), F-4(9/2) -> H-6(13/2) and F-4(9/2) -> H-6(11/2) transitions of Dy3+ ions. Combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram and possible mechanism of white light emitting SrAl2O4:Dy3+ phosphor was also investigated. The value of correlated color temperature (CCT) was found, well within the defined acceptable range (5965 K). The mechanoluminescence (ML) intensity of SrAl2O4:Dy3+ phosphor increases linearly with increasing impact velocity of the moving piston. Thus, the present investigation indicates the piezo-electricity was responsible to produce ML in prepared phosphor.