Characterization and optical properties of Dy3+ doped nanocrystalline SrAl2O4: Eu2+ phosphor

Nanocrystalline SrAl2O4: Eu2+, Dy3+ phosphors are synthesized by a reliable low temperature combustion synthesis technique (CST). Multiple techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) are used to examine the surface morphology and structural properties of SrAl2O4: Eu, Dy phosphors. The average crystal size calculated using XRD lies in nano-range. The optical properties are presented and discussed in terms of photoluminescence (PL), thermoluminescence (TL) and afterglow decay spectra. The as-obtained nanocrystalline SrAl2O4: Eu2+, Dy3+ phosphors show higher PL emission intensity (at 515 nm). After being irradiated with ultraviolet (UV) light, the phosphor samples emit green long lasting phosphorescence (LLP) with excitation and emission peaks at 324 nm and 515 nm respectively. Using TL glow curves, the trap-depth value calculated for most intense sample is found to be 0.69 eV. Furthermore, the decay curves contain a rapid and slow-decaying portion sustaining for longer time, suggesting potential applications in many fields.