Abstract
In this study, calcium strontium aluminate phosphors Ca x Sr 1− x Al 2O 4 doped 1 mol% Eu 2+ was prepared as the fluorescent material for UV–LED performed as a light source. The crystal structure, peak wavelength ( λ p), and chromaticity were investigated by XRD patterns and photoluminescence (PL), respectively. The inhomogeneous broadening effects of emission spectra were also discussed by electron paramagnetic resonance (EPR). In the Ca x Sr 1− x Al 2O 4:Eu 2+ system, the dominant structure transforms from monoclinic to hexagonal at 0.2 ≤ x ≤ 0.5, and λ p ranges from 440 to 529 nm. The shift in λ p could be explained by the crystal field effect, which is affected by different coulomb attracting forces due to the various fractions of Ca 2+/Sr 2+ in the host lattice. The near-white chromaticity of Ca 0.5Sr 0.5Al 2O 4:Eu 2+ (1 mol%) phosphor was explained by the reasons of inhomogeneous broadening and re-absorption effects. The EPR spectra indicated that the inhomogeneous broadening effect could be attributed to the substitutional disorder (compositional disordering) of Ca 2+and Sr 2+ in the host lattice.
Published Version
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