Synthesis and photoluminescence of Eu2+ doped Ca-α-SiAlON phosphor

Luminescence conversion materials with the formula CaxEuySi12-(3x+4.5y) Al3x+4.5yOx+1.5yN16-(x+1.5y) (x=0.220-1.525, y=0.02-0.15) have been synthesized from α-Si3N4, AlN, Eu2O3 and CaCO3 powders. Using X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), UV-Vis spectrophotometer and fluorescent spectrophotometer, the influences of different compositions and sintering process on Eu2+ distribution and optical properties of Ca-α-SiAlON:Eu2+ were studied. The powders with single Ca-α-SiAlON phase doped Eu2+ have been obtained within the range of composition we studied. Rising sintering temperature can improve the uniformity of Eu2+ dispersion in α-SiAlON lattice. Ca-α-SiAlON:Eu2+ had high adsorption in the UV-visible spectral region. Two broad bands were observed in the excitation spectrum centered at 270 and 400 nm, and a single broad emission band centered at 570 nm was observed in the emission spectrum. Ca-α-SiAlON:Eu2+ phosphors synthesized in the mixture of hydrogen and nitrogen atmosphere had stronger emission intensity than that synthesized in nitrogen atmosphere.