Blue emitting phosphor Sr0.8Ca0.2Al2+ySi2-yO8:Ce3+: Substitution of Al-Si, structural modification, luminescence property and application

Abstract

A blue emitting phosphor Sr0.8Ca0.2-xAl2+ySi2-yO8:xCe3+ was synthesized by a high temperature solid state method, and its structure and the luminescence properties were studied in detail by the XRD, decay curves, emission, excitation and temperature spectra. We change the half-width of the emission spectrum to improve the color rendering of the device through matrix control. As a result, for Sr0.8Ca0.2Al2Si2O8:xCe3+, with the increase of Ce3+, there is a red-shift of 25 nm under the 330 nm excitation. With the addition of Al3+, the (Ca1/Sr1)O6 and (Ca2/Sr2)O7 polyhedron shrinks because the change of the adjacent (Al/Si)O4 polyhedron and the symmetry increases, which leads to the weakening of the crystal field splitting. The emission peak of Sr0.8Ca0.2-xAl2+ySi2-yO8:xCe3+ shows a blue-shift of 20 nm, the full widths at half maximum gets narrowed (FWHM = 54.3 nm) and color purity has increased, which is the result of comprehensive action of crystal field splitting and unit cell volume. Ce3+ in the material has a short lifetime (<6 ns), which is beneficial for white LEDs. Al3+ substituting for Si4+ enhances the luminescence intensity and improves color purity of the phosphor. Warm white light was obtained by mixing this phosphor with commercial phosphors, and its color rendering index Ra was 94.7, the correlated color temperature was 4053 K, and the CIE was (0.3810, 0.3864). These results indicate that Sr0.8Ca0.2Al2+ySi2-yO8:Ce3+ may be used as a near ultraviolet excited narrow-band blue phosphor in the field of white light emitting diodes.