Oxonitridosilicate phosphors with compositions of (Y1−xCex)2Si3O3N4 (x=0−0.2) have been synthesized by solid state reaction method. The structures and photoluminescence properties have been investigated. Ce3+ ions have substituted for Y3+ ions in the lattice. The emission and excitation spectra of these phosphors show the characteristic photoluminescence spectra of Ce3+ ions. Based on the analyses of the diffuse reflection spectra and the PL spectra, a systematic energy diagram of Ce3+ ion in the forbidden band of sample with x=0.02 is given. The best doping Ce content in these phosphors is ∼2 mol%. The quenching temperature is ∼405 K for the 2 mol% Ce content sample. The luminescence decay properties were investigated. The primary studies indicate that these phosphors are potential candidates for application in three-phosphor-converted white LEDs.
Oxonitridosilicate phosphors with compositions of (La1−xCex)5Si3O12N (x = 0–0.1) have been synthesized. The XRD analyses show that all the compounds are single polycrystalline La5Si3O12N phase. La atoms occupy two crystallographic sites in the structure. Two groups of photoluminescence spectra have been observed and can be ascribed to the excitation and emission of the two types of Ce3+ photoluminescence centers (Ce(1)3+ and Ce(2)3+) in the crystallographic sites of La(1) and La(2). The energy transfer between the two types of photoluminescence centers has been discussed. Schematic energy levels of Ce3+ ions at the two crystallographic sites are given. Luminescence concentration quenching occurs when Ce content is more than 3 mol%. The quenching temperature is evaluated to be about 406 K for the 3 mol% Ce content sample. This study shows these phosphors potential candidates for application in three-phosphor-converted white LEDs.
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