Synthesis and Luminescence Properties of CaS:Eu 2+ ,Si 4+ ,Ga 3+ for a White LED

• Published in: Bulletin of the Korean Chemical Society Vol. 30; no. 2; pp. 419 - 422
• Main Authors: Oh, Sung-Il, Jeong, Yong-Kwang, Kang, Jun-Gill
• Format: Journal Article
• Language: Korean
• Published: 2009
• Subjects: Incorporation of $Si^{4+}$ and $Ga^{3+}; CaS: $Eu^{2+}$ phosphor; Luminescence; LED
• ISSN: 0253-2964; 1229-5949

The luminescence intensity of calcium sulfide codoped with $Eu^{2+},\;Si^{4+}\;and\;Ga^{3+}$ was investigated as a function of the dopant concentration. An enhancement of the red luminescence resulted from the incorporation of $Si^{4+}\;and\;Ga^{3+}\;into\;CaS:Eu^{2+}.\;The\;non-codoped\;CaS:Eu^{2+}$ converted only 3.0% of the absorbed blue light into luminescence. As the $Si^{4+}\;and\;Ga^{3+}$ were embedded into the host lattice, the luminescence intensity increased and reached a maximum of Q = 10.0% at optimized concentrations of the codopants in CaS. Optimized CaS:$Eu^{2+},Si^{4+},Ga^{3+}$ phosphors were fabricated with blue GaN LED and the chromaticity index of the phosphor-formulated GaN LED was investigated as a function of the wt% of the optimized phosphor.