Preparation of Sm3+–Eu3+ coactivating red-emitting phosphors and improvement of their luminescent properties by charge compensation

• DOI: 10.1007/s00340-009-3749-8
• Publication Date: 2009-10-09T22:11:49Z
• Authors: F.-b. Cao; Y.-j. Chen; Y.-w. Tian; L.-j. Xiao; L.-k. Li
• Keywords: Optical materials

By charge compensating, a series of red-emitting phosphors Ca0.54Sr0.16Ca0.54Sr0.31Eu0.08Sm0.02(MoO4)0.6(WO4)0.4 were synthesized. Two approaches to charge compensation were used: (a) 2Ca2+/Sr2+→Eu3+/Sm3++M+, where M+ is a monovalent cation like Li+, Na+ or K+; (b) Ca2+/Sr2+→Eu3+/Sm3++N−, where N+ is a monovalent anion like F−, Cl−, Br−, or I−. One red LED was made by combining the phosphor and 390–405 nm emitting LED chip under 20 mA forward-bias current, the color purity, chromaticity coordinates and the luminous intensity of which were 99.5%, x=0.66, y=0.33, 5600 mcd, respectively.