Spectroscopic properties and intense red-light emission of (Ca, Eu, M)WO4 (M=Mg, Zn, Li).
The red-emitting phosphors of (Ca, Eu, M)WO4 (M=Mg, Zn, Li) were prepared through solid-state reactions, and their spectroscopic properties were studied. After the addition of a small amount of Mg2+, Zn2+ or Li+ in (Ca, Eu)WO4, the red-light emission intensity of Eu3+ increases obviously. In the luminescence spectra of the phosphors, the predominant transition emission is 5D0-->7F2 (616nm), whereas the other emissions are very weak. The excitation spectra are composed of interweaved ligand-to-metal charge-transfer bands (CTB) of W6+-O(2-) and Eu3+-O(2-), and a few 4f excitation transitions of Eu3+. Among the 4f excitation transitions of Eu3+, there are three strong excitation lines corresponding to 7F0-->5L6, 7F0-->5D2 and 7F0-->5D1 transitions, whose relative excitation intensity ratio is seriously affected when Li+ doped in the host. The new phosphors may be applied as red-emitting phosphors for white light emitting diodes.
Shi
Shikao
S
College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050016, PR China. ssk02@mails.tsinghua.edu.cn
Liu
Xingren
X
Gao
Jing
J
Zhou
Ji
J
D003116:Color; D005063:Europium / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008027:Light; D008670:Metals / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D017973:Tungsten Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction
D007477:Ions; D008670:Metals; D017973:Tungsten Compounds; D005063:Europium; D010100:Oxygen