A novel red phosphor: Ca 2GeO 4:Eu 3+

Abstract

A novel red phosphor Ca 2GeO 4:Eu 3+ was prepared by the traditional solid state reaction. X-ray powder diffraction (XRD) analysis suggested that there was no impurity phase. The study on the diffusion reflection spectra of the undoped and Eu 3+ doped Ca 2GeO 4 phosphors revealed an absorption band superposed of that of the host material and the Eu 3+ ions. And the excitation spectrum presented a dominating broad band at 250-300 nm which was attributed to both the host material absorption and the charge transfer band (CTB) of the Eu 3+ ions. The investigation on the excitation and diffusion spectra showed that there was an effective energy transfer from the host material to the Eu 3+ ions. This was favorable to the red emission of the phosphor. Photoluminescence measurements indicated that the phosphor presents bright red emission at 611 nm under UV excitation. In addition, the Al 3+ or Li + co-doping enhanced the red emission from Ca 2GeO 4:Eu 3+ by about 3 and 2 times respectively under UV excitation.