A novel red phosphor: Ca2GeO4:Eu3+

A novel red phosphor Ca2GeO4:Eu3+ 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 Eu3+ doped Ca2GeO4 phosphors revealed an absorption band superposed of that of the host material and the Eu3+ 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 Eu3+ ions. The investigation on the excitation and diffusion spectra showed that there was an effective energy transfer from the host material to the Eu3+ 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 Al3+ or Li+ co-doping enhanced the red emission from Ca2GeO4:Eu3+ by about 3 and 2 times respectively under UV excitation.