A series of Eu3+-Bi3+ co-doped CaMoO4 red phosphors were synthesized via the solid-sate reaction method. The crystal structures of the obtained samples were identified by X-ray powder diffraction (XRD). The photoluminescence property was investigated, and the results showed that the intensity of excitation spectra and emission spectra could be changed with different doping ratios of Bi3+/Eu3+. The proposed explanation of these changes was from the energy transfer between Bi3+ and Eu3+ and the unbalanced charge from the substitution of Eu3+ and Bi3+ for Ca2+ in CaMoO4. The obtained samples are a promising red light emitting phosphor for the needs of different excitation sources with near-UV and blue GaN-based chips.
Eu3+ and Ho3+ doped Sr2TiO4 were synthesized by using solid-state reactions. Samples sintered at 1300 oC for 6 h could be indexed to Sr2TiO4 with a single phase. Eu3+ in Sr2TiO4 emitted orange light under the excitation at 365 nm in a broad band which was coupled well with the strongest emission of high pressure mercury vapor lamps. Ho3+ in Sr2TiO4 emitted yellow light under blue excitation from 450 to 460 nm which agreed well with the emission of blue InGaN-based light-emitting diodes. The present results indicated that Sr2TiO4 was a promising host for high pressure mercury vapor lamps or white light-emitting diodes.
The luminescent properties of Sr2.97MgSi2O8:Eu2+0.01 phosphors were investigated with different Ln3+0.02(Ln3+:Dy3+,Er3+,Ho3+) co-dopants. The co-dopants had no influence on both the structure of the lattice and the position of the emission peak. However, the afterglow properties of samples were enhanced with different co-dopants. The afterglow duration of the Dy3+ co-doped sample was longer than that of the others. Furthermore, the co-doping samples had stronger thermoluminescence (TL) intensity and therefore longer afterglow duration. At last, the self-reduction of Eu3+→Eu2+ was observed in an silicate compound of Sr3-xMgSi2O8:xEu phosphor in air condition. This is the first time to show a blue long afterglow phosphor synthesized avoiding reducing atmosphere.
