论文部分内容阅读
Tb3+ and Yb3+ codoped Lu2O3 nanophosphors were synthesized by the reverse-strike co-precipitation method.The obtained Lu2O3:Tb3+,Yb3+ nanophosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra.The XRD results showed that all the prepared nanophosphors could be readily indexed to pure cubic phase of Lu2O3 and indicated good crystallinity.The Tb3+→Yb3+ energy transfer mechanisms in the UV-blue region in Lu2O3 nanophosphors were investigated.The experimental results showed that the strong visible emission around 543 nm from Tb3+ (5D4→7F5) and near-infrared (NIR) emission around 973 nm from Yb3+ (2F5/2→2F7/2) of LuzO3:Tb3+,Yb3+ nanophosphors were observed under ultraviolet light excitation,respectively.Tb3+ could be effectively excited up to its 4f75d1 state and relaxed down to the 5D4 level,from which the energy was transferred cooperatively to two neighboring Yb3+.The Yb3+concentration dependent luminescent properties and lifetimes of both the visible and NIR emissions were also studied.The lifetime of the visible emission decreased with the increase of Yb3+ concentration,verifying the efficient energy transfer from the Tb3+to the Yb3+.Cooperative energy transfer (CET) from Tb3+ to Yb3+ was discussed as a possible mechanism for the near-infrared emission.When doped concentrations were 1 mol.％ Tb3+ and 2 mol.％ Yb3+,the intensity of NIR emission was the strongest.