Influence of Concentration Effect and Au Coating on Photoluminescence Properties of YVO4:Eu3+Nanoparticle Colloids

The YVO 4:Eu 3+ and YVO 4:Eu 3+ @Au nanoparticle (NPs) colloids were prepared by a wet chemistry method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV−vis absorption spectra. The influence of particle concentration and Au coating on the photoluminescence properties of the colloids was studied in emphasis. It was interesting to observe that in the colloid phase the location of excitation bands induced by the energy transfer (ET) from the VO 4 3− groups to Eu 3+ gradually shifted to red with the concentration increase of YVO 4:Eu 3+ NPs, while the intensity of the bands demonstrated an optimum value and the luminescence decay dynamics gradually deviated from exponential functions owing to the strong interactions among YVO 4:Eu 3+ NPs. After coating with Au shells, the luminescence intensity for the ET excitation at 269 nm increased nearly two times, which was mainly attributed to the isolation effect among YVO 4:Eu 3+ NPs. This work is very helpful of understanding the photoluminescence properties of rare earth (RE) doped NPs in the colloids.