Self-Purification-Dependent Unique Photoluminescence Properties of YBO3:Eu3+ Nanophosphors under VUV Excitation

A series of different concentrations of Eu 3+ doping in YBO 3 nanophosphors were successfully prepared by a surfactant-assisted solvothermal and heat-treatment process. Their photoluminescence (PL) properties were investigated under vacuum ultraviolet (VUV) and ultraviolet (UV) excitation. In comparison with the change trend of emission intensities in UV spectra, we found a unique phenomenon in the VUV spectra of YBO 3:Eu 3+ nanophosphors: the PL intensities are not sensitive to the activator doping concentrations. Although the doping concentrations were changed in a large range (2.5−25%), the PL intensities were maintained in a certain value. This phenomenon was also not observed in the bulk YBO 3 phosphor. We gave a detailed explanation to this phenomenon by using the “self-purification” effect in nanosystems. It indicated that the activator in the nanophosphor is not a homogeneous distribution but tends to gather on the surface, which will also cause effective activator amounts for VUV luminescence to be very low.