Effect of Eu Content on Microstructure and Luminescence Properties of WO3 Nanoparticles

Tungsten trioxide (WO 3 ) nanoparticles were prepared by the citric acid method, using ammonium paratungstate as the tungsten source, and doped with rare earth europium (Eu) under various pH values and Eu content. The microstructure, morphology, and luminescence properties of the prepared samples were characterized by XRD, SEM, and a fluorescence spectrometer. The results show that Eu 3+ doped WO 3 nanoparticles were successfully obtained by the citric acid method, the prepared nanoparticles were spherical and rhomboidal, and the average particle size of the prepared samples reached 56 nm. The excitation spectrum consisted of a series of linear excitation peaks in the range of 250–550 nm. The strongest excitation peak was located at 543 nm, which belongs to the 7 F 0  →  5 D 1 transition of Eu 3+ .