EDTA-assisted hydrothermal synthesis, characterization, and luminescent properties of YPO4·nH2O:Eu3+ (n = 0, 0.8) microflakes and microbundles

In this paper, the YPO4:Eu3+ (5%) microflakes and YPO4·0.8H2O:Eu3+ (5%) microbundles have been synthesized by a simple EDTA-assisted hydrothermal method. The X-ray powder diffraction (XRD), thermogravimetric and differential thermal analysis (TG/DTA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and photoluminescence (PL) were employed to characterize the as-obtained products. It was found that the composition of the product could be changed from YPO4:Eu3+ (5%) to YPO4·0.8H2O:Eu3+ (5%) with a further increase in the amount of EDTA 0.5–1.0 g. The YPO4:Eu3+ (5%) presented the pure tetragonal phase and flake-like microstructure, while the YPO4·0.8H2O:Eu3+ (5%) exhibited the hexagonal phase and bundle-like morphology. The possible formation mechanisms of the two architectures were put forward on the basis of different EDTA amount-morphology experiments. A detailed investigation on the photoluminescence of YPO4·nH2O:Eu3+ (5%) different samples indicated that the luminescent properties of products were strongly dependent on the compositions, morphologies, coordination environment and crystal field symmetry.