CTAB-assisted hydrothermal synthesis of YVO4:Eu powders in a wide pH range

Rhombus-, rod-, soya bean- and aggregated soya bean-like YVO₄:Eu³⁺ micro- and nanostructures were synthesized by a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method at 180 °C for 24 h in a wide pH range. The as-synthesized powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). The XRD results confirmed the formation of phase-pure YVO₄:Eu³⁺ powders with tetragonal structure under hydrothermal process in a wide pH range. Electron microscopic observations evidenced the morphological transformation of YVO₄:Eu³⁺ powders from rhombus-like microstructure to rod-, soya bean, and aggregated soya bean-like nanostructures with an increase in the pH of the synthesis solution. The results from the PL measurements revealed that the intensities of PL emission peaks were significantly affected by the morphologies and crystallinity of samples due to the absence of an inversion symmetry at the Eu³⁺ lattice site, and the highest luminescence intensity was observed for rod-like YVO₄:Eu³⁺ powders.