Processing effect on the luminescence and raman spectra of Gd_1−xVO₄:Eu_x³⁺ phosphors

Nano-sized Eu³⁺-activated Gd_1−xVO₄ phosphors were prepared via hydrothermal reaction coupled with the coprecipitation method at a low temperature (230 °C). The coprecipitation provided chemical homogeneity. However, it resulted in a low crystallinity and reduced emission and excitation characteristics. Raman study showed that Gd–O bond lengths changed in powders, depending on the level of crystallinity. The particle morphology was controlled using ethylenediaminetetra-acetic acid during the hydrothermal reaction. Particle shapes in the nano-size range affected the vibration of atoms in the lattice, changing photoluminescence properties.