Effect of SDS on morphology tailoring of GdVO4:Eu3+ powders under hydrothermal conditions in a wide pH range

Europium doped micro-/nano-crystalline gadolinium vanadate (GdVO4:Eu3+) powders were successfully fabricated via a facile hydrothermal route. To investigate the influences of sodium dodecyl sulfonate (SDS) and pH on the morphology and luminescent properties of GdVO4:Eu3+ phosphors, different amounts of SDS were added in the hydrothermal reaction system under various pH values. The structures and morphologies of the final products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Several interesting morphologies of GdVO4:Eu3+ powders were obtained, including tetragonal, octahedron, rod-like, and dendritic. The results indicated that the pH determines the nucleation rate of GdVO4:Eu3+ crystals in the solution, and the SDS affects the crystal growth pattern by changing growth direction and forming micelles. Moreover, possible mechanisms for morphological evolution are also presented. The photoluminescent (PL) properties of the products were also characterized. All the samples exhibited the characteristic fluorescence of Eu3+ ion. In addition, the intensities of excitation and emission spectra varied with the morphological change. The product with nanocrystal morphology showed the strongest PL intensity among all the samples with different morphologies. Besides, the PL property was enhanced with good crystalline state, but weakened by serious aggregation.