Hydrothermal Synthesis, Characterization and Luminescence Properties of YbVO_4:Ln~(3+) (Ln~(3+) = Er~(3+), Tm~(3+), Ho~(3+)) Nanocrystals

摘要

Ytterbium orthovanadate YbVO_4 nanocrystals with uniform size and shape were successfully synthesized through a facile hydrothermal approach using sodium tartrate (Na_2tar) as the chelating ligand. X-ray diffraction (XRD), energy-dispersive X-ray spectrum (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and photoluminescence (PL) spectra were taken to characterize the phases, morphologies, sizes, and luminescence properties of the samples. The results indicate that the YbVO_4 samples can be rationally modified in size and morphology by altering the Na_2tar content, pH value and reaction time. The possible formation mechanism of the YbVO_4 samples is proposed on the basis of time-dependent experiments. Additionally, the UC luminescence properties and the emission mechanisms of YbVO_4:Ln~(3+) (Ln~(3+) = Er~(3+), Tm~(3+), Ho~(3+)) samples were systematically investigated, which show green (Er~(3+), ~4S_(3/2), ~2H_(11/2) → ~4I_(15/2)), blue (Tm~(3+), ~1G_4 → ~3H_6) and green (Ho~(3+), ~5S_2 → ~5I_8) luminescence under 980 nm NIR excitation, respectively. These merits of multicolor emissions in the visible region endow this kind of material with potential applications in the field of light display systems, lasers, and optoelectronic devices.