Hydrothermal Synthesis and White Luminescence of Dy3+-Doped NaYF4 Microcrystals

2 mol% Dy3+-doped NaYF4 microcrystals with different morphologies and crystalline phases have been synthesized through a hydrothermal method without assistance of any surfactant, catalyst, or template by controlling reaction temperatures, reaction time, and molar ratios of reactants. For comparison, the samples were also synthesized by a direct coprecipitation method. The final products were characterized by X-ray diffraction, field emission scanning electron microscopy, photoluminescence excitation and emission spectra, and luminescent dynamic decay curves. Dy3+ exhibits bright white light under near ultraviolet 350 or 351 nm excitation and the white light was evaluated by chromaticity coordinates. The experimental results suggest that the obtained Dy3+-doped NaYF4 microcrystals have potential applications in white light materials.