Rare earth doped LiYbF ₄ phosphors with controlled morphologies: Hydrothermal synthesis and luminescent properties

High quality monodisperse LiYbF ₄ microparticles with shape of octahedron had been prepared via a facile hydrothermal route. The crystalline phase, size, morphology and luminescence properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra and Commission Internationale de L'Eclairage (CIE 1931) chromaticity coordinates, respectively. The influences of reaction temperature, reaction time and the molar ratio of EDTA to Yb ³⁺ on the crystal phases and shapes of as-prepared products had been investigated in detail. The upconversion (UC) luminescence properties of LiYb _1-xF ₄:xEr ³⁺ (x =0.1, 0.2, 0.5, 1, 2, 5 and 10 mol%) particles with octahedral microstructures were studied under 976 nm excitation. The results showed that the luminescence colors of the corresponding products could be tuned to bright green by changing the doping concentration of Er ³⁺ ion. The luminescence mechanisms for the doped Er ³⁺ ion were thoroughly analyzed, showing great potential in applications such as biolabels, displays and other optical technologies.