Lanthanide doped Y_6O_5F_8/YF_3 microcrystals: Phase-tunable synthesis and bright white upconversion photoluminescence properties

摘要

High-quality Y_6O_5F_8/YF_3 microcrystals have been synthesised by using a hydrothermal and subsequent calcination route. Upon changing the initial solution pH value, the as-prepared microcrystal can be well tuned from YF_3 octahedron microcrystals to YF_3 hollow spheres and finally to Y_6O_5F _8 microtubes. The as-obtained microcrystals have been characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectra. When the Y_6O _5F_8:Ln~(3+) microtubes are excited by a 980 nm continual wave laser diode, bright red, green, and blue room temperature upconversion PL emissions have been observed. A series of white light emissions have been obtained by precisely adjusting dopants concentration in Y _6O_5F_8 microtubes.