Facile synthesis and enhancement upconversion luminescence of ErF3 nano/microstructures via Li~+ doping

摘要

A series of ErF3 samples with different morphologies (flake, truncated octahedral, flower-like and rice-like microcrystals) and sizes (20 nm-2 urn) were prepared by an aqueous-based hydrothermal and coprecipitation route, respectively. The crystal structure of ErF3 is firstly established via the Rietveld refinement result of the powder XRD data. In addition, the ErF3 matrix without doping sensitizer or activator shows bright red upconversion emission under excitation at 980 nm. It is worthwhile pointing out that ErF3 with an octahedral morphology demonstrates the highest relative intensity, with that of flower-like microcrystals following, but the nanoflakes show the lowest intensity, and the relative intensity is almost 8 times as low as that of the microcrystals. Further doping with Li~+ would enhance the upconversion luminescence intensity, and the upconversion emission intensity of the optimal sample with doping 6 mol% Li~+ is four times stronger than that of a Li~+ free sample. Furthermore, upon electron beam excitation, the cathodoluminescence properties of a ErF3 matrix as a new upconversion host are also studied, which is an interesting phenomenon.