Synthesis and Characterization of CaF2 Nanoparticles with Different Doping Concentrations of Er3+

Calcium fluoride nanoparticles with various amounts of erbium ion dopants were prepared by CTAB/C4H9OH/C7H16/H2O reverse micro-emulsion method. The nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), absorption and fluorescence spectra. The XRD patterns indicate a typical cubic fluorite structure and no other impurities. TEM results show the synthesized particles having uniform grain size and without agglomeration. FTIR spectra reveal that there are some amounts of -OH, NO3- and other organic functional groups on the particle surfaces before the annealing process. Many absorption peaks and bands are present in the absorption spectra, corresponding to the rich energy levels of erbium ion. The Red-Shift of absorption bands and Blue-Shift of fluorescence peaks can be attributed to the weakened energy level split as a result of the decrease in crystal field strength.