| Summary: | In this study, transparent oxyfluoride glass-ceramics (GCs) with NaLaF<sub>4</sub> nanocrystals (NCs) were prepared by the sol–gel method for the first time. Three different molar ratios of La(CH<sub>3</sub>COO)<sub>3</sub>/Na(CH<sub>3</sub>COO) were used to obtain the GCs, which were sintered at 450, 550 and 650 °C for 1 min. X-ray diffraction (XRD) was employed to follow the evolution of the xerogel during the heat treatments and to study crystal growth for the three temperatures. In all cases, the LaF<sub>3</sub> crystalline phase was present, but crystallization of NaLaF<sub>4</sub> was only promoted at 650 °C. Thermogravimetric and thermodifferential analysis (TGA-DTA) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the crystallization process. High-resolution transmission electron microscopy (HRTEM) was employed to confirm NaLaF<sub>4</sub> crystallization and determine the size distribution. The incorporation of Nd<sup>3+</sup> ion into NaLaF<sub>4</sub> and LaF<sub>3</sub> nanocrystals was confirmed by site-selective emission and excitation spectra. The Nd<sup>3+</sup> emission intensities in both phases depend not only on the NaLaF<sub>4</sub>/LaF<sub>3</sub> ratio but also on their emission efficiencies.
|
|---|
