KLaF4:Nd3+doped transparent glass-ceramics processed by spark plasma sintering

Transparent oxyfluoride glass-ceramics (GCs) containing KLaF4 nanocrystals (NCs) doped with Nd3+were prepared by Spark Plasma Sintering (SPS). Glass powder pellets were sintered under a vacuum atmosphere, optimizing the processing parameters such as particle size, pressure, temperature, and holding time to obtain full densification. Transparency decreased when decreasing the particle size due to higher carbon contamination from the die. The α-KLaF4 crystalline phase was identified by X-ray diffraction (XRD) and its average crystal size was 10–20 nm. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of KLaF4 nanocrystals with incorporated Nd3+ions. Low-temperature site-selective emission and excitation spectra of Nd3+ions confirmed that α- KLaF4 was the predominant polymorph, although a minor presence of β- KLaF4 was also demonstrated. [Display omitted]