Luminescence of SiO 2 -BaF 2 :Tb 3+ , Eu 3+ Nano-Glass-Ceramics Made from Sol-Gel Method at Low Temperature.

The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE 3+ ) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF 2 nanocrystals co-doped with Tb 3+ , Eu 3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF 2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol-gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol-gel materials was carried out by excitation and emission spectra along with decay analysis from the 5 D 4 level of Tb 3+ . As a result, the visible light according to the electronic transitions of Tb 3+ ( 5 D 4 → 7 F J (J = 6-3)) and Eu 3+ ( 5 D 0 → 7 F J (J = 0-4)) was recorded. It was also observed that co-doping with Eu 3+ caused the shortening in decay times of the 5 D 4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb 3+ /Eu 3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.