Inorganic Composites Luminophors in Lithium-Borate Glasses with Rare-Earth Elements for White-Emitting Diodes

The paper describes the synthesis of novel luminescent composite system, based on lithium-borate glass matrix with addition of rare-earth elements and yttrium-aluminum garnet finely divided powder. The new chemical composition of glass has been selected, composite’s fabrication technology was developed, the temperature conditions of glass and luminophore sintering as well. The spectral characteristics of the obtained luminescent composites are measured, and chromaticity diagrams are considered. The radiation spectra showed a maximum of about 560 nm, the maximum spectral intensity of the radiation is about 90 μw/cm2/nm. Powerful energy saving source of white light was produced.

Optical Properties of Lithium Borate Glass Containing Barite

Through this research we have prepared samples of glass, which includes 60 mol%B2O3 – x mol %barite – (40-x) mol %Li2O, where x= 5, 7.5, 10, and 15 mol%. The samples fabricated by the melt quenching technique. The samples are melted in alumina crucible at 1473 K for 1.5 h in an electric muffle furnace (LENTON). The glasses were casted into stainless molds, and then immediately transferred to an annealing furnance at about 400°C. The aim of this work is to determine the extent of the effect of raw barite on the physical and optical properties of this glass. The optical transmittance and reflectance spectrum of the glasses in this work were determined in the wavelength range 300–2500 nm at room temperature. The physical and optical properties of the following prepared glass samples have been determined and calculated (density, volume molar, refraction index, Optical dielectric constant, molar refractivity and electronic polarizability) for glasses prepared.

Spectroscopic properties of lithium borate glass containing Sm3+ and Nd3+ ions

<p><span>Lithium borate glass samples mixed with a different concentration of Sm³+ and Nd³⁺ ions organized by quenching technique. Structural, vibration groups and spectral properties of glass samples investigated using X-ray diffraction, FTIR, UV/Vis/NIR and photoluminescence spectroscopy. The X-ray confirmed the lithium borate glass samples containing Sm³⁺ and Nd³⁺ ions in the amorphous state. Luminescence spectra of glass samples excited at 400 nm recorded, here three luminescence bands observed in Visible region, which due to spectra materials (Sm3+, Nd3+). These indicate that these glass samples responsible orange emission and used in the improvement of materials for LED, and optical devices. The functional vibration groups of the glass matrix studied using FTIR spectroscopy.</span></p>