Color Tunable Emission of Y₃Al₅O₁₂:Ce³⁺ and Sm³⁺-Doped Zinc–Germanate–Tellurite Glass Nanocomposite Powders and Coatings for Light-Emitting Diodes Applications

A series of nanocomposite (NC) powders and coatings of ZnO–GeO₂–TeO₂:xSm³⁺ glass and Y₃Al₅O₁₂:Ce³⁺ nanoparticles (YAG:Ce) are fabricated. Samarium ions concentration of the glass phosphor is varied with x values of 0.3, 1.0, 3.0, and 5.0 mol%. The powder batches are prepared with a 95/5 mass ratio of glass/YAG:Ce and uniaxially pressed to obtain powder pellets that are heat-treated at 350 °C. Morphology and structural characterization are conducted through X-ray diffraction analysis, scanning electron microscopy, and Raman spectroscopy. The photoluminescence properties of NCs are investigated under different wavelengths of 340, 403, and 460 nm, showing a global emission tonality in the reddish-orange and yellowish-green region according to the estimated CIE 1931 chromaticity coordinates. Also, NC coatings soda–lime glass slides are fabricated, and their photoluminescence is characterized using an UV light-emitting chip (≈365 nm) and a blue light-emitting chip (≈460 nm). The global emission under UV and blue light from the light-emitting diode (LED) chips of the NC coatings shows a color tunability in the warm white light and yellowish-green region.