Enhanced red emission of Gd\(_{2}\)MoO\(_{6}\):Eu\(^{3+}\) phosphor-in-glass embedded in SiO\(_{2}\)-TeO\(_{2}\)-Na\(_{2}\)O-BaO matrix for solid-state lighting

Abstract

Gd₂MoO₆:Eu³⁺ phosphor-in-glass (PIG) composites were synthesized by a microwave-assisted melting technique using a 50SiO₂:20TeO₂:15Na₂O:15BaO glass matrix containing 0.00 wt% to 10.00 wt% phosphor. Their structural, optical, and luminescent properties were systematically investigated. X-ray diffraction confirmed the formation of crystalline Gd₂MoO₆ phases, which became prominent at 5.00 wt% and 10.00 wt%, indicating partial crystallization within the glass network. The density and refractive index increased from 3.621 g∙cm^‒3 to 3.774 g∙cm^‒3 and 1.535 to 1.692 with higher phosphor loading, suggesting a more compact structure. Absorption spectra showed four characteristic Eu³⁺ bands at 464 nm, 534 nm, 2088 nm, and 2203 nm, while excitation monitored at 613 nm exhibited the strongest band at 394 nm (⁷F₀→⁵L₆). Emission spectra revealed intense red emissions at 590 nm, 613 nm, 653 nm, and 702 nm, corresponding to the ⁵D₀→⁷F₁–⁷F₅ transitions, with chromaticity coordinates of (x, y) = (0.65, 0.34). The photoluminescence lifetime, measured under 394 nm excitation and monitored at 613 nm emission, decreased slightly from 1.719 ms to 1.585 ms. Vickers hardness values measured under a 0.2 kgf load ranged from 1601.7 HV0.2 to 1606.1 HV0.2, indicating high mechanical durability. Overall, the obtained PIG composites show strong red emission and robust structural properties, demonstrating their potential for solid-state lighting applications.