Anomalous Photoluminescence Behavior and Judd-Ofelt Analysis of Erbium-Barium Borate Glass Embedded with Copper Oxide Nanoclusters

Glasses doped with rare earth elements have been extensively researched for the purpose of creating novel and effective photonic devices. The impact of the LSPR of metallic nanoparticles on rare earth-doped glass for manipulating luminescent properties is a new matter of study. As a result, the localized surface plasmon resonance (LSPR) of metallic nanoparticles (NPs) in amorphous materials may create new opportunities in the disciplines of optics and photonics. Therefore, erbium-barium borate glasses with a 60B2O3-38.5BaO-1.5Er2O3-xCu2O-xSnO (x = 0, 1, 2, 3, 4, 5 mol%) composition were synthesized by the melt quenching technique. The synthesized glasses were then preliminarily subjected to HR-TEM, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopic analysis for structural investigation. A consistent linear trend was observed for Cu2O concentrations from 1 to 4 mol%, but a remarkable nonlinear anomaly emerged beyond the threshold concentration of 5 mol% Cu2O. This inflection point played a pivotal role, leading to the formation of Cu0, as confirmed by LSPR in UV-visible spectroscopy, significantly impacting the glass properties. Spectroscopic attributes, including branching ratio and stimulated emission cross section, underwent notable changes, particularly at 5 mol%, showcasing enhanced branching from 13.17 to 19.20% and quantum efficiency from 28.91 to 36%, positioning BEC5 as a promising candidate. The incorporation of copper nanoparticles up to the optimized threshold level allowed for the customization of overall glass attributes. Also, a discernible shift observed in chromaticity coordinates from green to yellow region draws attention to tunable display application. The current study intends to improve the understanding of the interactions between the compositional, structural, and optical properties of copper oxideembedded erbium-barium borate glasses for photonic and lasing applications.