Comprehensive investigation of (Ce3+, Eu3+) codoped LiCaBiB glasses: physical, structural, and photoluminescence analyses

Abstract

Herein, we present the luminescence-emission properties of (Ce³⁺, Eu³⁺) doped Li₂O-CaO-Bi₂O₃-B₂O₃ glasses fabricated via melt-quenching. The density of glasses was found to increase from 3.551 to 3.655 g/cm³ with dopant concentration, owing to the formation of non-bridging oxygens, resulting in enhanced luminescence by facilitating radiative transitions of Eu³⁺-ions. On the other hand, slight decreases in molar volume, refractivity, polarizability, optical basicity, and electronic polarizability suggest a more localised charge distribution and reduced polarizability. nevertheless, the stability in reflection loss, dielectric constant, and transmission coefficient indicates consistent optical quality and stable glass material. Raman analysis reveals the structural changes induced by the dopants due to Bi-O bonds, B-O-B linkages, and BO₃ and BO₄ units. The excitation spectra revealed broad Ce³⁺ (300–350 nm) bands and sharp peaks for Eu³⁺ (393 and 464 nm), indicating distinct optical behaviours. Emission spectra showed broad Ce³⁺ emission (400–450 nm) and sharp Eu³⁺ emission (592 and 615 nm), highlighting effective energy transfer between Ce³⁺-Eu³⁺ ions and improved luminescent properties. Decay kinetics demonstrated increased lifetime values with higher Eu³⁺ concentrations under 328 nm excitation, and consistent lifetime values were observed under 394 nm excitation due to the interplay of energy transfer dynamics, quenching effects, and the availability of non-radiative decay channels influenced by Eu³⁺ concentration and excitation wavelength. Among the prepared glasses, the LCBBCe_0.1Eu_0.5 glass exhibits the highest emission intensity in the deep red region, with an emission purity of 98.3% when excited at 394 nm.