Successful Nd3+ Doping of Li2O–B2O3–Al2O3 Vitreous System: Optical Characterization and Judd–Ofelt Spectroscopic Calculations

Abstract

This study reports on the synthesis and the physical characterization of a ternary boron-rich (B-rich) lithium–boron–aluminum (LBA: Li2O–B2O3–Al2O3) vitreous system successfully doped with increasing Nd2O3 content (xNd2O3:LBA) in the range 0 ≤ x ≤ 5 wt %. The as-produced samples were investigated using optical absorption, photoluminescence emission, Raman spectroscopy, and differential thermal analysis. The Judd–Ofelt (JO) theory was used to assess the intensity parameters (Ω λ ), transition probabilities (A(J, J')), branch ratios (β), emission cross-sections (σ), quantum efficiencies (Y), experimental (τ exp ) and calculated (τ rad ) radiative lifetimes, and the spectroscopic quality values (χ = Ω 4/Ω 6) as a function of the nominal Nd2O3 doping content. Over the range of our investigation (0 ≤ x ≤ 5 wt %), we found that the Ω 2 and Ω 6JO parameters monotonically increased from 0.17 to 1.26 × 10−20 and from 1.19 to 1.84 × 10−20, respectively. In contrast, over the same range of nominal Nd2O3 doping content we found that the Ω 4 JO parameter decreased monotonically from 4.12 to 2.05 × 1 0−20. Although the τ exp values increased at the low end of nominal Nd2O3 content (up to 2.5 wt %), nonradiative energy transfer mechanisms (e.g., energy migration, cross-relaxation, and losses from networked phonons and O–H vibrational modes) governed the process at the high end of the nominal Nd2O3 content. A competition mechanism was proposed to explain the observed behavior in the 4F3/2 ⟶ 4IJ’transition lifetime for hosted Nd3+ ions.