Luminescence and spectroscopic studies on Eu3+-doped borate and boro-phosphate glasses for solid state optical devices

An addition of Eu3+ ions in Borate glasses (7TiO2 + 3Al2O3 + (60-x)B2O3 + xEu2O3 + 5LiCO3 + 25SrCO3) (where x = 0.05, 0.10, 0.15, and 0.20 mol%) and Boro-phosphate glasses (40B2O3 + 3Al2O3 + (10-x)P2O5 + xEu2O3 + 7ZnO + 5LiCO3 + 10H6NO4P + 25SrCO3) (where x = 0.10 and 0.20 mol%) containing heavy metals, alkali, and alkaline were prepared using a conventional melt quenching technique. The complementary study of the FT-IR and FT-Raman spectroscopic studies proposed the conversion of BO3 ⇔ BO4 in the borate glass network, and the exchange of the PO3 ⇔ PO2 in the boro-phosphate glass network by increasing the Eu3+ ion concentration. The optical characteristics including absorption, linear refractive index (n), Urbach energy (Eu), direct and indirect band gap energies of the prepared glasses were examined and discussed. Judd-Ofelt (JO) theory was used to determine radiative spectroscopic properties such as radiative transition probability (AR), luminescence branching ratio (& beta;R) and stimulated emission cross-section (& sigma;PE). Theoretically, the optical gain parameter and gain bandwidth were calculated, which shows their vital role in laser applications. Using CIE chromaticity coordinates, the reddish orange light emission was observed as a proportion of the increase in Eu3+ ions concentration in both glass networks. The measured colour coordinates were utilised to evaluate the correlated colour temperature (CCT), colour purity (Pc), and excitation purity (Pe) of the studied glasses.