Structural, optical and electrical properties of Eu doped sodium borosilicate and lead silicate glasses

Abstract

Structural, electrical and luminescence properties of sodium borosilicate and sodium lead borosilicate glasses prepared by conventional melt quenching method were investigated through XRD, FT-IR, EDS, luminescence, and electrical measurements. All compositions were X-ray amorphous. The FT-IR analysis showed variations in the glass network upon changing the SiO₂ content in the compositions. Excitation spectra of glasses in both series consisted of several excitation peaks between 350 and 550 nm corresponding to 4f-4f transitions of Eu³⁺. The luminescence spectra of glasses in both series consist of peaks in the 560–700 nm interval corresponding to 4f-4f transitions of Eu³⁺ ($5D_0{⟶}^7{F}_j$). Increasing Na₂O content enhanced the DC conductivity in both sodium borosilicate and sodium lead borosilicate glass series. Sodium lead borosilicate glasses exhibited a linear relationship between Na ⁺ ion concentration and conductivity, with the highest value of 1.40 × 10⁻⁶ (Ω cm)⁻¹ at 150 °C for 40 mol% Na₂O. In contrast, sodium borosilicate glasses showed a non-linear trend which could be related to the mixed glass-former effect, with 30 mol% Na₂O exhibiting the highest conductivity of 2.55 × 10⁻⁸ (Ω cm)⁻¹ at 150 °C, highlighting the impact of structural changes on ion mobility. The scaling analysis confirmed that temperature influences charge carrier dynamics without changing the conduction mechanism. The characteristic hopping length of mobile ions decreased as Na₂O content increased, aligning with the observed trends in conductivity.