Li2OLiFZnF2B2O3P2O5: MnO glasses – Thermal, structural, optical and luminescence characteristics

•Melt quench technique is employed in the preparation of Lithium fluoro-borophosphate glasses with and without MnO.•Glass stability of LZBP glass has increased with increase in MnO concentration.•The formation of stable POB, POMn and BOMn units are analysed from FTIR and Raman profiles.•The local symmetry of Mn2+ in the host matrix has been understood from crystal field strength (Dq), Racah (B & C) parameters.•Octahedral coordination of Mn2+ ions is estimated from the position of emission spectrum in the luminescence spectra.

Here, we present results pertaining to thermal, structural, optical and photoluminescence properties of Li2OLiFZnF2B2O3P2O5: (0.1–1.5 mol.%) MnO glasses. DTA profiles revealed a change in glass transition temperature with the addition of MnO suggesting an increase in glass stability. The modifications in structural units are interpreted from FTIR and Raman spectral profiles, which confirm the formation of stable POB bonds. The host Li2OLiFZnF2B2O3P2O5 (labelled as LZBP) glass exhibits emission in the blue region on excitation with 361 nm. The red shift in optical absorption edge and decrease in energy of band gap as a function of MnO concentration is analysed from Tauc’s plot. The nature of local symmetry around manganese ions in LZBP matrix has been understood by evaluating the crystal field strength (Dq) and Racah inter-electronic repulsion parameters (B & C) from absorption spectrum and electron-lattice interaction energy (Sħω) factor from emission spectrum. The emission spectra of (0.1–1.5 mol.%) Mn2+: LZPB glasses have shown broad band at 613 nm assigned to electronic transition 4T1g(G) → 6A1g(S) displaying orange-red emission upon excitation at 413 nm. Octahedral coordination of Mn2+ ions has been estimated from the position of emission in luminescence spectra. The effect of Mn2+ concentration on emission properties has been discussed from lifetime curves and energy level scheme.