Structural, dielectric, optical and photoluminescence studies of Tm3+ doped B2O3-BaO-MgO-Li2O-Na2O-LiF glasses featuring strong blue emission

Abstract

A series of Tm3+ doped lithium sodium barium borate glasses with following matrix compositions (50-x) B2O3-10BaO-10MgO-10Li2O-10Na2O-10LiF-xTm2O3 (x=0.25, 0.5, 1.0 and 1.5 mol %) were prepared by melt-quenching technique. The structural, dielectric, optical and luminescence properties of the glasses were studied. FTIR study shows the presence of various vibrational bands and the number of bridging (N4) and non-bridging (N3) oxygens were calculated from the deconvoluted FTIR spectra. The frequency and temperature dependent dielectric properties were analyzed in the frequency range 1Hz-1MHz and the temperature ranges 50 - 400 °C. The UV-Visible-NIR spectrum of the glasses showed the presence of five transition peaks emerging from the ground state (3H6) of Tm3+ ions. Bonding parameter showed the ionic nature exists between Tm3+ ions and its neighbouring ligands. Judd-Ofelt parameters were calculated following the same trend as Ω2 >Ω6> Ω4 for all the prepared glasses. The emission spectra of the glasses were recorded in the visible region and exhibited a strong blue emission at 454 nm from the level 1D2 → 3F4. Also, the prepared glasses have high experimental branching ratio value (~0.9) which suggests that the prepared glasses can be used for blue laser application. Commission Internationale de I'Eclairage (CIE) coordinates and color correlated temperature (CCT) values (~1500K) supported the application of the glasses for cool blue solid-state lighting.