Down-conversion luminescence and shielding parameters of Dy3+: NFBT glass for white LED and radiation applications

Abstract

A new kind of dysprosium (Dy3+) ions doped niobium fluoro borotellurite (NFBT) glass with compositions (35- x )TeO2 + 30H3 BO3 + 15Nb2O5 + 10SrCO3 + 10CdF2 + x Dy 2O3 (where x = 0.05, 0.3, 0.5, 1, 2 and 3 in wt. %, hereafter refers as to Dy 3+ ions’ concentration) was fabricated with melt quenching method and characterized through X-ray diffraction, physical (density (ρ), molar volume of oxygen (V o), and optical basicity ( th), etc.), visible absorption, excitation, emission and lifetime measurements. Its density increases while its molar volume decreases with increase of Dy3+ ions, which indicates that the glass becomes more compact. The absorption spectrum shows the various characteristic peaks of Dy3+ ions attributed to the transitions from the 6H 15/2 ground level to the different excited energy levels. The oscillator strengths and Judd-Ofelt intensity parameters (W l =2, 4 & 6) were articulated from the optical absorption spectrum. The photoluminescence spectrum reveals that this NFBT glass has several emission bands, corresponding to 4F 9/2 → 6H 15/2 (blue), 4F 9/2 → 6H 13/2 (yellow) and 4F 9/2 → 6H 11/2 (red) transitions, respectively. The emission intensity increased with Dy3+ ions concentration from 0.05 wt. % to 1 wt. %, after that the concentration quenching was observed for higher concentrations (2 & 3 wt. %). The non-exponential decay curves were analysed with Inokuti-Hirayama (IH) model ( S =6), indicating a nature of dipoledipole interaction between the donor and the acceptor of Dy3+ ions. The Commission International de’Eclairage (CIE 1931 (x , y) and CIE 1976 ( u , v )) coordinates and the correlated color temperature (CCT) values clearly show that the present glass can be useful in cool white light (CCT>4000 K) region. Moreover, mass attenuation coefficient (μ / ρ), and effective atomic number (Z eff) parameters were also articulated through Phy-X/PSD program. Hence, the results indicate that the prepared glasses could be suitable for laser, smart white LED (1DyNFBT) and gamma ray shielding (3DyNFBT) applications. • A novel series of Dy 3+ : NFBT glasses were prepared with melt quenching. • Luminescence and colorimetric parameters (CIE, CP , CCT, Y/B ratio) were evaluated. • Gamma radiation shielding parameters (MAC, HVL, MFP, Ʃ R , Z eff , etc.) were analysed. • 1DyNFBT and 3DyNFBT glasses can be suggested for WLED and gamma ray shielding applications.