Concentration dependent photoluminescence studies of Dy~(3+) doped Bismuth Boro-Tellurite glasses for lasers and wLEDs

摘要

Bismuth Boro-Tellurite (BiBT) glasses activated with dysprosium ions were propitiously fabricated using melt quench method to study the luminescent potentiality using spectroscopic techniques such as FT-IR, absorption, photoluminescence (PL) excitation, PL emission and PL lifetime spectral recordings. FT-IR studies reveal various functional groups present in the titled glasses. The experimental oscillator strengths measured from the absorption spectral features are subjected to Judd-Ofelt (J-O) theory to estimate radiative properties of the Dy3+ ions in BiBT glasses. The excitation spectrum recorded for 1 mol% of Dy3+ ions in BiBT glass in the range 340-500 nm show six excitation bands with an intense one at 452 nm. The PL spectra recorded under 452 nm intense excitation wavelength displays three principal characteristic bands in blue, yellow and red regions and quenching was observed at 1 mol% of Dy3+ ions. The experimental lifetimes are found to be decreasing gradually with increase in Dy3+ ion concentration. The Inokuti-Hirayama model applied to the higher content of Dy3+ ions in BiBT glasses reveals dipole-dipole nature of interaction responsible for non-exponential nature as well as decrease in experimental lifetimes. The emission spectral information has been subjected to colorimetric analysis to evaluate CIE coordinates, CCT values and Y/B intensity ratio to have a look at the aptness of the titled glasses for white LEDs. The emission cross-section, branching ratios, quantum efficiency, CIE coordinates and CCT values evaluated finally reveals the superior nature of the BiBT glasses for various optoelectronic devices applications.