Judd–Ofelt and luminescence properties of Dysprosium and Terbium doped bismuth-borate glass system

Abstract

AbstractAbsorption spectra of Tb3+ ions from the ground state 7F6 revealed three absorption bands. In addition to the six absorption bands for Dy3+ ions observed in the visible and near-infrared ranges. The optical band gape of sample free from Dy2O3 (4 mol% Tb4O7) smaller than other samples containing Dy2O3. The oscillator strengths and Judd–Ofelt parameters (Ω2, Ω4, Ω6) for reported Dy3+ and Tb3+ absorption transitions are estimated, and they do not follow a same trend depend on the substitution between Dy and Tb. The photoluminescence excitation of the Dy3+ at λem = 575 nm reveals the presence of a Tb3+ peak at 375 nm. The emission spectra of the glasses show that only the λem = 575 nm increases due to the excitation of the Tb3+ at λem = 545 nm, indicating effective energy transfer (ET) from the Tb3+ to Dy3+ in sample containing Dy2O3 up to 2 mol% and then changed from the Dy3+ to Tb3+. An efficient yellow luminescence arises from the activator's emitting centers. ET predicts the sensitizer's luminescence degradation and the activator's luminescence growth. The color coordinates and the correlated color temperature (CCT) indicate that the glass samples are suitable for white, yellow-green, and blue-light emission depend on the energy of excitation.