Judd–Ofelt and luminescence properties of Dysprosium and Terbium doped bismuth-borate glass system
A. Ratep, I. Kashif
Abstract
Abstract Absorption spectra of Tb 3+ ions from the ground state 7 F 6 revealed three absorption bands. In addition to the six absorption bands for Dy 3+ ions observed in the visible and near-infrared ranges. The optical band gape of sample free from Dy 2 O 3 (4 mol% Tb 4 O 7 ) smaller than other samples containing Dy 2 O 3 . The oscillator strengths and Judd–Ofelt parameters (Ω 2 , Ω 4 , Ω 6 ) for reported Dy 3+ and Tb 3+ 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 Dy 3+ at λ em = 575 nm reveals the presence of a Tb 3+ peak at 375 nm. The emission spectra of the glasses show that only the λ em = 575 nm increases due to the excitation of the Tb 3+ at λ em = 545 nm, indicating effective energy transfer (ET) from the Tb 3+ to Dy 3+ in sample containing Dy 2 O 3 up to 2 mol% and then changed from the Dy 3+ to Tb 3+ . 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.