Vol. 42, Issue 2, pp. 365-379 (2012)

Abstract

A series of the Tb- and Dy-doped glasses with Li₂O–2B₂O₃ (or Li₂B₄O₇:Tb and Li₂B₄O₇:Dy) composition were synthesised and their spectroscopic properties were investigated. The Li₂B₄O₇:Tb and Li₂B₄O₇:Dy glasses of high chemical purity and optical quality were obtained from corresponding polycrystalline compounds in the air using standard glass technology. The Tb and Dy impurities were added to Li₂B₄O₇ composition in the form of Tb₂O₃ and Dy₂O₃ oxide compounds in amounts of 0.5 and 1.0 mol%. The electron paramagnetic resonance (EPR), luminescence excitation and emission spectra of the Li₂B₄O₇:Tb and Li₂B₄O₇:Dy glasses were investigated. On the basis of EPR and photoluminescence spectra analysis it was shown that the Tb and Dy impurities are incorporated in the Li₂B₄O₇ glass network as Tb³⁺ (4f⁸, ⁷F₆) and Dy³⁺ (4f⁹, ⁶H_15/2) ions, exclusively. All observed transitions of the Tb³⁺ and Dy³⁺ centres in the luminescence excitation and emission spectra were identified. The luminescence kinetics shows single exponential decay for Tb³⁺ and Dy³⁺ centres in Li₂B₄O₇ glasses. The lifetime values for main emission transitions of the Tb³⁺ and Dy³⁺ centres in the Li₂B₄O₇ glasses containing 0.5 and 1.0 mol% Tb₂O₃ and Dy₂O₃ are determined at T = 300 K. Peculiarities of optical properties and local structure of the Tb³⁺ and Dy³⁺ centres in the Li₂B₄O₇:Tb and Li₂B₄O₇:Dy glasses as well as their potential applications have been discussed.