Optical properties of Eu3+ & Tb3+ ions doped alkali oxide (Li2O/ Na2O/ K2O) modified boro phosphate glasses for red, green lasers and display device applications

In this article we report on alkali oxide modified borophosphate glasses doped with Eu³⁺and Tb³⁺ ions, with the chemical composition of 69.5 B₂O₃+10P₂O₅ + 10CaF₂ + 5 Li₂O+ 5ZnO+ R+ 0.5 Eu₂O₃ [where R = 5 (LiO₂/Na₂O/K₂O)] have been prepared by conventional melt quenching technique, and the spectroscopic properties of the prepared glasses have been studied by XRD, Optical absorption, excitation and emission spectral analysis. XRD spectrum of the glasses have shown the amorphous nature of the glasses. The red emission corresponding to ⁵D₀ → ⁷F₂ (613 nm) transition was observed under the excitation of 394 nm wavelength, corresponding to Eu³⁺ ions, for all the prepared glasses. For Eu³⁺ ion doped glasses, emission bands were observed, such as; ⁵D₁→ ⁷F₁ (538 nm), ⁵D₀→ ⁷F₀ (580 nm), ⁵D₀→ ⁷F₁ (592 nm), ⁵D₀→ ⁷F₂ (613 nm), ⁵D₀→ ⁷F₃ (613 nm) and ⁵D₀→ ⁷F₄ (702 nm) are identified. In the case of Tb³⁺ ion doped glasses, four emission lines were observed, such as ⁵D₄→ (⁷F₆, ⁷F₅, ⁷F₄), which are located at 489 nm, 545 nm and 585 nm, respectively, after the samples were excited with 376 nm ultraviolet source. The green emission corresponding to ⁵D₄ → ⁷F₅ (543 nm) transition was observed under excitation wavelength 376 nm of the Tb³⁺ ions for all the prepared glasses. For all these emission bands, the decay curves were recorded to evaluate the emission life times. The mechanism underlying the observed emission from the glasses was explained in terms of energy levels.