Effect of Pr3+ ions concentration on the spectroscopic properties of Zinc telluro-fluoroborate glasses for laser and optical amplifier applications

Abstract

A new series of Pr3+ ions doped Zinc telluro-fluoroborate (PrZTFB) glasses have been prepared by adding up to 2wt% Pr2O3. Spectroscopic properties were explored through X-ray diffraction, Raman, optical absorption, photoluminescence and decay measurements. The Raman spectra reveal the presence of different vibrational bonds of the borate and tellurite network(s). The bonding parameters have shown the ionic nature of the bonding Pr–X (X=O,F). The optical band gap energy and Urbach energy have been determined to understand the electronic band structure. The Judd-Ofelt parameters Ωλ (λ=2, 4 and 6) have been calculated to explore the bonding environment around the Pr3+ ions. The luminescence spectra exhibit emission bands in the visible region attributed to the 3P0→3H4, 3F2, 3F3, 3F4 and 3P1→3H5 and 1D2→3H4, 3H5 transitions and a broad near infrared emission band at around 1330nm corresponding to the 1G4→3H5 transition with a FWHM ≈70nm. The glasses lying in the reddish orange region of CIE 1931 chromaticity diagram have been found suitable for light emitting diode applications. The decay curves of 3P0 and 1D2 levels of Pr3+ exhibit non exponential behavior for all the glasses and experimental lifetime value is found to decrease while increasing the Pr3+ ions due to cross-relaxation mechanisms. The radiative parameters corresponding to the prominent 3P0→3H4, 1D2→3H4 and 1G4→3H5 emission transitions have been determined to elucidate the suitability of the studied glasses for the fabrication of photonic devices that includes laser materials and broad band optical amplifiers.