Er-doped antimonite Sb2O3 -PbO-ZnO/ZnS glasses studied by low-temperature photoluminescence spectroscopy

Antimonite glasses Sb2O3-PbO-ZnO/ZnS doped with ErCl3 within the range of 0.25-1.0 mol% were prepared and investigated by means of transmission, photoluminescence excitation and photoluminescence (PL) spectroscopy. In the studied glasses, the wavelength of 522 nm was found to be the most suitable for PL excitation of doped-in Er3+ ions in both the NIP and VIS spectral ranges. The PL spectra excited by wavelengths at 522 and/or 514.5 nm were measured at room and low temperatures (4 K) in the wavelength range of 400-1700 nm. Low-temperature PL spectroscopy allowed us to observe both the broad luminescence of the host glass centred at around 1050 nm and the narrow emissions caused by Er3+ ions. Special attention was given to the wavelengths where the broad-band luminescence of the host overlaps with 4f-4f transitions within Er3+ ions. A broad PL band of the host glass was observed together with a superimposed narrow emission band at 985 nm (I-4(11/2) -> I-4(15/2)) and a narrow absorption dip at about 970 nm ((4)(15/2)-> I-4(11/2)). This absorption dip is a direct experimental evidence of energy transfer from the electronic structure of the host glass to 4f states of doped-in Er3+ ions. The strongest PL band at 1530 nm, representing transition from the lowest excited manifold I-4(13/2) to the ground state manifold I-4(15/2) was measured at 300 K and 4 K. The broadening at elevated temperature occurs primarily in the high energy part of the spectrum due to thermal excitation of electrons within the I-4(13/2) manifold. (C) 2018 Elsevier B.V. All rights reserved.