Synthesis and optical properties of the Ge–Sb–S:PrCl 3 glass system

Abstract

The (GeS 2) 80− x (Sb 2S 3) 20 · xPrCl 3 and (GeS 2) 60− x (Sb 2S 3) 40 · xPrCl 3, ( x=0.01, 0.1, 0.5) glass systems were prepared from elements and PrCl 3 by thermal synthesis. The glasses were of orange to red colour, they were optically homogeneous up to 0.5 mol% of PrCl 3, the samples with 1 mol% of PrCl 3 were partly crystalline. The homogeneity was confirmed by optical methods and by electron microscopy. The glass transition temperatures, T g, were between 330°C and 333°C for (GeS 2) 80− x (Sb 2S 3) 20 · xPrCl 3 glasses and between 256°C and 274°C for (GeS 2) 60− x (Sb 2S 3) 40− x · xPrCl 3 glasses, ( x=0.01, 0.1, 0.5). The short-wavelength absorption edge was between 550 and 700 nm for (GeS 2) 60− x (Sb 2S 3) 40 · xPrCl 3 glasses and between 500 and 650 nm for (GeS 2) 80− x (Sb 2S 3) 20 · xPrCl 3 glasses. The long-wavelength absorption edge was between 900 and 1000 cm −1 and is apparently caused by multiphonon absorption of Ge–S and Sb–S vibration modes. Doping with Pr 3+ ions creates new absorption bands near 2100, 4980, 6370, 6640 and 9843 cm −1, which are assigned to the electron transitions from the 3H 4 level of Pr 3+ to the 3H 5, 3H 6, 3F 2, 3F 3, 3F 4, 1G 4 levels, respectively, of the Pr 3+ ion. The absorption bands corresponding to 3H 4 → 3H 6, 3F 2 and to 3H 4 → 3F 3, 3F 4 transitions are overlapped. The Raman spectra were deconvoluted into several bands, which can be assigned as the vibrations of GeS 4, SbS 3 and S 8 structural units. The structure of these glasses can be described as interconnected GeS 4 tetrahedra and SbS 3 pyramids with dissolved S 8 molecules and Pr 3+ ions. The luminescence spectrum consisted of two luminescence bands. The one at ∼1300 nm, was assigned to 1G 4– 3H 5 electron transitions of the Pr 3+ ions. The other luminescence band of smaller amplitude was ∼1600 nm and assigned to transitions between the 3F 3 and 3H 4 electron levels of Pr 3+.