Structure and optical properties of chalcohalide glasses doped with Pr3+ and Yb3+ ions

Glasses of systems 100-y((GeS2)80(Sb2S3)20−x(PbI2)x)yPr2S3, x = 0; 2; 5, 8; y = 0; 0.01; 0.1; 0.5 and 99.9-z((GeS2)80(Sb2S3)18(PbI2)2)0.1Pr2S3zYb2S3, z = 0.05; 0.1; 0.15) were synthesized in high purity. Optically well transparent glasses were obtained for x ⩽ 5 mol.% PbI2, for y ⩽ 0.1 mol.% Pr2S3 and for z ⩽ 0.15 mol.% Yb2S3. The glasses were stable and homogeneous, as confirmed by X-ray diffraction and electron microscopy, with high optical transmittivity from visible (red) region up to infrared region (∼900 cm−1). The density of the glasses was 3.26–3.33 gcm−3 for PbI2 containing glasses. The glass transition temperature, Tg, was ∼320–336 °C. The optical absorption bands in rare-earth doped glasses corresponded to 3H4–3F4, 3H4–3F3, 3H4–(3F2 + 3H6) f–f electron transitions of Pr3+ ions and to 2F7/2–2F5/2 f–f electron transitions of Yb3+ ions. Strong luminescence band with maximum near 1340 nm (electron transition 1G4–3H5) was found in Pr2S3 doped glasses. The intensity of this band was rising with doping by Yb3+ ions. The possible mechanism of the luminescence enhancement is suggested.