Research On Composition, Structure And Properties Of Ge-Ga-S-(Pb,Cd)I₂ Chalcohalide Glass

Recently chalcohalide glasses have attracted much attention according to their possible applications as IR material. Because of the good glass-forming ability and large solubility of rare earth ions, Ge-Ga-S-based chalcohalide glasses attained extensive recognition. Based on the prevenient results, glass-forming ability, optical properties and so on are improved following the addition of heavy metal halides. So understanding and utilization of the basic studying findings about the heavy metal doped Ge-Ga-S-based chalcohalide glasses are worthwhile from theoretical and practical viewpoints.Utilizing the techniques such as X-Ray diffraction, Raman spectra, Comprehensive thermal analysis, SEM, EPMA, UV-Vis-Near IR and FTIR, and etc., probing and analysis had been made systematically about the relationships of composition, structure and properties within two pseudo-ternary systems: GeS₂-Ga₂S₃-CdI₂, GeS₂-Ga₂S₃-PbI₂. The obtained conclusions are as follows:The glass-forming regions within GeS₂-Ga₂S₃-Cd (Pb) I₂ systems that located in GeS₂-rich region were reported firstly. The better glass forming ability of GeS₂-Ga₂S₃-CdI₂ system was found compared to that of GeS₂-Ga₂S₃PbI₂. No distinct change about the glassy color was found following the addition of CdI₂ and PbI₂.The IR-cutoff edge of the GeS₂-Ga₂S₃-Cd (Pb) I₂ systems is located at about 12.8μm which is dominated by the stretching vibrating of Ge-S bonds. Within the GeS₂-Ga₂S₃-CdI₂ system, the shift about Urbach absorption edge was not found following the addition of CdI₂. However, within another GeS₂-Ga₂S₃-PbI₂ system, Red shift of Urbach absorption edge was found with the increasing amount of PbI₂.Within the two GeS₂-Ga₂S₃-Cd(Pb)I₂ glassy systems, the glass transition temperatures both vary in the range of 600K and 700K. After exposure in air for a long term, oxygenized and Iodine-poor regions were found. About the GeS₂-Ga₂S₃-PbI₂ system, the poor mechanical property was found.The microstructure of the GeS₂-Ga₂S₃-Cd I₂ glass was considered to be: the framework of the network consists of the [GeS₄] and [GaS₄] tetrahedral connected by bridged S; and the partial Sulfur was replaced by the Iodine as the net-terminator.With the addition of CdI₂, the density of the GeS₂-Ga₂S₃-CdI₂ glasses increase distinctly.