Synthesis, structure and properties of silver tellurite glasses

The present work is a continuation of our earlier investigations on synthesis of non-traditional tellurite glasses and study of their structure and properties. Several multicomponent glass compositions containing Ag₂O (15, 25 mol%) have been selected for investigations. The glasses obtained were homogeneous and colored depending on composition. Some physical characteristics (density, molar volume, oxygen molar volume and oxygen packing density) of the amorphous samples were estimated. By IR spectroscopy was found that the addition of Ag₂O, shifts the band 625–620 cm⁻¹ to lower frequencies, due to the creation of Te—NBO bonds, which confirm it's modifying role. XPS exhibited that the addition of Ag₂O leads to the appearance of Te³⁺ and Te⁰ valence states and TeO₃ structural units additional to the dominant Te⁴⁺ amount and TeO₄ units, respectively. Formation of small silver clusters, covered by Ag¹⁺ ions was supposed as well. The existing of bridging oxygen bonds, only which build up the amorphous network, were discovered. It was established by UV–vis that the absorption edge of the glasses varies from 350 nm to 450 mm and the addition of Ag₂O caused a red shifting of the cut-off. It was also found that the silver plasmon resonance band appeared about 400 nm. (paper)