Synthesis and spectral-optical properties of composite materials based on high-silica porous glasses doped by iodides of silver and erbium

Composite materials (CMs) doped by iodides of silver and erbium were synthesized on the base of the thermally modified high-silica porous glasses (PGs) with small additions of P2O5 and fluoride ions. CMs were manufactured by two-stage impregnation of the PGs first with AgNO3 aqueous solution (with or without Er(NO3)3), next in the halide salt (0.6 M KI) aqueous solution. Then the samples of composites were heat treated at the temperatures from 120 to 870°C up to their sintering and closing of the pores. The structure of composites was studied by X-ray powder diffraction (XRD) technique. According to XRD data the CMs doped by iodides of silver and erbium contain the AgI phase. Spectral-optical properties of CMs were investigated by UV-VIS-NIR spectroscopy. Optical density spectra in UV-VIS region have the bands corresponded with the absorption of silver molecular clusters. Peaks at 377, 448, 450-453, 485, 611-622, 647, 668-684 nm answered to the absorption of erbium ions were found. According to NIR transmission spectra, bands caused by the absorption of Si-OH, B-OH and Na-OH groups are found.