Structural and optical studies of activated thin film and monolith nano-structure silica gel with different rare earth elements prepared by sol - gel techniques

摘要

Rare earth (Pr?3, Eu?3, Er?3 and Ho?3 ions) doped silica gel with different concentrations in the range 1-6% of each element, in the form of thin film and monolith materials have been studied by X-ray diffraction (XRD). The types of structural information obtainable have been compared in detail. The XRD spectra of ?-crystobalite are obtained for the two type of materials and even by doping with the four rare earth element (REEs) at higher sintering heat treatment temperature. The structure study revealed that the crystallite size of pure monolith nano-structure silica gel was about 20.9 nm sintered at 1200oC, which decreased to 12.1 nm by doping with 6% of holmium ions at the same temperature. Optical measurements of both type of materials were also studied and compared. The normal transmission and specular reflection were measured. The coarse and fine microstructures of the monolith and thin film prepared samples were depicted by transmission electron microscope (TEM), which revealed the presence of nano-structure scale in the prepared samples, confirming the data obtained from XRD.