Characterization of SnO₂ Nanoparticulate Film

A film was found to be formed at the air-SnO₂ hydrosol interface only by aging the hydrosol in air by Brewster Angle Microscopy technique. Development of surface pressure with aging time showed that the film took 500min to be formed completely. The films aged for different time were transferred onto different substrates such as CaF₂, silicon, mica and copper grid （400 mesh ） etc. by LB transfer device. The transferred films were characterized by UV-Vis spectroscopy, X-Ray photoelectron spectroscopy, Ellipsometry, TEM and AFM techniques. The results show: The film was SnO₂ nanoparticulate film exactly. The film transferred by vertical mode was better than that transferred by horizontal mode. The film aged for sh and transferred by vertical mode was uniform and compact. The thickness of the film was about 20 nm. The nanoparticles in the film were non-stoichiometry caused by oxygen deficiency. The film was stable in short time and then the nanoparticles in the film gathered gradually with the time going.