Ellipsometry porosimetry: fast and nondestructive technique to characterize porosity of cubic mesoporous TiO2 thin films

Crystalline TiO2 (Anatase configuration) thin films is widely used in the photocatalysis and photovoltaic industries ((self cleaning surface and renewable energies for example). The synthesis of these films is obtained from a dispersed solution of molecular poorly condensed species using Sol-Gel and liquid deposition processes. It allows the introduction of organic molecules (porogenes) inside inorganic network to create what is called hybrid materials. Spectroscopic ellipsometry is the technique of choice to characterize thickness and refractive indices of such thin layers. The adsorption of water at atmospheric pressure within the pores, modifies the refractive index of the layer. The change in refractive index induced by the introduction of water is measured by ellipsometry. A Lorentz Lorenz effective medium model is used to calculate the volume of water adsorbed by the material. Atmospheric Ellipsometric porosimetry (EPA) measurements become an effective method for characterization of porosity, pore size distribution (PSD), average pore size, Cumulative surface area and Young's modulus of porous films. EP is also suitable to evaluate the sealing of a porous layer.. EP evaluates the change in refractive index due to the penetration of the solvent through the sealing layer into the porous layer. In this paper, the instrument as well as some examples will be presented the abstract two lines below author names and addresses.