A Novel Route For Preparation Of Transparent, Mechanically Robust And Photoactive Titania Films

Interest in titania based materials has grown in recent years owing to the potential application of TiO2 films in numerous fields like indoor and outdoor degradation of pollutants, self-cleaning surfaces, smart windows and antifogging mirrors [1-3]. In this respect, it is crucial to develop industrially viable preparation techniques for the preparation of active, mechanical robust and transparent TiO2 layers [4]. In this work, a simple and inexpensive electrochemically assisted procedure is presented to deposit transparent and mechanically robust TiO2 films on various kinds of substrates, both conductive and non-conductive (glass slides, metal laminas, optically transparent conductive oxides). The obtained films were characterized for their morphology and thickness by scanning electron microscopy (SEM). Moreover, the film optical, mechanical and electrochemical properties were characterized by diffuse reflectance spectroscopy (DRS), mechanical tests (Wolf Wilburn hardness and adhesion tests), and cyclic voltammetry, respectively. The obtained films were uniform, crack-free and exhibited excellent chemical, mechanical, and electrochemical robustness. The obtained layers were compared to films prepared by a routine preparation technique (dip coating), exhibiting significantly improved morphological, optical and conductive properties. The photo-activity of TiO2 was exploited to obtain transparent spectroelectrochemical systems and antifogging and self-cleaning surfaces. The photoelectrochemical properties of TiO2 films were exploited to fabricate a working Grätzel cell and to activate a photoelectrochemical polymerization of polypyrrole onto an un-conductive support. The presented stable and transparent TiO2 layers represent promising materials for numerous applications such as photocatalytic windows and coatings, antifogging mirrors, solar cells and optically transparent electrodes. With respect to classical commercial nano-powders, the present robust films reduce the health concerns associated with volatile nanostructured materials [5].