Deposition of TiO2 filmes via sol-gel-dip-coating through a method that uses two phases, and preparation of heterostructure with SnO2

Thin films posses a variety of applications in many fields and technologies and a multitude of methods to prepare such films for these applications. The sol-gel methods have as advantages its simplicity in the production of oxide films and a lower budget requirement for equipment, becoming interesting as deposition method for films in an industrial scale as well as in academic research. The goal of this work was to study the effects and possible advantages and disadvantages of dip-coating deposition via a two-phase system, applying this proposed method to prepare TiO2 films as well as heterostructures comprised of SnO2 and TiO2 as well as explore this method as a doping procedure. The existing literature developed around these materials is extensive and provides ample base from which to experiment with the proposed method. Aiming for the development of a deposition method that may allow for greater control of thin film properties, several parameters were varied such as: solvent choice, composition and concentration of material in phases, viscosity, pH, deposition speed, substrate, and others. The study of the effects of such method in the films electrical and morphological properties is new and results have shown an increased efficiency on the photocatalitical degradation of methylene blue, with draining regimen changing without a change in deposition speed. The investigation of TiO2 thin films doped with lanthanides has shown a control mechanism in the anatase-rutile transition as well as an increase in the Urbach energy related to intrabandgap states. The proposed deposition method aims to complement the conventional deposition method with a new array of parameters to further develop areas such as gas sensing, with better surface control, and transparent electronic devices, such as field effect transistors (FETs) and capacitors. (AU)