Estudi de nous procediments de baix impacte ambiental per a l'obtenció de recobriments d'òxid de titani, i d'òxid de zinc

This project deals with the study of new processes for the preparation of TiO2 and ZnO thin films that allow to control the characteristics of the obtained deposits and simultaneously having a minimum environmental impact, thus adjusting to the precepts of Green Chemisty. To reach this objective, it is proposed to study two different accessible modifications to improve the Chemical bath Deposition (CBD) technique: 1. The use of microwave radiation to accelerate the rate of growth and the degree of crystallization of the oxide coatings produced by CBD. This modification has been prevouosly developed by our research group and the first results about the preparation of TiO2 thin films has been published elsewhere. After these promising results the present project plan to forward the development of this new technique, and its use to the production of other materials like ZnO and also, doped ZnO. The aim is to establish the experimental parameter that let thorough control of the properties of the coatings obtained: composition, adherence, morphology size and orientation of the particles structure and porosity. 2. Improvement of the CBD technique could also be achieved by the use of alternative solvents, since solvent being the most abundant component of the chemical bath, have a fundamental influence in the crystal growth processes. To do this we paln to assess the environmental impact of the different commercial solvents using specific data base, and considering the life cycle of the product. The key objective is to find low environmental impact solvents that favour the crystallization of titanium oxide and zinc oxide at low temperatures. In the present project we propose also the production of coating starting from pre-synthesized TiO2 and ZnO particles of colloidal or nanometric size. The particles will be deposited on the substrate from a suspension. These materials absorb light of wavelength lower than their band gap (...)