Structural and Optical Characterization of Polymer based TiO_2 films for Photovoltaic Applications

摘要

The demand for energy worldwide is rising almost on a daily basis. There is need to research on new materials and ways to provide energy. In this preliminary study, we explore the properties of polymer based TiO_2 films for possible photovoltaic applications. TiO_2 films incorporating Polyvinylidene Fluoride-Co-Hexa fluoropropylene (PVDF-HFP) as the structure directing polymer and using Titanium lsopropoxide as the precursor were deposited by both dipping and spin coating techniques. The films were optimized with respect to solution concentration, and spin coater speeds as well as dip coating with drawl speed. X-Ray diffraction (XRD) structural, as well as transmittance studies were carried out. XRD spectra showed crystalline anatase films with crystal sizes of about 18-24 nm after annealing at about 430±50 °C for 30 minutes. The as deposited films were amorphous. For spin coated films, the films uniformity became better with spin speed. However, the optimum speed that ensures uniformity and lack of pin holes was found to be about 3000 RPM The transmittance of the films decreased with the coater speed. As for the dip coated films the concentration of the solution and the withdrawal speed affect the film thickness and therefore the transmittance of the films. Thicker films were obtained from more concentrated solutions. Decrease in concentration of the solution tended to produce a minimum thickness at some withdrawal speed. It was found that higher withdrawal speeds led to lower transmittance due to thicker films.