Physicochemical study of synthetic dyes adsorption on TiO2 thin films for dye sensitized solar cells

In this work we study equilibrium and kinetic adsorption process of Methylene Blue (MB) and Copper phthalocyanine (CuPhTh) dyes on TiO₂ thin films. We synthesized phthalocyanines through Achar method; dyes were characterized by Fourier-Transform Infrared spectroscopy (FTIR) and Diffuse reflectance. TiO₂ thin films were fabricated by Doctor Blade method for using Degussa P25 as TiO₂ source. We used Langmuir and Freundlich adsorption models to describe adsorption equilibrium, and besides, we used Largergren model to describe kinetic adsorption process. Characterization results reveal typical signals of phthalocyaninaes, and besides, TiO₂ thin films had a polycrystalline structure. Results indicated dyes adsorption to occur through chemisorption process and Langmuir adsorption model describes suitably dye adsorption process on TiO₂ thin films.