Síntese e caracterização de filmes de Polipirrol dopados com Tetraquis(4-carboxifenil) porfirina para aplicações fotoelectroquímicas

Abstract

Photoelectrochemistry is emerging as a promising technology for harvesting and utilizing solar energy in a wide range of applications. However, electrode materials still need to be improved to achieve optimal performance. Conductive polymers emerge as particularly promising organic compounds for this purpose due to their highly versatile properties. In this study, the galvanostatic synthesis of polypyrrole films co-doped with tetrakis(4-carboxyphenyl) porphyrin (PPy/TCPP) on fluorine doped tin oxide (FTO)-coated glass substrates was performed for the first time. In addition, an evaluation of these films as photoelectrodes was performed, focusing on key properties. The incorporation of porphyrin into the polymer matrix was confirmed by UV-Vis and IR characterization. SEM micrographs showed the morphological changes induced by the codopant. Cyclovoltammetry was used to evaluate the conductivity of the film, its electroactivity, electroactive area and HOMO energy level. The chopped chronoamperometry confirmed the photoactivity of the material and its stability for 3000 s. The electrical and optical properties of the polymer were characterized by EIS and light absorption measurements to propose its energy level diagram. The PPy/TCPP coatings were obtained with high homogeneity on FTO, good conductivity, quasi-reversible electrochemical activity to ferrocene probe and stable photoactivity. Electrical characterization indicates high charge flow under illumination. An indirect bandgap of 2.51 eV and a HOMO level value of -4.59 eV were obtained for PPy/TCPP.