Enhanced PEC characteristics of pre-annealed CuS film electrodes by metalloporphyrin/polymer matrices
Résumé
High conversion efficiency (η) values have been obtained from modified CuS film electrodes electrochemically deposited onto Glass/FTO. The modification involved pre-annealing the film followed by coating with tetra(-4-pyridyl)porphyrinato manganese (MnTPyP+) ions embedded inside a polyethylene (PE) matrix. The Glass/FTO/CuS/MnTPyP/PE electrodes exhibited enhanced photo-electrochemical (PEC) characteristics under solar simulated illumination (5.6 mW/cm−2) in aqueous media, compared to the as-prepared Glass/FTO/CuS films which showed no PEC activity. Up to 17.4% efficiency and 85% fill factor (FF) values were obtained from the modified film electrodes. Such characteristics have not been widely known for metal chalcogenide based film electrodes before. Different pre-annealing temperatures were attempted and the 250 °C temperature, followed by quenching, showed favorable results. Different aqueous redox couples were studied and the environmentally safe FeCl2/FeCl3 aqueous system showed highest PEC characteristics. Effect of pre-annealing on film electrode characteristics is discussed. The MnTPyP/PE matrix behaves as charge transfer catalyst for the holes across the CuS film/liquid junction.