Excited-state properties of newly sensitized imidazole-arylamine-based organic DSSC sensitizers in solvent and adsorbed on TiO<inf>2</inf>/FTO support

Six recently synthesized arylamine-imidazole combo dyes, utilized in dye-sensitized solar cells staining TiO2 semiconductor, were spectroscopically investigated. Studies were performed with application of steady-state and time-resolved absorption spectroscopies and were done on dyes dissolved in dichloromethane and anchored on TiO2/FTO film support. The investigations allowed to characterize the excited state decay dynamics of individual compounds, determine time constants of dye-to-TiO2 electron injection process for dyes adsorbed on TiO2/FTO support and subsequent recombination and dye regeneration dynamics. These studies were performed on bare dye/TiO2/FTO photoanodes in air environment and, if possible, on the same samples with dye layer immersed in electrolyte solution. These evaluations allowed to determine approximate time constants for dye regeneration and directed toward dye that reveals most advantageous properties and hypothetically should outperform its counterparts as TiO2 sensitizer.