Amine functionalized homoleptic ruthenium(II) sensitizer for dye‐sensitized solar cells: A combined effect of ancillary ligands and co‐sensitization

Abstract

In this work, we propose a homoleptic ruthenium(II) complex, [Ru(dabpy)3]Cl2 (RDAB3) containing amine functionalized electron donating anchoring units for DSSCs. The DSSCs were co-sensitized by coumarin-based thiophene (CT) and indole (CI) units. The presence of four ancillary amine groups in RDAB3 influences its photovoltaic performance and the introduction of coumarin-based co-sensitizers significantly enhances the efficiency. The fabricated DSSCs were explored by UV-Visible absorption, photocurrent-voltage assessments, and impedance spectral studies. Co-sensitized DSSCs showed an improved photovoltaic efficiency than the device sensitized by RDAB3 alone. Under optimized condition, the device made up of RDAB3+CI exhibited a high Jsc = 9.9 mA/cm2 with Voc of 0.7 V, fill factor of 0.773, and solar to power conversion efficiency of 5.35% in standard global AM 1.5 solar irradiation. This performance is found to be higher than the DSSC sensitized with RDAB3 (η = 3.84%) fabricated under same circumstances.