Configuration modifications of π-spacer and their hypothetical effect on indolo [3, 2, 1-jk] carbazole-based DSSCs performance

In this study, a π-spacer modification technique was employed on indolo[3,2,1-jk] carbazole-based donor materials with a cyanoacrylic acid group as the acceptor to design nine new molecules. The π-spacer modification on the indolo[3,2,1-jk] carbazole-based donor materials offer advantages in improving DSSCs efficiency and optoelectrical behavior. The newly designed molecules were examined for several crucial parameters, including absorbance maximum, frontier molecular orbitals, excitation energy, light harvesting efficiency, Voc, and fill factor. All of the designed dyes significantly improved their optical and performance-related characteristics. Among the studied molecules, IC2, which featured an additional furan π-bridge with an ethyl group and a double furan ring around the azo group, displayed the broadest range of UV-Vis peak absorbance (547 nm) with the lowest energy of excitation (2.26 eV). Furthermore, the molecules with extended furan π-bridges exhibited high values of light harvesting ability, while those with pyrrole π-bridges, such as IC9, showed the highest open-circuit voltage (2.81V). Depending on these favorable properties, the molecules with additional π-bridges are considered promising candidates for DSSCs.