Investigation of D-π-A organic dyes based on Quinoline for their applications in dye-sensitized solar cells

In this study, three novel D-π-A organic dyes containing quinoline (5a and 5b) and pyridocarbazole (5c) as the π-spacers have been used for dye-sensitized solar cells (DSSCs). The experimental and theoretical results confirmed that the incorporation of pyridocarbazole in the dye could be favorable for the long wavelength light-harvesting as compared to quinoline based dyes. Power conversion efficiency of DSSCs based on 5a-c dyes together with chenodeoxycholic acid (CDCA) is 2.39%, 2.62% and 3.25% respectively. However, these efficiencies present only 8–15% of enhancement compared to that in the absence of coadsorbent (CDCA), which suggests dyes 5a-c suppress the intermolecular aggregation and restrain charge recombination. In other words, this work suggests that the introduction of quinoline or pyridocarbazole as the π-spacers into D-π-A organic dyes is a promising way for coadsorbent-free DSSCs.