Novel pyrrole-based dyes for dye-sensitized solar cells: From rod-shape to "H'' type

A series of "H'' type dye sensitizers with pyrrole as the conjugated bridge were synthesized, in which two pieces of N-arylpyrrole-based organic dye moieties were linked together through various aromatic rings. Interestingly, the introduced aromatic isolation group not only gave a new possibility to modify the construction structure, but also controlled the topological structure of the resultant dyes in some degree. As a result, their performance could be adjusted, and the configuration of "H''-type could suppress the aggregations on the TiO2 surface. The performance of the DSCs based on these dyes as the sensitizers demonstrated that the structure of these dyes was beneficial to the devices, and the conversion efficiency of the solar cell based on dye LI-22 with carbazole as the isolation group was as high as 5.22%.