Structure-Property Relationship of New Organic Sensitizers Based on Multicarbazole Derivatives for Dye-Sensitized Solar Cells
A new multicarbazole based organic dye (C2A1,C2S1A1) with a twisted structure was designed and synthesized, and the corresponding dye (C1A1) without the twisted structure was synthesized for comparison. They were successfully applied in dye-sensitized solar cells (DSSCs). The results showed that the nonplanar structure ofC2A1andC2S1A1can efficiently retard the dye aggregation and charge recombination. The organic dye (C2S1A1) with thiophene units also exhibited a higher molar extinction coefficient and red-shifted absorption, which leads to an improved light harvesting efficiency. TheC2S1A1-sensitized solar cell produced a solar-to-electricity conversion efficiency of 5.1%, high open circuit voltage (Voc) of 0.69 V, and short-circuit photocurrent density of 10.83 mA cm−2under AM 1.5 irradiation (100 mW cm−2) conditions.