High-performance dye-sensitized solar cells based on 5,6-bis-hexyloxy-benzo[2,1,3]thiadiazole

New dipolar compounds containing a 5,6-bis-hexyloxy-benzo[2,1,3]thiadiazole entity in the conjugated spacer between the electron donating arylamine and the electron accepting 2-cyanoacrylic acid have been synthesized. These compounds were used as the sensitizers for efficient dye-sensitized solar cells. Compared to the congeners without the hexyloxy chains, the new dyes effectively suppress the dark currents and significantly improve the cell performance. The best conversion efficiency reached ∼92% of the N719-based standard DSSC fabricated and measured under similar conditions (AM 1.5 irradiation).