Organic Dyes Incorporating the Dithieno[3,2-b:2′,3′-d]thiophene Moiety for Efficient Dye-Sensitized Solar Cells.

New dipolar compounds incorporating a dithieno[3,2-b:2′,3′-d]thiophene unit as the electron donor, an oligothiophene moiety as the conjugated spacer, and 2-cyanoacrylic acid as the electron acceptor have been synthesized. These nonarylamine type metal-free organic compounds have been successfully used as the sensitizers of dye-sensitized solar cells (DSSCs). The conversion efficiencies of the DSSCs range from 3.54 to 5.15% under AM 1.5 G irradiation. The best efficiency reached ∼70% of the ruthenium dye N719-based standard cell fabricated and measured under similar conditions. [ABSTRACT FROM AUTHOR]