Organic Dyes Incorporating the Benzo[1,2-b:4,5-b′]dithiophene Moiety for Efficient Dye-Sensitized Solar Cells

A new class of organic sensitizers incorporating a benzo[1,2-b:4,5-b']dithlophene (BDT) unit as conjugated spacer has been synthesized and successfully used for dye-sensitized solar cells (DSSCs). The length of the pi-conjugated spacers has a strong impact on electro-optical properties of these dyes, leading to the conversion efficiencies ranging from 4.17 to 5.68% under AM 1.5 G irradiation. This result indicates that the BDT unit is a promising candidate in organic sensitizers.