Fluorenylvinylenes bridged triphenylamine-based dyes with enhanced performance in dye-sensitized solar cells

We have synthesized a series of new dipolar organic dyes Bn (n=0, 1, 2) employing triarylamine as the electron-donor, 2-cyanoacrylic acid as the electron-acceptor, and fluorenevinylene as the conjugated bridge, which were used as sensitizers in dye-sensitized solar cells. It is found that the solar-energy-to-electricity conversion efficiencies of the prepared DSSCs are in the range of 2.79-5.56%, which reach 35-70% of a standard device based on N719 fabricated and measured under the same conditions. The DSSC sensitized with B1 with balanced length of conjugated bridge shows the highest photo-to-electrical energy conversion efficiency and the open-circuit photovoltage (V_oc) of 0.86 V.