Rhodanine-3-acetic acid and π-extended tetrathiafulvalene (exTTF) based systems for dye-sensitized solar cells

Abstract

We report here the synthesis, electrochemical and photophysical properties of a series of novel exTTF-based organic dyes (3 and 7a,b) as well as their application in dye-sensitized solar cells (DSSCs). In the three designed dyes, the electron-donor exTTF group is connected to the rhodanine-3-acetic acid electron-acceptor unit through vinyl or vinyl-thiophene spacers. The electrochemical studies showed that the energy gap between the LUMO level of the dyes and the TiO₂ conduction band decreases with the length of the conjugated system. As a consequence, the power conversion efficiencies of organic DSSCs fabricated with these dyes scale inversely with their light-harvesting ability.