In this study, three donor-p-acceptor (D-p-A) type unsymmetrical porphyrin-based dyes have been
designed and synthesized for dye-sensitized solar cells (DSSCs). The photophysical, electrochemical and
photovoltaic properties of the dyes were successfully adjusted by using functionalized arylamines (triphenylamine
or N, N-dimethyl-4-(acetylene)-aniline) as donor, porphyrin derivatives as conjugated p
bridge, ethynyl-thiophene or ethynyl-thiophthene as p spacer and carboxylic acid as anchor group.
Compared with the dye containing ethynyl-thiophene as p spacer, the dyes containing 2-ethynyl-6-
methylthieno[3,2-b]thiophene as p spacer between the porphyrin macrocycle and the carboxylic acid
anchoring group show broadened absorption spectra on TiO2 films and red-shifted absorption spectra in
solution. The dye based on triphenylamine and 2-ethynyl-6-methylthieno[3,2-b]thiophene exhibited a
power conversion efficiency (PCE) of 4.53% under simulated air mass 1.5 global sunlight. These results
indicate that the introduction of 2-ethynyl-6-methylthieno[3,2-b]thiophene in the meso-positions of
porphyrin dyes is an effective approach to improve the photovoltaic performance.