Diastereoisomers of Ruthenium Dyes with Unsymmetric
Ligands for DSC: Fundamental Chemistry and Photovoltaic Performance
- Publication date
- Publisher
Abstract
A new
thiocyanic acid-free ruthenium sensitizer, CYC-B29, containing
two unsymmetrical ancillary ligands, was synthesized, and its three
diastereoisomers CYC-B29-CC, CYC-B29-TT, and CYC-B29-CT with significantly
different optical, electronic, and electrochemical properties were
carefully separated. CYC-B29-TT with the smallest size has the strongest
absorption coefficient of the MLCT band, the shortest 位<sub>max</sub>, the lowest highest occupied molecular orbital level and
the highest dye loading. Therefore, dye-sensitized solar cell based
on CYC-B29-TT has the highest efficiency, which is two times higher
than that of CYC-B29-CC-sensitized device and 10% higher than that
of N719-based cell. Time-dependent density functional theory-calculated
transition bands for the three isomers are not identical, and only
CYC-B29-TT has the calculated transition bands close to the experimental
absorption profile. Although the calculated transition
bands for CYC-B29-CC and CYC-B29-CT are not consistent with the experimental
data, the ground-state vertical excitation energy with oscillator
strength and electron-density difference map data combining with the
dye loading predict correctly the order of the photocurrent for the
three isomers sensitized devices