Interfacial Charge Transfer in Dye-Sensitized Solar Cells Using SCN-Free Terpyridine-Coordinated Ru Complex Dye and Co Complex Redox Couples.
The efficiency of dye-sensitized solar cells (DSSCs) using Ru complex dyes and Co complex redox couples has been increased with a strategy to prevent charge recombination via the addition of bulky or lengthy peripheral units to the dyes. However, despite the efforts, most of the DSSCs are still suffering from nonunity quantum efficiency and fast recombination. We examine the effect of SCN ligand, which has been used for many Ru complex dyes and could attract positively charged Co complexes. We find that replacing the ligands with 2,6-bis(2'-(4'-trifluoromethyl)pyrazolyl)pyridine increases the quantum efficiency and electron lifetime. With the combination of the replacement of SCN ligands and the addition of bulky moiety, ∼80% external quantum efficiency is achieved. These suggest that not only the addition of a blocking effect but also the reduction of electrostatic and dispersion forces between dyes and Co complexes are essential to control the charge separation and recombination processes.
Center for Energy and Environmental Science, Shinshu University , 4-17-1 Wakasato, Nagano 380-8553, Japan.
Takahiro
T
Kono
Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, 386-8567 Japan.
Naruhiko
N
Masaki
Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, 386-8567 Japan.
Masahiro
M
Nishikawa
Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, 386-8567 Japan.
Rei
R
Tamura
National Institute of Advanced Industrial Science and Technology Central 2 , Umezono 1-1-1, Tsukuba, Ibaraki 305-8568, Japan.
Hiroyuki
H
Matsuzaki
Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, 386-8567 Japan.
Mutsumi
M
Kimura
Center for Energy and Environmental Science, Shinshu University , 4-17-1 Wakasato, Nagano 380-8553, Japan.|Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, 386-8567 Japan.
Shogo
S
Mori
blocking effect; charge recombination; charge separation efficiency; dispersion force; intermolecular force