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A Comparative Study on Two Ru II Complexes with Thiophene‐Based Ancillary Ligands for High‐Efficiency Dye‐Sensitized Solar Cells
Author(s) -
Su Rui,
Elmorsy Mohamed R.,
Abed Mira,
Islam Ashraful,
Lord Meghan,
Fadda Ahmed A.,
ElShafei Ahmed
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700468
Subject(s) - chemistry , dye sensitized solar cell , molar absorptivity , energy conversion efficiency , photovoltaic system , photocurrent , rhodanine , open circuit voltage , ligand (biochemistry) , thiophene , ruthenium , absorption (acoustics) , photochemistry , optoelectronics , electrolyte , organic chemistry , voltage , optics , materials science , electrode , catalysis , ecology , biochemistry , physics , receptor , quantum mechanics , biology
Heteroleptic polypyridyl Ru complexes MMR‐1 and MMR‐2 containing 2‐(methylthio)thienyl and 2‐(4‐methoxyphenyl)thienyl units on the antennas of ancillary ligands, respectively, were designed, synthesized, and characterized as sensitizers for dye‐sensitized solar cells. The maximum absorption wavelength of MMR‐1 is more red‐shifted than that of MMR‐2 , but MMR‐2 has a higher molar extinction coefficient, leading to better light harvesting. Under the same device‐fabrication conditions, the photovoltaic performances of these sensitizers were evaluated while anchored on mesoporous TiO 2 and compared to that of the benchmark N719 . Both MMR‐1 and MMR‐2 exhibited comparable or even higher solar‐to‐electric conversion efficiencies η with respect to N719 when employed as photosensitizers in DSSCs. Compared to MMR‐1 , MMR‐2 exhibited better overall conversion efficiency, which was attributed to the electron‐donating effect of the 4‐methoxyphenyl group and the better absorptivity by harvesting higher‐energy photons. Complex MMR‐2 also showed higher open‐circuit voltage V OC than MMR‐1 , which is likely due to the extension of the antenna of the ancillary ligand by inserting a phenyl group, which leads to less dye aggregation. The photovoltaic performance of MMR‐2 was better, with a short‐circuit photocurrent density of 16.76 mA cm –2 , a V OC of 0.673 V, a fill factor of 73.5 %, and an η value of 8.29 % with the addition of 0.5 m 4‐ tert ‐butylpyridine (TBP) compared to 8.18 % for N719 .