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Efficient Organic Dye‐Sensitized Solar Cells: Molecular Engineering of Donor–Acceptor–Acceptor cationic dyes
Author(s) -
Cheng Ming,
Yang Xichuan,
Zhao Jianghua,
Chen Cheng,
Tan Qin,
Zhang Fuguo,
Sun Licheng
Publication year - 2013
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201300481
Subject(s) - photochemistry , dye sensitized solar cell , acceptor , pyridine , pyridinium , chemistry , electron acceptor , cationic polymerization , electrolyte , alkyl , thiophene , electron donor , materials science , polymer chemistry , organic chemistry , catalysis , electrode , physics , condensed matter physics
Three metal‐free donor–acceptor–acceptor sensitizers with ionized pyridine and a reference dye were synthesized, and a detailed investigation of the relationship between the dye structure and the photophysical and photoelectrochemical properties and the performance of dye‐sensitized solar cells (DSSCs) is described. The ionization of pyridine results in a red shift of the absorption spectrum in comparison to that of the reference dye. This is mainly attributable to the ionization of pyridine increasing the electron‐withdrawing ability of the total acceptor part. Incorporation of the strong electron‐withdrawing units of pyridinium and cyano acrylic acid gives rise to optimized energy levels, resulting in a large response range of wavelengths. When attached to TiO 2 film, the conduction band of TiO 2 is negatively shifted to a different extent depending on the dye. This is attributed to the electron recombination rate between the TiO 2 film and the electrolyte being efficiently suppressed by the introduction of long alkyl chains and thiophene units. DSSCs assembled using these dyes show efficiencies as high as 8.8 %.