title: Phenomenally high molar extinction coefficient sensitizer with "donor-acceptor" ligands for dye-sensitized solar cell applications.
abstract: A phenomenally high molar extinction coefficient heteroleptic ruthenium(II) complex [Ru(4,4'-carboxylic acid-2,2'-bipyridine)(4,4'-(4-{4-methyl-2,5-bis[3-methylbutoxy]styryl}-2,5-bis[3-methylbutoxy]-2,2'-bipyridine)(NCS) 2] ( DCSC13) was synthesized by incorporating donor-acceptor ligands. The absorption spectrum of the DCSC13 sensitizer is dominated by metal-to-ligand charge-transfer transitions (MLCT) in the visible region, with absorption maxima appearing at 442 and 554 nm. The lowest MLCT absorption bands are red-shifted, and the molar extinction coefficients of these bands are significantly higher at 72,100 and 30,600 M(-1) cm(-1), respectively, when compared to those of the analogous [Ru(4,4'-carboxylic acid-2,2'-bipyridine)(4,4'-dimethyl-2,2'-bipyridine)(NCS)2] (N820) sensitizer. The DCSC13 complex, when anchored on nanocrystalline TiO 2 films, exhibited increased short-circuit photocurrent and consequent power-conversion efficiency when compared with the N820 sensitizer.
authors.affiliation: Department of Chemistry, Korea University, Jochiwon, Chungnam 339-700, Korea.
authors.forename: Chongchan
authors.initials: C
authors.lastname: Lee
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Yum
authors.forename: Hyunbong
authors.initials: H
authors.lastname: Choi
authors.forename: Sang
authors.initials: S
authors.lastname: Ook Kang
authors.forename: Jaejung
authors.initials: J
authors.lastname: Ko
authors.forename: Robin
authors.initials: R
authors.lastname: Humphry-Baker
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Md K
authors.initials: MK
authors.lastname: Nazeeruddin