title: Nature of Excited States of Ruthenium-Based Solar Cell Dyes in Solution: A Comprehensive Spectroscopic Study.
abstract: The photophysical properties of a number of ruthenium complexes of the general structure [Ru(L1)(L2)(NCS)2], related to the prominent solar cell dye [Ru(dcb)2(NCS)2] (dcb = 4,4'-dicarboxylato-2,2'-bipyridine) are investigated. For L1 = dcb and dmb (dmb = 4,4'-dimethyl-2,2'-bipyridine), several variations of L2 show very little difference in the lowest energy absorption peak. Resonance Raman and density functional theory calculations have been used to assign the corresponding transitions as {Ru(NCS)2} → dcb with significant contributions of the NCS ligands. Transient absorption, time-resolved infrared, and transient resonance Raman spectroscopic techniques were used to probe the photophysics of the complexes and relatively short-lived {Ru(NCS)2} → dcb/dpb (dpb = 4,4'-diphenylethenyl-2,2'-bipyridine) excited states were observed with the exception of [Ru(dcb)(dab)(NCS)2] (dab = 4,4'-dianthracenethenyl-2,2'-bipyridine), which showed a long-lived excited state assigned as ligand centered charge separated.
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Raphael
authors.initials: R
authors.lastname: Horvath
authors.affiliation: Department of Chemistry, University of Otago , Dunedin 9001, New Zealand.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fraser
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Clark
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Sun
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.|Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China , 199 Talking East Road, Ningbo 315100, China.
authors.forename: Michael W
authors.initials: MW
authors.lastname: George
authors.affiliation: Department of Chemistry, University of Otago , Dunedin 9001, New Zealand.
authors.forename: Keith C
authors.initials: KC
authors.lastname: Gordon