title: Synthesis, structure, and properties of [Pt(II)(diimine)(dithiolate)] dyes with 3,3'-, 4,4'-, and 5,5'-disubstituted bipyridyl: applications in dye-sensitized solar cells.
abstract: A family of [Pt(II)(diimine)(dithiolate)] complexes of general formula [Pt{X,X'(CO(2)R)(2)-2,2'-bipyridyl}(maleonitriledithiolate)] (where X = 3, 4, or 5 and R = H or Et) have been synthesized, spectroscopically and electrochemically characterized, and attached to a TiO(2) substrate to be tested as solar cell sensitizers. A single-crystal X-ray structure showing a large torsion angle between the bipyridyl rings was determined for [Pt{3,3'(CO(2)Et)(2)-2,2'-bipyridyl}(maleonitriledithiolate)].MeCN. The effect of changing the position of the bipyridyl substituents from 3,3' to 4,4' and 5,5' is discussed with reference to structural and electronic changes seen within the different members of the family of molecules. The first UV/vis/NIR spectroelectrochemical study of complexes of this general formula is discussed. All three complexes (where R = H) were tested as solar cell sensitizers, with the 3,3'-disubstituted bipyridyl complex giving an intermediate dye loading value but superior photovoltaic performance to those of the other two. The performance of this sensitizer is then compared with that of a well-known Ru polypyridyl sensitizer, the ditetrabutylammonium salt of [RuL(2)(NCS)(2)] (L = 2,2'-bipyridyl-4,4'-dicarboxylato), commonly called N719.
authors.affiliation: School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, UK.
authors.forename: Elaine A M
authors.initials: EA
authors.lastname: Geary
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Yellowlees
authors.forename: Lorna A
authors.initials: LA
authors.lastname: Jack
authors.forename: Iain D H
authors.initials: ID
authors.lastname: Oswald
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Narukuni
authors.initials: N
authors.lastname: Hirata
authors.forename: James R
authors.initials: JR
authors.lastname: Durrant
authors.forename: Neil
authors.initials: N
authors.lastname: Robertson