Heteroleptic ruthenium complexes containing uncommon 5,5′- disubstituted-2,2′-bipyridine chromophores for dye-sensitized solar cells

Feng Rong Dai, Wen Jun Wu, Qi Wei Wang, He Tian, Wai Yeung Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

24 Citations (Scopus)

Abstract

Four new heteroleptic ruthenium sensitizers [Ru(4,4′-carboxylic acid-2,2′-bipyridine)(L)(NCS)2] (L = 5,5′-bis(4- octylthiophen-2-yl)-2,2′-bipyridine (1), 5,5′-bis(N,N-diphenyl-4- aminophenyl)-2,2′-bipyridine (2), 5,5′-bis(5-(N,N-diphenyl-4- aminophenyl)-thiophen-2-yl)-2,2′-bipyridine (3) and 5,5′-bis(4- octyl-5-(N,N-diphenyl-4-aminophenyl)-thiophen-2-yl)-2,2′-bipyridine (4)) were synthesized, characterized by physicochemical and computational methods, and utilized as photosensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The λmaxof the metal-to-ligand charge transfer (MLCT) absorption of these four ruthenium dyes (527 nm for 1, 535 nm for 2, 585 nm for 3 and 553 nm for 4) can be tuned by various structural modifications of the ancillary ligand and it was shown that increasing the conjugation length of such ligand reduces the energy as well as the molar absorption coefficient of the MLCT band. The maximum incident photon to current conversion efficiency (IPCE) of 41.4% at 550 nm, 38.6% at 480 nm, 39.4% at 470 nm and 31.1% at 480 nm for 1-, 2-, 3- and 4-sensitized solar cells were obtained. Respectable power conversion efficiencies of 3.00%, 2.51%, 2.00% and 2.03% were realized, respectively, when the sensitizers 1, 2, 3 and 4 were used in DSSCs under the standard air mass (AM) 1.5 sunlight illumination (versus 5.9% for standard N719).
Original languageEnglish
Pages (from-to)2314-2323
Number of pages10
JournalDalton Transactions
Volume40
Issue number10
DOIs
Publication statusPublished - 14 Mar 2011
Externally publishedYes

ASJC Scopus subject areas

  • Inorganic Chemistry

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