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Heteroleptic copper(I) sensitizers with one versus two hole-transporting units in functionalized 2,9-dimethyl-1,10-phenanthroline ancillary ligands

Fürer, S. O. and Bozic-Weber, B. and Neuburger, M. and Constable, E. C. and Housecroft, C. E.. (2015) Heteroleptic copper(I) sensitizers with one versus two hole-transporting units in functionalized 2,9-dimethyl-1,10-phenanthroline ancillary ligands. RSC advances, 5 . pp. 69430-69440.

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Official URL: http://edoc.unibas.ch/dok/A6419807

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Abstract

A series of homoleptic [Cu(L)2][PF6] complexes in which L is a 2,9-dimethyl-1,10-phenanthroline fused at the 5,6-positions with a 2′-functionalized imidazole (ligands 1–4), or substituted at the 4,7-positions with electron-donating 4-(diphenylamino)phenyl groups (ligand 5) is described; the imidazole 2′-functionality in 1 is 4-bromophenyl, in 2 is 4-(diphenylamino)phenyl, in 3 is 4-(bis(4-n-butoxy)phenylamino)phenyl, and in 4 is 4-(carbazol-9-yl)phenyl. The copper complexes were characterized by mass spectrometry, NMR and absorption spectroscopies and cyclic voltammetry; the single crystal structure of ligand 4 has been determined. Compared to the solution absorption spectra of [Cu(1)2][PF6], [Cu(2)2][PF6], [Cu(3)2][PF6] and [Cu(4)2][PF6], that of [Cu(5)2][PF6] shows increased absorbance at wavelengths >375 nm. An on-surface strategy was used to assemble heteroleptic [Cu(6)(L)]+ dyes on TiO2 electrodes where 6 is ((6,6′-dimethyl-[2,2′-bipyridine]-4,4′-diyl)bis(4,1-phenylene))bis(phosphonic acid); solid-state absorption spectra confirmed enhanced light-harvesting between 375 and 600 nm for [Cu(6)(5)]+ with respect to [Cu(6)(1)]+, [Cu(6)(2)]+, [Cu(6)(3)]+ and [Cu(6)(4)]+. Comparison of the performances of dye-sensitized solar cells (DSCs) containing [Cu(6)(2)]+, [Cu(6)(3)]+ and [Cu(6)(4)]+ with those with [Cu(6)(1)]+ indicate only a marginal influence of the diphenylamine or carbazole hole-transporting domains in 5,6-substituted phenanthroline dyes. The introduction of the 4-(diphenylamino)phenyl hole-transporting units in the 4- and 7-positions of the phen unit in 5 proves to be beneficial, with DSCs containing [Cu(6)(5)]+ performing better than those with the other four dyes; duplicate DSCs were tested for each dye to validate the results. While the values of the maximum external quantum efficiencies (EQEmax) for [Cu(6)(1)]+ and [Cu(6)(4)]+ are greater than for [Cu(6)(5)]+, the extension of the EQE spectrum for [Cu(6)(5)]+ to longer wavelengths results in higher short-circuit current densities (JSC) compared to DSCs with [Cu(6)(1)]+, [Cu(6)(2)]+, [Cu(6)(3)]+ and [Cu(6)(4)]+.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Anorganische Chemie (Constable)
05 Faculty of Science > Departement Chemie > Chemie > Anorganische Chemie (Housecroft)
UniBasel Contributors:Housecroft, Catherine Elizabeth and Constable, Edwin Charles and Fürer, Sebastian and Neuburger, Markus and Bozic Weber, Biljana
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:Royal Society of Chemistry
ISSN:2046-2069
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:31 Dec 2015 10:58
Deposited On:02 Oct 2015 10:00

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