'Surfaces-as-ligands, surfaces-as-complexes' strategies for copper(I) dye-sensitized solar cells. (April 2015)

• Record Type: Journal Article
• Authors: Schönhofer, Ewald; Bozic-Weber, Biljana; Martin, Colin J.; Constable, Edwin C.; Housecroft, Catherine E.; Zampese, Jennifer A.
• Is Part Of: Dyes and pigments. Volume 115(2015)
• Page Start: 154
• Page End: 165
• Publication Date: 2015-04
• Subjects: Copper -- Ruthenium -- Sensitizer -- DSSC -- Surface-functionalization -- Surface-as-ligand; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2014.12.022
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A series of TiO2 -supported copper(I) dyes, [Cu(Lanchor ) (Lancillary )] + with Lancillary = 2, 2′:4′, 4″:2″, 2‴-quaterpyridine (1 ), 4, 4′-bis(6-methyl-[2, 2′-bipyridin]-4-yl)-1, 1′-biphenyl (2 ), or 4, 4′-bis(6, 6′-dimethyl-[2, 2′-bipyridin]-4-yl)-1, 1′-biphenyl (3 ), and Lanchor = (6, 6′-dimethyl-[2, 2′-bipyridine]-4, 4′-diyl)bis(4, 1-phenylene)bis(phosphonic acid) (4 ), has been assembled in a stepwise manner. DSSCs incorporating these dyes demonstrate the need for 6, 6′-substituents in both ligands in [Cu(Lanchor ) (Lancillary )] + ; both J SC and V OC increase on going from [Cu(4 ) (1 )] + to [Cu(4 ) (2 )] + to [Cu(4 ) (3 )] + . First, second and third generation dyes [(4 ){Cu(3 )}n ] n+ (n = 1, 2 or 3) have been assembled using the 'surfaces-as-ligands, surfaces-as-complexes' strategy, although the separation between sites of electron injection and hole transporting domains in the multinuclear complexes fails to enhance DSSC performance. Replacing Lancillary 2 in [Cu(4 ) (2 )] + by the metalloligand {Ru(bpy)2 (2 )} 2+ improves dye performance due to the better spectral response of the heteronuclear [Cu(4 ){(2 )Ru(bpy)2 }] 3+ complex. This assembly approach presents a flexible method of tuning dye properties while retaining the surface-bound bis(diimine)copper(I) domain. Graphical abstract: First, second and third generation TiO2 -anchored copper(I) dyes [(Lanchor ){Cu(Lancillary )}n ] n+ (n = 1, 2 or 3) in which Lancillary is a ditopic bis(2, 2′-bipyridine) domain and Lanchor contains 2, 2′-bipyridine and phosphonic acid domains have been assembled using a versatile 'surfaces-as-ligands, surfaces-as-complexes' strategy. We demonstrate that 6, 6′-substituents are required in both ligands in first-generation [Cu(Lanchor ) (Lancillary )] + to enhance J SC and V OC values. Replacing Lancillary by a metalloligand {Ru(bpy)2 (Lancillary )} 2+ improves dye performance due to the better spectral response of the heterometallic [(Lanchor )Cu{(Lancillary )Ru(bpy)2 }] 3+ complex. Highlights: Stepwise assembly of anchored dyes in n-type DSSCs. 'Surfaces-as-ligands, surfaces-as-complexes' dye assembly. Atom efficient dye assembly strategies to construct homometallic or heterometallic dyes. On-surface strategies for dye assembly on n-type semiconductor surfaces.