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

摘要

A series of TiO2-supported copper(I) dyes, [CL(L-anchor) (L-ancillary)](+) with L-ancillary = 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-y1)-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(L-anchor) (L-ancillary)]+; 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 Lancfflary 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. (C) 2015 Elsevier Ltd. All rights reserved.