Resonance Raman Study of New Pyrrole-Anchoring Dyes for NiO-Sensitized Solar Cells

Three dyes for p-type dye-sensitised solar cells containing a novel doubly anchored pyrroledonor group were synthesised and their solar cell performances were evaluated. Dye 1 wascomprised of a phenyl-thiophene linker and a maleonitrile acceptor, which has beenestablished as an effective motif in other push-pull dyes. Two boron dipyrromethaneanalogues, dyes 2 and 3, were made with different linker groups to compare their effect onthe behaviour of these dyes adsorbed onto nickel oxide (dye|NiO) under illumination. Thephoto-excited states of dye|NiO were probed using resonance Raman spectroscopy andcompared to dyes anchored using the conventional 4-aminobenzoic acid moiety (P1 and 4).All three components, the anchor, the linker and the acceptor group were found to alter bothJournal of Materials Chemistry C Page 2 of 332the electronic structure following excitation and the overall solar cell performance. Thebodipy acceptor gave a better performance than the maleonitrile acceptor when the pyrroleanchor was used, which is the opposite of the triphenylamine push-pull dyes. The linkergroup was found to have a large influence on the short-circuit current and efficiency of the ptypecells constructed.