Light-harvesting fullerenes for organic solar cells

Novel dyads containing [60]fullerene-perylenediimide units were developed as light-harvesting acceptors for the preparation of efficient solar cells. The antenna was grafted onto C-60 with the aim to improve the absorption spectrum of materials used in bulk-heterojunction devices. Electrochemical and photophysical studies of these dyads in solution have revealed that there was no significant ground-state electronic interaction between the covalently bonded PDI and fullerene moieties. Steady-state fluorescence experiments evidenced an effective photoinduced energy transfer from the PDI moiety to C-60. The potential use of these light-harvesting fullerenes in organic solar cells was estimated with their incorporation in bulk-heterojunctions using poly(3-hexylthiophene) as the conjugated pi-donor polymer.