An Oligothiophene-Fullerene Molecule with a Balanced Donor-Acceptor Backbone for High-Performance Single-Component Organic Solar Cells

A new balanced donor-acceptor molecule, namely, benzodithiophene (BDT)-rhodanine-[6,6]-phenyl-C-71 butyric acid methyl ester (Rh-PC71BM) comprising two covalently linked blocks, a p-type oligothiophene-containing BDT-based moiety and an n-type PC71BM unit was designed and synthesized. The single-component organic solar cell (SCOSC) fabricated from Rh-PC71BM molecules showed a power conversion efficiency (PCE) of 3.22 % with an open-circuit voltage (V-oc) of 0.98 V. These results rank are among the highest values for SCOSCs based on a monomolecular material. In particular, the one-molecule Rh-PC71BM device exhibits excellent thermal stability compared to reference Rh-OH:PC71BM device. The success of our monomolecular strategy can provide a new way to develop high-performance SCOSCs.