Ladder-type oligo-p-phenylene-containing copolymers with high open-circuit voltages and ambient photovoltaic activity

Abstract

Ladder-type oligo-p-phenylene containing donor-acceptor copolymers are disclosed. The ladder-type oligo-p-phenylene can be used as an electron donor unit in the disclosed copolymers to provide a deeper highest occupied molecular orbital (HOMO) level for obtaining polymeric solar cells having a higher open-circuit voltage. Particular electron-accepting units, e.g., a divalent fused-ring heterocyclic moiety selected from the group consisting of a substituted or unsubstituted benzothiadiazole, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted benzobisthiazole, and a substituted or unsubstituted naphthothiadiazole, can be used to tune the electronic band gaps of the polymers for a better light harvesting ability. The disclosed copolymers exhibit field-effect mobilities as high as 0.011 cm2/(V s). Compared to fluorene-containing copolymers with the same acceptor unit, the disclosed ladder-type oligo-p-phenylene containing copolymers have enhanced and bathochromically shifted absorption bands and much better solubility in organic solvents.

Dependencies are inferred from the claim text.