Patent ID: 7772485

Claim:
A photovoltaic cell, comprising: a first electrode, a second electrode, and a photoactive material disposed between the first and second electrodes, the photoactive material comprising a polymer including a first comonomer repeat unit and a second comonomer repeat unit, the first comonomer repeat unit comprising a cyclopentadithiophene moiety of formula (I): and the second comonomer repeat unit comprising a benzothiadiazole moiety of formula (II): wherein each of R 1 and R 2 in formula (I), independently, is H, C 1 -C 20 alkyl, C 1 -C 20 alkoxy, aryl, heteroaryl, C 3 -C 20 cycloalkyl, or C 3 -C 20 heterocycloalkyl; and each of R 1 and R 2 in formula (II), independently, is H, C 1 -C 20 alkyl, C 1 -C 20 alkoxy, aryl, heteroaryl, C 3 -C 20 cycloalkyl, or C 3 -C 20 heterocycloalkyl.