Patent ID: 8450604

Claim:
A solar cell comprising: a substrate; and a stable active layer atop the substrate, the stable active layer comprising a crosslinked conjugated polymer material, obtained by irradiating a blend in an absence of a photoinitiator, said blend comprising: a conjugated polymer, and an n-type or p-type compound, said conjugated polymer containing one or more repeating units represented by the structural formula: wherein: Ar is a homocyclic or heterocyclic aromatic group selected from the group consisting of thienyl, phenyl, naphthyl, pyrrolyl, pyridyl, carbazolyl, fluorenyl and benzothiazolyl; L is selected from the group consisting of —O—, —CH(CH 3 )—O—, —(CH 2 ) q —O—, —NH—, —CH(CH 3 )—NH—, —(CH 2 ) q —NH—, —S—, —CH(CH 3 )—S— and —(CH 2 ) q —S—, wherein the oxygen atom of said —CH(CH 3 )—O— or —(CH 2 ) q —O— is adjacent to the carbonyl group of the repeating unit, wherein the NH group of said —CH(CH 3 )—NH— or —(CH 2 ) q —NH— is adjacent to the carbonyl group of the repeating unit and, wherein the sulphur atom of said —CH(CH 3 )—S— or —(CH 2 ) q —S— is adjacent to the carbonyl group of the repeating unit; q is 1, 2 or 3; R 1 and R 2 are independently selected from the group consisting of hydrogen, C 1-4 alkyl and phenyl, wherein said phenyl is unsubstituted or substituted with one or more substituents independently selected from the group consisting of halogen and methoxy; R 3 is selected from the group consisting of hydrogen, C 1-4 -alkyl and phenyl; and R 4 is hydrogen or methyl.