Patent ID: 8765882

Claim:
A blend for use in a photovoltaic device, comprising: (a) a polymer, wherein the polymer is selected from the group consisting of a random co-polymer, an alternating co-polymer, and a block co-polymer, and wherein the polymer comprises at least one comonomer of formula (VII): wherein R is selected from the group consisting of a linear alkyl group having from 6 to 10 carbon atoms and a branched alkyl group having from 6 to 10 carbon atoms; and monomer units of formula (IV): wherein L is selected from the group consisting of a linear alkylene group having 5 carbon atoms and a branched alkylene group having 5 carbon atoms; and J is selected from the group consisting of a hydrogen atom, a linear alkyl group having from 1 to 4 carbon atoms, and a branched alkyl group having from 1 to 4 carbon atoms; and (b) an electron acceptor, wherein the electron acceptor is a fullerene derivative, wherein the fullerene derivative is [6,6]-phenyl-C 61 -butyric acid methyl ester, the blend having 10% of functionalized side chains and a thermally stable morphology.