Effect of the Fibrillar Microstructure on the Efficiency of High Molecular Weight Diketopyrrolopyrrole‐Based Polymer Solar Cells

Abstract

The nature of the solubilizing alkyl side chains has a strong effect on the performance of semiconducting diketopyrrolopyrrole polymers in organic solar cells with fullerene acceptors. The effect relates to the width of semicrystalline polymer fibrils that form in these blends. If the width of the fibril is wider than the exciton diffusion length, fewer charges form and the efficiency drops.