Abstract
Polymer acceptors are a class of "non-fullerene" electron-transporting materials that can replace [6,6]-phenyl C61/71 butyric acid (PC61/71BM) in bulk-heterojunction (BHJ) solar cells. In this contribution is reported the use of N-acyl-substituted isoindigo (IID) motifs (IID(CO)) as electron-deficient units in the design of polymer acceptors for "all-polymer" BHJ solar cells. While IID motifs are commonly used in the design of polymer donors for efficient BHJ solar cells with the fullerene PC61/71BM acceptors, here it is shown that IID(CO) building units used in conjunction with suitable co-monomers represent a practical avenue for polymer acceptors with electron affinity values comparable to that of PC61/71BM (i.e., 4.2 eV).