TY - JOUR AB - A new synthetic route, to prepare an alkylated indacenodithieno[3,2-b]thiophene-based nonfullerene acceptor (C8-ITIC), is reported. Compared to the reported ITIC with phenylalkyl side chains, the new acceptor C8-ITIC exhibits a reduction in the optical band gap, higher absorptivity, and an increased propensity to crystallize. Accordingly, blends with the donor polymer PBDB-T exhibit a power conversion efficiency (PCE) up to 12.4%. Further improvements in efficiency are found upon backbone fluorination of the donor polymer to afford the novel material PFBDB-T. The resulting blend with C8-ITIC shows an impressive PCE up to 13.2% as a result of the higher open-circuit voltage. Electroluminescence studies demonstrate that backbone fluorination reduces the energy loss of the blends, with PFBDB-T/C8-ITIC-based cells exhibiting a small energy loss of 0.6 eV combined with a high JSCof 19.6 mA cm-2. AU - Fei,Z AU - Eisner,FD AU - Jiao,X AU - Azzouzi,M AU - Röhr,JA AU - Han,Y AU - Shahid,M AU - Chesman,ASR AU - Easton,CD AU - McNeill,CR AU - Anthopoulos,TD AU - Nelson,J AU - Heeney,M AU - Heeney,MJ AU - Fei,Z AU - Jiao,X AU - Eisner,F AU - Azzouzi,M AU - Rohr,J AU - Han,Y AU - Shahid,M AU - Chesman,A AU - Easton,C AU - McNeill,C AU - Nelson,J AU - Anthopoulos,T DO - 10.1002/adma.201705209 EP - 7 PY - 2018/// SN - 0935-9648 SP - 1 TI - An alkylated indacenodithieno[3,2-b]thiophene-based nonfullerene acceptor with high crystallinity exhibiting single junction solar cell efficiencies greater than 13% with low voltage losses T2 - Advanced Materials UR - http://dx.doi.org/10.1002/adma.201705209 UR - https://www.ncbi.nlm.nih.gov/pubmed/29315933 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201705209 UR - http://hdl.handle.net/10044/1/57318 VL - 30 ER -