Compared to PffBT4T-2OD (PCE11), PffBT4T-C9C13 has larger side chains which help promote better solubility and film morphology. When using?PffBT4T-C9C13 as a polymer donor and PC71BM as electron acceptor (with trimethylbenzene (TMB) as host solvent), a?higher device performance of 11.7% was achieved [2].