PTB7–Th/FPDI–CDTph-2F filmsexhibited continuous interpenetrating networks, which indicated well-defined nanoscale phase separation between donorand acceptor, thus more balanced carrier mobility and higherFF. This indicated that fluorination reduced excessive aggregation and phase separation which are harmful to charge separation and transport. In addition to the molecular modificationof acceptors, modification of donor structure would also inducedesirable morphology.