Fluorenone imide/cyanated fluorenone imide and diketopyrrolopyrrole-based dual-acceptor polymers for n-type organic thin-film transistors†

It is of great significance to develop high performance n-type polymer semiconductors (PSCs), which are essential for fabricating various p–n junction organic electronic devices. In this work, based on commonly used acceptor unit diketopyrrolopyrrole (DPP) and recently developed acceptors fluorenone imide (FOI)/cyanated fluorenone imide (FCNI), we prepared two new dual-acceptor (A1–A2) type PSCs, PFOI-DPP and PFCNI-DPP. Benefitting from improved components of the acceptor moieties in their backbones, the two polymers exhibited low-lying frontier molecular orbital energy levels. Theoretical simulation revealed that they also have a highly planar backbone. Ultimately, organic thin-film transistors based on the two polymers showed unipolar n-type characteristics with a maximum electron mobility of 0.55 cm² V⁻¹ s⁻¹.