Dramatic Inversion of Charge Polarity in Diketopyrrolopyrrole‐Based Organic Field‐Effect Transistors via a Simple Nitrile Group Substitution

A record-breaking high electron mobility of 7.0 cm(2) V(-1) s(-1) for n-channel polymer OFETs is reported. By the incorporation of only one nitrile group as an electron-withdrawing function in the vinyl linkage of the DPP-based copolymer, a dramatic inversion of majority charge-carriers from holes to electrons is achieved.