Converting a Semiconducting Polymer from Ambipolar into n‐Type Dominant by Amine End‐Capping

Abstract A donor‐acceptor polymer of (3 E ,7 E )‐3,7‐bis(2‐oxoindolin‐3‐ylidene)benzo[1,2‐ b : 4,5‐ b ′]difuran‐2,6(3 H ,7 H )‐dione (IBDF) and bithiophene (BT) exhibits typical ambipolar charge transport behaviour in organic thin film transistors. Using the electron rich triphenylamine as an end capping group, a notable suppression of hole transport is observed. This interesting phenomenon is accounted for by the hole trapping effect of the triphenylamine end‐capper. Thus, this study provides a novel and facile approach to tuning the charge carrier polarity of a polymer semiconductor from ambipolar to n‐type dominant.