Embedding electron-deficient nitrogen atoms in polymer backbone towards high performance n-type polymer field-effect transistors

With sp(2)-nitrogen atoms embedded in an isatin unit, a donor-acceptor (D-A) conjugated polymer AzaBDOPV-2T was developed with a low LUMO level down to -4.37 eV. The lowered LUMO level as well as the conformation-locked planar backbone provide AzaBDOPV-2T with electron mobilities over 3.22 cm(2) V(-1)s(-1) tested under ambient conditions, which is among the highest in n-type polymer field-effect transistors (FETs). Our results demonstrate that embedding electron-deficient sp(2)-nitrogen in conjugated backbones is an effective approach to develop n-type polymer semiconductors with high performance.