Facile Synthesis of Triphenylamine Based Hyperbranched Polymer for Organic Field Effect Transistors

In this study, we reported the synthesis and characterization of a novel hyperbranched polymer (HBPs) tris[(4-phenyl)amino-alt-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b’]dithiophene] (PTPABDT) composed of benzo[1,2-b:4,5-b’]dithiophene (BDT) and triphenyleamine (TPA) constituent subunits by A(3) + B(2) type Stille’s reaction. An estimated optical band gap of 1.69 eV with HOMO and LUMO levels of −5.29 eV and −3.60 eV, respectively, as well as a high thermal stability up to 398 °C were characterized for the synthesized polymer. PTPABDT fabricated as an encapsulated top gate/bottom contact (TGBC), organic field effect transistors (OFET) exhibited a p-type behavior with maximum field-effect mobility (µmax) and an on/off ratio of 1.22 × 10(−3) cm(2) V(−1) s(−1) and 7.47 × 10(2), respectively.