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

Abstract

In this study, we reported the synthesis and characterization of a novel hyperbranched polymer (HBPs) <i>tris</i>[(4-phenyl)amino-<i>alt</i>-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 A₃ + B₂ 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 cm² V^-1 s^-1 and 7.47 × 10², respectively.