Synthesis and Characterization of A New pi-Conjugated Polymer with Cyanoacrylate Side Chain for Organic Thin Film Transistors

Abstract

A new copolymer, poly(carbazol-9-yl)phenyl)-2-cyanoacrylate)-alt-(2,2'-(1,5-bis(hexyloxy)naph thalene-2,6-diyl)dithiophene)) (PCCNT) with cyanoacrylate, was synthesized by the Stille coupling reaction for p-type semiconductors in OTFTs. FTIR and H-1 NMR spectroscopes confirmed the structure of PCCNT. The molecular weight of polymer was 14.6 kDa with polydispersity index of 1.72 using GPC. The obtained polymer with long alkyl side chains demonstrated good solubility. PCCNT has good thermal stability of (T-d=324) as well as good oxidation stability with a HOMO level of -5.35 eV. UV-Vis absorption maximum of the polymer was found at 431 nm in solution and at 444 nm for the film, respectively. In the photoluminescence (PL), the large red-shift was observed from solution emission (lambda(max) 493 nm) to film emission (lambda(max) 539 nm) due to an intermolecular interaction. The fabricated bottom gate-top contact organic thin film transistors (OTFTs) showed field-effect mobility of 9.02x10(-5) cm(2)/Vs and threshold voltage of -3 V.