Poly(o-toluidine) Nanowires Based Organic Field Effect Transistors: A Study on Influence of Anionic Size of Dopants and SWNTs as a Dopant

Abstract

Poly(o-toluidine) [P(OT)] nanowires electrode junction based organic field effect transistors (OFETs) with back-gated architecture are demonstrated. P(OT) nanowires have been site specifically synthesized to bridge Au micropatterns on Si/SiO2 substrate by facile galvanostatic route. Dopants with various sizes of anions have been employed during electrochemical synthesis of nanowires to study the possible impact of the same on electrochemical, morphological, spectroscopic, electrical, and FET characteristics. Observations show that varying the size of dopants significantly modulates crucial characteristic features of the FETs especially charge carrier mobility (mu) and on-off ratio (I-on/I-off). A probable model of the observed behavior suggests the anionic size of the dopants to be a dominant factor in deciding the conduction behavior of the FETs, and such rationalization is supported by spectroscopic and electrical data obtained. The device fabricated with carboxylated SWNTs as dopant exhibited superior FET properties than its counterparts in terms of mu = 3.17 X 10(-4) cm(2) V-1 s(-1) and I-on/I-off = 1.85 X 10(4).