Fabrication of High Mobility n-type Conjugated Polymer Transistors using Kinetically Controlled Crystallization Method

Abstract

Organic field effect transistors (OFETs) have attracted much interest for future electronics because they can have flexibility with processing form solution at low temperature. Recently many researches make an attempt to control the film morphology which directly correlated to the charge transporting properties of conjugated polymers. In this work, we demonstrate a method to optimize poly {[N,N’-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6,-diyl]-alt-5,5’-(2,2’-bithiophene)} (P(NDI2OD-T2)) film morphologies by precisely regulating the solidification rate in the metastable state. The proposed simple method, Kinetically Controlled Crystallization (KCC) method, brings about dramatic morphological changes in both polymer domain sizes and molecular packing structures. The optimized P(NDI2OD-T2) films provide significantly increased electron mobilities up to 3.99 cm2 V-1s-1, which is almost two orders enhancement in performance compared with conventional spin-coated devices. The observation of low activation energy (62.51 meV) in optimized thin films can support the achievement of high electron mobilities of semiconducting polymers.