A Postalignment Method for High-Mobility Organic Thin-Film Transistors

Abstract

Efficient charge carrier transport in organic thin film transistors (OTFTs) often requires thin films with highly oriented feature. Although there are a number of methods to effectively form high-degree and large-scale alignment during the process of film formation, these methods usually resulted in nonuniform films. In order to obtain highly aligned uniform films, this paper provides a postalignment method after film formation. By applying electric field during solvent annealing, the polymer backbone can be reorganized along the direction of the electric field, leading to highly aligned polymer chains and significant improvement in charge mobility. In addition, after doping the polymer films with liquid crystal (LC), with the benefit of LC molecules' template, the degree of orientation of polymer molecular chains was further enhanced, resulting in further improvement of the charge mobility up to 9.42 cm2·V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ·s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . This paper exhibits the possibility of improving charge transport after film formation to obtain high-performance solution-processable OTFT for low-cost and large-scale organic electronics.