Effect of source-drain electric field on charge transport mechanism in polymer-based thin-film transistors

Abstract

Provided are a polymer thin-film transistor and a method of fabricating the same. Donor-acceptor copolymer-based field-effect transistors (FETs) have attracted considerable attention from technological and academic perspectives due to their low band gap, high mobility, low cost, easy solution processability, flexibility, and stretchability. Large-area films can be formed through meniscus-guided coating among various solution-processing techniques. 29-Diketopyrrolopyrrole-selenophene vinylene selenophene (29-DPP-SVS) donor-acceptor copolymer-based FETs have already shown excellent performance due to their short π-π stacking distance and strong π-π interaction. Charge carrier mobility of these types of semiconductor materials significantly depends on an applied electric field. Accordingly, detailed analysis of the electric-field dependency of charge carrier mobility is necessary to understand the transport mechanism within the material. Therefore, 29-DPP-S VS-based FETs are fabricated by varying the blade coating (BC) speed of a semiconductor layer. The effect of the BC speed on the electrical characteristics of the FETs is studied through the analysis of electric-field-dependent mobility. The results show that the charge carrier mobility of different FETs depends on the applied electric field and that the type of dependency is Poole-Frenkel. At an optimized BC speed (2 mm s−1), the device shows maximum zero-field mobility (3.39 cm2V−1s−1) due to the low trap density within the conductive channel.

Dependencies are inferred from the claim text.