Enhancement of organic field-effect transistor performance by incorporating functionalized double-walled carbon nanotubes

Abstract

Excellent electrical properties and large-scale fabrication are essential for extending the application of flexible organic electronics in practice. Organic semiconductor materials usually suffer from low charge carrier mobility, while carbon-based materials, such as graphene and carbon nanotubes (CNTs), often exhibit a rather low on/off ratio. Incorporating carbon-based materials into organic field-effect transistors (OFETs) is expected to combine their advantages. However, the dispersity of CNTs in organic semiconductors is rather poor, leading to a limited development of the hybrid devices. In this work, we overcame the challenge by subtly utilizing the advantages of covalently functionalized double-walled carbon nanotubes (f-DWCNTs). The f-DWCNTs can be well dispersed in solutions of organic semiconductor with a wide concentration range, which also makes the hybrid devices solution processable. OFETs based on f-DWCNT and an organic semiconductor hybrid exhibited higher source-drain currents as compared with that based on an organic semiconductor only. In addition, the threshold voltage of the OFETs decreased obviously due to charge injection enhancement by the f-DWCNTs. The comprehensive electric performance of the hybrid OFETs were further optimized by adjusting the mixing ratio of the two materials. Therefore, we demonstrated that incorporating f-DWCNTs into organic semiconductors is a simple and effective route to enhance the electric performance of solution-processed OFETs, and this strategy is expected to further advance flexible organic electronics for practical applications.