Self-doping Naphthalene Diimide Conjugated Polymers for Flexible Unipolar n-type OTFTs.

The development of high-performance organic thin-film transistor (OTFT) materials is vital for flexible electronics. Numerous OTFTs have so far been reported but obtaining high-performance and reliable OTFTs simultaneously for flexible electronics is still challenging. Herein, we report self-doping in conjugated polymer enables high unipolar n-type charge mobility in flexible OTFTs, as well as good operational/ambient stability and bending resistance. New naphthalene diimide (NDI) conjugated polymers PNDI2T-NM17 and PNDI2T-NM50 with different contents of self-doping groups on their side chains were designed and synthesized. The effects of self-doping on the electronic properties of resulting flexible OTFTs were investigated. The results revealed the flexible OTFTs based on self-doped PNDI2T-NM17 exhibited unipolar n-type charge-carrier properties and good operational/ambient stability thanks to the appropriate doping level and intermolecular interactions. The charge mobility and on/off ratio were four-fold and four-orders of magnitude higher than those of undoped model polymer, respectively. Overall, the proposed self-doping strategy is useful for rationally designing OTFT materials with high semiconducting performance and reliability. This article is protected by copyright. All rights reserved.