Self‐Doping Naphthalene Diimide Conjugated Polymers for Flexible Unipolar n‐Type OTFTs

Abstract The development of high‐performance organic thin‐film transistor (OTFT) materials is vital for flexible electronics. Numerous OTFTs are so far reported but obtaining high‐performance and reliable OTFTs simultaneously for flexible electronics is still challenging. Herein, it is reported that 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 are designed and synthesized. The effects of self‐doping on the electronic properties of resulting flexible OTFTs are investigated. The results reveal that the flexible OTFTs based on self‐doped PNDI2T‐NM17 exhibit 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 are fourfold 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.