Semiconducting Polymers Based on Simple Electron-Deficient Cyanated trans-1, 3-Butadienes for Organic Field-Effect Transistors.

Abstract

Developing high-performance but low-cost n-type polymers remains a significant challenge in the commercialization of organic field-effect transistors (OFETs). To achieve this objective, it is essential to design the key electron-deficient units with simple molecular structure and facile preparation process, which can directly facilitate the production of low-cost n-type polymers. Herein, by sequentially introducing fluorine and cyano functionalities onto trans-1,3-butadiene π-skeleton, we developed a series of structurally simple but highly electron-deficient building blocks, namely 1,4-dicyano-butadienes (CNDE), 3-fluoro-1,4-dicyano-butadienes (CNFDE), and 2,3-difluoro-1,4-dicyano-butadienes (CNDFDE), featuring highly coplanar backbone and deep-positioned lowest unoccupied molecular orbital (LUMO) energy levels (-3.03-4.33 eV), which render them highly attractive building blocks for developing n-type semiconducting polymers. Notably, all these electron-deficient units can be easily accessed via a two-step high-yield synthetic protocol from low-cost raw materials, thus rendering them highly promising candidates for commercial applications. Upon polymerized with diketopyrrolopyrrole (DPP) units, three copolymers are developed and demonstrated unipolar n-type transport characteristics in OFETs with the highest electron mobility > 1 cm2 V-1 s-1. Hence, CNDE, CNFDE, and CNDFDE represent a class of novel, simple, and efficient electron-deficient units for constructing low-cost n-type polymers, providing valuable insights for the OFET applications.