Record High Electron Mobility Exceeding 16 cm 2 V -1 s -1 in Bisisoindigo-Based Polymer Semiconductor with a Fully Locked Conjugated Backbone.

Polymer semiconductors with mobilities exceeding 10 cm 2 V -1 s -1 , especially ambipolar and n-type polymer semiconductors, are still rare, although they are of great importance for fabricating polymer field-effect transistors (PFETs) toward commercial high-grade electronics. Herein, we designed and synthesized two novel donor-acceptor copolymers PNFFN-DTE and PNFFN-FDTE based on the electron-deficient bisisoindigo (NFFN) and electron-rich dithienylethylenes (DTE or FDTE). The copolymer PNFFN-DTE containing NFFN and DTE possesses a partially locked polymeric conjugated backbone whereas PNFFN-FDTE containing NFFN and FDTE own a fully locked one. Fluorine atoms in FDTE not only induce the formation of additional CH∙∙∙F hydrogen bonds but also lower frontier molecular orbitals for PNFFN-FDTE. Both PNFFN-DTE and PNFFN-FDTE formed more ordered molecular packing in thin films prepared from a polymer solution in bi-component solvent containing 1,2-dichlorobenzene (DCB) and 1-chloronaphthalene (with volume ratio of 99.2/0.8) than pure DCB. The two copolymers-based flexible PFETs exhibited ambipolar charge transport properties. Notably, the bi-component solvent-processed PNFFN-FDTE-based PFETs afforded a high electron mobility of 16.67 cm 2 V -1 s -1 , which is the highest electron transport mobility for the PFETs reported so far. We attributed the high electron mobility of PNFFN-FDTE to its fully locked conjugated backbone, dense molecular packing, and much matched LUMO energy level. This article is protected by copyright. All rights reserved.