Chlorinated Conjugated Polymer Based on Chlorine- and Cyano-substituted (E)-1,2-Di(thiophen-2-yl)ethane for Ambipolar and n-Type Organic Thin-film Transistors

Comprehensive Summary Chlorinated conjugated polymers are rarely reported in ambipolar and n-type organic thin-film transistors (OTFTs), mainly due to the lack of chlorinated strong electron-deficient building blocks. Herein, we report three new chlorine (Cl)- and cyano (CN)- substituted (E)-1,2-di(thiophen-2-yl)ethane building blocks and their copolymers P2Cl1CNTVT-DPP, P4Cl1CNTVT-DPP and P2Cl2CNTVT-DPP. P2Cl1CNTVT-DPP and P2Cl2CNTVT-DPP had nearly planar backbone geometries, mixture of edge-on and face-on orientation and deeper energy levels, while P4Cl1CNTVT-DPP had a twist backbone geometry, face-on orientation and shallower energy levels. As a result, P2Cl1CNTVT-DPP exhibited ambipolar characteristic with hole mobility (mu(h)) of 0.70 cm(2)center dot V-1 center dot s(-1) and electron mobility (mu(e)) of 0.84 cm(2)center dot V-1 center dot s(-1) and P2Cl2CNTVT-DPP exhibited n-type characteristic with mu(e) of 0.64 cm(2)center dot V-1 center dot s(-1), while P4Cl1CNTVT-DPP exhibited the lowest mu(e) of 0.36 cm(2)center dot V-1 center dot s(-1). The devices based on P2Cl2CNTVT-DPP exhibited good stability after being stored for 10 d in air. The results demonstrate that by rational molecular design, chlorinated polymers with low cost can be applied to high-performance ambipolar and n-type OTFTs.

Automated summary

This study reports the performance of three new chlorine and cyano substituted building blocks and their copolymers in organic thin-film transistors. The results demonstrate that by rational molecular design, chlorinated polymers can be applied to high-performance ambipolar and n-type OTFTs.