A High-Performance n-Type Thermoelectric Polymer from C-H/C-H Oxidative Direct Arylation Polycondensation.

ABSTRACT

n-Type conjugated polymers (CPs) are crucial in the applications of organic electronics. Direct coupling of electron-deficient C-H monomer via selective C-H activation, namely C-H/C-H oxidative direct arylation polycondensation (Oxi-DArP), is an ideal approach toward such CPs. Herein, Oxi-DArP is firstly adopted to synthesize a high-performance n-type CP using a newly developed monomer, i.e., 3,6-di(thiazol-5-yl)-diketopyrrolopyrrole (Tz-5-DPP). Tz-5-DPP based homopolymer PTz-5-DPP with a molecular weight of 22 kDa has been synthesized via Oxi-DArP. After n-doping, PTz-5-DPP films exhibited electric conductivity values up to 8 S cm-1 and power factors (PFs) up to 106 µW m-1 K-2 . Notably, this PF value is the highest for n-type polymer thermoelectric materials to date. The Oxi-DArP synthesis and the excellent n-type performance of the polymer make this work an important step toward the straightforward and sustainable preparation of high-performance n-type polymer semiconductors.