Authors Matsidik, R. ; Komber, H. ; Luzio, A. ; Caironi, M. ; Sommer, M.
Title Defect-free naphthalene diimide bithiophene copolymers with controlled molar mass an high performance via direct arylation polycondensation
Date 01.06.2015
Number 46026
Abstract A highly efficient, simple, and environmentally friendly protocol for the synthesis of an alternating naphthalene diimide bithiophene copolymer (PNDIT2) via direct arylation polycondensation (DAP) is presented. High molecular weight (MW) PNDIT2 can be obtained in quantitative yield using aromatic solvents. Most critical is the suppression of two major termination reactions of NDIBr end groups: nucleophilic substitution and solvent end-capping by aromatic solvents via C–H activation. In situ solvent end-capping can be used to control MW by varying monomer concentration, whereby end-capping is efficient and MW is low for low concentration and vice versa. Reducing C–H reactivity of the solvent at optimized conditions further increases MW. Chain perfection of PNDIT2 is demonstrated in detail by NMR spectroscopy, which reveals PNDIT2 chains to be fully linear and alternating. This is further confirmed by investigating the optical and thermal properties as a function of MW, which saturate at Mn ˜ 20 kDa, in agreement with controls made by Stille coupling. Field-effect transistor (FET) electron mobilities µsat up to 3 cm2/(V·s) are measured using off-center spin-coating, with FET devices made from DAP PNDIT2 exhibiting better reproducibility compared to Stille controls.
Publisher Journal of the American Chemical Society
Citation Journal of the American Chemical Society 137 (2015) 6705-6711

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