Enhanced n-Doping Efficiency of a Naphthalenediimide-Based Copolymer through Polar Side Chains for Organic Thermoelectrics
Journal article, 2018

N-doping of conjugated polymers either requires a high dopant fraction or yields a low electrical conductivity because of their poor compatibility with molecular dopants. We explore n-doping of the polar naphthalenediimide–bithiophene copolymer p(gNDI-gT2) that carries oligoethylene glycol-based side chains and show that the polymer displays superior miscibility with the benzimidazole–dimethylbenzenamine-based n-dopant N-DMBI. The good compatibility of p(gNDI-gT2) and N-DMBI results in a relatively high doping efficiency of 13% for n-dopants, which leads to a high electrical conductivity of more than 10–1 S cm–1 for a dopant concentration of only 10 mol % when measured in an inert atmosphere. We find that the doped polymer is able to maintain its electrical conductivity for about 20 min when exposed to air and recovers rapidly when returned to a nitrogen atmosphere. Overall, solution coprocessing of p(gNDI-gT2) and N-DMBI results in a larger thermoelectric power factor of up to 0.4 μW K–2 m–1 compared to other NDI-based polymers.

oligo ethylene glycol side chains

electrical conductivity


n-type organic thermoelectrics

doping efficiency


David Kiefer

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Alexander Giovannitti

Imperial College London

Hengda Sun

Linköping University

Till Biskup

University of Freiburg

Anna Hofmann

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Marten Koopmans

Camila Cendra

Stanford University

Stefan Weber

University of Freiburg

L. Jan Anton Koster

Eva Olsson

Chalmers, Physics, Eva Olsson Group

Jonathan Rivnay

Northwestern University

Simone Fabiano

Linköping University

Iain McCulloch

King Abdullah University of Science and Technology (KAUST)

Imperial College London

Christian Müller

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

ACS Energy Letters

23808195 (eISSN)

Vol. 3 2 278-285

Subject Categories

Polymer Chemistry

Textile, Rubber and Polymeric Materials

Other Physics Topics


Chalmers Materials Analysis Laboratory

Areas of Advance

Materials Science



More information

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1/3/2024 9