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-doping
n-type organic thermoelectrics
doping efficiency
Author
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 2 278-285Subject Categories
Polymer Chemistry
Textile, Rubber and Polymeric Materials
Other Physics Topics
Infrastructure
Chalmers Materials Analysis Laboratory
Areas of Advance
Materials Science
DOI
10.1021/acsenergylett.7b01146