%0 Journal Article
%T Drastic Improvement of Air Stability in an n-Type Doped Naphthalene-Diimide Polymer by Thionation
%J -
%D 2018
%R https://doi.org/10.1021/acsaem.8b00777
%X High Resolution Image Download MS PowerPoint Slide Organic thermoelectrics are attractive for the fabrication of flexible and cost-effective thermoelectric generators (TEGs) for waste heat recovery, in particular by exploiting large-area printing of polymer conductors. Efficient TEGs require both p- and n-type conductors: so far, the air instability of polymer n-type conductors, which typically lose orders of magnitude in electrical conductivity (¦Ò) even for short exposure time to air, has impeded processing under ambient conditions. Here we tackle this problem in a relevant class of electron transporting, naphthalene-diimide copolymers, by substituting the imide oxygen with sulfur. n-type doping of the thionated copolymer gives rise to a higher ¦Ò with respect to the non-thionated one, and most importantly, owing to a reduced energy level of the lowest-unoccupied molecular orbital, ¦Ò is substantially stable over 16 h of air exposure. This result highlights the effectiveness of chemical tuning to improve air stability of n-type solution-processable polymer conductors and shows a path toward ambient large-area manufacturing of efficient polymer TEGs
%U https://pubs.acs.org/doi/10.1021/acsaem.8b00777