Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Drastic Improvement of Air Stability in an n-type Doped
  Naphtalene-diimide Polymer by Thionation   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 loose orders of magnitude in
electrical conductivity ({\sigma}) 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 co-polymers, by
substituting the imide oxygen with sulphur. n-type doping of the thionated
co-polymer gives rise to a higher {\sigma} with respect to the non-thionated
one, and most importantly, owing to a reduced energy level of the
lowest-unoccupied molecular orbital, {\sigma} 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 towards ambient large-area manufacturing of efficient polymer
TEGs.

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The categories of this paper are: q-bio
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ