Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polaron Recombination in Pristine and Annealed Bulk Heterojunction Solar
  Cells   We determined the dominant polaron recombination loss mechanism in pristine
and annealed polythiophene:fullerene blend solar cells by applying the
photo-induced charge extraction by linearly increasing voltage (photo-CELIV)
method in dependence on temperature. In pristine samples, we find a strongly
temperature dependent bimolecular polaron recombination rate, which is reduced
as compared to the Langevin theory. For the annealed sample, we observe a
polaron decay rate which follows a third order of carrier concentration almost
temperature independently.

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The categories of this paper are: patt-sol
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg