Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic Trap States in Methanofullerenes   The trap states in three fullerene derivatives, namely PC61BM ([6,6]-phenyl
C61 butyric acid methyl ester), bisPC61BM (bis[6,6]-phenyl C61 butyric acid
methyl ester) and PC71BM ([6,6]-phenyl C71 butyric acid methyl ester), are
investigated by thermally stimulated current measurements (TSC). Thereby, the
lower limit of the trap densities for all studied methanofullerenes exhibits
values in the order of 10^22 m^-3 with the highest trap density in bisPC61BM
and the lowest in PC61BM. Fractional TSC measurements on PC61BM reveal a broad
trap distribution instead of discrete trap levels with activation energies
ranging from 15 meV to 270 meV and the maximum at about 75 meV. The activation
energies of the most prominent traps in the other two fullerene derivatives are
significantly higher, being at 96 meV and 223 meV for PC71BM and 184 meV for
bisPC61BM, respectively. The influence of these findings on the performance of
organic solar cells is discussed.

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The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: econ
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio