Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Charge Transport Properties of a Metal-free Phthalocyanine Discotic
  Liquid Crystal   Discotic liquid crystals can self-align to form one-dimensional
semiconducting wires, many tens of microns long. In this letter, we describe
the preparation of semiconducting films where the stacking direction of the
disc-like molecules is perpendicular to the substrate surface. We present
measurements of the charge carrier mobility, applying temperature-dependent
time-of-flight transient photoconductivity, space-charge limited current
measurements, and field-effect mobility measurements. We provide experimental
verification of the highly anisotropic nature of semiconducting films of
discotic liquid crystals, with charge carrier mobilities of up to
2.8x10$^{-3}$cm$^2$/Vs. These properties make discotics an interesting choice
for applications such as organic photovoltaics.

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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: eess