Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Atomistic origins of high-performance in hybrid halide perovskite solar
  cells   The performance of organometallic perovskite solar cells has rapidly
surpassed that of both conventional dye-sensitised and organic photovoltaics.
High power conversion efficiency can be realised in both mesoporous and
thin-film device architectures. We address the origin of this success in the
context of the materials chemistry and physics of the bulk perovskite as
described by electronic structure calculations. In addition to the basic
optoelectronic properties essential for an efficient photovoltaic device
(spectrally suitable band gap, high optical absorption, low carrier effective
masses), the materials are structurally and compositionally flexible. As we
show, hybrid perovskites exhibit spontaneous electric polarisation; we also
suggest ways in which this can be tuned through judicious choice of the organic
cation. The presence of ferroelectric domains will result in internal junctions
that may aid separation of photoexcited electron and hole pairs, and reduction
of recombination through segregation of charge carriers. The combination of
high dielectric constant and low effective mass promotes both Wannier-Mott
exciton separation and effective ionisation of donor and acceptor defects. The
photoferroic effect could be exploited in nanostructured films to generate a
higher open circuit voltage and may contribute to the current-voltage
hysteresis observed in perovskite solar cells.

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The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex