Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Environmentally Stable and Lead-Free Chalcogenide Perovskite   Organic-inorganic halide perovskites are intrinsically unstable when exposed
to moisture and/or light. Additionally, the presence of lead in many
perovskites raises toxicity concerns. Herein is reported a thin film of BaZrS3,
a lead-free chalcogenide perovskite. Photoluminescence and X-ray diffraction
measurements show that BaZrS3 is far more stable than methylammonium lead
iodide (MAPbI3) in moist environments. Moisture- and light-induced degradations
in BaZrS3 and MAPbI3 are compared by using simulations and calculations based
on density functional theory. The simulations reveal drastically slower
degradation in BaZrS3 due to two factors - weak interaction with water, and
very low rates of ion migration. BaZrS3 photo-detecting devices with
photo-responsivity of ~46.5 mA W-1 are also reported. The devices retain ~60%
of their initial photo-response after 4 weeks in ambient conditions. Similar
MAPbI3 devices degrade rapidly and show ~95% decrease in photo-responsivity in
just 4 days. The findings establish the superior stability of BaZrS3 and
strengthen the case for its use in optoelectronics. New possibilities for
thermoelectric energy conversion using these materials are also demonstrated.

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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: econ
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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: hep-lat
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The categories of this paper are: patt-sol