Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bright Luminescent Surface States on the Edges of Wide-bandgap
  Two-dimensional Lead Halide Perovskite   Three-dimensional lead halide perovskites have surprised people for their
defect-tolerant electronic and optical properties, two-dimensional lead halide
layered structures exhibit even more puzzling phenomena: luminescent edge
states in Ruddlesden-Popper perovskites and conflicting reports of highly
luminescent versus non-emissive CsPb$_{\text{2}}$Br$_{\text{5}}$. In this work,
we report the observation of bright luminescent surface states on the edges of
CsPb$_{\text{2}}$Br$_{\text{5}}$ microplatelets. We prove that green surface
emission makes wide-bandgap single crystal CsPb$_{\text{2}}$Br$_{\text{5}}$
highly luminescent. Using polarized Raman spectroscopy and atomic-resolution
transmission electron microscopy, we further prove that polycrystalline
CsPb$_{\text{2}}$Br$_{\text{5}}$ is responsible for the bright luminescence. We
propose that these bright edge states originate from corner-sharing clusters of
PbBr$_{\text{6}}$ in the distorted regions between
CsPb$_{\text{2}}$Br$_{\text{5}}$ nanocrystals. Because metal halide octahedrons
are building blocks of perovskites, our discoveries settle a long-standing
controversy over the basic property of CsPb$_{\text{2}}$Br$_{\text{5}}$ and
open new opportunities to understand, design and engineer perovskite solar
cells and other optoelectronic devices.

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The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys