Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Identification of Two Regimes of Carrier Thermalization in PbS
  Nanocrystal Assemblies   We bring fresh insight into the ensemble properties of PbS colloidal quantum
dots with a critical review of the literature on semiconductors followed by
systematic comparisons between steady-state photocurrent and photoluminescence
measurements. Our experiments, performed with sufficiently low powers to
neglect nonlinear effects, indicate that the photoluminescence spectra have no
other noticeable contribution beside the radiative recombination of thermalized
photocarriers (i.e. photocarriers in thermodynamic quasi-equilibrium). A
phenomenological model based on the local Kirchhoff law is proposed that makes
it possible to identify the nature of the thermalized photocarriers and to
extract their temperatures from the measurements. Two regimes are observed: for
highly compact assemblies of PbS quantum dots stripped from organic ligands,
the thermalization concerns photocarriers distributed over a wide energy range.
With PbS quantum dots cross-linked with 1,2-ethanedithiol or longer organic
ligand chains, the thermalization concerns solely the fundamental exciton and
can quantitatively explain all the observations, including the precise Stokes
shift between the absorbance and luminescence maxima.

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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: eess