Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: MoS2 Quantum Dot/Graphene Hybrids for Advanced Interface Engineering of
  CH3NH3PbI3 Perovskite Solar Cell with Efficiency over 20%   Interface engineering of organic-inorganic halide perovskite solar cells
(PSCs) plays a pivotal role in achieving high power conversion efficiency
(PCE). Graphene and related two-dimensional materials (GRMs) are promising
candidates to tune on demand the interface properties of PSCs. In this work, we
fully exploit the potential of GRMs by controlling the optoelectronic
properties of hybrids between molybdenum disulfide (MoS2) and reduced graphene
oxide (RGO) as hole transport layer (HTL) and active buffer layer (ABL) in
mesoscopic methylammonium lead iodide (CH3NH3PbI3) perovskite (MAPbI3)-based
PSC. We show that zero-dimensional MoS2 quantum dots (MoS2 QDs), derived by
liquid phase exfoliated MoS2 flakes, provide both hole-extraction and
electron-blocking properties. In fact, on the one hand, intrinsic n-type
doping-induced intra-band gap states effectively extract the holes through an
electron injection mechanism. On the other hand, quantum confinement effects
increase the optical band gap of MoS2 (from 1.4 eV for the flakes to > 3.2 for
QDs), raising the minimum energy of its conduction band (from -4.3 eV for the
flakes to -2.2 eV for QDs) above the one of conduction band of MAPbI3 (between
-3.7 and -4 eV) and hindering electron collection. The van der Waals
hybridization of MoS2 QDs with functionalized reduced graphene oxide (f-RGO),
obtained by chemical silanization-induced linkage between RGO and
(3-mercaptopropyl)trimethoxysilane, is effective to homogenize the deposition
of HTLs or ABLs onto the perovskite film, since the two-dimensional (2D) nature
of RGO effectively plug the pinholes of the MoS2 QDs films. Our graphene
interface engineering (GIE) strategy based on van der Waals MoS2 QD/graphene
hybrids enable MAPbI3-based PSCs to achieve PCE up to 20.12% (average PCE of
18.8%).

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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga