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Title: Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions

Abstract

In this paper, connecting the complex electronic excitations of hybrid perovskites to their intricate organic-inorganic lattice structure has critical implications for energy conversion and optoelectronic technologies. Here we detail the multiband, multivalley electronic structure of a halide hybrid perovskite by measuring the absorption transients of a millimeter-scale-grain thin film as it undergoes a thermally controlled reversible tetragonal-to-orthogonal phase transition. Probing nearly single grains of this hybrid perovskite, we observe an unreported energy splitting (degeneracy lifting) of the high-energy 2.6 eV band in the tetragonal phase that further splits as the rotational degrees of freedom of the disordered CH 3NH 3 + molecules are reduced when the sample is cooled. This energy splitting drastically increases during an extended phase-transition coexistence region that persists from 160 to 120 K, becoming more pronounced in the orthorhombic phase. By tracking the temperature-dependent optical transition energies and using symmetry analysis that describes the evolution of electronic states from the tetragonal phase to the orthorhombic phase, we assign this energy splitting to the nearly degenerate transitions in the tetragonal phase from both the R- and M-point-derived states. Importantly, these assignments explain how momentum conservation effects lead to long hot-carrier lifetimes in the room-temperature tetragonal phase, withmore » faster hot-carrier relaxation when the hybrid perovskite structurally transitions to the orthorhombic phase due to enhanced scattering at the Γ point.« less

Authors:
 [1];  [2];  [2];  [3];  [2]; ORCiD logo [4]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States); Univ. of Alabama at Birmingham, Birmingham, AL (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. CNRS, INSA de Rennes, Rennes (France)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1437444
Alternate Identifier(s):
OSTI ID: 1410471
Report Number(s):
BNL-204648-2018-JAAM
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:
SC0012704; 08SPCE973; AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 96; Journal Issue: 19; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Appavoo, Kannatassen, Nie, Wanyi, Blancon, Jean -Christophe, Even, Jacky, Mohite, Aditya D., and Sfeir, Matthew Y.. Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.96.195308.
Appavoo, Kannatassen, Nie, Wanyi, Blancon, Jean -Christophe, Even, Jacky, Mohite, Aditya D., & Sfeir, Matthew Y.. Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions. United States. doi:10.1103/PhysRevB.96.195308.
Appavoo, Kannatassen, Nie, Wanyi, Blancon, Jean -Christophe, Even, Jacky, Mohite, Aditya D., and Sfeir, Matthew Y.. Wed . "Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions". United States. doi:10.1103/PhysRevB.96.195308.
@article{osti_1437444,
title = {Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions},
author = {Appavoo, Kannatassen and Nie, Wanyi and Blancon, Jean -Christophe and Even, Jacky and Mohite, Aditya D. and Sfeir, Matthew Y.},
abstractNote = {In this paper, connecting the complex electronic excitations of hybrid perovskites to their intricate organic-inorganic lattice structure has critical implications for energy conversion and optoelectronic technologies. Here we detail the multiband, multivalley electronic structure of a halide hybrid perovskite by measuring the absorption transients of a millimeter-scale-grain thin film as it undergoes a thermally controlled reversible tetragonal-to-orthogonal phase transition. Probing nearly single grains of this hybrid perovskite, we observe an unreported energy splitting (degeneracy lifting) of the high-energy 2.6 eV band in the tetragonal phase that further splits as the rotational degrees of freedom of the disordered CH3NH3+ molecules are reduced when the sample is cooled. This energy splitting drastically increases during an extended phase-transition coexistence region that persists from 160 to 120 K, becoming more pronounced in the orthorhombic phase. By tracking the temperature-dependent optical transition energies and using symmetry analysis that describes the evolution of electronic states from the tetragonal phase to the orthorhombic phase, we assign this energy splitting to the nearly degenerate transitions in the tetragonal phase from both the R- and M-point-derived states. Importantly, these assignments explain how momentum conservation effects lead to long hot-carrier lifetimes in the room-temperature tetragonal phase, with faster hot-carrier relaxation when the hybrid perovskite structurally transitions to the orthorhombic phase due to enhanced scattering at the Γ point.},
doi = {10.1103/PhysRevB.96.195308},
journal = {Physical Review B},
number = 19,
volume = 96,
place = {United States},
year = {Wed Nov 15 00:00:00 EST 2017},
month = {Wed Nov 15 00:00:00 EST 2017}
}

Journal Article:
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