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Title: Excitonic Effects in Methylammonium Lead Halide Perovskites

The exciton binding energy in methylammonium lead iodide (MAPbI3) is about 10 meV, around 1/3 of the available thermal energy (k BT ~ 26 meV) at room temperature. Thus, exciton populations are not stable at room temperature at moderate photoexcited carrier densities. However, excitonic resonances dominate the absorption onset. Furthermore, these resonances determine the transient absorbance and transient reflectance spectra. The exciton binding energy is a reflection of the Coulomb interaction energy between photoexcited electrons and holes. As such, it serves as a marker for the strength of electron/hole interactions and impacts a variety of phenomena, such as, absorption, radiative recombination, and Auger recombination. In this Perspective, we discuss the role of excitons and excitonic resonances in the optical properties of lead-halide perovskite semiconductors. Finally, we discuss how the strong light-matter interactions induce an optical stark effect splitting the doubly spin degenerate ground exciton states and are easily observed at room temperature.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ;  [1] ; ORCiD logo [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5900-71519
Journal ID: ISSN 1948-7185
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 9; Journal Issue: 10; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; excitons; excitonic resonances; optical properties; perovskite semiconductors
OSTI Identifier:
1437220

Chen, Xihan, Lu, Haipeng, Yang, Ye, and Beard, Matthew C. Excitonic Effects in Methylammonium Lead Halide Perovskites. United States: N. p., Web. doi:10.1021/acs.jpclett.8b00526.
Chen, Xihan, Lu, Haipeng, Yang, Ye, & Beard, Matthew C. Excitonic Effects in Methylammonium Lead Halide Perovskites. United States. doi:10.1021/acs.jpclett.8b00526.
Chen, Xihan, Lu, Haipeng, Yang, Ye, and Beard, Matthew C. 2018. "Excitonic Effects in Methylammonium Lead Halide Perovskites". United States. doi:10.1021/acs.jpclett.8b00526.
@article{osti_1437220,
title = {Excitonic Effects in Methylammonium Lead Halide Perovskites},
author = {Chen, Xihan and Lu, Haipeng and Yang, Ye and Beard, Matthew C.},
abstractNote = {The exciton binding energy in methylammonium lead iodide (MAPbI3) is about 10 meV, around 1/3 of the available thermal energy (kBT ~ 26 meV) at room temperature. Thus, exciton populations are not stable at room temperature at moderate photoexcited carrier densities. However, excitonic resonances dominate the absorption onset. Furthermore, these resonances determine the transient absorbance and transient reflectance spectra. The exciton binding energy is a reflection of the Coulomb interaction energy between photoexcited electrons and holes. As such, it serves as a marker for the strength of electron/hole interactions and impacts a variety of phenomena, such as, absorption, radiative recombination, and Auger recombination. In this Perspective, we discuss the role of excitons and excitonic resonances in the optical properties of lead-halide perovskite semiconductors. Finally, we discuss how the strong light-matter interactions induce an optical stark effect splitting the doubly spin degenerate ground exciton states and are easily observed at room temperature.},
doi = {10.1021/acs.jpclett.8b00526},
journal = {Journal of Physical Chemistry Letters},
number = 10,
volume = 9,
place = {United States},
year = {2018},
month = {5}
}