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Title: Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy

Abstract

Lead halide perovskite semiconductors have low-frequency phonon modes within the lead halide sublattice and thus are considered to be soft. The soft lattice is considered to be important in defining their interesting optoelectronic properties. Electron-phonon coupling governs hot-carrier relaxation, carrier mobilities, carrier lifetimes, among other important electronic characteristics. Directly observing the interplay between free charge carriers and phonons can provide details on how phonons impact these properties (e.g., exciton populations and other collective modes). Here, we observe a delicate interplay among carriers, phonons, and excitons in mixed-cation and mixed-halide perovskite films by simultaneously resolving the contribution of charge carriers and phonons in time-resolved terahertz photoconductivity spectra. We are able to observe directly the increase in phonon population during carrier cooling and discuss how thermal equilibrium populations of carriers and phonons modulate the carrier transport properties, as well as reduce the population of carriers within band tails. We are also able to observe directly the formation of free charge carriers when excitons interact with phonons and dissociate and to describe how free carriers and exciton populations exchange through phonon interactions. Finally, we also time-resolve how the carriers are screened via the Coulomb interaction at low and room temperatures. Our studies shedmore » light on how charge carriers interact with the low-energy phonons and discuss implications.« less

Authors:
 [1];  [1];  [1];  [2];  [1];  [1];  [3];  [4]; ORCiD logo [5];  [1]
  1. Nanyang Technological University
  2. Nanyang Technological University; California Institute of Technology
  3. Los Alamos National Laboratory
  4. King Monghut's University of Technology Thonburi
  5. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1550786
Report Number(s):
NREL/JA-5900-72381
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
ACS Nano
Additional Journal Information:
Journal Name: ACS Nano
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; perovskite; time-resolved terahertz spectroscopy; phonon; free carrier; exciton

Citation Formats

Zhao, Daming, Hu, Hongwei, Haselsberger, Reinhard, Marcus, Rudolph A., Michel-Beyerle, Maria-Elisabeth, Lam, Yeng Ming, Zhu, Jian-Xin, La-o-vorakiat, Chan, Beard, Matthew C, and Chia, Elbert E. M. Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy. United States: N. p., 2019. Web. doi:10.1021/acsnano.9b02049.
Zhao, Daming, Hu, Hongwei, Haselsberger, Reinhard, Marcus, Rudolph A., Michel-Beyerle, Maria-Elisabeth, Lam, Yeng Ming, Zhu, Jian-Xin, La-o-vorakiat, Chan, Beard, Matthew C, & Chia, Elbert E. M. Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy. United States. doi:10.1021/acsnano.9b02049.
Zhao, Daming, Hu, Hongwei, Haselsberger, Reinhard, Marcus, Rudolph A., Michel-Beyerle, Maria-Elisabeth, Lam, Yeng Ming, Zhu, Jian-Xin, La-o-vorakiat, Chan, Beard, Matthew C, and Chia, Elbert E. M. Fri . "Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy". United States. doi:10.1021/acsnano.9b02049.
@article{osti_1550786,
title = {Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy},
author = {Zhao, Daming and Hu, Hongwei and Haselsberger, Reinhard and Marcus, Rudolph A. and Michel-Beyerle, Maria-Elisabeth and Lam, Yeng Ming and Zhu, Jian-Xin and La-o-vorakiat, Chan and Beard, Matthew C and Chia, Elbert E. M.},
abstractNote = {Lead halide perovskite semiconductors have low-frequency phonon modes within the lead halide sublattice and thus are considered to be soft. The soft lattice is considered to be important in defining their interesting optoelectronic properties. Electron-phonon coupling governs hot-carrier relaxation, carrier mobilities, carrier lifetimes, among other important electronic characteristics. Directly observing the interplay between free charge carriers and phonons can provide details on how phonons impact these properties (e.g., exciton populations and other collective modes). Here, we observe a delicate interplay among carriers, phonons, and excitons in mixed-cation and mixed-halide perovskite films by simultaneously resolving the contribution of charge carriers and phonons in time-resolved terahertz photoconductivity spectra. We are able to observe directly the increase in phonon population during carrier cooling and discuss how thermal equilibrium populations of carriers and phonons modulate the carrier transport properties, as well as reduce the population of carriers within band tails. We are also able to observe directly the formation of free charge carriers when excitons interact with phonons and dissociate and to describe how free carriers and exciton populations exchange through phonon interactions. Finally, we also time-resolve how the carriers are screened via the Coulomb interaction at low and room temperatures. Our studies shed light on how charge carriers interact with the low-energy phonons and discuss implications.},
doi = {10.1021/acsnano.9b02049},
journal = {ACS Nano},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {7}
}