Unveiling the Photo- and Thermal-Stability of Cesium Lead Halide Perovskite Nanocrystals

Article abstract of DOI:10.1002/cphc.201900432

Lead halide perovskites possess unique characteristics that are well-suited for optoelectronic and energy capture devices, however, concerns about their long-term stability remain. Limited stability is often linked to the methylammonium cation, and all-inorganic CsPbX₃ (X=Cl, Br, I) perovskite nanocrystals have been reported with improved stability. In this work, the photostability and thermal stability properties of CsPbX₃ (X=Cl, Br, I) nanocrystals were investigated by means of electron microscopy, X-ray diffraction, thermogravimetric analysis coupled with FTIR (TGA-FTIR), ensemble and single particle spectral characterization. CsPbBr₃ was found to be stable under 1-sun illumination for 16 h in ambient conditions, although single crystal luminescence analysis after illumination using a solar simulator indicates that the luminescence states are changing over time. CsPbBr₃ was also stable to heating to 250 °C. Large CsPbI₃ crystals (34±5 nm) were shown to be the least stable composition under the same conditions as both XRD reflections and Raman bands diminish under irradiation; and with heating the γ (black) phase reverts to the non-luminescent δ phase. Smaller CsPbI₃ nanocrystals (14±2 nm) purified by a different washing strategy exhibited improved photostability with no evidence of crystal growth but were still thermally unstable. Both CsPbCl₃ and CsPbBr₃ show crystal growth under irradiation or heat, likely with a preferential orientation based on XRD patterns. TGA-FTIR revealed nanocrystal mass loss was only from liberation and subsequent degradation of surface ligands. Encapsulation or other protective strategies should be employed for long-term stability of these materials under conditions of high irradiance or temperature.

Full text of DOI:10.1002/cphc.201900432

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
Accepted Article
Title: Unveiling the Photo- and Thermal-Stability of Cesium Lead
Halide Perovskite Nanocrystals
Authors: Brett W. Boote, Himashi P. Andaraarachchi, Bryan A.
Rosales, Rafael Blome-Fernández, Feng Zhu, Malinda D.
Reichert, Kalyan Santra, Jingzhe Li, Jacob W. Petrich, Javier
Vela, and Emily A. Smith
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: ChemPhysChem 10.1002/cphc.201900432
Link to VoR: http://dx.doi.org/10.1002/cphc.201900432
A Journal of
www.chemphyschem.org

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
10.1002/cphc.201900432
ChemPhysChem
Unveiling the Photo- and Thermal-Stability of Cesium Lead Halide Perovskite
Nanocrystals
Brett W. Boote,a,b Himashi P. Andaraarachchi,a,b Bryan A. Rosales,a Rafael Blome-Fernández,a
Feng Zhu,a Malinda D. Reichert,a Kalyan Santra,a,b Jingzhe Li,a,b Jacob W. Petrich,a,b Javier
Vela,a,b,* Emily A. Smitha,b,*
Affiliations
aDepartment of Chemistry, Iowa State University, and bAmes Laboratory, U.S. Department of
Energy, Ames, Iowa 50011-3111, United States
Abstract
Lead halide perovskites possess unique characteristics that are well-suited for
optoelectronic and energy capture devices, however, concerns about their long-term stability
remain. Limited stability is often linked to the methylammonium cation, and all-inorganic
CsPbX3 (X = Cl, Br, I) perovskite nanocrystals have been reported with improved stability. In
this work, the photostability and thermal stability properties of CsPbX3 (X = Cl, Br, I)
nanocrystals were investigated via electron microscopy, x-ray diffraction, thermogravimetric
analysis coupled with FTIR (TGA-FTIR), ensemble and single particle spectral characterization.
CsPbBr3 was found to be stable under 1-sun illumination for 16 h in ambient conditions,
although single crystal luminescence analysis after illumination via a solar simulator indicates
that the luminescence states are changing over time. CsPbBr3 was also stable to heating to 250
°C. Large CsPbI3 crystals (34 ± 5 nm) were shown to be the least stable composition under the
This article is protected by copyright. All rights reserved.

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
10.1002/cphc.201900432
ChemPhysChem
same conditions as both XRD reflections and Raman bands diminish under irradiation; and with
heating the g (black) phase reverts to the non-luminescent δ phase. Smaller CsPbI3 nanocrystals
(14 ± 2 nm) purified by a different washing strategy exhibited improved photostability with no
evidence of crystal growth but were still thermally unstable. Both CsPbCl3 and CsPbBr3 show
crystal growth under irradiation or heat, likely with a preferential orientation based on XRD
patterns. TGA-FTIR revealed nanocrystal mass loss was only from liberation and subsequent
degradation of surface ligands. Encapsulation or other protective strategies should be employed
for long-term stability of these materials under conditions of high irradiance or temperature.
Keywords
Lead halide perovskites, photostability, degradation, semiconductor nanocrystals, single crystal
luminescence
[a]
Dr. B. W. Boote, Dr. H. P. Andaraarachchi, Dr. B. A. Rosales, Mr. R. Blome-Fernández,
Dr. F. Zhu, Dr. M. D. Reichert, Mr. K. Santra, Ms. J. Li, Prof. Dr. J. W. Petrich, Prof. Dr. J.
Vela,* Prof. Dr. E. A. Smith*
Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
E-mail: esmith1@iastate.edu, vela@iastate.edu
[b]
Dr. B. W. Boote, Dr. H. P. Andaraarachchi, Mr. K. Santra, Ms. J. Li, Prof. Dr. J. W.
Petrich, Prof. Dr. J. Vela,* Prof. Dr. E. A. Smith*
The Ames Laboratory, U.S. Department of Energy, and Department of Chemistry, Iowa State
University, Ames, Iowa 50011, United States
This article is protected by copyright. All rights reserved.

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
10.1002/cphc.201900432
ChemPhysChem
E-mail: esmith1@iastate.edu, vela@iastate.edu
Supporting information for this article is given via a link at the end of the document.
ARTICLE
Brett W. Boote, Himashi P.
Andaraarachchi, Bryan A. Rosales,
Rafael Blome-Fernández, Feng Zhu,
Malinda D. Reichert, Kalyan Santra,
Jingzhe Li, Jacob W. Petrich, Javier
Vela,* Emily A. Smith*
Page No. – Page No.
Unveiling the Photo- and Thermal-
Stability of Cesium Lead Halide
Perovskite Nanocrystals
The photophysical properties of cesium lead halide nanocrystals show great
promise in derived devices due to high quantum yields and tunable visible
photoluminescence, but stability concerns remain. In this work, the photostability
and thermal stability of cesium lead halide nanocrystals were investigated using a
combination of X-ray diffraction, Raman spectroscopy, single crystal luminescence
imaging, and thermal gravimetric analysis. The observed changes in the
nanocrystals as a result of illumination and heating were found to be highly
dependent on halide composition.
This article is protected by copyright. All rights reserved.