TY - JOUR
T1 - Understanding Instability in Formamidinium Lead Halide Perovskites
T2 - Kinetics of Transformative Reactions at Grain and Subgrain Boundaries
AU - Raval, Parth
AU - Kennard, Rhiannon M.
AU - Vasileiadou, Eugenia S.
AU - Dahlman, Clayton J.
AU - Spanopoulos, Ioannis
AU - Chabinyc, Michael L.
AU - Kanatzidis, Mercouri
AU - Manjunatha Reddy, G. N.
N1 - Funding Information:
At Northwestern University and UCSB, this work is mainly supported by the Department of Energy, Office of Science, Basic Energy Sciences, under Grant No. SC0012541 (synthesis, structure, and characterization of physical properties). The research reported here also made use the shared facilities of the UCSB MRSEC (National Science Foundation DMR 1720256), a member of the Materials Research Facilities Network ( www.mrfn.org ). R.M.K. gratefully acknowledges the National Defense Science and Engineering Graduate fellowship for financial support. G.N.M.R. and P.R. acknowledge the funding from University of Lille and region Hauts-de-France (HDF). G.N.M.R. acknowledges the funding from I-SITE ULNE International Mobility Grant and EU-H2020 research and innovation programme under the Marie Skłodowska-Curie Grant 795091.
Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/4/8
Y1 - 2022/4/8
N2 - Transformative and reconstructive reactions impart significant structural changes at particle boundaries of hybrid perovskites, which influence environmental stability and optoelectronic properties of these materials. Here, we investigate the moisture-induced transformative reactions in formamidinium(FA)-based perovskites FAPbX3(X = I, Br) and show that the ambient stability of these materials can be adjusted from a few hours to several months. For FAPbI3, roles of water vapor, particle size, and light illumination on the kinetic pathways of the cubic (α) transformation to the hexagonal (δ) phase are analyzed by X-ray diffraction, optical microscopy, photoluminescence, and solid-state (ss) NMR spectroscopy techniques. The grain and subgrain boundaries exhibit different α- → δ-FAPbI3phase transformation kinetics. Our study suggests that the dynamic transformation involves the local water-induced dissolution of the cubic phase occurring at the crystal surfaces followed by precipitation of the hexagonal phase. Insights into structures and dynamics of a kinetically trapped α-|δ-FAPbI3are obtained by 1H, 2H, and 207Pb ssNMR spectroscopy.
AB - Transformative and reconstructive reactions impart significant structural changes at particle boundaries of hybrid perovskites, which influence environmental stability and optoelectronic properties of these materials. Here, we investigate the moisture-induced transformative reactions in formamidinium(FA)-based perovskites FAPbX3(X = I, Br) and show that the ambient stability of these materials can be adjusted from a few hours to several months. For FAPbI3, roles of water vapor, particle size, and light illumination on the kinetic pathways of the cubic (α) transformation to the hexagonal (δ) phase are analyzed by X-ray diffraction, optical microscopy, photoluminescence, and solid-state (ss) NMR spectroscopy techniques. The grain and subgrain boundaries exhibit different α- → δ-FAPbI3phase transformation kinetics. Our study suggests that the dynamic transformation involves the local water-induced dissolution of the cubic phase occurring at the crystal surfaces followed by precipitation of the hexagonal phase. Insights into structures and dynamics of a kinetically trapped α-|δ-FAPbI3are obtained by 1H, 2H, and 207Pb ssNMR spectroscopy.
UR - http://www.scopus.com/inward/record.url?scp=85127952914&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85127952914&partnerID=8YFLogxK
U2 - 10.1021/acsenergylett.2c00140
DO - 10.1021/acsenergylett.2c00140
M3 - Article
AN - SCOPUS:85127952914
SN - 2380-8195
VL - 7
SP - 1534
EP - 1543
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 4
ER -
