Abstract
The search for new halide perovskites has recently expanded to the double perovskites A2M+M3+X6, which form in the 3D elpasolite structure with alternating M+ and M3+ octahedra. Here, we report the ternary mixed-valent indium compounds CsInX3 (X = Br, Cl). They adopt a tetragonal (space group I4/m) structure, which is a derivative of the charge-ordered double perovskite but with a twisted chain of octahedra along the c-axis. This twist is a result of the off-centering at the In+ site to accommodate its stereochemically active 5s2 lone pair, which induces a 45° rotation of all In3+ octahedra in the chain. This is a non-cooperative rotation that creates pentagonal pyramids in the structure and induces significant disorder, with extensive twinning, which results in partial occupation of different rotations of the same In3+ site. Temperature-dependent synchrotron X-ray diffraction reveals that both compounds form the cubic double perovskite structure at high temperature (Fm3̄ m), thus demonstrating that the twist occurs on cooling from the melt. UV-vis spectroscopy reveals band gaps near 2.3-2.4 eV for the bromide and 3.0 eV for CsInCl3. High-pressure electrical transport measurements show significant enhancement in conductivity as pressure increases, indicating a narrowing of the band gap at high pressures. Temperature-dependent transport measurements at high pressure show uniformly semiconducting behavior, with no superconducting transition observed down to 2.4 K. The CsInX3 are unique inorganic halide double perovskites because they are based on a single metal, with CsInBr3 just the third bromide after the mixed metal compounds Cs2AgBiBr6 and Cs2AgTlBr6.
Original language | English (US) |
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Pages (from-to) | 9554-9566 |
Number of pages | 13 |
Journal | Chemistry of Materials |
Volume | 31 |
Issue number | 22 |
DOIs | |
State | Published - Nov 26 2019 |
Funding
This work is primarily supported by the Department of Homeland Security ARI program under grant 2014-DN-077-ARI086-01. Some of the crystallographic aspects of this work were supported by the Department of Energy Office of Science (grant SC0012541). Use of beamline 11-BM-B at the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. This work made use of the IMSERC at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the State of Illinois and International Institute for Nanotechnology (IIN). This work made use of the EPIC and SPID facilities of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Materials Chemistry
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Dive into the research topics of 'Perovskites with a Twist: Strong In1+ Off-Centering in the Mixed-Valent CsInX3 (X = Cl, Br)'. Together they form a unique fingerprint.Datasets
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CSD 1990663: Experimental Crystal Structure Determination
Mccall, K. M. (Contributor), Friedrich, D. (Contributor), Chica, D. G. (Contributor), Cai, W. (Contributor), Stoumpos, C. C. (Contributor), Alexander, G. C. B. (Contributor), Deemyad, S. (Contributor), Wessels, B. W. (Contributor) & Kanatzidis, M. G. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc24tfyc, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc24tfyc&sid=DataCite
Dataset
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CSD 1990662: Experimental Crystal Structure Determination
Mccall, K. M. (Contributor), Friedrich, D. (Contributor), Chica, D. G. (Contributor), Cai, W. (Contributor), Stoumpos, C. C. (Contributor), Alexander, G. C. B. (Contributor), Deemyad, S. (Contributor), Wessels, B. W. (Contributor) & Kanatzidis, M. G. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc24tfxb, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc24tfxb&sid=DataCite
Dataset
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CSD 1990665: Experimental Crystal Structure Determination
Mccall, K. M. (Contributor), Friedrich, D. (Contributor), Chica, D. G. (Contributor), Cai, W. (Contributor), Stoumpos, C. C. (Contributor), Alexander, G. C. B. (Contributor), Deemyad, S. (Contributor), Wessels, B. W. (Contributor) & Kanatzidis, M. G. (Contributor), FIZ Karlsruhe - Leibniz Institute for Information Infrastructure, 2019
DOI: 10.25505/fiz.icsd.cc24tg0g, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc24tg0g&sid=DataCite
Dataset