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Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
Hybrid halide perovskites combine ease of preparation and relatively abundant constituent elements with fascinating photophysical properties. Descriptions of the chemical and structural drivers of the remarkable properties have often focused on the potential role of the dynamic order/disorder of the...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5621007/ https://www.ncbi.nlm.nih.gov/pubmed/28989600 http://dx.doi.org/10.1039/c7sc01429e |
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author | Laurita, Geneva Fabini, Douglas H. Stoumpos, Constantinos C. Kanatzidis, Mercouri G. Seshadri, Ram |
author_facet | Laurita, Geneva Fabini, Douglas H. Stoumpos, Constantinos C. Kanatzidis, Mercouri G. Seshadri, Ram |
author_sort | Laurita, Geneva |
collection | PubMed |
description | Hybrid halide perovskites combine ease of preparation and relatively abundant constituent elements with fascinating photophysical properties. Descriptions of the chemical and structural drivers of the remarkable properties have often focused on the potential role of the dynamic order/disorder of the molecular A-site cations. We reveal here a key aspect of the inorganic framework that potentially impacts the electronic, thermal, and dielectric properties. The temperature evolution of the X-ray pair distribution functions of hybrid perovskites ABX(3) [A(+) = CH(3)NH(3) (MA) or CH(NH(2))(2) (FA); B(2+) = Sn or Pb; X(–) = Br, or I] in their cubic phases above 300 K reveals temperature-activated displacement (off-centering) of the divalent group 14 cations from their nominal, centered sites. This symmetry-lowering distortion phenomenon, previously dubbed emphanisis in the context of compounds such as PbTe, is attributed to Sn(2+) and Pb(2+) lone pair stereochemistry. Of the materials studied here, the largest displacements from the center of the octahedral sites are found in tin iodides, a more moderate effect is found in lead bromides, and the weakest effect is seen in lead iodides. The A-site cation appears to play a role as well, with the larger FA resulting in greater off-centering for both Sn(2+) and Pb(2+). Dynamic off-centering, which is concealed within the framework of traditional Bragg crystallography, is proposed to play a key role in the remarkable defect-tolerant nature of transport in these semiconductors via its effect on the polarizability of the lattice. The results suggest a novel chemical design principle for future materials discovery. |
format | Online Article Text |
id | pubmed-5621007 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-56210072017-10-06 Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites Laurita, Geneva Fabini, Douglas H. Stoumpos, Constantinos C. Kanatzidis, Mercouri G. Seshadri, Ram Chem Sci Chemistry Hybrid halide perovskites combine ease of preparation and relatively abundant constituent elements with fascinating photophysical properties. Descriptions of the chemical and structural drivers of the remarkable properties have often focused on the potential role of the dynamic order/disorder of the molecular A-site cations. We reveal here a key aspect of the inorganic framework that potentially impacts the electronic, thermal, and dielectric properties. The temperature evolution of the X-ray pair distribution functions of hybrid perovskites ABX(3) [A(+) = CH(3)NH(3) (MA) or CH(NH(2))(2) (FA); B(2+) = Sn or Pb; X(–) = Br, or I] in their cubic phases above 300 K reveals temperature-activated displacement (off-centering) of the divalent group 14 cations from their nominal, centered sites. This symmetry-lowering distortion phenomenon, previously dubbed emphanisis in the context of compounds such as PbTe, is attributed to Sn(2+) and Pb(2+) lone pair stereochemistry. Of the materials studied here, the largest displacements from the center of the octahedral sites are found in tin iodides, a more moderate effect is found in lead bromides, and the weakest effect is seen in lead iodides. The A-site cation appears to play a role as well, with the larger FA resulting in greater off-centering for both Sn(2+) and Pb(2+). Dynamic off-centering, which is concealed within the framework of traditional Bragg crystallography, is proposed to play a key role in the remarkable defect-tolerant nature of transport in these semiconductors via its effect on the polarizability of the lattice. The results suggest a novel chemical design principle for future materials discovery. Royal Society of Chemistry 2017-08-01 2017-06-16 /pmc/articles/PMC5621007/ /pubmed/28989600 http://dx.doi.org/10.1039/c7sc01429e Text en This journal is © The Royal Society of Chemistry 2017 http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Chemistry Laurita, Geneva Fabini, Douglas H. Stoumpos, Constantinos C. Kanatzidis, Mercouri G. Seshadri, Ram Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites |
title | Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
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title_full | Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
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title_fullStr | Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
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title_full_unstemmed | Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
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title_short | Chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites
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title_sort | chemical tuning of dynamic cation off-centering in the cubic phases of hybrid tin and lead halide perovskites |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5621007/ https://www.ncbi.nlm.nih.gov/pubmed/28989600 http://dx.doi.org/10.1039/c7sc01429e |
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