Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6
<p>Vacancy-ordered double perovskites A<small><sub>2</sub></small>BX<small><sub>6</sub></small> are attracting attention due to the isolated octahedra making them an ideal playground for studying perovskite structure-property relationshi...
| Päätekijät: | , , , , , , |
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| Aineistotyyppi: | Journal article |
| Kieli: | English |
| Julkaistu: |
Royal Society of Chemistry
2022
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| _version_ | 1826309827017572352 |
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| author | Liu, Y Cockcroft, JK Chen, Z Hayward, MA Henry, PF Perry, RS Palgrave, RG |
| author_facet | Liu, Y Cockcroft, JK Chen, Z Hayward, MA Henry, PF Perry, RS Palgrave, RG |
| author_sort | Liu, Y |
| collection | OXFORD |
| description | <p>Vacancy-ordered double perovskites A<small><sub>2</sub></small>BX<small><sub>6</sub></small> are attracting attention due to the isolated octahedra making them an ideal playground for studying perovskite structure-property relationships. MA<small><sub>2</sub></small>TeCl<small><sub>6</sub></small> single crystals have been successfully grown from solution. X-ray structure experiments as a function of temperature have demonstrated two structural phase transitions: from cubic <em>Fm3̄</em><em>m</em> (high temperature, phase I) to trigonal <em>P3̄</em><em>m</em>1 (intermediate temperature, phase II) at 460 K and then to trigonal <em>P3̄</em>1<em>c</em> (low temperature, phase III) at 200 K. Intriguingly, we observe a negative thermal expansion for the <em>c</em>-axis in phase II believed to caused by dynamic tilting of the C–N bond in the MA<small><sup>+</sup></small> ion. We have modified and extended the calculation of the Brown radii ratio in the perovskites to include hybrid A<small><sub>2</sub></small>BX<small><sub>6</sub></small> compounds by selecting the shortest A–X distance for the ratio equation. We find that for ratios between 0.89 and 1.17, typically the <em>Fm3̄</em><em>m</em> cubic structure is observed, while for ratios above 1.17, mostly distorted structures are found.</p> |
| first_indexed | 2024-03-07T07:41:31Z |
| format | Journal article |
| id | oxford-uuid:d27f0803-04e7-4ead-817e-c34c81c9de27 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:41:31Z |
| publishDate | 2022 |
| publisher | Royal Society of Chemistry |
| record_format | dspace |
| spelling | oxford-uuid:d27f0803-04e7-4ead-817e-c34c81c9de272023-04-21T13:18:54ZPhase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d27f0803-04e7-4ead-817e-c34c81c9de27EnglishSymplectic ElementsRoyal Society of Chemistry2022Liu, YCockcroft, JKChen, ZHayward, MAHenry, PFPerry, RSPalgrave, RG<p>Vacancy-ordered double perovskites A<small><sub>2</sub></small>BX<small><sub>6</sub></small> are attracting attention due to the isolated octahedra making them an ideal playground for studying perovskite structure-property relationships. MA<small><sub>2</sub></small>TeCl<small><sub>6</sub></small> single crystals have been successfully grown from solution. X-ray structure experiments as a function of temperature have demonstrated two structural phase transitions: from cubic <em>Fm3̄</em><em>m</em> (high temperature, phase I) to trigonal <em>P3̄</em><em>m</em>1 (intermediate temperature, phase II) at 460 K and then to trigonal <em>P3̄</em>1<em>c</em> (low temperature, phase III) at 200 K. Intriguingly, we observe a negative thermal expansion for the <em>c</em>-axis in phase II believed to caused by dynamic tilting of the C–N bond in the MA<small><sup>+</sup></small> ion. We have modified and extended the calculation of the Brown radii ratio in the perovskites to include hybrid A<small><sub>2</sub></small>BX<small><sub>6</sub></small> compounds by selecting the shortest A–X distance for the ratio equation. We find that for ratios between 0.89 and 1.17, typically the <em>Fm3̄</em><em>m</em> cubic structure is observed, while for ratios above 1.17, mostly distorted structures are found.</p> |
| spellingShingle | Liu, Y Cockcroft, JK Chen, Z Hayward, MA Henry, PF Perry, RS Palgrave, RG Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title | Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title_full | Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title_fullStr | Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title_full_unstemmed | Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title_short | Phase transitions and optical properties of the trigonal perovskite (CH3NH3)2TeCl6 |
| title_sort | phase transitions and optical properties of the trigonal perovskite ch3nh3 2tecl6 |
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