Imperial College London
Alternate

DrJessicaWade

Faculty of Engineering, Department of Materials

Lecturer in Functional Materials
 
 
 
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Contact

 

jessica.wade

 
 
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Location

 

B336Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Karim:2019:10.1021/acs.chemmater.9b03267,
author = {Karim, MMS and Ganose, AM and Pieters, L and Leung, WWW and Wade, J and Zhang, L and Scanlon, DO and Palgrave, RG},
doi = {10.1021/acs.chemmater.9b03267},
journal = {Chemistry of Materials},
pages = {9430--9444},
title = {Anion distribution, structural distortion, and symmetry-driven optical band gap bowing in mixed halide Cs2SnX6 vacancy ordered double perovskites},
url = {http://dx.doi.org/10.1021/acs.chemmater.9b03267},
volume = {31},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Mixed anion compounds in the Fm3m vacancy ordered perovskite structure were synthesized and characterized experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br, and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series with no evidence of long-range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6 but proved highly nonlinear with changes in composition. In mixed halide compounds, it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this was attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterized by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide–bromide compounds, where the larger iodide anions preferentially adopted trans configurations.
AU  - Karim,MMS
AU  - Ganose,AM
AU  - Pieters,L
AU  - Leung,WWW
AU  - Wade,J
AU  - Zhang,L
AU  - Scanlon,DO
AU  - Palgrave,RG
DO  - 10.1021/acs.chemmater.9b03267
EP  - 9444
PY  - 2019///
SN  - 0897-4756
SP  - 9430
TI  - Anion distribution, structural distortion, and symmetry-driven optical band gap bowing in mixed halide Cs2SnX6 vacancy ordered double perovskites
T2  - Chemistry of Materials
UR  - http://dx.doi.org/10.1021/acs.chemmater.9b03267
UR  - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000500039100023&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://pubs.acs.org/doi/10.1021/acs.chemmater.9b03267
UR  - http://hdl.handle.net/10044/1/99173
VL  - 31
ER  -
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