Halide Mixing and Phase Segregation in Cs2AgBiX6 (X=Cl, Br, I) Double Perovskites from Cesium-133 Solid-State NMR and Optical Spectroscopy
Authors
Saski, Marcin
Galkowski, Krzysztof
Lewiński, Janusz
Prochowicz, Daniel
Titman, Jeremy J
Publication Date
2020-10-13Journal Title
Chemistry of Materials
ISSN
0897-4756
Publisher
American Chemical Society (ACS)
Number
acs.chemmater.0c01255
Language
en
Type
Article
This Version
VoR
Metadata
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Kubicki, D., Saski, M., Macpherson, S., Galkowski, K., Lewiński, J., Prochowicz, D., Titman, J. J., & et al. (2020). Halide Mixing and Phase Segregation in Cs2AgBiX6 (X=Cl, Br, I) Double Perovskites from Cesium-133 Solid-State NMR and Optical Spectroscopy. Chemistry of Materials, (acs.chemmater.0c01255) https://doi.org/10.1021/acs.chemmater.0c01255
Abstract
All-inorganic double perovskites (elpasolites) are a promising potential alternative to lead halide perovskite in optoelectronic applications. While halide mixing is a well-established strategy for band gap tuning, little is known about halide mixing and phase segregation phenomena in double perovskites. Here, we synthesize a wide range of single− and mixed−halide Cs2AgBiX6 (X=Cl, Br, I) double perovskites using mechanosynthesis and probe their atomic-level microstructure using 133Cs solid-state MAS NMR. We show that mixed Cl/Br materials form pure phases for any Cl/Br ratio while Cl/I and Br/I mixing is only possible with-in a narrow range of halide ratios (<3 mol% I) and leads to a complex mixture of products for higher ratios. We characterize the optical properties of the resulting materials and show that halide mixing does not lead to an appreciable tunability of the PL emission. We find that iodide incorporation is particularly pernicious in that it quenches the PL emission intensity and radiative charge carrier lifetimes for iodide ratios as low as 0.3 mol%. Our study shows that sol-id-state NMR, in conjunction with optical spectroscopies, provides a comprehensive understanding of the structure-activity relationships, halide mixing and phase segregation phenomena in Cs2AgBiX6 (X=Cl, Br, I) double perovskites.
Sponsorship
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (841136)
Royal Society (UF150033)
European Research Council (756962)
Engineering and Physical Sciences Research Council (EP/R023980/1)
Embargo Lift Date
2100-01-01
Identifiers
External DOI: https://doi.org/10.1021/acs.chemmater.0c01255
This record's URL: https://www.repository.cam.ac.uk/handle/1810/310877
Rights
Attribution 4.0 International (CC BY)
Licence URL: http://creativecommons.org/licenses/by/4.0/
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