Abstract
Lead halide hybrid perovskite single crystals have been grown using antisolvent vapor-assisted crystallization. The chemical composition and structural model of the crystals have been established using nuclear magnetic resonance and single crystal x-ray diffraction, leading to the formula . The hexagonal crystallographic structure with /mmc space group has been confirmed by transmission electron microscope study. Through a detailed analysis of the single crystal XRD data, the locations of and in the unit cell have been identified, and the off-centering of on the octahedral sites has been unveiled, probably due to the Pauli repulsion of the lone pair. This material is a wide-gap semiconductor with = 2.27 eV and demonstrates photoluminescence activity. The thermal conductivity is disorder-dominated with an extremely low value of from about 75 K up to 325 K. The present investigation on single crystal demonstrates that low values of thermal conductivities are obtained in this hexagonal family of hybrid halide perovskites, with mixed cationic and anionic disorder.
- Received 4 July 2023
- Revised 18 October 2023
- Accepted 25 January 2024
DOI:https://doi.org/10.1103/PhysRevMaterials.8.025403
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