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 $\mathrm{F}{\mathrm{A}}_{0.9}\mathrm{M}{\mathrm{A}}_{0.1}\mathrm{Pb}{\mathrm{I}}_{2.23}{\mathrm{Br}}_{0.77}$. The hexagonal crystallographic structure with $P{6}_3$/mmc space group has been confirmed by transmission electron microscope study. Through a detailed analysis of the single crystal XRD data, the locations of $\mathrm{F}{\mathrm{A}}^{+}$ and $\mathrm{M}{\mathrm{A}}^{+}$ in the unit cell have been identified, and the off-centering of ${\mathrm{Pb}}^{2+}$ 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 $E_g$ = 2.27 eV and demonstrates photoluminescence activity. The thermal conductivity is disorder-dominated with an extremely low value of $0.17\mathrm{W}{\mathrm{m}}^{-1}{\mathrm{K}}^{-1}$ from about 75 K up to 325 K. The present investigation on $\mathrm{F}{\mathrm{A}}_{0.9}\mathrm{M}{\mathrm{A}}_{0.1}\mathrm{Pb}{\mathrm{I}}_{2.23}{\mathrm{Br}}_{0.77}$ 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.

中文翻译：

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4H铅基六方杂化钙钛矿单晶的结构、光学和电子特性

使用反溶剂蒸汽辅助结晶法生长了卤化铅杂化钙钛矿单晶。利用核磁共振和单晶 X 射线衍射建立了晶体的化学成分和结构模型，得出以下公式$\mathrm{F}{\mathrm{A}}_{0.9}\mathrm{中号}{\mathrm{A}}_{0.1}铅{\mathrm{我}}_{2.23}{溴}_{0.77}$。六方晶体结构$磷6_3$/ mmc空间群已被透射电子显微镜研究证实。通过对单晶 XRD 数据的详细分析，$\mathrm{F}{\mathrm{A}}^{+}$和$\mathrm{中号}{\mathrm{A}}^{+}$已经确定了单位晶胞中的偏心${铅}^{2+}$八面体位点上的问题已经被揭开，可能是由于孤对电子的泡利排斥。该材料是一种宽禁带半导体${乙}_G$= 2.27 eV 并表现出光致发光活性。热导率是无序主导的，具有极低的值$0.17\mathrm{瓦}{\mathrm{米}}^{-1}{\mathrm{K}}^{-1}$从大约 75 K 到 325 K。目前的调查$\mathrm{F}{\mathrm{A}}_{0.9}\mathrm{中号}{\mathrm{A}}_{0.1}铅{\mathrm{我}}_{2.23}{溴}_{0.77}$单晶表明，这种具有混合阳离子和阴离子无序的六方杂化卤化物钙钛矿家族获得了低热导率值。