Zhang Baowei, Altamura Davide, Caliandro Rocco, Giannini Cinzia, Peng Lucheng, De Trizio Luca, Manna Liberato
Nanochemistry Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy.
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso 31, 16146 Genova, Italy.
J Am Chem Soc. 2022 Mar 23;144(11):5059-5066. doi: 10.1021/jacs.1c13544. Epub 2022 Mar 8.
CsPbBr nanoclusters have been synthesized by several groups and mostly employed as single-source precursors for the synthesis of anisotropic perovskite nanostructures or perovskite-based heterostructures. Yet, a detailed characterization of such clusters is still lacking due to their high instability. In this work, we were able to stabilize CsPbBr nanoclusters by carefully selecting ad hoc ligands (benzoic acid together with oleylamine) to passivate their surface. The clusters have a narrow absorption peak at 400 nm, a band-edge emission peaked at 410 nm at room temperature, and their composition is identified as CsPbBr. Synchrotron X-ray pair distribution function measurements indicate that the clusters exhibit a disk-like shape with a thickness smaller than 2 nm and a diameter of 13 nm, and their crystal structure is a highly distorted orthorhombic CsPbBr. Based on small- and wide-angle X-ray scattering analyses, the clusters tend to form a two-dimensional (2D) hexagonal packing with a short-range order and a lamellar packing with a long-range order.
多个研究小组已合成出CsPbBr纳米团簇，并且大多将其用作合成各向异性钙钛矿纳米结构或钙钛矿基异质结构的单源前驱体。然而，由于其高度不稳定性，对这类团簇仍缺乏详细的表征。在这项工作中，我们通过精心选择特定的配体（苯甲酸与油胺）来钝化其表面，从而能够稳定CsPbBr纳米团簇。这些团簇在400nm处有一个窄吸收峰，在室温下带边发射峰位于410nm处，并且它们的组成被确定为CsPbBr。同步加速器X射线对分布函数测量表明，这些团簇呈现出盘状形状，厚度小于2nm，直径为13nm，并且它们的晶体结构是高度扭曲的正交晶系CsPbBr。基于小角和广角X射线散射分析，这些团簇倾向于形成具有短程有序的二维（2D）六方堆积和具有长程有序的层状堆积。
