Synthesis and Assembly of Zinc Oxide Microcrystals by a Low‐Temperature Dissolution–Reprecipitation Process: Lessons Learned About Twin Formation in Heterogeneous Reactions
Synthesis and Assembly of Zinc Oxide Microcrystals by a Low‐Temperature Dissolution–Reprecipitation Process: Lessons Learned About Twin Formation in Heterogeneous Reactions
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DOI：
10.1002/chem.201904638
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发表时间：
2020-01
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影响因子：
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通讯作者：
R. Hoffmann;Maximilian Trapp;E. Erdem;M. Kratzer;C. Teichert;H. Kleebe;J. J. Schneider-J.
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文献类型：
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作者：
R. Hoffmann;Maximilian Trapp;E. Erdem;M. Kratzer;C. Teichert;H. Kleebe;J. J. Schneider-J.
摘要：采用醋酸锌、醋酸钴和六亚甲基四胺（HMTA）在乙醇和水的混合物中热水解的方法合成了六方片状掺杂钴的氧化锌单晶。矿化通过低温溶解-再沉淀过程从液相进行，形成碱式钴锌盐作为中间体。仔细选择溶剂混合物和掺杂量会影响晶体形状和氧化相的孪晶形成。对反应过程的理解是通过综合运用分析技术（即SEM， XRD， IR）实现的，包括对不同反应阶段的沉淀物进行深入的HRTEM研究。此外，EPR和紫外/可见光谱测量提供了关于钴掺杂剂插入锌矿晶格的信息。Langmuir-Blodgett （LB）技术被证明适用于在聚电解质多层功能化的玻璃基板上沉积血小板涂层，因此可用于形成含有有序镶嵌结构域的单层。在阴离子或阳离子表面改性的衬底上的沉积物之间没有发现主要差异。通过压电响应力显微镜（PFM）和开尔文探针力显微镜（KPFM）研究，对衬底的粘附性足以确定沉积的极性单晶的绝对取向。
Abstract Cobalt‐doped zinc oxide single crystals with the shape of hexagonal platelets were synthesized by thermohydrolysis of zinc acetate, cobalt acetate, and hexamethylenetetramine (HMTA) in mixtures of ethanol and water. The mineralization proceeds by a low‐temperature dissolution–reprecipitation process from the liquid phase by the formation of basic cobalt zinc salts as intermediates. The crystal shape as well as twin formation of the resulting oxide phase can be influenced by careful choice of the solvent mixture and the amount of doping. An understanding of the course of the reaction was achieved by comprehensive employment of analytical techniques (i.e., SEM, XRD, IR) including an in‐depth HRTEM study of precipitates from various reaction stages. In addition, EPR as well as UV/Vis spectroscopic measurements provide information about the insertion of the cobalt dopant into the zincite lattice. The Langmuir–Blodgett (LB) technique is shown to be suitable for depositing coatings of the platelets on glass substrates functionalized with polyelectrolyte multilayers and hence is applied for the formation of monolayers containing domains with ordered tessellation. No major differences are found between deposits on substrates with anionic or cationic surface modification. The adherence to the substrates is sufficient to determine the absolute orientation of the deposited polar single crystals by piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM) studies.