Yang Dandan, Wang Yan, Li Lijie, Yao Minggang, Zhang Wenxiong, Gu Hongxi, Zhang Sheng, Fan Mingjin, Sewvandi Galhenage Asha, Hu Dengwei
Faculty of Chemistry and Chemical Engineering, Engineering Research Center of Advanced Ferroelectric Functional Materials, Key Laboratory of Phytochemistry of Shaanxi Province, Baoji University of Arts and Sciences, 1 Hi-Tech Avenue, Baoji, Shaanxi 721013, P. R. China.
Institute for Solid State Physics, The University of Tokyo, Koto, Sayo, Hyogo 679-5148, Japan.
Inorg Chem. 2021 Jan 4;60(1):97-107. doi: 10.1021/acs.inorgchem.0c02409. Epub 2020 Dec 14.
KNbO (KN) piezoelectric polycrystals were prepared by a two-step solvothermal reaction process with the managed organic solvents as reaction mediums at a low temperature for a short time. In the solvothermal reaction system, the formation mechanism of polycrystalline KN is mainly the dissolution-deposition mechanism. The influences of alkalinity, viscosity, and the polarity for reaction mediums on the formation of the niobates were investigated. The chemical reaction mechanisms of niobate products and formation mechanism of niobate crystals from the precursor were clarified. The regulating and controlling mechanism of the phase compositions, the morphologies, and the lattice constants for the niobates obtained in varied reaction mediums were revealed. The obtained KN piezoelectric polycrystals are constructed from oriented KN nanocrystals. Piezoelectric hysteresis loops of cuboid KN polycrystals were detected for the first time. A prepared cuboid KN polycrystal shows an average * value of 32 pm/V. The study provides a strategy for the development of oriented KN piezoelectric materials to apply the orientation engineering.
铌酸钾钠（KN）压电多晶体是通过两步溶剂热反应过程制备的，该过程以可控的有机溶剂作为反应介质，在低温下短时间内进行。在溶剂热反应体系中，多晶KN的形成机制主要是溶解-沉积机制。研究了反应介质的碱度、粘度和极性对铌酸盐形成的影响。阐明了铌酸盐产物的化学反应机制以及前驱体形成铌酸盐晶体的机制。揭示了在不同反应介质中获得的铌酸盐的相组成、形貌和晶格常数的调控机制。所获得的KN压电多晶体由取向的KN纳米晶体构成。首次检测到长方体KN多晶体的压电滞回环。制备的长方体KN多晶体的平均*值为32 pm/V。该研究为开发取向KN压电材料以应用取向工程提供了一种策略。
