Li Yun-Qin, Wang Xin-Yu, Zhu Shi-Yu, Tang Dai-Song, He Qi-Wen, Wang Xiao-Chun
Institute of Atomic and Molecular Physics, Jilin University, Changchun130012, China.
J Phys Chem Lett. 2022 Oct 20;13(41):9654-9663. doi: 10.1021/acs.jpclett.2c02660. Epub 2022 Oct 10.
Development of piezoelectric materials is limited partly due to the incompleteness of internal mechanism and the lack of vertical piezoelectricity. Herein, we theoretically identify the stable MoTO (T = S, Se, or Te) monolayers and bilayers. When two elements are given but another element can be changed, the larger the electronegativity difference ratio is, the stronger the piezoelectricity will be. Vertical piezoelectric coefficient of the MoTeO bilayer reaches 38.907 pm/V, which is 12 times larger than that of the bulk GaN. The "active asymmetric electron-transfer" strategy mainly contributes to the spontaneous remarkable piezoelectricity of MoTO. Importantly, we proposed the new method for calculating the piezoelectric coefficients of two-dimensional (2D) materials, which corresponds to the fact that 2D materials have a certain thickness. This study not only provides novel extraordinary candidates for energy conversion and touch-sensor nanodevices but also promotes a deeper understanding of piezoelectricity of 2D materials.
压电材料的发展受到一定限制，部分原因是其内部机制不完善以及缺乏垂直压电性。在此，我们从理论上确定了稳定的MoTO（T = S、Se或Te）单层和双层结构。当给定两种元素而另一种元素可以改变时，电负性差比越大，压电性越强。MoTeO双层的垂直压电系数达到38.907 pm/V，比块状GaN的垂直压电系数大12倍。“活性不对称电子转移”策略是MoTO具有显著自发压电性的主要原因。重要的是，我们提出了一种计算二维（2D）材料压电系数的新方法，这与二维材料具有一定厚度这一事实相对应。本研究不仅为能量转换和触摸传感器纳米器件提供了新型优异候选材料，还促进了对二维材料压电性的更深入理解。
