Xiao Qi, Ma Bo, Wang Shu-Yan, Li Xiang-Yang, Yan Feng, Wang Qiang, Zhang Hao-Li
State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, P. R. China.
Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science Department, Soochow University, Suzhou, 215123, P. R. China.
Small. 2023 Dec;19(49):e2303608. doi: 10.1002/smll.202303608. Epub 2023 Aug 16.
Topological insulators (TIs) are characterized by a full insulating gap in the bulk and gapless edge or surface states, which have attracted tremendous attention. 2D Bi (110), as a typical TI, is of particular interest due to its low symmetry structure and topologically protected and spin-momentum-locked Dirac surface states. However, the material's potential applications are hindered by difficulties in fabrication, due to its strong semi-metallic bonding and poor stability. In this study, a novel electrochemical intercalation method for the fabrication of ultrathin Bi (110) nanosheets with the highest yield ever reported is presented. These nanosheets are stabilized through cathodic exfoliation in a reductive environment and further modification with polymer ionic liquids. The versatility of these nanosheets is demonstrated by fabricating flexible acoustic sensors with ultrahigh sensitivity. These sensors can even detect sounds as quiet as 45 dB. Furthermore, these sensors are utilized for acoustic-to-electric energy conversion and information transfer. This work offers a promising approach for scalable fabrication and preservation of ultrathin 2D TI Bi (110) nanosheets and paves the way for their integration into smart devices.
拓扑绝缘体（TIs）的特征是体内存在完全绝缘能隙，而边缘或表面态无带隙，这引起了极大关注。二维Bi(110)作为典型的拓扑绝缘体，因其低对称结构以及拓扑保护且自旋动量锁定的狄拉克表面态而备受关注。然而，由于其强半金属键合和较差的稳定性，该材料在制造方面存在困难，阻碍了其潜在应用。在本研究中，提出了一种新颖的电化学插层方法，用于制备超薄Bi(110)纳米片，其产率为有史以来报道的最高值。这些纳米片通过在还原环境中进行阴极剥离并进一步用聚合物离子液体修饰来实现稳定化。通过制造具有超高灵敏度的柔性声学传感器，展示了这些纳米片的多功能性。这些传感器甚至能够检测低至45分贝的声音。此外，这些传感器还用于声电能量转换和信息传递。这项工作为可扩展制造和保存超薄二维拓扑绝缘体Bi(110)纳米片提供了一种有前景的方法，并为将其集成到智能设备中铺平了道路。
