Ion adsorption-induced reversible polarization switching of a van der Waals layered ferroelectric

• Published in: Nature communications Vol. 12; no. 1; p. 655
• Main Authors: Xu, Dong-Dong, Ma, Ru-Ru, Fu, Ai-Ping, Guan, Zhao, Zhong, Ni, Peng, Hui, Xiang, Ping-Hua, Duan, Chun-Gang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28-01-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 147/3; 639/301/357/1018; 639/766/119/996; Adsorption; Ammonium; Anions; Cations; Dipoles; Electrical resistivity; Energy consumption; Energy storage; Ferroelectric materials; Ferroelectricity; First principles; Functional materials; Humanities and Social Sciences; Interfaces; Ion adsorption; Liquid-solid interfaces; multidisciplinary; Physical properties; Polarization; Retention time; Room temperature; Science; Science (multidisciplinary); Structural damage; Switching
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-20945-7

Solid-liquid interface is a key concept of many research fields, enabling numerous physical phenomena and practical applications. For example, electrode-electrolyte interfaces with electric double layers have been widely used in energy storage and regulating physical properties of functional materials. Creating a specific interface allows emergent functionalities and effects. Here, we show the artificial control of ferroelectric-liquid interfacial structures to switch polarization states reversibly in a van der Waals layered ferroelectric CuInP
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(CIPS). We discover that upward and downward polarization states can be induced by spontaneous physical adsorption of dodecylbenzenesulphonate anions and N,N-diethyl-N-methyl-N-(2-methoxyethyl)-ammonium cations, respectively, at the ferroelectric-liquid interface. This distinctive approach circumvents the structural damage of CIPS caused by Cu-ion conductivity during electrical switching process. Moreover, the polarized state features super-long retention time (>1 year). The interplay between ferroelectric dipoles and adsorbed organic ions has been studied systematically by comparative experiments and first-principles calculations. Such ion adsorption-induced reversible polarization switching in a van der Waals ferroelectric enriches the functionalities of solid-liquid interfaces, offering opportunities for liquid-controlled two-dimensional ferroelectric-based devices.
Whether it is possible to achieve polarization inversion in a ferroelectric without any energy consumption is an open question. Here, the authors demonstrate an energy-free approach to control the polarization state of CuInP
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, a typical room-temperature van der Waals layered ferroelectric.