Xu Xiang, Chen Yunxin, Liu Pengbin, Luo Hao, Li Zexin, Li Dongyan, Wang Haoyun, Song Xingyu, Wu Jinsong, Zhou Xing, Zhai Tianyou
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China.
Nanostructure Research Center, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P. R. China.
Nat Commun. 2024 May 22;15(1):4368. doi: 10.1038/s41467-024-48690-7.
Two-dimensional (2D) AMX compounds are a family of mixed ionic and electronic conductors (where A is a monovalent metal ion, M is a trivalent metal, and X is a chalcogen) that offer a fascinating platform to explore intrinsic coupled ionic-electronic properties. However, the synthesis of 2D AMX compounds remains challenging due to their multielement characteristics and various by-products. Here, we report a separated-precursor-supply chemical vapor deposition strategy to manipulate the chemical reactions and evaporation of precursors, facilitating the successful fabrication of 20 types of 2D AMX flakes. Notably, a 10.4 nm-thick AgCrS flake shows superionic behavior at room temperature, with an ionic conductivity of 192.8 mS/cm. Room temperature ferroelectricity and reconfigurable positive/negative photovoltaic currents have been observed in CuScS flakes. This study not only provides an effective approach for the synthesis of multielement 2D materials with unique properties, but also lays the foundation for the exploration of 2D AMX compounds in electronic, optoelectronic, and neuromorphic devices.
二维（2D）AMX化合物是一类混合离子导体和电子导体（其中A是一价金属离子，M是三价金属，X是硫族元素），为探索本征离子 - 电子耦合特性提供了一个引人入胜的平台。然而，由于其多元素特性和各种副产物，二维AMX化合物的合成仍然具有挑战性。在此，我们报告了一种分离前驱体供应的化学气相沉积策略，以控制前驱体的化学反应和蒸发，从而成功制备了20种二维AMX薄片。值得注意的是，一个10.4纳米厚的AgCrS薄片在室温下表现出超离子行为，离子电导率为192.8 mS/cm。在CuScS薄片中观察到了室温铁电性和可重构的正/负光伏电流。这项研究不仅为合成具有独特性质的多元素二维材料提供了一种有效方法，也为在电子、光电子和神经形态器件中探索二维AMX化合物奠定了基础。
