Department of Engineering Science and Mechanics, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Department of Mechanical Engineering, University of Hong Kong , Pokfulam, Hong Kong.
ACS Appl Mater Interfaces. 2017 Nov 8;9(44):39059-39068. doi: 10.1021/acsami.7b13107. Epub 2017 Oct 26.
In this paper we provide insight into an anomalous corrosion process, referred to as electroablation (EA), which converts multilayer flakes of transition metal diselenides like MoSe into their corresponding monolayers when micromechanically exfoliated on a conductive electrode and subsequently subjected to a high anodic potential inside a conventional electrochemical cell. Photoluminescence intensity maps and scanning transmission electron microscopy (STEM) images confirmed the single crystalline nature and 2H-hexagonal lattice structure of the remnant monolayer MoSe flakes, indicating the superior corrosion stability of the monolayers compared to that of the bulk counterpart. It is noted that the EA technique is a low-cost alternative for high-yield synthesis of single crystalline monolayer MoSe at room temperature. We also found that the dynamics of such an electro-oxidation-mediated and self-limiting corrosion process differs significantly for MoSe and WSe. While we were able to engineer the corrosion conditions for the EA process to obtain monolayers of MoSe, our attempts to obtain monolayers of WSe were largely unsuccessful. Finally, we constructed a phenomenological physical chemistry framework to explain such anomalous corrosion processes in transition metal diselenides.
在本文中，我们深入研究了一种异常的腐蚀过程，称为电蚀（EA）。当在导电电极上进行微机械剥离并随后在传统电化学电池中施加高阳极电势时，多层过渡金属二硒化物（如 MoSe）薄片会转化为其相应的单层。光致发光强度映射和扫描透射电子显微镜（STEM）图像证实了残余单层 MoSe 薄片的单晶性质和 2H-六方晶格结构，表明与体相比，单层具有更高的腐蚀稳定性。需要注意的是，EA 技术是在室温下高产合成单晶单层 MoSe 的低成本替代方法。我们还发现，这种电氧化介导和自限制腐蚀过程的动力学对于 MoSe 和 WSe 有很大的不同。虽然我们能够对 EA 工艺的腐蚀条件进行工程设计以获得 MoSe 的单层，但我们获得 WSe 单层的尝试却大多失败了。最后，我们构建了一个唯象物理化学框架来解释过渡金属二硒化物中的这种异常腐蚀过程。
