Liu Guoliang
School of Information Technology, Jiangsu Open University, Nanjing, 210017, China.
Sci Rep. 2025 Jan 3;15(1):613. doi: 10.1038/s41598-024-84898-9.
Because of its dimensional characteristics, two-dimensional (2D) materials exhibit many special properties. The key to researching their features is to prepare high-quality larger-area monolayer 2D materials. Metal-assisted mechanical exfoliation method offers the possibility. However, there is still an unclear mechanism. We take transition metal dichalcogenides (TMD) as examples to perform serials of first-principles calculations to study their interlayer interaction. The calculated results demonstrate that the main factors affecting the interlayer interaction of 2D TMD materials include their structural features and the elemental features. The smaller interlayer distance between the topmost two layers than that of bulk leads to the stronger interlayer bonding energy, which results in the difficulty to exfoliate the large-area monolayer 2D crystals successfully. Further, we selected Ti, Cr and Au as the assisted metal due to their enhanced density of states near the Fermi level to calculate the adhesion energies of TMD on their surfaces. We found that there exists strong adhesion energy between 2D crystal and metal, which stretches the spacing of the topmost two layers and leads to the electron density rearrangement. Therefore, metal assisted mechanical exfoliation facilitates the successful preparation of monolayer 2D crystal.
由于其尺寸特性，二维（2D）材料展现出许多特殊性质。研究其特性的关键在于制备高质量的大面积单层二维材料。金属辅助机械剥离法提供了这种可能性。然而，其机制仍不明确。我们以过渡金属二硫属化物（TMD）为例进行了一系列第一性原理计算，以研究它们的层间相互作用。计算结果表明，影响二维TMD材料层间相互作用的主要因素包括其结构特征和元素特征。最顶层两层之间的层间距比体材料的小，导致层间结合能更强，这使得成功剥离大面积单层二维晶体变得困难。此外，由于Ti、Cr和Au在费米能级附近的态密度增强，我们选择它们作为辅助金属来计算TMD在其表面上的粘附能.我们发现二维晶体与金属之间存在很强的粘附能，这使得最顶层两层的间距增大并导致电子密度重新分布.因此，金属辅助机械剥离有助于单层二维晶体的成功制备。
