Sun Junhui, Cheng Ziwen, Huang Qing, He Heming, Francisco Joseph S, Du Shiyu
School of Mechanical Engineering, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China.
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
J Phys Chem Lett. 2022 Jul 21;13(28):6597-6603. doi: 10.1021/acs.jpclett.2c01403. Epub 2022 Jul 14.
On the basis of the intrinsic characteristics of the layered materials, here we report a universal principle for the production of intact monolayers via layer-by-layer exfoliation from their bulk via positive charge doping. At experimental accessible densities () of ∼10 cm, various multilayer crystals, including graphite, hexagonal boron nitride, transition metal dichalcogenides, MXenes, and black phosphorus, can be exfoliated into the corresponding monolayers through density functional theory stimulations. The carrier critical thresholds for exfoliating are found to be nearly independent of thickness but dependent on surface size. The universality of positive charge-driven exfoliation originates from the common intrinsic characteristics of electronic structures for layered materials. The positively doped charges that preferentially accumulate near the surface induce interlayer repulsion, leading to layer-by-layer exfoliation when repulsion surpasses interlayer van der Waals force. This strategy may open the possibility of producing diverse high-quality two-dimensional monolayers with a small number of defects toward large-scale manufacturing.
基于层状材料的固有特性，我们在此报告一种通用原理，即通过正电荷掺杂从其块体材料中逐层剥离来制备完整的单层材料。在实验可达到的密度（约为10厘米）下，通过密度泛函理论模拟，各种多层晶体，包括石墨、六方氮化硼、过渡金属二硫属化物、MXenes和黑磷，都可以被剥离成相应的单层材料。发现剥离的载流子临界阈值几乎与厚度无关，但与表面尺寸有关。正电荷驱动剥离的普遍性源于层状材料电子结构的共同固有特性。优先在表面附近积累的正掺杂电荷会引起层间排斥，当排斥力超过层间范德华力时，就会导致逐层剥离。这种策略可能为大规模制造具有少量缺陷的各种高质量二维单层材料开辟可能性。
