State Key Laboratory of Chemical Engineering, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, China.
Departments of Chemistry, Biochemistry and Molecular Biology, Physics, and Center for 2-Dimensional and Layered Materials, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
J Am Chem Soc. 2016 Apr 20;138(15):5143-9. doi: 10.1021/jacs.6b01502. Epub 2016 Apr 7.
The controlled exfoliation of transition metal dichalcogenides (TMDs) into pristine single- or few-layer nanosheets remains a significant barrier to fundamental studies and device applications of TMDs. Here we report a novel strategy for exfoliating crystalline MoS2 into suspensions of nanosheets with retention of the semiconducting 2H phase. The controlled reaction of MoS2 with substoichiometric amounts n-butyllithium results in intercalation of the edges of the crystals, which are then readily exfoliated in a 45 vol % ethanol-water solution. Surprisingly, the resulting colloidal suspension of nanosheets was found (by electron microscopy and atomic force microscopy) to consist mostly of trilayers. The efficiency of exfoliation of the pre-intercalated sample is increased by at least 1 order of magnitude relative to the starting MoS2 microcrystals, with a mass yield of the dispersed nanosheets of 11-15%.
过渡金属二硫属化物（TMDs）的可控剥离成原始的单层或少数层纳米片仍然是 TMDs 基础研究和器件应用的一个重大障碍。在这里，我们报告了一种将结晶 MoS2 剥离成具有保留半导体 2H 相的纳米片悬浮液的新策略。MoS2 与亚化学计量的正丁基锂的受控反应导致晶体边缘的插层，然后在 45vol%的乙醇-水溶液中很容易剥离。令人惊讶的是，通过电子显微镜和原子力显微镜发现，所得的胶体纳米片悬浮液主要由三层组成。与起始 MoS2 微晶体相比，预插层样品的剥离效率至少提高了 1 个数量级，分散纳米片的质量产率为 11-15%。
