Abstract An effective multi-exfoliation method based on lithium (Li) intercalation has been demonstrated for preparing monolayer molybdenum disulfide (MoS 2 ) quantum dots (QDs). The cutting mechanism of MoS 2 QDs may involve the complete breakup around the defects and edges during the reaction of Li x MoS 2 with water and its following ultrasonication process. The multiply exfoliation make the MoS 2 fragile and easier to break up. After the third exfoliation, a large number of monolayer MoS 2 QDs is formed. The as-prepared MoS 2 QDs show photoluminescence (PL) inactive due to the existence of 1T phase. After heating treatment, the PL intensity excited at 300 nm is enhanced by five times. The MoS 2 QDs solution has an excitation-dependent luminescence emission which shifts to longer wavelengths when the excitation wavelength changes from 280 nm to 370 nm. The optical properties are explored based on the quantum confinement and edge effect.

中文翻译：

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基于锂嵌入的多重剥离产生的发光单层MoS 2 量子点

摘要 一种基于锂 (Li) 嵌入的有效多重剥离方法已被证明可用于制备单层二硫化钼 (MoS 2 ) 量子点 (QD)。MoS 2 量子点的切割机制可能涉及在Li x MoS 2 与水反应及其后续超声处理过程中缺陷和边缘周围的完全破碎。多次剥离使MoS 2 脆弱且更容易分解。第三次剥离后，形成大量单层MoS 2 QD。由于 1T 相的存在，所制备的 MoS 2 QD 显示光致发光 (PL) 不活跃。热处理后，在 300 nm 激发的 PL 强度增强了五倍。MoS 2 QDs 溶液具有激发相关的发光发射，当激发波长从 280 nm 变为 370 nm 时，它会转移到更长的波长。基于量子限制和边缘效应探索光学特性。