Abstract Molybdenum disulfide quantum dots (MQDs) possess unique optical and electronic properties owing to their typical microstructures, such as two-dimensional (2D) honeycomb structure, quantum confinement, and surface passivation. However, the microstructures that have been experimentally investigated are far from being sufficient evidence for clearly understanding the electronic and optical mechanism due to the lack of effective detection methods. Here, pure MQDs were fabricated through the laser ablation of bulk MoS2 along the orientation parallel to the MoS2 layers, which is essential for surface-enhanced Raman scattering (SERS) measurement. Surface-enhanced resonance Raman scattering (SERRS) is introduced to dramatically enhance the Raman signals of MQDs by coating Ag@MQDs on a silver electrode with nanoscale roughness and highlights much more abundant Raman peaks corresponding to the MQD microstructures of the hexagonal crystalline domains, passivation electron-donating groups, defects, and disorders than those highlighted by normal Raman scattering (NRS) and resonant Raman scattering (RRS). Furthermore, owing to the adsorption of MQDs via oxygen-containing passivation groups on the silver surface, SERRS highlights more vibrations associated with passivation structures than Fourier transform infrared (FTIR) spectra that are usually applied to provide crucial evidence for the existence of passivation groups. Abundant Raman peaks derived from the defects and disorders of MQDs are also observed. Additionally, several second-order Raman peaks that are related to the hexagonal structure of MQDs can also be observed and are induced by defects, disorders, and adsorption on the silver surface. This work indicates that SERRS has advantages over high-resolution transmission electron microscopy (HRTEM), FTIR, NRS and RRS in characterizing the microstructures of MQDs.

中文翻译：

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通过在具有纳米级粗糙度的银电极上涂覆 Ag@MQD 对 MoS2 量子点进行表面增强共振拉曼散射

摘要 二硫化钼量子点 (MQD) 由于其典型的微结构，如二维 (2D) 蜂窝结构、量子限制和表面钝化而具有独特的光学和电子特性。然而，由于缺乏有效的检测方法，已经通过实验研究的微观结构远不能成为清楚理解电子和光学机制的充分证据。在这里，通过沿着平行于 MoS2 层的方向对块体 MoS2 进行激光烧蚀来制造纯 MQD，这对于表面增强拉曼散射 (SERS) 测量至关重要。引入表面增强共振拉曼散射 (SERRS) 以通过在具有纳米级粗糙度的银电极上涂覆 Ag@MQD 来显着增强 MQD 的拉曼信号，并突出显示与六方晶畴的 MQD 微结构相对应的更丰富的拉曼峰，钝化与正常拉曼散射 (NRS) 和共振拉曼散射 (RRS) 突出显示的那些相比，供电子基团、缺陷和紊乱。此外，由于 MQD 通过银表面上的含氧钝化基团吸附，与通常用于为钝化基团存在提供重要证据的傅立叶变换红外 (FTIR) 光谱相比，SERRS 突出了更多与钝化结构相关的振动。还观察到源自 MQD 的缺陷和紊乱的丰富拉曼峰。此外，还可以观察到几个与 MQD 六方结构相关的二阶拉曼峰，这些峰是由银表面的缺陷、无序和吸附引起的。这项工作表明 SERRS 在表征 MQD 的微观结构方面优于高分辨率透射电子显微镜 (HRTEM)、FTIR、NRS 和 RRS。