Thanks to their excellent thermal and optical properties, graphene oxide quantum dots (GOQD) have been extensively explored for several applications, such as composite material, optoelectronic devices, solar cells, and fluorescence materials, among others. Consequently, GOQDs are commercially available suspended in a solution. However, the density, size, and crystallinity of commercially available GOQDs can differ a lot from one manufacturer to another, which rarely provide exhaustive information about them. Furthermore, a recent report has questioned the quality of graphene‐based materials produced by liquid phase exfoliation. Here a statistical analysis of the quality of commercially available GOQDs, using transmission electron microscope (TEM), is presented. This technique enables to observe the internal structure, thickness, lattice structure, orientation, and local defects of the samples at atomic scale. High resolution TEM images reveal that the thickness of the GOQDs is not homogenous from center to edges within one single domain. The edges show hexagonal lattice (monolayer) while the central location shows to be rhomboidal structure (multilayer). This work provides clear statistical information about the quality of the commercially available GOQDs.

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基于透射电子显微镜的市售氧化石墨烯量子点的统计分析

归因于其优异的热和光学性能，氧化石墨烯量子点（GOQD）已在多种应用中进行了广泛探索，例如复合材料，光电器件，太阳能电池和荧光材料等。因此，GOQD可以悬浮在溶液中商购。但是，市售GOQD的密度，尺寸和结晶度在一个制造商与另一制造商之间可能相差很大，因此很少提供有关它们的详尽信息。此外，最近的一份报告质疑液相剥离产生的石墨烯基材料的质量。这里介绍了使用透射电子显微镜（TEM）对市售GOQD的质量进行的统计分析。该技术可以观察内部结构，厚度，晶格结构，取向和样品在原子尺度上的局部缺陷。高分辨率TEM图像显示GOQD的厚度在一个域内从中心到边缘不均匀。边缘显示为六边形格子（单层），而中心位置显示为菱形结构（多层）。这项工作提供了有关市售GOQD质量的清晰统计信息。