No particles were visible under the optical microscope in the case of s-GO and us-GO (Figure ), confirming the production of materials smaller than the optical microscopy diffraction limit (Abbe's law). In contrast, in the l-GO sample, particles with lateral dimensions above 1 µm were clearly visible (Table , Supporting Information). TEM micrographs showed a clear difference in lateral dimensions among the three materials (Figure ). This was proven to be statistically significant (p < 0.001) after performing the Wilcoxon rank sum test (Figure ), as the lateral dimensions of l-GO were an order of magnitude greater than the lateral dimensions of s-GO. The lateral dimensions of us-GO were approximately 5 times inferior than those of s-GO, reflecting a clear reduction in size compared to l-GO. Accordingly, the statistical analysis of the AFM scan dataset uncovered a clear statistical difference between l-GO and the other two sample groups (p < 0.001). However, while the images reflect a clear difference in lateral dimensions among the three GO types (Figure ), this was not statistically significant between s-GO and us-GO (Figure ). Nonetheless, the size distribution was narrower for us-GO, which contained flakes with lateral dimensions below 340 nm, compared to s-GO, which was characterised by flakes with lateral dimensions below 740 nm. This was also reflected in Figure , where the population of larger flakes that were identified as outliers was more pronounced in us-GO. The flake thickness for all three materials was also measured using AFM height scans. Typical cross section of l-GO samples and thickness boxplot distributions are shown in Figure . The majority of the measured GO flakes in all three types had a thickness between 1 and 4 nm (Figure ), which defined them as single-to few-layer GO materials according to referential nomenclature .