The sonication step employed in the present work was shown to effectively decrease the lateral dimensions of GO flakes (Figure ). The lateral dimensions of l-GO flakes could be easily assessed using optical microscopy due to their micrometric scale (Figure ), whereas the analysis of the lateral dimensions of s-GO and us-GO flakes required both TEM (Figure ) and AFM (Figure ). The lateral dimensions of GO flakes are characterised by a log-normal distribution that not only spans multiple orders of magnitude, but also has a pronounced skewness . Instead of conventionally plotting this distribution as a histogram, the boxplot representation can remove the interpretation bias caused by a small number of larger flakes, which can be assumed as outliers.