Despite the technical difficulty of imaging s-GO and us-GO flakes with a high enough contrast, TEM appears as the best compromise among the three microscopic techniques when comparing the lateral dimensions of all three materials (Figure ). Using TEM, we were able to detect more flakes within a wide range of sizes. The magnification must however be carefully set up, as higher magnifications tend to bias the results by excluding the largest flakes within the population. This can explain why the size distribution of l-GO obtained with TEM displays slightly lower values compared to the one obtained with optical microscopy.