A practical characterisation protocol for liquid-phase synthesised heterogeneous graphene

We demonstrate a characterisation protocol for quantifying nanostructural features associated with heterogeneous graphene nanosheets, including the lateral dimension, thickness and defect density of flakes produced by liquid phase exfoliation methods. The underlying basis for the protocol is a cross correlation between high resolution electron probe-based techniques and lower resolution but higher throughput photon probe-based characterisation methods. Using statistical data analysis we are able to develop a practical characterisation protocol that provides access to the precision and accuracy of the various graphene characterisation techniques. We have shown that the lateral dimension and thickness of heterogeneous graphene flakes can be rapidly quantified via optical mapping techniques. The defect densities within graphene samples can be accessed via Raman micro-spectroscopy. Based on the high throughput photon probe-based characterisation method, statistically representative data for heterogeneous graphene nanosheets can be obtained. Such information can be used to differentiate between inhomogeneous graphene samples in large length scales and thus can be useful for optimising graphene synthesis processes. (C) 2020 Elsevier Ltd. All rights reserved.