Elucidation of an intrinsic parameter for evaluating the electrical quality of powder-type graphene materials

다국어 초록 (Multilingual Abstract)

A test method for evaluating the quality of powder-type graphene products, such as reduced graphene oxide and graphene flakes, was developed. The pelletizer was selected for a sampling tool, which enables us to formulate the product as a measurable sample. Various parameters were measured from the pelletized sample in order to elucidate the best parameter for representing the quality of the graphene products in terms of their electrical properties. Based on the analysis of 4-probe measurement data on the pelletized sample, the best intrinsic parameter is volume resistivity (or volume conductivity) rather than resistivity (or conductivity). Additionally, the possible modification of a sample before and after the pressurization was investigated by electron microscopy and Raman spectroscopy. No significant modification was observed. The volume conductivity in the two types of the graphene was different from their individual conductivities by one order of magnitude. Based on the results of X-ray photoelectron spectroscopy and Raman spectroscopy measurements, the volume conductivity of the graphene samples was governed by the oxygen content in the sample. Our achievements will promote the effective use of powder-type graphene materials for further applications.