Weighting graphene with QCM to monitor interfacial mass changes

TL;DR

This paper presents a novel QCM-based method to measure the mass density of graphene and monitor interfacial mass changes during biomolecule adsorption and oxidation, providing high sensitivity and layer determination.

Contribution

The study introduces a transfer printing technique for large-area graphene on QCM and demonstrates its application in measuring mass density and interfacial mass variations.

Findings

Measured graphene mass density as ~118 ng/cm2

Extended technique to monitor biomolecule adsorption and oxidation

Enabled determination of graphene layer number

Abstract

In this Letter, using quartz crystal microbalance (QCM), we experimentally determined the mass density of graphene grown by chemical vapor deposition method. We developed a transfer printing technique to integrate large area single-layer graphene on QCM. By monitoring the resonant frequency of an oscillating quartz crystal loaded with graphene, we were able to measure the mass density of graphene as ~118 ng/cm2, which is significantly larger than the ideal graphene (~76 ng/cm2) mainly due to the presence of wrinkles and organic/inorganic residues on graphene sheets. High sensitivity of quartz crystal resonator allowed us to determine the number of graphene layers in samples. (The technique is very sensitive and able to determine the number of graphene layers in a particular sample.) Besides, we extended our technique to probe interfacial mass variation during adsorption of biomolecules on graphene surface, and plasma-assisted oxidation of graphene. (Besides, we extended our technique to probe interfacial mass variation during adsorption of biomolecules on graphene surface, and plasma-assisted oxidation of graphene.)