Direction-sensitive graphene flow sensor

TL;DR

This paper introduces a graphene-based flow sensor that detects flow direction through an externally gated reference electrode, enhancing signal amplitude and enabling direction-sensitive measurements in aqueous solutions.

Contribution

It presents a novel graphene flow sensor design utilizing external gating and a reference electrode to achieve flow direction sensitivity and improved signal strength.

Findings

Enhanced flow-induced signal amplitude with external gating

Successful detection of flow direction in aqueous solutions

Analysis of Coulomb interactions at the graphene-solution interface

Abstract

Graphene flow sensors hold great prospects for applications, but also encounter many difficulties, such as unwanted electrochemical phenomena, low measurable signal and limited dependence on the flow direction. This study proposes a novel approach allowing for the detection of a flow direction-dependent electric signal in aqueous solutions of salts, acids and bases. The key element in the proposed solution is the use of a reference electrode which allows external gating of the graphene structure. Using external gating enables to enhance substantially the amplitude of the flow-generated signal. Simultaneous measurement of the reference electrode current allows us to recover a flow-direction-sensitive component of the flow-induced voltage in graphene. The obtained results are discussed in terms of the Coulomb interaction and other phenomena which can be present at the interface of graphene with the aqueous solution.