A graphene chemosensor lab-on-a-PCB platform for multi-analyte detection
Author(s)
Fenech Salerno, Benji
Type
Thesis
Abstract
In this thesis, I will describe the development of a graphene-based chemosensing platform for multi-analyte sensing. In Chapter 2, I introduce the fundamental principles of chemosensing, particularly electrochemical chemosensors and the strategies for enhancing performance. Chapter 3 will review graphene and its related materials, highlighting how their synthesis and properties can be tailored and utilised in chemical sensing. Chapter 4 will present an overview of this work's fabrication and characterisation techniques. In Chapter 5, I will present the criteria for identifying a scalable LPEG ink formulation which will be referenced to a GO ink. In this chapter, I will characterise the inks’ concentration, stability, flake size statistics, physical ink properties and flake crystal quality. In Chapter 6, the focus will be on the fabrication of the EG-GFET Lab-on-PCB platform. I will demonstrate how to improve electrode inertness using electroplating. Protocols for LPEG and GO ink deposition and post-deposition processing are presented. I will then evaluate different reference electrode materials and show how the solid contact Ag/AgCl reference electrode shows the superior performance of the evaluated reference electrode types. In Chapter 7, I will demonstrate how the EG-GFET Lab-on-PCB test strips can serve as a reliable Lab-on-PCB platform for sensing pH and Na+. The performance of the EG-GFET device towards each analyte will be validated in terms of the LoD, sensitivity, response time, and linear range. The influence of LPEG or rGO channel materials on pH sensitivity will be investigated, with LPEG-15 identified as the top-performing material. Lastly, the EG-GFET channel will be functionalised with an ISM and selectivity to interfering molecules will also be assessed for both the bare channel devices and the ISM device to validate their performance for sensing in complex mixtures.
Version
Open Access
Date Issued
2023-07-05
Date Awarded
2024-02-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
Advisor
Torrisi, Felice
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)