Electrical Devices based on Graphene Derivatives: Functionalization and Control of Interfaces

• Grant number: 25/06428-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2025
• End date: July 31, 2027
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Rafael Furlan de Oliveira
• Grantee: Matheus da Silva Corsino
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Associated research grant: 21/06238-5 - Functionalized solution-processed 2D materials: development of prototyping electric sensors and biosensors, AP.JP

Abstract

Two-dimensional lamellar materials (2DMs) are currently one of the major research focuses worldwide, whether for fundamental studies of their properties or for the development of new technological applications. Among the various existing 2DMs, graphene oxide (GO) stands out as one of the most attractive materials due to its simple, high-yield production through the oxidation of graphite, which is also compatible with non-toxic solvents. GO consists of a sheet of carbon atoms arranged in a hexagonal lattice with an abundance of oxygen-containing groups located on its basal plane, resulting in low electronic delocalization and, consequently, insulating behavior (Rs > 10¹² ¿/square). Because of this, its applicability in electronic devices is limited. However, its conductivity can be improved through chemical, thermal, or electrochemical reduction methods, producing reduced graphene oxide (rGO). rGO becomes a more versatile 2DM because it combines some characteristics of its precursor-such as low cost and water processability-with high (and tunable) electrical conductivity (Rs < 10³ ¿/square). It also retains the presence of oxygenated groups that cannot be completely eliminated during the reduction process. These groups become important for the functionalization of these materials with molecules or polymers, thereby imparting new properties to the 2DM and enabling the development of new applications. This functionalization process can significantly impact the electrical characteristics of various types of devices, influencing, for example, charge carrier injection or the trap density at dielectric surfaces. Moreover, the functionalization of GO and rGO is a well-established topic in the literature, with numerous strategies employing a wide range of molecules and polymers for different applications. Specifically, in the context of device applications, the focus is primarily on sensors and biosensors, where functionalization plays a key role in providing selectivity toward a given analyte. Frequently, this functionalization of GO and rGO occurs through the anchoring of receptors or biomolecules onto their surfaces, keeping them accessible for interaction with the target analyte. However, there is often a lack of information on how the device interface is affected (or governed) by functionalization, or how the performance of these devices can be tuned to achieve better outcomes. In this context, this project aims to study how the electrical characteristics of devices based on GO and rGO can be tuned through the functionalization of these materials and their interfaces with polymers and molecules containing electron-donating and electron-accepting groups, characterizing their electrical properties via DC and AC measurements. Specifically, the project aims to study field-effect devices such as thin-film transistors and varactors to understand their interfaces and demonstrate their application as chemical sensors and biosensors for the detection of species in solution. (AU)