Application of Ion Beam Irradiation for Engineering of Graphene Oxide-Based Environmental Sensors

Abstract

Graphene oxide (GO) plays a significant role in scientific research due to its versatile surface chemistry and 2D structure. The adaptability of material makes it ideal for applications in sensors and energy storage. The structure and degree of oxidation of GO are closely linked to its electrical properties. Ion beam irradiation can selectively modify the oxidation degree of GO by removing oxygen-containing groups, depending on the beam energy and type. This process also introduces controlled defects into GO that tailor its electronic, mechanical, and surface characteristics. However, it is crucial to find a balance, or a 'sweet spot', where sufficient reduction enhances conductivity while preserving the integrity of the sp² carbon network. In this work GO, GO/12-tungstophoshoric acid and GO/cobalt-ferrite thin films were deposited on interdigitated electrode arrays (IDE) and irradiated with carbon ion beams of 2 MeV energies and fluences from 1013 to 1015 ions/cm2. The electric properties of pristine and irradiated samples were investigated with electrochemical impedance spectroscopy method and correlated to oxidation degree obtained by X-ray photoelectron spectroscopy and structural properties obtained by Raman spectroscopy. The results outline the positive effect of ion beam irradiation on electric properties of all samples, where increased reduction of GO with increasing fluence lead to lower impedance values. Electric properties of obtained samples were tested in various environmental conditions to test the applicability in sensor devices.