Enhancement of Electrical Conductivity of Graphene-Coated Glass Slides via Sulfuric Acid Chemical Passivation: A Systematic Study Using the Four-Point Probe Method

Abstract

Graphene oxide (GO) is a promising material for electrochemical applications due to its high surface area and functional tunability. However, its inherent electrical resistance—caused by abundant oxygen-containing groups—limits its use in high-performance energy devices. Enhancing its conductivity is essential to unlock its full potential, especially in supercapacitor electrodes. This study demonstrates that sulfuric acid chemical passivation significantly enhances the electrical conductivity of graphene-coated glass slides, with the optimal effect observed at a concentration of 0.6 M. At this concentration, the samples exhibit the lowest resistivity and stable thickness, indicating improved uniformity and minimal structural degradation. However, higher concentrations (0.7 M–0.9 M) lead to over-passivation, causing a decline in conductivity and signs of material degradation. These findings highlight 0.6 M H₂SO₄ as the most effective concentration for boosting graphene’s conductive properties through a simple and scalable post-treatment process. This report delves into the fundamental properties of graphene, the methodology of the four-point probe method for characterization, the underlying mechanisms of sulfuric acid passivation, and recent breakthroughs in scalable graphene production and post-treatment techniques, including key materials and challenges.