Characterization and Optimization of Reduced Graphene Oxide for Industrial Applications—Insights from Raman Spectroscopy and Correlated Spectroscopy

Reduced graphene oxide (rGO) and graphene oxide (GO) are key 2D materials with significant potential for a wide range of industrial applications, although their precise evaluation and hybrid electrical properties pose notable challenges. In this study, we synthesize findings from two comprehensive investigations to address these issues, focusing on the characterization and application of carbon nanostructures. First, we investigate the degree of reduction of rGO using Raman spectroscopy. We propose the intensity ratio of D* to G band as a novel indicator of rGO quality. Through systematic thermal treatment of GO (100-900 °C) and subsequent spectral analysis, we establish a robust correlation between the D*/G intensity ratio and the C/O atomic ratio. This relationship, elucidated by density functional perturbation theory calculations, provides a reliable metric for assessing rGO quality and understanding its atomic vibrational properties. Second, we investigate the hybrid electrical properties of GO by correlating infrared and ultraviolet-visible absorption spectroscopy using advanced imaging techniques. We identify C-H and C-O rich regions by infrared imaging and analyze their electronic behavior by ultraviolet-visible absorption spectra. Our results show that C-H and C-O rich regions absorb distinctively at 280 nm (4.43 eV) and 380 nm (3.26 eV), respectively. These correlations are validated by several GO flakes and supported by density functional theory calculations. Together, these studies provide a comprehensive approach to evaluate and optimize rGO and GO for diverse applications such as electronic devices, energy storage, and chemical sensors. Our findings contribute to a broader understanding of carbon nanostructures, paving the way for advanced applications and emerging technologies.<br/><br/>[1] A. Lee <i>et al.</i>, <i>Applied Surface Science</i><i>.</i>, vol. 536, p. 147990, (2021).<br/>[2] J. Yoo <i>et al.</i>, <i>Applied Surface Science, </i>vol. 613, p. 155885, (2023).