Fabrication, optical and ion conduction properties of reduced graphene oxide quantum dots and application in electrolyte supercapacitor devices

Abstract

Reduced graphene oxide quantum dots (rGO-QDs) were synthesized via the hydrothermal method and characterized for their structural, optical, and ion conduction properties. Raman spectroscopy confirmed a low defect density (ID/IG ratio: 0.91), while X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed reduced interlayer spacing and particle sizes (∼4.14 nm), indicative of quantum confinement effects. Optical analysis demonstrated tunable photoluminescence and strong absorption, confirming their quantum dot nature. Electrochemical impedance spectroscopy (EIS) highlighted enhanced ionic conductivity and reduced internal resistance in supercapacitor devices utilizing KOH/rGO-QDs electrolytes, improving specific capacitance and ion transport. These results establish rGO-QDs as promising materials for optoelectronics and energy storage applications, particularly in high-performance supercapacitors.