Graphene oxide vacancies-assisted low temperature synthesis of graphitic carbon quantum dots for enhanced conductive networks in epoxy composites

Abstract

Conventional bottom-up synthesis of graphitic carbon quantum dots (g-CQDs) often requires extended reaction times, high energy input, and specialized equipment, limiting scalability and sustainability. In this study, we present an eco-friendly and energy-efficient method for synthesizing g-CQDs using H₂CO₃ as a carbon precursor at just 72 °C for 1 hour—representing one of the lowest reported synthesis temperatures and shortest reaction times using simple apparatus. Graphene oxide vacancies act as catalytic and nucleation sites, promoting the formation of g-CQDs under these mild conditions. The resulting g-CQD solution exhibits strong yellow photoluminescence, with a maximum emission at 533 nm and excitation-independence across the 320–410 nm range. Upon drying, the g-CQDs spontaneously assemble into a three-dimensional (3D) network, which provides additional functionality when incorporated into g-CQD/graphene nanoplatelet epoxy composites. This strategy not only promotes the sustainable production of g-CQDs but also broadens their potential for use in next-generation nanomaterials and optoelectronic devices.