Multifunctional Hybrids of Graphene Quantum Dots with Inorganic Nanoparticles (Metal, Metal Oxide and MOF) - Topical State and Evolutions

Carbon based quantum dots have been discovered as unique florescent nanoentities having different types, such as carbon nanodots, graphene quantum dots, and polymer dots. Out of these, graphene quantum dots can be seen as zero dimensional derivatives of graphene (2 dimensional nanosheet). Due to recent advancement in the field of graphene quantum dots, various inorganic and organic hybrids have been reported in the literature so far. In this concern, inorganic nanoparticles like metal, metal oxide, as well as metal organic framework (MOF) have been used to design graphene quantum dots/metal nanoparticles, graphene quantum dots/metal oxide nanoparticles, and graphene quantum dot/MOF type hybrids. These nanomaterials have been designed using efficient synthesis strategies including hydrothermal, solvothermal, freeze dying, solution, in situ, and several other methods. Accordingly, this state-of-the-art review article aims to highlight advantageous physical properties, such as microstructure, electron/charge conduction, florescence, catalytic activity, etc., in addition to dispersion, compatibility, and interface formation of graphene quantum dots with inorganic nanoparticles. Consequently, high tech application areas of graphene quantum dots/inorganic nanoparticle hybrids have been identified for optical sensors, supercapacitors, photocatalysts for environmental treatment, and antimicrobials for wound healing purposes. Despite the success of graphene quantum dots/inorganic nanoparticle hybrids so far, focused future research efforts on these nanomaterials may lead to large/commercial scale applications in energy, electronics, environment, and biomedical fields by overcoming underlying design/synthesis/performance challenges. HIGHLIGHTS Graphene quantum dots recognized as unique 0-dimensional graphene derivatives having inherent quantum confinement, surface/edge effects, florescence, and innumerable beneficial physical characteristics. Hybrids of graphene quantum dots with inorganic nanoparticles, like metal, metal oxide, and MOF, designed using efficient processing techniques (hydrothermal, solvothermal, solution, etc.). Graphene quantum dot/inorganic hybrids investigated for design variations, microstructure, electron/charge conductivity, florescence, catalytic activity, antimicrobial nature, etc. Fine dispersion, compatibility, and interfacial effects of graphene quantum dots with inorganic nanoparticles led to high tech applications for optical sensors, photocatalysts, supercapacitors, and wound healing purposes. Future research on advanced graphene quantum dot/inorganic hybrids using novel nanostructural designs, optimum synthesis tactics, and overcoming field challenges desirable for industrial applications in energy, electronics, environment, and biomedical fields. GRAPHICAL ABSTRACT