Application of Carbonaceous Quantum dots in Energy Storage

Carbon quantum dots (CQDs) are a type of carbon nanomaterial that has lately received attention as a potential replacement for standard semiconductor quantum dots (QDs). CQDs feature a quasi-spherical structure and amorphous to nanocrystalline carbon cores with diameters of 10-20 nm. Based on the carbon core, CQDs are further classified as graphene quantum dots (GQDs), carbon nanodots (CNDs), and polymer dots (PDs). CQDs exhibit unique electrical and optical properties due to their bigger edge effects and quantum confinement; better than graphene oxide nanosheets, they can also be easily split into electrons and holes due to their high dielectric constant and extinction coefficient. CQDs are crucial in the sector of energy storage and transformation because CQDs offer the advantageous properties of low toxicity, environmental friendliness, low cost, photostability, favourable charge transfer with increased electronic conductivity, and comparably simple synthesis processes. Due to their superior crystal structure and surface properties, CQD nanocomposites often helped to shorten charge transfer paths and maintain electrode material cycle stability. CQDs provide cost-effective and environmentally friendly nanocomposites used for supplying high energy density and stable electrodes for energy storage applications. This chapter provides a summary of the role that CQDs play in energy transmit technologies, including solar cells, supercapacitors, lithium-ion batteries, and hydrogen and oxygen evolution reactions.