Abstract

Fluorescent carbon dots (CDs) are an emerging category of nanomaterials in the carbon family. There are different inexpensive and renewable resources that can be used to synthesize green CDs, which include received immense consideration from researchers because of their improved aqueous solubility, high biocompatibility, and eco-friendly nature compared with chemically derived CDs. Additional surface passivation is not necessary as heteroatoms be present on the surface of green CDs in the form of amine, hydroxyl, carboxyl, or thiol functional groups, which be able to improve their physicochemical properties, quantum yield, and the probability of visible light absorption. Green CDs boast potential applications in the fields of bioimaging, drug/gene delivery systems, catalysis, and sensing. While their discovery, there have been several review articles that describe the synthesis of green CDs and some of their applications. Nevertheless, there are no review articles describing the synthesis and complete applications of green CDs. Here, we provide detailed information concerning their synthesis and applications based on the available literature. In addition, we discuss a number of the less explored applications of green CDs and the challenges that continue to be overcome.