Control the size and surface chemistry of graphene for the rising fluorescent materials

Fluorescent graphene-based materials, labelled as a sort of fluorescent carbon-based nanomaterial, have drawn increasing attention in recent years. When the size and structure of graphene were controlled properly, photoluminescence was induced in graphene, resulting in the so-called fluorescent graphene (FG). FG has a size-, defect-, and wavelength-dependent luminescence emission, which is similar to traditional semiconductor-based quantum dots. Moreover, with excellent chemical stability, fine biocompatibility, low toxicity, up-conversion emission, pH-sensitivity and resistance to photobleaching, FG promises to offer substantial applications in numerous areas: bioimaging, photovoltaics, sensors, etc. Currently, research works have allowed FG to be produced by many approaches ranging from simple oxidation of graphene to cutting carbon sources and organic synthesis from small molecules. In this Feature Article, we summarize the reported fluorescent graphenes, with emphasis on their category, properties, synthesis and applications. Meanwhile, we give a perspective on their subsequent developments and compare the features of FG and other fluorescent carbon-based materials.