Luminescent Carbon Dots: Characteristics and Applications

Carbon Quantum Dots, or just Carbon Dots (C-Dots) are a recently discovered new class of fluorescent materials from the nano-carbon family. These C-Dots have come forth as potential competitors for inorganic quantum dots (QDs) and other toxic, heavy-metal based materials, because of their characteristics like low toxicity, elemental abundance and biocompatibilty. In the last decade, numerous C-Dots synthesis routes have been developed, and it has been observed that different synthesis methods lead to different carbogenic core and surface structure, along with different characteristic properties related to their composition, luminescence, functionalization, bio-compatibility, surface passivation, etc. In this review, it is discussed how these different synthesis routes and properties of C-Dots can be advantageous in their use in applications in the fields of bioimaging and medicine, optoelectronic devices, chemical and bio-sensing, etc. The report mainly focuses on the luminescence behaviour of these C-dots, discussing their tunable optical behaviour and excitation dependent emission, good electron donor and acceptor tendencies, appreciable quantum yield (QY), electron and charge transfer property, etc., and how can these be used efficiently over the existing materials and techniques for the aforementioned applications.