Chapter 7. Carbon Dots Derived from Natural Carbon Sources: Preparation, Chemical Functionalization, Characterization, and Applications

Abstract

Carbon dots/carbon nanodots/carbon quantum dots (C-Dots/CDs/CQDs) are nascent carbon-based materials in the nano family with several interesting features and characteristics. Generally, they can be defined as tiny surface-functional carbonic nano-particles with a high level and modifiable fluorescence property. These nano-structures have currently gained much prominence in the field of sensors, energy storage, light-emitting diodes, bioimaging, composite products, catalysis, and drug delivery, etc. because of their exceptional chemical, electrical, thermal, and mechanical characteristics. C-Dots can be synthesized basically by two processes i.e., the top-down process mainly including the arc-discharge method, laser ablation, chemical oxidation; and the bottom-up process that comprises of the hydrothermal method, microwave pyrolysis, electrochemical treatment, etc. Due to the incredible properties of these carbon nano-structures, it has become an interesting chapter in the field of nano-research. Moreover, the recent studies focus on the doping/co-doping of C-Dots, synthesis of nanocomposites, and nano-hybrids along with their evolving feasible applications. In this chapter, the key information on C-Dots along with their luminescence mechanism is summarized prior to the progress of C-Dots in preparation techniques, their amazing physical and electronic features, and applications in sensing, catalysis, bio-imaging and optronics. This chapter provides a review on the synthesis of C-Dots from various natural sources including coal and graphite. It also includes some of the important aspects of doping and co-doping C-Dots and formation of nano-composites along with preparation techniques, and their various applications. This chapter provides an overview and outlines the challenges faced while synthesizing C-Dots with different color emissions.