Graphitic and amorphous C-dots share common characteristics in their photoluminescence behavior. However, the graphitic dots have a lead as electrocatalyst for fuel cells, sensitizers, and electron acceptors for solar cells.
The emergence of carbogenic nanoparticles (C-dots) as a new class of photoluminescent (PL) nanoemitters is directly related to their economical preparation, nontoxic nature, versatility, and tunability. C-dots are typically prepared by pyrolytic or oxidative treatment of suitable precursors. While the surface functionalities critically affect the dispersibility and the emission intensity of C-dots in a given environment, it is the nature of the carbogenic core that actually imparts certain intrinsic properties. Depending on the synthetic approach and the starting materials, the structure of the carbogenic core can vary from highly graphitic all the way to completely amorphous. This critical review focuses on correlating the functions of C-dots with the graphitic or amorphous nature of their carbogenic cores. The systematic classification on that basis can provide insights on the origins of their intriguing photophysical behavior and can contribute in realizing their full potential in challenging applications.