Critical Analysis of Microwave Heating Mechanisms in Carbon Quantum Dot Synthesis

Abstract

The unique characteristics of carbon quantum dots (CQDs), including their high water solubility, outstanding photostability, programmable photoluminescence, and non-toxicity, have made them a very promising family of nanomaterials. Under the bottom-up technique, microwave-assisted synthesis has drawn a lot of interest among different synthesis methodologies since it is quick, more greener and energy-efficient. This method produces CQDs with improved quantum yield, tunable emission wavelength and a greater yield and purity by allowing for homogeneous heating, shorter reaction periods, fewer side reactions. The size, shape, surface functionalization, and emission properties of the CQDs are all significantly influenced by the precursor selection, especially with regard to amino acids and carbohydrates. The mechanism of microwave heating are highlighted such as dipole and interfacial polarization as well as resistive or conduction heating as well as mechanism of microwave losses are discussed such as dielectric, conduction, and magnetic losses. The study also examines the benefits and drawbacks of alternative techniques, including hydrothermal, pyrolysis, combustion, and template approaches, in comparison to microwave synthesis. The impact of precursor chemistry and reaction parameters on the level of carbonization and surface characteristics is also covered. Despite obstacles including uneven heating and scalability problems, microwave-assisted synthesis provides an environmentally friendly, effective, and adaptable path to CQDs that can be used for a variety of bioimaging, sensing, and optoelectronic applications.