A Comprehensive Review on the Synthesis, Doping, and Characterization Techniques of Carbon Quantum Dots for Their Multifaceted Applications

A novel class of nanomaterials known as carbon quantum dots (CQDs) has drawn significant attention because of numerous benefits, particularly its small size (between 1 and 10 nm) and great water solubility, fluorescence, ease of synthesis, and low toxicity among others. There are still many crucial questions that need to be answered, such as how to prepare high-quality CQDs with an appropriate yield using a simpler and easier approach. Most of the articles reviewed have discussed the production of CQDs intended for applications in imaging and sensing. Nevertheless, there is a scarcity of research focusing on producing undecorated and doped CQDs. In this review paper, the various methods for synthesizing CQDs by using various carbon sources have been summarized. Additionally, In this paper, we discuss the primary characterization techniques and the applications of CQDs in various fields. The fundamental objective of this paper is to analyze various synthesis methods used over different periods to address the challenges that one might encounter during the synthesis of CQDs.