Graphitic Carbon Nitride Quantum Dots (g-C₃N₄ QDs): From Chemistry to Applications

Since their emergence in 2014, graphitic carbon nitride quantum dots (g-C₃N₄ QDs) have attracted much interest from the scientific community due to their distinctive physicochemical features, including structural, morphological, electrochemical, and optoelectronic properties. Owing to their desirable characteristics, such as non-zero band gap, ability to be chemically functionalized or doped, possessing tunable properties, outstanding dispersibility in different media, and biocompatibility, g-C₃N₄ QDs have shown promise for photocatalysis, energy devices, sensing, bioimaging, solar cells, optoelectronics, among other applications. As these fields are rapidly evolving, it is very strenuous to pinpoint the emerging challenges of the g-C₃N₄ QDs development and application during the last decade, mainly due to the lack of critical reviews of the innovations in the g-C₃N₄ QDs synthesis pathways and domains of application. Herein, an extensive survey is conducted on the g-C₃N₄ QDs synthesis, characterization, and applications. Scenarios for the future development of g-C₃N₄ QDs and their potential applications are highlighted and discussed in detail. The provided critical section suggests a myriad of opportunities for g-C₃N₄ QDs, especially for their synthesis and functionalization, where a combination of eco-friendly/single step synthesis and chemical modification may be used to prepare g-C₃N₄ QDs with, for example, enhanced photoluminescence and production yields.