“…CDs possess many characteristics, such as excellent tunable optical properties, favorable biocompatibility, a wide range of raw material sources, and low cost . Since CDs were first discovered in 2004, researchers have devoted a great deal of effort to the related study of CDs, and various synthesis methods have successively appeared on the historical stage, which are mainly divided into two categories, namely, top-down and bottom-up . Specifically, the top-down method refers to the stripping of large carbon sources to small fragments through physical or chemical methods, mainly including arc discharge, â laser ablation, , electrochemical synthesis, , and nanoetching. , However, the bottom-up method is usually used to synthesize quasi-spherical carbon nanoparticles from small molecular or polymer precursors, including combustion, pyrolysis, hydrothermal/solvothermal pyrolysis, â and microwave-assisted pyrolysis. , Although there are various synthesis methods, most of the currently synthesized CDs emit blue/green fluorescence, and the fluorescent CDs with a long wavelength and high photoluminescence quantum yields (PLQYs) are difficult to obtain, which greatly limits the application of CDs in optoelectronic devices, biological imaging, and other fields.…”