A review of fluorescent carbon dots: Synthesis, photoluminescence mechanism, solid-state photoluminescence and applications in white light-emitting diodes

Carbon nanomaterials with a size of less than 10 nm, fluorescent carbon dots (CDs), have been extensively investigated, due to their excellent fluorescence tunability, good biocompatibility, wide range of precursors and low cost. Moreover, their simple preparation and excellent performance provide for a wide range of applications in the fields of optical sensing, energy storage, biomedical imaging, and white light-emitting diodes (WLEDs). A large number of solid-state photoluminescent CDs have recently been developed and used in WLEDs. The synthesis strategies of CDs are briefly summarized and their photoluminescence mechanisms are reviewed as well as the recent progress for their use in WLEDs. Finally, prospects for solving the current problems and challenges of CDs for WLEDs are briefly presented and discussed.