Multicolor solid-state fluorescence and multicolor afterglow carbon dots: preparation, luminescence regulation, and applications

Carbon dots (CDs), as emerging luminescent materials, have attracted extensive attention from researchers because of their excellent optical properties. However, most reported CDs currently exhibit only a single luminescent color, and research on achieving multicolor solid-state fluorescence (SSF) and multicolor afterglow with CDs is relatively limited. In recent years, increasing research on multicolor SSF and multicolor afterglow CDs has greatly expanded the potential of CDs in various application fields. In this review, we review the research progress on multicolor luminescent CDs from three aspects: synthesis methods, mechanisms and applications. In particular, methods for realizing multicolor luminescence of CDs are summarized in detail, and the multicolor luminescence mechanisms of different realization methods are discussed, which cover multiple aspects, such as element doping, adjustment of the reaction parameters, surface state modulation, CDs with multiple luminescence centers, energy transfer, and matrix assistance. Then, we introduce the applications of multicolor luminescent CDs in the fields of fingerprint identification, optoelectronic devices, sensors, information encryption and advanced anticounterfeiting. Finally, we present and discuss the challenges and developments of multicolor SSF and multicolor afterglow CDs.