Carbon-dot-based solid-state luminescent materials: Synthesis and applications in white light emitting diodes and optical sensors

Carbon dots (CDs) have been regarded as a new star in the family of carbon nanomaterials, and have been widely studied since they were accidentally discovered in 2004. CD-based solid-state luminescent (CD-SSL) materials have the advantages of being environmentally friendly, non-toxic and low cost, which makes them ideal candidates to replace rare earth/semiconductor quantum dot-based luminescent materials. However, because of their quenching caused by aggregation, it is a great challenge to retain their luminescent properties when they are transferred from solution to the solid state. This review gives a brief introduction to the synthesis methods for CDs, followed by a detailed description of the most widely used strategies for the preparation of CD-SSL materials and their typical applications in white light-emitting diodes and optical sensors. Finally, the shortcomings of current research on CD-SSL materials are discussed, and their future in the above-mentioned as well as other fields is briefly considered.