Small nanoparticles bring big prospect: The synthesis, modification, photoluminescence and sensing applications of carbon dots

As a new type of carbon-based fluorescent nanomaterials, carbon dots (CDs) are provided with the advantages of small size, excellent photoluminescence (PL) property, easy surface modification, robust stability, good water solubility and biocompatibility, which endow them with great potential in sensing. In this review, we first describe the preparation of CDs from different starting materials via various techniques, and pre-/post-modification strategies to modulate their PL properties. Second, we outline the optical properties of CDs, including UV-vis absorption and PL, especially the PL mechanisms of CDs are presented in detail from the size effect, molecular state, surface state and defect state. Third, we summarize the research progress of CDs in sensing environmental pollutants, bioactive substances, biological microenvironments, bacteria and viruses via different mechanisms. In addition, we envision the future development trends and prospects for CDs-based nanosensors. We believe that this type of small nanoparticles will bring about big prospect in the near future. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

This review introduces carbon dots as a new type of carbon-based fluorescent nanomaterials with great potential in sensing. The preparation methods and strategies to modulate the photoluminescence properties of carbon dots from different starting materials are described. The optical properties and photoluminescence mechanisms of carbon dots are outlined. The research progress of carbon dots in sensing environmental pollutants, bioactive substances, bacteria, and viruses via different mechanisms is summarized. Additionally, the future development trends and prospects for carbon dots-based nanosensors are envisioned.