Carbon dots: An innovative luminescent nanomaterial

Abstract

In recent years, carbon dots (CDs), including carbon nanodots, carbonized polymer dots, carbon quantum dots, and graphene quantum dots have attracted a mounting interest as readily accessible, nontoxic, and relatively inexpensive carbon-based nanomaterials. Yet, despite intense research for a number of years, a unifying picture is still lacking to clarify the exact definition, clear chemical structure, and unique optical properties of this family of nanomaterials. In this review, we systematically summarize the recent development of CDs from molecular design to related properties of excited states as well as their applications in optoelectronic devices and biology. We point out the current challenges, including exploring precise synthesis, clarifying the structure-property relationship, and regulating singlet and triplet states of fluorescence, phosphorescence, and delayed fluorescence. Moreover, the structural optimization of optoelectronic devices, tumor targeting mechanism, selective imaging, and drug delivery of CDs are also highlighted. We hope that the information provided in this review will inspire more exciting research on CDs from a brand-new perspective and promote practical application of CDs in multiple directions of current and future research.

Carbon Dots in Bioimaging, Biosensing and Therapeutics: A Comprehensive Review

“…The synthetic approaches are generally classified into two main categories: top-down and bottom-up. [45][46][47]…”

A Brief Review of Carbon Dots–Silica Nanoparticles Synthesis and their Potential Use as Biosensing and Theragnostic Applications

“…The authors showed that these pink fluorescent CDs can be applied for cancer cell bioimaging, antibacterial activity, and ROS scavenging. Another new topic regarding biomedical application of CDs is related to covering all spectral regions, particularly the near-infrared region [ 59 – 62 ]. Nevertheless, despite all these promising applications of CDs, to date, it is necessary to establish an effective large-scale production synthesis method, standardize the composition and structure of CDs, and achieve a better yield [ 63 – 69 ].…”

“…Nevertheless, despite all these promising applications of CDs, to date, it is necessary to establish an effective large-scale production synthesis method, standardize the composition and structure of CDs, and achieve a better yield [ 63 – 69 ]. In addition, a better comprehension of the nature of the photoluminescence properties is needed [ 59 , 70 ]. Li et al [ 71 ] reported and interestingly achieved the large-scale production of CDs by an aldol condensation reaction at room temperature and ambient pressure.…”

Applications of Carbon Dots in Electrochemical Energy Storage

“…In recent years, CDs with solid-state emission were continuously reported. 24,25 Control and modification of surface electronic states are of significance for realizing the solid-state emission of CDs. In a CPDs system, the polymer's frameworks or cross-linked networks can preclude the rotational motions of fluorophore dots inside, realizing cross-linking-induced solid emission of CPDs.…”