An overview of the synthesis, optical properties, luminescence mechanism, and optoelectronic applications of CQDs is presented.

Traditional asymmetric supercapacitors are severely restricted due to the low specific capacitance of carbon negative materials. The rational design of positive and negative electrodes that afford the asymmetric device with high performances is particularly important. In this paper, we fabricate a novel cost-effective and environmental-friendly aqueous asymmetric supercapacitor by using CuCo 2 O 4 /CuO nanowire arrays as positive electrode and RGO/Fe 2 O 3 composites as negative electrode. The assembled device exhibits a high energy density of 33.0 Wh kg -1 at a power density of 200 W kg -1 , and can still operate at a high power density of 8.0 KW kg -1 with an energy density of 9.1 Wh kg -1 . The current strategy will provide a fresh route for design and fabricate of novel asymmetric supercapacitors with both high energy density and high power density.

In this mini review, we update the latest research in the design of high-performance WLEDs with different correlated color temperatures by tuning the red component using red emissive CQDs and single-component white emissive CQDs.

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.

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Carbon quantum dots (CQDs) have developed into prospective nanomaterials for next-generation lighting and displays due to their intrinsic advantages of high stability, low cost, and environmental friendliness. However, confined by the spin-forbidden nature of triplet state transitions, the highest theoretical value of external quantum efficiency (EQE) of fluorescent CQDs is merely 5%, which fundamentally limits their further application in electroluminescent light-emitting diodes (LEDs). Soluble phosphorescent CQDs offer a means of breaking the shackle to achieve efficient monochromatic electroluminescence, especially red emission, which is a pivotal constituent in full-color displays. Here, the synthesis of red (625 nm) phosphorescent carbon quantum dot organic frameworks (CDOFs) with a quantum yield of up to 42.3% and realization of high-efficiency red phosphorescent electroluminescent LEDs are reported. The LEDs based on the CDOFs exhibited a red emission with a maximum luminance of 1818 cd m −2 and an EQE of 5.6%. This work explores the possibility of a new perspective for developing high-performance CQD-based electroluminescent LEDs.

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