Since carbon dots (CDs) were reported in 2004, they have been widely used in various fields due to their outstanding optical properties. However, most CDs are self-quenched due to the direct π−π interaction in the solid-state aggregation. This shortcoming limits the wide application of CDs, because numerous optoelectronic devices and sensors usually require photoluminescent materials in the solid state. Therefore, designing and preparing carbon dots with multicolor solid emission is necessary. Here, solid-state fluorescence (SSF) CDs were prepared via a one-step solvothermal method, using MA and APTES as raw materials. Through adjusting the ratio of raw materials, solid-state emitting CDs with green, yellow, and orange colors are obtained. The fluorescence spectrum ranges from 490−625 nm, and the QYs are 34.06%, 38.07%, and 20.37%, respectively. For prepared CDs, the main reason for the solid-state emission is that the Si−O, Si−C, and Si−N bonds generated during the formation process can prevent the π−π interaction between the graphitized cores. The red shift mechanism of solid and liquid fluorescence is attributed to the decrease in particle size and the increase in the degree of particle aggregation within the unit range. In addition, based on these excellent photoluminescence properties, we have prepared colored light-emitting diodesthe CIEs are (0.22, 0.41), (0.38, 0.47), and (0.50, 0.43) (Commission Internationale de l'Elcairage coordinate)and solid-state emitting CDs/epoxy films with high transparency and stability.

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by introducing specific recognition groups while significantly improving their optical properties and biocompatibility. [15,16] Surface modification has emerged as a powerful strategy for optimizing the performance of CDs and regulating the surface state.Morin as a polyhydroxy flavonoid is widely found in daily foods and thus is ingested to supplement the body. It exerts a variety of beneficial effects in the body, including scavenging free radicals, fighting inflammation, and protecting nerves, and even has a blocking effect on the growth and proliferation of cancer cells. It is commonly used in clinical practice to treat stomach diseases, chronic inflammatory diseases, coronary heart diseases and cancer. [17][18][19][20] However, studies have shown that high doses of morin can lead to pro-oxidative effects on cells, affecting the absorption of substances, drug metabolism and even DNA damage. On the other hand, heavy metal Al 3+ is an important component often used in food packaging, paper, and pharmaceutical industries. [21][22][23][24] According to the World Health Organization study, the tolerable intake of Al 3+ in the human body is estimated to be less than 4 mg per day. [25] The long-term accumulation of excessive Al 3+ can lead to kidney failure and pose a serious threat to the bones, brain and nervous system. In view of the above, a series of analytical methods have been established for the detection of morin and Al 3+ , including high performance liquid chromatography, electrochemical analysis and gas chromatography. [26,27] The above methods have limitations such as complicated pre-treatment, expensive and difficult operation, while the fluorescence method can overcome the defects of existing methods and establish a simple, rapid and reliable detection method with far-reaching practical application prospects.Based on the above, novel cyan Z-CDs were synthesized by surface modification of CDs through amidation reaction using β-CD (Scheme 1). In particularly, β-CD increased the spatial site resistance between CDs, which effectively suppressed the aggregation quenching effect and improved the luminescence intensity, and this results in excellent dispersion, stability and superior fluorescence properties of Z-CDs. Furthermore, the addition of morin could effectively quenched the fluorescence of Z-CDs and Al 3+ could make rapid recovery of the fluorescence of the Z-CDs-morin. The spectral characterization and Carbon dots (CDs) are emerging photoluminescent materials with excellent optical properties. However, the lack of active sites in primitive CDs has limited their development applications. Herein, functionalized carbon dots (Z-CDs) are successfully prepared by surface modification of CDs with mono (6-amino-6-deoxy) cyclodextrin (β-CD). The introduction of β-CD increases the spatial potential resistance between CDs, which effectively reduces the self-quenching effect. Moreover, the conjugated domains of Z-CDs are expanded, which improves the optical properties with a quantum yield of 48.74%. Z-CDs are ab...

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extensive research in the fields of drug delivery, chemical sensing, bioimaging, and specifically catalysis. [7][8][9] For instance, Liu's group has prepared CDs-confined CoP-CoO nanoheterostructure, Ru@CDs, RuM/CDs (M = Ni, Mn, Cu), and RuCo/ CDs catalysts with excellent catalytic performance, which can be widely used for electrolysis of hydrogen. [10][11][12][13] Catalysis, especially photocatalysis, is a topic that has received a lot of attention recently. Conventional photocatalysts include titanium dioxide, zinc oxide, and cadmium sulfide and many other oxide sulfide semiconductors, but these catalysts are basically limited in their use by low light utilization and high lightinduced electron-hole complexation rates. [14,15] As functional nanomaterials with excellent optical and electronic properties such as efficient light harvesting, extraordinary UCPL, and excellent photoinduced electron transfer, CDs combined with photocatalysts can broaden the photoresponsive region and improve the separation ratio of photoinduced carriers. [16,17] CDs are therefore considered to be an effective component for the construction of high-performance photocatalysts, and this area has been extensively investigated by researchers. CDs/Bi 2 MoO 6 composite photocatalysts were prepared by Samanta et al. [18] CDs led to an increase in catalyst light absorption and carrier separation efficiency. Zha et al. [19] synthesized a photocatalyst CDs/BiOCl using Chlorella vulgaris as a carbon source for CDs (CBOC). The introduced CDs broadened the response range of the spectrum, promoted the separation of electron-hole pairs, and enhanced the photocatalytic efficiency.The photocatalytic mechanism of CDs can be the photoexcitation and charge separation of the core carbon. [20] In general, the photocatalytic process based on CDs is divided into the following three processes. First, the absorption of light leads to the generation of electron-hole pairs. Second, the separation and transfer of electron-hole pairs create prerequisites for the reaction. Finally, a redox reaction takes place on the photocatalytic surface. [21] The main factors limiting the photocatalytic process are light absorption and the rate of electron-hole pair complexation, and many approaches have been taken to alleviate these problems.In view of the excellent performance of CDs in photocatalysis, previous reviews have summarized the approaches to improve the photocatalytic efficiency of CDs and the applications of CDs-based photocatalytic materials. [22][23][24][25][26] However, this thesis provides a review of the recent literature in this With their unique optical and electronic properties, carbon dots (CDs) are showing great momentum in many fields such as biosensing, imaging, drug delivery, and photocatalysis. Due to their efficient light harvesting, extraordinary upconversion photoluminescence, and excellent photoinduced electron transfer capabilities, the combination of CDs with photocatalytic materials will promote light absorption resulting in increased generation...