Synthesis of Carbon Dots with Strong Luminescence in both Dispersed and Aggregated States by Tailoring Sulfur Doping

Author(s):  
Xianjing Li ◽  
Mengdan Zheng ◽  
Haijing Wang ◽  
Yuan Meng ◽  
Duan Wang ◽  
...  
2020 ◽  
Vol 32 (7) ◽  
pp. 857-867
Author(s):  
Jingjing Bai ◽  
Weijie Ren ◽  
Yulong Wang ◽  
Xiaoxia Li ◽  
Cheng Zhang ◽  
...  

In this work, high-performance thermoplastic polyurethane elastomer/carbon dots (TPU/CDs) bulk nanocomposites with strong luminescence were fabricated via in situ polymerization. The CDs were synthesized from citric acid and 2-aminothiophenol. Transmission electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and systematic characterization indicated the formation of the CDs and the covalent conjugation of the CDs with TPU. The optical properties of the TPU/CDs nanocomposites were characterized by ultraviolet–visible and fluorescence spectroscopy. Compared to the initial solid-state CDs (the absolute photoluminescence quantum yields (QY): 20%), all the composites exhibited stronger luminescence behavior. When the CDs content was 0.5 wt%, the QY was as high as 68%. Furthermore, the rheological, mechanical, and thermal properties of the nanocomposites were investigated. The rheological properties established the structure–property relationships of the composites. The incorporation of the CDs enhanced the elastic response in viscoelasticity of the nanocomposites. The tensile strength of 1.0 wt% CDs loaded TPU increased from 18.2 MPa to 28.6 MPa, nearly 57% higher than that of the neat TPU. Given the excellent Ag+ detection performance of the CDs, the high QY and the processability of the nanocomposites, Ag+ detection experiments for the composite film were performed. The study will facilitate the applications of luminescent nanocomposites in potential fields.


2021 ◽  
Author(s):  
Guohua Cao ◽  
Zhifei Wei ◽  
Yuehong Yin ◽  
Lige Fu ◽  
Yukun Liu ◽  
...  

2020 ◽  
Vol 388 ◽  
pp. 124199
Author(s):  
Dong Gao ◽  
Yusheng Zhang ◽  
Amin Liu ◽  
Yuda Zhu ◽  
Suping Chen ◽  
...  

Author(s):  
Khalilalrahman Dehvari ◽  
Sheng-Hui Chiu ◽  
Jin-Sheng Lin ◽  
Wubshet Mekonnen Girm ◽  
Yong-Chien Ling ◽  
...  

2020 ◽  
Vol 25 (46) ◽  
pp. 4848-4860 ◽  
Author(s):  
Anisha Anand ◽  
Gopinathan Manavalan ◽  
Ranju Prasad Mandal ◽  
Huan-Tsung Chang ◽  
Yi-Ru Chiou ◽  
...  

: The prevention and treatment of various infections caused by microbes through antibiotics are becoming less effective due to antimicrobial resistance. Researches are focused on antimicrobial nanomaterials to inhibit bacterial growth and destroy the cells, to replace conventional antibiotics. Recently, carbon dots (C-Dots) become attractive candidates for a wide range of applications, including the detection and treatment of pathogens. In addition to low toxicity, ease of synthesis and functionalization, and high biocompatibility, C-Dots show excellent optical properties such as multi-emission, high brightness, and photostability. C-Dots have shown great potential in various fields, such as biosensing, nanomedicine, photo-catalysis, and bioimaging. This review focuses on the origin and synthesis of various C-Dots with special emphasis on bacterial detection, the antibacterial effect of CDots, and their mechanism.


2018 ◽  
Vol 15 (1) ◽  
pp. 47-55
Author(s):  
Xuebing Li ◽  
Haifen Yang ◽  
Ning Wang ◽  
Tijian Sun ◽  
Wei Bian ◽  
...  

Background: Morin has many pharmacological functions including antioxidant, anticancer, anti-inflammatory, and antibacterial effects. It is commonly used in the treatment of antiviral infection, gastropathy, coronary heart disease and hepatitis B in clinic. However, researches have shown that morin is likely to show prooxidative effects on the cells when the amount of treatment is at high dose, leading to the decrease of intracellular ATP levels and the increase of necrosis process. Therefore, it is necessary to determine the concentration of morin in biologic samples. Method: Novel water-soluble and green nitrogen and sulfur co-doped carbon dots (NSCDs) were prepared by a microwave heating process with citric acid and L-cysteine. The fluorescence spectra were collected at an excitation wavelength of 350 nm when solutions of NSCDs were mixed with various concentrations of morin. Results: The as-prepared NSCDs were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The fluorescence intensity of NSCDs decreased significantly with the increase of morin concentration. The fluorescence intensity of NSCDs displayed a linear response to morin in the concentration 0.10-30 μM with a low detection limit of 56 nM. The proposed fluorescent probe was applied to analysis of morin in human body fluids with recoveries of 98.0-102%. Conclusion: NSCDs were prepared by a microwave heating process. The present analytical method is sensitive to morin. The quenching process between NSCDs and morin is attributed to the static quenching. In addition, the cellular toxicity on HeLa cells indicated that the as-prepared NSCDs fluorescent probe does not show obvious cytotoxicity in cell imaging. Our proposed method possibly opens up a rapid and nontoxic way for preparing heteroatom doped carbon dots with a broad application prospect.


2020 ◽  
Vol 16 ◽  
Author(s):  
Pan Zhang ◽  
Shun-Sheng Zhao ◽  
JiaJia Wang ◽  
Xiang Rong Liu

Background: In recent years, environmental pollution and heavy metal pollution caused by rapid urbanization and industrialization have become increasingly serious. Among them, mercury (II) ion (Hg2+) is one of the highly toxic heavy metal ions, and its pollution comes from various natural resources and human activities. Therefore, people attach great importance to the development of analytical methods for effective analysis and sensitive detection of Hg2+ . Objective: Using grape skin as a green and environmental friendly carbon source, to synthesize fluorescent carbon dots, and try to apply them to the detect the concentration of Hg2+ in water. Method: Using "Hutai No. 8" grape skin as carbon source, fluorescent carbon dots were synthesized by one-step hydrothermal method. Structure and fluorescent properties of the carbon dots were tested using TEM, XPS, XRD and other characterization instruments, and their utilization on detection of mercury ions in the actual water samples was explored. Results: The CDs had a particle size of about 4.8 nm and a spherical shape. There are N-H, C-N, C=O and other functional groups on the surface. It was found that Hg2+ has obvious fluorescence quenching effect on CDs, and thus CDs fluorescence quenching method to detect the concentration Hg2+ was established, and the detection limit is 3.7 μM, which could be applied to test the concentration of Hg2+ in water samples. Conclusion: Using grape skin as carbon source, fluorescent carbon dots were successfully synthesized by hydrothermal method. Carbon dots were used to detect mercury ions in water, and a method for detecting mercury ions in actual water samples was established.


2020 ◽  
Vol 231 (4) ◽  
pp. S180
Author(s):  
Athina L. Yoham ◽  
Carolina M. Matta ◽  
Sabrin B. Safar ◽  
Meghana Sankaran ◽  
Anastasiia Kaplina ◽  
...  

2019 ◽  
Vol 411 (8) ◽  
pp. 1647-1657 ◽  
Author(s):  
Pengli Zuo ◽  
Jianhua Liu ◽  
Hongna Guo ◽  
Chenghong Wang ◽  
Hongqian Liu ◽  
...  

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