scholarly journals Tuneable properties of carbon quantum dots by different synthetic methods

2021 ◽  
Author(s):  
A. R. Nallayagari ◽  
E. Sgreccia ◽  
R. Pizzoferrato ◽  
M. Cabibbo ◽  
S. Kaciulis ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Microwave Irradiation ◽  
Surface States ◽  
Carbon Quantum Dots ◽  
Synthetic Methods ◽  
Synthesis Methods ◽  
Photoluminescence Spectra ◽  
Direct Introduction ◽  
Nitrogen Containing Compounds ◽  
Post Functionalization

AbstractCarbon quantum dots (CQD) were prepared from three different precursors and by three bottom-up synthesis methods: classical pyrolysis of citric acid (CAP), microwave irradiation of glucose (GM), and hydrothermal treatment of glucosamine hydrochloride (GAH). CQD were further functionalized using various nitrogen-containing compounds: 6-aminohexanoic acid, 1,6-diaminohexane, N-octylamine, dimethylamine, and tryptophan. Special attention was dedicated to investigate how the combination of synthetic method and starting material affected the nature and properties of CQD. The analysis indicated that CAP were good candidates for covalent post-functionalization, GM allowed an easy passivation, and GAH permitted the direct introduction of nitrogen into the core. The size distribution showed a core–shell structure for CQD functionalized with an aminoacid by microwave irradiation, whereas the thermal decomposition evidenced the degradation of functionalizing molecules and the presence of pyridinic and pyrrolic nitrogen after hydrothermal synthesis. Photoluminescence spectra revealed important differences between the synthesis techniques, related to the occurrence of surface states, and the highest fluorescence quantum yield for hydrothermally prepared CQD. These approaches led to CQD with properties that can be exploited in many fields from energy conversion to sensing.

Photoluminescence enhancement via microwave irradiation of carbon quantum dots derived from solvothermal synthesis of l-arginine

2019 ◽  
Vol 43 (2) ◽  
pp. 689-695 ◽  
Author(s):  
Khalid M. Omer ◽  
Kosar H. Hama Aziz ◽  
Yousif M. Salih ◽  
Diary I. Tofiq ◽  
Aso Q. Hassan
Keyword(s):  
Quantum Dots ◽  
Microwave Irradiation ◽  
Solvothermal Synthesis ◽  
Carbon Quantum Dots ◽  
Photoluminescence Enhancement

Photoluminescence enhancement of carbon quantum dots was achieved via solvothermal synthesis followed by microwave irradiation.

Full-color-emission carbon quantum dots by controlling surface states in a system of solvent

2021 ◽  
pp. 118614
Author(s):  
Yaoyao Yang ◽  
Kangliang Peng ◽  
Yakun Deng ◽  
Youjun Zhao ◽  
Jinshui Ai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Surface States ◽  
Carbon Quantum Dots ◽  
Full Color ◽  
Color Emission

scholarly journals Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

2019 ◽  
Vol 5 (2) ◽  
pp. 24 ◽  
Author(s):  
Ganeshlenin Kandasamy
Keyword(s):  
Quantum Dots ◽  
Optical Sensors ◽  
Carbon Nanomaterials ◽  
Synthesis Method ◽  
Carbon Quantum Dots ◽  
Carbon Nanodots ◽  
Synthesis Methods ◽  
Sensing Applications ◽  
Potential Applications ◽  
Co Doped

Carbon quantum dots (CQDs)/carbon nanodots are a new class of fluorescent carbon nanomaterials having an approximate size in the range of 2–10 nm. The majority of the reported review articles have discussed about the development of the CQDs (via simple and cost-effective synthesis methods) for use in bio-imaging and chemical-/biological-sensing applications. However, there is a severe lack of consolidated studies on the recently developed CQDs (especially doped/co-doped) that are utilized in different areas of application. Hence, in this review, we have extensively discussed about the recent development in doped and co-doped CQDs (using elements/heteroatoms—e.g., boron (B), fluorine (F), nitrogen (N), sulphur (S), and phosphorous (P)), along with their synthesis method, reaction conditions, and/or quantum yield (QY), and their emerging multi-potential applications including electrical/electronics (such as light emitting diode (LED) and solar cells), fluorescent ink for anti-counterfeiting, optical sensors (for detection of metal ions, drugs, and pesticides/fungicides), gene delivery, and temperature probing.

scholarly journals Rapid Synthesis of highly luminescent Carbon Quantum Dots using Low-Pressurized Microwave Solvothermal Heating

2019 ◽  
Author(s):  
Kenta Hagiwara ◽  
Satoshi Horikoshi
Keyword(s):  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Synthetic Methods ◽  
Quantum Yields ◽  
Protective Agent ◽  
The Novel ◽  
Microwave Chemistry ◽  
High Quantum ◽  
Surface Modified ◽  
The Relationship

Since the first serendipity of carbon quantum dots (CQDs)1, it is expected to be used for imaging materials for reusable living bodies (e.g. Hela cells). However, the reported CQDs synthetic methods have yet to be at the practical levels; the quantum yields is low, and synthetic condition is over 5 hrs under more than 30 atms. In this research, we ameliorated the problems of CQDs synthesis and luminescence (quantum yields) by the novel synthesis protocol using microwave chemistry. Specifically, we synthesized high quantum yields CQDs (61%) by utilizing a microwave chemical synthesis, synthesizing at low pressure condition (lower than 5 atom) and short reaction time (3 hrs). The achievement of this high quantum yields made it clear that the contribution of polyethylene glycol (PEG) shell to CQDs is large. It was confirmed from the DLS and TEM image that the particle size of the synthesized particles was 8 to 13 nm (Fig. 1). On the other hand, the relationship between the polymerization degree of added PEG and the quantum yields to the addition amount is summarized in Table 1. The quantum yields of CQDs without addition of PEG was 16.7 %, while it was improved at 61.1 % when 0.6 g of PEG6000 (Molecular weight: 6000) was added.We succeeded in remarkably improving the quantum yields by using PEG, which is usually used as a protective agent, as a shell. By using this method, we succeeded in improving the quantum yields of the existing report by approximately 3 times. From the surface modified structure of PEG, the mechanism of improvement of quantum yields will be considered.[1] X. Xu et al., J. Am. Chem. Soc., 2004, 126, 12736–12737. 

scholarly journals The importance of surface states in N-doped Carbon Quantum Dots

Carbon ◽  
2021 ◽  
Author(s):  
Slavia Deeksha Dsouza ◽  
Marius Buerkle ◽  
Paul Brunet ◽  
Chiranjeevi Maddi ◽  
Dilli Babu Padmanaban ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Surface States ◽  
Carbon Quantum Dots

scholarly journals Recent Developments in Carbon Quantum Dots: Properties, Fabrication Techniques, and Bio-Applications

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 388
Author(s):  
Rehan M. El-Shabasy ◽  
Mohamed Farouk Elsadek ◽  
Badreldin Mohamed Ahmed ◽  
Mohamed Fawzy Farahat ◽  
Khaled N. Mosleh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Green Synthesis ◽  
Graphene Quantum Dots ◽  
Carbon Sources ◽  
Carbon Quantum Dots ◽  
Synthesis Methods ◽  
Wide Range ◽  
Recent Developments ◽  
Potential Applications ◽  
Harsh Conditions

Carbon dots have gained tremendous interest attributable to their unique features. Two approaches are involved in the fabrication of quantum dots (Top-down and Bottom-up). Most of the synthesis methods are usually multistep, required harsh conditions, and costly carbon sources that may have a toxic effect, therefore green synthesis is more preferable. Herein, the current review presents the green synthesis of carbon quantum dots (CQDs) and graphene quantum dots (GQDs) that having a wide range of potential applications in bio-sensing, cellular imaging, and drug delivery. However, some drawbacks and limitations are still unclear. Other biomedical and biotechnological applications are also highlighted.

scholarly journals The effect of oxygen on the microwave-assisted synthesis of carbon quantum dots from polyethylene glycol

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16637-16643 ◽  
Author(s):  
Yunyang Zhao ◽  
Songlin Zuo ◽  
Meng Miao
Keyword(s):  
Carbon Dioxide ◽  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Carbon Source ◽  
Microwave Irradiation ◽  
Carbon Quantum Dots ◽  
Microwave Assisted Synthesis ◽  
Microwave Irradiation Method ◽  
Microwave Assisted ◽  
Effect Of Oxygen

Fluorescent carbon quantum dots (CQDs) were synthesized using polyethylene glycol (PEG) as both the carbon source and solvent in various atmospheres including air, nitrogen, carbon dioxide and oxygen by following a microwave irradiation method.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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