scholarly journals Evaluation of Commercial “Carbon Quantum Dots” Sample on Origins of Red Absorption and Emission Features

2019 ◽  
Vol 5 (4) ◽  
pp. 70 ◽  
Author(s):  
Liang ◽  
Ge ◽  
Hou ◽  
Ren ◽  
Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Carbon Nanoparticles ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Research Field ◽  
One Pot ◽  
Commercial Sample ◽  
Carbon Particles ◽  
Negative Impacts

The commercially acquired aqueous solution of “carbon quantum dots” sample was evaluated by optical absorption and fluorescence emission methods; in reference to aqueous dispersed small carbon nanoparticles and representative carbon dots prepared from chemical functionalization of the carbon nanoparticles. The results suggest a very low content of carbon that is associated with nanoscale carbon particles/domains in the as-supplied sample; and likely significant contamination by dye-like species/mixtures. In the absence of any information on the synthesis and history of the commercial sample, the possible cause of the contamination was illustrated by an example on similar dye formation in the one-pot carbonization synthesis of “red carbon dots” from citric acid–formamide precursor mixtures under too mild processing conditions that were insufficient for the intended carbonization. The negative impacts to the carbon dots research field by the apparent proliferation and now commercial availability of carbon-deficient or even largely carbon-less “carbon quantum dots”, which are more susceptible to dye contamination or dominance, are discussed.

A green synthetic route for the surface-passivation of carbon dots as an effective multifunctional fluorescent sensor for the recognition and detection of toxic metal ions from aqueous solution

2019 ◽  
Vol 11 (4) ◽  
pp. 490-506 ◽  
Author(s):  
K. Radhakrishnan ◽  
P. Panneerselvam ◽  
M. Marieeswaran
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Carbon Dots ◽  
Surface Passivation ◽  
Fluorescent Sensor ◽  
Toxic Metal ◽  
Carbon Quantum Dots ◽  
Synthetic Route ◽  
One Pot ◽  
Hydrothermal Methods

In this work, a green synthetic route was used to create a number of surface passivated fluorescent carbon quantum dots, which are explored as promising sensing probes, via facile one-pot hydrothermal methods.

scholarly journals Carbon Dots for Sensing and Killing Microorganisms

2019 ◽  
Vol 5 (2) ◽  
pp. 33 ◽  
Author(s):  
Fengming Lin ◽  
Yan-Wen Bao ◽  
Fu-Gen Wu
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Carbon Nanoparticles ◽  
Surface Passivation ◽  
Electronic Devices ◽  
Carbon Quantum Dots ◽  
Toxicity Profile ◽  
Carbon Dot ◽  
Underlying Mechanisms

Carbon dots (or carbon quantum dots) are small (less than 10 nm) and luminescent carbon nanoparticles with some form of surface passivation. As an emerging class of nanomaterials, carbon dots have found wide applications in medicine, bioimaging, sensing, electronic devices, and catalysis. In this review, we focus on the recent advancements of carbon dots for sensing and killing microorganisms, including bacteria, fungi, and viruses. Synthesis, functionalization, and a toxicity profile of these carbon dots are presented. We also discuss the underlying mechanisms of carbon dot-based sensing and killing of microorganisms.

scholarly journals Biomass-derived Carbon Quantum Dots for Visible-Light-Induced Photocatalysis and Label-Free Detection of Fe(III) and Ascorbic acid

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gouri Sankar Das ◽  
Jong Pil Shim ◽  
Amit Bhatnagar ◽  
Kumud Malika Tripathi ◽  
TaeYoung Kim
Keyword(s):  
Quantum Dots ◽  
Ascorbic Acid ◽  
Visible Light ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Active Species ◽  
Label Free ◽  
One Pot ◽  
Label Free Detection ◽  
Visible Light Driven

Abstract Visible-light-driven photocatalysts prepared using renewable resources are crucial but challenging to develop for the efficient degradation of organic pollutants, which is required to solve ever-increasing water deterioration issues. In this study, we report a visible-light-responsive photocatalyst for the efficient degradation of methylene blue (MB) as a model pollutant dye. Green-emissive carbon quantum dots (CQDs) were synthesized from pear juice via a facile, scalable, one-pot solvothermal process. The as-synthesized CQDs exhibit superior photocatalytic activity under visible-light irradiation owing to their efficient light absorption, electron transfer, and separation of photogenerated charge carriers, facilitating ~99.5% degradation of MB within 130 min. A possible mechanism for the photocatalysis is proposed on the basis of comprehensive active species trapping experiments. Furthermore, the CQDs were used in a specific sensitive assay for Fe(III) and ascorbic acid (AA), even with interference from other metal ions. The fluorescence emission of CQDs was “turned off” specifically upon binding of Fe(III) and “turned on” with AA. The prepared CQDs represent efficient photocatalysts and fluorescent probes that are not restricted by toxicity, cost, or lack of scalability.

scholarly journals A facile green and one-pot synthesis of grape seed-derived carbon quantum dots as a fluorescence probe for Cu(ii) and ascorbic acid

RSC Advances ◽  
2021 ◽  
Vol 11 (54) ◽  
pp. 34107-34116
Author(s):  
Jiawei Li ◽  
Ouwen Xu ◽  
Xiashi Zhu
Keyword(s):  
Quantum Dots ◽  
Ascorbic Acid ◽  
Carbon Dots ◽  
Fluorescence Probe ◽  
Grape Seed ◽  
Carbon Quantum Dots ◽  
One Pot ◽  
One Pot Synthesis ◽  
Doped Carbon Dots

In this study, an on–off–on fluorescence probe for the detection of trace Cu(ii) and ascorbic acid (AA) based on biomass-derived sulfur and nitrogen double heteroatom-doped carbon dots (N,S-CDs) was designed.

scholarly journals Role of alkan-1-ol solvents in the synthesis of yellow luminescent carbon quantum dots (CQDs): van der Waals force-caused aggregation and agglomeration

RSC Advances ◽  
2020 ◽  
Vol 10 (24) ◽  
pp. 14396-14402 ◽  
Author(s):  
Kenta Hagiwara ◽  
Hiroshi Uchida ◽  
Yumiko Suzuki ◽  
Takashi Hayashita ◽  
Kanjiro Torigoe ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nanoparticles ◽  
Van Der Waals ◽  
Carbon Quantum Dots ◽  
Van Der Waals Force

Carbon quantum dots (CQDs; luminescent carbon nanoparticles, size < 10 nm) have attracted much attention with respect to their eco-friendliness and multi-functionality.

FRET Study Between Carbon Quantum Dots and Malachite Green by Steady-State and Time-Resolved Fluorescence Spectroscopy

2020 ◽  
Vol 10 (3) ◽  
pp. 178-188
Author(s):  
Bipin Rooj ◽  
Ankita Dutta ◽  
Debojyoti Mukherjee ◽  
Sahidul Islam ◽  
Ujjwal Mandal
Keyword(s):  
Quantum Dots ◽  
Energy Transfer ◽  
Fluorescence Spectroscopy ◽  
Malachite Green ◽  
Dye Degradation ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Time Resolved Fluorescence ◽  
Physical Processes ◽  
Time Resolved

Background: Understanding the interaction between different organic dyes and carbon quantum dots helps us to understand several photo physical processes like electron transfer, energy transfer, molecular sensing, drug delivery and dye degradation processes etc. Objective: The primary objective of this study is to whether the carbon quantum dots can act as an electron donor and can participate in the different photo physical processes. Methods: In this work, Carbon Quantum Dots (CQDLs) are synthesized in most economical and simple carbonization method where petals of Nelumbo nucifera L. are used as a carbon precursor. The synthesized CQDLs were characterized by using experimental techniques like UV−Vis absorption, FT-IR, Transmission Electron Microscopy (TEM), steadystate and time-resolved fluorescence spectroscopy. Results: The spectral analysis shows that the so synthesized CQDLs are spherical in shape and its diameter is around 4.2 nm. It shows the fluorescence emission maximum at 495 nm with a quantum yield of 4%. In this work the interaction between Carbon Quantum Dots (CQDLs) and an organic dye Malachite Green (MG) is studied using fluorescence spectroscopic technique under ambient pH condition (At pH 7). The quenching mechanism of CQDLs with MG was investigated using Stern-Volmer equation and time-resolved fluorescence lifetime studies. The results show that the dominant process of fluorescence quenching is attributed to Forster Resonance Energy Transfer (FRET) having a donor acceptor distance of 53 Å where CQDLs act as a donor and MG acts as an acceptor. Conclusion: This work has a consequence that CQDLs can be used as a donor species for different photo physical processes such as photovoltaic cell, dye sensitized solar cell, and also for antioxidant activity study.

One-Pot Large-Scale Synthesis of Carbon Quantum Dots: Efficient Cathode Interlayers for Polymer Solar Cells

2017 ◽  
Vol 9 (17) ◽  
pp. 14953-14959 ◽  
Author(s):  
Yuzhao Yang ◽  
Xiaofeng Lin ◽  
Wenlang Li ◽  
Jiemei Ou ◽  
Zhongke Yuan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Large Scale ◽  
Polymer Solar Cells ◽  
Carbon Quantum Dots ◽  
One Pot ◽  
Large Scale Synthesis
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