Origin of green luminescence in carbon quantum dots: specific emission bands originate from oxidized carbon groups

2018 ◽  
Vol 42 (6) ◽  
pp. 4603-4611 ◽  
Author(s):  
Zhiguo Sun ◽  
Xiaoming Li ◽  
Ye Wu ◽  
Changting Wei ◽  
Haibo Zeng
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Surface State ◽  
Carbon Quantum Dots ◽  
Green Luminescence ◽  
Oxidized Carbon

This study demonstrates that the surface state functional groups are responsible for green waveband originating from CDs.

Extraction of Electrochemiluminescent Oxidized Carbon Quantum Dots from Activated Carbon

2010 ◽  
Vol 22 (21) ◽  
pp. 5895-5899 ◽  
Author(s):  
Yongqiang Dong ◽  
Nana Zhou ◽  
Xiaomei Lin ◽  
Jianpeng, Lin ◽  
Yuwu Chi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Activated Carbon ◽  
Carbon Quantum Dots ◽  
Oxidized Carbon

scholarly journals Synthesis and Properties of Nitrogen-Doped Carbon Quantum Dots Using Lactic Acid as Carbon Source

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 466
Author(s):  
Kaixin Chang ◽  
Qianjin Zhu ◽  
Liyan Qi ◽  
Mingwei Guo ◽  
Woming Gao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Lactic Acid ◽  
Fluorescence Quenching ◽  
Functional Groups ◽  
Fluorescence Intensity ◽  
Carbon Quantum Dots ◽  
Nitrogen Doped ◽  
Ph Values ◽  
Wide Range ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions.

scholarly journals Localized Surface Plasmon Resonance Decorated with Carbon Quantum Dots and Triangular Ag Nanoparticles for Chlorophyll Detection

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Nur Afifah Ahmad Nazri ◽  
Nur Hidayah Azeman ◽  
Mohd Hafiz Abu Bakar ◽  
Nadhratun Naiim Mobarak ◽  
Yunhan Luo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Surface Plasmon Resonance ◽  
Detection Limit ◽  
Functional Groups ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Linear Response ◽  
Localized Surface Plasmon Resonance ◽  
Carbon Quantum Dots ◽  
Localized Surface Plasmon

This paper demonstrates carbon quantum dots (CQDs) with triangular silver nanoparticles (AgNPs) as the sensing materials of localized surface plasmon resonance (LSPR) sensors for chlorophyll detection. The CQDs and AgNPs were prepared by a one-step hydrothermal process and a direct chemical reduction process, respectively. FTIR analysis shows that a CQD consists of NH2, OH, and COOH functional groups. The appearance of C=O and NH2 at 399.5 eV and 529.6 eV in XPS analysis indicates that functional groups are available for adsorption sites for chlorophyll interaction. A AgNP–CQD composite was coated on the glass slide surface using (3-aminopropyl) triethoxysilane (APTES) as a coupling agent and acted as the active sensing layer for chlorophyll detection. In LSPR sensing, the linear response detection for AgNP–CQD demonstrates R2 = 0.9581 and a sensitivity of 0.80 nm ppm−1, with a detection limit of 4.71 ppm ranging from 0.2 to 10.0 ppm. Meanwhile, a AgNP shows a linear response of R2 = 0.1541 and a sensitivity of 0.25 nm ppm−1, with the detection limit of 52.76 ppm upon exposure to chlorophyll. Based on these results, the AgNP–CQD composite shows a better linearity response and a higher sensitivity than bare AgNPs when exposed to chlorophyll, highlighting the potential of AgNP–CQD as a sensing material in this study.

A green luminescence of lemon derived carbon quantum dots and their applications for sensing of V5+ ions

2019 ◽  
Vol 251 ◽  
pp. 114455 ◽  
Author(s):  
Bui Thi Hoan ◽  
Tran Thi Thanh ◽  
Phuong Dinh Tam ◽  
Nguyen Ngoc Trung ◽  
Sunglae Cho ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
Green Luminescence

Electrochemical probing of carbon quantum dots: not suitable for a single electrode material

RSC Advances ◽  
2015 ◽  
Vol 5 (130) ◽  
pp. 107270-107275 ◽  
Author(s):  
Xinnan Jia ◽  
Xiaobo Ji
Keyword(s):  
Quantum Dots ◽  
Electrochemical Properties ◽  
Functional Groups ◽  
Electrode Material ◽  
Negative Impact ◽  
Carbon Quantum Dots ◽  
High Oxygen ◽  
Oxygen Functional Groups ◽  
Better Than

We demonstrate that the easy aggregation, rapid stacking and high oxygen-functional groups of GQDs have a negative impact on the electrochemical properties. GQDs are no better than graphene as an excellent single electrode material.

Synthesis of carbon quantum dots with green luminescence from potato starch

2019 ◽  
Vol 43 (27) ◽  
pp. 10826-10833 ◽  
Author(s):  
Ruibin Qiang ◽  
Shengrong Yang ◽  
Kaiming Hou ◽  
Jinqing Wang
Keyword(s):  
Quantum Dots ◽  
Potato Starch ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Raw Material ◽  
Carbon Precursor ◽  
Biomass Carbon ◽  
Green Luminescence ◽  
Soluble Carbon

Water-soluble carbon quantum dots (CQDs) are synthesized via an acid assisted ultrasonic route using the biomass carbon precursor of potato starch as the raw material.

scholarly journals Potential Application of Nitrogen-Doped Carbon Quantum Dots Synthesized by a Solvothermal Method for Detecting Silver Ions in Food Packaging

2019 ◽  
Vol 16 (14) ◽  
pp. 2518 ◽  
Author(s):  
Lu ◽  
Su ◽  
Feng ◽  
Jiang ◽  
Hong ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Food Packaging ◽  
Detection Method ◽  
Solvothermal Method ◽  
Carbon Quantum Dots ◽  
Average Lifetime ◽  
Nitrogen Doped ◽  
Flame Atomic Absorption ◽  
Nitrogen Doped Carbon

In this paper, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by a solvothermal method using 1,2,4-triaminobenzene as a carbon precursor. The surface of the synthesized N-CQDs was modified with amino functional groups. The results indicated that N-CQDs had various N-related functional groups and chemical bonds and were amorphous in structure. At the same time, the quantum yield of N-CQDs was 5.11%, and the average lifetime of fluorescence decay was 5.79 ns. The synthesized N-CQDs showed good selectivity for and sensitivity to Ag+. A linear relationship between N-CQDs detection efficiency and Ag+ concentration was observed for concentration ranges of Ag+ corresponding to 0–10 μM and 10–30 μM. In addition, N-CQDs were used for the detection of trace Ag+ in food packaging material. The silver ion content of the sample determined by the N-CQDs detection method was 1.442 mg/L, with a relative error of 6.24% with respect to flame atomic absorption spectrometry, according to which the Ag+ content was 1.352 mg/L. This indicates that the N-CQDs detection method is reliable. Therefore, the N-CQDs prepared in this paper can detect Ag+ rapidly, simply, and sensitively and are expected to be a promising tool for the detection of trace Ag+ in food packaging materials.

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