Photoluminescence Properties Research on Graphene Quantum Dots/Silver Composites

2016 ◽  
Vol 16 (4) ◽  
pp. 3480-3488
Author(s):  
Jun Wang ◽  
Yan Li ◽  
Bo-Ping Zhang ◽  
Dan-Dan Xie ◽  
Juan Ge ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Metal Ions ◽  
Chemical Method ◽  
Graphene Quantum Dots ◽  
Physical Method ◽  
Peak Position ◽  
Great Promise ◽  
Excitation Wavelength ◽  
Silver Composites ◽  
Physical And Chemical

Graphene quantum dots (GQDs) possess unique properties of graphene and exhibit a series of new phenomena of 0 dimension (D) carbon materials. Thus, GQDs have attracted much attention from researchers and have shown great promise for many applications. Recently, many works focus on GQDs-metal ions and metal nanoparticles (NPs). Although, many researches point out that metal ions and metal NPs have significant effect on photoluminescence (PL) feature of GQDs, mainly focus on PL intensity. Here, for the first time, we reported that metal NPs also affected PL peak position which was dependent on the mix mechanism of metal and GQDs. When GQDs-silver (Ag) composite mixed by physical method and excited at a wavelength of 320 nm, PL peak position of composites first showed blue-shifted then red-shifted with increasing of Ag content. However, if GQDs-Ag composite prepared by chemical method, PL peak position of the composites blue-shifted. Furthermore, the shift of PL peak position of GQDs-Ag prepared both for physical and chemical method displayed excitation-dependent feature. When the excitation wavelength approached to Ag SPR peaks, no obvious PL shift was observed. The mechanism for different PL shifts and the phenomenon of excitation-dependent PL shift as well as the formation mechanism of GQDs-Ag composite by chemical method are discussed in detail in this paper.

scholarly journals Chlorine Modulation Fluorescent Performance of Seaweed-Derived Graphene Quantum Dots for Long-Wavelength Excitation Cell-Imaging Application

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4994
Author(s):  
Weitao Li ◽  
Ningjia Jiang ◽  
Bin Wu ◽  
Yuan Liu ◽  
Luoman Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cell Imaging ◽  
Graphene Quantum Dots ◽  
Toxic Metal ◽  
Disease Diagnosis ◽  
Excitation Wavelength ◽  
Chlorine Atoms ◽  
Long Wavelength ◽  
Imaging Application ◽  
Preliminary Application

Biological imaging is an essential means of disease diagnosis. However, semiconductor quantum dots that are used in bioimaging applications comprise toxic metal elements that are nonbiodegradable, causing serious environmental problems. Herein, we developed a novel ecofriendly solvothermal method that uses ethanol as a solvent and doping with chlorine atoms to prepare highly fluorescent graphene quantum dots (GQDs) from seaweed. The GQDs doped with chlorine atoms exhibit high-intensity white fluorescence. Thus, their preliminary application in bioimaging has been confirmed. In addition, clear cell imaging could be performed at an excitation wavelength of 633 nm.

Nanomolar Level Detection of Metal Ions by Improving the Monodispersity and Stability of Nitrogen-Doped Graphene Quantum Dots

2021 ◽  
Author(s):  
Neeraj Sohal ◽  
Simran Kaur Bhatia ◽  
Soumen Basu ◽  
Banibrata Maity
Keyword(s):  
Quantum Dots ◽  
Metal Ions ◽  
Fluorescent Sensor ◽  
Graphene Quantum Dots ◽  
Intrinsic Properties ◽  
Heteroatom Doping ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Heteroatom doping of graphene quantum dots (GQDs) leads to modify their intrinsic properties and used as a fluorescent sensor for the metal ions sensing. Here, Nitrogen-doped GQDs (N-GQDs) was synthesized...

Multiplexed Graphene Quantum Dots with Excitation-Wavelength-Independent Photoluminescence, as Two-Photon Probes, and in Ultraviolet–Near Infrared Bioimaging

ACS Nano ◽  
2020 ◽  
Vol 14 (9) ◽  
pp. 11502-11509
Author(s):  
Wen-Shuo Kuo ◽  
Xing-Can Shen ◽  
Chia-Yuan Chang ◽  
Hui-Fang Kao ◽  
Sheng-Han Lin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Infrared ◽  
Graphene Quantum Dots ◽  
Excitation Wavelength ◽  
Two Photon

scholarly journals Investigating the Properties of Cetyltrimethylammonium Bromide/Hydroxylated Graphene Quantum Dots Thin Film for Potential Optical Detection of Heavy Metal Ions

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2591 ◽  
Author(s):  
Nur Ain Asyiqin Anas ◽  
Yap Wing Fen ◽  
Nor Azah Yusof ◽  
Nur Alia Sheh Omar ◽  
Nur Syahira Md Ramdzan ◽  
...  
Keyword(s):  
Thin Film ◽  
Heavy Metal ◽  
Quantum Dots ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Cetyltrimethylammonium Bromide ◽  
Graphene Quantum Dots ◽  
Atomic Force ◽  
The Fourier Transform ◽  
High Absorption

The modification of graphene quantum dots (GQDs) may drastically enhance their properties, therefore resulting in various related applications. This paper reported the preparation of novel cetyltrimethylammonium bromide/hydroxylated graphene quantum dots (CTAB/HGQDs) thin film using the spin coating technique. The properties of the thin film were then investigated and studied. The functional groups existing in CTAB/HGQDs thin film were confirmed by the Fourier transform infrared (FTIR) spectroscopy, while the atomic force microscope (AFM) displayed a homogenous surface of the thin film with an increase in surface roughness upon modification. Optical characterizations using UV-Vis absorption spectroscopy revealed a high absorption with an optical band gap of 4.162 eV. Additionally, the photoluminescence (PL) spectra illustrated the maximum emission peak of CTAB/HGQDs thin film at a wavelength of 444 nm. The sensing properties of the as-prepared CTAB/HGQDs thin film were studied using a surface plasmon resonance technique towards the detection of several heavy metal ions (HMIs) (Zn2+, Ni2+, and Fe3+). This technique generated significant results and showed that CTAB/HGQDs thin film has great potential for HMIs detection.

scholarly journals Efficient Degradation of High-Molecular-Weight Hyaluronic Acid by a Combination of Ultrasound, Hydrogen Peroxide, and Copper Ion

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 617 ◽  
Author(s):  
Hongyue Chen ◽  
Jing Qin ◽  
Yi Hu
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Hyaluronic Acid ◽  
High Molecular Weight ◽  
Chemical Method ◽  
Copper Ion ◽  
Physical Method ◽  
Cd Spectroscopy ◽  
Low Molecular Weight ◽  
Physical And Chemical

Hyaluronic acid (HA) was depolymerized by a combination of ultrasound, hydrogen peroxide and copper ion. The structures of high-molecular-weight hyaluronic acid (HMW-HA) and low-molecular-weight hyaluronic acid (LMW-HA) were determined by Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) spectroscopy, and UV-VIS absorption spectroscopy. The degradations of HMW-HA using a physical method, a chemical method, and a combination of physical and chemical method were compared. The results show that HA can be effectively degraded by a combinatorial method involving ultrasound, hydrogen peroxide, and copper ion. Under the degradation conditions of 50 mM H2O2, 5.0 μM CuCl2, 160 W, pH 4.0, and reaction at 50 °C for 30 min, the content of glucuronic acid was 36.56%, and the yield of LMW-HA was 81.71%. The FTIR, CD, and UV-VIS absorption spectra of HA did not change with the decrease in molecular weight, indicating that the structure of HA remained intact during the degradation.

scholarly journals Cane Molasses Graphene Quantum Dots Passivated by PEG Functionalization for Detection of Metal Ions

ACS Omega ◽  
2020 ◽  
Vol 5 (12) ◽  
pp. 6763-6772 ◽  
Author(s):  
Ying Lou ◽  
Jianying Ji ◽  
Aimiao Qin ◽  
Lei Liao ◽  
Ziyuan Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Metal Ions ◽  
Graphene Quantum Dots ◽  
Cane Molasses ◽  
Peg Functionalization

scholarly journals Ultra-narrow-bandwidth graphene quantum dots for superresolved spectral and spatial sensing

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhen Wang ◽  
Xuezhe Dong ◽  
Shuyun Zhou ◽  
Zheng Xie ◽  
Zeev Zalevsky
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Spatial Separation ◽  
Wavelength Dependence ◽  
Excitation Wavelength ◽  
Step Method ◽  
Environmental Friendliness ◽  
Narrow Bandwidth ◽  
Spectroscopic Information ◽  
New Generation

AbstractNarrow-bandwidth luminescent materials are already used in optoelectronic devices, superresolution, lasers, imaging, and sensing. The new-generation carbon fluorescence nanomaterials—carbon dots—have attracted considerable attention due to their advantages, such as simple operation, environmental friendliness, and good photoelectric performance. In this work, two narrower-bandwidth (21 and 30 nm) emission graphene quantum dots with long-wavelength fluorescence were successfully prepared by a one-step method, and their photoluminescence (PL) peaks were at 683 and 667 nm, respectively. These red-emitting graphene quantum dots were characterized by excitation wavelength dependence of the fluorescence lifetimes, and they were successfully applied to spectral and spatial superresolved sensing. Here, we proposed to develop an infrared spectroscopic sensing configuration based on two narrow-bandwidth-emission graphene quantum dots. The advantage of the method used is that spectroscopic information was extracted without using a spectrometer, and two narrow-bandwidth-emission graphene quantum dots were simultaneously excited to achieve spatial separation through the unique temporal “signatures” of the two types of graphene quantum dots. The spatial separation localization errors of the graphene quantum dots (GQDs-Sn and GQDs-OH) were 1 pixel (10 nm) and 3 pixels (30 nm), respectively. The method could also be adjusted for nanoscope-related applications in which spatial superresolved sensing was achieved.

Green, simple and large scale synthesis of N-doped graphene quantum dots with uniform edge groups by electrochemical bottom-up synthesis

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 82648-82653 ◽  
Author(s):  
Linfan Tian ◽  
Siwei Yang ◽  
Yucheng Yang ◽  
Jipeng Li ◽  
Yuan Deng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Large Scale ◽  
Graphene Quantum Dots ◽  
Excitation Wavelength ◽  
Bottom Up ◽  
Edge Group ◽  
Doped Graphene ◽  
Large Scale Synthesis ◽  
First Time

An electrochemical bottom-up synthesis of N-doped GQDs (N-GQDs) with large amount of well-defined edge groups was developed for the first time. The exclusive edge group of the obtained N-GQDs is –NH2 results in the excitation wavelength independence behavior.

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