scholarly journals Effect of Solvent on Fluorescence Emission from Polyethylene Glycol-Coated Graphene Quantum Dots under Blue Light Illumination

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1383
Author(s):  
Po-Chih Yang ◽  
Yu-Xuan Ting ◽  
Siyong Gu ◽  
Yasser Ashraf Gandomi ◽  
Jianlin Li ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Quantum Yield ◽  
Blue Light ◽  
Graphene Quantum Dots ◽  
Carbon Sources ◽  
Fluorescence Emission ◽  
Critical Index ◽  
Light Illumination ◽  
Hydrothermal Route ◽  
One Pot

To explore aggregate-induced emission (AIE) properties, this study adopts a one-pot hydrothermal route for synthesizing polyethylene glycol (PEG)-coated graphene quantum dot (GQD) clusters, enabling the emission of highly intense photoluminescence under blue light illumination. The hydrothermal synthesis was performed at 300 °C using o-phenylenediamine as the nitrogen and carbon sources in the presence of PEG. Three different solvents, propylene glycol methyl ether acetate (PGMEA), ethanol, and water, were used for dispersing the PEG-coated GQDs, where extremely high fluorescent emission was achieved at 530–550 nm. It was shown that the quantum yield (QY) of PEG-coated GQD suspensions is strongly dependent on the solvent type. The pristine GQD suspension tends to be quenched (i.e., QY: ~1%) when dispersed in PGMEA (aggregation-caused quenching). However, coating GQD nanoparticles with polyethylene glycol results in substantial enhancement of the quantum yield. When investigating the photoluminescence emission from PEG-coated GQD clusters, the surface tension of the solvents was within the range of from 26.9 to 46.0 mN/m. This critical index can be tuned for assessing the transition point needed to activate the AIE mechanism which ultimately boosts the fluorescence intensity. The one-pot hydrothermal route established in this study can be adopted to engineer PEG-coated GQD clusters with solid-state PL emission capabilities, which are needed for next-generation optical, bio-sensing, and energy storage/conversion devices.

Facile one-pot synthesis of long-term thermally stable CDs@AlOOH toward white-light illumination

2019 ◽  
Vol 7 (46) ◽  
pp. 14717-14724 ◽  
Author(s):  
Jiaming Wu ◽  
Shuxian Wang ◽  
Shuxin Liu ◽  
Shuwei Ma ◽  
Guojian Jing ◽  
...  
Keyword(s):  
Thermal Stability ◽  
White Light ◽  
Low Cost ◽  
Fluorescence Emission ◽  
Light Illumination ◽  
One Pot ◽  
One Pot Synthesis ◽  
One Step ◽  
White Light Illumination

The CDs doped boehmite composite (CDs@AlOOH) is directly achieved through a facile, low-cost and green one-step decomposition route with tunable fluorescence emission and long-term thermal stability.

Sustainable synthesis of single crystalline sulphur-doped graphene quantum dots for bioimaging and beyond

2018 ◽  
Vol 20 (18) ◽  
pp. 4245-4259 ◽  
Author(s):  
Sujata Sangam ◽  
Apoorv Gupta ◽  
Adeeba Shakeel ◽  
Rohan Bhattacharya ◽  
Arun Kumar Sharma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Graphene Quantum Dots ◽  
Hydrothermal Route ◽  
Single Crystalline ◽  
Doped Graphene

Waste-driven single crystalline sulphur-doped GQDs are synthesized via a green hydrothermal route with the highest quantum yield and excellent biocompatibility for bioimaging.

scholarly journals Highly Fluorescent Nitrogen-Doped Graphene Quantum Dots’ Synthesis and Their Applications as Fe(III) Ions Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Fei Lu ◽  
Yi-hua Zhou ◽  
Li-hui Wu ◽  
Jun Qian ◽  
Sheng Cao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Quantum Dots ◽  
Metal Ion ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Blue Fluorescence ◽  
One Pot ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-doped graphene quantum dots (N-GQDs) with strong blue fluorescence and a high quantum yield of 88.9% were synthesized via a facile one-pot hydrothermal treatment with citric acid (CA) and ethylenediamine (EDA) as carbon and nitrogen sources, respectively. The blue fluorescence emission is independent of the excitation wavelengths. These N-GQDs dispersed well in water and ethyl alcohol and showed a highly selective and sensitive detection of hazardous and toxic Fe3+in the range of 1600μmol/L to 6000μmol/L through a fluorescence quenching process with a detection limit of 2.37μmol/L. Based on the excellent sensitivity and selectivity of N-GQDs to heavy metal ions, paper-based sensors can be fabricated by inkjet printing, which are rapid but low cost. So the visual instant on-site identification of heavy metal ion will be realized in the future.

scholarly journals Quantum Yield Enhancement in Graphene Quantum Dots via Esterification with Benzyl Alcohol

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suzuka Tachi ◽  
Hiroki Morita ◽  
Misaki Takahashi ◽  
Yusuke Okabayashi ◽  
Takuya Hosokai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Benzyl Alcohol ◽  
Functional Groups ◽  
Photophysical Properties ◽  
Graphene Quantum Dots ◽  
Yield Enhancement ◽  
Light Illumination ◽  
Nonradiative Recombination ◽  
Widespread Application

Abstract The quantum yield of graphene quantum dots was enhanced by restriction of the rotation and vibration of surface functional groups on the edges of the graphene quantum dots via esterification with benzyl alcohol; this enhancement is crucial for the widespread application of graphene quantum dots in light-harvesting devices and optoelectronics. The obtained graphene quantum dots with highly graphene-stacked structures are understood to participate in π–π interactions with adjacent aromatic rings of the benzylic ester on the edges of the graphene quantum dots, thus impeding the nonradiative recombination process in graphene quantum dots. Furthermore, the crude graphene quantum dots were in a gel-like solid form and showed white luminescence under blue light illumination. Our results show the potential for improving the photophysical properties of nanomaterials, such as the quantum yield and band-gap energy for emission, by controlling the functional groups on the surface of graphene quantum dots through an organic modification approach.

Highly luminescent aggregate-induced emission from polyethylene glycol-coated carbon quantum dot clusters under blue light illumination

2020 ◽  
Vol 8 (46) ◽  
pp. 16569-16576
Author(s):  
Ruey-Shin Juang ◽  
Chun-Chieh Fu ◽  
Chien-Te Hsieh ◽  
Siyong Gu ◽  
Yasser Ashraf Gandomi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Quantum Dot ◽  
Blue Light ◽  
Carbon Quantum Dots ◽  
Light Illumination ◽  
Carbon Quantum Dot ◽  
Fluorescent Nanomaterials ◽  
Coated Carbon

Carbon quantum dots (CQDs) have been considered as one of the most promising fluorescent nanomaterials.

scholarly journals Red-light excitation of protoporphyrin IX fluorescence for subsurface tumor detection

2018 ◽  
Vol 128 (6) ◽  
pp. 1690-1697 ◽  
Author(s):  
David W. Roberts ◽  
Jonathan D. Olson ◽  
Linton T. Evans ◽  
Kolbein K. Kolste ◽  
Stephen C. Kanick ◽  
...  
Keyword(s):  
Blue Light ◽  
Aminolevulinic Acid ◽  
Red Light ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Low Grade ◽  
Light Illumination ◽  
Wide Field ◽  
Light Excitation ◽  
Surgical Field

OBJECTIVEThe objective of this study was to detect 5-aminolevulinic acid (ALA)-induced tumor fluorescence from glioma below the surface of the surgical field by using red-light illumination.METHODSTo overcome the shallow tissue penetration of blue light, which maximally excites the ALA-induced fluorophore protoporphyrin IX (PpIX) but is also strongly absorbed by hemoglobin and oxyhemoglobin, a system was developed to illuminate the surgical field with red light (620–640 nm) matching a secondary, smaller absorption peak of PpIX and detecting the fluorescence emission through a 650-nm longpass filter. This wide-field spectroscopic imaging system was used in conjunction with conventional blue-light fluorescence for comparison in 29 patients undergoing craniotomy for resection of high-grade glioma, low-grade glioma, meningioma, or metastasis.RESULTSAlthough, as expected, red-light excitation is less sensitive to PpIX in exposed tumor, it did reveal tumor at a depth up to 5 mm below the resection bed in 22 of 24 patients who also exhibited PpIX fluorescence under blue-light excitation during the course of surgery.CONCLUSIONSRed-light excitation of tumor-associated PpIX fluorescence below the surface of the surgical field can be achieved intraoperatively and enables detection of subsurface tumor that is not visualized under conventional blue-light excitation.Clinical trial registration no.: NCT02191488 (clinicaltrials.gov)

Highly fluorescent green and red emissions from boron-doped graphene quantum dots under blue light illumination

Carbon ◽  
2021 ◽  
Vol 176 ◽  
pp. 61-70
Author(s):  
Ruey-Shin Juang ◽  
Chien-Te Hsieh ◽  
Chih-Peng Kao ◽  
Yasser Ashraf Gandomi ◽  
Chun-Chieh Fu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Blue Light ◽  
Graphene Quantum Dots ◽  
Light Illumination ◽  
Boron Doped ◽  
Doped Graphene

A Simple Approach to the One-Pot Three Component Synthesis of 4Hpyrimido [2,1-b] benzothiazole Derivatives Using Polyethylene Glycol (PEG-400)

2015 ◽  
Vol 12 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Prabhakar Rairala ◽  
Bandi Yadagiri ◽  
Rajashaker Bantu ◽  
Vijayacharan Guguloth ◽  
Lingaiah Nagarapu
Keyword(s):  
Polyethylene Glycol ◽  
Simple Approach ◽  
One Pot ◽  
Benzothiazole Derivatives ◽  
Peg 400 ◽  
The One

scholarly journals Light as a Novel Inhibitor of Nitrite-Oxidizing Bacteria (NOB) for the Mainstream Partial Nitrification of Wastewater Treatment

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 346
Author(s):  
Keugtae Kim ◽  
Yong-Gyun Park
Keyword(s):  
Wastewater Treatment ◽  
Blue Light ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Partial Nitrification ◽  
Biological Nutrient Removal ◽  
Nitrite Accumulation ◽  
Light Illumination ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrite Oxidizing Bacteria

Conventional biological nutrient removal processes in municipal wastewater treatment plants are energy-consuming, with oxygen supply accounting for 45–75% of the energy expenditure. Many recent studies examined the implications of the anammox process in sidestream wastewater treatment to reduce energy consumption, however, the process did not successfully remove nitrogen in mainstream wastewater treatment with relatively low ammonia concentrations. In this study, blue light was applied as an inhibitor of nitrite-oxidizing bacteria (NOB) in a photo sequencing batch reactor (PSBR) containing raw wastewater. This simulated a biological nitrogen removal system for the investigation of its application potential in nitrite accumulation and nitrogen removal. It was found that blue light illumination effectively inhibited NOB rather than ammonia-oxidizing bacteria due to their different sensitivity to light, resulting in partial nitrification. It was also observed that the NOB inhibition rates were affected by other operational parameters like mixed liquor suspended solids (MLSS) concentration and sludge retention time (SRT). According to the obtained results, it was concluded that the process efficiency of partial nitrification and anammox (PN/A) could be significantly enhanced by blue light illumination with appropriate MLSS concentration and SRT conditions.

A facile synthetic protocol of α-Fe2O3@FeS2 nanocrystals for advanced electrochemical capacitors

CrystEngComm ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 2432-2438 ◽  
Author(s):  
Qing Xia ◽  
Tong Xia ◽  
Meizhen Dai ◽  
Xiang Wu ◽  
Yufeng Zhao
Keyword(s):  
Charge Transfer ◽  
Electrode Material ◽  
Electrochemical Capacitors ◽  
Cyclic Stability ◽  
Hydrothermal Route ◽  
One Pot

In this work, we report granular α-Fe2O3@FeS2 nanocrystals by a one-pot hydrothermal route. The as-obtained product as an electrode material shows excellent charge transfer ability and cyclic stability.

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