Graphene quantum dots coated on quartz sand as efficient and low-cost adsorbent for removal of Hg2+ and Pb2+ from aqueous solutions

2018 ◽  
Vol 38 (s1) ◽  
pp. S24-S31 ◽  
Author(s):  
Rahim Mohammad-Rezaei ◽  
Mehdi Jaymand
Keyword(s):  
Quantum Dots ◽  
Aqueous Solutions ◽  
Quartz Sand ◽  
Low Cost ◽  
Graphene Quantum Dots

scholarly journals High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aumber Abbas ◽  
Tanveer A. Tabish ◽  
Steve J. Bull ◽  
Tuti Mariana Lim ◽  
Anh N. Phan
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Cost Effective ◽  
Renewable Resource ◽  
Microwave Treatment ◽  
High Yield ◽  
Biomass Waste ◽  
Practical Applications

AbstractGraphene quantum dots (GQDs), a novel type of zero-dimensional fluorescent materials, have gained considerable attention owing to their unique optical properties, size and quantum confinement. However, their high cost and low yield remain open challenges for practical applications. In this work, a low cost, green and renewable biomass resource is utilised for the high yield synthesis of GQDs via microwave treatment. The synthesis approach involves oxidative cutting of short range ordered carbon derived from pyrolysis of biomass waste. The GQDs are successfully synthesised with a high yield of over 84%, the highest value reported to date for biomass derived GQDs. As prepared GQDs are highly hydrophilic and exhibit unique excitation independent photoluminescence emission, attributed to their single-emission fluorescence centre. As prepared GQDs are further modified by simple hydrothermal treatment and exhibit pronounced optical properties with a high quantum yield of 0.23. These modified GQDs are used for the highly selective and sensitive sensing of ferric ions (Fe3+). A sensitive sensor is prepared for the selective detection of Fe3+ ions with a detection limit of as low as 2.5 × 10–6 M. The utilisation of renewable resource along with facile microwave treatment paves the way to sustainable, high yield and cost-effective synthesis of GQDs for practical applications.

scholarly journals Graphene Quantum Dots Open Up New Prospects for Interfacial Modifying in Graphene/Silicon Schottky Barrier Solar Cell

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chao Geng ◽  
Xiuhua Chen ◽  
Shaoyuan Li ◽  
Zhao Ding ◽  
Wenhui Ma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Schottky Barrier ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Separation Processes ◽  
Band Bending ◽  
Carrier Recombination ◽  
Photovoltaic Applications ◽  
Graphene Oxide Quantum Dots

Graphene/silicon (Gr/Si) Schottky barrier solar cells (SBSCs) are attractive for harvesting solar energy and have been gaining grounds for its low-cost solution-processing. The interfacial barrier between graphene and silicon facilitates the reducing excessive carrier recombination while accelerating the separation processes of photo-generated carriers at the interface, which empowers the performance of Gr/Si SBSCs. However, the difficulty to control the interface thickness prevents its application. Here, we introduce the graphene oxide quantum dots (GOQDs) as a unique interfacial modulation species with tunable thickness by controlling the GOQDs particle size. The power conversion efficiency (PCE) of 13.67% for Gr/Si-based SBSC with outstanding stability in the air is obtained with the optimal barrier thickness (26 nm) and particle size (4.15 nm) of GOQDs. The GOQDs in Gr/Si-based SBSCs provide the extra band bending which further enhances the PCE for its photovoltaic applications.

Graphene quantum dots as a novel sensing material for low-cost resistive and fast-response humidity sensors

2015 ◽  
Vol 218 ◽  
pp. 73-77 ◽  
Author(s):  
Virginia Ruiz ◽  
Iván Fernández ◽  
Pedro Carrasco ◽  
Germán Cabañero ◽  
Hans J. Grande ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Fast Response ◽  
Humidity Sensors ◽  
Sensing Material

Glucose sensing via a green and low-cost platform from electrospun poly (vinyl alcohol)/graphene quantum dots fibers

2019 ◽  
Vol 14 ◽  
pp. 694-699
Author(s):  
Tayna S. Cabral ◽  
Livia F. Sgobbi ◽  
Jorge Delezuk ◽  
Rodrigo S. Pessoa ◽  
Anderson O. Lobo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Vinyl Alcohol ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Glucose Sensing ◽  
Poly Vinyl Alcohol

scholarly journals Understanding of Catalytic ROS Generation From Defect-Rich Graphene Quantum-Dots for Therapeutic Effects in Tumor Microenvironment

2021 ◽  
Author(s):  
Xichu Wang ◽  
Chuangang Hu ◽  
Zi (Sophia) Gu ◽  
Liming Dai
Keyword(s):  
Quantum Dots ◽  
Tumor Microenvironment ◽  
Catalytic Mechanism ◽  
Defect Density ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
Ros Generation ◽  
Therapeutic Effects

Abstract Owing to their low cost, high catalytic efficiency and biocompatibility, carbon-based metalfree catalysts (C-MFCs) have attracted intense interest for various applications, ranging from energy through environmental to biomedical technologies. While considerable efforts and progress have been made in mechanistic understanding of C-MFCs for non-biomedical applications, their catalytic mechanism for therapeutic effects has rarely been investigated. In this study, defect-rich graphene quantum dots (GQDs) were developed as C-MFCs for efficient ROS generation, specifically in the H2O2 -rich tumor microenvironment to cause multi-level damage of subcellular components (even in nuclei). While a desirable anti-cancer performance was achieved, the catalytic performance was found to strongly depend on the defect density. It is for the first time that the defect-induced catalytic generation of ROS by C-MFCs in the tumor microenvironment was demonstrated and the associated catalytic mechanism was elucidated. This work opens a new avenue for the development of safe and efficient catalytic nanomedicine.

Detection of Escherichia coli O157:H7 with Antibody Conjugated Amino-Functionalized Graphene Quantum Dots as Immunofluorescence Probes

2019 ◽  
Vol 807 ◽  
pp. 151-158
Author(s):  
Xiao Zhan Yang ◽  
Wen Lin Feng ◽  
Gao Chen ◽  
Hong Feng Guo ◽  
Dao Yuan Wang
Keyword(s):  
Escherichia Coli ◽  
Quantum Dots ◽  
Pathogen Detection ◽  
Low Cost ◽  
Graphene Quantum Dots ◽  
Spectroscopic Properties ◽  
Spectroscopic Techniques ◽  
Functionalized Graphene ◽  
Raman Spectroscopic ◽  
E Coli

Escherichia coli O157: H7 (E. coli O157: H7) is a foodborne pathogenic bacterium which can cause fever, diarrhoea and vomiting in humans. Thus, a rapid, simple, and specific bioprobe for pathogen detection in contaminated foods has been attracted more and more attention. In this work, the strong fluorescent amino-functionalized graphene quantum dots (af-GQDs) were prepared by hydrothermal method. The microtopographic height, surface morphology and spectroscopic properties of af-GQDs are characterized by the high resolution transmission electron microscope (HRTEM), atomic force microscope (AFM), UV-vis, fluorescence, Raman spectroscopic techniques. All the results showed that the af-GQDs can be effectively applied in the preparation of biocompatible immunofluorescence probe and in the detection of E. coli O157: H7. The minimum detection limit is 100 cfu/mL. It is a simple, rapid, sensitive, low-cost and easy to be popularized method, which provides a feasible way to monitor E. coli O157: H7 in food safety.

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