Highly-flexible and -stable deep-ultraviolet photodiodes made of graphene quantum dots sandwiched between graphene layers

2019 ◽  
Vol 163 ◽  
pp. 238-242 ◽  
Author(s):  
Chan Wook Jang ◽  
Dong Hee Shin ◽  
Suk-Ho Choi
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Graphene Layers ◽  
Deep Ultraviolet

scholarly journals Green Preparation of High Yield Fluorescent Graphene Quantum Dots from Coal-Tar-Pitch by Mild Oxidation

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 844 ◽  
Author(s):  
Quanrun Liu ◽  
Jingjie Zhang ◽  
He He ◽  
Guangxu Huang ◽  
Baolin Xing ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Coal Tar ◽  
Graphene Quantum Dots ◽  
High Yield ◽  
Coal Tar Pitch ◽  
Narrow Size Distribution ◽  
Material Source ◽  
Graphene Layers ◽  
Mild Conditions ◽  
Simple Strategy

Coal tar pitch (CTP), a by-product of coking industry, has a unique molecule structure comprising an aromatic nucleus and several side chains bonding on this graphene-like nucleus, which is very similar to the structure of graphene quantum dots (GQDs). Based on this perception, we develop a facile approach to convert CTP to GQDs only by oxidation with hydrogen peroxide under mild conditions. One to three graphene layers, monodisperse GQDs with a narrow size distribution of 1.7 ± 0.4 nm, are obtained at high yield (more than 80 wt. %) from CTP. The as-produced GQDs are highly soluble and strongly fluorescent in aqueous solution. This simple strategy provides a feasible route towards the commercial synthesis of GQDs for its cheap material source, green reagent, mild condition, and high yield.

scholarly journals Deep Ultraviolet to Near-Infrared Emission and Photoresponse in Layered N-Doped Graphene Quantum Dots

ACS Nano ◽  
2014 ◽  
Vol 8 (6) ◽  
pp. 6312-6320 ◽  
Author(s):  
Libin Tang ◽  
Rongbin Ji ◽  
Xueming Li ◽  
Gongxun Bai ◽  
Chao Ping Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Infrared ◽  
Graphene Quantum Dots ◽  
Infrared Emission ◽  
Doped Graphene ◽  
Deep Ultraviolet ◽  
Near Infrared Emission

scholarly journals Facile synthesis of preformed mixed nano-carbon structure from low rank coal

2018 ◽  
Vol 36 (1) ◽  
pp. 14-20 ◽  
Author(s):  
B. Manoj ◽  
Ashlin M. Raj ◽  
George Thomas Chirayil
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Bituminous Coal ◽  
Graphene Quantum Dots ◽  
Energy Resource ◽  
Low Rank ◽  
Tem Analysis ◽  
Graphene Layers ◽  
Simple Chemical ◽  
Nano Carbon

Abstract Coal is a natural energy resource which is mainly used for energy production via combustion. Coal has nanocrystals embedded in it, formed during the coalification process, and is an ideal precursor for nano-carbon dots and diamonds. Herein, we report a facile top-down method to synthesise nanodots and diamonds of the size of 5 nm to 10 nm from three different types of coal by simple chemical leaching. TEM analysis revealed the formation of a mixture of carbon dots, graphene layers, and quantum dots in bituminous coal and sub-bituminous coal. Raman analysis confirmed the existence of synthesized nanodiamond and nano-carbon mixed phase with defects associated with it. It is concluded that graphene quantum dots, nanodiamonds, graphene sheets and carbon dots present in coal can be extracted by simple chemical treatment. These structures can be tuned to photoluminescent material for various optoelectronic applications or energy harvesting devices like super capacitors.

scholarly journals A Novel Route to High-Quality Graphene Quantum Dots by Hydrogen-Assisted Pyrolysis of Silicon Carbide

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 277 ◽  
Author(s):  
Na Eun Lee ◽  
Sang Yoon Lee ◽  
Hyung San Lim ◽  
Sung Ho Yoo ◽  
Sung Oh Cho
Keyword(s):  
Quantum Dots ◽  
Silicon Carbide ◽  
Quantum Confinement ◽  
Graphene Quantum Dots ◽  
Simple Approach ◽  
Operating Conditions ◽  
High Quality ◽  
Graphene Layers ◽  
High Crystallinity ◽  
Effective Charge Transfer

Graphene quantum dots (GQDs) can be highly beneficial in various fields due to their unique properties, such as having an effective charge transfer and quantum confinement. However, defects on GQDs hinder these properties, and only a few studies have reported fabricating high-quality GQDs with high crystallinity and few impurities. In this study, we present a novel yet simple approach to synthesizing high-quality GQDs that involves annealing silicon carbide (SiC) under low vacuum while introducing hydrogen (H) etching gas; no harmful chemicals are required in the process. The fabricated GQDs are composed of a few graphene layers and possess high crystallinity, few defects and high purity, while being free from oxygen functional groups. The edges of the GQDs are hydrogen-terminated. High-quality GQDs form on the etched SiC when the etching rates of Si and C atoms are monitored. The size of the fabricated GQDs and the surface morphology of SiC can be altered by changing the operating conditions. Collectively, a novel route to high-quality GQDs will be highly applicable in fields involving sensors and detectors.

Deep Ultraviolet Photoluminescence of Water-Soluble Self-Passivated Graphene Quantum Dots

ACS Nano ◽  
2012 ◽  
Vol 6 (6) ◽  
pp. 5102-5110 ◽  
Author(s):  
Libin Tang ◽  
Rongbin Ji ◽  
Xiangke Cao ◽  
Jingyu Lin ◽  
Hongxing Jiang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Water Soluble ◽  
Deep Ultraviolet

Microwave-Assisted Synthesis of Nitrogen-Doped Multi-Layer Graphene Quantum Dots with Oxygen-Rich Functional Groups

2016 ◽  
Vol 69 (3) ◽  
pp. 357 ◽  
Author(s):  
Xiaobei Hou ◽  
Yibing Li ◽  
Chuan Zhao
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Atomic Ratio ◽  
Microwave Assisted Synthesis ◽  
Graphene Layers ◽  
Nitrogen Doped ◽  
Microwave Assisted ◽  
Layer Graphene ◽  
Potential Applications

Strong green-luminescent nitrogen-doped multi-layer graphene quantum dots (N-GQDs) have been prepared via a microwave-assisted hydrothermal method using glucose and urea as the starting materials. The fabricated N-GQDs show a highly crystalline structure and consist of ~3–10 graphene layers with an N/C atomic ratio 5.7 %. The wavelength-dependent luminescence emission behaviour is observed with a photoluminescence quantum yield of 5.2 %. The combination of the unique optical properties introduced by nitrogen doping with the high solubility in aqueous medium offered by the surface oxygen-rich functional groups in N-GQDs provides additional advantages for their potential applications in biolabelling and bioimaging.

Preparation of Graphene Quantum Dots and Their Biological Applications

2016 ◽  
Vol 31 (4) ◽  
pp. 337 ◽  
Author(s):  
SUN Xiao-Dan ◽  
LIU Zhong-Qun ◽  
YAN Hao
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Biological Applications

Effect of graphene quantum dots on intestinal imaging and mesenteric microcirculation in mice

2014 ◽  
Vol 35 (4) ◽  
pp. 372
Author(s):  
Yong-qiang MA ◽  
Zhen-guo WANG ◽  
Xue-li GOU ◽  
Na LI ◽  
Ya-qiang FENG ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Mesenteric Microcirculation
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