Defect States Control Effective Band Gap and Photochemistry of Graphene Quantum Dots

2018 ◽  
Vol 10 (32) ◽  
pp. 27195-27204 ◽  
Author(s):  
Mauricio A. Melo ◽  
Frank E. Osterloh
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Graphene Quantum Dots ◽  
Defect States

THz band gap in encapsulated graphene quantum dots

2018 ◽  
Author(s):  
S. Massabeau ◽  
E. Riccardi ◽  
M. Rosticher ◽  
F. Valmorra ◽  
P. Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Graphene Quantum Dots

The Role of Reduced Graphene Oxide Concentration as Ablated Material on Optical Properties of Graphene Quantum Dots

2019 ◽  
Vol 948 ◽  
pp. 267-273 ◽  
Author(s):  
Fiqhri Heda Murdaka ◽  
Ahmad Kusumaatmaja ◽  
Isnaeni ◽  
Iman Santoso
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Oxide ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Optical Band Gap ◽  
Graphene Quantum Dots ◽  
Absorption Peak ◽  
Oxygen Defect ◽  
Reduced Graphene

We report the synthesize of Graphene Quantum Dots (GQDs) using ablation method with reduced Graphene Oxide (rGO) solution as a starting material. We have varied the concentration of rGO as following: 0.5, 2, 5 mg/ml and then have ablated them using 800 nm Ti-Sapphire femtosecond laser to obtain GQDs. From the UV-Vis data, we observed that the more concentration of rGO is being ablated, the more secondary absorption peak at 255.1 nm appeared. This secondary absorption peak is a characteristic of n-π* bonding due to the presence of oxygen defect which occurs as a result of the interaction between the laser and the water in rGO solution. We conclude that the population of oxigen defect in GQDs is increasing, following the increase of rGO concentration and could alter the optical properties of GQD. On the other hand, using Tauc’s plot, we confirm that the increase of rGO concentration as the ablated material does not alter GQDs optical band gap. However, it will slightly reduce both, direct and indirect Oxygen defect related optical band gap.

The effect of edges and shapes on band gap energy in graphene quantum dots

2016 ◽  
Vol 175 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Lanchakorn Kittiratanawasin ◽  
Supa Hannongbua
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Graphene Quantum Dots ◽  
Band Gap Energy ◽  
Gap Energy

Can inorganic salts tune electronic properties of graphene quantum dots?

2015 ◽  
Vol 17 (26) ◽  
pp. 17413-17420 ◽  
Author(s):  
Guilherme Colherinhas ◽  
Eudes Eterno Fileti ◽  
Vitaly V. Chaban
Keyword(s):  
Density Functional Theory ◽  
Quantum Dots ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Graphene Quantum Dots ◽  
Inorganic Salts ◽  
Ionic Clusters ◽  
Functional Theory ◽  
Free Ions

In this work, we apply density functional theory to study the effect of neutral ionic clusters adsorbed on the GQD surface. We conclude that both the HOMO and the LUMO of GQDs are very sensitive to the presence of ions and to their distance from the GQD surface. However, the alteration of the band gap itself is modest, as opposed to the case of free ions (recent reports). Our work fosters progress in modulating electronic properties of nanoscale carbonaceous materials.

Preparation and Optical Properties Research on Graphene Quantum Dots

2017 ◽  
Vol 727 ◽  
pp. 303-308 ◽  
Author(s):  
Yu Dong Shang ◽  
Xiu Hua Chen ◽  
Wen Hui Ma ◽  
Shao Yuan Li ◽  
Yue Chun Wang ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Quantum Dots ◽  
Optical Properties ◽  
Citric Acid ◽  
Band Gap ◽  
Potential Application ◽  
Graphene Quantum Dots ◽  
Optoelectronic Devices ◽  
High Crystallinity ◽  
Homo And Lumo

In this work, graphene quantum dots were simply and rapidly prepared by thermal decomposition of citric acid. The resulting graphene quantum dots shows good dispersion and high crystallinity, the sizes can be effectively adjusted by controlling the temperature of decomposition. The results indicate that with the increase of temperature, the size of GQDs increased from 2 nm to 12 nm. The effect of the size of graphene quantum dots on the optical properties were carefully studied. Based on the optical properties and electrochemical results, the HOMO and LUMO value of GQDs with different sizes were obtained and the band gap becomes smaller from 3.36 eV to 2.87 eV with the increase of size of GQDs, which provides a potential application in the field of optoelectronic devices.

Synthesis and luminescence of ceria decorated graphene quantum dots (GQDs): Evolution of band gap

2017 ◽  
Vol 184 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Poonam R. Kharangarh ◽  
Siva Umapathy ◽  
Gurmeet Singh
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Graphene Quantum Dots

Independent Tuning of the Band Gap and Redox Potential of Graphene Quantum Dots

2011 ◽  
Vol 2 (10) ◽  
pp. 1119-1124 ◽  
Author(s):  
Xin Yan ◽  
Binsong Li ◽  
Xiao Cui ◽  
Qingshuo Wei ◽  
Keisuke Tajima ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Redox Potential ◽  
Band Gap ◽  
Graphene Quantum Dots

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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