Size dependent magnetic and optical properties in diamond shaped graphene quantum dots: A DFT study

2016 ◽  
Vol 99 ◽  
pp. 34-42 ◽  
Author(s):  
Ritwika Das ◽  
Namrata Dhar ◽  
Arka Bandyopadhyay ◽  
Debnarayan Jana
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Quantum Dots ◽  
Dft Study ◽  
Size Dependent

Revealing the role of nitrogen dopants in tuning the electronic and optical properties of graphene quantum dots via a TD-DFT study

2020 ◽  
Vol 22 (48) ◽  
pp. 28230-28237
Author(s):  
Min Yang ◽  
Zan Lian ◽  
Chaowei Si ◽  
Bo Li
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Nitrogen Doping ◽  
Graphene Quantum Dots ◽  
Dft Study ◽  
Electronic And Optical Properties ◽  
Td Dft

The tunable electronic and optical properties of graphene quantum dots achieved by nitrogen doping

A Nanoscale Adventure with Silicon: Synthesis, Surface Chemistry, and other Surprises

2015 ◽  
Vol 242 ◽  
pp. 383-390
Author(s):  
Md Hosnay Mobarok ◽  
Tapas K. Purkait ◽  
Jonathan G.C. Veinot
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Surface Chemistry ◽  
Research Group ◽  
Size Dependent ◽  
Earth Abundant ◽  
Potential Applications ◽  
Si Quantum Dots

The preparation and surface chemistry Si quantum dots (SiQDs) are currently an intense focus of research because of their size dependent optical properties and many potential applications. SiQDs offer several advantages over other quantum dots; Si is earth abundant, non-toxic and biocompatible. This account briefly highlights recent advancements made by our research group related to the synthesis, functionalization, surface dependent optical properties and applications of SiQDs.

scholarly journals Theory of optical properties of graphene quantum dots

2015 ◽  
Vol 10 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Isil Ozfidan ◽  
A. D. Güçlü ◽  
Marek Korkusinski ◽  
Pawel Hawrylak
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Quantum Dots

Tuning the electronic and optical properties of hexagonal boron-nitride nanosheet by inserting graphene quantum dots

2018 ◽  
Vol 32 (06) ◽  
pp. 1850084 ◽  
Author(s):  
Yi-Min Ding ◽  
Jun-Jie Shi ◽  
Min Zhang ◽  
Meng Wu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Graphene Quantum Dots ◽  
Band Gaps ◽  
Hybrid Structures ◽  
Electronic And Optical Properties ◽  
Boron Nitride Nanosheet ◽  
Optoelectronic Nanodevices

It is difficult to integrate two-dimensional (2D) graphene and hexagonal boron-nitride (h-BN) in optoelectronic nanodevices, due to the semi-metal and insulator characteristic of graphene and h-BN, respectively. Using the state-of-the-art first-principles calculations based on many-body perturbation theory, we investigate the electronic and optical properties of h-BN nanosheet embedded with graphene dots. We find that C atom impurities doped in h-BN nanosheet tend to phase-separate into graphene quantum dots (QD), and BNC hybrid structure, i.e. a graphene dot within a h-BN background, can be formed. The band gaps of BNC hybrid structures have an inverse relationship with the size of graphene dot. The calculated optical band gaps for BNC structures vary from 4.71 eV to 3.77 eV, which are much smaller than that of h-BN nanosheet. Furthermore, the valence band maximum is located in C atoms bonded to B atoms and conduction band minimum is located in C atoms bonded to N atoms, which means the electron and hole wave functions are closely distributed around the graphene dot. The bound excitons, localized around the graphene dot, determine the optical spectra of the BNC hybrid structures, in which the exciton binding energies decrease with increase in the size of graphene dots. Our results provide an important theoretical basis for the design and development of BNC-based optoelectronic nanodevices.

scholarly journals Graphene Quantum Dots as Flourishing Nanomaterials for Bio-Imaging, Therapy Development, and Micro-Supercapacitors

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 866
Author(s):  
Merve Kortel ◽  
Bhargav D. Mansuriya ◽  
Nicole Vargas Santana ◽  
Zeynep Altintas
Keyword(s):  
Quantum Dots ◽  
Structural Properties ◽  
Edge Effects ◽  
Quantum Confinement ◽  
Review Paper ◽  
Graphene Quantum Dots ◽  
Heteroatom Doping ◽  
Size Dependent ◽  
Bio Imaging ◽  
Therapy Development

Graphene quantum dots (GQDs) are considerably a new member of the carbon family and shine amongst other members, thanks to their superior electrochemical, optical, and structural properties as well as biocompatibility features that enable us to engage them in various bioengineering purposes. Especially, the quantum confinement and edge effects are giving GQDs their tremendous character, while their heteroatom doping attributes enable us to specifically and meritoriously tune their prospective characteristics for innumerable operations. Considering the substantial role offered by GQDs in the area of biomedicine and nanoscience, through this review paper, we primarily focus on their applications in bio-imaging, micro-supercapacitors, as well as in therapy development. The size-dependent aspects, functionalization, and particular utilization of the GQDs are discussed in detail with respect to their distinct nano-bio-technological applications.

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.

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