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

Das, Rik; Dhar, Namrata; Bandyopadhyay, Amitava; Jana, Debnarayan

doi:10.1016/j.jpcs.2016.08.004

Cited by 45 publications

(31 citation statements)

References 46 publications

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“…It is clear from the above data that the G band for the most stable structure 'ab' remains almost unaltered. On the contrary, the Raman spectra of the least stable structure 'ae' exhibit several low intense modes with comparable intensities [16]. The mode (1674.04 cm −1 ) due to the solo contribution of the SW defect has been found to be blue shifted to 1830.66 cm −1 for the 'ae' system.…”

Section: Raman Spectramentioning

confidence: 91%

“…It is well established that electron confinement effect reduces with increasing size of graphene clusters and, for a system with 48 carbon (C) atoms, the bulk property predominates [16].…”

Section: Structural Modificationsmentioning

confidence: 99%

“…The underlying reasons for such difference are generally localization of electrons because of the quantum confinement effect and the existence of edge states. The GQDs are generally semiconducting in nature and the band gap can be tuned by varying the shape, size and surface chemistry [14][15][16]. Because of these tunable band gaps, GQDs can be used in photovoltaic devices [17,18].…”

Section: Introductionmentioning

confidence: 99%

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Effect and Characterization of Stone–Wales Defects on Graphene Quantum Dot: A First-Principles Study

Chakraborti¹,

Bandyopadhyay

Jana

2018

Condensed Matter

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A first principles based density functional theory (DFT) has been employed to identify the signature of Stone-Wales (SW) defects in semiconducting graphene quantum dot (GQD). Results show that the G mode in the Raman spectra of GQD has been red shifted to 1544.21 cm −1 in the presence of 2.08% SW defect concentration. In addition, the intensity ratio between a robust low intense contraction-elongation mode and G mode is found to be reduced for the defected structure. We have also observed a Raman mode at 1674.04 cm −1 due to the solo contribution of the defected bond. The increase in defect concentration, however, reduces the stability of the structures. As a consequence, the systems undergo structural buckling due to the presence of SW defect generated additional stresses. We have further explored that the 1615.45 cm −1 Raman mode and 1619.29 cm −1 infra-red mode are due to the collective stretching of two distinct SW defects separated at a distance 7.98 Å. Therefore, this is the smallest separation between the SW defects for their distinct existence. The pristine structure possesses maximum electrical conductivity and the same reduces to 0.37 times for 2.08% SW defect. On the other hand, the work function is reduced in the presence of defects except for the structure with SW defects separated at 7.98 Å. All these results will serve as an important reference to facilitate the potential applications of GQD based nano-devices with inherent topological SW defects.

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Section: Raman Spectramentioning

confidence: 91%

“…It is well established that electron confinement effect reduces with increasing size of graphene clusters and, for a system with 48 carbon (C) atoms, the bulk property predominates [16].…”

Section: Structural Modificationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect and Characterization of Stone–Wales Defects on Graphene Quantum Dot: A First-Principles Study

Chakraborti¹,

Bandyopadhyay

Jana

2018

Condensed Matter

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“…E-mail address: saievare@modares.ac.ir (E. Saievar-Iranizad). mentally benign, cost effective preparation and appropriate band positions against TiO 2 band positions (CV and VB bands) are a good candidate for improving disadvantages of TiO 2 and reducing the photoelectrons' loss [15][16][17][18][19][20][21] . GQDs show great promise in a wide range of applications such as photocatalysis [22,23] , sensing [24,25] , light emitting diodes (LEDs) [26] , and energy conversion or energy storage devices [27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

Graphene quantum dots decorated rutile TiO2 nanoflowers for water splitting application

Bayat

Saievar-Iranizad

2018

Journal of Energy Chemistry

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“…Therefore, many nanostructure‐based sensors have been presented for many chemicals by theoretical and experimental researchers . Graphene is one of the most important carbon nanostructures which has been applied frequently as a chemical sensor . In addition to infinite graphene, several researches have focused on the zero‐dimensional nanographenes which are finite fragments of graphene where their end atoms are saturated with hydrogen atoms .…”

Section: Introductionmentioning

confidence: 99%

The effect of electric field and Al doping on the sensitivity of hexa‐peri‐hexabenzocoronene nanographene to chloropicrin

Hosseinian

Gharachorloo

Lighvani

et al. 2018

Applied Organom Chemis

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It has been previously reported that the recently synthesized hexa‐peri‐hexabenzocoronene (HBC) nanographene cannot detect toxic chloropicrin (CP) gas. To overcome this problem, we examined the effect of Al doping and applying an electric field on the sensitivity of HBC towards CP gas by means of density functional theory calculations. We found that the Al‐doping process significantly increases the adsorption energy of CP gas from −7.1 to −39.9 kcal mol−1 but decreases the sensitivity of HBC. By applying an electric field, the HBC is polarized with two different electrostatic potentials on its different surfaces, which increases the adsorption energy. By increasing the electric field strength, the adsorption energy and electronic sensitivity of HBC are increased. We predicted that in the presence of an electric field of about −0.025 au, HBC can act as an electronic senor or a work function‐type sensor with a short recovery time. At this field, the electrical conductivity of HBC is significantly increased on CP adsorption which generates an electrical signal. Increasing the electric field to higher intensities is not favourable because of increasing recovery times, and decreasing it to lower intensities reduces the sensitivity of HBC.

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

Cited by 45 publications

References 46 publications

Effect and Characterization of Stone–Wales Defects on Graphene Quantum Dot: A First-Principles Study

Effect and Characterization of Stone–Wales Defects on Graphene Quantum Dot: A First-Principles Study

Graphene quantum dots decorated rutile TiO2 nanoflowers for water splitting application

The effect of electric field and Al doping on the sensitivity of hexa‐peri‐hexabenzocoronene nanographene to chloropicrin

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