Graphene Quantum Dot Solid Sheets: Strong blue-light-emitting &amp; photocurrent-producing band-gap-opened nanostructures

Bharathi, Ganapathi; Nataraj, D.; Premkumar, S.; Sowmiya, M.; Senthilkumar, K.; Thangadurai, T. Daniel; Khyzhun, O.Y.; Gupta, Mukul; Phase, D.M.; Patra, N.; Jha, S. N.; Bhattacharyya, D.

doi:10.1038/s41598-017-10534-4

Cited by 72 publications

(34 citation statements)

References 67 publications

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“…Since the emitted FL peaks of N-GQDs-NSs were weak, these harmonics emitted by the measuring instrument became observable and noticeable. The weak FL intensity emitted by samples is attributed to this fact that the obtained N-GQDs-NSs is mainly with sheet shapes (as explained in the HR-TEM results), displaying metallic characters 36 .…”

Section: Resultsmentioning

confidence: 71%

Natural Source-Based Graphene as Sensitising Agents for Air Quality Monitoring

Parvizi

Azad

Dashtian

et al. 2019

Sci Rep

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Natural carbon powder has been used as a precursor to prepare two main types of sensitising agents of nitrogen-doped carbon nanoparticles (N-CNPs) and nitrogen-doped graphene quantum dots coupled to nanosheets (N-GQDs-NSs) by using simple treatments of chemical oxidation and centrifugation separation. Characterization based on FTIR, XPS, XRD, Raman spectroscopy, FE-SEM, HR-TEM, AFM, UV-Vis and FL, revealed successful doping carbon nanoparticle with nitrogen with an average plane dimension of 50 nm and relatively smooth surface. The versatility of the prepared samples as sensitising agents was developed and established by exploiting its ability for detection of volatile organic compounds via simple optical fibre based sensing configuration. The comparative experimental studies on the proposed sensor performance indicate fast response achieved at a few tens of seconds and excellent repeatability in exposure to the methanol vapour. The low limit of detection of 4.3, 4.9 and 10.5 ppm was obtained in exposure to the methanol, ethanol and propanol vapours, respectively, in the atmosphere condition. This study gives insights into the chemical/physical mechanism of an enhanced economic optical fibre based gas sensor and illustrates it for diverse sensing applications, especially for chemical vapour remote detection and future air quality monitoring.

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Section: Resultsmentioning

confidence: 71%

Natural Source-Based Graphene as Sensitising Agents for Air Quality Monitoring

Parvizi

Azad

Dashtian

et al. 2019

Sci Rep

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“…Few reports claim that this blue emission is due size effect related . Recently we have also made an attempt to distinguish the intrinsic blue emission from GQDs by converting it into a graphene QD solid system . The green emission from GQDs is mostly attributed to defect states .…”

Section: Resultsmentioning

confidence: 99%

Interfacial Chemistry‐Modified QD‐Coupled CdTe Solid Nanowire and Its Hybrid with Graphene Quantum Dots for Enhanced Photocurrent Properties

et al. 2017

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Here in, we report the formation of CdTe quantum dot interconnected solid nanowire network by a bottom up process. The as formed nanostructure, also, named as quantum dot solid structure has exhibited a high magnitude photocurrent value of 0.25 mA, corresponding to the biasing voltage of 1.5 V. The improved photocurrent generation is a consequence of suppressed inter-dot charge transport resistance upon quantum solid nanowire network formation. This interesting network structure was further decorated with graphene quantum dots by optimizing the growth parameters. The hybrid nanostructure has shown a further enhancement in the photocurrent generation. Formation of such new nanostructures and their interesting photo-physical properties are discussed in detail.

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“…We anticipate that this understanding will importantly advance the research on GQD-based sensing devices. The choice of GQDs as a representative of the graphene-family materials is justified by the fact that GQD-related systems are multifunctional platforms, which can be used for production of micron-sized solid sheets (a promising working electrode material for electrochemical detection of heavy metals), 68 catalysts accelerating the reaction with HMs, 69 modified working electrodes, 70,71 aqueous solution electrolytes for optical and colorimetric detection of heavy metals [72][73][74][75][76][77][78][79][80][81][82] and adsorbent agents for removal of heavy metals. [83][84][85]…”

Section: Introductionmentioning

confidence: 99%

Interband transitions in closed-shell vacancy containing graphene quantum dots complexed with heavy metals

Shtepliuk

Yakimova

2018

Phys. Chem. Chem. Phys.

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High-performance optical detection of toxic heavy metals by using graphene quantum dots (GQDs) requires a strong interaction between the metals and GQDs, which can be reached through a functionalization/immobilization procedure or doping effect. However, commonly used surface activation approaches induce toxicity into the analysis system and, therefore, are ineligible from the environmental point of view. Here, we show that artificial creation of vacancy-type defects in GQDs can be a helpful means of intentional control of the active sites available for reaction with cadmium (Cd), mercury (Hg) and lead (Pb). Using restricted density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, we predict the effect of vacancy complexes not previously studied to describe the binding ability of GQDs towards metal adsorbates. We also show that the interband absorption in closed-shell GQDs complexed with Cd, Hg and Pb is strongly dependent on the vacancy type and can be efficiently tuned to attain the desired coloration of the analysis system. The results suggest that the vacancy defects play an important role in governing the hybridization between locally-excited (LE) and charge-transfer (CT) states of the GQDs. Based on the molecular orbital analysis and in-depth knowledge of excited states, the mechanisms underlying the interband absorption are discussed.

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Graphene Quantum Dot Solid Sheets: Strong blue-light-emitting & photocurrent-producing band-gap-opened nanostructures

Cited by 72 publications

References 67 publications

Natural Source-Based Graphene as Sensitising Agents for Air Quality Monitoring

Natural Source-Based Graphene as Sensitising Agents for Air Quality Monitoring

Interfacial Chemistry‐Modified QD‐Coupled CdTe Solid Nanowire and Its Hybrid with Graphene Quantum Dots for Enhanced Photocurrent Properties

Interband transitions in closed-shell vacancy containing graphene quantum dots complexed with heavy metals

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