Graphene quantum dots: an emerging material for energy-related applications and beyond

Zhang, Zhipan; Zhang, Jing; Chen, Nan; Qu, Liangti

doi:10.1039/c2ee22982j

Cited by 820 publications

(619 citation statements)

References 121 publications

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“…The sizes of GQDs in GQDs/MnO 2 -3 are ≈2-3 nm, and the lattice spacing of 0.34 nm is excellently indexed to the (002) spacing of graphitic carbon, which implies small sizes and high crystallinity, and this agrees with the previous report about GQDs. [23,24] The X-ray powder diffraction (XRD) is investigated to help understand the crystal structure of MnO 2 nanosheet arrays before and after in situ formed GQDs by PECVD. The results in Figure 3a show the crystal structures of MnO 2 nanosheet arrays, GQDs/MnO 2 -3, and GQDs/MnO 2 -10.…”

Section: Resultsmentioning

confidence: 99%

“…[23] Choi and co-workers regulated the bandgap of GQDs to form GQDs/ZnO heterostructures through the creation of ZnOC bonds, which revealed superior optical characteristics and unique blue emissions that have not been seen in pure ZnO. [24] Moreover, some studies have reported that GQDs can improve the poor conductivity of TMO, which is beneficial for further obtaining superior specific capacitance.…”

Section: Introductionmentioning

confidence: 99%

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Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

et al. 2018

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a great deal of research effort has been devoted on high energy density supercapacitors. According to the equation of energy density E = 1/2 CV 2 , the energy density (E) of supercapacitors can be enhanced by increasing either voltage window (V) or specific capacitance (C). [5] For high specific capacitance, one of the research efforts should concentrate on using transition metal oxides (TMO) (e.g., MnO 2 , RuO 2 ) as electrode materials. [6,7] They can provide great specific capacitance due to the pseudocapacitive characteristic. [8,9] Among TMO materials, MnO 2 is one of the most potential materials for supercapacitors due to its high theoretical specific capacitance, environmental friendliness, and the high practical voltage window (about 1 V). [2] However, it has suffered from intrinsically low conductivity and specific surface area, which severely restrict its further development in practical application of supercapacitors. In this regard, integrating nanostructured MnO 2 and conductive carbon materials to fabricate novel hybrid nanostructures is a plausible solution to overcome this obstacle. [4] Further, some research efforts have been accordingly performed to synthesize hybrid nanostructures electroactive materials for constructing supercapacitors with considerable performance. Some researchers accordingly synthesized highperformance nanostructured MnO 2 -carbon materials electrodes, whose specific capacitance is close to theoretical value. However, the undesirable contact resistances that produced by the weak and noncoherent TMO/conductor interfaces lead to sluggish kinetics for charge transport, which requires further improvement. [10,11] In order to further improve the energy density, some researchers have concentrated on enlarging the voltage window of supercapacitors. The applications of aqueous electrolytes have been limited by their theoretical voltage window (≈1.23 V) and the practical voltage window is mostly lower than about 1 V for supercapacitors. [12] To extend the voltage window, various techniques have been applied, such as dual shuttle-ion electrolytes, [13,14] pH adjustment of electrolytes, [15] and concentrated electrolytes. [16][17][18] All of these methods have complex processing technologies and sacrifice capacitance, so being difficult for practical applications. Recently, Zhu and co-workers

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

et al. 2018

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“…[7][8][9] Recent studies have shown that GQDs can serve as new type of ECL luminophores and may have promising applications in sensing due to their several obvious advantages such as facile preparation, low cost, easy labelling, and high ECL activity. [10] However, up to date, the GQDs-based ECL systems mainly use the strongly oxidizing reagent, S 2 O 8…”

Section: Introductionmentioning

confidence: 99%

An Electrochemiluminescent Biosensor Based on Interactions between a Graphene Quantum Dot−Sulfite Co‐reactant System and Hydrogen Peroxide

Chen

et al. 2017

ChemElectroChem

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Dedicated to Professor Qinjin Wan on the occasion of his 60th birthdayGraphene quantum dots (GQDs) are recently emerging carbon nanomaterials. GQDs have been recognized as attractive electrochemiluminescence (ECL) luminophores, owing to their environmental friendliness, facile preparation, easy labeling, and high ECL activity. However, in terms of the co-reactant of GQDs ECL, only strongly oxidative S 2 O 8 2À has been well studied and applied in GQD-based ECL sensing, which seriously limits the application of GQD ECL sensors. In the present work, we found that the commonly used reducing reagent, sulfite (SO 3 2À ), could serve as a new type of co-reactant of GQD ECL. Moreover, GQDs exhibited much higher ECL activity than spherical carbon quantum dots when using SO 3 2À as the co-reactant, owing to more abundant surface states of GQDs. Further investigation showed that GQD/SO 3 2À ECL could be sensitively quenched by H 2 O 2 at physiological pH. On this basis, new, green, and simple ECL chemical and biological sensors have been proposed for the detection of H 2 O 2 and biologically interesting molecules such as glucose. Additionally, the ECL reaction and sensing mechanisms have also been studied and discussed.

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“…Xing et al [15] reported that the formation of a nanometer-scale chemically responsive junction (CRJ) within a silver nanowire (AgNW) strongly affected to sensing properties of nanocomposites. Exposure of the CRJ-containing nanowire to ammonia (NH 3 ) induced a rapid (< 30 s) and reversible resistance change that was as large as ΔR/R 0 = (+) 138% in 7% NH 3 and observable down to 500 ppm NH 3 . Exposure to water vapor produced a resistance increase of ΔR/R 0 , H 2 O = (+) 10-15% (for 2.3% water) while nitrogen dioxide (NO 2 ) exposure induced a stronger concentrationnormalized resistance decrease of ΔR/R 0 , NO 2 = (−) 10-15% (for 500 ppm NO 2 ).…”

mentioning

confidence: 99%

“…This is because graphene possesses many excellent electrical properties, since it is an allotrope of carbon with a structure of a single two-dimensional (2D) layer of sp 2 hybridized carbon atoms. Graphene quantum dots (GQDs), as seen in [2,3], are a kind of 0D material made from small pieces of graphene. GQDs exhibit new phenomena due to quantum confinement and edge effects, which are similar to semiconducting QDs [4].…”

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confidence: 99%

Characterization of Humidity Sensing of Polymeric Graphene-Quantum-Dots composites incorporated with silver nanowires

Nang

Long²,

Thu³

et al. 2017

MaP

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Graphene quantum dots (GQDs) were synthesized and incorporated with polyethylenedioxythiophene:poly(4-styrenesulfonate) (PEDOT:PSS), Ag nanowires (AgNWs) to form a composite that can be used for enhancement of relative humidity (RH%) sensing. The composite films contained bulk heterojunctions of AgNW/GQD and AgNW/PEDOT:PSS. The sensors made from the composites responded well to relative humidity in a range from 10% to 50% at room temperature. With an AgNWs content ranging from 0.2 wt.% to 0.4 wt.% and 0.6 wt.%, the sensitivity of the relative humidity sensing devices based on AgNWs-doped GQDs+PEDOT:PSS composites was increased from 5.5% to 6.5 % and 15.2 %, respectively. The response time of the composite sensors was much improved due to AgNWs doping in the composites. For the 0.6 wt.% AgNWs-doped GQDs+PEDOT:PSS films, the best value of the recovery time was found to be of 30 s.

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Graphene quantum dots: an emerging material for energy-related applications and beyond

Cited by 820 publications

References 121 publications

Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

An Electrochemiluminescent Biosensor Based on Interactions between a Graphene Quantum Dot−Sulfite Co‐reactant System and Hydrogen Peroxide

Characterization of Humidity Sensing of Polymeric Graphene-Quantum-Dots composites incorporated with silver nanowires

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Graphene quantum dots: an emerging material for energy-related applications and beyond

Cited by 820 publications

References 121 publications

Heterostructural Graphene Quantum Dot/MnO2 Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

Heterostructural Graphene Quantum Dot/MnO2 Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

An Electrochemiluminescent Biosensor Based on Interactions between a Graphene Quantum Dot−Sulfite Co‐reactant System and Hydrogen Peroxide

Characterization of Humidity Sensing of Polymeric Graphene-Quantum-Dots composites incorporated with silver nanowires

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Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors

Heterostructural Graphene Quantum Dot/MnO₂ Nanosheets toward High‐Potential Window Electrodes for High‐Performance Supercapacitors