Hydrothermal Route for Cutting Graphene Sheets into Blue‐Luminescent Graphene Quantum Dots

Pan, Dengyu; Zhang, Jingchun; Li, Zhen; Wu, Minghong

doi:10.1002/adma.200902825

Cited by 2,540 publications

(2,255 citation statements)

References 31 publications

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“…As we know that the luminescence mechanism of the CDs was still not clearly understood, the proposed reason might be the rediative recombination [7]. The green luminescence of the CDs might be attributed to surface energy traps [7], and the blue emission of the C-dots might be attributed to zig-zag sites [31,32] due to the grapheme molecules embedded in the C-dots.…”

Section: Resultsmentioning

confidence: 99%

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source

Tan

Zhang

Tang

et al. 2013

Talanta

112

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Section: Resultsmentioning

confidence: 99%

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source

Tan

Zhang

Tang

et al. 2013

Talanta

112

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“…Their photoluminescence characteristics are linked to the sizes and ratio of sp 2 and sp 3 domains. The mechanism is considered complex and involves 1) defects' state emission/surface energy traps and 2) intrinsic state emissions, which include electron–hole recombination, quantum size effects/zigzag states 170, 171, 172, 173, 174. The emission characteristics were linked to surface chemistry and thus to alterations in the bandgap 175.…”

Section: Applications Of the Photochemical Activity Of Nanoporous Carmentioning

confidence: 99%

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

Bandosz

Ania

2018

Advanced Science

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Even though, owing to the complexity of nanoporous carbons' structure and chemistry, the origin of their photoactivity is not yet fully understood, the recent works addressed here clearly show the ability of these materials to absorb light and convert the photogenerated charge carriers into chemical reactions. In many aspects, nanoporous carbons are similar to graphene; their pores are built of distorted graphene layers and defects that arise from their amorphicity and reactivity. As in graphene, the photoactivity of nanoporous carbons is linked to their semiconducting, optical, and electronic properties, defined by the composition and structural defects in the distorted graphene layers that facilitate the exciton splitting and charge separation, minimizing surface recombination. The tight confinement in the nanopores is critical to avoid surface charge recombination and to obtain high photochemical quantum yields. The results obtained so far, although the field is still in its infancy, leave no doubts on the possibilities of applying photochemistry in the confined space of carbon pores in various strategic disciplines such as degradation of pollutants, solar water splitting, or CO2 mitigation. Perhaps the future of photovoltaics and smart‐self‐cleaning or photocorrosion coatings is in exploring the use of nanoporous carbons.

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“…18,19 Interestingly, GQDs are enriched with oxygen functional groups on their edges, whereby unique properties such as a non-zero bandgap and luminescence on excitation have been reported. [20][21][22] Furthermore, it is expected that GQDs can uniformly cover the target material due to their small size. Indeed, GQDs have been reported to serve as a composite member or coating material for energy storage devices.…”

Section: Introductionmentioning

confidence: 99%

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

et al. 2016

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Lithium-sulfur (Li-S) batteries are expected to overcome the limit of current energy storage devices by delivering high specific energy with low material cost. However, the potential of Li-S batteries has not yet been realized because of several technical barriers. Poor electrochemical performance is mainly attributed to the low electrical conductivity of the fully charged and discharged species, the irreversible loss of polysulfide anions and the decrease in the number of electrochemically active reaction sites during battery operation. Here, we report that the introduction of graphene quantum dots (GQDs) into the sulfur cathode dramatically enhanced sulfur/sulfide utilization, yielding high performance. In addition, the GQDs induced structural integrity of the sulfur-carbon electrode composite by oxygen-rich functional groups. This hierarchical architecture enabled fast charge transfer while minimizing the loss of lithium polysulfides, which is attributed to the physicochemical properties of GQDs. The mechanisms through which excellent cycling and rate performance are achieved were thoroughly studied by analyzing capacity versus voltage profiles. Furthermore, experimental observations and theoretical calculations further clarified the role played by GQDs by proving that C-S bonding occurs. Thus, the introduction of GQDs into Li-S batteries will provide an important breakthrough allowing their use as high-performance and low-cost batteries for next-generation energy storage systems. INTRODUCTIONRechargeable lithium-ion batteries are widely used in various applications, such as portable devices, bio-medical implants and electric vehicles, because of their high energy and power density. 1,2 However, current lithium-ion batteries based on the graphite and transition metal oxide couple have nearly reached their ceiling with respect to storage capability because of the limitations associated with their electrical properties and crystal structure. Therefore, breakthroughs in new energy storage systems that can surpass the current performance barrier of lithium-ion batteries should be brought about in a timely manner. Recently, Li-S batteries that can operate by the reversible electrochemical transformation between sulfur (S 8 ) and dilithium sulfide (Li 2 S) have attracted great attention because they can deliver high energy with a moderate voltage owing to the direct use of

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Hydrothermal Route for Cutting Graphene Sheets into Blue‐Luminescent Graphene Quantum Dots

Cited by 2,540 publications

References 31 publications

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

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