The origins of the broadband photoluminescence from carbon nitrides and applications to white light emitting

Gan, Zhixing; Shan, Yun; Chen, Jiarui; Gui, Qingfeng; Zhang, Qizhen; Nie, Shouping; Wu, Xiaohong

doi:10.1007/s12274-016-1073-2

Cited by 74 publications

(69 citation statements)

References 39 publications

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“…The emission wavelength spread from the violet color (for single tri‐s‐triazine) to the entire visible range. Our calculations for emission are underestimated in comparison to earlier reports on the blue, green, and white light emitting graphitic carbon nitride nanostructures . The CNQDs of larger dimensions mainly emit the red wavelength and stretch to the near infrared region.…”

Section: Resultscontrasting

confidence: 93%

“…In addition, it follows the energy gap profile due to the saturation of the finite size of the CNQDs. The predicted absorption gap for the largest CNQD (C45) is 2.81 eV which is in reasonable agreement with previous reports …”

Section: Resultssupporting

confidence: 92%

“…As a visible light driven photocatalyst, a carbon nitride nanocomposite already exhibits high activity in the photodegradation of nitrogen oxide, organic contaminants,, fuel conversion of CO 2 , and hydrogen evolution ,. Though CNs nanomaterials have received great attention due to high yield and broadband photoluminescence (PL), they have significantly advanced photocatalysis capabilities in comparison to its counterpart carbon‐based two‐dimensional graphene quantum dots (GQDs) . However, research into the theoretical electronic structure exploration of the origin of the superior photocatalytic properties as compared to GQDs still need an understanding of their ground state and excited state Frontier Orbitals (FOs) structure.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of Charge Separation and Frontier Orbital Structure in Graphitic Carbon Nitride and Graphene Quantum Dots

2018

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Graphene quantum dots (GQDs) and carbon nitride quantum dots (CNQDs), the latest addition to the carbon material family, are promising materials for numerous novel applications in optical sensing, photocatalysis, biosensing, and photovoltaics. However, understanding the photocatalytic capability of CNQDs compared to GQDs requires investigations of the charge behavior on the excited state energy surface. In this work, through time-dependent density functional tight binding (TD-DFTB) calculations, we show that CNQDs exhibit superior ground state frontier orbitals (FOs) localization. Strong localization of the FOs and excited state charge separation observed in the first excited state are caused by the relaxation of the structure. Excited energy surface investigations reveal spatial confinement of FOs to the stretched C-N bonds due to excited state structural relaxation. On the other hand, no such localized FOs structure was found for GQDs, presumably caused by its strong π-conjugated configuration not allowing large structural changes upon excitation. The optical absorption and emission of CNQDs is sensitive to size and does not show large variations with the shape of the QD. Our approach provides an explanation for the origin of the enhanced photocatalytic performance of CNQDs over GQDs and their characteristic FOs localization.

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Section: Resultscontrasting

confidence: 93%

Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Mechanism of Charge Separation and Frontier Orbital Structure in Graphitic Carbon Nitride and Graphene Quantum Dots

2018

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“…[55,56] From FAT-0 to FAT-2.0, PL peaks gradually decreases and the peak intensity trend reversely agrees with the HER on FAT polymers, indicating that a stepwise enhanced charge separation was obtained on the doped samples. While the larger portion of recombination signals are those ≈500-600 nm corresponding to the intra states including n-π* transition and defect-based states.…”

Section: The Origin Of Superior Performancementioning

confidence: 53%

Bandgap Engineering of Organic Semiconductors for Highly Efficient Photocatalytic Water Splitting

Wang

Silveri

Bayazit

et al. 2018

Advanced Energy Materials

146

101

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activity is highly dependent on the electronic structure of the photocatalyst, it is crucial to adjust the bandgap in order to utilize the highest possible proportion of visible photons and achieve the target of 10% solar to fuel conversion efficiency. [2] Moreover, bandgap tunable semiconductors are especially useful in the construction of a Z-scheme for water splitting, which is considered to be a more promising approach to solar H 2 production than the single photocatalyst-based water splitting system. [3][4][5][6][7][8] A Z-Scheme requires an appropriate match of redox potentials between two photocatalysts and two mediators. So far, the strate-

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“…[39] Das Einfügen von CN in verschiedene Bulk-Heterojunctions (BJH) verbesserte die Effizienz, [40,136] und CN/PBT zeigten PV-Eigenschaften, wobei CN als Elektronenakzeptor wirkte,w ährend PBT der Donor war.D ies wurde der Bildung eines BJH an der CN-PBT-Grenzfläche zugeschrieben. [37,38,[143][144][145] CN wirkten hierbei als Lochinjektionsschicht. [83,[138][139][140][141] Liao et al verwendeten CN in Perowskit-Solarzellen zur Verbesserung der Perowskitkristallinität, was zu einem hçheren Füllfaktor sowie einem hçheren Gesamtwirkungsgrad führte.…”

Section: Andere Bauelementeunclassified

Kohlenstoffnitridmaterialien für photochemische Zellen zur Wasserspaltung

et al. 2019

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Graphitische Kohlenstoffnitridmaterialien (CN) sind aufgrund ihrer einstellbaren Bandlücke, geeigneten Energiebandposition, hohen Stabilität unter harschen chemischen Bedingungen und geringen Kosten interessante Photokatalysatoren und heterogene Katalysatoren für zahlreiche Reaktionen. Allerdings befindet sich die Nutzung von CN in photoelektrochemischen (PEC) und photoelektronischen Bauelementen noch in einem frühen Stadium, da die Abscheidung einer hochwertigen und homogenen CN‐Schicht auf Substraten, die breite Bandlücke, die schlechte Ladungstrennungseffizienz sowie die geringe elektronische Leitfähigkeit noch Schwierigkeiten bereiten. In diesem Kurzaufsatz diskutieren wir Synthesewege zur Herstellung verschiedener Strukturen von CN auf Substraten und deren grundlegende photophysikalische Eigenschaften und photoelektrochemische Aktivität. Wir beschreiben die wesentlichsten Herausforderungen bei der Einbindung von CN in PEC‐Zellen sowie mögliche Wege zur Überwindung der bestehenden Beschränkungen zur Integration von CN‐Materialien in PEC und andere photoelektronische Bauelemente.

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The origins of the broadband photoluminescence from carbon nitrides and applications to white light emitting

Cited by 74 publications

References 39 publications

Mechanism of Charge Separation and Frontier Orbital Structure in Graphitic Carbon Nitride and Graphene Quantum Dots

Mechanism of Charge Separation and Frontier Orbital Structure in Graphitic Carbon Nitride and Graphene Quantum Dots

Bandgap Engineering of Organic Semiconductors for Highly Efficient Photocatalytic Water Splitting

Kohlenstoffnitridmaterialien für photochemische Zellen zur Wasserspaltung

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