Selective Functionalization of Graphene at Defect‐Activated Sites by Arylazocarboxylic <i>tert</i>‐Butyl Esters

Halbig, Christian E.; Lasch, Roman; Krüll, Jasmin; Pirzer, Anna S.; Wang, Zhenping; Kirchhof, Jan N.; Bolotin, Kirill I.; Heinrich, Markus R.; Eigler, Siegfried

doi:10.1002/anie.201811192

Cited by 18 publications

(24 citation statements)

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“…Oxo‐G with a typical degree of functionalization of 60 % (oxo‐G 60 % ) displays a density of defects of about 2 % after annealing . Those defects can act as structural motifs and active sites for selective chemical functionalization . So far, the vast majority of studies on GO or oxo‐G based materials mainly focused on optimizing preparation and reduction methods, understanding preparation protocols, probing the reduction mechanism, and developing applications .…”

Section: Methodsmentioning

confidence: 99%

“…[9,14] Those defects can act as structural motifs and active sites for selective chemical functionalization. [17] So far, the vast majority of studies on GO or oxo-G based materials mainly focused on optimizing preparation and reduction methods, [18] understanding preparation protocols, probing the reduction mechanism, [19] and developing applications. [20] However, deep knowledge about the atomic structures and defects between oxidized and deoxygenated states in oxo-G are ambiguous.…”

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confidence: 99%

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Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

et al. 2020

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The thermal decomposition of graphene oxide (GO) is a complex process at the atomic level and not fully understood. Here, a subclass of GO, oxo-functionalized graphene (oxo-G), was used to study its thermal disproportionation. We present the impact of annealing on the electronic properties of a monolayer oxo-G flake and correlated the chemical composition and topography corrugation by twoprobe transport measurements, XPS, TEM, FTIR and STM. Surprisingly, we found that oxo-G, processed at 300 8C, displays CÀC sp 3-patches and possibly CÀOÀC bonds, next to graphene domains and holes. It is striking that those CÀOÀ C/C À C sp 3-separated sp 2-patches a few nanometers in diameter possess semiconducting properties with a band gap of about 0.4 eV. We propose that sp 3-patches confine conjugated sp 2-C atoms, which leads to the local semiconductor properties. Accordingly, graphene with sp 3-C in double layer areas is a potential class of semiconductors and a potential target for future chemical modifications.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

et al. 2020

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“…Das Kohlenstoffgitter in oxo‐G kann durch hochauflösende Transmissionselektronenmikroskopie (TEM) sichtbar gemacht werden . Chemisch verarbeitetes oxo‐G mit einem oxo‐Funktionalisierungsgrad von etwa 4 % (abgekürzt als oxo‐G 4 % ) enthält defektfreie Bereiche mit Durchmessern von durchschnittlich etwa 10 nm . Nach der Erhitzen auf 175 °C ist das oxo‐G 4 % disproportioniert und enthält Graphendomänen mit Durchmessern von ca.…”

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Identifizierung von halbleitenden Bereichen in thermisch behandeltem monolagigem Oxo‐funktionalisiertem Graphen

et al. 2020

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Die thermische Zersetzung von Graphenoxid (GO) ist auf atomarer Ebene ein komplexer Prozess und noch nicht vollständig verstanden. In dieser Untersuchung wurde eine Unterklasse von GO verwendet, oxofunktionalisiertes Graphen (oxo‐G), um die thermische Disproportionierung zu untersuchen. Wir stellen den Einfluss des Erhitzens auf die elektronischen Eigenschaften einer einschichtigen oxo‐G‐Flocke vor und korrelieren die chemische Zusammensetzung und die Topographie durch Zwei‐Kontakt‐Transportmessungen, XPS, TEM, FTIR und STM. Überraschenderweise fanden wir heraus, dass oxo‐G, das auf 300 °C erhitzt wurde, neben Graphendomänen und Löchern auch C‐C‐sp3‐Bereiche und möglicherweise C‐O‐C‐Bindungen enthält. Auffallend ist, dass diese C‐O‐C/C‐C‐sp3‐getrennten sp2‐Bereiche mit wenigen Nanometern Durchmesser Halbleitereigenschaften mit einer Bandlücke von etwa 0.4 eV aufweisen. Wir schlagen vor, dass sp3‐Bereiche konjugierte sp2‐C‐Atomgruppen einschließen, was zu den lokalen Halbleitereigenschaften führt. Dementsprechend ist Graphen mit sp3‐C in Doppelschichtbereichen eine potentielle Klasse von Halbleitern und ein potentielles Ziel für zukünftige chemische Modifikationen.

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“…Controlling the presence of minor species, such as metal impurities, carbon‐centered radicals or endoperoxide groups, is important to facilitate applications in biological systems . However, our finding moreover gives access to control the on‐plane regiochemistry of oxo‐G and graphene, respectively, bearing assumedly a high potential for advancing applications …”

Section: Figurementioning

confidence: 99%

“…[32] However,o ur finding moreover gives access to control the on-plane regiochemistry of oxo-G and graphene, respectively,b earing assumedly ah igh potential for advancing applications. [33]…”

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Brodie's or Hummers’ Method: Oxidation Conditions Determine the Structure of Graphene Oxide

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Gorelik

et al. 2019

Chemistry A European J

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Synthesis and studies of graphite oxide started more than 150 years ago and turned into a boom by the measurements of the outstanding physical properties of graphene. A series of preparation protocols emanated trying to optimize the synthesis of graphene oxide in order to obtain a less defective material, as source for graphene. However, over‐oxidation of the carbon framework hampered establishing structure‐property relationships. Here, the fact that two different synthetic methods for graphene oxide preparation lead to very similar types of graphene oxide with a preserved graphene lattice is demonstrated. Either sodium chlorate in nitric acid (similar to Brodie's method) or potassium permanganate in sulfuric acid (similar to Hummers’ method) treatment are possible; however, reaction conditions must be controlled. With a preserved carbon lattice analytical differences between the samples relate to the altered on‐plane functionality. Consequently, terming preparation protocols “according to Brodie's/Hummers’ method” is not sufficient.

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Selective Functionalization of Graphene at Defect‐Activated Sites by Arylazocarboxylic tert‐Butyl Esters

Abstract: Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Cited by 18 publications

References 53 publications

Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

Identification of Semiconductive Patches in Thermally Processed Monolayer Oxo‐Functionalized Graphene

Identifizierung von halbleitenden Bereichen in thermisch behandeltem monolagigem Oxo‐funktionalisiertem Graphen

Brodie's or Hummers’ Method: Oxidation Conditions Determine the Structure of Graphene Oxide

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