Synthesis of Molecular 2D Materials via Low-energy Electron Induced Chemical Reactions

Turchanin, Andrey

doi:10.2533/chimia.2019.473

Cited by 11 publications

(8 citation statements)

References 35 publications

(68 reference statements)

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“…Depending on the chemical and structural composition of the monolayer, the interaction of electron beams with SAMs can be used to initiate different processes that include partial desorption, − cross-linking of aromatic molecules, − and surface modification of their chemical functionality . As demonstrated in recent years, these fundamental processes in turn can be used for different types of lithography of organic − and inorganic , materials, the formation of chemical gradients on the surface, metal substrate work function modification, and transforming SAMs into carbon-based materials such as graphene , or carbon nanomembranes (CNMs). − …”

Section: Introductionmentioning

confidence: 99%

Odd–Even Effect in Electron Beam Irradiation of Hybrid Aromatic–Aliphatic Self-Assembled Monolayers of Fatty Acid

et al. 2021

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Electron irradiation of aromatic self-assembled monolayers (SAMs) in combination with different lithographic approaches provides an interesting alternative for high-resolution surface patterning. More recently, it has been also demonstrated that this process can be used for carbon nanomembrane (CNM) fabrication, which forms technologically attractive 2D materials, with potential applications in different areas of nanotechnology such as ultrafiltration and nanobiosensing. To better understand the relation between the original SAM structure and the resulting CNM formation, in the current study, we conduct systematic analysis of the electron irradiation process for a model SAM system deposited on Ag substrates and based on a homologue series of biphenyl substituted carboxylic acids [C 6 H 5 −C 6 H 4 −(CH 2 ) n −COO/Ag, n = 2−6] with different lengths of the aliphatic linker defined by the number n. Our results of X-ray photoelectron spectroscopy of irradiated monolayers show that the process of electron-induced desorption, cross-linking, and elimination of the SAM binding group depend on the parity of the parameter n (the odd−even effect). Our observations indicate a way for controlling thickness and purity of such nanomembranes, which are the key parameters determining the range of CNM applications.

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Section: Introductionmentioning

confidence: 99%

Odd–Even Effect in Electron Beam Irradiation of Hybrid Aromatic–Aliphatic Self-Assembled Monolayers of Fatty Acid

et al. 2021

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“…However, when these interactions occur in dense environments, reactive species resulting from such electroninduced dissociation can undergo further chemical reactions. This leads to the formation of new products [9][10][11] or can be exploited to fabricate novel materials with interesting properties [12,13]. Electron-induced chemical processes also receive attention with respect to research on the origin of organic molecules in space.…”

Section: Introductionmentioning

confidence: 99%

Molecular synthesis in ices triggered by dissociative electron attachment to carbon monoxide

et al. 2021

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Chemical reactions in mixed molecular ices as relevant in the context of astrochemistry can be initiated by electron-molecule interactions. Dissociative electron attachment (DEA) as initiating step is identified from the enhancement of product yields upon irradiation at particular electron energies. Herein, we show that DEA to CO leads to the formation of HCN in mixed CO/$$\hbox {NH}_{{3}}$$ NH 3 ice at electron energies around 11 eV and 16 eV. We propose that this reaction proceeds via insertion of the neutral C fragment into a N–H bond. In the case of CO/$$\hbox {H}_{{2}}$$ H 2 O and CO/$$\hbox {CH}_{{3}}$$ CH 3 OH ices, a resonant enhancement of the yields of HCOOH and $$\hbox {CH}_{{3}}$$ CH 3 OCHO, respectively, is observed around 10 eV. In both ices, both molecular constituents exhibit DEA processes in this energy range so that the energy-dependent product yield alone does not uniquely identify the relevant DEA channel. However, we demonstrate by comparing with earlier results on mixed ices where CO is replaced by $$\hbox {C}_{{2}}\hbox {H}_{{4}}$$ C 2 H 4 that DEA to CO is again responsible for the enhanced product formation. In this case, $$\hbox {O}^{\cdot -}$$ O · - activates $$\hbox {H}_{{2}}$$ H 2 O or $$\hbox {CH}_{{3}}$$ CH 3 OH which leads to the formation of larger products. We thus show that DEA to CO plays an important role in electron-induced syntheses in molecular ices. Graphical abstract

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“…Figure b shows the structure of the precursor molecules. Next, the SAM was cross-linked into CNM in a high vacuum chamber (<5 × 10 –8 mbar) using a low energy electron gun (Specs) with an electron energy of 100 eV and a dose of 50 mC/cm 2 . The described synthetic procedure results in a mechanically stable CNM of a monomolecular thickness of 1.2 nm (see Figure a(i) and Supporting Information, Figure S1 and pp 2–3 for details).…”

Section: Resultsmentioning

confidence: 99%

Plasmonic Metasurfaces Situated on Ultrathin Carbon Nanomembranes

et al. 2020

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During the past decade, optical metasurfaces consisting of designed nanoresonators arranged in a planar fashion were successfully demonstrated to allow for the realization of a large variety of flat optical components. However, in common implementations of metasurfaces and metasurface-based devices, their flat nature is thwarted by the presence of a substrate of macroscopic thickness, which is needed to mechanically support the individual nanoresonators. Here, we demonstrate that carbon nanomembranes (CNMs) having nanoscale thicknesses can be used as a basis for arranging an array of plasmonic nanoresonators into a metamembrane, allowing for the realization of genuinely flat optical devices. CNMs belong to the family of two-dimensional materials, and their thicknesses and mechanical, chemical, and electrical properties can be tailored by the choice of the molecular precursors used for their fabrication. We experimentally fabricate gold split-ring-resonator (SRR) metasurfaces on top of a free-standing CNM, which has a thickness of only about 1 nm and shows a negligible interaction with the incident light field. For optical characterization of the fabricated SRR CNM metasurfaces, we perform linear-optical transmittance spectroscopy, revealing the typical resonance structure of an SRR metasurface. Furthermore, numerical calculations assuming free-standing SRR arrays are in good overall agreement with corresponding experimental transmittance spectra. We believe that our scheme offers a versatile solution for the realization of ultrathin, ultra lightweight metadevices, and may initiate various future research directions and applications including complex sensor technologies, conformal coating of complex topographies with functional metasurfaces, fast prototyping of multilayer metasurfaces, and studying the optical properties of effectively free-standing nanoparticles without the need for levitation schemes.

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Synthesis of Molecular 2D Materials via Low-energy Electron Induced Chemical Reactions

Cited by 11 publications

References 35 publications

Odd–Even Effect in Electron Beam Irradiation of Hybrid Aromatic–Aliphatic Self-Assembled Monolayers of Fatty Acid

Odd–Even Effect in Electron Beam Irradiation of Hybrid Aromatic–Aliphatic Self-Assembled Monolayers of Fatty Acid

Molecular synthesis in ices triggered by dissociative electron attachment to carbon monoxide

Plasmonic Metasurfaces Situated on Ultrathin Carbon Nanomembranes

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