Monolayer-to-thin-film transition in supramolecular assemblies: the role of topological protection

Laker, Zachary P. L.; Marsden, Alexander J.; Luca, Oreste De; Pia, Ada Della; Perdigão, Luı́s M. A.; Costantini, Giovanni; Wilson, Neil R.

doi:10.1039/c7nr03588h

Cited by 17 publications

(16 citation statements)

References 57 publications

(54 reference statements)

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“…We estimated the TMA molecular lattice constant to be d TMA = 1.654 nm from the distance between the second nearest neighbors in the hexamer. This value is in good agreement with the experimental − ,,,,− and DFT , results.…”

Section: Resultssupporting

confidence: 91%

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

et al. 2019

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Self-assembly of trimesic acid (TMA) molecules into the honeycomb structure with filled pores and the resulting host–guest chemistry are studied by the density functional theory (DFT) and Monte Carlo (MC) simulations. The DFT calculations demonstrate that a guest TMA molecule prefers a noncentral position in a relaxed hexagonal pore formed of six TMA molecules, and it is binded by two intermolecular interactions. The symmetric central position of the guest molecule is energetically favorable only in the honeycomb structure, which is compressed by more than 3%. Based on the estimated host–guest dimeric interactions, a model is proposed to identify the conditions for central and noncentral positioning of TMA molecules within the pore during their ordering into the honeycomb structure with partly filled pores. The MC simulations reveal that increase of the molecule–substrate interaction in the center of the pore or interactions of the central molecule with the cage molecules have a significant effect in preserving the central position of the guest molecule. However, if these interactions are not too strong, the noncentral position is favored due to multiplicity of noncentral arrangements in a hexagonal cage.

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Section: Resultssupporting

confidence: 91%

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

et al. 2019

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“…Room-temperature STM images of Nile Red deposited on Au(111) at a sub-ML coverage (∼0.5 ML) showed the formation of distinct molecular islands ranging from 10 to 40 nm in both as-deposited samples as well as those after thermal annealing at 120 °C (see Figure ). This is in line with studies using other organic compounds which found that a flat aromatic core promotes molecular adsorption and thus the formation of self-assembled molecular islands on surface terraces. − In as-deposited samples, two different molecular packings of Nile Red molecules coexist on the gold surface: according to the appearance of these molecular assemblies, one was called the four-leaf clover packing and the other was called dense-chain packing (see Figure ). An extended statistical analysis carried out on different areas of as-deposited samples revealed that, at sub-ML coverage, both packings formed on the surface with equal probability.…”

Section: Results and Discussionsupporting

confidence: 82%

Adsorption of Nile Red Self-Assembled Monolayers on Au(111)

et al. 2019

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The ability of Nile Red to self-assemble into supramolecular packings on Au(111) was studied using scanning tunneling microscopy and modeled through theoretical semiempirical calculations. At both submonolayer (sub-ML) and ML coverages, two distinct molecular packings, that is, four-leaf clover and dense chain, were observed, both weakly interacting with the underlying metal surface. Theoretical calculations suggested that the dipole moment plays a subtle role in both molecular assemblies, held together by hydrogen bonds between the Nile Red molecules. Furthermore, although both molecular assemblies were observed in as-deposited samples, a mild thermal annealing caused the transition from the four-leaf clover to the densechain packing, pointing out the greater stability of the dense-chain configuration. The study further emphasized how the established interactions between the Nile Red molecules are strongly influenced by the surrounding environment.

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“…It should however be noted that the main molecular axes of the TCNQ molecules align closely to the main crystallographic directions of the Bi 2 Se 3 (0001) surface. A similar situation has been reported for the 2D self‐assembly of other organic molecules on low‐interacting substrates such as graphite or graphene and is sometimes indicated as van der Waals epitaxy…”

Section: Resultssupporting

confidence: 72%

TCNQ Physisorption on the Topological Insulator Bi₂Se₃

et al. 2018

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Topological insulators are promising candidates for spintronic applications due to their topologically protected, spin-momentum locked and gapless surface states. The breaking of the time-reversal symmetry after the introduction of magnetic impurities, such as 3d transition metal atoms embedded in two-dimensional molecular networks, could lead to several phenomena interesting for device fabrication. The first step towards the fabrication of metal-organic coordination networks on the surface of a topological insulator is to investigate the adsorption of the pure molecular layer, which is the aim of this study. Here, the effect of the deposition of the electron acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules on the surface of a prototypical topological insulator, bismuth selenide (Bi Se ), is investigated. Scanning tunneling microscope images at low-temperature reveal the formation of a highly ordered two-dimensional molecular network. The essentially unperturbed electronic structure of the topological insulator observed by photoemission spectroscopy measurements demonstrates a negligible charge transfer between the molecular layer and the substrate. Density functional theory calculations confirm the picture of a weakly interacting adsorbed molecular layer. These results reveal significant potential of TCNQ for the realization of metal-organic coordination networks on the topological insulator surface.

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Monolayer-to-thin-film transition in supramolecular assemblies: the role of topological protection

Abstract: An innovative combination of TEM and STM sheds new insight into the growth of organic layers and reveals the importance of topology in controlling the transition from two- to three-dimensional structure.

Cited by 17 publications

References 57 publications

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

Adsorption of Nile Red Self-Assembled Monolayers on Au(111)

TCNQ Physisorption on the Topological Insulator Bi₂Se₃

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Monolayer-to-thin-film transition in supramolecular assemblies: the role of topological protection

Abstract: An innovative combination of TEM and STM sheds new insight into the growth of organic layers and reveals the importance of topology in controlling the transition from two- to three-dimensional structure.

Cited by 17 publications

References 57 publications

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

Trimesic Acid Molecule in a Hexagonal Pore: Central versus Noncentral Position

Adsorption of Nile Red Self-Assembled Monolayers on Au(111)

TCNQ Physisorption on the Topological Insulator Bi2Se3

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TCNQ Physisorption on the Topological Insulator Bi₂Se₃