Tetracene Monolayer and Multilayer Thin Films on Ag(111):  Substrate-Adsorbate Charge-Transfer Bonding and Inter-Adsorbate Interaction

Gonella, Grazia; Dai, Hai‐Lung; Rockey, Thomas J.

doi:10.1021/jp709826q

Cited by 22 publications

(42 citation statements)

References 52 publications

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“…NP can be thought of as a nucleophile due to the presence of delocalized electrons that can be transferred to the substrate, as has been observed with many aromatic molecules on metal surfaces 23. Data from previous studies suggests that the amount of charge transfer from NP to the surface is ≈0.1 e per ring 24. This leaves clusters of two NP molecules with a net ≈1.2 e positive charge and the surface beneath them with a corresponding negative (image) charge.…”

Section: Resultsmentioning

confidence: 94%

Spontaneous Transmission of Chirality through Multiple Length Scales

Iski

Tierney

Jewell

et al. 2011

Chemistry A European J

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The hierarchical transfer of chirality in nature, from the nano-, to meso-, to macroscopic length scales, is very complex, and as of yet, not well understood. The advent of scanning probes has allowed chirality to be monitored at the single molecule or monolayer level and has opened up the possibility to track enantiospecific interactions and chiral self-assembly with molecular-scale detail. This paper describes the self-assembly of a simple, model molecule (naphtho[2,3-a]pyrene) that is achiral in the gas phase, but becomes chiral when adsorbed on a surface. This polyaromatic hydrocarbon forms a stable and reversibly ordered system on Cu(111) in which the transmission of chirality from single surface-bound molecules to complex 2D chiral architectures can be monitored as a function of molecular packing density and surface temperature. In addition to the point chirality of the surface-bound molecule, the unit cell of the molecular domains was also found to be chiral due to the incommensurate alignment of the molecular rows with respect to the underlying metal lattice. These molecular domains always aggregated in groups of three, all of the same chirality, but with different rotational orientations, forming homochiral "tri-lobe" ensembles. At a larger length scale, these tri-lobe ensembles associated with nearest-neighbor tri-lobe units of opposite chirality at lower packing densities before forming an extended array of homochiral tri-lobe ensembles at higher converges. This system displayed chirality at a variety of size scales from the molecular (≈1 nm) and domain (≈5 nm) to the tri-lobe ensemble (≈10 nm) and extended array (>25 nm) levels. The chirality of the tri-lobe ensembles dictated how the overall surface packing occurred and both homo- and heterochiral arrays could be reproducibly and reversibly formed and interchanged as a function of surface coverage. Finally, these chirally templated surfaces displayed remarkable enantiospecificity for naphtho[2,3-a]pyrene molecules adsorbed in the second layer. Given its simplicity, reversibility, and rich degree of order, this system represents an ideal test bed for the investigation of symmetry breaking and the hierarchical transmission of chirality through multiple length scales.

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Section: Resultsmentioning

confidence: 94%

Spontaneous Transmission of Chirality through Multiple Length Scales

Iski

Tierney

Jewell

et al. 2011

Chemistry A European J

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“…10 A possible reason for the intermolecular repulsion is the repulsion between parallel adsorption dipoles of identical molecules. These adsorption dipoles may originate either in charge transfer from the adsorbed molecules to the surface or vice versa 10 or in the displacement of electron density of the metal surface by an (inert) adsorbate ("push-back" effect). [39][40][41] Intermolecular repulsion can be also caused by Coulomb interaction between partially charged parts of molecules.…”

Section: Discussion Of the Phase Behavior For θ < 1 ML T < 180 Kmentioning

confidence: 99%

“…Common adsorption energies are therefore below 1 eV per molecule. 1,10,11 The weak and unspecific molecule-substrate interaction implies low diffusion and incorporation barriers and thus will affect the growth kinetics of organic semiconductor films on metals. The interaction between the molecules is also nonchemical, giving rise to considerable structural flexibility of the growing film.…”

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confidence: 99%

“…1 Yet the available experimental data on this interface is limited. 1,10,[33][34][35] The emphasis in the present study is placed on structural data collected with scanning tunneling microscopy (STM) and low energy electron diffraction (LEED); in particular we present a refined phase diagram of the Tc/Ag(111) interface in the coverage range 0 to 2.4 MLs. Based on the structural data presented here, electronic structure studies, 35 kinetic growth studies, etc., may be performed in the future.…”

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confidence: 99%

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Structure and growth of tetracene on Ag(111)

et al. 2011

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The structure of the tetracene/Ag(111) interface in the coverage range θ = 0 to 2.4 ML is studied with scanning tunneling microscopy (STM) at 8 K and with low energy electron diffraction (LEED) at T = 300 . . . 100 K. For θ 0.01 ML, one-dimensional (1D) diffusion of single molecules along 011 -directions is observed even at 8 K. For 0.1 ML < θ < 0.5 ML molecules are homogeneously distributed over the surface forming a disordered phase (static at T = 8 K, dynamic at T = 25 K), indicating a repulsive intermolecular interaction (δ-phase). For θ 0.5 ML, local ordering in the commensurate γ -phase is observed. Further increase of the coverage yields a compressed monolayer (ML) phase (θ ≡ 1 ML) with point-on-line registry (α-phase). The interaction between molecules has been calculated with the force-field approach to rationalize the molecular packing motifs in the various phases. Under most circumstances molecule-molecule interactions are repulsive, in agreement with experimental findings. A simulation of the adsorption up to θ = 1 ML according to the random sequential adsorption (RSA) algorithm shows that the disorder-to-order transition from the δ-to γ -phase occurs close to random close packing (RCP), θ = 0.5-0.6 ML. Since tetracene molecules are a two-dimensional (2D) representation of Onsager's hard rod model, this suggests that this phase transition is driven both energetically and entropically. For θ ≈ 2.23 ML a metastable bilayer phase with point-on-line coincidence is observed (β-phase). The basic structural unit of this phase is a triplet of molecules that are tilted along the long molecular axis against each other; at least one of these molecules is tilted out of the surface plane. Within the β-phase a superstructure of alternating rotation domains is observed. This superstructure has a period of 7.4 nm. The molecular packing in the β-phase resembles the packing in the bulk crystal structure of tetracene, its formation can therefore be interpreted as incipient pseudomorphic growth of tetracene on Ag(111). However, pseudomorphic growth cannot be continued beyond the β-phase.

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“…A number of the arrangement patterns (or ordered phases) of Tc molecules on the Ag(111) surface has been observed as a function of coverage 24,25 . The compressed monolayer (ML) αphase with point-on-line type of commensurability, which can undergo spontaneous structural transformation 25 , has been studied in detail by different experimental techniques 26,27 . Additionally, the fully commensurate γ-phase with submonolayer coverage has been discovered rather recently 24 .…”

Section: Introductionmentioning

confidence: 99%

Adsorption geometry and electronic properties of flat-lying monolayers of tetracene on the Ag(111) surface

et al. 2016

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The geometrical and electronic properties of the monolayer (ML) of tetracene (Tc) molecules on Ag(111) are systematically investigated by means of DFT calculations with the use of localized basis set. The bridge and hollow adsorption positions of the molecule in the commensurate γ-Tc/Ag(111) are revealed to be the most stable and equally favorable irrespective to the approximation chosen for the exchange-correlation functional. The binding energy is entirely determined by the long-range dispersive interaction. The former lowest unoccupied orbital remains being unoccupied in the case of γ-Tc/Ag(111) as well as in the α-phase with increased coverage. The unit cell of the α-phase with point-on-line registry was adapted for calculations based on the available experimental data and the computed structures of the γ-phase. The calculated position of the Tc/Ag(111) interface state is found to be noticeably dependent on the lattice constant of the substrate, however its energy shift with respect to the Shockley surface state of the unperturbed clean side of the slab is sensitive only to the adsorption distance and in good agreement with the experimentally measured energy shift.

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Tetracene Monolayer and Multilayer Thin Films on Ag(111): Substrate-Adsorbate Charge-Transfer Bonding and Inter-Adsorbate Interaction

Cited by 22 publications

References 52 publications

Spontaneous Transmission of Chirality through Multiple Length Scales

Spontaneous Transmission of Chirality through Multiple Length Scales

Structure and growth of tetracene on Ag(111)

Adsorption geometry and electronic properties of flat-lying monolayers of tetracene on the Ag(111) surface

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