Full DFT-D description of a nanoporous supramolecular network on a silicon surface

Abstract

We present a full density-functional-theory study taking into account the van der Waals interactions of a 2D supramolecular network adsorbed on the Si(111)√3x√3R30°-boron surface denoted SiB. We show that, contrarily to the previous calculations [B. Baris, V. Luzet, E. Duverger, Ph. Sonnet, F. Palmino, and F. Chérioux, Angew. Chem., Int. Ed. 50, 4094 (2011)] molecule-molecule interactions are attractive, thanks to van der Waals corrections which are essential to describe such systems. We confirm the importance of the substrate effect to achieve the molecular network on the boron doped silicon surface without covalent bond. Our simulated STM images, calculated in the framework of the bSKAN code, give better agreement with the experimental STM images than those obtained by the integrated LDOS calculations within the Tersoff-Hamann approximation. The tungsten tip presence is essential to retrieve three paired lobes as observed experimentally. The observed protrusions arise from the phenyl arms located above silicon adatoms.

Theoretical study of intermolecular interactions in nanoporous networks on boron doped silicon surface

“…A plane wave basis set with an energy cutoff of 400 eV is used. The Brillouin zone is sampled using a single gamma k-point, which is a reasonable choice due to the large size of the employed supercells (20.1Å × 20.1Å × 34Å), that has been already used in previous papers [14,24]. The ionic structures are relaxed until the various components of the force on each atom are less than 0.02 eV/Å.…”

“…In this theoretical study, we take into account the effects issued from non-local dispersion interactions (i.e., van der Waals) by using the semi-empirical correction proposed by Grimme [16][17][18]. In a first part, we present a structural and energetic study of the 1,3,5-tri(4-iodophenyl)benzene (TIB) and 1,3,5-triphenyl-benzene (THB) nanoporous networks, and we compare these results with those obtained for the 1,3,5-tri(4 -bromophenyl)benzene (TBB) network via similar DFT-D2 calculations [14]. In a second part, thanks to Laplacian study, we demonstrate that the interactions between TIB, TBB or THB molecules deposited on SiB substrate are not driven by covalent bonds.…”

“…In order to take the electronic structure of both molecule and substrate into account, density functional theory (DFT) calculations have been performed. The results have shown that the nanoporous network is governed by the subtle interplay between intermolecular and molecule-surface interactions with the van der Waals interactions playing a fundamental role [14]. In order to study the role of the end-groups that saturate the molecule termination, Makoudi et al [15] have synthesized two new molecules based on the same 1,3,5-triphenylbenzene molecular backbones.…”

“…Recently, very promising results have been obtained, showing the possibility of achieving a large-scale 2D open supramolecular network with the adsorption of the 1,3,5-tri(4 -bromophenyl)benzene (denoted TBB), on the Si(1 1 1) √ 3x √ 3R30 • -boron surface (denoted SiB) [14]. In order to take the electronic structure of both molecule and substrate into account, density functional theory (DFT) calculations have been performed.…”

Adsorption thermodynamics of cross-shaped molecules with one attractive arm on random heterogeneous square lattice

“…The problem is often complex, since the selfassembly process is affected by many factors such as temperature, surface morphology and surface coverage, chemical structure of the adsorbate molecule and interaction strength. Most of the theoretical studies in this field employ density functional theory (DFT) (Boukari et al 2013;Lüder et al 2014;Mura et al 2012;Mura et al 2010;Seydou et al 2014;Wang et al 2013), molecular dynamics (Blunt et al 2013;Eder et al 2011;Hermann and Rohr 2010;Martsinovich and Troisi 2010) and Monte Carlo simulations (Batina et al 1998;Fortuna et al 2010;Hermann and Rohr 2010;Silly et al 2008;Š im_ enas and Tornau 2014;Weber et al 2008).…”