Surface functionalization with nonalternant aromatic compounds: a computational study of azulene and naphthalene on Si(001)

Abstract

Nonalternant aromatic π-electron systems show promises for surface functionalization due to their unusual electronic structure. Based on our previous experiences for metal surfaces, we investigate the adsorption structures, adsorption dynamics and bonding characteristics of azulene and its alternant aromatic isomer naphthalene on the Si(001) surface. Using a combination of density functional theory, ab initio molecular dynamics, reaction path sampling and bonding analysis with the energy decomposition analysis for extended systems, we show that azulene shows direct adsorption paths into several, strongly bonded chemisorbed final structures with up to four covalent carbon–silicon bonds which can be described in a donor–acceptor and a shared-electron bonding picture nearly equivalently. Naphthalene also shows these tetra-σ-type bonding structures in accordance with an earlier study. But the adsorption path is pseudo-direct here with a precursor intermediate bonded via one aromatic ring and strong indications for a narrow adsorption funnel. The four surface-adsorbate bonds formed lead for both adsorbates to a strong corrugation and a loss of aromaticity.

Adsorption of 4-(N,N-Dimethylamino)-4′-nitrostilbene on an Amorphous Silica Glass Surface

“…The 56 prepared initial structures (DANS plus glass) were subsequently optimized using plane-wave DFT with periodic boundary conditions, as implemented in VASP 6.2.1 − with the projector-augmented wave method . We employed the Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional and the D3 dispersion scheme with Becke–Johnson damping function. , The performance of D3-PBE in describing the adsorption of small molecules on silica has been benchmarked against (experimental) reference values by different authors − and this approach was also applied in several further computational studies. ,− To obtain an estimate for the possible energy uncertainty due to the functional choice, we applied the optimization process to four structures using the revised Perdew–Burke–Ernzerhof (RPBE) functional. The results of the comparison of PBE and RPBE are shown in Table S2, showing that the interaction energies agree to within 0.1 eV.…”

“… 45 , 46 The performance of D3-PBE in describing the adsorption of small molecules on silica has been benchmarked against (experimental) reference values by different authors 47 − 49 and this approach was also applied in several further computational studies. 23 , 50 − 53 To obtain an estimate for the possible energy uncertainty due to the functional choice, we applied the optimization process to four structures using the revised Perdew–Burke–Ernzerhof (RPBE) 54 functional. The results of the comparison of PBE and RPBE are shown in Table S2 , showing that the interaction energies agree to within 0.1 eV.…”

Atomic and molecular functionalisation of technological materials: an introduction to nanoscale processes on semiconductor surfaces

“…However, arranging the molecules on a surface so that their electronic properties could be coupled not only with the surface of underlying material but also within the monolayer and potentially with a multilayer that could be formed on top has been one of the biggest challenges in the field. The work of Kreuter and Tonner in this issue [2] is an in-depth investigation using computational methods to explore changes in the electronic properties and reactivity of azulene and naphthalene as they react with a perfect Si(001) surface.…”

Surface Characterization of Modified Electrodes Based on 4-(Azulen-1-yl)-2,6-bis((E)-2-(thiophen-2-yl)vinyl)pyridine

“…In order to improve the DLs for HM ions knowledge about the surface structure and morphology of CMEs are required [24]. They are useful for the comparison of CMEs which are prepared with similar monomers.…”