Organic molecules on atomically defined metal surfaces have been intensively investigated over the last two decades as a model system for gaining fundamental understanding of the molecular properties towards usage in applications such as electronic devices. However, the intrinsic electronic and structural properties of the organic molecules have been found to be strongly influenced by the interaction with the metallic support. Hence, for preserving and studying the intrinsic molecular properties, a weakly or non-interacting support (e.g., a thin film or bulk insulator) is essential. On the other hand, a weak interaction between the organic molecule and support often poses additional challenges to the characterization of the molecular systems caused by a generally lowered diffusion barrier in comparison to metals or by defects and charging often observed for insulators.
The goal of this thematic issue is to highlight recent experimental and theoretical developments in the atomic- and molecular-scale understanding of physically and electronically decoupled single molecules and molecular assemblies on surfaces. The key topics include fundamental aspects of the structural, electronic, and chemical properties as well as the characterization of decoupled molecular structures at the atomic-scale.
Potential contributions to this thematic issue may include - but are not limited to - the following topics: Molecular self-assemblies on ultrathin insulating/decoupling layers or bulk insulators, electronic structure and charging of decoupled molecules, chemical reactions as well as switching of molecules on decoupling/insulating layers.
Download all of the current publications in this thematic issue by clicking on "Download Issue".
Figure 1: Vertical slice of the frequency shift at the calcite–ethanol interface (a) and at the magnesite–eth...
Figure 2: Vertical slices showing the atomic positions of ethanol–carbon (black), hydroxy–oxygen (red) and hy...
Figure 3: Top view showing the position of all hydroxy–oxygen (red) and hydroxy–hydrogen (blue) atoms on (a) ...
Figure 1: a) STM topography of MoS2 on Ag(111) recorded at V = 1.2 V, I = 20 pA. Inset: Line profile of a mon...
Figure 2: Constant-height dI/dV spectra recorded (a) on a top and (b) on a hollow site of the moiré structure...
Figure 3: a) Stick-and-ball model of TCNQ. Gray, blue, and white spheres represent C, N, and H atoms, respect...
Figure 4: a) STM topography of a self-assembled TCNQ island on MoS2/Ag(111), recorded at V = 0.2 V, I = 20 pA...
Figure 5: a–d) Constant-height dI/dV maps of a TCNQ island on MoS2 recorded at the resonance energies derived...
Figure 6: a) STM topography image of a TCNQ island recorded at V = 1 V, I = 10 pA. b) Simulated (top panel) a...
Figure 1: (a) Skeletal formula of C42H28 including dimensions. (b) Sketch of the planar molecular configurati...
Figure 2: (a) STM image of C42H28 molecules on Pt(111) (bias voltage: 1 V, tunneling current: 100 pA, size: 1...
Figure 3: Spectra of dI/dV (dots) recorded above the different lobes of C42H28 on Pt(111) (feedback loop para...
Figure 4: (a) STM image of C42H28 molecules on Au(111) (−0.8 V, 50 pA, 30 × 30 nm2). Inset: STM image of a Au...
Figure 5: (a) Spectrum of dI/dV (dots) recorded above a C42H28 phenyl group on Au(111) with the spectroscopic...
Figure 6: (a) STM image of C42H28 molecules on graphene-covered Pt(111) (2 V, 100 pA, 34 × 34 nm2). Inset: Cl...
Figure 7: (a) Spectrum of dI/dV (dots) recorded above a C42H28 phenyl group on graphene-covered Pt(111) (feed...
Figure 1: Film-thickness dependent evolution of the DR spectra of (a) DBP on bare Ni(111) as well as of DBP o...
Figure 2: Imaginary part of the dielectric function obtained from the differential reflectance spectra of 1 M...
Figure 3: (a) LEED image (logarithmic intensity scale, contrast inverted) of the highly ordered DBP layer on ...
Figure 4: (a) Secondary electron cut-off (SECO) of DBP on bare Ni(111) (approx. 1.0 MLE), on h-BN/Ni(111) (le...
Figure 5: (a) N 1s, (b) C 1s, and (c) B 1s X-ray photoelectron spectra of DBP on bare Ni(111) (approx. 1.0 ML...
Figure 1: (a) Molecular structure of MnTUPCl. (b) Molecular structure of MnTUPOAc. (c) STM images of a monola...
Figure 2: (a) Bias voltage dependence of the measured current in the STM setup at the interface of HOPG and a...
Figure 3: UV–vis spectra of sample (solid traces) and reference solutions (dashed traces of (a) MnTUPCl and (...
Figure 1: Molecular structures of (a) 4-tetradecyloxybenzoic acid (BA-OC14) and (b) n-pentacontane (n-C50) us...
Figure 2: STM images of concentration dependent polymorphs of BA-OC14 formed at the 1-phenyloctane–HOPG inter...
Figure 3: (a) High-resolution STM image of the n-C50 monolayer formed at the 1-phenyloctane–HOPG interface. T...
Figure 4: Self-assembled monolayers of BA-OC14 formed on top of the n-C50 buffer layer at the 1-phenyloctane–...
Figure 5: (a) STM image showing the superposition of the n-C50 lamellae with those of BA-OC14 confirming the ...
Figure 6: On-command nucleation of BA-OC14 islands on top of the n-C50 buffer layer. (a) Schematic for the ST...
Figure 1: (a) C 1s and (b) F 1s core levels of F4PEN in monolayers on Ag(111) measured at DLS. (c) Reflectivi...
Figure 2: Valence band (a) and secondary electron region (b) of the UPS spectra of F4PEN on Ag(111). In (a), ...
Figure 3: (a) Valence band spectra for (fluorinated) pentacene in (sub)monolayer (solid lines) and multilayer...
Figure 1: Functionalized pyrene derivatives investigated in this work (DFT-optimized geometries in the gas ph...
Figure 2: Self-assembly of 1,3,6,8-tetrakis(pyridin-4-ylethynyl)pyrene (1, tetra) on hBN/Cu(111), as imaged b...
Figure 3: Self-assembly of 1,6-bis(pyridin-4-ylethynyl)pyrene (2, trans-like) on hBN/Cu(111). a) Overview ima...
Figure 4: Self-assembly of 1,8-bis(pyridin-4-ylethynyl)pyrene (3, cis-like) on hBN/Cu(111). a) Overview image...
Figure 5: dI/dV signatures of the pyrenes 1–3 on hBN/Cu(111) and template-induced gating. a), c), and e) STM ...
Figure 6: Diagrams summarizing the spectroscopic values determined for the pyrene derivatives 1–3. a) STS dat...
Figure 7: High-resolution STM images revealing the bias-dependent intramolecular contrast of the pyrene deriv...
Figure 8: Optical characterization. a) and b) UV–vis absorption (solid line) and emission spectra (dotted lin...
Figure 1: Molecular level schematic of integer charge transfer across dielectric films. Top: The ratio of int...
Figure 2: STM images of 6P deposited on (a,b) 2 ML MgO(100)/Ag(100) and (c,d) 3 ML MgO(100)/Ag(100). (a) Indi...
Figure 3: Photoemission momentum maps of 6P on MgO(100)/Ag(100) at energies of (a) 0.5 eV and (b) 2.5 eV belo...
Figure 4: He I ARUPS spectra for different preparations with the same saturation exposure of 6P (4 Å) on the ...
Figure 5: He I ARUPS spectra for a 6P dosing series on 2 ML MgO(100)/Ag(100) (ΦMgO = 2.58 eV) recorded at a t...
Figure 6: (a) Relation between integrated SOMO intensity and work function change induced by molecule adsorpt...
Figure 7: The work function after the deposition of a saturating dose of 5A (grey) and 6P (red) (Φmol) as a f...
Figure 8: Changes in the charge transfer and wetting behavior of 6P on MgO(100)/Ag(100) as a function of ΦMgO...
Figure 9: Thermal stability of 6P films (4 Å) on 2 ML of MgO with work functions (a) above and (b) below the ...
Figure 1: Chemical structure of (a) Co-DPP (1) and (b) 2H-TCNPP (2).
Figure 2: (a) STM image of the 1BL CoO film on Ir(100) with a corrugation of 100 pm and (b) side view of the ...
Figure 3: Low coverage of (a) 1 and (b) 2 deposited on 1BL CoO on Ir(100). 1 was deposited at 220 K substrate...
Figure 4: (a–d) Sequence of voltage-dependent STM images of a self-assembled island of 1 on 1BL of CoO. (a) a...
Figure 5: (a) 1 on 2BL CoO deposited at 200 K and imaged at 80 K. The molecules appear as round features unle...
Figure 6: (a) 2 on 2BL CoO deposited at 300 K and imaged at 80 K. The molecules assemble into compact ordered...
Figure 7: (a,b) Top and side view, respectively, of the relaxed structure of 1 on 1BL CoO according to our DF...
Figure 8: Calculated projected density of states (PDOS) near the Fermi energy of molecular orbitals with comp...
Figure 1: Structure search with BOSS (blue) and DFT (red). (I) The PES is sampled with BOSS by calculating en...
Figure 2: BOSS workflow and example performance. (a) Basic principle of the BOSS method, in which Bayesian op...
Figure 3: Degrees of freedom for the minimum energy search. (a) Three methyl group rotation angles θ, φ and ω...
Figure 4: Energy landscapes from preparatory BOSS simulations. (a) θ–ω 2D cross section of the 3D PES in the ...
Figure 5: Energetics of adsorption and mobility for surface adsorbates. (a) Adsorption energies (Eads) of the...
Figure 6: Relaxed stable adsorbate structures of camphor on Cu(111) in the 6D search, showing (a) chemisorpti...
Figure 7: Electronic properties of different camphor adsorbates. (a) The sum of partial charges (Δq) in the a...
Figure 1: STM images of PTCDA molecules on (a) Si(111)-(7 × 7), (b) partly CaF1-covered Si(111), and (c) CaF2...
Figure 2: STM images of individual PTCDA molecules on different surface areas. Imaging of PTCDA on a Si(111)-...
Figure 3: Statistical analysis of (a) the double-lobe orientation on the CaF1 layer and (b) the nearest-neigh...
Figure 4: Geometry-optimised adsorption geometry of a single PTCDA molecule on a CaF2(111) slap in (a) top vi...
Figure 1: (a) Schematic diagram of the radiative and non-radiative decay processes of an optical excitation o...
Figure 2: Overview spectra of 1.55 ML PTCDA on Cu(111) (red), of 0.50 ML PTCDA on hBN/Cu(111) (blue), and of ...
Figure 3: Zoom-in on the high-energy region (III) of the spectra. (a) 0.80 ML PTCDA/hBN/Cu(111) after deposit...
Figure 4: Fluorescence spectra of (a) 0.60 ML PTCDA and (b) 1.55 ML PTCDA on hBN/Cu(111) as deposited at 20 K...
Figure 5: (a) Fluorescence spectra of PTCDA on hBN/Cu(111) (left, blue spectra, prepared by deposition at 20 ...
Figure 6: Fluorescence spectra of 0.60 ML PTCDA/hBN/Cu(111) (blue, bottom) and 2.55 ML PTCDA/Cu(111) (red, to...
Figure 7: LEED pattern of (a) 1 ML PTCDA/Cu(111) and (b) 1.55 ML PTCDA/Cu(111) deposited at 300 K. On the lef...
Figure 8: LEED pattern of PTCDA layers on hBN/Cu(111). (a) LEED pattern of 2 ± 0.5 ML PTCDA/hBN/Cu(111). The ...
Figure 9: Raman modes of 0.90 ML PTCDA on hBN/Cu(111), measured with a dye laser with tunable wavelength (497...
Figure 10: FL spectra of 0.50 ML PTCDA on hBN/Cu(111), deposited at 20 K and subsequently annealed at 300 K (b...