Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35

• conversion of polymer chains to 8-carbon armchair graphene nanoribbons was observed to be efficient at the Au(111) monatomic step at around 670–720 K. The asymmetric distribution of periodic vacancies can form frontier orbitals with wiggly and linear geometries. On-surface synthetic nanoarchitectonics may

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• . The significantly reduced resonance width allowed for resolving vibronic states in both frontier orbitals on graphene/Pt(111) by STS. The semiconducting 2D material MoS2 may act as a decoupling layer for molecules from the underlying metal substrate if the molecular resonances lie within the MoS2

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• ]. This again points to a difference in the bonding character on the two surfaces. Several studies have probed the influence of the adsorption on metal-supported hBN layers on the electronic structure of large organic molecules, namely their frontier orbitals, by PES [36] or STS [37][38]. However, to the

Controlling the electronic and physical coupling on dielectric thin films

• Philipp Hurdax,
• Michael Hollerer,
• Larissa Egger,
• Georg Koller,
• Xiaosheng Yang,
• Anja Haags,
• Serguei Soubatch,
• Frank Stefan Tautz,
• Mathias Richter,
• Alexander Gottwald,
• Peter Puschnig,
• Martin Sterrer and
• Michael G. Ramsey

Beilstein J. Nanotechnol. 2020, 11, 1492–1503, doi:10.3762/bjnano.11.132

• layer is not a sufficient condition for decoupling. Although it reduces wave function overlap with the substrate, it can in fact promote charge transfer via tunneling. The determining factor is the energy level alignment of the frontier orbitals of the adsorbate relative to the Fermi level (EF) of the

• until now because many of the standard techniques cannot easily distinguish between charged and neutral species. For reasonably large molecules with delocalized frontier orbitals, the integer charge is spread over many atoms and the resulting chemical shift will be too small to be seen with X-ray

Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)

• Domenik M. Zimmermann,
• Knud Seufert,
• Luka Ðorđević,
• Tobias Hoh,
• Sushobhan Joshi,
• Tomas Marangoni,
• Davide Bonifazi and
• Willi Auwärter

Beilstein J. Nanotechnol. 2020, 11, 1470–1483, doi:10.3762/bjnano.11.130

• at the submolecular level via STM and STS, e.g., reveal to be close to the gas-phase-like frontier orbitals. The electronic landscape of the hBN/Cu(111) template induces a periodic modulation of the electronic structure of the pyrene films at the single digit nanometer scale. The on-surface STM/STS

• (positive sample bias) spectral regions. Tentatively, the characteristic signatures were assigned to the HOMO, LUMO, and LUMO+1. The colored bars in Figure 5 highlight the energy positions of these frontier orbitals (determined as the bias voltage at the half maximum of the MO leading edge). The observation

•  3b, and Figure 4b) [17], distinct intramolecular features of electronic origin emerged (see also Figure S12, Supporting Information File 1). A comparison to the Kohn–Sham orbitals (see Figure 1) and to the frontier orbitals calculated in the EHT scheme (see insets in Figure 7) revealed striking

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• the design of new molecular electronic devices since they affect the charge carrier injection and therefore the device efficiency. An important process to consider is the electronic interaction of organic molecules that are in direct contact with the metal, i.e., the interaction of frontier orbitals

• indicative of a strong electronic interaction of first-layer molecules with the Ni(111) substrate. A similar broadening was observed for DBP on Ag(111), where a mixing of the molecular frontier orbitals with the metal bands of the substrate was concluded [26]. After about 0.25 monolayer equivalents (MLE

• to decouple the DBP molecules from the Ni(111) substrate. This statement is supported by the vacuum level alignment of the frontier orbitals, which was concluded from our UPS data. The investigation of the chemical structure by means of XPS revealed that the DBP adsorption also mildly influences the

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• superstructure characterize the adsorption phase. The highest occupied molecular orbital of C42H28 on Au(111) exhibits weak vibronic progression while unoccupied molecular resonances appear with a broad line shape. In contrast, vibronic subbands are present for both frontier orbitals of C42H28 on graphene. They

• indication of a vibronic fine structure. The molecular superstructure on graphene is similar to the assembly on Au(111), albeit with a lower molecule surface density, and dI/dV data exhibit vibronic progression in both frontier orbitals, which reflects the effective separation of C42H28 from the metal

• similar tip–molecule distances in the experiment. Vibronic fine structure is visible in the two frontier orbitals giving rise to vibronic subbands of the HOMO, H1 and H2, with equidistant spacings of 180 ± 10 mV, and for the LUMO, L1 and L2, with equidistant spacings of 220 ± 10 mV. In order to clearly

Pure and mixed ordered monolayers of tetracyano-2,6-naphthoquinodimethane and hexathiapentacene on the Ag(100) surface

• Robert Harbers,
• Timo Heepenstrick,
• Dmitrii F. Perepichka and
• Moritz Sokolowski

Beilstein J. Nanotechnol. 2019, 10, 1188–1199, doi:10.3762/bjnano.10.118

• the frontier orbitals of the respective molecules we refer to Supporting Information File 1.) Accordingly, in the gas phase one does not expect spontaneous electron transfer from HTPEN to TNAP. This in contrast to the previously studied situation for the TTT/TNAP mixed structure on the Au(111) surface

• . The error of the integer matrix elements is smaller than 0.03. Supporting Information Supporting Information File 170: Frontier orbitals of molecules under study. Acknowledgements We thank Sacha Thinius and Thomas Bredow for discussions on the stability of the HTPEN monolayer and Christine Brülke

The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface

• Luiza Buimaga-Iarinca and
• Cristian Morari

Beilstein J. Nanotechnol. 2019, 10, 706–717, doi:10.3762/bjnano.10.70

• of the transition metal in each structure. For each system we performed a qualitative analysis of the contributions to the frontier orbitals in the adsorbed molecule by integrating the PDOS of all atoms in a range of 0.1 eV around the corresponding energies. The results are presented in Supporting

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• of the variation between the respective KCl/metal systems indicates the degree of interaction of the frontier orbitals with the underlying metal. The results confirm that the so-called IDIS model developed by Willenbockel et al. applies not only to molecular layers on bare metal surfaces, but also to

• demonstrated by the observation of the unperturbed gas-phase-like frontier orbitals of pentacene on this substrate [3]. A weak interaction is nevertheless suggested by the observed shift of the orbital energies of the admolecule [4][7][8]. In scanning tunneling spectroscopy (STS) experiments on pentacene, two

• statistical evaluations of the measured molecules. Spatial imaging at the energies of the orbitals observed in STS yields the spatial distribution of the frontier orbitals of pentacene [2][3][4]. For +1.2 V, two prominent lobes connected by a series of dimmer lobes are observed (Figure 3a). This structure can

Preparation of alginate–chitosan–cyclodextrin micro- and nanoparticles loaded with anti-tuberculosis compounds

• Albert Ivancic,
• Fliur Macaev,
• Fatma Aksakal,
• Veaceslav Boldescu,
• Serghei Pogrebnoi and
• Gheorghe Duca

Beilstein J. Nanotechnol. 2016, 7, 1208–1218, doi:10.3762/bjnano.7.112

• interactions with isoconazole. Multiple hydrophobic contacts of amino acids with the inhibitor were indicated by green spheres in Figure 12b. Frontier molecular orbital analyses The analysis of specificity of the enzyme–ligand interaction is closely related to the analysis of frontier orbitals (HOMO and LUMO

• ) in molecular systems. The electron density distribution in the frontier orbitals of the enzyme–ligand complexes under study provides information about the donor–acceptor character of the interactions inside the complexes. The electronic structure calculations were carried out with Gaussian 09 using

• DFT at the B3LYP/6-31G (d,p) level of theory. The 3D structure of isoconazole and the InhA binding site was taken from the docking calculations. The electron density distribution on the frontier orbitals formed by the active-site residues of InhA with isoconazole is shown in Figure 13. As seen in

Effects of spin–orbit coupling and many-body correlations in STM transport through copper phthalocyanine

• Benjamin Siegert,
• Andrea Donarini and
• Milena Grifoni

Beilstein J. Nanotechnol. 2015, 6, 2452–2462, doi:10.3762/bjnano.6.254

• their signatures in transport are investigated. We first derive a minimal model Hamiltonian in a basis of frontier orbitals that is able to reproduce experimentally observed singlet–triplet splittings. In a second step SOI effects are included perturbatively. Major consequences of the SOI are the

• singly occupied molecular orbital (SOMO). When the molecule is in its anionic groundstate, this orbital does not become doubly occupied [7]. Hence, the orbitals most relevant for transport (frontier orbitals) are the SOMO (S), the HOMO (H) and the two degenerate LUMOs (Lzx/yz), which transform according

• four frontier orbitals can then be characterized by the phases φi acquired under rotations of π/2 around the main molecular symmetry axis. For the SOMO φS = π, for the HOMO φH = 0 and for the two LUMOs φL± = ±π/2. Many-body Hamiltonian in the frontier orbitals basis In order to set up a minimal many

Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

• Riccardo Frisenda,
• Simge Tarkuç,
• Elena Galán,
• Mickael L. Perrin,
• Rienk Eelkema,
• Ferdinand C. Grozema and
• Herre S. J. van der Zant

Beilstein J. Nanotechnol. 2015, 6, 1558–1567, doi:10.3762/bjnano.6.159

• molecule and metal [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Especially important are the alignment of the frontier orbitals to the metal Fermi level and the hybridization of these orbitals with states in the metallic electrodes [22][23][24][25]. A mechanically stable contact and strong

Electron and heat transport in porphyrin-based single-molecule transistors with electro-burnt graphene electrodes

• Hatef Sadeghi,
• Sara Sangtarash and
• Colin J. Lambert

Beilstein J. Nanotechnol. 2015, 6, 1413–1420, doi:10.3762/bjnano.6.146

• graphene electrodes by planar aromatic anchor groups. Due to the efficient π–π overlap between the anchor groups and graphene and the location of frontier orbitals relative to the graphene Fermi energy, we predicted HOMO-dominated transport and a positive thermopower as high as 280 μV/K. By gating the

• graphene electrodes (EBG) using the nonequilibrium Green’s function method and density functional theory. The porphyrin-based molecule is bound to the EBG electrodes by planar aromatic anchor groups. Due to the efficient π–π overlap between the anchor groups and graphene and the location of frontier

• orbitals relative to the EBG Fermi energy, we predict HOMO-dominated transport. An on–off ratio as high as 150 is predicted for the device, which could be utilized with small gate voltages in the range of ±0.1 V. A positive thermopower of +280 μV/K is predicted for the device at the theoretical Fermi

Charge carrier mobility and electronic properties of Al(Op)₃: impact of excimer formation

• Andrea Magri,
• Pascal Friederich,
• Bernhard Schäfer,
• Valeria Fattori,
• Xiangnan Sun,
• Timo Strunk,
• Velimir Meded,
• Luis E. Hueso,
• Wolfgang Wenzel and
• Mario Ruben

Beilstein J. Nanotechnol. 2015, 6, 1107–1115, doi:10.3762/bjnano.6.112

• . The electrostatic interaction with the environment leads to the localization of the frontier orbitals. Energy levels of Al(Op)3 calculated with different conditions, namely, HOMO and LUMO in vacuum (vac.) and in a self-consistent electrostatic environment (env.), with electron affinity (EA) and

Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes – a new strategy for OLED materials

• Pascal R. Ewen,
• Jan Sanning,
• Tobias Koch,
• Nikos L. Doltsinis,
• Cristian A. Strassert and
• Daniel Wegner

Beilstein J. Nanotechnol. 2014, 5, 2248–2258, doi:10.3762/bjnano.5.234

• transfer; density-functional theory; frontier orbitals; hybridization; OLED; Pt(II) complex; scanning tunneling microscopy; scanning tunneling spectroscopy; triplet emitters; Introduction Organic light emitting diodes (OLEDs) based on phosphorescent Ir(III) or Pt(II) complexes (also referred to as triplet

• the relevant frontier orbitals [11][12][13][14][15]. Several studies have performed STM and STS on organometallic compounds, mainly on porphyrins and phthalocyanines [16][17][18][19][20][21][22]. Considering this general success, it is surprising that phosphorescent complexes have barely been

• (phosphorescent) triplet emitters both in monomeric and aggregated form [31][32]. We identified a number of occupied and unoccupied frontier orbitals. Comparison with density functional theory (DFT) calculations allows the unambiguous assignment of all MOs from the HOMO–2 to the LUMO+2. We found that the

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• frontier orbitals (c) HOMO and (d) LUMO. Blue, red and grey spheres represent cobalt, oxygen and carbon atoms respectively. Schematic representation of the starting configurations with possible Co2(CO)8 orientations, considered in this study, on FOH-SiO2 surfaces. In POH-SiO2 surfaces some of the OH groups

STM study on the self-assembly of oligothiophene-based organic semiconductors

• Elena Mena-Osteritz,
• Marta Urdanpilleta,
• Erwaa El-Hosseiny,
• Berndt Koslowski,
• Paul Ziemann and
• Peter Bäuerle

Beilstein J. Nanotechnol. 2011, 2, 802–808, doi:10.3762/bjnano.2.88

• under negative bias [19][20]. Our theoretical calculations support the experimental findings (Figure 2, right), showing no contribution of the end-function to the occupied frontier orbitals (HOMO and HOMO−1) close to the Fermi level. This arrangement stabilizes the monolayer by neutralizing the dipole

Septipyridines as conformationally controlled substitutes for inaccessible bis(terpyridine)-derived oligopyridines in two-dimensional self-assembly

• Daniel Caterbow,
• Daniela Künzel,
• Michael G. Mavros,
• Axel Groß,
• Katharina Landfester and
• Ulrich Ziener

Beilstein J. Nanotechnol. 2011, 2, 405–415, doi:10.3762/bjnano.2.46

• no charge accumulation. While the molecules are very similar, a closer look at the frontier orbitals reveals key differences. In both isomers, the HOMO and LUMO are mainly localized on the backbone pyridine and the pyridines directly connected to it. In the 3,3'-PhSpPy (15) molecule, the HOMO extends

• the simulated STM images, a simple Tersoff–Hamann [37] approach was used. Orbitals in a given energy range close to the frontier orbitals were added and the resulting density was plotted. The orbitals were generated with Gaussian 03 from geometries that were obtained from relaxation of planar systems