Impact of fluorination on interface energetics and growth of pentacene on Ag(111)

• Qi Wang,
• Meng-Ting Chen,
• Antoni Franco-Cañellas,
• Bin Shen,
• Thomas Geiger,
• Holger F. Bettinger,
• Frank Schreiber,
• Ingo Salzmann,
• Alexander Gerlach and
• Steffen Duhm

Beilstein J. Nanotechnol. 2020, 11, 1361–1370, doi:10.3762/bjnano.11.120

• . The F4PEN monolayer was essentially lying on Ag(111), and multilayers adopted π-stacking. Our study shed light not only on the F4PEN–Ag(111) interface but also on the fundamental adsorption behavior of fluorinated pentacene derivatives on metals in the context of interface energetics and growth mode

• intermediate case. We determined the vertical adsorption heights of F4PEN (sub)monolayers on Ag(111) employing the XSW technique [64][65][66][67]. The lateral order in the monolayer was determined by LEED. Possible chemical interactions between F4PEN and the substrate were studied by XPS. The energy level

• integer. The coherent fraction 0 ≤ fH ≤ 1 describes the degree of vertical order of the adsorbate atoms, with fH = 0 for a completely disordered system and fH = 1 for all probed adsorbate atoms having the same adsorption distance. XSW measurements were performed for two (sub)monolayer coverages of F4PEN

Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS₂ field-effect transistors

• Jakub Jadwiszczak,
• Pierce Maguire,
• Conor P. Cullen,
• Georg S. Duesberg and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2020, 11, 1329–1335, doi:10.3762/bjnano.11.117

• study of the electrical performance of chemically synthesized monolayer molybdenum disulfide (MoS2) field-effect transistors irradiated with a focused helium ion beam as a function of increasing areal irradiation coverage. We determine an optimal coverage range of approx. 10%, which allows for the

• of well-performing monolayer TMD films [3][4][5], leading to viable large-scale integration of on-chip TMD FETs. With device miniaturization, it becomes key to understand the impact of defects such as chalcogen vacancies on the electrical transport properties of FETs based on 2D semiconductors. This

• exploration of nanometer-scale structural modifications of TMD devices [6][7][8]. The localized formation of defects by focused ion beam irradiation has been shown to induce unusual electronic properties in monolayer TMDs, such as pseudo-metallic phase transitions in MoS2 and WSe2 [9][10], resistive switching

Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

• Robby Reynaerts,
• Kunal S. Mali and
• Steven De Feyter

Beilstein J. Nanotechnol. 2020, 11, 1291–1302, doi:10.3762/bjnano.11.113

• solution–solid interface. One of the ways to influence network formation at this interface is to physically decouple the self-assembled monolayer from the underlying substrate thereby removing the influence of the substrate lattice, if any. Here we show a systematic exploration of self-assembly of a

• structure in which the alkane molecules are fully extended and are oriented at 90° with respect to the lamella axis. This monolayer structure is identical to that reported earlier [26]. After thoroughly understanding and optimization of the self-assembly behavior of BA-OC14 and n-C50 at the 1-phenyloctane

• when carried out using premixed solutions of the two components. Typically, a drop of 1 × 10−5 M solution of n-C50 was first applied onto a freshly cleaved HOPG surface and the surface was imaged using STM to ensure full coverage of the n-C50 monolayer. After this, a drop of BA-OC14 solution was

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• were performed in constant-current mode using an Omicron Scala SPM controller. All experiments were performed in the thermostatted environment (21.5 ± 0.5 °C) of the NanoLab Nijmegen. (a) Molecular structure of MnTUPCl. (b) Molecular structure of MnTUPOAc. (c) STM images of a monolayer of MnTUPCl at a

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 DBP molecules are well decoupled from the Ni(111) surface. Furthermore, a highly ordered DBP monolayer is obtained on h-BN/Ni(111) by depositing the molecules at a substrate temperature of 170 °C. The structural results are obtained by quantitative low-energy electron diffraction and low

• through different ways such as the usage of wide-band-gap insulator thin films (e.g., oxides, alkali halides) [3][4], a molecular spacer layer [5][6], or sp2-hybridized two-dimensional interlayers (e.g., graphene and hexagonal boron nitride (h-BN)) [7][8]. The advantageous properties of an h-BN monolayer

• on h-BN/Cu(111) were found recently [11][12]. This raises the question under which specific conditions an h-BN monolayer is sufficient to efficiently decouple organic molecules. Until now only a few publications exist which are concerned with this issue [13][14][15][16]. In this work we report on 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

• (Figure 1c) where one diagonal pair of phenyl groups would appear higher than the other. Such a configuration was indeed observed for a closed monolayer of C42H28 on Ag(100) [24]. However, it is difficult to infer geometric heights from STM images due to variations in the local density of states. Moreover

• similar superstructure with planar C42H28 backbones oriented parallel to the Au(111) surface was reported. In that work a multilayer C42H28 film was deposited at room temperature and subsequently annealed to achieve a monolayer coverage. Different superstructures of C42H28 with twisted and tilted

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• of decoupling layers made use of the in situ fabrication of single layers of transition metal dichalcogenides on metal surfaces. A monolayer of MoS2 on Au(111) provided very narrow molecular resonances, close to the thermal resolution limit at 4.6 K [26]. The exquisite decoupling efficiency has been

• properties of MoS2 on a metal surface are not the same as those of a free-standing monolayer. Both theory and experiment have found considerable hybridization of electronic states at the interface [29]. As a consequence, the bandgap is narrowed. Instead of the predicted bandgap of 2.8 eV of the free-standing

• vibronic states of the gas-phase molecule. Results and Discussion We have grown monolayer islands of MoS2 on an atomically clean Ag(111) surface, which had been exposed to sputtering–annealing cycles under ultrahigh vacuum before. The growth procedure was adapted from that of MoS2 on Au(111) [34][35], with

Highly sensitive detection of estradiol by a SERS sensor based on TiO₂ covered with gold nanoparticles

• Andrea Brognara,
• Ili F. Mohamad Ali Nasri,
• Beatrice R. Bricchi,
• Andrea Li Bassi,
• Caroline Gauchotte-Lindsay,
• Matteo Ghidelli and
• Nathalie Lidgi-Guigui

Beilstein J. Nanotechnol. 2020, 11, 1026–1035, doi:10.3762/bjnano.11.87

• spot, which we assume to be a single monolayer of MBA fully covering the surface [38][41]. From the SERS and Raman spectra of Figure 5 the EF values were calculated (Table 3). The sample that gave the most homogeneous EF through over the investigated wavelength range was TiO2/Au 6 nm deposited at 12 Pa

Key for crossing the BBB with nanoparticles: the rational design

• Sonia M. Lombardo,
• Marc Schneider,
• Akif E. Türeli and
• Nazende Günday Türeli

Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72

• brain endothelial cells) monolayer in vitro and exhibited a significantly higher accumulation in the brain than non-conjugated liposomes, showing the ability of this carrier system to cross the BBB. It was also shown that these particles could accumulate in the glioma cells and significantly increase

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• molecules into the Sn-down conformation was observed either after sample annealing at 200 °C or as a result of tip-induced manipulation. Room-temperature measurements conducted for a coverage of close to a monolayer showed no tendency for molecular arrangement. Keywords: rutile (110) surface; scanning

• intramolecular interactions lead to the stabilization of the layer at a coverage of close to 1 ML. The STM image of a monolayer of SnPc taken directly after deposition is presented in Figure 1a. Neither short- nor long-range order is observed. The adsorbed molecules are flat with the macrocycle lying parallel to

• conditions (78 K) as presented in Figure 2. Both types of SnPc molecules (with and without central protrusion) appear on the surface, as was observed for the non-annealed monolayer at room temperature (Figure 1a). Between the molecules, oxygen rows can be recognized (imaged as stripes in the [001] direction

Templating effect of single-layer graphene supported by an insulating substrate on the molecular orientation of lead phthalocyanine

• K. Priya Madhuri,
• Abhay A. Sagade,
• Pralay K. Santra and
• Neena S. John

Beilstein J. Nanotechnol. 2020, 11, 814–820, doi:10.3762/bjnano.11.66

• consider any influence of the underlying substrate on the MPc orientation. It has been shown that a monolayer of graphene, due to its extremely thin nature, exhibits transparency to the wetting behavior on substrates where van der Waals forces are the dominant surface–water interactions [14]. The wetting

• transparency disappears with an increasing number of graphene layers, and the wettability approaches that of graphite. The underlying support substrate is reported to even influence the chemical reactivity of a monolayer of graphene [15]. Most of the orientation studies of MPc on graphene deal with planar MPc

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• . From this analysis, phonon lifetime in the Raman active modes and phonon concentration, as correlated to the energy parameter E0, were calculated as a function of the laser power, P, and substrate temperature, T. For monolayer WSe2, from the power dependence it was determined that the phonon lifetime

• with increasing T and P; consequently, the phonon lifetime was found to decrease. Although phonon lifetime decreased with increasing temperature for all thicknesses, the decay rate in the phonon lifetime in the monolayer (1L) material was found to be 2× lower compared to the bulk. We invoke a harmonic

• variation with geometrical confinement in some TMDCs has been studied recently [7]. Monolayer (1L) TMDCs consist of a plane of a transition metal, M, sandwiched by chalcogenides, X, on either side to yield the stoichiometry MX2 [8]. The interlayer bonding in most ML TMDCs is through the weak van der Waals

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• was observed and no assignment was provided. The results of the SPEs from h-BN bulk seem to indicate these are different emitters from thin layers as described in the following. Monolayer and multilayers/flakes The first work showing SPE from multilayers and single-layer h-BN was published by Tran et

• complexes, it is shown they are low-energy formation defects in h-BN. This suggests that the assignment is presently controversial also considering the successive verification of SPEs as discussed in the following. In [45] h-BN exfoliated flakes, monolayer chemical vapor deposition (CVD) and in-house h-BN

• were studied. Here the correlations between material structural features and the location of SPEs from bulk down to the monolayer was studied at room temperature. Chemical etching and ion irradiation are used to generate the SPEs in h-BN various materials. Their photo-dynamics analysis reveals

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

• Mengdan Chen,
• Jinshu Zeng,
• Weiwei Ruan,
• Zhenghong Zhang,
• Yuhua Wang,
• Shusen Xie,
• Zhengchao Wang and
• Hongqin Yang

Beilstein J. Nanotechnol. 2020, 11, 568–582, doi:10.3762/bjnano.11.45

• %. The confluent monolayer was wounded using a sterilized 10 μL pipette tip, and then washed three times with PBS to remove dislodged cells. The culture medium was also changed to the serum-free medium. Pictures of the area of wound closure were taken with an inverted microscope. Then, the samples were

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• (e.g., dextran sulfate (DS), heparin and chitosan) and various synthetic polymers (e.g., PAH, PMA and poly(ethyleneimine) (PEI)). When a negatively charged template is dipped in a solution of positively charged PE, or vice versa, a monolayer of excessively adsorbed PEs is formed that leads to the

• reversal of the surface charge [3]. The coated templates are then rinsed and dipped in a solution of oppositely charged polymer; again, a monolayer deposition takes place but with the restoration of the original surface charge. The rinsing step becomes important, as it would otherwise lead to complex

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• density functional theory (DFT) study of the adsorption of small Cun (n = 1–4) structures on 2D MoS2 as a model system. We find on a perfect MoS2 monolayer that a single Cu atom prefers an adsorption site above the Mo atom. With increasing nanocluster size the nanocluster binds more strongly when Cu atoms

• adsorb atop the S atoms. Stability is driven by the number of Cu–Cu interactions and the distance between adsorption sites, with no obvious preference towards 2D or 3D structures. The introduction of a single S vacancy in the monolayer enhances the copper binding energy, although some Cun nanoclusters

• are actually unstable. The effect of the vacancy is localised around the vacancy site. Finally, on both the pristine and the defective MoS2 monolayer, the density-of-states analysis shows that the adsorption of Cu introduces new electronic states as a result of partial Cu oxidation, but the metallic

High-performance asymmetric supercapacitor made of NiMoO₄ nanorods@Co₃O₄ on a cellulose-based carbon aerogel

• Meixia Wang,
• Jing Zhang,
• Xibin Yi,
• Benxue Liu,
• Xinfu Zhao and
• Xiaochan Liu

Beilstein J. Nanotechnol. 2020, 11, 240–251, doi:10.3762/bjnano.11.18

• sample is characterized by a combination of type–IV and type–I isotherms, indicating the presence of micro- and mesopores with monolayer–multilayer adsorption. Furthermore, two distinct pore distribution curves are observed in the inset of Figure 5c revealing a hierarchical porosity: micro/mesopores

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• transport phenomena in a quantum dot coupled to pure monolayer graphene electrodes under external magnetic fields for finite on-site Coulomb interaction. The system is described by the pseudogap Anderson Hamiltonian. We use the equation of motion technique to determine the retarded Green’s function of the

• moment can be engineered by electrically controlling the properties of a transition metal adatom on graphene providing the possibility to develop graphene-based spintronic devices [56]. Therefore, the physical properties of a graphene monolayer with one of its carbon atoms substituted with a magnetic

• the Kondo effect for a carbon vacancy in a monolayer of graphene via an effective two-orbital single impurity model using the NRG approach [74]. Vojta et al. applied the pseudogap Kondo and Anderson models using a combination of analytical and numerical renormalization group approaches to study the

Rational design of block copolymer self-assemblies in photodynamic therapy

• Maxime Demazeau,
• Laure Gibot,
• Anne-Françoise Mingotaud,
• Patricia Vicendo,
• Clément Roux and
• Barbara Lonetti

Beilstein J. Nanotechnol. 2020, 11, 180–212, doi:10.3762/bjnano.11.15

Internalization mechanisms of cell-penetrating peptides

• Ivana Ruseska and
• Andreas Zimmer

Beilstein J. Nanotechnol. 2020, 11, 101–123, doi:10.3762/bjnano.11.10

• leads to the accumulation of the peptide on the outer leaflet of the membrane [28]. The peptides then cause bending of the lipid monolayer into the interior, forming a hydrophilic gap in the membrane, in which phospholipid heads and peptides are found. The transient pore formation models are in general

Antimony deposition onto Au(111) and insertion of Mg

• Lingxing Zan,
• Da Xing,
• Abdelaziz Ali Abd-El-Latif and
• Helmut Baltruschat

Beilstein J. Nanotechnol. 2019, 10, 2541–2552, doi:10.3762/bjnano.10.245

• processes are kinetically slow because of the large ionic radius and high charge density of Mg2+ compared with Li+. In this work, we prepared very thin films of Sb by electrodeposition on a Au(111) substrate. Monolayer and multilayer deposition (up to 20 monolayers) were characterized by cyclic voltammetry

• (CV) and scanning tunneling microscopy (STM). Monolayer deposition results in a characteristic row structure; the monolayer is commensurate in one dimension, but not in the other. The row structure is to some extent maintained after deposition of further layers. After dissolution of the Sb multilayers

• reduction of oxygenous Sb(III) species from bulk solution. The total charge density of peaks C1 and C2 (≈320 µC cm−2) suggests that the coverage of a monolayer is around 0.44 by assuming a one to one ratio of Sb to Au atoms for a hypothetical monolayer (and a 3e− process), which is close to the reported

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• the determination of mobilities in macroscopic samples. Keywords: conducting atomic force microscopy; lateral charge transport; nanografting; organic semiconductor; self-assembled monolayer; Introduction Charge transport in organic semiconductors plays a central role in the field of molecular

• performance of field effect transistor devices using pentacene as organic semiconductor [33]. In that work, the increase in performance was attributed to the reduced sheet resistance for charge transport in the anthracenethiol monolayer supporting the pentacene multilayer. In order to study the I–V

• in these two spectra are in accordance with the assumption of monolayer formation [26]. Note that a striking difference between the bulk and the PAT-SAM spectra is that the vibrational peaks at 942 cm−1 and 889–893 cm−1 for CH/CC vibrations of anthracene present in ATR spectra become a broad peak at

Multiwalled carbon nanotube based aromatic volatile organic compound sensor: sensitivity enhancement through 1-hexadecanethiol functionalisation

• Nadra Bohli,
• Meryem Belkilani,
• Juan Casanova-Chafer,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2019, 10, 2364–2373, doi:10.3762/bjnano.10.227

• temperature toluene and benzene sensor based on multiwall carbon nanotubes (MWCNTs) decorated with gold nanoparticles and functionalised with a long-chain thiol self-assembled monolayer, 1-hexadecanethiol (HDT). High-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared

• spectroscopy (FTIR) were performed to characterize the gold nanoparticle decoration and to examine the thiol monolayer bonding to the MWCNTs. The detection of aromatic vapours using Au-MWCNT and HDT/Au-MWCNT sensors down to the ppm range shows that the presence of the self-assembled layer increases the

• -assembled monolayer of 1-hexadecanethiol (HDT). The sensor functionalisation was undertaken through its immersion for 4 hours at room temperature in a solution of 5 mM of HDT diluted in ethanol. The sensor was then rinsed with ethanol to wash off the unbound thiol molecules and dried under a nitrogen stream

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

• Sabrina Barbosa de Souza Ferreira,
• Gustavo Braga,
• Évelin Lemos Oliveira,
• Jéssica Bassi da Silva,
• Hélen Cássia Rosseto,
• Lidiane Vizioli de Castro Hoshino,
• Mauro Luciano Baesso,
• Wilker Caetano,
• Craig Murdoch,
• Helen Elizabeth Colley and
• Marcos Luciano Bruschi

Beilstein J. Nanotechnol. 2019, 10, 2304–2328, doi:10.3762/bjnano.10.222

• incorporated into the formulation but decreased cytotoxic effects in healthy cells. Therefore, the nanostructured system demonstrated promising results due to the selectivity towards cancer cells in a monolayer cell culture in addition to exhibiting excellent physicochemical properties. Hence, further activity

Adsorption and desorption of self-assembled L-cysteine monolayers on nanoporous gold monitored by in situ resistometry

• Elisabeth Hengge,
• Eva-Maria Steyskal,
• Rupert Bachler,
• Alexander Dennig,
• Bernd Nidetzky and
• Roland Würschum

Beilstein J. Nanotechnol. 2019, 10, 2275–2279, doi:10.3762/bjnano.10.219

• resistometry. From the desorption peak related to the (111) surface of the structure, which is associated with a resistance change of 4.8%, an initial surface coverage of 0.48 monolayers of cysteine could be estimated. Keywords: L-cysteine; in situ resistometry; nanoporous gold; self-assembled monolayer (SAM

• literature, reporting a relative change in resistance of 6% for propanethiol and 22% for cysteamine monolayer assembly after 24 h [11]. In Figure 1, we can distinguish between three regimes of different slope (denoted as (I) to (III)). Regimes (I) and (III) can be correlated to stages in the adsorption

• literature to take 30 min for planar Au [7]. Regime (III) shows a very slow increase of the resistance, assigned to reordering of the monolayer, which is known to take several days [12]. After 72 h a total change between 17% and 18% is observed with a fading slope, which yet dropped to less than 1% in 2 days