Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells

• Cynthia Kembuan,
• Helena Oliveira and
• Christina Graf

Beilstein J. Nanotechnol. 2021, 12, 35–48, doi:10.3762/bjnano.12.3

• -coated UCNPs on RAW 264.7 macrophages, an analysis of the cell cycle dynamics of UCNP@thin_NH2 and UCNP@thick_NH2 samples was carried out. The cell cycle consists of four parts: The rest phase (G0); the first gap phase (G1), in which the cells grow and produce enzymes necessary for cell division; the

• synthesis phase (S), in which the DNA is replicated; and the second gap phase (G2), in which the cell continues to grow further and to perform processes that are necessary for mitosis [74]. Both silica-coated samples show a significant increase in the G0/G1 phase compared to control cells (not treated with

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• prediction, one third of randomly selected nanotubes should be metallic. Experimentally, the fraction of nanotubes showing metallic behavior is very small (≤1% [41]). Even in nominally metallic tubes a narrow gap of the order of 10 meV is usually observed. These systems are sometimes called “nearly metallic

• equilibrium energy gap is 37 meV·nm2 [9][63]. ΔO and ΔZ stand for orbital and Zeeman parameters of spin–orbit coupling in the form: where sz is the spin component along the nanotube axis and lx is the Pauli matrix in the A–B graphene sublattice space. ΔZ = −δcos(3Θ)/D and ΔO = δ/D [63]. Various theoretical

• ⟩ degenerate in a magnetic field of Bo = |Δe|/μo ≈ 0.48 T. In small-bandgap nanotubes, the field dependencies of degeneracy lines are determined not only by spin–orbit parameters and orbital and spin magnetic moments, but also by the gap and the gate voltage. This is reflected in the nonlinear gate

Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector

• Eduardo Serralta,
• Nico Klingner,
• Olivier De Castro,
• Michael Mousley,
• Santhana Eswara,
• Serge Duarte Pinto,
• Tom Wirtz and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2020, 11, 1854–1864, doi:10.3762/bjnano.11.167

• future ToF applications. In the present form of the detector, we use two MCPs, each with a 50 mm by 50 mm square active area, stacked and rotated by 90° to each other with a gap of 100 μm between them. The first MCP has a magnesium oxide coating to increase the SE yield [37]. The MCP pores have a

Self-standing heterostructured NiC_x-NiFe-NC/biochar as a highly efficient cathode for lithium–oxygen batteries

• Shengyu Jing,
• Xu Gong,
• Shan Ji,
• Linhui Jia,
• Bruno G. Pollet,
• Sheng Yan and
• Huagen Liang

Beilstein J. Nanotechnol. 2020, 11, 1809–1821, doi:10.3762/bjnano.11.163

• that the overpotential of NiFe-PBA/PP-900 in the Li–O2 cell was comparable to data reported in the literature, as shown in Table 1. An ideal Li–O2 cell has a low charge voltage plateau and a high discharge voltage plateau. The gap between charge and discharge voltage plateaus of the Li–O2 battery with

High-responsivity hybrid α-Ag₂S/Si photodetector prepared by pulsed laser ablation in liquid

• Raid A. Ismail,
• Hanan A. Rawdhan and
• Duha S. Ahmed

Beilstein J. Nanotechnol. 2020, 11, 1596–1607, doi:10.3762/bjnano.11.142

• (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV–vis spectroscopy. The optical absorption decreased and the optical energy gap of α-Ag2S increased from 1.5 to 2 eV after the CTAB surfactant was added to the Tu solution. XRD studies revealed that the synthesized Ag2S NPs were polycrystalline

• narrow direct optical energy gap, which ranges from 0.96 to 1.1 eV at room temperature. Ag2S has good chemical stability, low toxicity, and high optical absorption [4]. According to the growth temperature, Ag2S has three phases: monoclinic α-Ag2S (acanthite), β-Ag2S (argentite), and the stable γ-Ag2S [5

• with CTAB due to quantum size effects [31]. The absorption of the Ag2S NPs decreased sharply above λ = 302 nm for Ag2S prepared in pure Tu solution, while it decreased slowly for Ag2S prepared in Tu with CTAB, indicating different absorption edges. The optical band gap of the Ag2S NPs prepared in pure

Detecting stable adsorbates of (1S)-camphor on Cu(111) with Bayesian optimization

• Jari Järvi,
• Patrick Rinke and
• Milica Todorović

Beilstein J. Nanotechnol. 2020, 11, 1577–1589, doi:10.3762/bjnano.11.140

• resemble the HOMO and LUMO of an isolated camphor molecule and are at −1.0 and 2.9 eV, respectively, with an energy gap of 3.9 eV. This indicates physisorption between the molecule and the substrate in class Hy. Discussion With the low-dimensional studies of molecular translation (1D and 2D) and rotation

Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• factor of R6G molecules on the pyramid structure was about 105. Wu et al. [26] machined nanohole array structures using EBL and lift-off methods. The diameter of the nanoholes ranged from 90 to 585 nm, and the gap between adjacent nanoholes ranged from 125 to 585 nm. An enhancement factor of 8 × 106 was

• ] manufactured graphene/Au nanodot array structures, which were used as SERS substrates. The diameter and gap distribution ranged from 30 to 42 nm and from 20 to 30 nm, respectively. In addition, a detection level of 10−9 mol·L−1 for R6G molecules was obtained using the aforementioned SERS substrates. Choi et al

Optically and electrically driven nanoantennas

• Monika Fleischer,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2020, 11, 1542–1545, doi:10.3762/bjnano.11.136

• , Germany 10.3762/bjnano.11.136 Keywords: active plasmonics; electrically driven nanoantenna; gap antenna; nanoantenna; nanofabrication; nanospectroscopy; nano-photonics; optical antenna; second harmonic generation; sensing; scanning tip; surface-enhanced infrared absorption (SEIRA); surface-enhanced Raman

• frequencies to a traveling electromagnetic wave that can be observed in the far field. Optical antennas are key elements in nano-optics, bridging the gap between the dimension of an optical wavelength (several hundreds of nanometers) and the size of elementary quantum emitters such as single atoms, molecules

• integration, device-to-device communication, and bilateral transduction between electrons and photons [26]. An optical gap antenna typically consists of two nanostructures with a nanometer gap in between. Optical excitation induces a coupled plasmon oscillation along the two antenna parts, which can lead to

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

• Mehrnoosh Damircheli and
• Babak Eslami

Beilstein J. Nanotechnol. 2020, 11, 1525–1541, doi:10.3762/bjnano.11.135

• carried out at a setpoint around 60%, the tip–sample gap has been always higher that than the intermolecular distance causing the net forces to be attractive. Different tip–sample gaps can change the energies of the cantilever in different eigenmodes for bimodal AFM imaging. This can consequently affect

Helium ion microscope – secondary ion mass spectrometry for geological materials

• Matthew R. Ball,
• Richard J. M. Taylor,
• Joshua F. Einsle,
• Fouzia Khanom,
• Christelle Guillermier and
• Richard J. Harrison

Beilstein J. Nanotechnol. 2020, 11, 1504–1515, doi:10.3762/bjnano.11.133

• fill a critical length-scale gap in the field of microanalysis, with resolutions second only to the atom probe, but with field of views of the order of micrometres, allowing for high resolution over a relatively large sample area. The HIM–SIMS is therefore a useful tool for a wide range of geological

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

• and below the Fermi level, with a large gap between a singly occupied molecular orbital (SOMO) and a singly unoccupied molecular orbital (SUMO). In addition, PT confirms an integer charge transfer, which would be expected to result from tunneling [15]. However, using the ability to tune the MgO(100

• results. On some preparations, no molecular emissions were observed in the MgO bandgap, whereas on others, distinctive features appeared in the gap at 0.5 and 2.5 eV below the Fermi level. The momentum maps of these molecular emissions (Figure 3) can be unambiguously assigned to the orbitals and the

• , indicated by the crosses in Figure 3, are displayed in Figure 4b. For ΦMgO greater than 2.8 eV, no significant orbital emissions are found in the gap, implying that no charged molecules are present on the surface. For ΦMgO below 2.8 eV, molecular emissions arise at 2.52 and 0.55 eV with respect to EF. Their

A wideband cryogenic microwave low-noise amplifier

• Boris I. Ivanov,
• Dmitri I. Volkhin,
• Ilya L. Novikov,
• Dmitri K. Pitsun,
• Dmitri O. Moskalev,
• Ilya A. Rodionov,
• Evgeni Il’ichev and
• Aleksey G. Vostretsov

Beilstein J. Nanotechnol. 2020, 11, 1484–1491, doi:10.3762/bjnano.11.131

• minimum qubit energy gap of Δ = 6.625 GHz. The qubit spectrum as a function of the current is shown in Figure 7. Here, the transition |g⟩–|e⟩ is shown. Conclusion The characteristics of a low-noise cryogenic microwave amplifier and the measurement of a superconducting X-mon qubit are shown. The amplifier

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

• . Scanning tunneling microscopy (STM) and spectroscopy (STS) measurements of the pyrene derivatives adsorbed on a Cu(111)-supported hexagonal boron nitride (hBN) decoupling layer provided access to spatially and energetically resolved molecular electronic states. We demonstrate that the pyrene electronic gap

• experiments, the photophysical characterization in solution, and the DFT modeling (in vacuum and with toluene solvation) evidence a reduction of the molecular gap when proceeding from di- to tetrasubstituted pyrene derivatives, but with effects that are different depending on the chemical surrounding. Results

• that governed the shrinking of the HOMO–LUMO gap upon the derivatization with pyridin-4-ylethynyl groups. The picture of the orbital interactions was similar in the di- and tetrapyrenyl derivatives, with the HOMO–LUMO gap being influenced mostly by the number of substituents. The molecular gap of the

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• from light irradiation to excite and mobilize an electron from the valence band to the conduction band, leaving a highly reactive gap (H+). This zone becomes a ROS source as it interacts with H2O or OH− that surrounds the nanoparticles [152]. In addition to molecules such as ascorbic acid, carotene

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

• to EF (marked with an asterisk) could be ascribed to a charge transfer from the substrate [28]. The transport gap of PEN is 2.20 eV [88]. Similar transport gaps can be expected for PFP and F4PEN, which puts the Fermi level rather close to the LUMO. Moreover, in the vicinity of a metal surface, the

• gap has been found to decrease, and the molecular energy levels become broadened [1][89][90], which is expected to promote the charge transfer to the LUMO [7][8]. The positions of the HOMO levels of molecular monolayers on metal substrates depend also on the magnitude of the above mentioned screening

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

• ], NaCl [40], CuN [41] and oxides [32][42] have been used. Typically, the ultrathin films of these wide band gap materials act as insulating layers while still allowing electron tunneling through them. Chemisorbed iodine layers have been used as passivating layers on metals such as Au for achieving

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• fill in this gap, this study presents a numerical simulation model that elucidates how the nanoparticle coating affects the nanoparticle agglomeration tendency as well as the effective magnetic relaxation time of the system. To simulate the self-organization of the colloidal nanoparticles, a stochastic

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• result is radically different from the data obtained for graphene/SiO2 [33]. In addition, hBN monolayers exhibit a high temperature stability, a low dielectric constant (ε = 3–4), and a high thermal conductivity [34]. The band gap of hBN is about 5.9 eV [35]. Furthermore, which is also important, hBN is

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

• with the bands of the metal substrate, which results in changes of the intrinsic optical and electronic properties of the adsorbed molecule. This process is referred to as hybridization, which may be accompanied by the reduction of the HOMO–LUMO gap, the change of the energy-level alignment, and even

• 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 metal single crystals are the high crystal quality, chemical inertness and the wide band gap of approx. 6 eV, which apparently renders h-BN a promising candidate for the decoupling of highly ordered molecular films [9][10]. However, indications for a significant hybridization of organic molecules

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

• ) [18][19], while Au(111) is characterized by a surface-projected gap of sp-derived electron states [20]. Graphene on Pt(111) exhibits a considerable distance of 330 pm from the metal surface [21], which implies a weak graphene–metal hybridization. Adsorbates on graphene-covered Pt(111) are therefore

• signature up to 2 V. Both spectra do not exhibit a clear-cut gap region, i.e., a bias voltage range with nearly vanishing dI/dV signal. These observations reflect the strong hybridization of C42H28 with the Pt(111) surface and hamper the meaningful determination of a HOMO–LUMO gap width. Moreover, the

• lifetime of electrons injected into the LUMO [39]. Due to the absence of peaked orbital signatures a HOMO–LUMO gap width is hard to estimate. In a previous report, constant-current dI/dV data were presented for C42H28 on Au(111) and a HOMO–LUMO gap exceeding 3 eV was extracted [25]. A direct comparison to

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• beam. The near field localized at the tip apex enhances the optical field in the tip–sample gap by several orders of magnitude and simultaneously directs the emitted photons from the gap into the far field for detection. With recent demonstrations of a spatial resolution even at the angstrom level [25

• gap between the gold tip and the SiNW. A more quantitative investigation of the polarization angle-resolved emission patterns in Figure 6 will be further pursued. The results shown in Figure 4 and Figure 6 demonstrate that it is possible to combine the polarization angle-resolved experiments with a

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

• moiré pattern bears a topographic and an electronic modulation [38], we investigate the differential conductance (dI/dV) spectra on different locations (Figure 1d). We first examine the spectrum on the top site of the moiré structure. We observe a gap in the density of states, which is flanked by an

• the STM image in Figure 4a was recorded within the energy gap of the molecule, which explains the featureless shape. In order to determine the origin of each of the resonances, we recorded constant-height dI/dV maps at their corresponding energies (Figure 5). For the first resonance at positive bias

• essentially shows the same elliptical shapes of the molecules as the STM image recorded in the electronic gap (Figure 4a). Our DFT calculations suggest that the next higher unoccupied orbitals lie 3 eV above the LUMO and show a pattern of nodal planes that are absent in the experiment. Additionally, given the

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• , may be associated with the Dember effect. The photoconductivity and photo-EMF spectra in the absorption edge region show a broad band with maximum values at 1.187 eV (Е⟂с) and 1.167 eV (Е||с) (Figure 3A) which are associated with the light absorption at the direct transitions in the interband gap

• and it does not refute the existence of indirect transitions given that more studies (like the ones made for Ge, Si, GaP, etc.) need to be performed in order to clarify those issues, ideally with purely grown crystals. We do not negate the existence of indirect transitions as we do not have such

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• particular, photodetectors based on graphene will have a large dark current due to the conductivity of graphene even without incident photons [2]. An energy gap in the band structure of graphene can be created using quantum confinement effects via creating graphene nanoribbons (GNRs) with a width of

• integer). This form of classification is based on the relation between the magnitude of the energy gap and the width of the AGNRs. The quantum confinement effect alters the bandgap energy in these nanostructures, which decreases with the increase of AGNR width (within each group). A comparison of the

• bandgap of the two structures, i.e., 7-AGNR and 8-AGNR with bandgap energies of 1.47 eV and 0.22 eV, respectively, shows that the bandgap depends on the dimer number or width of the nanoribbons. In other words, the addition of only one row of carbon atoms alters the energy gap about by 1.25 eV. We also

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an

• Following the line proposed in [4], an aluminium Al/AlOx/Al tunnel junction 0.4 × 2 µm2 was fabricated using a self-aligned shadow evaporation technique. Its current–voltage characteristic shown in the inset of Figure 1 (see below) has a well-defined hysteresis. The double voltage gap of the junction is

• excitation caused by a rapid decrease in the barrier, and remained constant until the appearance of a gap voltage due to thermal noise or quantum tunneling. The lifetime measurements were repeated at least 200 times for each value of the bias current. For a high-frequency experiment, a microwave signal was