Numerical analysis of vibration modes of a qPlus sensor with a long tip

• Kebei Chen,
• Zhenghui Liu,
• Yuchen Xie,
• Chunyu Zhang,
• Gengzhao Xu,
• Wentao Song and
• Ke Xu

Beilstein J. Nanotechnol. 2021, 12, 82–92, doi:10.3762/bjnano.12.7

• a diameter of 0.025 mm tip are shown in Figure 4. The grey dashed lines denote ftf. When the tip length is 0.5 mm, fq of the in-phase mode is very close to the dashed line (Figure 4a), which means that the tuning fork vibrates in resonance. When fq moves away from the dashed line and gets closer to

• ftip, the vibration of the qPlus sensor is mainly dominated by the tip, while the tuning fork hardly oscillates. The value of fq of the anti-phase mode is close to that of ftip for a 0.5 mm long tip (Figure 4b), resulting in tip resonance. As the tip length increases, fq gradually approaches ftf

• , leading to resonance of the tuning fork. If the tip length continues to increase, fq will be closer to the second-order ftip. The superposition vibration characteristics of the qPlus sensor are reflected in the amplitudes of the tuning fork and the tip, which will be discussed later. Amplitude of the

The role of gold atom concentration in the formation of Cu–Au nanoparticles from the gas phase

• Yuri Ya. Gafner,
• Svetlana L. Gafner,
• Darya A. Ryzkova and
• Andrey V. Nomoev

Beilstein J. Nanotechnol. 2021, 12, 72–81, doi:10.3762/bjnano.12.6

• this case, the energy and resonance line width depend on the percentage of copper. A Cu–Au nanoalloy is often produced using standard chemical methods. However, nanoparticles synthesized by these methods usually vary greatly in size, in the percentage of chemical elements, or in the structure formed

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

• Dorothee Silbernagl,
• Media Ghasem Zadeh Khorasani,
• Natalia Cano Murillo,
• Anna Maria Elert and
• Heinz Sturm

Beilstein J. Nanotechnol. 2021, 12, 58–71, doi:10.3762/bjnano.12.5

• range, <10 nm), and chemical forces (short range, <2 nm). By keeping the system in equilibrium (avoiding a snap onto the sample surface) the attractive forces at the surfaces are mapped, recording the change of resonance frequency due to the interacting attractive forces [23]. This method has not only

• ), according to: Bodies made from the same material show the highest attraction to each other, since the emitting field and the absorption by the oscillating dipoles are in resonance. Dissimilar materials attract each other less, which might even lead to repulsion. The attraction between two dissimilar

• nm. For high-resolution force spectroscopy an additional device was used in the AFM setup, an ImAFM (Intermodulation Products AB, Segersta, Sweden). The AFM probe used in this case was tip E (HQ: NSC35, Mikromasch, Wetzlar, Germany) with a resonance frequency f0 = 190 kHz, a spring constant kc = 12 N

ZnO and MXenes as electrode materials for supercapacitor devices

• Ameen Uddin Ammar,
• Ipek Deniz Yildirim,
• Feray Bakan and
• Emre Erdem

Beilstein J. Nanotechnol. 2021, 12, 49–57, doi:10.3762/bjnano.12.4

• environment of the lattice atoms and defects. With the aid of advanced characterization techniques one may get valuable information on site symmetry, atomic bonding, and, in particular, on the bandgap energy of semiconductors. Raman, photoluminescence (PL), UV–vis, and electron paramagnetic resonance (EPR

• the major defect centers and give an EPR signal around g ≈ 1.96 [2][3][4][5]. Compared to ge ≈ 2.0023, this resonance requires a higher magnetic field and, thus, a higher microwave frequency. In other words, higher microwave and Zeeman energy are required for this kind of allowed electronic transition

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

• resonances with effective spin, valley, or spin–valley fluctuations, the emergence of an exotic SU(3) Kondo resonance is foreseen even without mixing between shells or valleys, but simply due to the peculiarity of the band structure and a subtle interplay of magnetic field, spin–orbit interaction, and

• moments are quenched. The SU(3) Kondo effect is caused by cotunneling-induced fluctuations of |0↓⟩, |0↑⟩, and |↓0⟩ states and the resulting resonance is spin- and orbital-polarized. SU(4) Kondo screening results from effective fluctuations of all four spin–orbital states |ls⟩. In the 2e valley, we observe

• resonance, in this case, is centered at EF. For gate-voltage intervals in which Kondo correlations are destroyed a drop of conductance is observed. We also present examples of partial conductances for two values of SO coupling δ = 0.5 meV·nm, for which the SU(4) point is located in the 2e valley and δ = 1

Application of contact-resonance AFM methods to polymer samples

• Sebastian Friedrich and
• Brunero Cappella

Beilstein J. Nanotechnol. 2020, 11, 1714–1727, doi:10.3762/bjnano.11.154

• Sebastian Friedrich Brunero Cappella Federal Institute for Material Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany 10.3762/bjnano.11.154 Abstract Contact-resonance AFM (CR-AFM) has been used in recent years for the measurement of mechanical properties of rather stiff

• . Keywords: atomic force microscopy; contact resonance; mechanical properties; polymers; wear; Introduction The development of new materials for applications on the nanoscale, such as thin polymer films, demands a reliable determination of their mechanical properties. Atomic force microscopy (AFM) is a very

• phase image. The resulting contrast is, however, hard to analyze quantitatively. Contact-resonance AFM (CR-AFM) [4][5] is a dynamic contact technique that makes use of the vibrational behavior of the cantilever while the tip is in permanent contact with the sample. Generally, an increase in sample

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

• and the substrate occurs due to the chemisorptive bonding, which leads to a change in the polarizability of the molecule and thus to an enhancement of the Raman signal. It is also possible that electronic excitations of the adsorbed molecule allow for a resonance Raman effect, which causes an

• eV. Hence, a resonance was considered less probable, yielding no enhancement of Raman modes. This model should evidently encompass that the coupling to the SPPs requires a rough surface or local protrusions on the surface due to defects that break the translational symmetry. For comparison, we note

Cu₂O nanoparticles for the degradation of methyl parathion

• Juan Rizo,
• David Díaz,
• Benito Reyes-Trejo and
• M. Josefina Arellano-Jiménez

Beilstein J. Nanotechnol. 2020, 11, 1546–1555, doi:10.3762/bjnano.11.137

• different NPs sizes (16, 29 and 45 nm), determined with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM), were synthesized using a modified Benedict’s reagent. 1H nuclear magnetic resonance (NMR) results show that the hydrolytic degradation of MP leads to the formation of

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

• large surface charge oscillations on the opposite surfaces confining the gap, and a field in the gap that is enhanced by several orders of magnitude with respect to the incident field [27]. The gap field is particularly strong when the particle plasmons are in resonance. The enhanced local field and the

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

• modeling the cantilevers based on Timoshenko beam theory, the geometrical dimensions such as length, base width, leg width and thickness are studied. By finding the static properties (mass, spring constants) and dynamic properties (resonance frequencies and quality factors) for different geometrical

• -pass measurement [1]. In bimodal AFM, the first eigenmode is excited at or near the resonance frequency (reserved for topography measurements) while the second eigenmode is in open-loop capturing material composition via phase shift of the second eigenmode. Due to its unique capabilities

• . Bushan stated that the cantilever stylus used in the AFM should have properties such as low normal spring constant, high resonance frequency, high quality factor, high lateral spring constant, and short cantilever length [12]. V-shaped cantilevers have a unique set of properties, that is, low normal

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

• self-resonance frequency of about 20 GHz were used for gate and drain power supply circuits. All passive components, for example, microwave capacitors, coils, and precision resistors were measured before at liquid helium temperature for obtaining the spread of nominal parameters. The amplifier was

• noise figure corresponded to 2.1 dB with a gain value of about 40 dB for the frequency range from 6 to 13 GHz. The transmission |S21| of the sample was measured and the resonance frequencies of resonators were defined in the frequency spectrum from 6 to 9 GHz. We defined a resonator fundamental

• corresponds to a normalized maximum transmission. Due to the magnetic flux quantization the qubit characteristic has periodic behavior. The maximum shift of the resonance frequency corresponds to a so called “sweet spot” and the distance between two sweet spots corresponds to the magnetic flux quantum Φ0. We

On the frequency dependence of viscoelastic material characterization with intermittent-contact dynamic atomic force microscopy: avoiding mischaracterization across large frequency ranges

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 1409–1418, doi:10.3762/bjnano.11.125

• response of the cantilever with respect to the excitation, within amplitude-modulation AFM (AM-AFM)), which generally yields high-contrast images for dissipative materials [22]. Dynamic contact-mode techniques such as contact-resonance AFM [11][12][13][28], dual-amplitude resonance tracking AFM (DART [10

• -static force spectroscopy (i.e., using force–distance curves acquired at frequencies much lower than the resonance frequency of the cantilever). Specifically, we have introduced a methodology based on the Generalized Voigt (Kelvin) or Maxwell viscoelastic model (Figure 1), including an arbitrary number

• described in Figure 2 and Table 1, when imaged with a soft tapping-mode cantilever. For this we used a resonance frequency of 70 kHz, a relatively low force constant of 0.5 N/m, considering the softness of the materials under study, and a free oscillation amplitude of 50 nm (the Experimental section below

Transient coating of γ-Fe₂O₃ nanoparticles with glutamate for its delivery to and removal from brain nerve terminals

• Konstantin Paliienko,
• Artem Pastukhov,
• Michal Babič,
• Daniel Horák,
• Olga Vasylchenko and
• Tatiana Borisova

Beilstein J. Nanotechnol. 2020, 11, 1381–1393, doi:10.3762/bjnano.11.122

• due to their magnetism and chemical stability [9][10][11][12][13]. Among a variety of other nanoparticles, superparamagnetic iron oxide nanoparticles are used for magnetic resonance imaging in cancer theranostics and magnetic hyperthermia [9][10][11][14]. Controlled magnetic fields can lead to induced

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

• contrast to the monolayers of PEN and PFP on graphite, with a likewise lying-down orientation and large differences in the HOMO positions [11][25][26]. In general, for a strong interfacial coupling and charge transfer, the resonance structure of the adsorbate in the monolayer can be notably different from

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• ) and a stick–slip controller (8742-4 PicomotorTM drive, Newport Corporation). The AFM can operate in contact mode and in an off-resonance mode based on force–distance curves [24]. In this off-resonance mode, which we refer to as off-resonance tapping (ORT), the cantilever is moved sinusoidally up and

• very slow in vacuum [29]. In ORT, the tapping rate is a least one order of magnitude below the first resonance of the cantilever and hence the enhancement of the Q-factor in vacuum is less detrimental to the achievable scan speed. Results The system has been experimentally tested on a variety of sample

• surfaces in contact and off-resonance imaging modes, demonstrating the feasibility of the integration through a series of three experiments. Correlative AFM and HIM imaging is demonstrated in Figure 2 by imaging silicon nanopillars [30]. The HIM offers a large field of view, which allows for the cantilever

Magnetic-field-assisted synthesis of anisotropic iron oxide particles: Effect of pH

• Andrey V. Shibaev,
• Petr V. Shvets,
• Darya E. Kessel,
• Roman A. Kamyshinsky,
• Anton S. Orekhov,
• Sergey S. Abramchuk,
• Alexei R. Khokhlov and
• Olga E. Philippova

Beilstein J. Nanotechnol. 2020, 11, 1230–1241, doi:10.3762/bjnano.11.107

• environmental benigness [4][5][6][7][8]. These nanomaterials can be exploited in a variety of applications, including magnetic data storage [9], magnetic resonance imaging (MRI) [6][10][11][12], hyperthermia [6][13][14][15], magnetic separation [16], targeted drug delivery [6][16][17][18][19], lithium-ion

High permittivity, breakdown strength, and energy storage density of polythiophene-encapsulated BaTiO₃ nanoparticles

• Adnanullah Khan,
• Amir Habib and
• Adeel Afzal

Beilstein J. Nanotechnol. 2020, 11, 1190–1197, doi:10.3762/bjnano.11.103

• resonance absorption between two thiophene rings [17]. It demonstrates that PTh is predominantly formed by Cα–Cα conjunction during the low-temperature oxidative polymerization. The transmittance peaks at 1035 cm−1 and 788 cm−1 further prove this point as they indicate the out-of-plane bending (τCβ–H) and

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

• embedded in a molecular island. The spectroscopic signatures of HOMO and LUMO are visible at, respectively, approx. −0.87 and approx. 0.92 V. The molecular resonance widths are smaller than those observed on the other surfaces; in particular, the LUMO exhibits a narrow line shape. Before analyzing the

• energy since the HOMO resonance essentially retains its energy at approx. −0.87 eV. Assuming that C42H28 is weakly coupled to the substrate, its orbital energies are expected to be aligned with the vacuum level [46] and, thus, susceptible to local changes in the work function. Site-specific work

• adjacent molecules. A finite adsorbate–substrate interaction is reflected by the presence of a molecular superstructure that matches the period of the Au(111) reconstruction. However, the HOMO resonance width has decreased by a factor of three compared to its width on Pt(111). Even vibronic progression due

Photothermally active nanoparticles as a promising tool for eliminating bacteria and biofilms

• Mykola Borzenkov,
• Piersandro Pallavicini,
• Angelo Taglietti,
• Laura D’Alfonso,
• Maddalena Collini and
• Giuseppe Chirico

Beilstein J. Nanotechnol. 2020, 11, 1134–1146, doi:10.3762/bjnano.11.98

• gold nanoparticle aggregation was implemented [54]. According to this strategy, the spherical nanoparticles, with a typical localized surface plasmon resonance (LSPR) absorption at 520 nm, aggregated in situ at the surface of the bacterial membrane. The gold nanoparticle aggregation induced a change in

• photothermal effect under NIR laser irradiation. Carbon nanotubes are another valuable class of nanomaterials. They have high photothermal efficiency under NIR irradiation which excites the longitudinal phonon resonance along the nanotube. The resonance peaks can be tuned by changing the tube length [86

Straightforward synthesis of gold nanoparticles by adding water to an engineered small dendrimer

• Sébastien Gottis,
• Régis Laurent,
• Vincent Collière and
• Anne-Marie Caminade

Beilstein J. Nanotechnol. 2020, 11, 1110–1118, doi:10.3762/bjnano.11.95

• to the P=S group in the 31P nuclear magnetic resonance (NMR) spectra (Figure 1 and Table 1). Indeed, this signal shifted from 52.1 ppm in 1 to 33.7 ppm in 2 (Δδ = −18.4 ppm). The attempts to generate the gold nanoparticles from compound 2 were carried out by adding water. This compound was not very

• gold nanoparticles since this color corresponds to the surface plasmon resonance wavelength. This is a well-known phenomenon observed in gold nanoparticles [56]. Considering that the gold nanoparticles are spherical, the maximum intensity of the visible spectrum at 545 nm should correspond to a mean

• size of ≈50 nm for the gold nanoparticles [57][58]. The shoulder detected at ≈630 nm corresponds to the longitudinal surface plasmon resonance, and it is characteristic of the presence of non-spherical gold NPs, in particular rod-like or triangular NPs [59][60]. The presence of this shoulder shifted

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• magnetic resonance imaging (MRI) (for more on this topic consult [11][12][13][14]). Among the abovementioned nanoscience products, iron oxide nanoparticles, especially superparamagnetic iron oxide nanoparticles (SPIONs) hold a lot of promise in many domains, not only regarding biology [15]. SPIONs consist

• of 2000–2019. Review Benefits of SPIONs or what makes SPIONs such a promising aspect for therapeutics and adjunct treatments Firstly, certain SPIONs are already clinically approved for magnetic resonance imaging (MRI) [24][25][26]. For this application, SPIONs have been functionalized with dextran

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

• character, this choice will allow us to detect a negative ion resonance within the bandgap of MoS2. We will show that the LUMO is indeed decoupled from the metallic substrate as we can detect a narrow line width followed by a satellite structure. We can reproduce this fine structure by simulating the

• spectra on top of the molecules (Figure 4b). These show two main resonances at approx. 0.47 V and approx. 0.64 V. Another peak at approx. 1.3 V matches the Γ resonance of the bare MoS2 layer. At negative bias voltage, we observe an onset of conductance at approx. −1.8 V. The dI/dV spectra thus show that

• 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

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

• µM, 100 µM, and 1 mM. Samples were left in the E2 solutions for 1 h before being rinsed with RO water and blown dry. Figure 1 gives a schematic of the final system. Optical and SERS measurements Plasmon resonance was evaluated via optical spectroscopy. For this purpose, transmission spectra were

• became sharper and blue-shifted, which can be attributed to the formation of Au NPs. In the annealed samples the LSP resonance (LSPR) red-shifted as a function of the Au NP size, i.e., the wavelength for maximum absorption varied from 549 nm (for the 12 Pa sample with 3 nm of Au) up to a maximum value of

Uniform Fe₃O₄/Gd₂O₃-DHCA nanocubes for dual-mode magnetic resonance imaging

• Miao Qin,
• Yueyou Peng,
• Mengjie Xu,
• Hui Yan,
• Yizhu Cheng,
• Xiumei Zhang,
• Di Huang,
• Weiyi Chen and
• Yanfeng Meng

Beilstein J. Nanotechnol. 2020, 11, 1000–1009, doi:10.3762/bjnano.11.84

• multimodal magnetic resonance imaging (MRI) technique has been extensively studied over the past few years since it offers complementary information that can increase diagnostic accuracy. Simple methods to synthesize contrast agents are necessary for the development of multimodal MRI. Herein, uniformly

• -dihydroxyhydrocinnamic acid (DHCA); dual-mode imaging; Fe3O4/Gd2O3-DHCA nanocubes; gadolinium oxide (Gd2O3); iron(II,III) oxide (Fe3O4); magnetic resonance imaging (MRI); Introduction Magnetic resonance imaging (MRI) is a noninvasive technique that has been broadly used in the clinical field to assist in disease

• until the solution was clear and transparent. After that, the solution was diluted in 10 mL of ultrapure water and finally could be used for testing. In vitro and in vivo magnetic resonance images were captured by a 3.0 T MRI scanner (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

• Vadim Morari,
• Aida Pantazi,
• Nicolai Curmei,
• Vitalie Postolache,
• Emil V. Rusu,
• Marius Enachescu,
• Ion M. Tiginyanu and
• Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

• about 400 meV. One can see from Figure 4 and Figure 5 that narrow emission lines related to resonance Raman scattering (RRS) are present in the emission spectrum from the ZnMgO films in addition to the broad PL bands, which is indicative of the high optical properties of the films produced by sol–gel

• spin coating. RRS from solids can be observed if the energy of the incoming or scattered photons matches real electronic states in the material. One refers to incoming and outgoing resonance, respectively [38][45][46][47]. Taking into account the band gap value and the width of band tails in ZnMgO thin

• summarized PL band maximum in Zn1−xMgxO films. The conditions of resonance Raman scattering in ZnMgO films for various compositions and temperatures. Funding The following sources of funding are acknowledged: National Agency for Research and Development of the Republic of Moldova (Grant No