Cantilever signature of tip detachment during contact resonance AFM

• Devin Kalafut,
• Ryan Wagner,
• Maria Jose Cadena,
• Anil Bajaj and
• Arvind Raman

Beilstein J. Nanotechnol. 2021, 12, 1286–1296, doi:10.3762/bjnano.12.96

• Devin Kalafut Ryan Wagner Maria Jose Cadena Anil Bajaj Arvind Raman School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA 10.3762/bjnano.12.96 Abstract Contact resonance atomic force microscopy, piezoresponse force microscopy, and electrochemical strain microscopy are

• connect the qualitative and quantitative behavior to experimental features. Keywords: atomic force microscopy (AFM); contact resonance; nonlinear normal mode (NNM); tip–sample detachment; photothermal excitation; Introduction Contact resonance atomic force microscopy (CR-AFM) [1][2], piezoresponse force

• experimental measurements in Figure 1a reveal interesting features in the dynamic behavior of the cantilever as it is driven by increasing the harmonic excitation amplitude. At the lowest drive amplitude, the response amplitude frequency sweep displays linear behavior, that is, a symmetric resonance peak over

Plasmon-enhanced photoluminescence from TiO₂ and TeO₂ thin films doped by Eu³⁺ for optoelectronic applications

• Marcin Łapiński,
• Jakub Czubek,
• Katarzyna Drozdowska,
• Anna Synak,
• Wojciech Sadowski and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2021, 12, 1271–1278, doi:10.3762/bjnano.12.94

• candidates as phosphors in white LEDs. Keywords: gold nanostructures; luminescence; plasmon resonance; Introduction The rapid development of optoelectronics leads to challenges in the search for new luminescence materials. Especially the fabrication of white LEDs requires more efficient phosphors

• . Potential new materials can be found through the computation of luminescent thin films and plasmonic platforms. Such a hybrid structure can be formed by thin oxide layers doped with rare-earth ions deposited on metal nanostructures [1][2][3]. Plasmonic resonance can be observed in metallic nanostructures

• , so-called plasmonic platforms, and thin films. Among different plasmonic materials, gold nanostructures exhibit resonance in the visible range and have been extensively studied as a material for light absorption and emission improvement [4][5][6][7][8]. Titanium dioxide seems to be one of the most

Two dynamic modes to streamline challenging atomic force microscopy measurements

• Alexei G. Temiryazev,
• Andrey V. Krayev and
• Marina P. Temiryazeva

Beilstein J. Nanotechnol. 2021, 12, 1226–1236, doi:10.3762/bjnano.12.90

• interaction of the probe with the sample is used in off-resonance dynamic modes [6]. Although they have various names, depending on the specific manufacturer (PeakForce Tapping, Hybrid Mode, Digital Pulsed Force Mode), a common feature of these methods is that the transition to the contact is carried out

• classical contact mode, the friction force can be measured; when using off-resonance dynamic modes, stiffness and adhesion in the samples can be determined. Obviously, in determining the mechanical properties, the force of tip–surface interaction should be somewhat greater than that required if the task is

• strictly limited to the measurement of topography. When scanning in air, the interaction of the tip with the sample can be reduced, and the measurements themselves are performed more delicately when using resonance modes. In this class of AFM techniques, the probe is forced to oscillate close to its

Impact of electron–phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime

• Patryk Florków and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2021, 12, 1209–1225, doi:10.3762/bjnano.12.89

• the coherent superposition of cotunneling processes. The latter lead to effective spin flips, in consequence of which the bound singlet state of the dot spin with the electrons of the leads is formed. This resonance is characterized by SU(2) symmetry. In nanoscopic systems SU(2) Kondo effects have

• are asymmetric and the dip does not enter the Fermi level and the corresponding conductances are finite. For q→∞ the resonance evolves into a Lorentzian peak at EF [89]. It is already partially visible in the transmission for q = 4 that λO = 0 (Figure 2b) and the conductance reaches nearly unitary

• conductance correspond to qeff = 0. Fano–Kondo resonance is also influenced by phonons through the change of Kondo correlations resulting mainly from the renormalization of interdot hopping t’ and transmission variations on the open dot induced by the changes of electron–phonon coupling. Figure 2c shows

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• plasmonic gold (Au) metasurface for sensing volatile organic compounds (VOCs) [49]. This modification enhanced the plasmonic field and local surface plasmonic resonance (LSPR). The influence of the gold nanodisk diameter and the average thickness of the TiO2 fractal on LSPR sensing of VOCs, specifically

Self-assembly of amino acids toward functional biomaterials

• Huan Ren,
• Lifang Wu,
• Lina Tan,
• Yanni Bao,
• Yuchen Ma,
• Yong Jin and
• Qianli Zou

Beilstein J. Nanotechnol. 2021, 12, 1140–1150, doi:10.3762/bjnano.12.85

• coordination of Mn2+, Fmoc-ʟ-L, and Ce6, a yield of 36 wt % can be obtained. After the uptake of FMC NPs by cancer cells, Mn2+ and Ce6 can be released in response to intracellular high levels of glutathione (GSH). Magnetic resonance imaging (MRI) results showed an almost complete elimination of the tumor three

pH-driven enhancement of anti-tubercular drug loading on iron oxide nanoparticles for drug delivery in macrophages

• Karishma Berta Cotta,
• Sarika Mehra and
• Rajdip Bandyopadhyaya

Beilstein J. Nanotechnol. 2021, 12, 1127–1139, doi:10.3762/bjnano.12.84

• biocompatibility and magnetic properties, have found applications in drug delivery, magnetic resonance imaging and treatment of iron deficiencies [3][4][5][6]. The property of hyperthermia has been found to be beneficial in localized drug release, particularly in cancer therapy [7]. In anti-cancer therapy, IONPs

Open-loop amplitude-modulation Kelvin probe force microscopy operated in single-pass PeakForce tapping mode

• Gheorghe Stan and
• Pradeep Namboodiri

Beilstein J. Nanotechnol. 2021, 12, 1115–1126, doi:10.3762/bjnano.12.83

• oscillations is shown in Figure 2. The raw PFT signal (gray curve in Figure 2) is especially noisy right after each detachment of the AFM probe from contact due to the relative compliance of the probe used, with a nominal stiffness of 3.0 N/m and first resonance frequency of 67 kHz. This extra high-frequency

• and small-amplitude ringing was low-pass filtered at 25 kHz, which is a few times larger than the bias frequency, such that the CPD calculations will not be affected by this filter, but below the first resonance frequency to remove the induced ringing. The filtered signal (red curve in Figure 2

• frequency although smaller voltages as low as 2.0 V and higher frequencies up to 30 kHz were found to work as well; no bias frequencies around or above the first resonance frequency of the cantilever were tested. Applied bias, piezo signal, and AFM deflection were simultaneously sampled at 3.0 MSa/s by a

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

• Muhammad Atif Sattar,
• Najwa Al Bouzieh,
• Maamar Benkraouda and
• Noureddine Amrane

Beilstein J. Nanotechnol. 2021, 12, 1101–1114, doi:10.3762/bjnano.12.82

• greater than its bandgap value. The electron energy loss curve achieves its peak value around 13 eV and then begins to abruptly fall until it reaches 13.5 eV. This observed highest peak of L(ω) represents the plasma resonance of the π-SnSe alloy and their correlated frequencies, called plasma frequencies

Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review

• Keshav Nagpal,
• Erwan Rauwel,
• Frédérique Ducroquet and
• Protima Rauwel

Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80

• employed in display applications and lighting systems. Further research on LED that incorporates carbon nanostructures and metal nanoparticles exhibiting surface plasmon resonance has demonstrated a significant improvement in device performance. These devices offer lower turn-on voltages, higher external

• as the emissive layer (EML), the hole transport layers (HTL), the electron transport layers (ETL), the cathode, and the anode [17][18][19][20][21]. Enhancement in LED properties via surface plasmon resonance (SPR) of metal nanoparticles (MNP) such as Au and Ag have also been reported [22][23]. This

• current injections of 100 mA have shown clear enhancements for both types of AuNP in Figure 4a and Figure 4b. Surface plasmon resonance absorbance tends to blueshift with decreasing sizes of the NP. Therefore, the 2 nm AuNP were able to enhance the blue emission from the LED. A similar effect was also

A new method for obtaining model-free viscoelastic material properties from atomic force microscopy experiments using discrete integral transform techniques

• Berkin Uluutku,
• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2021, 12, 1063–1077, doi:10.3762/bjnano.12.79

• . Alternatively, the transfer functions can be fitted to specific viscoelastic models in order to obtain material constants within those models. Illustration of the classical force–distance experiment. The AFM cantilever tip approaches and indents the sample under off-resonance conditions, while the force and

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

• . In contrast, on graphene/Pt(111) the growth of molecular domains is facilitated. Electronically, the width of the highest occupied molecular orbital (HOMO) resonance is reduced by a factor of ten on graphene/Pt(111) compared to bare Pt(111) due to a reduction of the molecule–surface hybridization

• . 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 role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

• Nabojit Das,
• Akash Kumar and
• Raja Gopal Rayavarapu

Beilstein J. Nanotechnol. 2021, 12, 924–938, doi:10.3762/bjnano.12.69

• characteristics, such as interesting plasmonic, optical and catalytic properties, and facile surface modification with tunable size and morphology [1]. Among these properties, the ability of surface plasmon resonance (SPR) at visible to near-infrared (NIR) wavelengths is the most striking characteristic feature

• of gold and silver nanoparticles. Surface plasmon resonance is an inherent property of plasmonic metal nanoparticles that is immensely employed as a tool for theranostics and is highly influenced by the size and shape of the nanoparticle [2]. The property of SPR has also been exploited for nanochips

• surfactant for synthesizing anisotropic nanoparticles with high yield and monodispersity. The surfactant induces anisotropy during the growth of nanoparticles and enables NIR absorption capability due to longitudinal surface plasmon resonance (LSPR) [11]. However, despite the superior plasmonic properties

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu²⁺ ions

• Bahdan V. Ranishenka,
• Andrei Yu. Panarin,
• Irina A. Chelnokova,
• Sergei N. Terekhov,
• Peter Mojzes and
• Vadim V. Shmanai

Beilstein J. Nanotechnol. 2021, 12, 902–912, doi:10.3762/bjnano.12.67

• possible in the case of luminescent dyes. As BHQ1 has a wide band that overlaps the excitation laser frequency, we can speak about surface-enhanced Raman resonance scattering (SERRS) in this case. The unmodified SERS substrate did not show any SERS signal of the oligonucleotide (Figure 8). Based on our

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• conditions for band-excitation piezoresponse force microscopy (PFM) [134]. Band excitation collects a band of frequencies around the contact resonance frequency of the tip–sample system, which is modeled by a simple harmonic oscillator equation. This allows for the determination of several physical

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

• ROS production [149][153]. Miyaji et al. investigated the generation of free radicals from water molecules in the presence of US under aerobic conditions. 5.5-Dimethyl-1-pyroline-N-oxide was used as a trap for HO• free radicals and analyzed using electron spin resonance microscopy after sonolysis [153

• after US triggering under magnetic resonance imaging (MRI) guidance. According to these studies, US irradiation caused distinct NO release. There was a positive association between increasing the power of the US with the rate of NO generation and the cytotoxic effects of NPs on the cancer cells [148

Recent progress in actuation technologies of micro/nanorobots

• Ke Xu and
• Bing Liu

Beilstein J. Nanotechnol. 2021, 12, 756–765, doi:10.3762/bjnano.12.59

• microelectrodes in water and solutions of high ionic strength. When the ultrasonic frequency is tuned to generate a vertical standing wave, the metal rod is suspended in the midpoint plane of a cylindrical cell. A rapid axial movement of 200 μm/s of the metal microprobe at the resonance frequency was observed

• dual-mode fluorescence and magnetic resonance imaging. Using magnetic targeting, the micro/nanorobot broke through complex physiological barriers and entered tumors while carrying a photosensitizer. After that, local high temperature was generated by a near-infrared laser, and observable and accurate

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• [50] also proposed a navigation method for two-dimensional robust magnetic resonance of microrobots using ferromagnetic nanoparticles. Laurent Arcese et al. [51] discussed the control design of an intravascular magnetically guided microrobotic system for performing minimally invasive medical

• materials to propel and rotate microrobots. The force was proportional to the magnetic field gradient and had nothing to do with the induced current, so the resonance frequency could be used. The magnetic material designed by Kim’s team did not rely on the Lorentz force, avoiding the influence of the

Fate and transformation of silver nanoparticles in different biological conditions

• Barbara Pem,
• Marija Ćurlin,
• Darija Domazet Jurašin,
• Valerije Vrček,
• Rinea Barbir,
• Vedran Micek,
• Raluca M. Fratila,
• Jesus M. de la Fuente and
• Ivana Vinković Vrček

Beilstein J. Nanotechnol. 2021, 12, 665–679, doi:10.3762/bjnano.12.53

• implementing light scattering (dynamic and electrophoretic) techniques, spectroscopy (UV–vis, atomic absorption, nuclear magnetic resonance) and transmission electron microscopy. The obtained results demonstrated that AgNPs may transform very quickly during their journey through different biological conditions

• absorption spectroscopy (GF-AAS), nuclear magnetic resonance (NMR) spectroscopy, and transmission electron microscopy (TEM) experiments. Physicochemical characteristics of freshly prepared AgNPs Freshly prepared AgNPs coated with PVP, sodium bis(2-ethylhexyl)sulfosuccinate (AOT), and poly(ʟ-lysine) (PLL

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• /GaAs single quantum well structures were patterned with sets of stripes to emulate a grating structure, using doses of less than 1012 ions/cm2. The result was a periodic spatial modulation of the excitonic resonance of the quantum well perpendicular to the buried quantum well layer. Since the doses

High-yield synthesis of silver nanowires for transparent conducting PET films

• Gul Naz,
• Hafsa Asghar,
• Muhammad Ramzan,
• Muhammad Arshad,
• Rashid Ahmed,
• Muhammad Bilal Tahir,
• Bakhtiar Ul Haq,
• Nadeem Baig and
• Junaid Jalil

Beilstein J. Nanotechnol. 2021, 12, 624–632, doi:10.3762/bjnano.12.51

• electrical conductivity [12]. AgNWs are important as they offer a possibility to overcome light–matter interaction in the visible region. The optical properties of AgNWs are determined by localized surface plasmon resonance (LSPR), which depends on shape, size, and environment of the material [13]. AgNWs

• second peak at 373 nm is attributed to the longitudinal plasmon resonance of AgNWs. It is also noted that no other peak was observed, which shows that the final product was free from contamination of any other nanostructures, such as silver nanoparticles or nanocubes. The SEM results also confirm the

Properties of graphene deposited on GaN nanowires: influence of nanowire roughness, self-induced nanogating and defects

• Jakub Kierdaszuk,
• Piotr Kaźmierczak,
• Justyna Grzonka,
• Aleksandra Krajewska,
• Aleksandra Przewłoka,
• Wawrzyniec Kaszub,
• Zbigniew R. Zytkiewicz,
• Marta Sobanska,
• Maria Kamińska,
• Andrzej Wysmołek and
• Aneta Drabińska

Beilstein J. Nanotechnol. 2021, 12, 566–577, doi:10.3762/bjnano.12.47

• supporting points is not straightforward. Consequently, we cannot calculate the absolute value of strain; however, its qualitative description is still possible. The 2D band has a complex line shape due to the double resonance signal [40][41]. Therefore, the graphene strain could be qualitatively examined by

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• based on a shift of the field emission resonance (FER) induced by Φ variations. The effective potential well of depth Φ at the surface of a metal can accommodate a series of Rydberg states, extending a few angstroms into the vacuum above the metal surface [43]. These image potential states (IPSs

• , independent method to detect the variation in Φ. For this we record the frequency shift, Δf, of the resonance frequency of the cantilever oscillating perpendicular to the surface as a function of the bias voltage (see Figure 3b). At the extrema of the parabolic Δf curves, the electrostatic force is minimised

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• were obtained. Room-temperature AFM Room-temperature nc-AFM measurements were performed with a custom-built non-contact atomic force microscope with Nanonis electronics RC5. PPP-NCL cantilevers (Nanosensor) were used as sensor (typical resonance frequency of f1 = 170 kHz, oscillation amplitude A1 = 2–5

On the stability of microwave-fabricated SERS substrates – chemical and morphological considerations

• Limin Wang,
• Aisha Adebola Womiloju,
• Christiane Höppener,
• Ulrich S. Schubert and
• Stephanie Hoeppener

Beilstein J. Nanotechnol. 2021, 12, 541–551, doi:10.3762/bjnano.12.44

• laser excitation was set to 532 nm which overlaps with the plasmon resonance of the SERS substrates [24]. After an incubation time of eight minutes, the intensity of the characteristic peak of 4-ATP located at 1442 cm−1 reached a maximum intensity which did not further increase after longer incubation