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

• Langevin dynamics method was applied based on the effective Verlet-type algorithm. The Néel magnetic relaxation time was obtained via the Coffey method in an oblique magnetic field, adapted to the local magnetic field on a nanoparticle. Keywords: colloidal system; effective Verlet-type algorithm; magnetic

• relaxation time; nanoparticle coating; numerical simulation; stochastic Langevin dynamics method; superparamagnetic nanoparticles; Introduction One of the most important biomedical applications of colloidal magnetic nanoparticle systems is magnetic hyperthermia applied as an alternative for cancer treatment

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

• the hole or electron to the vibrational quantum with energy hν. The Huang–Rhys factor can be expressed as where εν denotes the relaxation energy of the vibration when charging the molecule [10][41]. Comparing the peak height of the orbital signature (I0) with the first vibronic subband (Iν,1) enables

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

• nanoparticles produce thermal relaxation, leading to a local increase in the temperature. The overall photothermal effect depends on the irradiation intensity and wavelength, nanoparticle concentration, and the nanoparticle photothermal conversion efficiency [33][38]. It also depends on the type of the

• [78]. Similar to the Prussian blue nanoparticles, CuS nanoparticles display a strong absorption in the NIR region, mainly within the 900–1200 nm range, with an efficient thermal relaxation resulting from the d–d energy band transition of the Cu2+ ions. The very low production costs together with a low

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• measured characteristic cool-down time of the heated region is shorter than 20 ms, which is the typical trap relocation feedback time in the experiment. The calculated thermal relaxation time for the substrate, τ = L2/Dthermal, where L = 10 µm and for sapphire is of the order of 10 μs. Sample imaging is

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

• detection. SPIONs have gained a lot of interest in theranostics, which combines diagnostics and treatment by a single intervention, where they show a lot of promise [64][134][135][136][137][138]. Depending on the dimension of the SPIONs, the heating during hyperthermia is determined by Néel relaxation for

• SPIONs smaller than 10 nm, by Néel and Brownian relaxation for SPIONs between 10 and 13 nm (mechanisms in superparamagnetic nanoparticles), and by hysteresis loss for larger SPIONs (mechanism of ferromagnetic nanoparticles) [139]. Hyperthermia potential and efficacy of SPIONs depend on their structure

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

• TCNQ is located right at the onset of the conduction band. This provides relaxation pathways for electrons tunneling into the LUMO, though still significantly less than on the bare metal. Vibronic excitations of TCNQ on MoS2 on Ag(111) Having shown that the resonances at 470 and 640 mV originate both

• vibrational mode k and n its harmonics. The Huang–Rhys factor is determined by the relaxation energy εk of a vibrational mode when charging the molecule as From the DFT calculations of the TCNQ molecule, we determine all vibrational eigenmodes in the negatively charged state and also derive the Huang–Rhys

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• time delay between measurements was 2 s, which was, simultaneously, much smaller than the sensor response time and much higher than the assessed dielectric relaxation time value. In order to transform the resistance signal into a voltage signal, the sample was connected in series to a load resistance

• dielectric relaxation time (τr). As τr = εε0ρ (ρ is the bulk resistivity, ε and ε0 are the permittivity and the electric constant, respectively), it is clear that τr decreases since there is a reduction in the resistivity when the temperature increase and the system reaches steady state in less time. Another

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

• ) were homogeneously distributed throughout the Fe3O4/Gd2O3-DHCA (FGDA) nanocubes. Relaxation time analysis was performed on the images obtained from the 3.0 T scanner. The results demonstrated that r1 and r2 maximum values were 67.57 ± 6.2 and 24.2 ± 1.46 mM−1·s−1, respectively. In vivo T1- and T2

• researchers have been developing strategies to synthesize contrast agents [6][7][8][9]. MRI contrast agents can interact with the hydrogen protons that are present in the surrounding tissue, shortening their relaxation times and leading to signal changes [10]. Generally, contrast agents can be divided into

• two categories depending on the effect they have on MRI. T1 contrast agents shorten longitudinal relaxation times, generating bright signals [11][12][13][14][15], whereas T2 contrast agents shorten transverse relaxation times, generating dark signals [16][17]. Even though T1 contrast agents, such as

Electrochemical nanostructuring of (111) oriented GaAs crystals: from porous structures to nanowires

• Elena I. Monaico,
• Eduard V. Monaico,
• Veaceslav V. Ursaki,
• Shashank Honnali,
• Vitalie Postolache,
• Karin Leistner,
• Kornelius Nielsch and
• Ion M. Tiginyanu

Beilstein J. Nanotechnol. 2020, 11, 966–975, doi:10.3762/bjnano.11.81

• of the Figure 7A. The photocurrent build-up and relaxation for a photodetector produced on a nanowire with a diameter of 400 nm is presented in Figure 7B for an IR illumination density of 800 mW·cm−2. One can see that the current increases by a factor of four in magnitude under illumination with IR

• nanowires is related to their long-relaxation phenomena caused by the strong surface band bending effects [37]. In contrast, much shorter relaxation times are inherent to photodetectors based on interdigitated metal–semiconductor–metal structures with Schottky diodes. However, a very low feature size is

• shutter was used in the relaxation experiments. The signal from the source measure unit was fed to computer via IEEE-488 interface for further data processing. The measurements were performed at 300 K. SEM images in cross section of porous GaAs layers for three different conditions of anodization in 1.75

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

• long duration relaxation of photoconductivity was shown to be characteristic for films prepared by spin coating, while a fast response to irradiation was observed in samples prepared by aerosol spray pyrolysis. Similar to the issues about the influence of the technology on the morphology of films

• to the higher concentration of acceptor levels introduced during spin coating. Long duration relaxation of photoconductivity and persistent photoconductivity was previously observed in highly doped and compensated semiconductors [39], porous semiconductors [48] and solid solutions [40]. The origin of

• fluctuations lead to the formation of potential barriers, which have to be overcome for the recombination of photoexcited carrier to occur during the relaxation processes. On the other hand, the mechanisms for attaining such potential fluctuations were found to be different. In highly doped semiconductors, the

Integrated photonics multi-waveguide devices for optical trapping and Raman spectroscopy: design, fabrication and performance demonstration

• Gyllion B. Loozen,
• Arnica Karuna,
• Mohammad M. R. Fanood,
• Erik Schreuder and
• Jacob Caro

Beilstein J. Nanotechnol. 2020, 11, 829–842, doi:10.3762/bjnano.11.68

• ) and, thus, kx(y) as a function of Pfib. In this procedure it is not needed to take into account the small correction of σΔx(Δy) due to motion blurring [13], in view of the short integration time of the camera compared to the trap relaxation time. To obtain plots of kx(y) as a function of Ptrap, we

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

• nonplanar Pc molecule. As a result, the abovementioned relaxation of a Sn-down Pc molecule leads to an increase in the dipole moment from −0.6 D for gas-phase SnPc to −1.13 D for relaxed SnPc. This effect is mainly due to a change of the position of positively charged H atoms at the periphery of the

• molecular adsorbate and the substrate, as was presented for CuTPP on rutile (110) [33]. The charge state of a CuTPP molecule depends on the particular localization of hydroxy groups under the molecule. For Sn-down Pc molecules, the relaxation brings the macrocycle closer to the surface, which increases long

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

• -dimensionality nanocrystallites, the wave function of the optical phonons no longer remains a continuous plane wave and thus the localization of the wave function leads to a relaxation in the conservation of the wave vector selection rules. The phonons with a nonzero wave vector also take part in the Raman

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

• -stable state is a spin-singlet state. The system non-radiatively relaxes between the excited triplet state |2⟩ and the singlet meta-stable state |3⟩. These non-radiative relaxation processes between the different spin states are known as inter-system crossing (ISC). The decay process between the

• criteria for spin–photon-phonon entanglement distribution are high electron spin coherence time T2 (approaching T2 spin-lattice relaxation time) and strain and electrical control of the spin transition and optical transition resonances. The key requirements can be restrictive depending on the applications

• photons exciting electrons to a higher energy level in an atom. This photo-excitation is then followed by various relaxation processes. During these relaxation processes, other photons can be re-irradiated. One interesting parameter is the zero-phonon line (ZPL), which is the difference between the lowest

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• connected to semi-infinite AGNR contacts at both sides. The energy band edge diagram of the proposed RTD along with the quantized energy level of the well are shown in Figure 1b. Due to small lattice mismatch between graphene and hBN the edge bond relaxation correction for carbon atoms at the interface of C

Observation of unexpected uniaxial magnetic anisotropy in La_2/3Sr_1/3MnO₃ films by a BaTiO₃ overlayer in an artificial multiferroic bilayer

• John E. Ordóñez,
• Lorena Marín,
• Luis A. Rodríguez,
• Pedro A. Algarabel,
• José A. Pardo,
• Roger Guzmán,
• Luis Morellón,
• César Magén,
• Etienne Snoeck,
• María E. Gómez and
• Manuel R. Ibarra

Beilstein J. Nanotechnol. 2020, 11, 651–661, doi:10.3762/bjnano.11.51

• layer are promoted by the large mismatch between the lattice parameters of the BTO and the strained LSMO film (≈2.4%). They correspond to misfit dislocations created parallel and perpendicular to the interface and favor the relaxation of the BTO atomic layers placed far from the BTO/LSMO interface. For

• relaxation of the BTO layer, hence horizontal misfit dislocations are not formed. Similar profiles were extracted from the εzz strain maps. Compared to the εxx, the εzz profiles present noisier behavior inherent to the GPA method [57], with an extended and strong variation around each interface that does not

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• signal generation magnitude compared to the Vegard expansion or their time scales are much shorter than the relaxation times for ESM experiments (Maxwell relaxation times) [30][32]. Electrochemical side reactions may create surface features, which, however, are detectable by subsequent scans of the same

• signal can be found in Supporting Information File 1. Since the variation of the ESM signal is governed by migration and diffusion processes, it can be used to fit relaxation functions and extract the characteristic time constant τ. Diffusion processes are often fitted using an exponential decay function

• iron dissolution the lower ESM signal is a direct consequence. It is noted that this is probable, as Fe-dissolution has been reported as the prominent degradation mechanism of LFP [9][72][73]. The dynamics of the relaxation process after the dc-voltage pulse are further analysed in Figure 7 and Figure

Luminescent gold nanoclusters for bioimaging applications

• Nonappa

Beilstein J. Nanotechnol. 2020, 11, 533–546, doi:10.3762/bjnano.11.42

• /ethanol (90/10 v/v) mixture compared to that of in pure ethanol solution. In solution, the dynamic intramolecular rotation serves as a route for nonradiative relaxation process. Upon aggregation, the intramolecular rotations are restricted, which blocks the non-radiative pathways and opens the radiative

Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

• Nicole Fillafer,
• Tobias Seewald,
• Lukas Schmidt-Mende and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

• combination of azobenzene molecules with conducting or semiconducting materials is of high interest. In connection with semiconductors the occurrence of interesting phenomena has been proposed. The symmetry-allowed π→π* transition and the subsequent structural relaxation can be affected by the electronic

• ligands attached to semiconductors can change conformation under irradiation with light is still a question that is being discussed. Rego et al. simulated a very fast charge transfer from azobenzene to the conduction band of TiO2, followed by a strong vibronic relaxation that excites the N–N stretching

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

• augmented wave potential (PAW) [36]. In the geometry relaxation calculations, all forces acting on the atoms were converged to within 0.02 eV/Å. The bulk structure of MoS2 used in this study was chosen from the “Materials Project” database [37]. The bulk material contains two layers of MoS2. The geometry

• not influenced by the adsorption site. It is of note that the atoms remain at the site where they were originally adsorbed throughout relaxation. This is also apparent from the computed addition energies. The addition of an atom to Cu2 to form a 3D Cu3 cluster is very favourable, with computed

• structures, the atoms remain at their original adsorption site throughout the relaxation for all Cu4 structures. For the linear Cu4 configuration the binding energy at site 1 is only 0.06 eV per Cu more negative than at site 3 and 0.07 eV less negative than at site 2, indicating little difference in

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• electron–hole annihilation at the D–A interfaces. Here, we do not discuss the losses by exciton relaxation or by pairwise recombination of the CT state. The free carriers can also be trapped in tail states [25] before recombining with free unpaired counter charges. This slower recombination process is

Facile biogenic fabrication of hydroxyapatite nanorods using cuttlefish bone and their bactericidal and biocompatibility study

• Satheeshkumar Balu,
• Manisha Vidyavathy Sundaradoss,
• Swetha Andra and
• Jaison Jeevanandam

Beilstein J. Nanotechnol. 2020, 11, 285–295, doi:10.3762/bjnano.11.21

• ]. Thus, it is evident that the reaction at basic pH conditions and a temperature of 80 °C supports the relaxation of aragonite calcium carbonate bonds to form calcite structure in 3 h [24]. It can be noted from the diffraction peaks that the formation of Hap crystal growth was initiated at 6 h of

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

• potential. This electron transfer determines a finite relaxation time τσ, that can be calculated using second-order perturbation theory [12][13]. It can be intuitively introduced by substituting δ in the self-energies Σiσ(ω) with [31][34]. By considering a small value for e.g., = δ ≈ 10−7 [31], the

The effect of heat treatment on the morphology and mobility of Au nanoparticles

• Sven Oras,
• Sergei Vlassov,
• Simon Vigonski,
• Boris Polyakov,
• Mikk Antsov,
• Vahur Zadin,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2020, 11, 61–67, doi:10.3762/bjnano.11.6

• twinned NPs and the tendency of such particles to seek mechanisms of stress relaxation [25]. The rearrangement of surface atoms into more rounded outer geometries can be a way of energy minimization while preserving the five-fold twinned inner structure of the NP, as shown in Figure 3 for a Au NP heated

Fully amino acid-based hydrogel as potential scaffold for cell culturing and drug delivery

• Dávid Juriga,
• Evelin Sipos,
• Orsolya Hegedűs,
• Gábor Varga,
• Miklós Zrínyi,
• Krisztina S. Nagy and
• Angéla Jedlovszky-Hajdú

Beilstein J. Nanotechnol. 2019, 10, 2579–2593, doi:10.3762/bjnano.10.249

• induced by the cleavage of the disulfide bonds. The change of the ionic strength is a faster process, therefore, the relaxation time determined for the 0CYS-LYS hydrogel is smaller than that of the 20CYS-LYS hydrogel. Dependence of the swelling degree of the PASP-20CYS-LYS gels on the amount of DTT in the