Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• because of a change of the boundary conditions. The luminescence quenching of QDs in the active LC matrix with an increase in the electric field strength occurs when the position of the LC director with respect to the electric field vector changes. The parallel component of the dielectric constant of the

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• altering the salt concentration of the suspension solution affected the velocity of particles due to the change of dielectric constant and viscosity of the solution. These findings suggest that this technique is suitable for studying particle surface changes and perhaps can be used to dynamically study

• microscope is efficient in characterization of polymer-coated nanoparticles. However, due to the fact that the nanoparticle scattering intensity depends on the dielectric constant of the material, multicomponent particle coatings, especially those on metallic or metal oxide materials such as those studied

• studies of reaction kinetics at the particle surface that result in changes in particle size, dielectric constant, or surface chemistry, which is of particular interest in protein adsorption to nanoparticles for biomedical applications. Results and Discussion Size, morphology, and elemental analysis of

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• (EFM) phase with high resolution as a function of the electrical direct current bias applied either to the probe or sample. Based on the dielectric constant difference of graphene oxide (GO) sheets (reduced using various methods), EFS can be used to characterize the degree of reduction of uniformly

• or valley EFM phases) and the EFM phase contrast at a certain tip bias less than the peak value can all indicate the degree of reduction of rGO samples, which is positively correlated with the dielectric constant. In addition, we gave the ranking of degree for reduction on thermally or chemically

• graphene domains and optimize EFM imaging [27]. The EFS is a method monitoring the EFM phases with high resolution as a function of the electrical DC bias applied either to the probe or sample. Based on the dielectric constant difference of rGO sheets reduced using various methods, EFS can characterize the

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• region of the image is proportional to the dielectric constant of the material underneath the EFM tip, surface potential differences and to any accumulated charges/permanent polarization at the surface [34]. Equation 2 was used to fit all experimental data in Figure 4c–e (blue or brown solid lines in

• these plots) and Table 1 shows the respective fitting parameters. Considering, initially, parameter α in Table 1, which is related to the geometric capacitance and dielectric constant, there is no significant variation, as expected, since the geometric capacitance should remain the same. The minor

• variation of α for both functionalized graphene (Gf) and RA upon illumination may reflect slight changes on the hybrid dielectric constant upon charge transfer (doping). Such charge transfer, including photo-generated charges, may also account for the observed variation of parameter γ in Table 1, which is

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• both of the wetting and dielectric properties of the sample. Based on this principle, a quantitative analysis on the dielectric constant of macroscopic film has been realized by measuring the surface–water contact angle and adhesion force between the dielectric layer and a biased AFM tip [38]. Recently

• , Fadh, will increase due to sample polarization (Figure 1b), which is positively correlated to its dielectric constant. Therefore, adhesion force mapping under a biased AFM tip can be expected to characterize the local dielectric property distribution. An example of adhesion force mapping with a biased

• after being chemically reduced by removing some oxygen-containing groups and has a similar thickness but a larger dielectric constant than GO [21][45]. Figure 3a shows a representative height image of a mixture of GO and CRGO on a mica substrate under the tip biased at 0 V under ambient conditions (room

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• dielectric constant of the colloid consisting of liquid crystal and ferroelectric particles can be represented in the form Here, f is the volume fraction of ferroelectric particles, εLC(E) and εFP(E) are the permittivity values of LC and ferroelectric particles both depending on the electric field strength E

• field, that leads to an increase in the dielectric constant of the colloid (the first section of the curve in Figure 3). If the applied field exceeds the threshold value, εLC(E) significantly increases, which is reflected in the dielectric permittivity of the colloid (third segment). Figure 3 shows that

• the dielectric constant of the colloid after the planar–homeotropic transition is much lower than that of the pure LC. This is due to the imperfection of the final homeotropic state (Figure 2,c). The decrease in the permittivity in the voltage range from 6 to 16 V (the second part of the curve in

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• allow the enhanced absorption of photon energy from the visible light spectrum. Larger metallic nanoparticles (>5 nm) produce a robust surface plasmon emission in the visible spectrum [10]. The intensity of the plasmon band is highly dependent on the morphology, surrounding medium dielectric constant

Facile synthesis of ZnFe₂O₄ photocatalysts for decolourization of organic dyes under solar irradiation

• Arjun Behera,
• Debasmita Kandi,
• Sanjit Manohar Majhi,
• Satyabadi Martha and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 436–446, doi:10.3762/bjnano.9.42

• the band edge of the prepared materials. The Mott–Schottky graphs were plotted according to Equation 2: where C, Vfb, k, T, e, ND, ε, ε0 and A are capacitance of the sample, flat-band potential, Boltzmann constant, absolute temperature, electron charge, donor density, semiconductor dielectric constant

• , dielectric constant in vacuum and area, respectively. C−2 was plotted as a function of the applied potential, Vapp. The extrapolation of the graph leads to the intersection point at the Y-axis, which gives the flat-band potential of the sample [33]. Figure 8 shows the Mott–Schottky plot of ZFO-500. The

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• dielectric constant of the QDs (εQD) and the volumetric fraction of the quantum dots (cv). The intraction free energy between nematic molecules and a quantum dot can be calculated from the Rapini formula [21]. Considering an elliptical quantum dot with one of the axes just a little bit longer than the others

The nanofluidic confinement apparatus: studying confinement-dependent nanoparticle behavior and diffusion

• Stefan Fringes,
• Felix Holzner and
• Armin W. Knoll

Beilstein J. Nanotechnol. 2018, 9, 301–310, doi:10.3762/bjnano.9.30

• interaction energy U(h) of a charged spherical particle at a distance h to a charged plane is given by [23][36]: where κ−1 is the Debye length, ε is the dielectric constant of the medium, ε0 is the vacuum permittivity, a is the radius, and ψP,eff and ψS,eff are the effective surface potentials of plane and

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

Al₂O₃/TiO₂ inverse opals from electrosprayed self-assembled templates

• Arnau Coll,
• Sandra Bermejo,
• David Hernández and
• Luís Castañer

Beilstein J. Nanotechnol. 2018, 9, 216–223, doi:10.3762/bjnano.9.23

• opals is challenging, requiring large size, three-dimensional ordered layers of high dielectric constant ratio. In this article, alumina/TiO2–air inverse opals with a 98.2% reflectivity peak at 798 nm having an area of 2 cm2 and a thickness of 17 µm are achieved using a sacrificial self-assembled

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes

• Doina Manaila Maximean,
• Viorel Cîrcu and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 164–174, doi:10.3762/bjnano.9.19

• studies while the corresponding phase transition enthalpies were obtained by DSC. The ILC was doped with CNT in concentration of 0.05% w/w and 0.5% w/w. The dielectric spectra were recorded in the frequency range from 10−1 to 107 Hz. The dependence of the dielectric constant and electric energy loss on

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

• Doina Manaila Maximean,
• Octavian Danila,
• Pedro L. Almeida and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 155–163, doi:10.3762/bjnano.9.18

• techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the

• dielectric constant, and the imaginary part, iε″(ω), is the dielectric loss [37]. Figure 4 shows dielectric constant and dielectric loss as functions of the temperature at two constant representative frequencies, 1 Hz and 10 Hz, for (a) the cell with CA fibers before filling in the LC, and (b) for the same

• fitting parameters of the Vogel–Fulcher–Tammann law (see below in Figure 6 and Table 1). Figure 5 presents dielectric constant and dielectric loss as functions of the frequency for the CA cell (a) before and (b) after filling in the LC, at three constant temperatures. For the CA sample without LC measured

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• representative characteristic elastic constant in the single elastic constant approximation, is the external electric field, ε0 is the permittivity of free space, and Δε is the dielectric constant anisotropy. We model conditions at the LC confining boundaries either by [15][16]: or where w is the surface

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• ]: where сi – ion density, q – elementary charge, D – average diffusion coefficient, ε0 – dielectric constant, d – thickness of the cell gap, kB – Boltzmann factor, T – temperature, f – frequency, and ε∞ – high-frequency dielectric permittivity. We have evaluated the ion density and the average diffusion

Enhanced photoelectrochemical water splitting performance using morphology-controlled BiVO₄ with W doping

• Xin Zhao and
• Zhong Chen

Beilstein J. Nanotechnol. 2017, 8, 2640–2647, doi:10.3762/bjnano.8.264

• [22]: where e0 is the electron charge (1.60·10−19 C), ε is the dielectric constant of BiVO4 (68) [23][24], ε0 is the electrical permittivity of vacuum (8.85·10−12 F·m−1), A is the electrode area, Nd is the donor density, V is the potential applied at the electrode, and C is the surface capacitance

Refractive index sensing and surface-enhanced Raman spectroscopy using silver–gold layered bimetallic plasmonic crystals

• Somi Kang,
• Sean E. Lehman,
• Matthew V. Schulmerich,
• An-Phong Le,
• Tae-woo Lee,
• Stephen K. Gray,
• Rohit Bhargava and
• Ralph G. Nuzzo

Beilstein J. Nanotechnol. 2017, 8, 2492–2503, doi:10.3762/bjnano.8.249

• effect which limits the degree of conformal coverage realized in the sputter coating metallization step. In the calculation, we used a Drude plus two-pole Lorentzian model to obtain the dielectric constant of the metal as a function of wavelength [48][61]. Figure 2 presents the experimentally measured

Synthesis of metal-fluoride nanoparticles supported on thermally reduced graphite oxide

• Alexa Schmitz,
• Kai Schütte,
• Vesko Ilievski,
• Juri Barthel,
• Laura Burk,
• Rolf Mülhaupt,
• Junpei Yue,
• Bernd Smarsly and
• Christoph Janiak

Beilstein J. Nanotechnol. 2017, 8, 2474–2483, doi:10.3762/bjnano.8.247

• important technical applications [15][16][17][18][19][20][21][22]. They can be used as composite materials [23][24], in chemical sensors [25], electrodes for fuel cells [26][27][28], for catalysis [29][30][31][32] or for hydrogen storage [33]. Because of their high ionic charge, polarity and dielectric

• constant, ILs are an ideal media for microwave reactions and for the stabilization of M-NPs [34][35][36][37]. Soft wet-chemical synthesis in organic solvents from metal-organic complexes is an essential method to obtain metal or metal alloy nanoparticles [38][39][40][41][42][43][44][45][46][47][48][49][50

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• capacitance (C) can be estimated considering a metallic cylinder-plane system from [19]: where L is the length of the FET channel, ε0 the vacuum permittivity, εr = 3.9 the relative dielectric constant of the SiO2 insulator layer, h = 300 nm the thickness of the SiO2 layer, and d the nanowire diameter. From

Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

• Pavel L. Padnya,
• Irina A. Khripunova,
• Olga A. Mostovaya,
• Timur A. Mukhametzyanov,
• Vladimir G. Evtugyn,
• Vyacheslav V. Vorobev,
• Yuri N. Osin and
• Ivan I. Stoikov

Beilstein J. Nanotechnol. 2017, 8, 1825–1835, doi:10.3762/bjnano.8.184

• in methanol (Figure 4, Supporting Information File 1, Figure S29). It turned out that the emission maxima are close for all compounds in methanol, which indicates the absence of excimer formation. Perhaps this is due to the fact that in water, as a more polar solvent (dielectric constant 78.36

The effect of the electrical double layer on hydrodynamic lubrication: a non-monotonic trend with increasing zeta potential

• Dalei Jing,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2017, 8, 1515–1522, doi:10.3762/bjnano.8.152

• = [2n0c2e2/(εε0kBT)]1/2 (n0 is the original bulk ion concentration of the lubricant, c is the chemical valence of free ions in the lubricant, e is the elementary charge, ε is the lubricant’s relative permittivity, and ε0 is vacuum’s absolute dielectric constant) is the reciprocal of the Debye length, z is

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• of εr = 4 is assumed for the dielectric constant of h-BN, as proposed by Kim et al. [19] for 2–5 nm thin h-BN films. Using the following formula, the resulting energy shift can be estimated: Approximating the ion as a point charge yields an estimate for the energy shift of about 0.64 eV, compared to

• of the molecular position d and the dielectric constant of a single sheet of h-BN. Similar STS measurements of pentacene were carried out on KCl/Au(111), KCl/Cu(111) and KCl/(Cu110). The resulting STS data are depicted in Figure 7. The HOMO–LUMO gap can be used as a measure of the efficiency of an

Micro- and nano-surface structures based on vapor-deposited polymers

• Hsien-Yeh Chen

Beilstein J. Nanotechnol. 2017, 8, 1366–1374, doi:10.3762/bjnano.8.138

• , dielectric constant, temperature, and morphology and various chemical compositions [58][59][60][61][62][63][64][65]. Because of the challenges in fabrication processes, gradients are often generated with solution-based technology. Limitations remain for the ongoing technologies, for example, the lack long

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

• Carlos Angulo Barrios and
• Víctor Canalejas-Tejero

Beilstein J. Nanotechnol. 2017, 8, 1231–1237, doi:10.3762/bjnano.8.124

• (thickness tAl) and varying on the sidewalls from a value of 0.5 × (tAl − tAlO) at the upper vertical surfaces to tAl at the bottom (on the Al substrate). The top cladding (superstrate) is considered to be air. The dielectric constant of Al was modelled by the well-known Drude–Lorentz equation. The