Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

• Martina Banchelli,
• Bruno Tiribilli,
• Roberto Pini,
• Luigi Dei,
• Paolo Matteini and
• Gabriella Caminati

Beilstein J. Nanotechnol. 2016, 7, 9–21, doi:10.3762/bjnano.7.2

• substrates were simultaneously coated by the same AgNC layer. Quartz crystal microbalance measurements. QCM experiments with impedance monitoring were performed on a QCM-Z500 (KSV Instruments Ltd) equipped with a thermoelectric (TE) module (Oven Instruments). The resonant frequency shift and the change in

A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials

• Daniela Lehr,
• Markus R. Wagner,
• Johanna Flock,
• Julian S. Reparaz,
• Clivia M. Sotomayor Torres,
• Alexander Klaiber,
• Thomas Dekorsy and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2015, 6, 2161–2172, doi:10.3762/bjnano.6.222

• molecular scale (Hal = I, Br, Cl). We report about the synthesis of the precursors, their transformation into halogene-containing ZnO materials, and finally structural, optical and electronic properties are investigated using a combination of techniques including FT-Raman, low-T photoluminescence, impedance

• longitudinal optical phonon–plasmon coupling and describes the interaction of collective oscillating free carriers (plasmons) with LO phonons [80]. Consequently, the concentration of free carriers increases with Cl doping. The dielectric properties of thin ZnO1−xClx pellets were investigated with impedance

• spectroscopy. In the Nyquist plot in Figure 6 the imaginary part of the impedance is plotted as a function of the real part. For materials having resistive and capacitive components a series of two semicircles usually occurs in the Nyquist plot. The semicircle in the high frequency region is assigned to grain

Electrochemical behavior of polypyrrol/AuNP composites deposited by different electrochemical methods: sensing properties towards catechol

• Celia García-Hernández,
• Cristina García-Cabezón,
• Cristina Medina-Plaza,
• Fernando Martín-Pedrosa,
• Yolanda Blanco,
• José Antonio de Saja and
• María Luz Rodríguez-Méndez

Beilstein J. Nanotechnol. 2015, 6, 2052–2061, doi:10.3762/bjnano.6.209

• incorporated in the Ppy films was higher when electropolymerization was carried out by chronopotentiometry (CP). Besides, cogeneration method allowed for the incorporation of a higher number of AuNPs than trapping. Impedance experiments demonstrated that the insertion of AuNPs increased the conductivity. As an

• incorporated in the Ppy films was higher when using CP than that when using CA. In turn, using cogeneration, the amount of nanoparticles incorporated was higher than using trapping. Electrochemical impedance spectroscopy Electrochemical impedance spectroscopy (EIS) can provide information about the

• conductivity changes resulting from the insertion of AuNPs in the Ppy films. The complex impedance can be plotted as the real (Zreal) vs imaginary (Zimaginary) components (Nyquist plot), which are related to the resistance and capacitance of the cell, respectively. At high frequencies (left part of the diagram

Nitrogen-doped graphene films from chemical vapor deposition of pyridine: influence of process parameters on the electrical and optical properties

• Andrea Capasso,
• Theodoros Dikonimos,
• Francesca Sarto,
• Alessio Tamburrano,
• Giovanni De Bellis,
• Maria Sabrina Sarto,
• Giuliana Faggio,
• Angela Malara,
• Giacomo Messina and
• Nicola Lisi

Beilstein J. Nanotechnol. 2015, 6, 2028–2038, doi:10.3762/bjnano.6.206

• temperature, while it is not influenced by the hydrogen flow. The films grown at 930 °C have all an average transmittance of 94% at 550 nm, those grown at 1000 °C have 90%, while the 1070 °C samples have 83%. The optical conductivity was calculated as T = (1 + Z0/2 σOp·t)−2, where Z0 is the impedance of free

Optimized design of a nanostructured SPCE-based multipurpose biosensing platform formed by ferrocene-tethered electrochemically-deposited cauliflower-shaped gold nanoparticles

• Wicem Argoubi,
• Maroua Saadaoui,
• Sami Ben Aoun and
• Noureddine Raouafi

Beilstein J. Nanotechnol. 2015, 6, 1840–1852, doi:10.3762/bjnano.6.187

• and concentration of the ferrocene derivatives have been studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Selectivity and specificity tests have been also performed in the presence of potentially interfering substances to

• competitive proteins using a panel of electrochemical techniques such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Application of the two platforms for the detection of hIgG and H2O2 respectively in human serum and in honey are presented

• obtained nanostructures which should be carefully optimized before stepping further. Electrochemical properties of the nanostructured surface To further investigate the properties of the modified carbon surface, it was characterized using cyclic voltammetry, chronocoulometry and electrochemical impedance

Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte

• Sanghoon Ji,
• Waqas Hassan Tanveer,
• Wonjong Yu,
• Sungmin Kang,
• Gu Young Cho,
• Sung Han Kim,
• Jihwan An and
• Suk Won Cha

Beilstein J. Nanotechnol. 2015, 6, 1805–1810, doi:10.3762/bjnano.6.184

• via impedance spectroscopy To investigate the effects of BEC thickness on the individual resistances, electrochemical impedance spectroscopy (EIS) data were obtained for the Cell-A and Cell-B. Before comparing the EIS data for two kinds of cells, the EIS curves obtained under different direct current

• , respectively. The Cell-A, on the other hand, shows the EIS behavior with a diagonal form at a lower frequency region below 20 Hz, which is not observed in the impedance spectra of Cell-B. This diagonal component is considered to the effect of Waburg element signifying a lack of active fuel supply [13]. This

• (left side) and 320 (right side) nm-thick BECs; (B) transmission electron microscopic image for 80 nm pore AAO supported 320 nm-thick BEC. Tafel plots, measured at 500 °C, for the Cell-A and Cell-B. Electrochemical impedance spectroscopy analysis results, measured at 500 °C, at bias voltage of 0.1 V for

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• electromagnetic noise by using absorbing materials. Earlier, carbon black, metal flakes, iron balls and recently carbon nanotubes with magnetic particles were used as absorbent. However, there are some limitations such as a fixed absorption range, difficulties during synthesis, impedance matching problems [3

• energy. Reflection loss calculation has been carried out by using the input impedance from the following relations in accordance with theory of absorbing wall [41]: where Z is the normalized input impedance, ε* is complex permittivity and µ* is the complex permeability, λ is the wavelength and tis the

Attenuation, dispersion and nonlinearity effects in graphene-based waveguides

• Almir Wirth Lima Jr.,
• João Cesar Moura Mota and
• Antonio Sergio Bezerra Sombra

Beilstein J. Nanotechnol. 2015, 6, 1221–1228, doi:10.3762/bjnano.6.125

• nanoribbons is given by [17]: where εr is the relative permitivity in which the graphene nanoribbon is embedded. The dispersion relation for graphene nanoribbons for TM modes propagating along a graphene/dielectric interface is also given by [18]: where η0 = 377 Ω is the air impedance and k0 = 2π/λ0

Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

• Agylych Atdayev,
• Alexander L. Danilyuk and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2015, 6, 1056–1064, doi:10.3762/bjnano.6.106

• matrix. The interface between the NPs and the CNT matrix was also considered and characterized by the wave impedance, Zi. The calculated R and T coefficients adequately describe the experimental data for the X and Ka bands [8]. Here, we modify this approach [8] by specifying the expressions for the

• : where ε1 and ε2 are the relative permittivities of the carbon matrix and the NP, respectively, ε0 is permittivity of vacuum, and σ is the specific conductivity of CNT-based nanocomposite. The reflection coefficient is determined as where , and Z0 = 377 Ω is the characteristic impedance of the plane wave

• in vacuum. The transmission coefficient, which determines the efficiency of shielding, consists of the absorption, reflection, and multi-reflection processes, where d is the nanocomposite thickness, and is the propagation coefficient. The impedance of the nanocomposite depends on the contribution of

From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

• Philipp Adelhelm,
• Pascal Hartmann,
• Conrad L. Bender,
• Martin Busche,
• Christine Eufinger and
• Juergen Janek

Beilstein J. Nanotechnol. 2015, 6, 1016–1055, doi:10.3762/bjnano.6.105

• chosen for several reasons: Counteracting the sluggish cathode reactions, lowering the cell impedance, eliminating dendrites and minimizing interference with water and carbon dioxide. On the other hand, the high reactivity towards the electrolyte was an issue. The cell discharged at 1.75 V (100 µA) and

Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature

• Hamdi Baccar,
• Atef Thamri,
• Pierrick Clément,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2015, 6, 919–927, doi:10.3762/bjnano.6.95

• used as reported in [40]. Gas sensing measurements The electrical characterisation under gas or vapour environment was performed employing an HP 4192A impedance analyzer [17]. Since all devices showed a resistive behavior at frequencies below 100 kHz, the resistance of the metal-decorated carbon

Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

• Jana Vlachová,
• Rebekka König and
• Diethelm Johannsmann

Beilstein J. Nanotechnol. 2015, 6, 845–856, doi:10.3762/bjnano.6.87

• related to the dissipation factor, D, by D = Γ/(2f). fF is the fundamental frequency, which is often 5 MHz. Zq = 8.8 × 106 kg∙m−2s−1 is the shear wave impedance of AT-cut quartz. is the area-averaged complex amplitude of the tangential stress at the resonator surface, and u0 is the amplitude of

• oscillation. The ratio of stress and velocity (where the latter is equal to iωu0) is the complex load impedance, ZL. In the second step in Equation 1, the stress was converted to force by area. The force, in turn, was expressed as tangential stiffness times amplitude (that is, as κu0). n is the overtone order

• Equation 3 and the principle of operation of lock-in amplifiers. Δf and ΔΓ are proportional to the in-phase and the out-of-phase components of the force. Underlying both Equation 1 and Equation 3 is the small load approximation, which states that the load impedance (often called ZL, the ratio of σ0 and

Entropy effects in the collective dynamic behavior of alkyl monolayers tethered to Si(111)

• Christian Godet

Beilstein J. Nanotechnol. 2015, 6, 583–594, doi:10.3762/bjnano.6.60

• Technologies). The sample holder was inserted in a two terminal active cell with the impedance converter mounted directly above the sample. The junction was placed into a cryostat under dry nitrogen flow to avoid extensive water condensation and to minimize surface oxidation during electrical measurements [39

Electrical response of liquid crystal cells doped with multi-walled carbon nanotubes

• Amanda García-García,
• Ricardo Vergaz,
• José F. Algorri,
• Xabier Quintana and
• José M. Otón

Beilstein J. Nanotechnol. 2015, 6, 396–403, doi:10.3762/bjnano.6.39

• characteristic impedance has been studied at different frequencies and excitation voltages. The results demonstrate alterations in the anisotropic conductivity of the samples with the applied electric field, which can be followed by monitoring the impedance evolution with the excitation voltage. Results are

• consistent with a possible electric contact between the coated substrates of the LC cell caused by the reorientation of the nanotubes. The reversibility of the doped system upon removal of the electric field is quite low. Keywords: carbon nanotubes; Cole–Cole diagrams; impedance; liquid crystal; PEDOT:PSS

• LC cells under different conditions seems to be missing. This could be achieved by studying the impedance evolution of the doped cells with voltage and frequency. Indeed, the electrical response may be fairly complex since dielectric and anisotropic conductive elements are present in the system. The

Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

• Lisa Landgraf,
• Ines Müller,
• Peter Ernst,
• Miriam Schäfer,
• Christina Rosman,
• Isabel Schick,
• Oskar Köhler,
• Hartmut Oehring,
• Vladimir V. Breus,
• Thomas Basché,
• Carsten Sönnichsen,
• Wolfgang Tremel and
• Ingrid Hilger

Beilstein J. Nanotechnol. 2015, 6, 300–312, doi:10.3762/bjnano.6.28

• monolayers around the CdSe core of QDs showed that the lowest impact on cell metabolism (cellular dehydrogenase activities) was present when QDs were coated with two monolayers (Figure S1, Supporting Information File 1). Impedance measurements (electric cell–substrate impedance sensing, ECIS) revealed a

• nanoparticles and nearly absent for the D-penicillamine (DPA)-coated QDs. These effects most certainly depend upon the positive charge of CyA, which resulted in an electrostatic attraction to the negatively charged cell membranes. Beyond impedance measurements, the MTS assay with endothelial cells (SVEC4-10

• , Germany) after a 4 h incubation period at 37 °C. The production of light was measured with a luminescence plate reader (BMG LABATECH GmbH, Germany). Relative cellular dehydrogenase and ATP levels were expressed as relative values to the untreated control. Measuring cell viability through impedance

The effect of surface charge on nonspecific uptake and cytotoxicity of CdSe/ZnS core/shell quantum dots

• Vladimir V. Breus,
• Anna Pietuch,
• Marco Tarantola,
• Thomas Basché and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 281–292, doi:10.3762/bjnano.6.26

• -Planck-Institute for Dynamics and Self-Organization (MPIDS), Laboratory for Fluid Dynamics, Pattern Formation and Biocomplexity, Am Fassberg 17, 37077 Goettingen, Germany 10.3762/bjnano.6.26 Abstract In this work, cytotoxicity and cellular impedance response was compared for CdSe/ZnS core/shell quantum

• -particle tracking), was shown to compromise the integrity of the cytoskeletal and plasma membrane dynamics, as evidenced by electric cell–substrate impedance sensing. Keywords: biocompatibility; CdSe/ZnS; cytotoxicity; ECIS; quantum dots; single-particle tracking; Introduction Quantum dots (QDs) are

• membrane permeability assays. We demonstrate that these methods, however, can overlook other more subtle impacts on cell viability and metabolism caused by binding of QDs to cellular compartments, without release of Cd2+ ions. In the present study, we use a noninvasive and label-free impedance setup to

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• enzymes. More advanced techniques, like electric cell-substrate impedance sensing (ECIS) or quartz crystal microbalance measurements monitor the vertical cell motility, i.e., dynamic changes of the cell-substrate distance, as a reporter for cell viability [1][10][11][12][13][14][15]. Mechanical properties

• epithelial cells was shown to be corrupted by gold-nanoparticle exposure in these previous publications, we decided to monitor viscoelastic changes and metabolically driven shape fluctuations in real-time by means of acoustic and impedance-based sensors like QCM and ECIS; the latter furthermore enabled us to

Kelvin probe force microscopy in liquid using electrochemical force microscopy

• Liam Collins,
• Stephen Jesse,
• Jason I. Kilpatrick,
• Alexander Tselev,
• M. Baris Okatan,
• Sergei V. Kalinin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2015, 6, 201–214, doi:10.3762/bjnano.6.19

• effects, which cannot be obtained using linear bias sweeps (e.g., CV measurements), ultimately requiring either pulsed electrochemical or impedance measurements [57]. To achieve this goal, a multidimensional spectroscopic strategy was implemented, which is capable of probing both the bias- and time

• electronic charge and z is the ion valence. At low biases (Vdc < kT/e ≈ 25 mV) and in the absence of Faradaic reactions, this RC time is the relevant timescale of the transient response, e.g., in high-frequency impedance spectroscopy experiments or induced charge electrokinetics, where high-frequency

Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating

• Christina Rosman,
• Sebastien Pierrat,
• Marco Tarantola,
• David Schneider,
• Eva Sunnick,
• Andreas Janshoff and
• Carsten Sönnichsen

Beilstein J. Nanotechnol. 2014, 5, 2479–2488, doi:10.3762/bjnano.5.257

• polymer induced a reduction by 30% and 40%, respectively, which is absent for the carboxy-terminated polymer. Furthermore, interface-sensitive impedance spectroscopy (electric cell–substrate impedance sensing, ECIS) was employed in order to investigate the micromotility of cells added to substrates

• nanorods, which were applied to the basolateral side of the cells, has a recognizable influence on the growth behavior and thus the coating should be carefully selected for biomedical applications of nanoparticles. Keywords: basolateral application; cytotoxicity; electric cell–substrate impedance sensing

• properties of the coating agent and its reactive group. The impact on surfactant-induced cell behavior was investigated in more detail by interface-sensitive impedance spectroscopy (electric cell–substrate impedance sensing, ECIS). Studies on the uptake and influence on metabolic activity with respect to

High-frequency multimodal atomic force microscopy

• Adrian P. Nievergelt,
• Jonathan D. Adams,
• Pascal D. Odermatt and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2014, 5, 2459–2467, doi:10.3762/bjnano.5.255

• mirror based readout has two major advantages over a conventional, purely operational amplifier based readout. The large increase in speed is achieved by the very low input impedance of current mirrors, thus countering the negative impact of diode parasitics on the total bandwidth. Additionally, the

Gas sensing properties of nanocrystalline diamond at room temperature

• Marina Davydova,
• Pavel Kulha,
• Alexandr Laposa,
• Karel Hruska,
• Pavel Demo and
• Alexander Kromka

Beilstein J. Nanotechnol. 2014, 5, 2339–2345, doi:10.3762/bjnano.5.243

• Figure 5, exposure of the sensor elements to 100 ppm of ammonia gas led to increased impedances from 4.4 to 5.4 MΩ and from 3.9 to 5.4 MΩ for the samples nucleated for 1 min and 5 min, respectively. It should be noted that a variation (shift) in the starting impedance value was observed. The starting

• impedance varied by nearly an order of magnitude in some cases. The origin for this difference can be attributed to several factors, for example, low quality ohmic contacts or memory effects of the surface state of NCD. It was concluded that technological optimization is still required for achieving better

• conductive electrodes (Figure 7, cross-sectional view). Moreover, the impedance measurements showed that the gap between the interdigitated electrodes is one of the most important geometric parameters of the sensor and should carefully be considered when enhancing the sensing response (Figure 3 and Figure 5

Low cost, p-ZnO/n-Si, rectifying, nano heterojunction diode: Fabrication and electrical characterization

• Vinay Kabra,
• Lubna Aamir and
• M. M. Malik

Beilstein J. Nanotechnol. 2014, 5, 2216–2221, doi:10.3762/bjnano.5.230

• Equations 4–6 [9][10] as follows: where Vbi is the built-in voltage, Xn and Xp are the depletion width for the n- and p-side, and εn and εp are the dielectric constants of n-Si and p-ZnO, respectively. The dielectric constants εp and εn were found to be 7 and 11.7, respectively, as derived from impedance

• crystalline phase of the p-ZnO nanoparticles. The Hall effect measurement system (ECOPIA, model HMS-3000) was used for electrical characterization of the sample. An electrometer (KEITHLEY, 6517B) was used for the current–voltage (I–V) measurements of the diode and an impedance analyzer (WAYNE KERR, 6500B) was

Effect of channel length on the electrical response of carbon nanotube field-effect transistors to deoxyribonucleic acid hybridization

• Hari Krishna Salila Vijayalal Mohan,
• Jianing An,
• Yani Zhang,
• Chee How Wong and
• Lianxi Zheng

Beilstein J. Nanotechnol. 2014, 5, 2081–2091, doi:10.3762/bjnano.5.217

• contribution of charge-trapping mechanism to the observed behavior [27][28]. Similar DNA detection studies using CNTs based on the principle of impedance exhibited detection limits as low as 100 aM [29]. To verify whether the source of the signal is from the CNT channel, ID–VG curves of FETs with only the

Carbon-based smart nanomaterials in biomedicine and neuroengineering

• Antonina M. Monaco and
• Michele Giugliano

Beilstein J. Nanotechnol. 2014, 5, 1849–1863, doi:10.3762/bjnano.5.196

• smaller microelectrodes, reducing the electrode surface exposed to the electrolyte or in close proximity to neuronal cell membranes, has been shown to lead to a significant electrochemical impedance of the interface, decreased injected charge limits and poor S/N properties. CNTs, by their excellent

• ionic and electronic conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, with the high mechanical stability of CNTs. This combination, employed as a coating layer of conventional MEAs, resulted in reduced impedance, and thus in improved performances not only when compared

Experimental techniques for the characterization of carbon nanoparticles – a brief overview

• Wojciech Kempiński,
• Szymon Łoś,
• Mateusz Kempiński and
• Damian Markowski

Beilstein J. Nanotechnol. 2014, 5, 1760–1766, doi:10.3762/bjnano.5.186

• be attributed to the strained nano-graphite appearing in the sample. There are also other ways to determine the dimensions of the CNs. Among them are impedance measurements [32] and the EPR technique performed on the conducting electrons [33]. A more detailed analysis is provided in the next section