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Photochromic transitions in silver nanoparticles (AgNPs) embedded titanium dioxide (TiO2) films under green light illumination are marked by reduction in strength and blue shift in the position of the localized surface plasmon resonance (LSPR) associated with AgNPs. These transitions, which happen in the sub-nanometer length scale, have been analysed using the variations observed in the effective dielectric properties of the Ag-TiO2 nanocomposite films in response to the size reduction of AgNPs and subsequent changes in the surrounding medium due to photo-oxidation. Bergman- Milton formulation based on spectral density approach is used to extract dielectric properties and information about the geometrical distribution of the effective medium. Combined with finite element method simulations, we isolate the effects due to the change in average size of the nanoparticles and those due to the change in the dielectric function of the surrounding medium. By analysing the dynamics of photochromic transitions in the effective medium, we conclude that the observed blue shift in LSPR is mainly because of the change in the dielectric function of surrounding medium, while a shape-preserving effective size reduction of the AgNPs causes decrease in the strength of LSPR. [ABSTRACT FROM AUTHOR]

Label-free electrochemical immunosensors (EIs) are simple and sensitive in cancer diagnosis. Electrode materials which can offer a large specific area and excellent electrical conductivity play a critical role in the fabrication of EIs. In our study, ce-MoS2/AgNR composite was synthesized via Van der Waals force and electrostatic interaction between chemical exfoliated MoS2 nanosheets (ce-MoS2) and Ag nanorods (AgNRs). The conductivity of ce-MoS2/AgNR composite was almost three times higher than single ce-MoS2 because of the synergistic effect between ce-MoS2 and AgNRs. Furthermore, AgNRs could effectively inhibit the stacking of MoS2 nanosheets. The EIs for prostate-specific antigen (PSA) detection were fabricated based on ce-MoS2/AgNR composite. The fabricated EIs retained a wide linear response range (0.1–1000 ng/ml), low sensitivity (0.019 μA/(ng ml−1)), and low detection limit (0.051 ng/ml) for the detection of PSA. Therefore, the EIs based on screen-printed electrode (SPE) and ce-MoS2/AgNR composite could be applied to clinical diagnosis of prostatic cancer and have potential application in the detection of other cancer biomarkers. [ABSTRACT FROM AUTHOR]

Abstract Silver nanoparticle (AgNP)/carbon nanotube (CNT) composites are drawing increasing attention for several applications, especially where transparency is required. However, interfacial interaction and stability of the AgNP/CNT composites have been scarcely investigated. In the present study, transparent coatings were prepared from dispersed AgNP-coated multiwalled CNTs and exposed to different sintering conditions. The changes in surface morphology and evolution of interfacial configuration of AgNP-decorated CNT transparent composite films were investigated. Under certain conditions, CNT ropes were glued to one another by the melted AgNP aggregates, resulting in the improvement of the measured electrical properties. The in situ measurements of the electrical properties allowed correlating the AgNPs sintering mechanism with the morphological observations. Notably, at a given temperature, increasing the initial film density increased the time necessary to complete the AgNPs sintering. The obtained results show that the electrical resistance can be used as a tool to indirectly monitor the network state of transparent AgNP-decorated CNT composite films, hence paving the way to tuning the composite film properties with a high precision for the desired application. These findings also explain the mechanism of reinforcement of polymer nanocomposites by the current nanofillers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The structural, optical and electrical anisotropy of AgNW composite films. • The optical and electrical anisotropies are correlated to the angular distribution of nanowires. • The relationship between polarized transmittance and sheet resistance. Abstract Silver nanowire (AgNW)/polymer composite films fabricated by roll-to-roll slot die-coating exhibit optical and electrical anisotropy. To evaluate the dependence of the film's optical and electrical properties on the AgNW orientation, we quantify their polarized optical extinction and sheet resistance. Applying image analysis tools to microscope images, we show structural anisotropy due to a slightly preferential AgNW orientation. Optical anisotropy due to longitudinal- and transverse-mode surface plasmons resonances is predominantly observed in the lengthwise and crosswise direction of the composite films, respectively. Electrical anisotropy also depends on the measurement direction: sheet resistance is small in the lengthwise direction. These data indicate that the distribution of AgNWs is not fully isotropic, with their long axis preferentially oriented along the lengthwise direction of the composite films. Furthermore, although optical and electrical anisotropies are of comparable magnitude, both are smaller than the structural anisotropy. Optical anisotropy is still observed even when the amount of AgNWs increases, indicating that their orientation remains relatively constant. Electrical anisotropy is also preserved, indicating that junction resistance prevails in such composite films. The relationship between polarized transmittance and sheet resistance at a given measurement angle is consistent with a figure-of-merit equation often used for randomly-oriented AgNWs. [ABSTRACT FROM AUTHOR]

Abstract Flexible and transparent substrate materials were fabricated by using bacterial cellulose (BC), silk fibroin protein (SF) and/or polyvinyl alcohol (PVA). The BC-SF and BC-SF-PVA films obtained were further modified by impregnation with silver nanocubes (AgNC). The influences of the silver nanocubes and white light illumination on the electric and viscoelastic properties of the films were investigated. Complex conductivity measurements showed that the films with PVA component are more sensitive to light exposure and there is an increase in conductance when the sample is illuminated. The films that contained silver nanocubes showed higher values of specific susceptance than their unmodified counterparts. DMA analyses revealed that the storage shear moduli of the films increase with addition of silver nanocubes. It was also found that the relaxation transition observed at elevated temperatures in the BC-SF-PVA-AgNC films is highly sensitive to the light exposure. Above the glass transition of PVA, both storage- and loss-shear moduli change dramatically if the sample is illuminated during the measurements with respect to the case when it was kept in the dark. Highlights • Flexible transparent bacterial cellulose-silk fibroin-PVA films were prepared. • Impregnation with nanostructured silver affects the physical properties of the film. • The effects of the illumination on the properties of the films were studied. • High-temperature mechanical transition of the films is sensitive to light exposure. [ABSTRACT FROM AUTHOR]

Silver nanoparticle (AgNP) has wide-spread applications in photovoltaic cell, biological sensors, biomedical devices, surface enhanced Raman scattering (SERS) etc. which are intricately dependent on AgNP shape, size, concentration and aggregation states. Here, the particle size, shape and aggregation dependent dipole and quadrupole surface plasmon resonances are spectroscopically investigated by preparing AgNPs (diameter 10-110nm) using silver nitrate (AgNO3) and sodium borohydride (NaBH4 as reducing agent) in aqueous environment at 0 ∘C. The AgNP UV-Visible spectra showing plasmon-induced dipole and quadrupole modes are corroborated by the theoretical framework of Mie-Gans model and discrete dipole scattering model DDSCAT and different particle sizes, shapes and possible aggregation or clusterization are predicted. All the samples show presence of spherical and nonspherical distribution of AgNP. However, the concentration of nonspherical particle is more for higher concentration of reducing agent as is evidenced by the appearance of quadrapole absorption maxima. The minimum particle size is found at a particular ratio of concentration of AgNO3 and NaBH4. The day variation of AgNP kinetics also signalled the onset of quadrupole deformation of clusters. [ABSTRACT FROM AUTHOR]

Time-resolved polarization-dependent transient absorption has been used to study the plasmonicity of the optical transitions of Ag nanoparticles and nanoclusters. The lack of a measureable polarization anisotropy in the nanoparticles is indicative of the ultrafast electron-electron scattering while the anisotropy with a depolarization timescale of 500 fs observed in the nanoclusters indicates the excitation of a non-plasmonic state. The short lifetime of the anisotropy is a measure of electronic coupling between nearly degenerate states and is thus proposed as a sensitive measurement of the plasmonic content of the optical transitions of nanoclusters. [ABSTRACT FROM AUTHOR]

Crystalline quality and capping agent ratio are crucial to the electrical property of silver nanowires (AgNWs). In this paper, in order to achieve the high conductance, the crystalline quality of AgNWs was regulated by a comparative study of mediated ions Cu 2+ and Fe 3+ in polyol process, and the capping ratio of Poly(N-vinylpyrrolidone) (PVP) on the surface of AgNWs was intensively adjusted. The proper addition of Fe 3+ ions was a more favorable route to achieve AgNWs with fine crystallinity and uniform dimension, and a monolayer PVP capping on AgNWs surface was finally obtained. The as-prepared AgNWs was applied to formulate a conductive ink and then conductive tracks were formed on polymeric substrate after a mild temperature treatment. A high electrical conductivity of 3.93 × 10 5  S/cm and an outstanding bending resistance were achieved for these tracks. Moreover, 20 wt% AgNWs was embedded into polypyrrole (PPy) as a filler to form a flexible electromagnetic interference (EMI) shielding thin film. The AgNWs could greatly improve the conductivity of PPy film, and correspondingly the shielding effectiveness (SE T ) of PPy/AgNWs was almost 3.57 times higher than that of pure PPy. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are synthesized in a plasma electrochemical system with an aqueous solution of AgNO3 as anode. 5-Bromouracil, ethanol and dimethyl sulfoxide are added to the solutions for tuning the plasma-induced liquid chemistry. The characteristic localized surface plasmon resonance of the AgNPs is used to investigate the AgNPs formation process. The results indicate that there exists Ag+ reduction and Ag oxidation simultaneously during the AgNPs formation, and the hydrated electrons formed by the dissolution of plasma electrons are the main reducing agents for the Ag+ reduction, while the hydrogen peroxide produced by the plasma-liquid interactions plays a role in etching the formed AgNPs to Ag+. [ABSTRACT FROM AUTHOR]

Self-focusing of laser beam propagating through a dissipative suspension of metallic nanoparticles is studied. The impact of the imaginary part of nanoparticle polarizability on the optical force and consequently on the particles' rearrangement in the presence of laser fields with an initial Gaussian profile is considered. It is shown that the absorption of laser leads to the creation of optical force along the wave propagation direction which can cause longitudinal distribution of nanoparticles. Considering fifth order nonlinearity of wave amplitude that comes from the simultaneous considering of normal Kerr effect produced by the inhomogeneity of the refractive index resulted from the ponderomotive force acting on conducting electrons and artificial Kerr nonlinearity caused by the polarization optical force acting on electrically polarized particles, set of differential equations describing nonlinear steady-state evolution of laser beam is derived by using a non-paraxial method. Dynamics of laser for different frequencies is investigated and optimum frequency range for improving focusing property is determined. It is shown that the artificial Kerr effect causes localization of particles near the propagation axis that can substantially reduce the threshold power for occurring self-focusing in comparison with plasma and other rigid plasmonic systems. [ABSTRACT FROM AUTHOR]

We show that silver nanoparticles, which are deposited on a terahertz-receiving antenna, can be sintered by intense terahertz pulse irradiation. The conductance of the silver nanoparticles between the antenna electrodes is measured under the terahertz pulse irradiation. The dispersant materials surrounding the nanoparticles are peeled off, and conduction paths are created. We reveal that, during sintering, quantum point contacts are formed, leading to quantized conductance between the electrodes with the conductance quantum, which reflects the formation of atomically thin wires. The terahertz electric pulses are sufficiently intense to activate electromigration, i.e., transfer of kinetic energy from the electrons to the silver atoms. The silver atoms move and atomically thin wires form under the intense terahertz pulse irradiation. These findings may inspire nanoscale structural processing by terahertz pulse irradiation. [ABSTRACT FROM AUTHOR]

The behavior of silver nanoparticles (AgNPs) under an applied electric field depends primarily on their stabilizing agent. This research aimed at investigating the behavior of AgNPs and their stabilizers under the electrocoagulation (EC) process. In two separate experiments, sodium citrate and polyvinylpyrrolidone (PVP) were used as the nanoparticles’ stabilizers. Stability of the particles was studied while applying an electrical current with various voltages. Efficiency of the EC process was investigated for these different AgNPs sols. In the case of sodium citrate for various voltages, the plasmon resonance peak of the sample was disappeared after applying the electric field for 90 min, reflecting the removal of AgNPs in the sol by 99.91%. In the case of PVP for various voltages of the EC process for 10 min, the absorbance peak disappeared, and removal efficiency of AgNPs reached 99.98%. Effect of stabilizer concentration on the EC process was investigated. As sodium citrate concentration increased, the stability of AgNPs under an equall applied electric field increased, while the increase of the PVP concentration did not influence on the stability of AgNPs. Kinetic of AgNPs removal was also studied. [ABSTRACT FROM AUTHOR]

A new heterometallic compound AgPb(C2O4)(NO3) (AgPb-1) was constructed for the first time using a precipitation reaction. Then, different silver nanoparticles (Ag-NPs)-decorated lead compounds were obtained from AgPb-1via thermal annealing at different temperatures. The compounds Ag·PbCO3 (AgPb-2), Ag·α-PbO (AgPb-3), Ag·α-PbO + β-PbO (AgPb-4) and Ag·β-PbO (AgPb-5) were obtained by annealing at 523 K, 623 K, 723 K and 873 K, respectively. The formed powders were investigated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The dispersion of Ag-NPs on the surface of lead compounds as decorated layers was proven by SEM and TEM micrographs. The electrical conductivity and dielectric constant of the precursor in the temperature range of 293–673 K were investigated. Furthermore, the electrical behaviours of the different phases are described. [ABSTRACT FROM AUTHOR]

Resistive switching devices are being intensively studied aiming a large number of promising applications such as nonvolatile memories, artificial neural networks and sensors. Here, we show nanoscale bipolar resistive switching in Pt/Si/Ag/TiW structures, with a dielectric barrier thickness of 20 nm. The observed phenomenon is based on the formation/rupture of metallic Ag filaments in the otherwise insulating Si host material. No electroforming process was required to achieve resistive switching. We obtained average values of 0.23 V and −0.24 V for the Set and Reset voltages, respectively. The stability of the switching was observed for over 100 cycles, together with a clear separation of the ON (10 3 Ω) and OFF (10 2 Ω) states. Furthermore, the influence of the Set current compliance on the ON resistance, resistances ratio and Set/Reset voltages percentage variation was also studied. [ABSTRACT FROM AUTHOR]

We report that the single-molecule junction conductance of thiol-terminated silanes with Ag electrodes are higher than the conductance of those formed with Au electrodes. These results are in contrast to the trends in the metal work function Φ(Ag)<Φ(Au). As such, a better alignment of the Au Fermi level to the molecular orbital of silane that mediates charge transport would be expected. This conductance trend is reversed when we replace the thiols with amines, highlighting the impact of metal-S covalent and metal-NH2 dative bonds in controlling the molecular conductance. Density functional theory calculations elucidate the crucial role of the chemical linkers in determining the level alignment when molecules are attached to different metal contacts. We also demonstrate that conductance of thiol-terminated silanes with Pt electrodes is lower than the ones formed with Au and Ag electrodes, again in contrast to the trends in the metal work-functions. [ABSTRACT FROM AUTHOR]

This study explores, for the first time to our knowledge, the influence of electret state on the dielectric parameters of porous zeolite of frequencies up to 10 6 Hz, at room temperature and normal atmospheric pressure. The I-V characteristics with unusual hysteresis loop in the wide pressure range were measured on zeolite plates having three different material characteristics: A) plate, cut out from a monoblock natural zeolite; B) plate, modified by silver ions, and C) plate containing silver nanoparticles. Zeolite samples were exposed to an electric field (E p = 2 kV cm −1 ) in an air atmosphere for 240 min. It is established, that the stability of electret state and value of the dielectric response ε′ and ε″ for clinoptilolite Ag nanoparticles containing plates changed under influence of DC electric field. During some time the dielectric response is restored and observed unique phenomenon indicates on the electret behavior of clinoptilolite samples. These changes are observed within a few days consequently, there is long-term dynamics of the dielectric response changes. This interpretation is based on the assumption that due influence of the dc electric field part of the silver atoms in nanoparticles decays into ions and electrons. [ABSTRACT FROM AUTHOR]

Materials that are both stretchable and electrically conductive enable a broad spectrum of applications in sensing, actuating, electronics, optics and energy storage. The materials engineering concept of stretchable conductors is primarily based on combining nanowires, nanoribbons, nanoparticles, or nanocarbons with rubbery polymers to obtain composites with different abilities to transport charge and alter their nanoscale organization under strain. Although some of these composites reveal remarkably interesting multiscale reconfigurability and self-assembly phenomena, decreasing conductance with increased strain has restricted their widespread implementation. In a broader physical sense, the dependence of conductance on stress is undesirable because it requires a correlated change of electrical inputs. In this paper, we describe highly conductive and deformable sheets with a conductivity as high as 230 000 S cm-1, composed of silver nanoparticles, infiltrated within a porous aramid nanofiber (ANF) matrix. By forming a kirigami pattern, consisting of a regularized network of notches cut within the films, their ultimate tensile strain is improved from ~2% to beyond 100%. The use of ANFs derived from well-known ultrastrong KevlarTM fibers imparts high mechanical performance to the base composite. Importantly, the conductance of the films remains constant, even under large deformation resulting in a material with a zero conductance gradient. Unlike other nanocomposites for which strain and conductance are strongly coupled, the kirigami nanocomposite provides a pathway to demanding applications for flexible and stretchable electronics with power/voltage being unaffected by the deformation mode and temperature. [ABSTRACT FROM AUTHOR]

Polymer based composites with tunable dielectric properties have many applications in organic electronics. This manuscript reports the influence of gamma irradiation on the electrical and dielectric properties of silver/polymer composite (Ag/PVA) films with thickness 0.18 mm. The films were prepared by the in-situ chemical reduction and later irradiated with gamma (γ) radiation doses (25, 50, 75, 100, 125 KGy). The content of Ag (0.4 wt %) in the PVA films were determined by the atomic absorption spectroscopy (AA). The films were characterized by the dielectric spectroscopy and Current-Voltage (I V) measurements. The dielectric constant ( ε ′ ) value decreased with the increasing gamma irradiation doses. The conductivity films and dielectric loss increased with the increasing gamma irradiation doses. The optimum conductivity: σ = 4.9 × 10 −8 S m −1 was found at gamma radiation dose of 125 KGy. The Poole-Frenkel emission is the prevailing transport mechanism for all the samples. [ABSTRACT FROM AUTHOR]

Continuous silver shells were deposited on copper flakes using a two-stage precipitation process. A tightly packed layer of silver nanoparticles was first formed on the surface of the base metal by galvanic displacement. The size of the noble metal particles and their distribution on the substrate were controlled using complexing agents and dispersants. A continuous Ag deposit was subsequently grown by reducing slowly [Ag(NH 3 ) 2 ] + ions with glucose. The final shell thickness was controlled by varying the amount of metal deposited in the second step. The electrical properties of resulting silver coated copper flakes are comparable to those measured for silver flakes of similar size and aspect ratio. By preventing the oxidation of copper cores up to 400 °C, the hermetic noble metal shell dramatically extends the temperature range in which Ag/Cu flakes can successfully replace pure silver. [ABSTRACT FROM AUTHOR]

We present results from an installation of fully roll-to-roll printed and coated polymer solar cell modules in a greenhouse environment over the course of roughly 2 years (650 days). We explored two different device architectures based on either fully carbon-based electrodes or silver nanowire (AgNW)-based electrodes and two different barrier materials. We followed the ISOS protocols while studying the devices in three different greenhouse conditions in the Netherlands and compared to reference devices mounted outdoors in Denmark tested according to ISOS-O-1 and ISOS-O-2. We studied each condition and type in multiples to obtain acceptable statistics and found that the AgNW-based devices performed best in terms of stability. [ABSTRACT FROM AUTHOR]

A nanofiber membrane composed of poly(ε-caprolactone) (PCL), poly(vinyl pyrrolidone) (PVP), and silver nanoparticles was prepared via electrospinning technique. The morphology and structure of the PCL/PVP/Ag nanofibers composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The SEM images showed that various composites of PCL/PVP/Ag could be electrospun to yield continuous and uniform nanofibers. FTIR spectra indicated that the molecular interactions between PCL and PVP are weak. The hydrophilicity, mechanical property, and swelling behavior of the as-spun composites can be manipulated by altering the blend ratio of PCL/PVP. XRD patterns and XPS spectra showed that the Ag nanoparticles were dispersed in the PCL/PVP nanofiber composites; and the Ag nanoparticles endowed the PCL/PVP/Ag composite with antibacterial activities. The obtained PCL/PVP/Ag nanofiber composites with the morphology similar to that of native extracellular matrix have the potential to create a moist environment and to kill bacteria, which make it possible to be used for wound dressing application. POLYM. COMPOS., 37:2847-2854, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Silver nanowire-based flexible transparent electrodes have critical problem, in spite of their excellent electrical and optical properties, that the electrical conductance and transparency degrade within several days in air because of oxidation of silver. To prevent the degradation of the silver nanowire, we encapsulated Ag-NWs with thin TiO barrier. Bar-coated silver nanowires on flexible polymer substrate were laminated at 120 °C, followed by atomic layer deposition of TiO nanoshell. With 20 nm of TiO nanoshells on silver nanowires, the transparent electrode keeps its electrical and optical properties over 2 months. Moreover, the TiO-encapsulated silver nanowire-based transparent electrodes exhibit excellent bending durability. [ABSTRACT FROM AUTHOR]

Nanoparticles of silver and cadmium selenide are obtained by the method of synthesis in a flow of immiscible liquids (water/toluene, water/dodecane); these nanoparticles manifest, respectively, the effects of plasmon resonance and the spatial confinement of charge carriers. The reactor used is a polytetrafluoroethylene capillary with temperature-controlled sections for particle nucleation and growth with the supply of precursors using micropumps. The diameters of the particles are determined from absorbance spectra and are found to be 40 nm for Ag nanoparticles and 1-2 nm for CdSe nanoparticles (depending on the growth duration). [ABSTRACT FROM AUTHOR]

The present article reports on the alignment or orientation of a particular compound N(4-n-heptyloxy benzylidene)4´-n-butylaniline through dielectric study. The effect of using two different alignment layers (for homogenous alignment) and doping silver nanoparticles (0.25% by weight) on the behavior in dielectric property with varying temperature and biasing electric field was studied in terms of liquid crystal alignment or orientation using the mechanism proposed by earlier workers. The study includes the anomalous dielectric behavior in SmG phase by presenting a technique for the analysis of the absorption process, which exists only in SmG phase at fixed frequency while varying temperature, is also presented. [ABSTRACT FROM AUTHOR]

The electrocatalytic activity of silver particles supported on nitrogen-containing mesoporous carbon materials (NMC) was studied with a view to dioxygen reduction. Silver particles with controlled size and shape on the NMC were synthesized by a double-pulse electrodeposition technique. Changing the nucleation and growth potential as well as their growth times resulted in varied morphologies of the electrodeposited silver. The effect of the supporting material itself on the activity was assessed by employing variably pyrolyzed NMC supports. The associated kinetic parameters were evaluated by hydrodynamic measurements in alkaline medium. The dioxygen reduction activity was associated with the available surface area, which was determined by double-layer capacitance measurements. The stability of the catalyst was tested by chronoamperometric measurements both in the presence and absence of methanol. Elemental components were identified by X-ray diffraction and X-ray photoelectron spectroscopy techniques. [ABSTRACT FROM AUTHOR]

We report an effective method for fabricating highly transparent and stretchable large-area conducting films based on a directional arrangement of silver nanowires (AgNWs) driven by a shear force in a microliter-scale solution process. The thin conducting films with parallel AgNWs or cross-junctions of AgNWs are deposited on the coating substrate by dragging a microliter drop of the coating solution trapped between two plates. The optical and electrical properties of the AgNW thin films are finely tuned by varying the simple systematic parameters in the coating process. The transparent thin films with AgNW cross-junctions exhibit the superior electrical conductivity with a sheet resistance of 10 Ω sq-1 at a transmittance of 85% (λ = 550 nm), which is well described by the high ratio of DC to optical conductivity of 276 and percolation theory in a two-dimensional matrix model. This simple coating method enables the deposition of AgNW thin films with high optical transparency, flexibility, and stretchability directly on plastic substrates. [ABSTRACT FROM AUTHOR]

Electrode fouling and passivation is a substantial and inevitable limitation in electrochemical biosensing, and it is a great challenge to efficiently remove the contaminant without changing the surface structure and electrochemical performance. Herein, we propose a versatile and efficient strategy based on photocatalytic cleaning to construct renewable electrochemical sensors for cell analysis. This kind of sensor was fabricated by controllable assembly of reduced graphene oxide (RGO) and TiO2 to form a sandwiching RGO@TiO2 structure, followed by deposition of Au nanoparticles (NPs) onto the RGO shell. The Au NPs-RGO composite shell provides high electrochemical performance. Meanwhile, the encapsulated TiO2 ensures an excellent photocatalytic cleaning property. Application of this renewable microsensor for detection of nitric oxide (NO) release from cells demonstrates the great potential of this strategy in electrode regeneration and biosensing. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have attracted great attention due to its optical, electrical and thermal properties. Cellulosic supports for these nanoparticles are of particular interest because of its availability, flexibility and biocompatibility. In this work, AgNPs were synthesized using two cellulosic materials, cellophane (CP) and filter paper (FP), as matrix support. Cellulosic materials were immersed in an aqueous solution of silver nitrate containing polyvinylpyrrolidone (PVP) and then reduced with hydroxylamine. The obtained nanocomposites (CP-AgNPs and FP-AgNPs) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (DRX) and scanning electron microscopy (SEM). AgNPs of near 15 nm anchored onto cellulosic surfaces were detected. The thermal properties of these materials were investigated through thermogravimetry (TG). Their kinetic of thermal decomposition was studied by the Vyasovkin method of dynamic isoconvertion, which indicated a catalytic effect of AgNPs in the cellulose thermal decomposition reaction. [ABSTRACT FROM AUTHOR]

Based on the own experimental data and the literature ones, a supposed relationship between the polarities of esterified unsaturated higher fatty acids contained in the native lipids in the presence of silver nanoclusters and possible variations in the coordination numbers of separate silver atoms in these clusters participating in the π-complex formation is described. Some new molecular parameters for satisfactory description of the chromatographic behavior and the general physicochemical characteristics of unsaturated hydrocarbon chains as constituents of individual lipid molecules in the presence of silver compounds are proposed. Some variants of possible applications of complex organic structures including their polyatomic clusters are mentioned. [ABSTRACT FROM AUTHOR]

MeV carbon ion irradiation-induced changes in the electrical conductivity of Silver nanowire (Ag-NW) networks is demonstrated systematically at different C + ion fluences ranging from 1 × 10 12 to 1 × 10 16 ions/cm 2 at room temperature. At low C + ion fluences, the electrical conductivity of Ag-NWs decreases and subsequently increases with increase fluence. Finally, at high C + ion fluences, conductivity again decreases. The variation in the electrical conductivity of Ag NW network is discussed after analysis using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The observed increase in electrical conductivity is thought to be due to ion induced coalescence of Ag-NWs at contact position, which causes reduction of wire–wire contact resistance, while the decrease in electrical conductivity may be due to defect production by C + ions into Ag-NWs. Ion beam technology is therefore a very promising technology that is capable of fabricating highly conductive Ag-NW networks for transparent electrodes. Moreover, a method for thinning, slicing and cutting of Ag-NWs using ion beam technology is also reported. [ABSTRACT FROM AUTHOR]

In this paper, fully inkjet printed multilayer capacitors and inductors are fabricated and characterized using poly 4-vinylphenol (PVP) ink as the dielectric layer and silver nanoparticle ink as the conductor. Inkjet printed through vias, created with a novel dissolving method are used to make RF structures in a multilayer inkjet printing process. The vias have been realized in a 350-nm PVP film and exhibit resistance better than 0.1 $\Omega $ . Spiral inductors from 10 to 75 nH have been realized with maximum quality factors around five. The 10-nH inductor exhibits a self-resonant frequency slightly below 1 GHz. Metal–insulator–metal capacitors are realized with densities of 50 pF/mm ^{2} . These capacitors demonstrate values ranging from 16 to 50 pF. The 16-pF capacitor shows a self-resonant frequency over 1.5 GHz. The successful implementation of inductors and capacitors in an all inkjet printed multilayer process with vias is an important step toward fully inkjet-printed large area and flexible RF systems. [ABSTRACT FROM AUTHOR]

Silver nanoparticles were embedded in zinc oxide matrix by using sputtering-cum-evaporation technique. Particle size and metal volume fraction were tailored by varying the amount of silver in the Al-ZnO matrix. Strong surface plasmon resonance peak in the optical absorbance spectra was observed at ∼500 nm. Electrical conductivity was measured in the temperature range of 80-220 K when illuminated at 500 nm, and in dark to explain the observed transport processes associated with this material. [ABSTRACT FROM AUTHOR]

A practical and feasible bottom-up chemistry approach is demonstrated to dramatically enhance thermoelectric properties of the Bi2Te3 matrix by means of exotically introducing silver nanoparticles (AgNPs) for constructing thermoelectric composites with the hierarchical two-phased heterostructure. By regulating the content of AgNPs and fine-tuning the architecture of nanostructured thermoelectric materials, more heat-carrying phonons covering the broad phonon mean free path distribution range can be scattered. The results show that the uniformly dispersed AgNPs not only effectively suppress the growth of Bi2Te3 grains, but also introduce nanoscale precipitates and form new interfaces with the Bi2Te3 matrix, resulting in a hierarchical two-phased heterostructure, which causes intense scattering of phonons with multiscale mean free paths, and therefore significantly reduce the lattice thermal conductivity. Meanwhile, the improved power factor is maintained due to low-energy electron filtering and excellent electrical transport property of Ag itself. Consequently, the maximum ZT is amazingly found to be enhanced by 304% arising from the hierarchical heterostructure when the AgNPs content reaches 2.0 vol%. This study offers an easily scalable and low-cost route to construct a wide range of multiscale hierarchically heterostructured bulk composites with significant enhancement of thermoelectric performance. [ABSTRACT FROM AUTHOR]

Silver nanowires have drawn remarkable attention owing to their anisotropic electrical and optical properties that differ from those observed in the bulk materials and the interesting applications in various areas such as electronic devices, chemical sensors and photonics. In this paper, silver nanowires with an average diameter of 450 nm and a length of up to 100 μm were successfully synthesized by a polyol process. The experimental results indicate that the morphologies and sintering behaviors of silver nanowires are impacted by glutaric acid and the sintering temperature. The isotropically conductive adhesives (ICAs) were made by adding silver nanowires to the polymer composites consisted mainly of epoxy resin, cure agent and catalyst, and then the electrical properties were investigated based on those physical parameters such like the fraction of the silver nanowires of the total of silver fillers and the curing temperature. The in situ monitoring of the variation in electrical resistance of the ICAs and DSC explore that silver nanowires can affect the curing behavior of the ICAs. Silver nanowires can significantly improve the electrical conductivity of the ICAs when the loading of silver nanowires is low and the curing temperature is less than about 250 °C. There is little difference of the electrical resistivity between the ICAs filled with silver nanowires and micro-sized silver flakes when the loading of silver fillers in the ICAs is 75 wt%, and this phenomenon is related to the curing temperature. The silver nanowires treated by glutaric acid can improve the electrical property of the ICAs. [ABSTRACT FROM AUTHOR]

Nanoparticle-based flexible field-effect transistors (FETs) containing carbon nanotubes (CNTs) and silicon nanowires (SiNWs) have attracted tremendous attention, since their interesting device performance can be utilized for integrated nanoscale electronics. However, use of CNTs and SiNWs on polymer substrates poses serious limitations in terms of their fabrication procedure, repeatability, and biodegradability. In this article, we report for the first time the fabrication and characteristics of solution-processed FETs on a paper substrate doped with easily prepared silver nanoparticles (AgNPs). To compare the FET performance, we fabricated two other FETs on paper containing ionic liquid (IL, 1-butyl-3-methylimidazolium octyl sulfate) and reduced graphene oxide (rGO) as dopants. We observe that the AgNP-based dopant generated good FET characteristics in terms of linear transconductance variations and higher carrier concentration values, showing negligible changes after bending and aging. In comparison with the AgNP-FET, the rGO- and IL-based dopants yielded high carrier mobilities, but the rGO-based FET is more susceptible to aging and bending. The excellent linearity of the I- V curve found for the AgNP-FET ensures its applicability for devices requiring linear transfer characteristics such as linear amplifiers. [ABSTRACT FROM AUTHOR]

Large-scale silver nanowires (AgNWs) with a width of 50-60 nm and a typical length of 10 ± 5 μm were synthesized conveniently through a simple polyol reduction method, and the weight of obtained AgNWs was close to 10 g in this one-pot reaction with 500 ml of solution. The as-prepared AgNWs were incorporated into polyvinylidene fluoride matrix (PVDF) to fabricate the AgNWs/PVDF composites, and dielectric behaviors of the composites were investigated. The results revealed that a low percolation threshold of 1.8 vol% was observed in the AgNWs/PVDF composites, which was due to the large aspect ratio of one-dimension structured AgNWs. A giant dielectric constant of 80,000 at 1 kHz was obtained with 1.8 vol% of AgNWs mainly caused by the percolation effect. Besides, the large micro-capacitor networks and strong interfacial polarization at percolation threshold contributed to the enhanced dielectric constant. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have been synthesized using maltose as reducing agent and microwave heating as reaction initiator. The nanoparticles are studied for their optical, structural, thermal, zeta potential and electrical properties. The synthesis protocol used is fast and resulted in the formation of multi-shaped AgNPs as indicated by their optical response and TEM. The crystallite size of nanoparticles and strain of the sample was found to be around 39 nm, and 2.3 × 10, respectively, as calculated from XRD data. Zeta potential and electrical response both showed almost threefold increase for multi-shaped as compared to isotropic nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, we achieved an enhancement of the transmission surface plasmon resonance (T-SPR) intensity by depositing silver nanoparticles (AgNPs) onto a gold grating substrate. The T-SPR spectrum of the gold grating substrate with AgNPs showed a strong and narrow SPR peak located between 650 and 800 nm; the maximum SPR excitation was observed at a 35° angle of incidence. We controlled the distance between the gold grating surface and the AgNPs by using layer-by-layer (LbL) ultrathin films of poly(diallydimethylammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS) to study the distance dependence of the coupling effect between the AgNPs and the gold grating substrate. The distance-dependent T-SPR response of peak position and intensity showed distinctive changes when the intermediate layer was 10 bilayers (∼17 nm) thick. The strongest coupling surface plasmon excitation between the AgNPs and the gold grating substrate was obtained at this layer spacing. Furthermore, we explored the potential of the developed system as a switchable pH sensor. The T-SPR spectrum sensitively changed as the pH switched from acidic (pH 2) to alkaline (pH 12) conditions by the swelling/shrinking of the poly(allylamine hydrochloride) (PAH)/PSS LbL film, respectively, which was deposited between the AgNPs and the gold grating. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reliable green synthesis of silver nanoparticles (AgNPs) by cashew nutshells. [•] Green synthesis of AgNPs by cashew nutshells. [•] Higher temperatures speed up the synthesis of AgNPs by cashew nutshells. [•] Size-controlled synthesis of AgNPs by cashew nutshells. [•] Antifungal activity of AgNPs greenly synthesized by cashew nutshells. [ABSTRACT FROM AUTHOR]

Ag nanoparticles (Ag NPs) embedded titanium dioxide (TiO2) nanofibers were fabricated by colloidal sol process, electrospinning, and calcination technique. Calcination of the electrospun nanofibers were heat treated at 600°C for 180 minutes in air atmosphere. X-ray diffraction patterns exhibited that the anatase phase and silver coexisted in the resulted Ag NPs/TiO2nanofibers; transmission electron microscopy demonstrated Ag NPs well spread in the porous microstructure of composite fibers. The prepared nanofibers were utilized as photocatalyst for degradation of methyl orange. The degradation rate of methyl orange dye solution containing Ag/TiO2composite nanofibers is 99% only after irradiation for 3 hours. It is proposed that these new Ag NPs/TiO2composite nanofibers will have potential application in water pollution treatment. [ABSTRACT FROM AUTHOR]

A hybrid approach for the realization of In-free transparent conductive layers based on a composite of a mesh of silver nanowires (NWs) and a conductive metal-oxide is demonstrated. As metal-oxide room-temperature-processed sol-gel SnO x or Al:ZnO prepared by low-temperature (100 °C) atomic layer deposition is used, respectively. In this concept, the metal-oxide is intended to fuse the wires together and also to 'glue' them to the substrate. As a result, a low sheet resistance down to 5.2 Ω sq-1 is achieved with a concomitant average transmission of 87%. The adhesion of the NWs to the substrate is significantly improved and the resulting composites withstand adhesion tests without loss in conductivity. Owing to the low processing temperatures, this concept allows highly robust, highly conductive, and transparent coatings even on top of temperature sensitive objects, for example, polymer foils, organic devices. These Indium- and PEDOT:PSS-free hybrid layers are successfully implemented as transparent top-electrodes in efficient all-solution-processed semitransparent organic solar cells. It is obvious that this approach is not limited to organic solar cells but will generally be applicable in devices which require transparent electrodes. [ABSTRACT FROM AUTHOR]

Nano Ag-enhanced energy conversion efficiency (ECE) in one standard commercial pc-Si solar cell utilizing the forward scattering by Ag nanoparticles on surface has been researched experimentally and simulatively in this paper. Directly assembling Ag nanoparticles (with size about 100 nm) on the surface, it is found when the particle surface coverage is 10%, the ECE and the short circuit current density are increased by 2.8% and 1.4%, respectively. Without changing any existing structure of the ready-made solar cell, this facile and efficient method has huger applications than other methods. [ABSTRACT FROM AUTHOR]

The electrochemistry of silver nanoparticles contained in a consumer product has been studied. The redox properties of silver particles in a commercially available disinfectant cleaning spray were investigated via cyclic voltammetry before particle-impact voltammetry was used to detect single particles in both a typical aqueous electrolyte and authentic seawater media. We show that particle-impact voltammetry is a promising method for the detection of nanoparticles that have leached into the environment from consumer products, which is an important development for the determination of risks associated with the incorporation of nanotechnology into everyday products. [ABSTRACT FROM AUTHOR]

Abstract: Silver-nanoparticles-decorated reduced graphene oxide (rGO) was electrodeposited on indium tin oxide (ITO) by a cyclic voltammetry method. The results of X-ray diffraction, Fourier-transform infrared transmission spectroscopy and Raman spectroscopy confirmed the simultaneous formation of cubic phase silver nanoparticles and reduction of GO through the electrodeposition process. Field emission scanning electron microscope images showed a uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution on the RGO sheets, which could only be achieved using silver ammonia complex instead of silver nitrate as precursor. The composite deposited on ITO exhibited notable electrocatalytic activity for the reduction of H2O2, leading to an enzymeless electrochemical sensor with a fast amperometric response time less than 2s. The corresponding calibration curve of the current response showed a linear detection range of 0.1–100mM (R 2 =0.9992) while the limit of detection was estimated to be 5μM. [Copyright &y& Elsevier]

The silver nanoparticles doped poly-glycine composite membrane was prepared by cyclic voltammetry on the surface of the glassy carbon electrode (GCE). The morphology and electrochemical properties were characterized by scanning electron microscopy and cyclic voltammetry, respectively, and in detail, the electrochemical behaviors of the norepinephrine (NE) on this membrane were studied. The results showed that the membrane had good catalytic properties for the oxidative-reductive reaction of NE. NE had a couple of sensitive oxidative-reductive current peaks. The reductive peak currents were linearly with its concentration in the range of 1.90 × 10 to 7.00 × 10 and 7.00 × 10 to 1.00 × 10 mol l, and the linear regressive equations were i (A) = 3.73 × 10 + 0.70 C (mol l), i (A) = 9.83 × 10 + 0.12 C (mol l), respectively, with the relate coefficient ( r) of 0.9926 and 0.9944. The detection limit was 1.2 × 10 mol l (S/N = 3), which could be used to determine the content of NE and at the same time, eliminate the interference of the ascorbic acid (AA). The proposed method had high sensitivity, good selectivity and stability. [ABSTRACT FROM AUTHOR]

Abstract: In the present work we study, employing a tight-binding Hamiltonian, the influence of chemical disorder on the electronic level spacing distribution of a silver nanoparticle containing 5083 atoms ( 5.5nm). This nanoparticle was obtained by molecular dynamics simulations with a tight-binding atomic potential. The results indicate that in the absence of disorder the level spacing distributions are similar to those expected for systems belonging to the Gaussian Orthogonal Ensemble. Whereas, after increasing the chemical disorder, the electronic level spacing distribution and the statistics tend to the corresponding form for the Poisson Ensemble, i.e., the silver nanoparticle acquires an insulating character which is expected for strongly disordered systems. Hence, this kind of disorder produces the localization of the electronic states of the nanoparticle. [Copyright &y& Elsevier]

The domain kinetics during cyclic switching using electrodes of stable suspension of Ag nanoparticles and tap water was studied in single crystals of the relaxor ferroelectric strontium-barium niobate Sr0.61Ba0.39Nb2O6. Mathematical treatment of the set of instantaneous domain images and analysis of the switching current data by Kolmogorov-Avrami formula have been applied for characterization of the polarization reversal process. The change of the time constants during cyclic switching in the single domain area and the area with initial nanodomain structure has been attributed to relaxation of the bias field. The noticeable switching deceleration for suspension electrode was attributed to series resistance. [ABSTRACT FROM AUTHOR]

The determination of nitroaromatic compounds in aqueous solution was investigated at β-cyclodextrin (β-CD)/silver nanoparticle (AgNPs) composite modified ITO electrodes. This method relies on the different reduction potentials for the various nitroaromatic isomers, the different binding strengths of the nitroaromatic isomer guests to the β-CD host, and excellent electron transfer ability of AgNPs. After incubation in a solution with different single nitroaromatic compounds, reduction peaks in the range from -550 to -913 mV were observed at the modified electrode, depending on the nitroaromatic compound present. The sensor exhibited selectivity for some isomers in a solution containing a mixture of nitroaromatic compounds. In particular, the sensor shows specificity for 4-nitroaniline and 1-chloro-2-nitrobenzene over other nitroaniline isomers and nitrochlorobenzene isomers, respectively. The results show that all the nitroaromatic compounds, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 1-chloro-2-nitrobenzene, 1-chloro-3-nitrobenzene, and 1-chloro-4-nitrobenzene, could not only be detected but the electrode demonstrated a preference for the more strongly complexing species. [ABSTRACT FROM AUTHOR]

Silver polyhedron coated electrospun nylon 6 nanofibrous membranes were produced using a nonhazardous and 'green' electroless process. The process employed sodium citrate as a complexing and reducing agent at 80°C, without the need of any surfactant or hazardous chemicals. The novel nanofibrous membrane, produced under optimum conditions, demonstrated high infrared (IR) extinction and ultraviolet (UV) blocking and good water vapor permeability. It is expected to have wide potential application for thermal radiation shielding, UV blocking and IR camouflage. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

The electrical explosion of wires was used to prepare titanium dioxide nanopowders alloyed with silver nanoparticles. The photoelectrochemical properties and electronic structure of these materials were studied. The quantum yield for the photoelectrochemical current η and the flat band potential E for TiO/Ag films were found to be proportional to the content of the Ag phase on the electrode surface. [ABSTRACT FROM AUTHOR]