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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]

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]

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]

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]

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]

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]

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]