Ag3O was synthesized by jet-milling magnetron-sputtered Ag–Ag2O thin films. Heating the jet-milled powders in air and N2 from 40 to 148 °C at ambient pressure produced Ag3O-rich powders. The phase composition and unit-cell parameters of the jet-milled powders were measured as a function of temperature with in situ X-ray powder diffraction experiments from −186 to 293 °C. Ag3O was also produced by ball milling and sonicating jet-milled films at ambient conditions. The phase composition, unit-cell parameters, and thermal-reaction rates indicate nonstoichiometric Ag3O was produced from the reaction of metastable, nonstoichiometric Ag2O (cuprite structure) and ccp Ag. The thermal expansion of Ag3O is anisotropic; below 25 °C, the a-axis expansion is about twice the c-axis expansion resulting in a negative slope of c/a(T). The reversal of the sign of c/a(T) near 25 °C is dramatic. The thermal reaction is arrested when the temperature is rapidly increased from ambient to 130 °C. Ag3O is metastable and decreases its unit-cell volume during kinetic decomposition to Ag when heated above ambient temperature in air and nitrogen. The relative volume expansion of Ag3O is about 80% less than Ag at room temperature and below. The suite of nonstoichiometric Ag3O produced by heating displays a linear relation between c/a and unit-cell volume at room temperature. The c/a and unit-cell volume of a hydrothermally grown Ag3O single crystal reported in a published structure determination was the Ag-rich, low-volume end member of the linear series. The c/a and unit-cell volume are sensitive indicators of the oxygen content and state of disorder.

In recent times, nanotechnology has drawn the attention of the scientific community because of the wide variety of applications that can be done with it, from food packaging to targeted drug delivery; the use of nanoparticles has been a breakthrough in science that has now reached the market. Silver nanoparticles (Ag NPs) have unique properties due to the oscillation of electrons in the superficial plasmon. These nanostructures have been used in different applications in the area of nanomedicine, such as: targeted drug delivery, sensing and imaging, anti-fungal, anti-cancerous and biosensors. It has become evident that pathogenic bacteria are resisting antibiotics such as Penicillin becoming one of the most worrying topics in the world. People in the science community fear the day when we no longer can use these antibiotics, because the resistance of bacteria became too great, leaving us defenceless against any type of pathogens and possibly causing a catastrophe. However, we theorize that the possible solution to this problem could be the use of silver nanoparticles, given that there has not been a documented bacterial adaptation strategy that could give them resistance to Ag NPs. The purpose of this study is to find how the water-stable silver nanoparticles interact with different strains, including Gram negative and Gram-positive bacteria. The main objectives of our research were to synthesize and characterize water stable silver nanoparticles and test their potential bactericidal activity. We synthesized our Ag NPs using sodium citrate as a reducing agent. After synthesizing the nanoparticles, their optical properties were characterized by Ultraviolet-visible spectroscopy (UV-Vis); crystalline structure was evaluated with Electron Diffraction (ED) and X-Ray Diffraction (XRD); morphology was assessed by High Resolution Transmission Electron Microscopy (HR-TEM). Fourier Transform Infra-Red Spectroscopy (FT-IR) was used to indicate functional groups involved in the nanoparticle capping. Cultures were prepared with agarose and inoculated with the following bacterial strains: Bacillus cereus (Gram +), Micrococcus luteus (Gram +), Staphylococcus aureus (Gram +), Escherichia coli (Gram -), Citrobacter freundii (Gram -), Enterobacter aerogenes (Gram -), Klebsiella pneumoniae (Gram -), Proteus mirabilis (Gram -), Proteus vulgaris (Gram -) and Serratia marcescens (Gram -). Preliminary tests showed an inhibition diameter that surpassed 1.0 cm in all bacterial strains. We expect our Ag NPs to have a potential antibacterial activity towards all types of bacteria, due to oxidation of silver (Ag0 to Ag+).

Silver nanoparticles (Ag NPs) have unique optical, electrical, and thermal properties and are being incorporated into products that range from photovoltaics to biological and chemical sensors. The production of silver nanoparticles has been increasing worldwide in the nanotechnology industry due to the variety of applications and are very likely to reach aquatic ecosystems damaging them. Due to their small size and high surface area to volume ratio of NPs, they can strongly interact with life cells and cause damage to tested animals. Based on the mentioned previously, it is necessary to evaluate the silver nanoparticle nanotoxicity in aquatic ecosystems to prevent possible ingestion or transfer to humans. Also, the research will benefit aquatic systems due to less pollution around aquatic organisms. The objectives of this research included: i) production and characterization of stable silver nanoparticles in water, ii) characterizing the optical properties by UV-Vis spectroscopy and morphology by HR-TEM and; iii) evaluate the toxicity of silver nanoparticles in aquatic organisms, i.e Artemia salina. Results obtained evidenced that Ag NPs showed an intense absorption peak at 448 nm. This broad peak is due to the phenomenon called surface plasmon resonance (SPR) that is responsible for a variety of phenomena, including nanoscale optical focusing, negative refraction, and surface-enhanced Raman scattering. HR-TEM measurements evidenced the spherical form of the nanoparticles and its small size at around 12-20 nm. In addition, Electron Diffraction analyses suggested the composition of the nanoparticle, which contained only Ag0. The toxicity assays were evaluated using different concentrations of purified Ag NPs. During the cytotoxicity assay, it was demonstrated that Ag NPs were not toxic to Artemia salina after 24 and 48 hours of exposure. However, silver (as silver nitrate) evidenced high toxicity to Artemia salina at larval stage.

Functional polymers were previously employed to minimize the susceptibility of metallic nanoparticles (MNPs) for aggregation. Herein, we intended to conjugate catechol moiety into the polymer chain end considering its anchoring ability to virtually most surfaces. Accordingly, catechol end-functionalized polysarcosine (cat-PSar) was successfully prepared from the ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCA) using dopamine hydrochloride initiator. ROP of Sar-NCA was carried out at different monomer to initiator feed ratios. The molecular structure of cat-PSar was confirmed by 1H NMR and MALDITOF. Afterward, the obtained catechol functionalized polymer was used for in-situ synthesis and stabilization of silver nanoparticles (Ag-NPs) in aqueous solution. The observed characteristic absorption peak at λmax of 415 nm indicates the formation of Ag-NPs. Scanning electron microscope (SEM) images also elucidate the formation of Ag-NPs with the relatively small sizes of the nanocomposite at a high concentration of silver nitrate. Hence, biomimetic polymers could play a dual role as reducing and stabilizing agents in the preparation of monodispersed MNPs.

Silver/titanium dioxide (Ag/TiO2) membranes were successfully deposited on poly(sulfone amide) substrates by direct current magnetron sputtering and radio frequency magnetron sputtering techniques with pure silver (Ag) and TiO2 targets. The prepared membranes were systematically characterized by scanning electron microscopy X-ray diffraction, insulation tests, and Fourier transform infrared spectrometry. The dependence of the main sputtering parameters on optical and thermal properties of the film was investigated by an orthogonal analysis method. Optimal parameters of fabricate Ag/TiO2 membranes with better comprehensive performances could be obtained ultimately. The infrared reflection rate and temperature difference of the Ag/TiO2 film deposited with the optimized parameters were 81.6% and 90 °C, respectively. The high infrared reflection and excellent thermal conductivity properties of the Ag/TiO2 composite membrane make it a promising candidate for thermal insulating coatings on fabrics, and can be used for the development of high-performance protective garments in the future.

Glasses were prepared in systems based on two stoichiometric sulfides that were selected from Ga2S3, GeS2, and Sb2S3, with the incorporation of excess sulfur and CsCl. We investigated the fundamental properties, including glass transition, density, and optical absorption, and their variations with the incorporation of excess sulfur and CsCl into the pseudo two-component sulfide glasses. The incorporation of CsCl into the GeS2–Sb2S3 glasses shifted the absorption edge at the short-wavelength side to the long-wavelength direction, particularly for glasses with more amount of GeS2 than SbS3/2. In both cases of CsCl incorporation into the Ga2S3–GeS2 glass and Ga2S3–Sb2S3 glass systems, the absorption edges shifted to the short-wavelength direction regardless of the compositions. Ag photodoping behaviors were investigated for the bulk sulfide glasses with excess sulfur and CsCl. The results are discussed based on the diffusion of silver in the glass network that is modified by the incorporation.

The antibacterial hydrogels can be widely used in the biomedical area owing to their excellent properties. The main limitation of antibacterial hydrogels is their poor mechanical strength. In this study, the novel hydrogels were fabricated with a mixture of silk fibroin (SF), chitosan (CH), agarose (AG), and silver nanoparticles (SNPs) via facile reaction condition without inorganic substances. The mechanical property of these fabricated hydrogels can be modulated by the concentration of SF or AG. The rheological studies demonstrated enhanced elasticity of CH-doped hydrogels. Because of the presence of CH and Ag in hydrogels, the antimicrobial property against gram-positive and gram-negative bacteria was exhibited. Cytocompatibility test proved the very low toxic nature of the hydrogels. In addition, these composite hydrogels have a smaller porosity, higher swelling ratio, and good compatibility, indicating their great potential for biomedical application.

Conventional methods for determination of trace drug residues are either time consuming or labor intensive or require large specialized instruments, which hamper their practical applications in field analysis. Here, we present a rapid and quantitative surface-enhanced Raman scattering (SERS) detection method coupled with a portable Raman spectrometer for determination of trace drug residues on fish surface. Graphene oxide (GO) decorated popcorn-like Ag nanoparticles (NPs) on Cu plate (GO/AgNPs/Cu) were fabricated by a facile approach and directly employed as a robust SERS detection substrate. For practical SERS detections, trace-level residues of crystal violet (10−8 M, 4.1 ng/g) and malachite green (10−8 M, 3.6 ng/g) could be readily detected by simply swabbing the contaminated fish scale surface with the SERS substrate. Importantly, SERS detection was quantitatively realized in the broad linear concentrations. Compared with lab-based Raman spectrometer with large footprints, our method has potential applications in practical rapid, accurate, and on-site SERS determination.

Durable antibacterial PAN/Ag NPs nanofiber membrane was prepared by electrospinning. In this study, Ag NPs were composed by applying polyvinyl pyrrolidone as a dispersant and sodium borohydride (NaBH4) as a reductant. The composite nanofiber films and silver nanoparticles were characterized and tested by transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and Brunauer Emmett Teller (BET) and thermogravimetric analysis test. The specific surface area of PAN/Ag NPs (1%) and PAN/Ag NPs (3%) nanofiber membrane were about 25.00 m2/g calculated by the BET equation. It can be seen that the pore sizes of PAN, PAN/Ag NPs (1%), and PAN/Ag NPs (3%) nanofiber membranes were mainly distributed between 30 and 40 nm. The maximum removal rate of PM10, PM2.5, and PM1.0 was about 94%, 89%, and 82%, respectively, indicating it has a good filtering effect. The results also demonstrated that this membrane has bacterial reduction of over 99.9% for E. coli and S. aureus, respectively. In addition, the thermal stability of the fiber membrane with Ag NPs has no clear difference when compared to pure PAN nanofiber membrane and also has better moisture conductivity, indicating it is a potential candidate applied in biopharmaceutical antiseptic protection products.

Antimicrobial textiles received considerable attention due to public health and personal hygiene concerns. On the other hand, pathogenic microorganisms gain immunity against existing antibacterial products. For these reasons, new and stronger antibacterial agents need to be developed immediately. In this work, silver nanowires (Ag NWs) were decorated onto conventional fabrics via facile and scalable dip and dry method. Antimicrobial activity of the nanowire-decorated fabrics was investigated against a Gram-positive coccus (Staphylococcus aureus), a Gram-negative bacillus (Escherichia coli), a Gram-positive and spore-forming bacillus (Bacillus cereus), and a yeast-like fungus (Candida albicans) via disk diffusion and time–dependent killing methods. The effect of Ag NW content was investigated, and the decorated fabrics showed promising antibacterial activity even with a small amount of Ag NW decoration (0.095 mg/cm2). Moreover, decorated fabrics maintained their activity for 24 h. This work shows that Ag NW-modified fabrics can be used as antimicrobial textiles against a wide spectrum of bacteria.

This study aims at establishing environmentally stable and viable silver nanowire (AgNW) electrodes of an Electrodynamic Screen (EDS) film, by the inclusion of one or more protective layers of zinc oxide (ZnO) produced in lab by combining tetrahydrofuran (THF) and diethylzinc (DEZ). The electrodes can be realized as 1) stacked structure where the AgNW electrode has a layer of ZnO on top for protection or 2) sandwiched structure where the AgNW electrode is covered by ZnO layers, protecting it from the top and bottom. Experiments are done to test the effect of accelerated exposure to ultraviolet light, high temperature and passage of high voltage on the AgNW samples and are compared with the results obtained from the AgNW samples that have the ZnO protective layer which have also been subjected to the aforementioned test conditions. A complete water immersion test is performed in order to ensure functionality and efficiency of the ZnO/AgNW samples that are to be patterned as electrodes of the EDS film. This will demonstrate viability of the structure in the case of rain.

In order to understand the impact of nano-crystallites on current transport mechanisms in screen-printed c-Si solar cells with lowly-doped emitter, Te-glass based Ag pastes with different transition temperatures (Tg) were used. The Te-glass with lower Tg showed lower Rc than the one with higher Tg due to the formation of nano-crystallites in the glass layer. These nano-crystallites enhance the conductivity of the glass and lead to higher fill factor (FF). The nature of these nano-crystallites was first identified by the Raman spectrometry and the peaks at 76 cm-1, 119 cm-1 and 145 cm-1 were corresponding to Ag2Te and PbTe. The conductive-AFM further confirmed the high conductivity of these nano-crystallites without pyramidal Ag crystallites, which means the current transporting from Si emitter to Ag gridlines is mainly through the nano-crystallites in the glass.

The effect of surface-enhanced Raman spectroscopy (SERS) was investigated in N719 dye thin films deposited on silicon wafer with a thin film of silver nanoparticles (Ag-NPs) fabricated by laser ablation in an aqueous solution, using a NdYAG laser (λ = 1064nm). Optical absorption spectroscopy of the Ag-NPs colloidal solution shows an absorption peak at λ = 400nm, associated with a localized surface plasmon resonance in the Ag-NPs. Scanning electron microscopy (SEM) reveals that these NPs have an approximately spherical shape, with their diameter being tunable by laser power intensity. Raman spectroscopy measurements were performed using low laser power to avoid damage to the N719 dye films. Thus, a small Raman signal is obtained. The Raman intensity was greatly increased when the N719 film was deposited on a substrate with a thin film of Ag-NPs due to the SERS effect. The process was also used in Rhodamine-B to clearly demonstrate the SERS effect obtained by the use of these NPs produced by laser ablation.

In this study, silver, zinc and copper nanoparticles, AgNPs, ZnNPs and CuNPs, were tested on photodegradation using phenol as a model contaminant. The nanoparticles were phytosynthesized from an aqueous extract of Eichhornia crassipes leaves, and were characterized by UV-visible spectroscopy, EDS (Dispersive Energy X-ray Spectroscopy), SEM (Scanning Electron Microscopy), and TEM (Transmission Electron Microscopy). The AgNPs, ZnNPs and CuNPs showed a characteristic plasmon determined by UV-Vis; in the case of the EDS analyses Ag, Zn and Cu were detected as the main components. The detected composition by TEM corresponded to a metallic oxide for the three nanoparticles. Finally, for the photocatalytic performance on the phenol degradation under UV radiation, they showed about 50%, 52% and 34% with a 10 mg/L phenol solution that was achieved within 200 min using AgNPs, ZnNPs and CuNPs, respectively.

Data on the distribution of the precious metals (Au, Ag and the platinum=group elements Ru, Rh, Pd, Os, Ir, Pt) are rapidly accumulating as a consequence of the application of microbeam analytical techniques such as the electron microprobe, the proton microprobe, and the ion microprobe. The new data obtained with these techniques build on knowledge accumulated over the last 140 years using bulk analytical methods (e.g. spectrographic). The nature of the occurrence, the concentrations, and the variation in amount s of precious metals in minerals and mineral products are reviewed with comments as to the significance of the results with respect to industrial and environmental concerns. Future directions in mineral-specific analysis of trace precious-metal concentrations and applications outside of process mineralogy are discussed.

Extreme silver enrichment at the surface of the complex sulphide, tennantite (ideal formula: Cu12As4S13), occurs following exposure to alkaline solutions, and involves the development of an Ag-rich sulphide surface species. The tennantite has a low bulk Ag content of 0.3 at.%, and a percentage surface enrichment of Ag is thirty-six times that of the bulk. The techniques of X-ray photoelectron spectroscopy (XPS) and reflection extended X-ray absorption fine structure spectroscopy show the new phase to be a Ag sulphide species compositionally similar to cupriferous proustite ((Cu,Ag)3AsS3). Solution experiments and XPS depth profiling show that the surface is most depleted in Cu and Zn, and enriched in Ag compared to the bulk tennantite. Selective dissolution and reprecipitation at the tennantite surface cannot explain the enrichment of Ag relative to the bulk. Migration must have occurred and could have been driven by the leaching out of Cu which produces a metal-depleted surface, coupled to the relative incompatibility of Ag in the tennantite lattice. To account for the extreme enrichment at the surface, Ag must have diffused from depths of up to 9 nm, probably via structural weaknesses and vacancies in the tennantite lattice.

The crystal structure of stephanite fromthe type locality, Freiberg District, Saxony, Germany, was refined in the space group Cmc21, up to a final R index of 0.0427. Unit-cell parameters are: a 7.8329(6) Å, b 12.458(1) Å, c 8.5272(7) Å, V 832.1(1) Å3; Z = 4. The previously reported structural model is confirmed, but a higher-precision refinement was achieved herein by the introduction of thirdorder non-harmonic Gram-Charlier tensors for one Ag atom. In the structure of stephanite, Sb forms isolated SbS3 pyramids, which typically occur in sulphosalts, and Ag occupies sites with coordination ranging fromtriangular to almost tetrahedral. Both the Sb–S and Ag–S bond distances closely match the values commonly observed in the structures of other Ag sulphosalts and sulphides.

The use of non-harmonic parameters for Ag allowed a better description of the electron density related to Ag, which is usually difficult to refine in good ionic conductors. A careful analysis of the energy barriers between the Ag sites defines preferred ion-diffusion pathways within the crystal structure of stephanite. The diffusion of Ag ions occurs preferentially along the sites Ag1 and Ag2, giving rise to two-dimensional nets of Ag atoms in which the ion conduction probably takes place.

The effect of tunnel cations on tunnel size in α-MnO2 structured (hollandite, cryptomelane) materials has long been of interest, as the tunnel size effects catalytic and transport properties. Previous research on the tunnel size has focused on potassium cryptomelane (KxMn8O16). This paper uses synthetic control of silver content in AgxMn8O16 to investigate the effect that tunnel silver occupancy has on the lattice parameters. Materials with silver (x) content between 1.14 and 1.66 were synthesized, synchrotron diffraction and Rietveld Refinement was used to determine lattice parameters. The lattice parameters were found to contract as silver content increases (from 9.774 Å to 9.738 Å), in contrast to previous investigations of other tunnel cations.

The effects of Ag nanoparticles on microorganisms and the antimicrobial mechanism has recently been validated for different microbiological strains, as well as their cytotoxic effect in in vitro cellular models. In this work we report the synthesis of Ag nanoparticles using the extract of Eichhornia crassipes as reducing agent, and evaluated its antimicrobial activity with Escherichia coli. The morphology, size and inhibition properties of the nanoparticles as a function of the reduction time in the chemical synthesis were analyzed. The characterization was carried out by UV-Vis spectrophotometry and transmission electron microscopy. Nanoparticles with average diameters of 40 nm ± 10 nm were obtained and their antimicrobial activity with higher inhibition in Escherichia coli was recorded with the nanoparticle samples obtained at 120 min. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to various medical devices and antimicrobial control systems by modifying their concentration.

Chitosan is a polymeric compound with functional groups which enable surface binding to nanoparticles and antibacterial activity. The antimicrobial activity was studied using silver nanoparticles with varied concentrations of chitosan. The nanoparticles were synthesized through a simple and environmentally friendly method at room temperature. Spherical particles with average sizes between 2 and 6 nm were obtained and their crystallinity showed a face-centered cubic phase. The evidence of chitosan presence on the nanoparticle surface was confirmed by the characteristic diffraction peak of chitosan and by FTIR spectra where the bonding of amine group could be depicted. The chitosan-capped silver nanoparticles showed good antibacterial and antifungal activities with MIC values between 0.20 and 1.5 mg.mL-1 compared to those obtained from most of references (up to 6.25 mg.mL-1) on the selected gram-positive (Staphylococcus aureus, Enterococcus faecalis), gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa ) bacteria and fungi (Candida albicans, Cryptococcus neoformans).