Doped Ag Research Articles

The effect of Ag atoms diffusion into δ-phase CsPbI3-based memory device

In recent years, halide perovskite-based memory devices have attracted extensive research interest. Among them, CsPbI3-based memory devices are a kind of important research object. Perovskite-phase CsPbI3 (α-phase CsPbI3) is unstable at room temperature and will quickly transform into δ-phase CsPbI3, so the study of δ-phase CsPbI3-based memory devices become valuable. In this paper, using the Density Functional Theory (DFT), we find that when the interstitial doped Ag atom is closer to the I vacancy (VI) defect, the formation energy of the VI defect is reduced more, thus making it easier to promote the generation of VI defect, which leads to more favorable uniformity and stability for these CsPbI3-based memory devices. The reason lies in the fact that the doped Ag atom can serve as an effective recombination center, recombining the electrons around the doping Ag atom and the unpaired holes left around the VI. Our research uncovers the principle of the effect of Ag atoms on I vacancies formation in the CsPbI3 crystal for the first time, which provides a theoretical guidance for the fabrication of δ-phase CsPbI3 memory devices in the future.

NIR red luminescent doped Ag·(Y0.95Eu0.05)2O3 nanocomposite for 3-Chlorophenol sensor probe and anti-MDR bacterial application

Nanocomposite, Ag·(Y0.95Eu0.05)2O3 was characterized by XRD, SEM, EDS, TEM, FTIR and PL. Cubic morphology of Ag·(Y0.95Eu0.05)2O3 nanocomposite was observed with an average crystallite size of 43.78 nm. The materials showed excellent low temperature NIR red PL properties at 100 K, when excited by HeCd laser at 325 nm. The materials exhibited remarkable biological properties against MDR bacteria. The proposed sensor was assembled by depositing Ag·(Y0.95Eu0.05)2O3 nanocomposite on the flat part of a GCE to result a thin layer of nanocomposite and the sensor was applied to detect 3-CP in buffer solution in an electrochemical approach. To evaluate the sensor performances, the sensor calibration by plotting current versus concentration of 3-CP is executed, where currents data are distributed on a line from 0.1 nM to 0.01 mM defined as linear dynamic range (LDR) for 3-CP detection in buffer solution. The sensitivity of 3-CP sensor is calculated based on the slope of LDR considering the active surface area of GCE, which is equal to 23.5189 µAµM−1cm−2. The limit of detection (LOD) is calculated from the signal/noise ratio of 3, which is equal to 40.37 ± 2.02 pM. Besides this, the sensor parameters including reproducibility, response time and stability for long-time performance are evaluated in detail and found as reliable. Moreover, the real-time applicability of 3-CP sensor is tested by the electrochemical analysis of collected samples from environmental sources.

Photocatalytic, anti-bacterial performance and development of 2,4-diaminophenylhydrazine chemical sensor probe based on ternary doped Ag·SrSnO3 nanorods

Ag·SrSnO3 NRs is an excellent photocatalyst, kills both Gram positive and Gram negative bacteria. The 2,4-DAPHyd sensor fabricated by layered Ag·SrSnO3 NRs onto GCE shows high sensitivity (7.5854 μA μM−1 cm−2); LDR, 0.1 nM~0.01 mM & LOD, 96.13 ± 4.81 pM.

Structure-activity relationship of diameter controlled Ag@Cu nanoparticles in broad-spectrum antibacterial mechanism

Current outbreaks associated with drug-resistant clinical strains are demanding for the development of broad-spectrum antibacterial agents. The bactericidal materials should be eco-friendly, economical and effective to suppress bacterial growth. Thus, in this work, diameter controlled spherical Cucore-Agshell nanoparticles (Ag@CuNPs) with diameter ranging from 70 to 100 nm by one-step co-reduction approach were designed and synthesized. The Ag@CuNPs were homogenous, stable, and positively charged. The 70 nm Ag@CuNPs showed a consistent and regular Ag shielding. We observed the 100 nm Ag@CuNPs achieved symmetrical doped Ag clusters on the Cu core surface. We used Gram-positive and Gram-negative models strains to test the wide-spectrum antibacterial activity. The Ag@CuNPs showed detrimental microbial viability in a dose-dependent manner; however, 70 nm Ag@CuNPs were superior to those of 100 nm Ag@CuNPs. Initially, Ag@CuNPs attached and translocated the membrane surface resulting in bacterial eradication. Our analyses exhibited that antibacterial mechanism was not governed by the bacterial genre, nonetheless, by cell type, morphology, growing ability and the NPs uptake capability. The Ag@CuNPs were highly tolerated by human fibroblasts, mainly by the use of starch as glucosidic capper and stabilizer, suggesting optimal biocompatibility and activity. The Ag@CuNPs open up a novel platform to study the potential action of bimetallic nanoparticles and their molecular role for biomedical, clinical, hospital and industrial-chemical applications.

Tunability of negative permittivity and permeability of Ag/Zr0.9Ni0.1Oy nanocomposites with morphology

In this work, the effect of doping by Ag and stirring time on the structural, dielectrical and magnetical properties of Ag/Zr0.9Ni0.1Oy nanocomposite is considered. For all samples, the transmission electron microscopy (TEM) analyses show that doped Ag nanoparticles are dispersed randomly in the host dielectric. The permittivity and permeability behaviors of samples were investigated. Also, by changing the size of Ag, variation of permittivity and permeability changes are introduced. It was found that samples with 45, 47 and 50 wt% Ag exhibit the double negative (DNG) properties. Simultaneous negative permittivity and negative permeability were tunable in the Ag/Zr0.9Ni0.1Oy nanocomposites. We believe that the this work will be useful to all those interested in preparation of random nanocomposite DNG metamaterial.

Experimental and theoretical investigation of gigahertz nano-metamaterial

Chemical doping of Ag nanoparticles to dielectric medium becomes necessary to create an artificial structure which is useful for various applications, and gives rise to unique properties. Since structurally doped Ag nanoparticles is both of random and ordered, we have prepared Ag/Zr0.9Ni0.1Oy nanocomposites on the random status of this important class of materials. In doing so, effect of Ag content on the structure, electrical, magnetical and optical properties of Zr0.9Ni0.1Oy dielectric was investigated in detail. Characterization of chemically doped Ag also included. It was found that samples with 48 and 50 wt% Ag exhibit the double negative (DNG) properties. That is to say, simultaneous negative permittivity and negative permeability were realized in the Ag/Zr0.9Ni0.1Oy nanocomposites. We believe that the article will be useful to all those interested in DNG metamaterials and provides the present status of the subject.

Synthesis of Mn doping Ag–In–Zn–S nanoparticles and their photoluminescence properties

Mn doped Ag–In–Zn–S nanoparticles (Mn:AgInZnS) were successfully synthesized by using a practical hot-injection method. The as-prepared Mn:AgInZnS nanoparticles were triangular shape with average radius of 6(±0.5) nm, and the composition of doped Mn was about 7.29 by wt.%. Moreover, the Mn:AgInZnS nanoparticles demonstrated strong and stable photoluminescence emission at about 620nm, and the UV–vis absorption spectrum further revealed band gap absorption around 600nm. Furthermore, the photoluminescence lifetime of Mn:AgInZnS nanoparticles was about 1.38μs which indicated the tremendous potential applications in cell labelings, fluorescent imaging, solar cells and LEDs.

Magnetic Properties and Microstructure of Perpendicular ${\rm FePt}({\rm B}_{4}{\rm C-Ag})$ Granular Films

Multilayers [FePt(2.5 nm)/B4C(t nm)]4 (t = 0-1) and [FePt(2.5 nm)/(B4C)0.7Ag0.3(0.25 nm]4 were alternately deposited on a glass substrate and subsequently annealed using a rapid thermal process (RTP) at 800°C for 3 min. Thereafter, granular FePt(B4C) and FePt(B4C-Ag) films with perpendicular magnetization were formed. The immiscible B4C, Ag) elements were used as a segregant to isolate FePt grains and maintain c-axis alignment. B4C is an extremely covalent hard ceramic material with a high melting point, and it is used to separate FePt grains and prevent the formation of soft FeB during annealing. The minor doped Ag with high mobility was used to promote the ordering. The FePt grains were separated uniformly, and the average grains size was 14.7 nm in the (Fe0.48Pt0.52)90[(B4C)0.7Ag0.3)]10 film. Furthermore, the FePt grains were strong separated, and the grains size was reduced to 10.6 nm in annealed [FePt(1 nm)/(B4C)0.2Ag0.8(0.1 nm)]10 multilayer.

Electrospray ionization Fourier transform mass spectrometry of polycyclic aromatic hydrocarbons using silver(I)-mediated ionization

Here, a methodology employing doped Ag(I) salt as an in situ cationization reagent for efficient ionization of nonpolar molecules within a conventional electrospray ionization source is described. The effectiveness of Ag(I)-mediated ionization is demonstrated using ESI Fourier transform mass spectrometry for the rapid detection and identification of priority pollutant polyaromatic hydrocarbon (PAH) species. In contrast to earlier coordination ESI-MS reports employing silver salts, argentated species are not typically observed for PAH species. Instead, oxidation of the PAH occurs to produce only the [PAH]+· odd-electron molecular parent ion, simplifying spectral analysis. In addition, the method demonstrates linear quantitative performance. The Ag(I) reagent provides quantifiable PAHs (not ordinarily amenable to ESI-MS) from 64 ppb, and suggests the immediate potential for sampling and on-line monitoring of complex, real world, and otherwise intractable environmental samples. Finally, the high mass accuracy of ESI Fourier transform mass spectrometry further allows unequivocal identification of molecular formulas within PAH mixtures.Key words: electrospray ionization, nonpolar, hydrocarbons, polyaromatic, Fourier transform mass spectrometry.

Effects of Ag Doping on the Photoluminescence of ZnO Films Grown on Si Substrates

Silver (Ag) doped and undoped ZnO films were grown on Si (100) substrates by the sol-gel process. Photoluminescence (PL) of two kinds of samples as a function of the excitation intensity has been measured, and PL intensities have been fitted by a power law. It is found that Ag doping increases the intensity of free emission from ZnO and does not change the position and the full width at half-maximum of the free exciton emission. In PL spectra of two kinds of samples under various excitation powers, no visible emission bands related to the deep levels were observed. These results reveal that doped Ag in ZnO films only enhances emission efficiency from free exciton recombination, not giving rise to new emissions.

A Model Analysis of the Thermal Conductivity of Ag-doped Bi–Sr–Ca–Cu–O Superconducting Oxide

A phenomenological model to analyze the transport phenomena in inhomogeneous materials is proposed and applied to the measured thermal conductivity of Ag-doped Bi–Sr–Ca–Cu–O (Bi2212) superconducting oxide. Based on the model, the effective ratios of the doped Ag amount in the grain boundary to that inside of the grain are determined to be 0.75:1.0 for a Bi2212+15 wt%Ag specimen and 0.85:1.0 for a Bi2212+10 wt%Ag specimen. The model analyses indicate that doped Ag particles preferentially occupy the grain boundaries, contributing to the formation of the linked Ag heat path in the oxides.

Electrocatalytic cells for chemical reaction

Solid oxide fuel cell technology has been successfully applied to the partial oxidation of methane to produce ethane and ethylene and to the oxydehydrogenation of ethane to produce ethylene. One electrocatalytic cell consists of a solid electrolyte (yttria-stabilized zirconia) coated on either side with a conductive metal to form electrodes. Air is passed over one side of the cell where it reacts with the cathode to form oxygen anions. The oxygen anions are transported through the zirconia to the anode where they oxidize the substrate. The cathode and anode are connected by an external circuit so that a current is generated. The choice of electrocatalyst on the anode affects the product selectivity. In the partial oxidation of methane, high selectivities to C 2+ have been obtained using doped Ag or Au anodes. At 800°C under conditions of low conversion, the selectivity to C 2+ was as high as 86% for a AgPb anode. In all cases selectivity decreases with increasing conversion. The highest yield was obtained with the AgPb anode at 850°C. Co-feed experiments using CH 4C 2H 4 mixtures shed light on the limit of the methane coupling yield. An advanced cell concept incorporating a second, conducting phase along with an oxygen conducting electrolyte to produce an internal short circuit will be described. High oxygen fluxes (current densities) have been measured that may permit these materials to be used as oxygen separating membranes in chemical reactors.

Effect of Heteroatomic d10 Interactions on the Optical Properties of Cu+ Doped Ag+-ß″-Alumina

ABSTRACTThe optical properties of Cu+ doped Ag+-ß″-alumina are strongly affected by interactions between the d10 closed shell Cu+ and Ag+ ions. These effects can be distinguished from Cu+-Cu+ interactions previously observed in ß″-alumina, and produce a strong red emission upon ultraviolet excitation.