Spectroscopic measurements in the range of 10 kHz to MHz at different temperatures are reported for Au/CIMgPc/Au thin film sandwich devices. The ac conductivity is found to vary with the angular frequency ω as ωn where the index n≈ 1at high frequencies indicating the predominance of a hopping conduction mechanism in this material at low temperatures and high excitation frequencies. The variation of activation energy is studied as a function of temperature and frequency. The capacitance data are analysed within the framework of the Goswami model [10].      

In this paper, Au nanoparticles are synthesized by solution method. The effect of these nanoparticles on the Bi1.6Pb0.4Sr2Ca2Cu3Oysuperconductor properties has been investigated. The critical current density, activation energy and room temperature resistivity were measured by the standard four-probe method. The microstructure and morphology of samples have been studied by X-ray diffraction, Scanning Electron Microscope and Energy Dispersive X-ray. The results of X-ray diffraction patterns show that the low amount of Au and annealing time of 72h enhance the fraction of Bi -2223 phase. Also crystallography studies showed that the gold has entered the superconductor's structure and the results were in consistency with superconductor's SEM images.

Direct conversion of Solar energy to electrical energy using nanostructured organic/inorganic hybrid semiconductors is one of the best solutions for today’s energy crisis. Researchers are turning their attention to the incorporation of metal or transition metal oxide nanoparticles (NPs) into the active layer of polymer solar cells (PSCs) to increase the power conversion efficiency. The design approaches for the incorporation of metal NPs such as gold (Au) are based on localized plasmonic resonance effect (LSPR) which can be used to enhance the optical absorption in photovoltaic devices. Meanwhile, the transition metal oxide NPs such as Cuprous oxide (CuO) NPs in the active layer play a key role as light-harvesting centers, charge particle hopping centers, and surface morphology developers enabling a considerable reduction in the physical thickness of photovoltaic absorber layers. In this study, Au and CuO NPs are incorporated into poly(3-hexylthiophene) (P3HT)/ [6:6]-phenyl-C61-butyric acid (PCBM) active layer to enhance the power conversion efficiency (PCE) of the PSCs. The influence of the Au and CuO NPs in the P3HT/PCBM was investigated using UV–Vis spectroscopy, scanning electron microscopy, and atomic force microscopy. Electrical characteristics of the devices were analyzed from J–V characteristics and external quantum efficiency measurement to observe the performance of the P3HT: PCBM PSCs. The addition of Au and CuO NPs increased the power conversion efficiency by 48.7% compared to the reference cell. The short circuit current(Jsc) of the optimum cell was measured at 7.218 mA/cm2. Also, the external quantum efficiency(EQE) increased from 45% to 68.5%, showing 52.2% enhancement.

In this work, we have developed a novel visual Hg2+ sensor in aqueous solution using unmodified Au@Ag core-shell nanoparticles at room temperature, based on a redox reaction between Ag-shell and Hg2+. The prepared Au@Ag core-shell nanoparticles exhibited good monodispersity.In the presence of Hg2+, Hg2+ was reduced into Hg (0) by Ag-shell, and deposited on the surface of Aucore to form Au-Hg alloys and caused nanoparticles aggregation, leading to the color changes of the solution from yellow to purplish red, and the surface plasmon resonance spectra of Au@Ag core-shell nanoparticles red shift. Under the optimal conditions, the visual sensor could selectively detect Hg2+ as low as 0.4 mM with the naked eye and 5.0 nM by UV–vis spectra analysis methods. The designed sensor had several advantages: (1) the nanoparticles surface need not be functionalized. (2) The color change of the solution was in 2 s and could easily be observed with naked eyes. The visual sensor had been applied to detection of Hg2+ in tap and lake water, which obtained satisfied result.

This study uses economical and ecologically friendly techniques to create gold nanoparticles (Au-NPs) and copper nan]oparticles (Cu-NPs) utilizing distilled water (DW) solution and the liquid pulse laser ablation (PLAL) technique with a wavelength of 1064 nm and varying laser intensities. Using X-ray diffraction (XRD) and absorption spectrometry, the characteristics of Au-NPs and Cu NPs as well as Au-CuNPs were investigated. The results indicated that a crystal structure for gold (Fcc) had formed.The appearance of the surface plasmon resonance (SPR) peak at 523 nm in the UV visible spectrum in the Uv-Vis data demonstrated the creation of Au NPs. Cu NPs and Au NPs nanoparticles (Au-CuNPs) have antibacterial properties against E. coli and Staph aureus. This is because the high surface-to-volume ratio offers provides a more effective means of enhancing bacterial activity as measured by the area of inhibition. provides a more effective means of enhancing bacterial activity as measured by the area of inhibition. There are numerous opportunities to investigate nanoparticles' theranostic role in molecular imaging thanks to recent developments in nanotechnology and nanomaterials. In molecular imaging, gold nanoparticles have been widely used as contrast agents and drug delivery systems. This is because of the exceptional qualities of gold nanoparticles, such as their high chemical stability, facile bioconjugation with different molecules, and outstanding biocompatibility with human cells. Gold nanoparticles can be created using different processes including conventional chemical synthesis, radiation technologies, electrochemical, bio-synthesizing and pulsed laser ablation in liquid (PLAL)

In this research, we try to improve the performance of ultraviolet (UV) photodetector based on ZnO nanorods through decoration with Au nanoparticles. One-dimensional ZnO nanorods were grown on the quartz substrates by the vapor phase transport (VPT) method. Then, Au nanoparticles by depositing a thin nanometric Au layer with thicknesses 3, 6, 9, and 12 nm via sputtering technique and a heating process were coated on the ZnO nanorods. The morphology and structure of the samples were characterized by using a Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD). The results showed formation of rather aligned ZnO nanorods with wurtzite hexagonal crystalline structure and preferred orientation along the c-axis which are coated with Au nanoparticles. The obtained data from measuring ultraviolet photoresponse shows that the decorated sample with 9 nm thick Au film possesses a higher on/off ratio (6. 5), responsivity (568 ± 33 mA/W), and faster rise and decay times. In addition, with presence of Au nanoparticles, responsivity in the visible region (λ= 520 nm) increased from 6 ±0. 5 mA/W to 19±1 mA/W. This improved detecting behavior results from Localized Surface Plasmons (LSPs) of the Au nanoparticles and the formation of localized Schottky barriers between Au nanoparticles and ZnO.

There has been substantial recent interest in studying monolayer-protected gold clusters (MPCs) owing to their diverse applications. The present work is an electrochemical study of novel gold nanoparticles covered with a monolayer of mercapto-dodecanol ended chloro-dicyano-quinone (HS-C12O-CDQ), which was adsorbed on the electrode (CDQ-MPCs film). Our findings reveal a redox behavior for CDQ-MPCs film similar to the solution electrochemistry of dichloro-dicyano-quinone. Furthermore, a diffusion-like mechanism was found for electron transfer, which may have occurred due to proton diffusion towards or outwards the electrode through the film casted. Chronoamperometry confirmed diffusion behavior of the ET process. Finally, EIS was used to find the rate constant of ET process for the redox reaction that occurred and the contribution of MPCs in total interfacial capacitance.

Nano sized particles of gold and silver were produced in aqueous solution as well as in calcium alginate gel beads by simple addition of amino polycarboxylic acids (APCAs) and alginate. It is shown that the composite of alginate and APCAs served as a reductant and stabilizer.The influence of experimental parameters on the formation of nanoparticles was investigated via UV–visible spectroscopy, X-ray diffraction, transmission electron microscopy, and selected area electron diffraction analyses.Further, using sorption experiments it has been demonstrated that the loading of gold nanoparticles on calcium alginate beads is much more as compared to that of Ag nanoparticles. The as-prepared metal sols and solid-phase biopolymer-based nanoparticles show excellent stability.