Electrical Characterization of Individual Cesium Lead Halide Perovskite Nanowires Using Conductive AFM

Perovskite nanostructures have attracted much attention in recent years due to their suitability for a variety of applications such as photovoltaics, light-emitting diodes (LEDs), nanometer-size lasing, and more. These uses rely on the conductive properties of these nanostructures. However, electrical characterization of individual, thin perovskite nanowires has not yet been reported. Here, conductive atomic force microscopy characterization of individual cesium lead halide nanowires is presented. Clear differences are observed in the conductivity of nanowires containing only bromide and nanowires containing a mixture of bromide and iodide. The differences are attributed to a higher density of crystalline defects, deeper trap states, and higher inherent conductivity for nanowires with mixed bromide–iodide content.     

Effect of inorganic constituents on chemical oxygen demand—I. Bromides are unneutralizable by mercuric sulfate complexation

Chemical oxygen demand (COD) assays are widely used for the estimation of the organic carbon content of water and wastewater. The procedure is subject to interference by free halogen ions, the oxidation of which creates artificially high COD values. As part of an investigation of the interferences involved in the COD determination of chemical industries wastewaters, we found that mercuric sulfate complexation, the standard procedure for neutralizing the halogen effects, is suitable for chlorides but is not applicable to bromides. This observation is true both in the presence or absence of chloride or ammonia. Care should therefore be exercised in the interpretation of COD data for bromide-containing samples.     

One-pot fabrication and magnetic studies of Mn-doped TiO(2) nanocrystals with an encapsulating carbon layer

Mn-doped TiO(2) nanocrystals encapsulated in a carbon layer (Ti(1-x)Mn(x)O(2)@C) were synthesized by the one-pot RAPET (reaction under autogenic pressure at elevated temperature) technique. Manganese was doped into the body-centered tetragonal TiO(2) anatase phase to give a Mn:Ti atomic ratio of 1%, 5% and 10%. The surface modification by carbon was achieved in order to make the cubic/tetragonal nanocrystals non-toxic and biocompatible. Electron paramagnetic resonance (EPR) studies revealed a broad resonance (centered at g = 1.9977 due to the interacting spins in the oxide matrix) with increased dopant concentration and the resonance due to carbon. Manganese is mainly present as +II or +III oxidation states. The magnetic behavior was found to be very dependent on the manganese concentration with a ferromagnetic behavior of the 1% doped sample due to the coupling between carriers and manganese spins. A predominant paramagnetic behavior was observed for the higher Mn-doped samples. This study opens up a new dimension for the carbon encapsulation of room-temperature ferromagnetic diluted magnetic semiconductor (DMS) nanomaterials.     

Design methodology of refractive index engineering by implantation of high-energy particles in electro-optic materials

Slab waveguides were constructed in K(1-x)Li(x)Ta(1-y)Nb(y)O(3) crystals by the implantation of (12)C(+4) ions at 30 MeV and (16)O(+5) ions at 30 and 40 MeV. The waveguides were characterized by a prism coupler setup. A refractive index drop of 10.9% was observed in a layer formed by the implantation of (16)O(+5) ions at 30 MeV. The carbon-implanted waveguides were found to be thermally stable after annealing at 450 degrees C. A semiempirical formula for predicting the change in the refractive index given the parameters of the implantation process was developed. It is argued that the combination of the basic implantation process with the semiempirical formula can be developed to become a generic method for constructing complex electro-optic circuits with a wave-guided architecture.     

Inhibition of HSV‐1 Attachment,Entry, and Cell‐to‐Cell Spread by Functionalized Multivalent Gold Nanoparticles

The use of modified nanoparticles in interactions with biological targets is attracting rapidly increasing attention. In this Full Paper, the application of gold nanoparticles capped with mercaptoethanesulfonate (Au‐MES NPs) as effective inhibitors of Herpes simplex virus type 1 infection based on their ability to mimic cell‐surface‐receptor heparan sulfate is described. Mechanistic studies reveal that Au‐MES NPs interfere with viral attachment, entry, and cell‐to‐cell spread, thereby preventing subsequent viral infection in a multimodal manner. The ligand multiplicity achieved with carrier nanoparticles is crucial in generating polyvalent interactions with the virus at high specificity, strength, and efficiency. Such multivalent‐nanoparticle‐mediated inhibition is a promising approach for alternative antiviral therapy.     

Fabrication of (La1−x Gd x )2/3Sr1/3MnO3 Manganite Perovskite Nanorods by Sonication-Assisted Coprecipation

(La_1?x Gd _x )_2/3Sr_1/3MnO₃ manganite perovskite nanorods were synthesized by sonication-assisted coprecipitation. Lower sintering temperatures were required for all the samples to crystallize. The fully crystallize samples of (La_0.5Gd_0.5)_2/3Sr_1/3MnO₃ and (La_0.4Gd_0.6)_2/3Sr_1/3MnO₃ show the formation of nanorods upon their synthesis with an average length and width of 160 nm and 20 nm, respectively. The structural, electrical, and magnetic transport properties were investigated.     

Fabrication,Characterization, and Printing of Conductive Ink Based on Multi Core–Shell Nanoparticles Synthesized by RAPET

In the current research, conductive patterns are deposited on different substrates by direct inkjet printing of conductive inks based on metal@carbon and bimetal@carbon core–shell nanoparticles synthesized by the RAPET (reaction under autogenic pressure at elevated temperatures) technique. Various co‐solvents and additives are examined for production of stable conductive ink. The morphology of the deposited layers is characterized by optical and scanning electron microscopy measurements. The stability of the prepared inks is examined by dynamic light scattering measurements. The electrical resistivity is measured by a four‐point probe system and calculated using the geometric dimensions. The results obtained are very promising and indicate that the conductivity of the deposited layers is close to that of bulk metals and higher than most results published so far. Moreover, the importance and advantages of the protective carbon layer that prevents metal oxidation is demonstrated.     

微波辅助polyol法制备纳米金属镍及磁性研究

采用微波辅助polyol法成功地制备了直径范围在5～10nm、100～180nm的单分散Ni球,对其磁性进行了测量分析.用XRD和EDAX,接着用TEM和MFM分别对制备的样品进行测试,并用VSM和SQUID进一步讨论了铁磁/反铁磁的界面耦合效应.XRD显示该样品是面心立方结构,EDAX数据表明制备过程中镍球被轻微氧化,MFM和TEM观察结果显示样品金属镍是比较理想的球型,VSM测试结果表明Ni纳米球具有典型的铁磁性.