Au和Ni掺杂n型硅材料的制备及其热敏特性

为了制备高B低阻的硅单晶热敏材料,采用开管涂源的方法,对n型单晶硅进行Au、Ni两种过渡族金属的双重高温掺杂,得到对温度敏感的补偿硅材料,并对其进行测试和分析.掺杂后得到的硅单晶热敏材料,其导电类型仍为n型,且电阻率较低,为欠补偿,测试结果表明其常温电阻率ρ25=64～416Ω·cm,温度敏感系数(B值)在5300K左右;根据半导体中深能级杂质理论推导计算得到的材料的B值,与实验值基本一致.     

纳米Au团簇在氧化钛修饰的介孔分子筛MCM-41中的组装

以钛酸丁酯为ＴｉＯ_２前驱体,使ＴｉＯ_２均匀分散于纯硅介孔分子筛ＭＣＭ－４１的介孔孔道内表面,利用ＴｉＯ_２光学性质将ＡｕＣｌ－４还原为Ａｕ（０）并组装于氧化钛修饰的ＭＣＭ－４１孔道中．对所合成的Ａｕ负载的氧化钛修饰的ＭＣＭ－４１进行了ＸＲＤ,ＸＰＳ,Ｎ_２吸附－脱附曲线,及固体ＵＶ－Ｖｉｓ漫反射等多种结构表征．由ＸＰＳ谱和固体ＵＶ－Ｖｉｓ漫反射吸收光谱的ｐｌａｓｍｏｎ吸收峰证明Ａｕ团簇呈现０价的金属状态．     

Lattice parameter and expected density of Au nano-structures sputtered on glass

Gold nano-structures (clusters and layers) were sputtered on the glass substrate. Lattice parameter was determined by X-ray diffraction. Density of Au nano-structures was calculated depending on structures size. Density of gold structures increases from the value of 13.6 · 10³ to 19.3 · 10³ kg m^− 3. Free volume fraction of structures decreases from the value of 48 to 26%.     

Composites of Bacterial Cellulose and Small Molecule‐Decorated Gold Nanoparticles for Treating Gram‐Negative Bacteria‐Infected Wounds

Bacterial infections, especially multidrug‐resistant bacterial infections, are an increasingly serious problem in the field of wound healing. Herein, bacterial cellulose (BC) decorated by 4,6‐diamino‐2‐pyrimidinethiol (DAPT)‐modified gold nanoparticles (Au‐DAPT NPs) is presented as a dressing (BC‐Au‐DAPT nanocomposites) for treating bacterially infected wounds. BC‐Au‐DAPT nanocomposites have better efficacy (measured in terms of reduced minimum inhibition concentration) than most of the antibiotics (cefazolin/sulfamethoxazole) against Gram‐negative bacteria, while maintaining excellent physicochemical properties including water uptake capability, mechanical strain, and biocompatibility. On Escherichia coli‐ or Pseudomonas aeruginosa‐infected full‐thickness skin wounds on rats, the BC‐Au‐DAPT nanocomposites inhibit bacterial growth and promote wound repair. Thus, the BC‐Au‐DAPT nanocomposite system is a promising platform for treating superbug‐infected wounds.     

Deformation of thin foil of fcc and bcc metals containing pre-introduced He bubbles

Thin foil of fcc and bcc metals subjected to tensile deformation has been found to exhibit an anomalously high density of small vacancy clusters, probably in the absence of dislocations. Deformation of fcc Au and bcc Fe containing pre-introduced He bubbles is carried out, at strain rates ranging from 10⁻³ to 10⁵ s⁻¹ to a 10²% strain at −180 and 25 °C. Microstructures in the deformed regions are examined by transmission electron microscopy. Rows of bubbles are formed due to extreme elongation of bubbles under stress and its subsequent division into smaller pieces in response to vacancy diffusion around the bubble surfaces. The bubble rows are parallel to the low-index crystallographic directions, 001, 011, and 012 for Au and 011 and 001 for Fe, which can be resolved into ‘slip directions’. The results indicate that displacement of atoms in these thin-foil specimens during tensile deformation progresses while conforming to the nature of the crystal, even in the absence of dislocations.     

金纳米粒子的结晶化处理

采用类似蛋白质结晶的方法对对巯基苯甲酸包覆的金纳米粒子胶体进行了处理,初步探索了有机溶剂浓度和pH值对形成金纳米粒子超晶格的影响,实验发现甲醇浓度对产物的组成、形貌和结构具有显著影响,甲醇浓度一定时,通过调节pH值,金纳米粒子可以结晶成具有一定几何形态的超晶格,并对相关的形成机制进行了论述。     

Preparation of Z-scheme Au-Ag2S/Bi2O3 composite by selective deposition method and its improved photocatalytic degradation and reduction activity

In this work, Z-scheme Ag₂S/Bi₂O₃ composites were fabricated through the precipitation of Ag₂S nanoplates on the surface of Bi₂O₃ microrods. Consequently, Au nanoparticles were selectively deposited on the Ag₂S nanoplates surface to obtain.Au-Ag₂S/Bi₂O₃ composites using near-infrared light photodeposition method. The characterization results indicate that the Ag₂S nanoplates were uniformly anchored on Bi₂O₃ surface, and Au nanoparticles were highly dispersed on the surface of Ag₂S nanoplate instead of Bi₂O₃. Acid orange 7 (AO7), Rhodamine B (RhB) and Cr(VI) were chosen as model reactant for the evaluation of photocatalytic degradation and reduction activity of the products under simulated sunlight irradiation. After the decoration of Ag₂S nanoplates, the photocatalytic activity of Ag₂S/Bi₂O₃ is much higher than that of bare Bi₂O₃, and the optimal catalytic efficiency is achieved by 12 %Ag₂S/Bi₂O₃ sample. More importantly, the photocatalytic activity of 12 %Ag₂S/Bi₂O₃ sample can be further enhanced by the selective decoration Au nanoparticles on the Ag₂S nanoplates. Among the ternary composites, 2Au-12 %Ag₂S/Bi₂O₃ sample with the Au content of 2% exhibits highest catalytic efficiency for 60 min (AO7: 96%; RhB: 56%; Cr(VI): 65%). The possible mechanism for the improvement of the photocatalytic activity of Bi₂O₃ by Ag₂S and Au decoration was proposed.     

Improved adhesion of Au thin films to SiOx/Si substrates by dendrimer mediation

Quantitative evidence of significantly improved interfacial adhesion between Au films and SiO_x/Si substrates induced by an organic dendrimer monolayer was presented. For dendrimer-mediated Au films, nanoscratch tests revealed a critical load that was two times higher than that for films without dendrimer mediation. Atomic force microscopy (AFM) examination of nanoindents revealed much constrained lateral flow of metals in the dendrimer-mediated Au films during nanoindentation, indicating enhanced adhesion due to the presence of the dendrimer layer.     

‘Fairy Chimney’‐Shaped Tandem Metamaterials as Double Resonance SERS Substrates

A highly tunable design for obtaining double resonance substrates to be used in surface‐enhanced Raman spectroscopy is proposed. Tandem truncated nanocones composed of Au‐SiO₂‐Au layers are designed, simulated and fabricated to obtain resonances at laser excitation and Stokes frequencies. Surface‐enhanced Raman scattering experiments are conducted to compare the enhancements obtained from double resonance substrates to those obtained from single resonance gold truncated nanocones. The best enhancement factor obtained using the new design is 3.86 × 10⁷. The resultant tandem structures are named after “Fairy Chimneys” rock formation in Cappadocia, Turkey.     

Gold nanoparticles by Terminalia bellirica aqueous extract – a rapid green method

Synthesis of metal nanoparticles (NPs) using plant extracts as reducing agents is of great interest due to its ease and environmental friendly process. Reports show biogenic green synthesis reaction times in forming gold metal nanoparticles (Au NPs) varying from minutes to several hours. In this article, an instantaneous (less than 10?s) method for the green synthesis of gold NPs using aqueous extract of Terminalia bellirica as a reducing and stabilising agent has been reported. Formation of Au NPs was instantaneous and confirmed by UV-Vis spectroscopy where surface plasmon resonance band centred at 530?nm. Formation of anisotropic Au NPs was evidenced from transmission electron microscope studies. High levels of polyphenols in T. bellirica were responsible for the rapid reduction and stabilisation. The Au NPs did not display toxicity when tested by the brine shrimp (Artemia salina) assay.     

Au(Ru)-SiO2纳米-微米复合粒子的制备及精细结构研究

在制备出高性能的Au(Ru)-SiO2纳米-微米复合粒子的基础上，使用高分辨透射电镜、电子探针和X-射线衍射等现代手段，研究了该复合粒子的精细结构。研究结果表明：所制备的纳米-微米复合粒子在结构上呈现类似天体星云式的多层次结构，可区分为三级，其中一级结构是在微米尺度上，该层次上的SiO2微粒是整个复合粒子的承载骨架，其粒度均匀，分散性好，这在一定程度上大大降低了其所包含的功能金、钌纳米粒子的团聚问题；二级结构是在纳米尺度上，观察发现，金、钌纳米粒子相对均匀地镶嵌在第一结构层次的SiO2微粒中，它们是整个材料的性能载体，对材料性能起决定作用，研究指出进一步适度降低第一层次的SiO2微粒的粒径有望进一步降低甚至消除其中金、钌纳米粒子间的团聚；三级结构为金、钌纳米晶粒的高分辨晶格像，表明纳米晶表面原子点阵存在畸变。研究还指出，在该纳米-微米复合粒子中，金属金、钌的纳米粒子是以机械混合形式存在，不形成合金，也不形成固溶体。     

Plasmonic-enhanced electrochemical detection of volatile biomarkers with gold functionalized TiO2 nanotube arrays

Titania nanotubular arrays(TNA) synthesized via electrochemical anodization is a stable and versatile material, widely studied for photocatalytic and sensing applications, whereas nano-sized gold particles are a known plasmonic material. Semiconductor–metal nanocomposites in isolated, embedded, or encapsulated form, when irradiated with proper light frequency can exhibit localized surface plasmon resonance(LSPR) effect. This effect can result in improved light adsorption and electrical properties of a material. In this study, we report the enhanced visible light photo-response of LSPR induced volatile organic biomarker vapor sensing at room temperature using a Au-embedded TNA electrochemical sensor.Two mechanisms are proposed. One based on classical physics(band theory), which explains operation under non-irradiated conditions. The second mechanism is based on the coupling of classical and quantum physics(molecular orbitals), and explains sensor operation under irradiated conditions.     

直流磁控溅射法制备金钆多层膜

本文介绍了直流磁控溅射方法制备Au／Gd多层膜，探索了多层膜的制备工艺参数，利用X射线衍射表征了多层膜的界面结构及混和膜的晶型结构，原子力显微镜观察了膜的表面形貌和粗糙度。成功地制备了膜层厚度控制精确、界面清晰和表面光洁的Au／Gd多层膜。     

Highly efficient avalanche multiphoton luminescence from coupled Au nanowires in the visible region

We report highly efficient avalanche multiphoton luminescence(MPL)from ordered-arrayed gold nanowires(NWs).The time-average excitation intensity I_(exc) is as low as 5.0-9.1 kW/cm~2.The intensity of avalanche MPL I_(MPL) is about 10~4 times larger than that of three-photon luminescence,the slope ■logI_(MPL)/■logI_(exc) of avalanche MPL reaches as high as 18.3 and the corresponding polarization dependence of I_(MPL) has a form of cos~(50)■_p.The emission dynamics of avalanche MPL and three-photon luminesc...     

Annealing structured Au nanoparticles enhanced light emission from CdSe quantum dots

Enhancement of the light emission of CdSe quantum dots was observed by coupling through localized surface plasmons from Au nanoparticles. The enhancement was found to be relative to the shapes and sizes of Au nanoparticles. Au nanoparticles of different sizes were synthesized by a citrate-seeded method. By varying the annealing temperature, worm-like Au nanoparticles of different aspect ratios from 1 to 5 were obtained. Samples of the CdSe coupled with Au with an aspect ratio of 2 and annealed at 500 °C exhibited the best photoluminescence emission efficiency. Furthermore, a stronger photoluminescence enhancement was observed with increasing the size of Au nanoparticles. It was also found that when the localized surface plasmons resonance absorption wavelength of Au nanopartiles was just a little smaller than the emission peak of CdSe, the CdSe quantum dots exhibited the strongest photoluminescence intensity, with an enhancement of 6 times.     

Microtubule-based gold nanowires and nanowire arrays

Biological structures are attractive as templates to form nanoscale architectures for electronics because of their dimensions and the ability to interact with inorganic materials. In this study, we report the fabrication and electrical properties of microtubule (MT)-templated Au nanowires, and methods for assembling Au nanowire arrays based on these templates. The adsorption of MTs on silicon substrates is an effective means for preserving the conformation of the MT and provides a convenient platform for electrical measurements. To improve the metallization of MTs, a photochemical route for gold reduction is adapted, which leads to continuous coverage. The conductivity values measured on micrometer-long nanowires are similar to those reported for other biotemplated gold nanowires. A protocol for fabricating arrays of MT-templated gold nanowires is demonstrated.     

The Noise and Energy Resolution of the Ti/Au Bilayer X-ray TES Calorimeter with an Au Absorber

We fabricated the TES microcalorimeter with TES(Ti/Au) and gold absorber, and obtained FWHM energy resolution of 4.8±0.3 eV at 5.9 keV. The baseline resolution, i.e. the resolution determined by noise, was 4.1±0.1 eV. From the noise spectra we found that the square of the baseline resolution could be approximately decomposed into contributions of three noise components. They are estimated to be (2.5 eV)² (the intrinsic noise), (1.5 eV)² (the readout noise), and (3.0 eV)² (so-called excess noise). There is additional broadening of (2.5 eV)² from the baseline resolution. The excess noise is the largest limiting factor of the energy resolution of the device.      

沉积在硅油表面上Au薄膜的电学性能及成膜机理

采用硅油作基底 ,沉积出具有网状特征结构的逾渗Au薄膜 ,用四引线方法原位测量Au薄膜的电学性能 ,测得其电阻随沉积时间以及凝聚时间的变化规律 ,较好地解释了此类薄膜的生长机制。对Au薄膜R I特性的测量结果表明 :生长在液体基底表面Au薄膜的局域隧道电流和跳跃电导效应比一般薄膜更为强烈 ,其功率谱指数w趋于零 ,该值远小于普通逾渗薄膜系统的相应值     

Enhanced thermal stability of laccase immobilized on monolayer-modified nanoporous Au

Nanoporous Au was fabricated by the dealloying of Au-Ag alloy in nitric acid, and was modified with a self-assembled monolayer (SAM) of 4-aminothiophenol, for the enhancement of high-temperature activity of immobilized laccase. Immobilized laccase exhibited much higher activity than that of free laccase at > 45 °C. SAM surface modification greatly improved the thermal stability and reusability of immobilized laccase. For example, little degradation in laccase activity when immobilized on SAM-modified nanoporous Au was observed after 2 h incubation at 50 °C. This suggested the nanoporous structure and SAM synergistically prevented the conformational change of laccase, and resulted in the enhancement of high-temperature activity.