交流电沉积实现微纳器件定向连接研究

使用交流电化学方法定向制备了预制微电极之间的电连接。通过调节交流电压与偏置直流电压幅值可以控制电连接的生长方向。如果施加的交流电压幅值高于生成电连接的电压阈值,并且该值恒定时,频率越小,浓度越大,电连接晶体越粗壮;而当电解液浓度与频率恒定时,电压幅值变化对形貌影响较小。有限元仿真模拟进一步说明：当施加的交流电压高于阈值时,电极处于交流电渗流上游。电极扩散层厚度增加将诱导电极之间电连接晶体的生长。在交流电压上叠加直流偏置电压时,电连接晶体从偏置电压相对较负的一端向另一端生长。伏安特性测试结果表明：该连接具有优异的接触特性。     

表面增强拉曼光谱在环境分析中的研究进展

表面增强拉曼散射(SERS)效应是一种异常的表面光学效应,其增强因子最大可达到1014～1015.环境污染导致人类生存环境受到严重影响.某些污染物,比如持久性污染物,在环境介质中含量低,毒性大,很少能够直接检测出来.因此必须采用更灵敏的方法和技术.由于SERS效应的高灵敏性,SELLS技术有望成为超灵敏分析环境污染物的一种工具.该文综述了表面增强拉曼光谱在环境污染物检测中的研究进展,并提出SERS传感器将是很重要的发展方向.     

金纳米颗粒制备及其光学特性研究

采用晶种生长法通过改变晶种对生长溶液的体积比例、引入离子合成了棒状和星形金纳米颗粒.首先用NaBH4作为还原剂制得小粒径球形金纳米颗粒作为晶种溶液,生长溶液中引入AgNO3为辅助试剂、溴化十六烷三甲基铵(CTAB)为表面活性剂来引导合成形貌不同的颗粒.对制备的球状、棒状和星状金纳米颗粒进行了紫外-可见光谱测试和表面增强...     

一种新型包埋染料的核壳纳米颗粒表面增强共振拉曼探针的研制及其在免疫分析中的应用

应用于生物分析的纳米探针主要包括:等离子体共振颗粒探针,量子点、荧光探针和拉曼探针等等.拉曼探针跟其它纳米颗粒探针相比,其重要的优点是它能提供丰富的分子结构信息,从而很大程度上避免了光谱重叠,有可能研制出各种不同的拉曼探针.特别值得注意的是,基于表面增强与共振增强相结合的纳米拉曼探针,能超灵敏地、高特异性地检测生物分子.该文采用了一种新型的合成方法,成功地制备了以纳米金为核,二氧化硅为外壳,且其中包埋有染料的金/二氧化硅核壳纳米颗粒,并把它作为一种表面增强共振拉曼(SERRS)探针用于免疫分析.     

Au纳米粒子修饰纳米片状结构衬底的SERS研究

通过电化学共沉积和化学脱合金处理在金属W片上制备了纳米片状基底,将Au纳米粒子通过等离子溅射到纳米片状基底上得到表面增强拉曼散射(SERS)衬底。采用扫描电子显微镜(FE-SEM)、能谱仪(EDX)对复合纳米衬底进行表征,罗丹明6G作为探测分子对SERS衬底的拉曼表面增强效果进行检测。通过实验发现:三维空间结构的纳米片状结构具有拉曼表面增强效应,溅射Au纳米颗粒得到的Au纳米片衬底信号增强效果显著。     

多层纳米银／壳聚糖膜用于芘的表面增强拉曼测定

多环芳烃类物质的高疏水性质使得其在金属表面吸附能力差,从而拉曼增强信号弱。该文针对此问题,制备了以壳聚糖为骨架,纳米银颗粒为热点的多层纳米银／壳聚糖复合膜表面拉曼增强基底,成功用于芘的表面增强拉曼检测。由于壳聚糖本身的富集作用,目标分子被吸附、富集于银纳米颗粒形成拉曼热点,可检测0．01μmol／L的芘。     

液相自组装在表面增强拉曼散射生物传感器中的研究进展

研究发现在不混溶两相界面自组装的纳米粒子可以用于构建液相表面增强拉曼散射（SERS）基底,与传统的固相SERS生物传感器相比,基于此技术发展起来的液相SERS生物传感器具有界面无损、组装快速、自愈合、可以进行原位检测等优势。由此衍生出了一系列在液相自组装SERS活性材料构建生物传感器的方法,该文重点讨论了将液相自组装SERS技术用于对一类重要的疾病标志物microRNAs(miRNAs)的检测中,以扩展基于液相自组装界面作为SERS基底的生物传感器更广阔的应用。     

Nanopillar-forest based surface-enhanced Raman scattering substrates

In this work,nanopillar-forest based surface-enhanced Raman scattering substrates were fabricated using a novel approach.The key technique of the approach is taking advantage of convexes on Poly-Si surfaces as support structures in sidewall technology.The tip-diameters of the fabricated nanopillars are from 5 to 10 nm,heights are of several microns,and density of the nanopillar-based forests is around 20/μm2.In these nanopillar forests,there are plenty of nanoscale gaps.When covered with a thin layer of noble metal,the nanopillar forests exhibit a high SERS-active capability.Primary measurement results demonstrate that the nanopillar-forest based SERS substrates have an enhancement factor of an order of 4.62×106.It is expected that such SERS substrates may have applications in biological monitoring and chemical detection.     

Preparation of PCLT/P(VDF-TrFE) pyroelectric sensor based on plastic film substrate

Nanosized lead titanate doped with calcium and lanthanum (PCLT) powder obtained by the sol–gel method was homogeneously mixed with vinylidene fluoride-trifluoroethylene [P(VDF-TrFE)]. The nanocomposite PCLT/P(VDF-TrFE) film was used as the sensing film for pyroelectric sensors, whose detective merit was about 22.4% higher than that of sensors using pure P(VDF-TrFE). A 35 nm ITO film was deposited as the bottom electrode on PET plastic film substrate, on which PCLT/P(VDF-TrFE) was prepared by spin-coating, and Ni–Cr film was chosen as the upper electrode. The PET plastic film substrate could effectively decrease the thermal conductivity of the element and the ITO bottom electrode could reflect the infrared irradiation. The voltage responsivity was increased and the thermal fluctuation noise of the pyroelectric element was decreased significantly. The experimental results indicated that the specific detectivity of PCLT/P(VDF-TrFE) pyroelectric sensors based on PET film substrate reached 3.4E7 cm Hz^1/2 W⁻¹, more than two orders of magnitude higher than that of the sensors on bulk silicon substrate formed under the same conditions.     

Optofluidic device for ultra-sensitive detection of proteins using surface-enhanced Raman spectroscopy

An optofluidic device is reported in this paper that can highly improve the robustness of surface-enhanced Raman scattering (SERS) detection and provide fingerprint information of proteins with a concentration in the nanogram per liter range within minutes. Moreover, the conformational change of protein can also be obtained using this device. Fabricated by standard photolithography processes, the optofluidic device has a step microfluidic–nanofluidic structure, which provides robust SERS detection. The sensitivity of the device is investigated using insulin and albumin as target analytes at a concentration of 0.9 ng/L. The ability to detect conformational changes of proteins using this technology is also shown by probing these analytes before and after their denaturation.     

CuO nanowire-based humidity sensors prepared on glass substrate

The authors report the growth of CuO nanowires (NWs) on glass substrate and the fabrication of CuO NW humidity sensors. It was found that average length of the CuO NWs increased from 0.4 μm to 2.8 and 6 μm, respectively, as we increased the initial copper film thickness from 0.5 μm to 1 and 2 μm after oxidation. It was also found that resistance of the CuO NWs increased as we increased the relative humidity due to the p-type nature of CuO. Furthermore, it was found that samples with a larger initial copper film thickness and thus a longer average CuO NW length could provide a larger sensor response.     

Fabrication of micro sensors on a flexible substrate

Flexible micro temperature and humidity sensors on parylene thin films were designed and fabricated using a micro-electro-mechanical-systems (MEMS) process. Based on the principles of the thermistor and the ability of a polymer to absorb moisture, the sensing device comprised gold wire and polyimide film. The flexible micro sensors were patterned between two pieces of parylene thin film that had been etched using O₂ plasma to open the contact pads. The sacrificial Cr spacer layer was removed from the Cr etchant to release the flexible temperature and humidity sensors from the silicon substrate. Au was used to form the sensing electrode of the sensors while Ti formed the adhesion layer between the parylene and Au. The thickness of the device was 7 ± 1 μm, so the sensors attached easily to highly curved surfaces. The sensitivities of the temperature and humidity sensor were 4.81 × 10⁻³ °C⁻¹ and 0.03 pF/%RH, respectively. This work demonstrates the feasibility and compatibility of thin film sensor applications based on flexible parylene. The sensor can be applied to fuel cells or components that must be compressed.     

Fabrication of a highly bendable LCD with an elastomer substrate by using a replica‐molding method

Abstract— A highly bendable liquid‐crystal display was fabricated by using a multi‐functional elastomer substrate of self‐aligning LC molecules without any surface treatment. One of the two substrates is a plastic substrate while the other is a multi‐functional elastomer substrate produced by a replica‐molding technique. The multi‐functional elastomer substrate has pixel‐encapsulating walls that serve as spacers and provide mechanical stability and reproducibility against bending deformations. The highly bendable LCD demonstrates great flexibility, durability, and excellent electro‐optic performances in a highly bent state.     

Formation mechanism of subtrenches on cone-shaped patterned sapphire substrate

In this paper, the cone-shaped patterned sapphire substrates (PSS) were etched by an inductively couple plasma with BCl 3 as the reacting gas. The influence of the operating pressure and the RF bias power on subtrenches of the cone-shaped PSS and the formation mechanism of subtrenches were investigated. The profiles of patterns were characterized by FESEM (field emission scanning electron microscope). It showed that the subtrench size varied with the operating pressure and the RF bias power. As the operatin...     

基于柔性基底的压电能量收集器的设计

以PDMS为柔性基底设计的PVDF压电薄膜新型压电能量收集器压电性能良好,柔韧性强,可适应复杂的振动环境,具有广阔的应用前景.首先设计了具有柔性基底的压电能量收集器的结构;其次,用PVDF颗粒采用静电纺丝法制备了PVDF压电薄膜;最后,实验表明设计的压电能量收集器在振动频率为25 Hz,振动幅度为2 mm的激励下,开路输出峰值电压为8.38 V,输出功率密度为6.32 μW/cm2;经Ansys有限元分析,发现增大激励源的振动幅度,可以提高压电能量收集器的开路输出电压和输出功率.     

Mechanical properties and fracture analysis of glass substrate for PDPs

Abstract— A thermal shock test was carried out using high‐strain‐point glass substrates for plasma‐display panels. From the fracture analysis, the fracture stress was determined and compared with the initial edge strength. It was observed that the edge strength greatly decreased because of micro cracks that formed on the glass surface during testing. Therefore, it is important to prevent the formation of micro cracks in order to avoid failure as well as to minimize thermal stress in the process. Fatigue is also an important parameter in preventing the failure of the glass substrate when the stress on it lasts for a long period of time.