基于CMOS工艺的抗光噪声神经微电极

为了减小神经电极的宽度,提高电极在光照下的抗噪声干扰能力,提出了一种基于0.18μm CMOS工艺的抗光噪声神经微电极。采用CMOS的多层布线代替传统电极导线的单层排布,并将电极衬底接地以有效减小光噪声。阐述了基于CMOS工艺的神经电极结构设计、制备过程与结构表征,并对所制备的神经电极进行了电化学阻抗测试和光噪声测试。该神经电极宽度仅为70μm,实验证明:1kHz频率下电极的阻抗一致性好,且在1mW/mm2的光遗传常用光辐照下,该电极的噪声电压仅为0.07~0.08mV,远低于传统硅电极12~13mV的噪声幅值。结果表明,基于CMOS工艺的神经电极抗光噪声能力远优于传统硅电极,对硅基微电极在光遗传中的应用具有重要意义。     

海洋电极电化学噪声原理及工艺探讨

模拟海洋电极的使用环境,以电极的电化学反应过程为基础,介绍了电化学噪声的产生机理、影响因素及分类;对比分析了不同烧结温度下电极噪声性能的差异.结果显示,电极的微观结构和导电特性共同影响其噪声性能.研究表明,将烧结温度设在465℃附近烧制的电极的表面缺陷少、对电信号传导的影响低、噪声性能优,进而为电极的烧结工艺指出了方向.     

基于半球谐振陀螺电极刻蚀的三维平衡调整方法

曲面电极刻蚀技术是半球谐振陀螺的关键技术之一。为满足半球谐振陀螺高精度和高性能的要求,针对激励罩和读出基座的电极刻蚀工艺,该文提出了一种新的调整方法——三维平衡调整法。通过X、Y、Z方向的位移传感器检测器件与参考平台的间距,根据间隙差距的大小进行相应的调整。试验验证表明,该方法能有效减小半球谐振陀螺电极刻蚀的误差,满足器件的各项性能参数。该方法原理简单,具有定位精度高,工艺易实现的优点,对半球谐振陀螺电极刻蚀工艺具有较好的工程应用价值。     

基于柔性干电极的肌电信号无线采集系统设计

传统Ag/AgCl湿电极存在柔韧性差、稳定性不高等缺点,已不能满足应用于智能可穿戴设备采集表面肌电信号(sEMG)的需求。提出一种通过微电子机械系统(MEMS)技术制备柔性干电极的方法,并针对柔性干电极的特点设计一套便携式16通道sEMG无线采集系统。通过光刻、刻蚀、聚二甲基硅氧烷(PDMS)形貌转移等工艺制成面积1 cm~2、厚度1 mm、底部直径80μm、高度143μm、中心距160～240μm的柔性微针阵列干电极。无线采集系统将采集到的sEMG进行放大、滤波、A/D转换和无线传输后,由LabVIEW编写的上位机进行波形显示和数据存储。整个采集装置尺寸为6 cm×2.5 cm×1.5 cm,电池容量为200 mA·h,充电5 min可在室外50 m范围内工作4 h左右。该无线采集装置配合柔性干电极提取sEMG具有采集通道多、稳定性好、传输距离远、实时显示波形、生物兼容性好等优点。     

极间距可调的ECT系统差分传感器设计

针对电容层析成像传感器相邻电极间耦合电容引起的测量噪声及传统传感器需根据被检测管道的外径变化而需重新制作安装的问题，设计了一种便携式、电极对于管道轴心距离（极间距）可调节的差分电极传感器。通过控制模块调节极间距，使单一传感器能够适用于外径在60～100 mm动态范围内变化的管道测量。采用差分电极结构，解决了传感器无法固定合适长度的径向电极的问题，消除了传感器内部分寄生器件引起的测量噪声。实验结果表明，新型传感器可实现多种不同外径的管道的检测，差分电极的使用提高了多相流成像质量。     

基于ZnO/Al2O3缓冲层制备耐高温SAW器件电极

为了声表面波(SAW)器件能在高温环境(不小于1 000 ℃)中工作,该文设计并在La3Ga5SiO14压电衬底上制作Pt/ZnO/Al2O3多层复合薄膜电极,利用ZnO/Al2O3组合缓冲层增强了Pt薄膜电极在极端高温条件下的导电稳定性。制备的SAW器件在经历3次1 000 ℃高温热处理后仍保持稳定的回波损耗系数S11。实验结果表明,ZnO/Al2O3组合缓冲层结构在提高SAW器件电极高温导电稳定性方面具有一定的潜在应用价值。     

硅基微型超级电容器三维微电极结构制备

为增大硅基微型超级电容器电极结构表面积,以提高电极的电荷存储能力,采用感应耦合离子刻蚀(ICP)技术制备了超级电容器三维微电极结构,研究了刻蚀、钝化气体流量和射频功率及电极电压等工艺参数对所制电极结构的影响。要取得较理想的结果,须根据刻蚀的一般规律和所用设备的具体特点,结合实际要求来确定工艺参数。在掩膜宽度为25μm时,所制三维电极结构表面规则平整,比二维电极结构表面积增大8.38倍。     

局部环形电极压电驱动器正交异性分析

该文提出了一种平面内具有正交异性的局部环形电极压电驱动器,研究了该压电驱动器的分支电极中心距、分支电极宽度和电极区域角对压电驱动器正交异性的影响。研究结果表明,局部环形电极压电驱动器的方向性强,在平面内有明显的正交异性。减小分支电极中心距、增大分支电极宽度及电极区域角,有利于提高该压电驱动器有电极区域的驱动性能。当电极中心距为0. 8 mm,电极度为0.4 mm,元件厚为0.5 mm,加载电压为200 V时,局部环形电极压电驱动器的径向夹持应力横向效应系数能达45.60,径向自由应变横向效应系数能达1.82。局部环形电极压电驱动器有电极区域的径向夹持应力可达2.46 kPa,径向自由应变可达6.3×10~(-5)。因此,局部环形电极压电驱动器在指定方向上可实现高的力学性能。     

双电层电容器中单/双面涂覆电极的电化学性能比较

以KOH为活化剂,采用微波加热石油焦一步法制备了微孔活性炭。采用循环伏安和恒流放电法研究了双电层电容器中单面和双面涂覆的活性炭电极电化学性能。活性炭的亚甲基蓝吸附值为247.8mg·g–1,N2吸/脱附结果表明,活性炭比表面积为1037m2·g–1,微孔孔容为0.54m3·g–1。结果表明,1000次循环后,双面涂覆电极的比容、比容保持率和两电极电容器的能量密度保持率分别为227.3F·g–1、96.6%和97.4%均高于单面涂覆电极;而双面涂覆电极的内阻仅为0.42Ω,小于单面涂覆电极的内阻。     

等间距螺旋电极压电驱动器制备与静态性能测试

基于阿基米德螺线方程提出一种等间距螺旋电极压电驱动器,该文分析了其电极结构与驱动原理,采用丝网印刷法对该驱动器螺旋电极进行了印制,并完成待测元件的制备。搭建了位移测试平台测试元件的静态性能,并对其静态的径向位移及平面扭转角进行了研究。试验结果表明,直径?25 mm、厚2 mm、电极宽0.6 mm、电极中心距1.2 mm的等间距螺旋电极压电驱动器在频率0.5 Hz、电压200 V的正弦激励信号作用下,径向峰值位移可达1.02μm,为传统电极压电元件的1.57倍,扭转角度可达0.12 mrad,与传统型压电驱动器相比,该元件具有较大的径向位移输出,且产生的扭转角度明显。     

Characterization of signals and noise rejection with bipolarlongitudinal intrafascicular electrodes

Longitudinal intrafascicular electrodes (LIFEs) are fine electrodes threaded into the extracellular space between axons in peripheral nerves or spinal roots. The authors are developing these electrodes for application in functional electrical stimulation and in basic physiology. An area of concern in chronic recording application of LIFEs is the possibility of electromyogram and other external noise sources masking the recorded neural signals. The authors characterized neural signals recorded by LIFEs and confirmed by three independent methods that increasing interelectrode spacing for bipolar LIFEs increases signal amplitude. The spectrum of neural signal from bipolar and monopolar LIFE lies between 300 Hz and 10 kHz. The amplitude of the spectrum increases with increasing interelectrode spacing, although the distribution is not affected. Single unit analysis of LIFE recordings show that they record selectively from units closest to the electrode active site. Units with conduction velocities ranging from 50-120 m/s were identified. Extraneural noise, as stimulus artifact or electromyogram, is much reduced with bipolar LIFE recording, as compared to monopolar recordings. Relative improvement in neural signal to extraneural noise increases with interelectrode spacing up to about 2 mm. Since there is no further improvement beyond 2 mm, the authors conclude that the preferred interelectrode spacing for bipolar LIFEs is 2 mm     

Antimicrobial Peptide Functionalized Conductive Nanowire Array Electrode as a Promising Candidate for Bacterial Environment Application

Conductive polymer electrodes are widely used for electrical signal detection owing to their unique mechanical, redox, and impedance characteristics. However, the performance of electrodes is compromised due to the interference of adhered bacteria and most of the scientists have not taken the microbial environment into consideration during electrode design. Here, a facile approach to construct antimicrobial peptide (AMP) functionalized polypyrrole nanowire array conductive electrodes (PNW‐AMP) is reported. Instead of compromising the electrochemical properties as the other antibacterial agents do, the PNW‐AMP electrodes exhibit excellent redox and low interfacial impedance properties. More importantly, the PNW‐AMP can eliminate bacterial adhesion and maintain electrochemical stability simultaneously in the microbial microenvironment for a long time. The antibacterial rate of the PNW‐AMP electrode reaches 95.8% after exposing the electrode to air for one month, while the charge transfer resistance ( R_ct) value only increases by 9% at a bacterium (Escherichia. Coli ) concentration of 1 × 10⁴ colony forming unit (CFU) mL^?1. This research makes it possible to construct highly stable conductive polymer electrodes for bacterial environment electrical signal detection.     

Inkjet-printed Ag grid combined with Ag nanowires to form a transparent hybrid electrode for organic electronics

Networks of silver nanowires (AgNW) have been shown to facilitate high transparency, high conductivity, and good mechanical stability. However,the loose characteristic and local insulation problems due to gaps between the nanowires limit their application as electrodes. This study investigates an inkjet-printed Ag grid combined with AgNW to form a transparent hybrid electrode. The printed Ag grid on AgNW film connects the gaps between the Ag nanowires to increase the overall electric conductivity. The printed Ag-grid/AgNW hybrid electrodes have low resistivity (22.5 Ω/□) while maintaining a high transmittance (87.5%). These values are similar to standard indium tin oxide (ITO) on glass which has resistivity of 20Ω/□ and transmittance of 89% at 550 nm. In addition, these hybrid electrodes are also very flexible when fabricated on a photopolymer substrate. A spin-coating process combined with a peel-off process enable the fabrication of flexible ultra-smooth Ag-grid/AgNW electrodes. We tested the transparent and flexible electrode as the anode of a flexible organic light emitting diode (F-OLED). The light emitting layer of the F-OLED is 35 nm thick tris-(8-hydroxyquinoline) aluminum doped with 0.5% 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-(1)-benzopyropyrano(6,7-8-I,j)quinolizin-11-one. The maximum brightness and current efficiency of the F-OLED are 10000 cd/m² and 12 cd/A, respectively, even when bent around a radius of 2 mm. The good performance of the device with Ag-grid/AgNW hybrid electrodes show that enhanced conductive inkjet-printed Ag nanoparticles combined with Ag nanowires can produce high quality electrodes for flexible organic optoelectronic devices.     

Effect of electrode density and measurement noise on the spatial resolution of cortical potential distribution

The purpose of the present study was to examine the spatial resolution of electroencephalography (EEG) by means of inverse cortical EEG solution. The main interest was to study how the number of measurement electrodes and the amount of measurement noise affects the spatial resolution. A three-layer spherical head model was used to obtain the source-field relationship of cortical potentials and scalp EEG field. Singular value decomposition was used to evaluate the spatial resolution with various measurement noise estimates. The results suggest that as the measurement noise increases the advantage of dense electrode systems is decreased. With low realistic measurement noise, a more accurate inverse cortical potential distribution can be obtained with an electrode system where the distance between two electrodes is as small as 16 mm, corresponding to as many as 256 measurement electrodes. In clinical measurement environments, it is always beneficial to have at least 64 measurement electrodes.     

Spatially resolved photocurrent mapping of efficient organic solar cells fabricated on a woven mesh electrode

Flexible organic photovoltaic devices may soon find applications in various fields, such as portable electronics or building‐integrated photovoltaics, occupying market niches that are currently not covered by the prevailing photovoltaic technology based on silicon and other inorganic materials. For these applications, there is an urgent need to replace the commonly used indium tin oxide by transparent and electrically conductive materials that can be processed cost‐effectively by large‐area compatible printing and coating processes. Here, we fabricated P3HT/PCBM organic solar cells with a power conversion efficiency of 3.1% on a flexible, transparent and conductive woven fabric electrode. The electrode is produced by a roll‐to‐roll process and consists of a polymer‐embedded fibre/metal wire grid. Metal wires protrude as little as 5 µm from the electrode plane, providing electrical contact points on a smooth surface suitable for thin film deposition. The use of spatially resolved photocurrent mapping experiments showed a high level of detailed information, with the unexpected indication that there probably exists a maximum in the cell performance versus mesh size opening and that woven fabric electrodes with largest geometrical open area do not necessarily perform better. Copyright © 2012 John Wiley & Sons, Ltd.     

NiCu双金属电极电催化析氢

采用恒电流共沉积方法制备了具有纳米结构的NiCu双金属电极。采用线性扫描、塔菲尔曲线、电流时间曲线及电化学阻抗谱对NiCu双金属电极电催化析氢的性能进行了测试;并且还利用X射线衍射(XRD)、扫描电子显微镜(SEM)和循环伏安测试手段对其组成、相结构和表面形貌进行了表征和分析。实验结果表明,NiCu双金属电极的电催化析氢性能明显优于Ni电极或Cu电极,这可能与Cu和Ni的协同作用有关。在所研究的NiCu双金属电极中,NiCu0.04具有较好的电化学析氢活性,这主要与其电化学反应电阻较小和比表面积较大有关。     

Flexible Transparent Supercapacitors: Materials and Devices

The progressive development of flexible transparent portable electronic devices is in urgent need of matching power sources. Flexible transparent supercapacitors (FTSCs) are the core resources due to their high optical transmittance, endurable mechanical flexibility, excellent electrochemical performance, and facilely accessible device configuration. This review organizes the rational design of nanostructured electrode materials toward FTSCs. First, the structure, mechanism, and property of FTSCs are introduced. Then, the design principles of diverse electrode materials are discussed to achieve flexible transparent conductive electrodes (FTCEs) with different figure of merits (both electrical FoMe and capacitive FoMc), mechanical strength, and environmental stability. Following the achievements in multifunctional FTSCs focusing on film-supercapacitors, micro-supercapacitors, electrochromic supercapacitors, photo-supercapacitors, and battery-like supercapacitors are also highlighted. Finally, the current challenges and future perspectives on viable materials in the construction of FTSCs to power portable electronics are outlined.     

基于铂黑的微针电极阵列表面修饰方法

由于微针电极阵列尖端直径小,空间分辨率高,可以记录单个神经元的放电活动,已成为神经信号记录的首选。但商用微针电极阵列的阻抗较高,降低电极阻抗有利于提高信噪比,改善记录信号质量。采用超声电镀铂黑的方法对微针电极表面进行修饰。测试结果表明铂黑修饰后的微针电极电化学性能优异,1 kHz处阻抗约为2.5 kΩ,相比裸金电极降低了两个数量级,电荷存储量增加到2.988×10-6 C。此外,机械超声测试和循环伏安扫描测试证明了电极具有良好的机械和电化学稳定性。这使铂黑修饰的微针电极阵列有望在体内植入研究中实现电极所需的高灵敏度及高空间分辨率。     

金属诱导多晶硅电极用于液晶显示透反功能的设计

溶液法金属诱导晶化(S-MIC)的p型掺杂多晶硅薄膜,具有较好的电学特性和近似半透半反的光学特性,可作为透、反两用功能液晶显示器件(LCD)的像素电极材料.但MIC多晶硅薄膜的透射与反射在红.绿和蓝三色区存在着一定的差异,势必导致合成白光的"畸变".为此,作者在MIC(大晶畴)多晶硅材料制成的电极上,在制备并光刻TFT源、漏电极铝金属引线的同时,光刻出不同面积的铝反射片来平衡和补偿经过MIC多晶硅薄膜透过与反射的红、绿、蓝三基色光,有效地进行红、绿、蓝三基色出光光谱的校正.校正结果表明在可见光范围内,其红光、绿光和蓝光处的透射率和反射率基本符合白光平衡的要求;由此形成了具有透、反两用功能的LCD多晶硅像素电极技术.     

银端电极对叠层片式铁氧体电感器电感量的影响

借助射频阻抗/材料分析仪、XRD及SEM,研究了三种银端电极对叠层片式铁氧体电感器电感量的影响。结果发现:银端电极中银比例越高,电感器在电镀后的电感量下降幅度越大;对于使用银质量分数为99.49%的AG78银端电极浆料制作的外形尺寸为1.6 mm×0.8 mm×0.8 mm、电感量为(10±0.1)μH的叠层片式铁氧体电感器,其电镀后的电感量最大降幅达到15.38%。