薄膜测量的变间距不接触三电极技术

针对电气绝缘用薄膜材料相对电容率εr和介质损耗角正切tanδ的测量,IEC推荐了变间距不接触三电极方法。为了配合我国国家标准的制定及推广,自行研制了高精度的空气媒质变间距不接触三电极系统,其测量电极直径为38mm,保护间隙宽度为0.2mm,满足极薄(厚度小于30μm)的薄膜材料测量的特殊技术需求,可将εr的测量误差控制在5%以内,tanδ可测到10-5数量级。通过大量试验及理论分析,系统研究了影响测量准确度的关键因素,并将两种不接触电极方法进行了比较,以供相关技术人员作为实际应用时的借鉴和参考。

薄膜热电极尺寸效应分析及试验研究

薄膜型热电极作为薄膜热电偶结构的核心部位,其尺寸设计对热电偶功能及性能的实现起着重要作用;文章研究了热电偶电极薄膜的尺寸效应,建立了薄膜热电偶热电及热传导机理数学模型,分析了热电极尺寸对热电偶静态及动态特性的影响,设计并制作了不同尺寸规格热电极的薄膜热电偶,对热电极的尺寸效应物理性能开展了试验研究,试验结果表明热电偶电极薄膜厚度与动态响应时间呈正相关,长度、宽度、面积等尺寸参数对热电偶特性无明显影响,为薄膜热电偶电极尺寸设计提供了理论基础与工程依据。

热电池用正极-电解质一体化复合薄膜的制备及性能研究

面向新一代小型化轻量化武器装备对热电池电源的实际需求,通过流延涂布工艺制备了正极-电解质一体化复合薄膜极片。所制备的一体化薄膜具有良好的机械强度,极片厚度仅为180 mm,远小于传统粉末压片工艺制得极片的厚度。将一体化薄膜极片与锂硼负极组装成单体电池进行放电,放电结果表明,在100 mA/cm^(2)的电流密度下,450℃时单体电池的峰值电压为2.01 V,截止电压1.0 V时,放电时间达到125 s,对应比容量可达1806 A·s/g;同时,单体电池内阻也相对较低,仅为40 mΩ。

制备方法对二氧化钛粉末薄膜光电极性能的影响研究

目的研究光电功能涂层制备方法对粉末薄膜光电极的光电转换效率的影响。方法采用喷涂法制备光电材料的FTO薄膜光电极,观察其表面形貌,通过研究光电流和光电位的变化评价光电材料的光电转换效率,并与点涂法和电泳法制备的光电极进行对比分析。结果喷涂法制备的二氧化钛FTO薄膜光电极性能优于其他两种方法制备的电极,在3.5%氯化钠溶液中,光电位变化更稳定,压降大于500 m V,光电流变化大于60μA/cm^2。结论喷涂法制备光电极能够提高半导体粉末材料的光电化学效率,是一种可推行的薄膜光电极制备方法。

涂覆法制备TiO_2薄膜光电极及催化性能研究

用涂覆法制备了 Ti O2 薄膜光电极 ,并对其进行了 XRD和 SEM的表征。以该电极为工作电极 ,铜片为对电极 ,饱和甘汞电极为参比电极 ,建立了三电极光电催化体系 ,研究了此 Ti O2薄膜的光电催化性能以及外加偏压对反应速率的影响。结果表明 :利用涂敷法制备 Ti O2 薄膜电极是一种较好的方法 ;外加偏压可抑制光生电子—空穴的复合 ,提高苯酚的光催化效率 ;外加阳极偏压的光电催化速率优于外加阴极偏压的速率 ;在一定范围内 ,外加阳极偏压越大 。

全薄膜折边极箔电力电容器

目前已研制成功一种折边极箔的全膜电力电容器,它具有极好的电气性能和30年以上的使用寿命。根据电场计算,这种折边箔片能降低电极边缘的电场强小,并度,并能采用比平滑非折边极箔高得多的额定场强。从而,使电力电容器的体积减具有较低的介质损耗,较高的局部放电起始电压和可靠性。

Photoelectrocatalytic reduction of CO_2 into formic acid using WO_(3-x)/TiO_2 film as novel photoanode

A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.

In situ investigation of atmospheric corrosion behavior of PCB-ENIG under adsorbed thin electrolyte layer

The effects of relative humidity (RH) on a printed circuit board finished with electroless nickel immersion gold (PCB-ENIG) under an adsorbed thin electrolyte layer (ATEL) were investigated in situ via the measurement of cathodic polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to clearly elaborate the corrosion behavior of PCB-ENIG in the atmospheric environment. Results indicated that the cathodic process of PCB-ENIG under ATEL was dominated by the reduction of dissolved oxygen, corrosion products, and H2O. The cathodic current density of PCB-ENIG increased progressively with increasing RH. Moreover, its cathodic current density in the solution was greater than that under ATEL. This result demonstrated that the diffusion process was not the controlling step during the limiting reduction of cathodic oxygen. When the polarization potentials were located in a more negative region, the cathodic polarization current density gradually decreased under 75% and 85% RH. Notably, the anodic process became the controlling step in the extremely thin liquid film during the remainder of the experiment.

Physical and Electrochemical Characterization of LiCo0.8M0.2O2 （M=Ni,Zr） Cathode Films for All-solid-state Rechargeable Thin-film Lithium Batteries

LiCo0.8M0.2O2 （M=Ni,Zr） films were fabricated by radio frequency sputtering deposition combined with conventional annealing methods. The strtuctures of the films were characterized with X-ray diffraction （XRD）, Raman spectroscopy and scarming electron microscopy （SEM） techniques. It was shown that the 700 ℃- annealed LiCo0.8M0.2O2 has an α-NaFeO2 like layered structure. All-solid-state thin-film batteries （TFBs） were fabrieated with these films as the cathode and their eleetroctemical performances were evaluated. It was found that doping of electrochemically active Ni and inactive Zr has different effects on the structural and elcctrochemical properties of the LiCoO2 cathode films. Ni doping increases the discharge capacity of the film while Zr doping improves its cycling stability.

光源对TiO_2光催化剂性能的影响

采用阳极氧化法制备了 Ti O2 /Ti薄膜半导体光电极 ,并测试了该电极在 2 5 4 nm和365 nm两种光源照射下苯酚的转化过程。实验表明 :2 5 4 nm波长光源下苯酚的降解以均相光氧化反应为主 ;365 nm波长的光照下 ,以多相光催化反应为主 ,电极上加偏压能明显提高反应速率。在三电极体系中 ,用频响分析系统测试了光电极的交流阻抗图谱 ( EIS) ,分析

STUDY ON DIAMOND LIKE CARBON THIN FILM BY FILTERED VACUUM ARC DEPOSITION

Diamond like carbon thin film is successfully deposited on silicon, titanium and stainless steel substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges are established on a graphite cathode in the system with a toroidal macroparticle filter. A cathode activating magnetic field and a filtered magnetic field to collimate the plasma beam are applied. Ion current convected by the plasma beam is measured with a negatively biased probe. It is shown that the magnetic field of the coils located on the plasma duct has a strong influence on cathode spot behavior. Orthogonally the designed experiments are carried out to optimize the deposition parameters of arc stability. Finally, the diamond like carbon thin films are studied by scanning electron microscope (SEM) and Raman spectrum.

OTFT with Bilayer Gate Insulator and Modificative Electrode

An organic thin-film transistor （OTFT） with an OTS/SiO2 bilayer gate insulator and a MoO3/AI electrode configuration between gate insulator and source/drain electrodes has been investigated. A thermally grown SiO2 layer is used as the OTFT gate dielectric and copper phthalocyanine（CuPc） is used as an active layer. This OTS/SiO2 bilayer gate insulator configuration increases the field-effect mobility, reduces the threshold voltage, and improves the on/off ratio simultaneously. The device with a MoO3/Al electrode has shown similar Ids compared to the device with an Au electrode at the same gate voltage. Our results indicate that using a double-layer of electrodes and a double-layer of insulators is an effective way to improve OTFT performance.

Experimental Research of DLC Film Deposited by Filtered Vacuum Arc Evaporation

Diamond like carbon (DLC) films was grown successfully on silicon, titanium and high speed steel (HSS) substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges were established on a graphite cathode in this home built system with a toridal macroparticles filter. Ion current convected by the plasma beam was measured with a negatively biased probe. It was shown that the magnetic field of the coils located on the plasma duct has a strong influence on ion current. Scanning electron microscope (SEM), atomic force microscope (AFM) and Raman spectrum are used to study the DLC films. Tribological behaviors of the deposited film are also studied.

Analysis and simulation of lateral PIN photodiode gated by transparent electrode fabricated on fully-depleted SOI film

A novel device, lateral PIN photodiode gated by transparent electrode （LPIN PD-GTE） fabricated on fully-depleted SOI film was proposed. ITO film was adopted in the device as gate electrode to reduce the light absorption. Thin Si film was fully depleted under gate voltage to achieve low dark current and high photo4o-dark current ratio. The model of gate voltage was obtained and the numerical simulations were presented by ATLAS. Current-voltage characteristics of LPIN PD-GTE obtained in dark （dark current） and under 570 nm illumination （photo current） were studied to achieve the greatest photo-to-dark current ratio for active channel length from 2 to 12 /am. The results show that the photo-to-dark current ratio is 2.0×10^7, with dark current of around 5×10^-4 pA under VGK=0.6 V, PrN=5 mW/cm2, for a total area of 10μm×10μm in fully depleted SOI technology. Thus, the LPIN PD-GTE can be suitable for high-grade photoelectric systems such as blue DVD.

Study of Depolarization Field Influence on Ferroelectric Films Within Transverse Ising Model

An improved transverse Ising model is proposed by taking the depolarization field effect into account. Within the framework of mean-held theory we investigate the behavior of the ferroelectric thin film. Our results show that the influence of the depolarization field is to flatten the spontaneous polarization profile and make the films more homogeneous, which is consistent with Ginzburg Landau theory. This fact shows that this model can be taken as an effective model to deal with the ferroelectric film and can be further extended to refer to quantum effect. The competition between quantum effect and depolarization field induces some interesting phenomena on ferroelectric thin films.

Efficiency analysis of a-SiC:H thin film light emitting diodes

The hole injection,the radiative recombination and the device luminescent efficiencies of amorphous silicon carbide thin film p-i-n junction light emitting diodes are quantitatively calculated,and the effect of the carrier(especially the hole) injection and recombination processes on the device luminescent characteristics are revealed.Without considering the device junction temperature,it is found that the device luminescent efficiency mainly depends on the hole injection efficiency at low field and the hole radiative recombination efficiency at high field respectively.The theoretical analyses are in well agreement with the experimental results.

Significant Enhancement in Built-in Potential and Charge Carrier Collection of Organic Solar Cells using 4-（5-hexylthiophene-2-yl）-2,6-bis（5- trifluoromethyl）thiophen-2-yl）pyridine as a Cathode Buffer Layer

An electron transporting material of TFTTP （4-（5-hexylthiophene-2-yl）-2,6-bis（5-trifluoromethyl）thiophen-2-yl）pyridine） was investigated as a cathode buffer layer to enhance the power efficiency of organic solar cells （OSCs） based on subphthalocyanine and C60. The overall power conversion efficiency was increased by a factor of 1.31 by inserting the TFTTP interfacial layer between the active layer and metallic cathode. The inner mechanism responsible for the performance enhancement of OSCs was systematically studied with the simulation of dark diode behavior and optical field distribution inside the devices as well as the characterization of device photocurrent. The results showed that the TFTTP layer could significantly increase the built-in potential in the devices, leading to the enhanced dissociation of charge transfer excitons. In addition, by using TFTTP as the buffer layer, a better Ohmic contact at C60/metal interface was formed, facilitating more efficient free charge carrier collection.

TiO2 Nanoparticles Produced by Electric-Discharge-Nanofluid-Process as Photoelectrode of DSSC

Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.

One-step fabrication of TiO2/graphene hybrid mesoporous film with enhanced photocatalytic activity and photovoltaic performance

We synthesized a mesoporous film based on TiO2-reduced graphene oxide(RGO)hybrids using a one-step vapor-thermal method without the need for an additional annealing process.The vapor-thermally prepared TiO2-graphene hybrid(VTH)features unique structures with an ultra-large specific surface area of^260 m^2 g^-1 and low aggregation,giving rise to enhanced light harvesting and increased charge generation and separation efficiency.It was observed that a mesoporous film with uniform pore distribution is simultaneously obtained during the VTH growth process.When a 5.0 wt%RGO VTH film was used as the active layer in photocatalysis,the highest photocatalytic activity for degradation of methyl orange was achieved.For another,when a 0.75 wt%RGO VTH film was used as the photoanode in a dye-sensitized solar cell,the power conversion efficiency reached 7.58%,which represents an increase of 73.1%compared to a solar cell using an a photoanode of pure TiO2 synthesized by a traditional solvothermal method.It is expected that this facile method for the synthesis of TiO2/graphene hybrid mesoporous films will be useful in practical applications for preparing other metal oxide/graphene hybrids with ultra-high photocatalytic activity and photovoltaic performance.