Electrochemical behavior of potentiodynamically deposited cobalt oxyhydroxide (CoOOH) thin films for supercapacitor application

In the present study, we report, for the first time, the synthesis of cobalt oxyhydroxide thin films on inexpensive stainless steel substrate using potentiodynamic electrodeposition method. These films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) techniques. The orthorhombic crystal structure was revealed by the X-ray diffraction study. The FT-IR spectrum confirmed the formation of cobalt oxyhydroxide. The SEM studies showed the nanoflakes-like morphology with an average thickness of 100 nm. The cyclic voltammetry study of the cobalt oxyhydroxide films in 1 M KOH showed maximum specific capacitance of 449 F g^?1 at scan rate of 5 mV s^?1.     

An improvement on redox reversibility of cobalt oxyhydroxide in nickel hydroxide electrodes

In this paper, two kinds of cobalt oxyhydroxide conductive networks were introduced into nickel hydroxide electrodes by different methods—electrochemically-oxidized (EO) or chemically oxidized (CO) CoOOH on the surface of nickel hydroxide particles. The redox behaviors of them were studied by using cyclic voltammetry (CV) and X-ray diffraction (XRD) measurements. It shows that because CoOOH(CO) has better redox reversibility than CoOOH(EO), the structure of the former can be kept when nickel hydroxide electrodes are subjected to a negative potential. Thus, 98.5% capacity retention is demonstrated on nickel/metal-hydride (Ni–MH) batteries with CoOOH(CO) after being imposed over-discharge state storage; on the contrary, only 81.4% capacity retention is found on the batteries with CoOOH(EO).     

Microstructure and magnetic properties of electrodeposited cobalt films

Cobalt films were electrodeposited onto both iron and copper substrates from an aqueous solution containing a mixture of cobalt sulfate, boric acid, sodium citrate, and vanadyl sulfate. The structural, intermetallic diffusion and magnetic properties of the electrodeposited films were studied. Cobalt electrodeposition was carried out in a passively divided cell aided by addition of vanadyl sulfate to keep the counter electrode clean. The divided electrolytic cell with very negative current densities cause the electrodeposited Co to adopt a face-centered cubic (fcc) structure, which is more magnetically reversible than the hexagonally close-packed (hcp) structured Co. The coercive field is also significantly less in the fcc-electrodeposited cobalt than in the hcp. SEM images show dense, uniform Co films without any cracks or porosity. Beside the deposition current, thickness of the film was also found to affect the crystal orientation particularly on iron substrates. Diffusion of cobalt film into the iron substrate was studied under reduced environment and a fast process was observed.     

金属铝离子注入掺杂制备氧化锌铝薄膜的研究

本文采用中频孪生非平衡磁控溅射设备制备非晶ZnO薄膜,再以不同剂量的铝离子注入法制备氧化锌铝薄膜.并采用X射线、扫描电镜、四极电阻仪、霍尔效应等方法测量和分析了原始沉积的和铝金属离子注入掺杂ZAO膜在不同温度下退火的组织结构、形貌、电阻与工艺的关系.结果表明,金属离子注入铝的方法制备氧化锌铝薄膜的电阻值随着注入剂量的增加而减小,呈线形关系,透明度均在90%左右,在铝离子注入剂量大于1×1016时,透光率在75%～80%.研究表明,该方法可以任意调整铝离子的注入剂量,获得要求特性的ZAO薄膜.     

普鲁士兰恒电流法沉积在聚苯胺膜上的性能表征

在ITO玻璃上分别用循环扫描伏安法和恒电流法依次沉积了聚苯胺(PANI)和普鲁士兰(PB)薄膜,对PANI和PB单层膜及复合膜的红外光谱进行了分析,讨论了3种薄膜的循环伏安曲线和紫外-可见吸收光谱.结果表明,在所选沉积条件下,制备出了电活性高的电致变色复合薄膜,600nm处的着色效率η=57.3.用钾离子掺杂的聚(2-丙稀酰胺-2-甲基丙磺酸)(PAMPS)作为离子导体,电导率σ达到8.691×10-3S/cm,组装的器件循环50次后,CV曲线变化较小,性能稳定.     

Characteristics of pulse electrodeposited PbS thin films

PbS thin films were deposited for the first time using the pulse electrodeposition technique at different duty cycles in the range of 9 to 50% and at room temperature using lead nitrate and sodium thiosulphate. The thickness of the films increased from 0.5 to 1.0 μm with increase of duty cycle. The films were polycrystalline and exhibited cubic structure. The band gap of the films deposited at 50% duty cycle is 0.42 eV. The resistivities of the films decreased from 0.9 to 0.5 × 10⁵ ohm cm as the duty cycle increased. Films with grain size in the range of 20 to 35 nm were deposited. Films with refractive index varying in the range of 4.45–3.75 with increase of wavelength were obtained. Films with higher photosensitivity and higher detectivity compared to earlier reports were obtained.     

Electrical properties of electrodeposited CdTe thin films

The electrical properties of electrodeposited CdTe thin films have been studied. The temperature-dependent electrical conductivity data obtained have been used to determine the conductivity type and semiconductor parameters (E _g, B, and α) of the films.     

Orientation enhancement of polycrystalline ZnO thin films through thermal oxidation of electrodeposited zinc metal

The polycrystalline ZnO thin films with (002) orientation enhancement were prepared by annealing of electrodeposited metallic Zn films from the ethylene glycol solution of zinc acetate without using any catalyst and template. The morphologies of the thin films were evolved from the nanoplate to the nanocolumn structures with increasing of annealing temperature from 100 °C to 500 °C. SEM and XRD studies indicated that the ZnO nanocolumns were enhanced in the (002) orientation along their length direction. The UV-vis absorption spectra of the ZnO films obtained by annealing at 300 °C and 500 °C were carried out and their band gaps were 3.18 eV and 3.20 eV, respectively. A possible growth mechanism of the ZnO nanostructures responsible for the morphologies and orientation evolution was discussed.     

Influence of cobalt ion implantation on optical properties of titanium dioxide thin films

Nano-crystalline TiO₂ thin films were synthesized by using sol-gel and spin-coating techniques on glass substrates for photo-catalytic applications. Prior to deposition, a TiO₂ colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. In this study, the deposited TiO₂ coating with a grain size of 13 ± 2 nm was uniform without aggregation. Co ion implantation into the as-calcined TiO₂ thin films was conducted with fluences of 1 × 10¹⁵-1 × 10¹⁶ doses/cm² at 40 keV. In addition to the emission of TiO₂, the photoluminescence study showed the presence of another Co-related optical center at 405 nm in the Co-implanted TiO₂ thin films. Due to the strong capability of forming impurity compounds between the energetic cobalt ions and TiO₂, the photoluminescence emission and UV-Vis absorption efficiencies were improved.     

Growth and characterisation of electrodeposited ZnO thin films

The electrochemical method has been used to deposit zinc oxide (ZnO) thin films from aqueous zinc nitrate solution at 80 °C onto fluorine doped tin oxide (FTO) coated glass substrates. ZnO thin films were grown between − 0.900 and − 1.025 V vs Ag/AgCl as established by voltammogram. Characterisation of ZnO films was carried out for both as-deposited and annealed films in order to study the effect of annealing. Structural analysis of the ZnO films was performed using X-ray diffraction, which showed polycrystalline films of hexagonal phase with (002) preferential orientation. Atomic force microscopy was used to study the surface morphology. Optical studies identified the bandgap to be ∼ 3.20 eV and refractive index to 2.35. The photoelectrochemical cell signal indicated that the films had n-type electrical conductivity and current-voltage measurements showed the glass/FTO/ZnO/Au devices exhibit rectifying properties. The thickness of the ZnO films was found to be 0.40 μm as measured using the Talysurf instrument, after deposition for 3 min. Environmental scanning electron microscopy was used to view the cross-section of glass/FTO/ZnO layers.     

氧化钨薄膜电致变色机理的探讨

研究磁控溅射生成的氧化钨薄膜处于电解液系列中的循环伏安特性，充电电流厦光学特性．采用配体场理论来解释氧化钨薄膜在电场作用下，锂离子注入引起薄膜变色的现象，认为注入的锂离子破坏了薄膜界面层内氧化钨分子的八面体结构的对称性，在内部静电场和外部电场的共同作用下，鸽离子d轨道的五重简并能级分裂。从而使得薄膜对可见光产生d-d吸收，导致氧化钨薄膜变色．     

Transient bleaching pulse shapes in electrochromic polysiloxane thin films

Transient bleaching currents are examined for a series of electrochromic carbazole-modified polysiloxane thin films. The shape of the bleaching currents is found to be sensitive to the type of counter-ion employed and the initial density of counter-ion charge that is deposited in the films during the colouration stage. Pure space-charge-limited (SCL) transport of counter-ions that posses a well-defined mobility is inconsistent with the observed pulse shapes and a modified SCL model that involves fast and slow mobility sites is proposed. The modified SCL model may describe a variety of transient bleaching pulse shapes (including current overshoots) as charge is removed from the electrochromic films and the counter-ions are constrained to transfer from slow to fast discharge sites.

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Magnetic properties of cobalt rare-earth thin films

This paper describes the magnetic properties of dc sputtered thin films of Co-Gd and Co-Sm in various compositions. Magnetic moment density, hysteresis loop coercivity and squareness, and rotational hysteresis loss measurements are reported. Crystallite and domain sizes were observed with an electron microscope for a few compositions. A tentative model of magnetization reversal is proposed for some of the compositions.     

The magneto-optical properties of thin cobalt films

Experimentally measured magneto-optical properties of magnetic materials are usually analysed using a phenomenological approach in which the permittivity is considered as a skew-symmetric tensor. Measurements of the real and imaginary parts of both the optical and the magneto-optical elements of this sensor in the region 1.0–2.5 eV are presented for a series of seven thin (108-13.4 nm) cobalt films. The prominent features of the results are remarkably consistent from film to film.     

The substrate influence on the magnetization of nickel electrodeposited thin films

The effects of diffusion of substrate copper atoms into the film as well as substrate stresses on both saturation magnetization and coercive force of annealed electrodeposited Ni films have been investigated.     

塑料基MoO3电致变色薄膜性能

采用溶胶-凝胶工艺,在镀有ITO透明电极的聚对苯二甲酸乙二酯（PET）基体上制备了MoO3电致变色薄膜.用FT-IR和TG-DTA分析了薄膜的成分和热稳定性,用分光光度计、电化学工作站研究了其在1 mol/L的LiClO4碳酸丙烯酯（PC）液体电解质中的电致变色性能.结果表明：薄膜主要成分是含有水合过氧化氢的无定形MoO3;着、退色前后可见光透过率变化△T为40%,在550 nm时的致色效率为44.8 cm^2/C,经1000次循环,电色性能变化很小;着色速度和对比度随着色电压的增加而增加,Li^0的扩散和Li＋的迁移分别控制着着色速度和退色速度.