Transparent conducting electrodes are essential components in various optoelectrical devices. Although indium tin oxide thin films have been widely used for transparent conducting electrodes, silver nanowire network is a promising alternative to indium tin oxide thin films owing to its lower processing cost and greater suitability for flexible device application. In order to widen the application of silver nanowire network, the electrical conductance has to be improved while maintaining high optical transparency. In this study, we report the enhancement of the electrical conductance of silver nanowire network transparent electrodes by copper electrodeposition on the silver nanowire networks. The electrodeposited copper lowered the sheet resistance of the silver nanowire networks from 21.9 Ω/□ to 12.6 Ω/□. We perform detailed X-ray diffraction analysis revealing the effect of the amount of electrodeposited copper-shell on the sheet resistance of the core-shell(silver/copper) nanowire network transparent electrodes. From the relationship between the cross-sectional area of the copper-shell and the sheet resistance of the transparent electrodes, we deduce the electrical resistivity of electrodeposited copper to be approximately 4.5 times that of copper bulk.

Tungsten trioxide (WO3) is a promising candidate as a photocatalyst because of its outstanding electrical and optical properties. In this study, we prepare WO3 thin films by electrodeposition and characterize the photocatalytic degradation of methylene blue using these films. Depending on the voltage conditions (static and pulse), compact and porous WO3 films are fabricated on a transparent ITO/glass substrate. The morphology and crystal structure of electrodeposited WO3 thin films are investigated by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. An application of static voltage during electrodeposition yields a compact layer of WO3, whereas a highly porous morphology with nanoflakes is produced by a pulse voltage process. Compared to the compact film, the porous WO3 thin film shows better photocatalytic activities. Furthermore, a much higher reaction rate of degradation of methylene blue can be achieved after post-annealing of WO3 thin films.

In this study, we synthesize tungsten oxide thin films by electrodeposition and characterize their electrochromic properties. Depending on the deposition modes, compact and porous tungsten oxide films are fabricated on a transparent indium tin oxide (ITO) substrate. The morphology and crystal structure of the electrodeposited tungsten oxide thin films are investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). X-ray photoelectron spectroscopy is employed to verify the chemical composition and the oxidation state of the films. Compared to the compact tungsten oxides, the porous films show superior electrochemical activities with higher reversibility during electrochemical reactions. Furthermore, they exhibit very high color contrast (97.0%) and switching speed (3.1 and 3.2 s). The outstanding electrochromic performances of the porous tungsten oxide thin films are mainly attributed to the porous structure, which facilitates ion intercalation/deintercalation during electrochemical reactions.

In this study, we investigated the overpotential of precipitation related to the catalytic activity of electrodes on the initial process of electrodeposition of Co and Co-Ni alloys on polycrystalline Cu substrates. In the case of Co electrodeposition, the surface morphology and the magnetic property change depending on the film thickness, and the relationship with the electrode potential fluctuation was shown. Initially, the deposition potential(−170 mV) of the Cu electrode as a substrate was shown, the electrode potential(Edep) at the Ton of electrodeposition and the deposition potential(−600 mV) of the surface of the electrodeposited Co film after Toff and when the pulse current was completed were shown. No significant change in the electrode potential value was observed when the pulse current was energized. However, in a range of number of pulses up to 5, there was a small fluctuation in the values of Edep and Eimm. In addition, in the Co-Ni alloy electrodeposition, the deposition potential(−280 mV) of the Cu electrode as the substrate exhibited the deposition potential(−615 mV) of the electrodeposited Co-Ni alloy after pulsed current application, the Edep of electrodeposition at the Ton of each pulse and the Eimm at the Toff varied greatly each time the pulse current was applied. From 20 % to less than 90% of the Co content of the thin film was continuously changed, and the value was constant at a pulse number of 100 or more. In any case, it was found that the shape of the substrate had a great influence.

탄소전극과 이온교환막을 결합한 축전식 탈염(CDI)을 이용하여 셀 구조와 셀 전위에 따른 구리 이온의 제거 특성을 연구하였다. 탄소전극과 이온교환막의 결 합 방식에 따라 4종류의 셀에 대해 실험한 결과 양이온, 음이온교환막을 결합한 셀(MCDI)에서 구리 이온의 제거율과 전하효율이 가장 높은 것으로 나타났다. 셀 전위에 따른 영향을 분석한 결과 0.6 V 이하에서는 전기이중층에 의한 전기 흡착(electrosoprtion)에 의해, 그리고 0.6 V 이상에서는 구리 이온의 전착 (electrodepostion)반응에 의해 구리 이온이 제거됨을 확인하였다. 또한 1.2 V 이상에서는 물이 전기분해되어 전하효율이 감소하였다. MCDI 셀의 운전결과 전하효율은 80% 정도로 구리 이온을 포함한 중금속 이온을 제거하는데 효과적인 것으로 판단되었다.

Vertically oriented nickel nanowire arrays with a different diameter and length are synthesized in porous anodic aluminium oxide templates by an electrodeposition method. The pore diameters of the templates are adjusted by controlling the anodization conditions and then they are utilized as templates to grow nickel nanowire arrays. The nickel nanowires have the average diameters of approximately 25 and 260 nm and the crystal structure, morphology and microstructure of the nanowires are systematically investigated using XRD, FE-SEM and TEM analysis. The nickel nanowire arrays show a magnetic anisotropy with the easy axis parallel to the nanowires and the coercivity and remanence enhance with decreasing a wire diameter and increasing a wire length.

A thin Cu seed layer for electroplating has been employed for decades in the miniaturization and integration of printed circuit board (PCB), however many problems are still caused by the thin Cu seed layer, e.g., open circuit faults in PCB, dimple defects, low conductivity, and etc. Here, we studied the effect of heat treatment of the thin Cu seed layer on the deposition rate of electroplated Cu. We investigated the heat-treatment effect on the crystallite size, morphology, electrical properties, and electrodeposition thickness by X-ray diffraction (XRD), atomic force microscope (AFM), four point probe (FPP), and scanning electron microscope (SEM) measurements, respectively. The results showed that post heat treatment of the thin Cu seed layer could improve surface roughness as well as electrical conductivity. Moreover, the deposition rate of electroplated Cu was improved about 148% by heat treatment of the Cu seed layer, indicating that the enhanced electrical conductivity and surface roughness accelerated the formation of Cu nuclei during electroplating. We also confirmed that the electrodeposition rate in the via filling process was also accelerated by heat-treating the Cu seed layer.

Chalcopyrite CuInSe2(CIS) is considered to be an effective light-absorbing material for thin film photovoltaic solarcells. CIS thin films have been electrodeposited onto Mo coated and ITO glass substrates in potentiostatic mode at roomtemperature. The deposition mechanism of CIS thin films has been studied using the cyclic voltammetry (CV) technique. Acyclic voltammetric study was performed in unitary Cu, In, and Se systems, binary Cu-Se and In-Se systems, and a ternaryCu-In-Se system. The reduction peaks of the ITO substrate were examined in separate Cu2+, In3+, and Se4+ solutions.Electrodeposition experiments were conducted with varying deposition potentials and electrolyte bath conditions. Themorphological and compositional properties of the CIS thin films were examined by field emission scanning electronmicroscopy (FE-SEM) and energy dispersive spectroscopy (EDS). The surface morphology of as-deposited CIS films exhibitsspherical and large-sized clusters. The deposition potential has a significant effect on the film morphology and/or grain size,such that the structure tended to grow according to the increase of the deposition potential. A CIS layer deposited at −0.6Vnearly approached the stoichiometric ratio of CuIn0.8Se1.8. The growth potential plays an important role in controlling thestoichiometry of CIS films.

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosionresistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carboncontent in the Ni-C composite plate fell in a range of 9.2~26.2at.% as the amount of carbon in the Ni Watt bath and theroughness of the composite were increased. The Ni-C composite with more than 21.6at.% C content did not show uniformlydispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion.The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results suchas passivation were not satisfactory; however, the Ni-C composite still displayed less than 10−4A/cm2 passivation currentdensity. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching thatof pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On theother hand, the surface resistivity of the Ni-C composite with 13at.% C content was increased by only 1%. It can be confirmedthat the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

The electro-deposition of compound semiconductors has been attracting more attention because of its ability torapidly deposit nanostructured materials and thin films with controlled morphology, dimensions, and crystallinity in a cost-effective manner (1). In particular, low band-gap A2B3-type chalcogenides, such as Sb2Te3 and Bi2Te3, have been extensivelystudied because of their potential applications in thermoelectric power generator and cooler and phase change memory.Thermoelectric SbxTey films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containingdifferent ratios of TeO2 to Sb2O3. The stoichiometric SbxTey films were obtained at an applied voltage of −0.15V vs. SCE usinga solution consisting of 2.4mM TeO2, 0.8mM Sb2O3, 33mM tartaric acid, and 1M HNO3. The stoichiometric SbxTey filmshad the rhombohedral structure with a preferred orientation along the [015] direction. The films featured hole concentrationand mobility of 5.8×1018/cm3 and 54.8cm2/V·s, respectively. More negative applied potential yielded more Sb content in thedeposited SbxTey films. In addition, the hole concentration and mobility decreased with more negative deposition potential andfinally showed insulating property, possibly due to more defect formation. The Seebeck coefficient of as-deposited Sb2Te3 thinfilm deposited at −0.15V vs. SCE at room temperature was approximately 118µV/K at room temperature, which is similarto bulk counterparts.

The recirculating electrochemical flow reactor developed at UCLA has been employed to fabricate nanostructured GMR multilayers. For comparison, Ni/Cu multilayers have been electrodeposited from a single bath, from dual baths and from the recirculating electrochemical flow reactor. For a magnetic field of 1.5 kOe, higher GMR (Max. -5%) Ni/Cu multilayers with low electrical resistivity (< 10 μΩ·cm) were achieved by the electrochemical flow reactor system than by the dual bath (Max. GMR = -4.2% and< 20 μΩ·cm) or the single bath (Max. GMR = -2.1% and< 90 μΩ·cm) techniques. Higher GMR effects have been obtained by producing smoother, contiguous layers at lower current densities and by the elimination of oxide film formation by conducting deposition under an inert gas environment. Our preliminary GMR measurements of Ni/Cu multilayers from the electrochemical flow reactor obtained at low magnetic field of 0.15 T, which may approach or exceed the highest reported results (-7% GMR) at magnetic fields > 5 kOe.

CuInSe2 (CIS) thin films were electrodeposited on Mo-coated glass substrates in acidic solutionscontaining Cu2+, In3+, and Se4+ ions, depending on deposition parameters such as deposition potential (-0.4 to-0.8V[SCE]) and pH (1.7 to 1.9). The influences of PH and deposition potential on the atomic composition ofCu, In, and Se in the deposited films were observed. The best chemical composition, approaching 1:1:2 atomicratio for the elements, was achieved at -0.5V (SCE) and pH 1.8. The as-deposited films showed low crystallinityand were annealed at 300 to 500oC for 30 min to improve crystallization. The surface morphologies,microstructures, and crystallographic structures of the annealed films as well as the as-deposited films wereanalyzed with AFM, SEM, and XRD. The defects of spherical particles appeared on the surfaces of CIS thinfilms in the as-deposited state and decreased in size and number with increasing annealing temperatures.Additionally, the crystallization to chalcopyrite structure and surface roughness (Ra) of the as-deposited thinfilms were improved with the annealing process.

Al-Cu alloy nano powders were produced by the electrical explosion of Cu-plated Al wires. The composition and phase of the alloy could be controlled by varying the thickness of Cu deposit on Al wire. When the Cu layer was thin, Al solid solution and were the major phases. As the Cu layer becomes thicker, Al diminished while phase prevailed instead. The average particle size of Al-Cu nano powders became slightly smaller from 63 nm to 44 nm as Cu layer becomes thicker. The oxygen content of Al-Cu powder decreased linearly with Cu content. It is well demonstrated that the electrodeposition combined with wire explosion could be simple and economical means to prepare variety of alloy and intermetallic nano powders.

10-50wt% 범위의 W을 함유하는 Ni-W 합금을 전기도금에 의해 제조하였다. 합금 중의 W 량은 전류밀도가 증가함에 따라 증가하였다. 전류밀도가 50mA/cm2이하인 경우 Ni-W합금은 미세한 결정립을 갖는 Ni의 고용체이었으며, 전류밀도가 50mA/cm2이상인 경우 비정질상으로 변화하였다. 이들의 결정질→비정질 천이는 W량이 40-46wt%인 구간에서 일어났으며 반각폭이 3배이상으로 증가하였다. 결정질 합금의 격자상수는 평형상태도 상의 W의 고용한계(약 30wt%)를 초과하는 40wt%까지 연속적으로 증가하는 것으로 나타나 Ni이 W을 과고용하고 있는 상태인 것으로 밝혀졌다. 비정질 Ni-W 합금은 400˚C이상의 온도에서 열처리하면 강한 [111]방향성을 가지며 재결정하였으며, 800˚C이상의 온도에서는 과고용된 W이 석출하였다. 합금조성 및 결정구조의 전류밀도 의존성을 이용하여 Ni-30%W과 Ni-50%W 합금층이 반복되는 결정질/비정질의 다층도금을 제조하였다.

Aluminum’s exceptional properties, such as its high strength-to-weight ratio, excellent thermal conductivity, corrosion resistance, and low neutron absorption cross-section, make it an ideal material for diverse nuclear industry applications, including aluminum plating for the building envelope of nuclear power plants. However, plating aluminum presents challenges due to its high reactivity with oxygen and moisture, thus, complicating the process in the absence of controlled environments. Plating under an inert atmosphere is often used as an alternative. However, maintaining an inert atmosphere can be expensive and presents an economic challenge. To address these challenges, an innovative approach is introduced by using deep eutectic solvents (DES) as a substitute for traditional aqueous electrolytes due to the high solubility of metal salts, and wide electrochemical window. In addition, DESs offer the benefits of low toxicity, low flammability, and environmentally friendly, which makes DESs candidates for industrial-scale applications. In this study, we employed an AlCl3-Urea DES as the electrolyte and investigated its potential for producing aluminum coatings on copper substrates under controlled conditions, for example, current density, deposition duration, and temperature. A decane protective layer, non-polar molecular, has been used to shield the AlCl3-Urea electrolyte from the air during the electrodeposition process. The electrodeposition was successful after being left in the air for two weeks. This study presents a promising and innovative approach to optimizing aluminum electrodeposition using deep eutectic solvents, with potential applications in various areas of the nuclear industry, including fuel cladding, waste encapsulation, and radiation shielding.