Showing papers on "Electroplating published in 2014"

Electroplating Cuprous Sulfide Counter Electrode for High-Efficiency Long-Term Stability Quantum Dot Sensitized Solar Cells

Abstract: Currently, Cu2S based on brass foil is the most commonly used counter electrode (CE) in high efficiency quantum dot sensitized solar cells (QDSCs) because of its superior catalytic activity to the polysulfide electrolyte redox couple. Regretfully, the brass substrate is limited by the shortcomings of corrosion by polysulfide electrolyte and lack of long-term stability. In order to combine the high catalytic activity of Cu2S and superior tolerance of fluorine doped tin oxide (FTO) glass to polysulfide electrolyte, Cu2S film on the FTO glass substrate (Cu2S/FTO) CE was prepared by electrodeposition of the copper film via a multipotential step technique followed by dipping into polysulfide methanol solution. The Cu2S film was proven to be composed by the interconnected nanoflakes, which ensures the highly catalytic activity to the polysulfide redox couple electrolyte in QDSCs. The CdSe quantum dot (QD) sensitized solar cells with the optimized Cu2S/FTO CE exhibit a power conversion efficiency (PCE) of 5.21%,...

Speciation, physical and electrolytic properties of eutectic mixtures based on CrCl3·6H2O and urea

Abstract: The electrodeposition of chromium is a technologically vital process, which is principally carried out using aqueous chromic acid. In the current study, it is shown that eutectic mixtures of urea and hydrated chromium(III) chloride provide a liquid which reduces the toxicological issues associated with the current aqueous Cr(VI) electroplating solution. Using EXAFS, mass spectrometry and UV-Vis spectroscopy, it is shown that chromium is present predominantly as a cationic species. Conductivities are higher than for most comparable ionic liquids. It is shown that the electrodeposition of chromium is electrochemically reversible, with a current efficiency much higher than in aqueous electrolytes. Surface tension and density measurements indicate that hole theory is a valid model to describe transport properties in these liquids. Bulk Cr deposits are not macrocrystalline but they are generally crack-free. The deposits have a hardness of 600 ± 10 Vickers and, as such, are comparable to deposits from aqueous systems.

Silicon Heterojunction Solar Cells With Copper-Plated Grid Electrodes: Status and Comparison With Silver Thick-Film Techniques

Abstract: Copper electroplating is investigated and compared with common silver printing techniques for the front metallization of silicon heterojunction solar cells. We achieve smaller feature sizes by electroplating, significantly reducing optical shadowing losses and improving cell efficiency by 0.4% absolute. A detailed investigation of series resistance contributions reveals that, at maximum power point, a significant part of the lateral charge-carrier transport occurs inside the crystalline bulk, rather than exclusively in the front transparent conductive oxide. This impacts optimization for the front-grid design. Using advanced electron microscopy, we study the inner structure of copper-plated fingers and their interfaces. Finally, a cell efficiency of 22.4% is demonstrated with copper-plated front metallization.

Large area solution processed transparent conducting electrode based on highly interconnected Cu wire network

Abstract: Virtually unlimited and highly interconnected Cu wire networks have been fabricated on polyethylene terephthalate (PET) substrates with sheet resistance of <5 Ω □−1 and transmittance of ∼75%, as alternatives to the commonly used tin doped indium oxide (ITO) based electrodes. This is a four step process involving deposition of commercially available colloidal dispersions onto PET, drying to induce crackle network formation, nucleating Au or Pd seed nanoparticles inside the crackle regions, washing away the sacrificial layer and finally, depositing Cu electrolessly or by electroplating. The formed Cu wire network is continuous and seamless, and devoid of crossbar junctions, a property which brings high stability to the electrode towards oxidation in air even at 130 °C. The flexible property of the PET substrate is easily carried over to the TCE. The sheet resistance remained unaltered even after a thousand bending cycles. The as-prepared Cu wire network TCE is hydrophobic (contact angle, 80°) which, upon UV–ozone treatment, turned to hydrophilic (∼40°).

Optically transparent hydrogen evolution catalysts made from networks of copper–platinum core–shell nanowires

Abstract: This article reports the fabrication of copper–platinum core–shell nanowires by electroplating platinum onto copper nanowires, and the first demonstration of their use as a transparent, conducting electrocatalyst for the hydrogen evolution reaction (HER). Cu–Pt core–shell nanowire networks exhibit mass activities up to 8 times higher than carbon-supported Pt nanoparticles for the HER. Electroplating minimizes galvanic replacement, allowing the copper nanowires to retain their conductivity, and eliminating the need for a conductive substrate or overcoat. Cu–Pt core–shell nanowire networks can thus replace more expensive transparent electrodes made from indium tin oxide (ITO) in photoelectrolysis cells and dye sensitized solar cells. Unlike ITO, Cu–Pt core–shell nanowire films retain their conductivity after bending, retain their transmittance during electrochemical reduction, and have consistently high transmittance (>80%) across a wide optical window (300–1800 nm).

A Study on the Effect of Pulse Electrodeposition Parameters on the Morphology of Pure Tin Coatings

Abstract: Pure Sn coatings are prepared by pulse current (PC) electrodeposition using aqueous acidic sulfate plating bath. The effects of various electroplating parameters such as current density, additive concentration, duty cycle, frequency, pH, bath temperature, and stirring rate (bath rotation) on the evolution of surface morphology of the coatings have been studied. The as-deposited coatings are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and surface profilometry. It is found that the current density, additive concentration, duty cycle, frequency, and pH have a major influence while temperature and stirring rate of the bath have a minor effect on the grain-size distribution. The mechanism involved in the morphology evolution and grain-size distribution due to the varying electroplating parameters has also been discussed.

Utilization of magnesium and zinc oxide nano-adsorbents as potential materials for treatment of copper electroplating industry wastewater

Abstract: Magnesium and zinc oxide nano-adsorbents were prepared for the removal of copper from industrial waste water. The size, morphology, chemical composition and structure of nano-adsorbents were established through powder XRD, SEM, AFM and EDX. The maximum adsorption capacities obtained for ZnO and MgO are 226 and 593 mg/g, respectively at initial pH of 3–4 when 0.3 and 0.2 g of adsorbent dose was utilized while maintaining the temperature at 70 °C. Though both nano-adsorbents were found effective in removing 92–98% Cu from industrial samples but MgO has better adsorption potential as compared to ZnO and found to obey pseudo-first order and Freundlich isotherm models. This study indicated that both nano MgO and nano ZnO can be used as effective, low cost and environment friendly nano-adsorbent for electroplating waste effluent treatment.

Effect of operational parameters on heavy metal removal by electrocoagulation

Abstract: In the present paper, the performance of electrocoagulation (EC) for the treatability of mixed metals (chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn)) from metal plating industrial wastewater (EPW) has been investigated The study mainly focused on the affecting parameters of EC process, such as electrode material, initial pH, distance between electrodes, electrode size, and applied voltage The pH 8 is observed to be the best for metal removal Fe-Fe electrode pair with 1-cm inter-electrode distance and electrode surface area of 40 cm(2) at an applied voltage of 8 V is observed to more efficient in the metal removal Experiments have shown that the maximum removal percentage of the metals like Cr, Ni, Zn, Cu, and Pb are reported to be 962, 964, 999, 98, and 995 %, respectively, at a reaction time of 30 min Under optimum conditions, the energy consumption is observed to be 5140 kWh/m(3) The method is observed to be very effective in the removal of metals from electroplating effluent

RTA-treated carbon fiber/copper core/shell hybrid for thermally conductive composites.

Abstract: In this paper, we demonstrate a facile route to produce epoxy/carbon fiber composites providing continuous heat conduction pathway of Cu with a high degree of crystal perfection via electroplating, followed by rapid thermal annealing (RTA) treatment and compression molding. Copper shells on carbon fibers were coated through electroplating method and post-treated via RTA technique to reduce the degree of imperfection in the Cu crystal. The epoxy/Cu-plated carbon fiber composites with Cu shell of 12.0 vol % prepared via simple compression molding, revealed 18 times larger thermal conductivity (47.2 W m–1 K–1) in parallel direction and 6 times larger thermal conductivity (3.9 W m–1 K–1) in perpendicular direction than epoxy/carbon fiber composite. Our novel composites with RTA-treated carbon fiber/Cu core/shell hybrid showed heat conduction behavior of an excellent polymeric composite thermal conductor with continuous heat conduction pathway, comparable to theoretical values obtained from Hatta and Taya model.

Electrochemical copper deposition from an ethaline-CuCl2·2H2O DES

Abstract: Cu electroplating was carried out using a pure ethaline melt, a 1:2 ratio of choline chloride and ethylene glycol, at room temperature by potentiostatic and galvanostatic methods. Hydrated cupric chloride was added to the pure ethaline melt. Polarisation data for cupric ion reduction to copper was collected using an RDE to determine where metal deposition was feasible. Smooth Cu deposits were obtained at − 4.7 × 10− 3 A/cm2 using 0.2 M CuCl2·2H2O at 25 °C at a current efficiency of (95 ± 5)% at a rotation speed of 700 rpm. XRD analysis of the deposit showed a polycrystalline face centred cubic structure with (111) texture. The crystalline size was 66 ± 10 nm with some internal strain. EDX analysis showed the presence of carbon and chlorine with copper in the deposit, which was due to the break-down of the DES. Several deposition processes were carried out from a single bath to examine bath stability. The bath was found to be stable when a soluble anode was employed, and became unstable when an insoluble anode was used due to other reactions proceeding at the cathode.

Study of the electrocoagulation of electroplating i ndustry wastewaters charged by nickel (II) and chromium (VI)

Abstract: The coagulation-flocculation is one of the techniqu es used for the treatment of industrial wastewaters . In this process, the principle of treatment consists on des tabilizing negative colloidal particles, by additio n of salts metal cations. The positive charge of cations compr esses the electrical double layer which surrounds t he colloidal particles characterized by a negative pot ential ( ζ, Zeta Potential). The iron and aluminum salts are the most used. Electrocoagulation is derived from the c onventional coagulation technique. The cations are generated in solution by electrolytic dissolution o f the metal electrodes. The main advantages of this process, highlighted by several authors, are low dose of coa gulant, reduction of salinity, enhanced reactivity of metal cations, oxidation of certain pollutants, compactne ss of installations, lower volume of sludge, and el imination of the small size colloidal particles. This paper repo rts a research work on wastewaters eletrocoagulatio n of an electroplating industry located in Casablanca (Moro cco). The goal is to carry out some tests of depoll ution applying two voltages 6 and 12 V on aluminum electrodes and to evaluate its performance. Abatement rat es determined for 6 V reached 57%, 63% and 42%, and 12 V for 77%, 88% and 66%, respectively for Chemical Oxygen Demand (COD), nickel and chromium. The elimination of these pollutants was done by adsorption o n aluminum hydroxide or its polymers which were formed in the pH range of this study, but also by the precipitation of nickel (II) and chromium (III) whi ch forms afterward the cathodic reduction of chromi um (VI) .

A short-range ordered-disordered transition of a NiOOH/Ni(OH)2 pair induces switchable wettability†

Abstract: By virtue of its amorphous structure with a short-range order feature, the inorganic nanoporous nickel oxyhydroxide (NiOOH) can reversibly and rapidly switch wettability by alternate treatments of environmental chamber (superhydrophobic) and UV/ozone (superhydrophilic). The switchable mechanism of the NiOOH/Ni(OH)2 pair arising from its exceptional intrinsic short-range order–disorder transition together with chemical composition change is highlighted for the first time, which significantly differs from the current stimuli-responsive materials. This distinct multifunctional thin film not only possesses reversible wettability but also is optically patternable/repairable and electrically conductive, which could be applicable in the manufacturing of various micro- and nanostructures. We demonstrate this potential in the rewritable two-dimensional (2D) microfluidic channels and wetting-contrast enhanced selective electroplating.

Control of electrolyte hydrodynamics for efficient mass transfer during electroplating

Abstract: Described are apparatus and methods for electroplating one or more metals onto a substrate. Embodiments include electroplating apparatus configured for plating highly uniform metal layers. In specific embodiments, the apparatus includes a flow-shaping element made of an ionically resistive material and having a plurality of channels made through the flow shaping element. The channels allow for transport of the electrolyte through the flow shaping element during electroplating. The channel openings are arranged in a spiral-like pattern on the substrate-facing surface of the flow shaping element such that the center of the spiral-like pattern is offset from the center of the flow shaping element.

Complexing agent study via computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit

Abstract: In this paper, we introduce a new environmentally friendly silver electroplating bath, employing 5,5-dimethylhydantoin (DMH) and nicotinic acid (NA) as complexing agents, based on the prediction of computational chemistry. An excellent silver electrodeposit with properties suitable for application in electronics packaging was obtained from the newly developed silver electroplating bath, and the electroplating bath is simple and stable. Moreover, the silver(I)-complexes in this bath possessed good complex stability. As a consequence, mirror-bright silver electrodeposits on copper substrates with excellent leveling capability, smooth and compact morphologies, high purity and conductivity, as well as excellent welding property could be realized by adopting this unique bath. Based on the performances of the plating bath and silver deposit, the introduced silver plating bath is a promising candidate for silver electrodeposition applied in microelectronics to replace the conventional cyanide silver electroplating baths.

Extremely anisotropic single-crystal growth in nanotwinned copper

Abstract: By electroplating the unidirectionally -oriented nanotwinned and fine-grained Cu on a Si wafer surface and followed by annealing at 400–500 °C up to an hour, we grow a number of extremely large -oriented single crystals of Cu of sizes from 200 to 400 μm, as illustrated by the left figure. By patterning the nanotwinned Cu film (middle figure), we grow an array of -oriented single crystals of Cu of sizes from 25 to 100 μm on Si after the annealing, as shown in the right figure.

Highly Conductive and Low Cost Ni-PET Flexible Substrate for Efficient Dye-Sensitized Solar Cells

Abstract: The highly conductive and flexible nickel-polyethylene terephthalate (Ni-PET) substrate was prepared by a facile way including electrodeposition and hot-press transferring. The effectiveness was demonstrated in the counter electrode of dye-sensitized solar cells (DSSCs). The Ni film electrodeposition mechanism, microstructure, and DSSC performance for the Ni-PET flexible substrate were investigated. The uniform and continuous Ni film was first fabricated by electroplating metallic Ni on fluorine-doped tin oxide (FTO) and then intactly transferred onto PET via hot-pressing using Surlyn as the joint adhesive. The obtained flexible Ni-PET substrate shows low sheet resistance of 0.18Ω/□ and good chemical stability for the I–/I3– electrolyte. A high light-to-electric energy conversion efficiency of 7.89% was demonstrated in DSSCs system based on this flexible electrode substrate due to its high conductivity, which presents an improvement of 10.4% as compared with the general ITO-PEN flexible substrate. This me...

Electroplating and Electroless Plating

Abstract: This chapter presents an overview of electroplating and electroless plating methods and discusses the basics of electroplating, alloy plating, and electroless plating. Zinc electroplating, decorative and hard chromium plating, nickel, copper, silver, gold, and tin electroplating are covered as well as electroless nickel and copper. Brass and zinc–nickel alloy plating, aluminum anodizing, and chromate conversion for aluminum and zinc are discussed. The focus is on plating bath constituents and their effect on deposition process. Besides general application areas and properties of each coating, some future trends are included.

Nickel–tungsten alloy brush plating for engineering applications

Abstract: Hard coating can improve the surface properties of a material beyond the capability of the substrate. For a long time, coatings such as hard nickel, hard chromium, hard alloys and hard composites have been developed for engineering applications due to the improved wear resistance. A newly-developed nickel–tungsten brush plating process has the potential as an alternative of electroplating of hard chromium for engineering application. The nickel–tungsten solution is based on the ammoniacal citrate bath, which can be conveniently brush plated just as brush plating of other metals or alloys. On the other side, hard chromium cannot be brush plated due to the exposure of hazardous hexavalent chromium exceeding the Occupational Safety and Health Administration (OSHA) limits. The nickel–tungsten alloy coating has been developed for engineering application. It is of nanocrystalline structure (~ 2 nm crystallite size) and demonstrates excellent hardness and wear resistance. The coating is 60% nickel, 40% tungsten by weight. Due to high tungsten content in the alloy, it is thermally stable. Moderately elevated temperatures (200–500 °C) do not cause grain size growth and softening as the case of most other hard coatings (such as hard chromium, nickel phosphorus). Actually, the nickel–tungsten alloy coating can be further hardened by exposure to high temperature of 200–500 °C for a short period of time. Beyond the hardness and wear properties, the coating has been further characterized by XRD, electronic and optical microscopy, hydrogen embrittlement, salt spray corrosion, tribology, axial fatigue, and other testing.

Stochastic Modeling of Polyethylene Glycol as a Suppressor in Copper Electroplating

Abstract: The desorption / adsorption of suppressor additive during Cu electroplating plays a critical role in the void-free filling of recessed features such as through-silicon vias (TSVs) used in 3-dimensional integration. A stochastic model was proposed for Polyethylene Glycol (PEG) as a suppressor additive in Cu electroplating. Using the proposed model, a program capable of simulating transient processes such as cyclic voltammograms (CVs) was developed. The steep change of current density due to suppressor desorption, as well as the characteristic hysteresis, observed in the CVs was shown in simulation. The dependency of PEG desorption / adsorption on various factors, including the bath composition, scan rate and molecular weight, was simulated. The simulation results were confronted side-by-side with the corresponding experimental measurements. An overall good qualitative match was shown.

Method for manufacturing semiconductor device

Abstract: A method for manufacturing semiconductor devices comprises: applying a dual pulse power to the semiconductor device during metal electroplating a part of the semiconductor device and applying ultrasonic energy to said semiconductor device during the metal electroplating.