Non-aqueous Bath Research Articles

A review of developments in the electrodeposition of tin-copper alloys

The deposition of Sn–Cu binary alloys, mainly from aqueous electrolytes, is considered. The importance of tin–copper electrodeposits is summarised and the scope for plating them is highlighted. Sn–Cu (bronze) deposits are important in corrosion protection, decorative finishes, electronics and tribology. The past 20 years have seen a series of developments in the science and technology of bronze plating, including nanostructured deposits, environmentally friendly baths, such as methanesulfonic acid ones, and more ambitious coatings including multi-layers and composites. Among non-aqueous baths, room temperature ionic liquid electrolytes have received increasing attention. Our ability to realise controlled deposit morphology, composition and structure has been improved by newer electrolytes, improved electrolyte additives and pulse plating. The diversity of Sn–Cu deposit applications has extended to lithium batteries by newer layer structures such as composites, multi-layers and nanostructures), electrical control and relative bath/electrode movement. Electrochemical aspects of modern tin and bronze alloy deposition are illustrated by data from the authors' laboratory and elsewhere, which highlights the use of methanesulfonic acid electrolytes in tin alloy deposition due to their versatility and lack of environmental impact. A wide range of deposit composition, colour and surface finish are possible using suitable addition agents and by control of electrolyte flow and operating conditions. This review focuses on electrochemical voltammetry techniques together with morphological information from SEM imaging. Subject areas deserving further research and development are identified.

CuInSe2 thin film solar cells prepared by low-cost electrodeposition techniques from a non-aqueous bath

Highly crystalline and stoichiometric CIS thin films have been electrodeposited from non-aqueous bath at temperature 130 °C. Superstrate solar cell structure (FTO/CdS/CIS/Au) exhibited 4.5% power conversion efficiency.

Using galvanostatic electroforming of Bi1–xSbx nanowires to control composition, crystallinity, and orientation

Abstract

Electrodeposited CuIn1−xGaxSe2 thin films from non-aqueous medium for solar cell applications

Polycrystalline thin films of group I-III-VI, especially copper indium diselenide and its alloys with gallium (CuInxGa1−xSe2, CIGS) have proven to be a suitable absorbers layer to obtain high-efficiency solar cells. We have deposited CuInxGa1−xSe2 (CIGS) thin films by cost effective electrochemical technique from non-aqueous bath onto fluorine doped tin oxide (FTO) coated glass substrates. The electrochemical parameters have been investigated by cyclic voltammetry in a non-aqueous solution of ethylene glycol, consisting precursors of Cu, In, Ga, and Se. The structural, morphological, compositional, and optoelectronic properties of CIGS thin films were studied. The prominent X-ray diffraction peak (112) is systematically shifted from 2θ = 26.60 to 27.26°, with increase in the contents of Ga in CIGS precursor layer. The atomic percentage of Ga in CIGS thin film was further confirmed by energy dispersive x-ray analysis technique. Preliminary solar cell devices (Glass/FTO/CdS/CIGS/Au) showed photoactive behavior with good diode characteristics in dark and under illumination conditions.

Electrodeposition of Ni-Fe/BN Nano-Composite Coatings from a Non-aqueous Bath and Their Characterization

Electrodeposition of Ni-Fe/BN Nano-Composite Coatings from a Non-aqueous Bath and Their Characterization

To Study Effect of Temperature on Ultra Thin Films of Cdse by Electro Deposition Technique on Mirror Glass Substrate in Non-Aqueous Bath Solution

To Study Effect of Temperature on Ultra Thin Films of Cdse by Electro Deposition Technique on Mirror Glass Substrate in Non-Aqueous Bath Solution

Enhancement of photo-characteristics of Bi2Se3 thin films by post heat treatment at optimal temperature range

Thin films of Bi2Se3 have been deposited onto fluorine-doped tin oxide (FTO) – coated glass substrates from non-aqueous bath with the help of galvanostatic electrodeposition technique. The deposited films were subjected to heat treatment at different temperatures in aerated condition and characterized there after. The X-ray diffraction analysis showed the polycrystalline nature of the films and optical absorption technique employed on the as deposited films revealed the presence of direct transition with band gap energy 1.56eV which after annealing increased up to the value of 1.65eV. Stoichiometric composition of the film was determined through energy dispersive X-ray analysis. The stoichiometry was maintained within a short temperature range. The scanning electron micrographs of the films demonstrate a ‘fishing net’ type of highly porous structure with ‘foamy’ appearance. In order to ascertain the stability of the films towards anodic oxidation electrochemical polarization studies were conducted in aqueous medium followed by anodic stripping voltammetry to estimate the dissolved cations during polarization. Films annealed within an optimal temperature range were found to bear distinguished photoelectrochemical properties as regard to solar cell applications.

Electrochemical fabrication and characterization of p-CuSCN/n-ZnO heterojunction devices

p-CuSCN/n-ZnO heterojunction devices were prepared by depositing CuSCN electrochemically over a ZnO film previously deposited. The compact and smooth surface films of n-ZnO on FTO substrate were deposited electrochemically from a nonaqueous bath. The CuSCN films were characterized by cyclic voltammetry, chronoamperometry, SEM, energy-dispersive X-ray spectroscopy, and XRD measurements. The pure crystalline films of CuSCN with intrinsic trigonal pyramidal morphology over the ZnO films were obtained electrochemically by fixing the SCN/Cu ratio in the electrolytic bath 1.5:1 at 60 °C with −0.4 V deposition potential. Photocurrent measurements showed the increase of intrinsic surface states or defects in ZnO/CuSCN interface. The I–V characteristic of p-CuSCN/n-ZnO heterojunctions shows good rectification behavior with a rectification ratio of 250 at ±2 V. The value of 2.81 of the ideality factor calculated by fitting the semilogarithmic I–V data with the ideal diode equation revealed the better electrical contact between the smooth ZnO and CuSCN films than that of ZnO nano-rods and CuSCN crystallites.

Growth Mechanism and Morphology of ZnO/eosin-Y Hybrid Thin Films

Thin hybrid films of ZnO/eosin-Y were prepared by electrodeposition at-0.8 and-0.9 V in aqueous and non-aqueous baths at temperatures ranging from 40 to 90 ℃ with dye concentrations of 100 and 400 μmol·L-1.The films were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),energy-dispersive X-ray analysis (EDX),and absorption spectroscopy.The films prepared in a non-aqueous bath were non-porous and did not adsorb dye molecules on their surface.However,the films grown in aqueous media were porous in nature and adsorbed dye during the deposition of ZnO.Preferential growth of the film along the (002) face was observed,and the highest crystallinity was achieved when the film was deposited at 60 ℃.The maximum absorption was achieved for the films grown at 60 to 70 ℃,a deposition potential of-0.9 V,and a dye concentration of 100 μmol·L-1.

Highly-dispersed Ta-oxide catalysts prepared by electrodeposition in a non-aqueous plating bath for polymer electrolyte fuel cell cathodes

The Ta-oxide cathode catalysts were prepared by electrodeposition in a non-aqueous solution. These catalysts showed excellent catalytic activity and have an onset potential of 0.92 V(RHE) for the oxygen reduction reaction (ORR). The highly-dispersed Ta species at the nanometer scale on the carbon black was an important contributor to the high activity.

Electrochemical Deposition of Bi2(Te,Se)3 Nanowire Arrays on Si

Improving device performance and extending Moore's Law can be aided through active solid-state cooling, using thermoelectric (TE) materials with a high figure of merit (zT > 1). TE nanowires promise a path to higher zT, and electrochemical deposition (ECD) is a simple and scalable means for synthesizing TE nanowires. In this paper we report the ECD of 75 nm diameter nanowire arrays with a nominal composition of Bi2(Te0.95Se0.05)3 onto Si substrates. These nanowires show an improved level of compositional control than previously observed for TE nanowires in this system by ECD. This results from our new non-aqueous bath combined with recently described methods for template formation on Si.

Electrodeposition of Semiconductor n-CdTe and p-CdTe in Aqueous Medium and Aluminum Metal in a Nonaqueous Medium

Both n-type and p-type semiconductor CdTe were synthesized by electrodeposition from an aqueous deposition bath. Electrodeposition potential was found to be the key factor to synthesize the CdTe semiconductor of any specific conductivity type. The electrodeposition potentials of -0.4 V and 0.4 V versus Ag/AgCl generated the p-type and n-type CdTe respectively. The optimum deposition time was found to be 90 minutes for the best photoresponce of CdTe during water-splitting reaction. The indirect band gap energy of CdTe was found tunable from 1.55 to 2.00 eV by controlling both electrodeposition potential and the annealing time. Crystalline aluminum metal was deposited on a platinum electrode tip at room temperature in a non-aqueous deposition bath of anhydrous toluene containing aluminum bromide and the supporting electrolyte, tetra butyle ammonium bromide. Anhydrous condition was found to be the critical factor for the success of electrodeposition and production of aluminum metal at room temperature in a non-aqueous deposition bath.

Electrodeposition of Ni–SiC Composite from a Non-Aqueous Bath

Electrodeposited Ni–SiC composite deposits with SiC were produced on copper substrate using a non-aqueous organic solvent. -Methylformamide was found to be the most suitable solvent as it has a high dielectric constant (182) that allows high tolerance of the electrolyte in the bath, which is ordinarily not obtained in other solvents. The optimum condition arrived for deposition was nickel acetate , boric acid , SiC , current density , duration of electrolysis , and bath temperature . Satisfactory bright composite deposits were obtained, which were quite adherent to the copper base. Scanning electron microscope, energy-dispersive analysis by x ray, and X-ray diffraction studies have been performed to characterize the composites. Effect of current density on composition and microhardness of the composite deposits was investigated. Also, the effect of annealing on the microhardness of the deposits was studied.

Thin film growth of epitaxial gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide by electrodeposition

Thin films of gadolinium oxide, gadolinium yttrium oxide, and gadolinium cerium oxide were electrodeposited from non-aqueous baths. The films were on the order of 15 nm thick, and were grown epitaxially on textured nickel–tungsten substrates. The effect of deposition rate, annealing temperature and secondary metals on crystallinity and crystal orientation was investigated by X-ray diffraction and transmission electron microscopy. Slower rates, higher temperatures and low concentrations of yttrium improve the crystallinity of gadolinium oxide films, whereas the introduction of cerium induced polycrystallinity.

Enhanced photoelectrochemical activity of electro-synthesized CdS–Bi 2S 3 composite films grown with self-designed cross-linked structure

In the present investigation thin semiconductor films of CdS, Bi 2S 3 and their intermixed composite films have been electro-synthesized onto conducting glass substrate from nonaqueous bath containing various levels of the precursor salts of Cd 2+ and Bi 3+. Spectrophotometric measurements determine the band gap energies of the composite films at ∼2.53 eV and ∼1.37 eV corresponding to the binary systems CdS and Bi 2S 3, respectively. The film matrices exhibit a unique structure of cross-linked nanoporous Bi 2S 3 mesh containing spherical shaped CdS crystals distributed uniformly on the top of the surface as detected from the morphological studies through scanning electron microscopy and transmission electron microscopy. X-ray diffraction studies show crystalline structure of the films of which the chemical compositions were determined through energy dispersive analysis of X-ray. The film matrices enriched with Cd exhibit high dielectric property as obtained from the capacitance measurement and substantial thermal stability derived from thermogravimetry and differential thermal analysis. These films are found to be highly fluorescent in nature when subjected to spectrofluorimetric analysis. The Raman spectral data exhibit characteristic peaks that are associated with Cd–S and Bi–S bonds as well as the defects created by metal oxides. The spectrum also demonstrates that the changes in the relative position of the overtone bands are associated with compositional variation of the film surface. The study of electrochemical polarization of different films, derives the inherent stability of the matrices towards dissolution. This was followed by anodic stripping voltammetry to estimate the dissolved cations during polarization. Photoelectrochemical measurements demonstrate n-type semiconductivity of the films with high order of donor density and reasonable photoactivity under illuminated condition. It may be summarized that the blended intermix of CdS–Bi 2S 3 film acquires tailor made properties desirable for photoelectrochemical application and displays solar conversion efficiency of the order of ∼1%.

Fabrication of Fe:CdSe solar rechargeable (semiconductor–septum) storage cells

The Fe:CdSe thin films have been electrodeposited potentiostatically onto the stainless steel substrates, from non-aqueous bath containing (CH3COO)2·Cd·2H2O, SeO2 and FeCl3. The solar rechargeable (semiconductor–septum) storage cell is fabricated with the configuration C|1M polysulphide|n-Fe:CdSe|stainless steel||1M FeCl3 or 1M K4Fe(CN)6|C. The charging and discharging modes are studied and discussed. The comparison of FeCl3 and K4Fe(CN)6 based solar rechargeable storage cells, showed that FeCl3 based storage cell is superior than that of K4Fe(CN)6 based electrolyte because relatively charging time is minimum and discharging time is maximum. Thus it is concluded that the storage cell works not only as a generator but also as the storage of electricity.

Cd 1− xZn xTe thin films formed by non-aqueous electrochemical route

Polycrystalline thin films of graded band gap ternary cadmium zinc telluride (Cd 1− x Zn x Te) have been electrodeposited in a non-aqueous bath onto an indium tin oxide (ITO) coated glass cathode. Ethylene glycol was used as the non-aqueous medium. The cathodic electrodeposition of the ternary semiconductor Cd 1− x Zn x Te was studied using cyclic voltammetry in conjunction with photovoltammetry, optical, compositional, structural measurements and surface morphology. It is shown that the band gap of this alloy can be tuned from 1.42 to 2.21 eV by controlling the Cd:Zn mole fractions. X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX) measurements showed formation of Cd 1− x Zn x Te, where x varied between 0 and 1. It was found that the observed XRD reflections of all the samples index to the cubic phase of the Cd 1− x Zn x Te. The direction of the thermoemf developed in Cd 1− x Zn x Te films has also been shown to be opposite to the thermoemf for binary CdTe films. The resistivity rises with increase in the band gap indicating formation of a continuous solid solution of CdTe and ZnTe in the ternary phase Cd 1− x Zn x Te. The electrodeposited films have also been shown to possess polycrystalline pyramidal grains with compact and void free morphology.

High speed fabrication of aluminum nanostructures with 10 nm spatial resolution byelectrochemical replication

A high fidelity electrochemical replication technique for the rapid fabrication of Alnanostructures with 10 nm lateral resolution has been successfully demonstrated. Aluminumis electrodeposited onto a lithographically patterned Si master using a non-aqueous organichydride bath of aluminum chloride and lithium aluminum hydride at room temperature.Chemical pretreatment of the Si surface allows a clean detachment of the replicated Al foilfrom the master, permitting its repetitive use for mass replication. This high throughputtechnique opens up new possibilities in the fabrication of Al-related nanostructures,including the growth of long range ordered anodic alumina nanochannel arrays.

An approach for the development of protective coatings for the novel magnetostrictive material Tb0.3Dy0.7Fe1.92

A logical approach towards the development of protective metallic coatings for the newly developed pseudo-binary rare earth magnetostrictive material Tb0.3Dy0.7Fe1.92 has been put forth. Based on the proposal, experimental trials were conducted on nickel-based coatings, produced by electrodeposition and electroless plating techniques. Direct current electrodeposition of nickel was conducted using both aqueous and non-aqueous plating baths. Non-aqueous electrodeposition produced adherent nickel deposits unlike aqueous electrodeposition and electroless plating methods. The main cause of poor coating adherence in aqueous electrodeposition and electroless plating has been identified as excessive hydrogen evolution. The physical disintegration of the substrate due to hydrogen embrittlement has been briefly addressed.

Photoelectrochemical (PEC) studies on CdSe thin films electrodeposited from non-aqueous bath on different substrates

Thin films of CdSe were deposited by potentiostatic mode on different substrates such as stainless steel, titanium and fluorine tin-oxide (FTO) coated glass using non-aqueous bath. The preparative parameters were optimized to get good quality CdSe thin films. These films were characterized by X-ray diffraction (XRD), optical absorption and photoelectrochemical (PEC) techniques. XRD study revealed that the films were polycrystalline in nature with hexagonal phase. Optical absorption study showed that CdSe films were of direct band gap type semiconductor with a band gap energy of 1·8 eV. PEC study revealed that CdSe film deposited on FTO coated glass exhibited maximum values of fill factor (FF) and efficiency (η) as compared to the films deposited on stainless steel and titanium substrate.