Step Electrochemical Deposition Research Articles

Highly stable electrodeposited 2D Mn0.2Co0.8 LDH nanoplatelets based symmetric supercapacitor electrode

High performance Mn0.2Co0.8 layered double hydroxide (LDH)-based binder free supercapacitor symmetric electrode is fabricated via single step electrochemical deposition. The synthesized Mn0.2Co0.8 electrode shows specific capacitance of 370.58–141.17 F/g (315–120 C/g) at 2–40 A/g within potential range −0.45–0.4 V along with 172.72% capacitance retention for 9000 GCD cycles. Additionally, a symmetric supercapacitor is also made utilizing Mn0.2Co0.8 LDH both as cathode and anode. The high potential of synthesized electrode as a supercapacitor material is shown by achieving a specific capacitance of 106.91–34.57 F/g at 0.5–3 A/g within a cell voltage of 0 to 0.8 V, as well as outstanding cyclic stability over 5000 GCD cycles. Red LEDs are used to analyze the real world application of the fabricated symmetric supercapacitor for energy storage and it is assumed that the future portable electrical systems and gadgets might benefit from the device based on the reported material and synthesis technique.

Unveiling charge dynamics of Co3S4 nanowalls/CdS nanospheres n-n heterojunction for efficient photoelectrochemical Cr(VI) detoxification and N2 fixation

Photoelectrochemical (PEC) conversion of solar energy is a sustainable and ecological approach as it offers green energy carriers, renewable fuels as well as environmental remediation. Herein, a polyaniline-coated anodized stainless-steel mesh (PANI-ASSM) was supported n-n heterojunction of CdS nanosphere (NSs)-Co3S4 nanowalls (NWs) by a simple step by step electrochemical deposition method. The PEC performance of the developed photoanode was then assessed toward Cr(VI) detoxification and N2 fixation. The PL, UV-Vis, electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS), cyclic voltammetry (CV), transient photocurrent (TPC), chronopotentiometry, and Bode phase tests also proved the excellent PEC performance and significant stability of this catalyst. UV–vis, Urbach energy (UE), Mott-Schottky (M-S), and linear sweep voltammetry (LSV) results coupled to the Robert Mulliken method confirmed the formation of robust n-n CdS-NSs-Co3S4-NWs heterojunction with viable band edge potential for Cr(VI) detoxification and N2 fixation; while PANI only acted as a powerful bridge to transfer the photo-generated electrons to ASSM support. The possible mechanism was investigated by experimental and electrochemical analysis which suggested a 3-electron-coupled Cr(VI) and 6-electron-coupled N2 reduction pathway. Such a PEC exhibited considerable electrocatalytic performance due to effective electron-hole separation with an ammonia yield and Cr(VI) reduction of 12.33 µg/mol.h NH3 and 90.61%, respectively. This work presented a new paradigm for the illustrative design of promising photoanodes for renewable fuel production and detoxification performance.

Single step electrochemical deposition for the fabrication of CZTS kesterite thin films for solar cells

The high absorption coefficient and direct optical band gap of a kesterite Cu2ZnSnS4 (CZTS) makes it very promising absorber material in the manufacturing of high efficiency and low-cost thin film photovoltaic cells. Single step electrochemical deposition of CZTS quaternary compound thin films on Indium tin oxide (ITO) substrates is reported in this work. The films were obtained from aqueous solutions at room temperature. The key objective of this work is to examine the effect of annealing temperature on CZTS thin films. Sulfurization of thin films was performed under different temperature range from 400 °C to 550 °C. Good crystal structure was achieved at temperature 500 °C with the complexing agent of trisodium citrate. Deposited films material composition was evaluated by analyzing UV–visible spectroscopy, EDS, FE-SEM and XRD. The thin film with good morphological, structural and optical (1.51 eV) properties was achieved at temperature 500 °C. The results reported in this work will provide an imperative guideline for efficient low-cost design of CZTS thin films.

Single Step Electrochemical Deposition of p-Type Undoped and Co2+ Doped FeS2 Thin Films and Performance in Heterojunction Solid Solar Cells

Undoped and Co2+ doped FeS2 thin films (Co compositions are 1 to 5 mole%) were deposited on indium tin oxide glass substrate by a single step electrochemical deposition (ECD) method at low temperature (70 °C). Glancing angle X-ray diffraction (GAXRD) and Raman spectra showed that as-deposited undoped and Co2+ doped FeS2 thin films have a cubic pyrite structure without any trace of orthorhombic marcasite phase. Co2+ doping does not affect the cubic structure of FeS2 thin films with a strong (111) plane preferred orientation in all the doped thin films. The height profiling of 3 mole% of Co2+ doped FeS2 thin film by atomic force microscopy revealed a smooth surface with uniform distribution of particles and low roughness values. Co2+ (3, 4 and 5 mole%) doped thin films show a strong absorption peak in the higher wavelength region. Magnetic measurement reveals that Co2+ doping into the FeS2 lattice induces ferromagnetism. The Co2+ in FeS2 thin films acts as the acceptor and the original p-type conductivity is retained. Solar light irradiation with the intensity of 100 mW/cm2 on Co2+ (3 mole%) doped FeS2 thin film cell resulted in a power conversion efficiency of 5.42%.

One step electrochemical deposition and reduction of graphene oxide on screen printed electrodes for impedance detection of glucose

Graphene has emerged as one of the promising tools for bio-detections as it has high surface area with strong electrochemical properties. In present work, a sensitive electrochemical sensor based on the specific boronic acid-diol binding for glucose sensing was established. The sensor was consisted of 3-aminophenylboronic acid (APBA) and reduced graphene oxide (rGO). Before the modification of electrodes, graphene oxide (GO) and APBA composites (GO/APBA) were compounded by the dehydration condensation reaction. The rGO and APBA composites (rGO/APBA) were reduced from GO/APBA and deposited onto the screen printed electrodes through cyclic voltammetry, simultaneously. With the rGO/APBA functionalized electrodes, the glucose molecule could be detected in the range from 0.1mM to 50mM, which could satisfy the clinical application. In order to verify the sensitivity and selectivity of the rGO/APBA functionalized electrodes, GO/APBA, and rGO alone functionalized electrodes were also explored for glucose determination. Results showed that rGO/APBA modified electrodes possessed superior electron conductivity, which promoted the detection properties in impedance spectroscopy. In our study, an easy and simple cost-effective modification method was proposed by one step electrochemical reduction and deposition technique of rGO on screen printed electrodes. With specific modification, the rGO functionalized electrodes provided a sensitive and selective detection of biological analytes.

Magnetic properties of nickel nanowires decorated with cobalt nanoparticles fabricated by two step electrochemical deposition technique

We demonstrate fabrication and magnetic characterization of novel nanostructures composed of Ni nanowires decorated with Co nanoparticles by two step etching and electrochemical deposition in polycarbonate template. Structural analysis confirmed the formation of nickel nanowires with diameter of 62 nm which are surrounded by cobalt nanoparticles of about 15 nm in diameter. By electron microscopy analyses it is evident that the nanoparticles are distributed on the surface of the nanowires. Analysis of magnetization data indicates that ferromagnetic Ni nanowires exhibit an easy axis of magnetization parallel to the wire long-axis while the angular dependence of coercivity indicates that magnetization reversal occurs through the curling process in these nanowires. An exchange bias accompanied by vertical shift in magnetization was observed below ∼20 K, measured under a cooling field of 1 kOe, which is attributed to the spin interactions between the spin-glass like surface layer and ferromagnetic core of the nanowires and nanoparticles.

One Step Fabrication of Au Nanoparticles‐Ni‐Al Layered Double Hydroxide Composite Film for the Determination of L‐Cysteine

AbstractThis paper reports the fabrication of Au nanoparticles (Au NPs)‐Ni‐Al layerd double hydroxide (LDH) composite film by one step electrochemical deposition on the surface of a glass carbon electrode from the mixture solution containing HAuCl4 and nitrate salts of Ni2+ and Al3+. Improved conductivity was obtained by Au NPs codeposited on LDH film. The synergic effect of LDHs and Au NPs dramatically improves the performance of L‐cysteine electro‐oxidation, displaying low oxidation peak potential (0.16 V) and high current response. Thus the electrode was used to sense L‐cysteine, showing good sensitivity and selectivity.

A Novel Method for the Growth of Cu2O/ZnO Heterojunctions

A novel two step electrochemical deposition method for the synthesis of ZnO/Cu2O heterojunctions is reported. ZnO nanorods were grown on seeded oxidized silicon substrates and were subsequently employed as working electrodes for the electrodeposition of Cu2O in the same aqueous formamide solution using Zn and Cu foils as counter-electrodes respectively. Single crystalline Cu2O particles grow on top of the single crystalline and vertical to the substrate ZnO nanorods. Varying the growth parameters different Cu2O morphologies can be obtained, ranging from isolated cube and truncated cube particles to a continuous layer.

Tuning the Initial Electronucleation Mechanism of Palladium on Glassy Carbon Electrode

Electrochemical metal nucleation is the method for the formation of metal nanoparticles on the electrode surface. Studying the early stage of electronucleation is simpler than other methods as the driving force for nucleation is achieved by changing deposition potentials and concentration of metal ions. In this work, the potential step electrochemical deposition of palladium was studied from its chloride solution at room temperature on glassy carbon electrode surface. The nucleation mechanism was studied by analysis of the resulting current transients. Accordingly, the initial electro-nucleation mechanism of palladium nanoparticles was found to be varying depending on deposition conditions such as deposition potential and palladium concentration. It can be changed from 3D instantaneous (for all deposition potentials studied and in higher electrolytic concentration) to 3D progressive nucleation mechanism (for lower deposition potential and lower electrolytic concentration). In addition, the nucleation rate for each deposition potential as well as the concentration has been determined. The nucleation rate in this research is used to calculate the nuclei density and found to decrease from more negative deposition potential to more positive deposition potential in agreement with the observed shift in electronucleation mechanism.

Gold nano-island arrays on silicon as SERS active substrate for organic molecule detection

Gold islands forming highly controlled arrays have been fabricated by two potential step electrochemical deposition method using nanopatterned Si surface templates. In the present work, the Raman scattering studies realized using 11-mercaptoundecanoic probe molecule showed that such structures exhibit an enhanced Raman signal compared with nanostructured physical deposited thin gold film on flat silicon substrate and can be valued as surface-enhanced Raman scattering substrates. Besides the more appropriate management of nano-island arrays distribution, the high ratio of their Raman signals can be explain by the epitaxial-like growth mechanism of the metallic nano-islands, clearly showed by X-ray diffraction studies. Furthermore, the substrates enabled reproducibility and stability detection due to the chemically assembling of organothiol molecules, the X-ray photoelectron spectroscopy studies confirming formation of the thiolate species which corresponds to AuS bonds, and also, the unwanted ‘hot-spots’ are missing, which make them suitable for high sensitivity biosensing applications.

A new deposition process for Cu(In,Ga)(S,Se)2 solar cells by one-step electrodeposition of mixed oxide precursor films and thermochemical reduction

One step electrochemical deposition of Cu-In-Ga mixed oxide precursor film on Mo substrate is carried out by potentiostatic method in an acidic nitrate based electrolyte. Deposition parameters, such as ions concentration, deposition time and potential, enable to control accurately the layer composition and thickness. The oxide layer is subsequently transformed into metallic alloy by thermal reduction, and selenized into Cu(In,Ga)Se2 compound. First cell results show conversion efficiency up to 9.4%.

Platinum/graphene hybrid film as a counter electrode for dye-sensitized solar cells

A platinum nanoparticles/graphene nanosheets (PtNP/GN) film was prepared on rigid fluorine-doped tin oxide substrate by using a facile one step electrochemical deposition method, and the film was used as counter electrode for dye-sensitized solar cell (DSSC). The cyclic voltammetry, electrochemical impedance spectroscopy and Tafel curves measurements indicated that the PtNP/GN CE has higher conductivity and better electrocatalytic activity for I3−/I− redox reaction, lower charge transfer resistance on the electrolyte/electrode interface for I3−/I− redox reaction than that of Pt electrode, which is due to that the synergistic effect combined platinum nanoparticles with graphene nanosheet intrinsic characteristic. As a result, the DSSC based on the PtNP/GN counter electrode achieved a high power conversion efficiency of 7.88% under AM1.5 illumination of 100mWcm−2, which is higher 21.04% than that of the DSSC based on Pt electrode.

Electrochemical deposition and characterization of CuGa xS yO z alloy thin films

Abstarct CuGaxSyOz alloy thin films are fabricated onto fluorine-doped-tin-oxide-coated glass by one step electrochemical deposition from an aqueous solution. The films were deposited at six different Cu–Ga ratios in the solution, i.e., Cu/Ga=3/2, 1/1, 1/2, 1/4, 1/12 and 1/30. The impact of the Cu/Ga ratio on composition, surface morphology, photosensitivity and optical transmission of the films were investigated. We successfully deposited both the Cu-rich and Ga-rich thin films. The deposited films have band gap energy of 1.5–2.8 eV depending on the Cu/Ga ratio. Photoelectrochemical measurement confirms that deposited films are mainly p-type except for the film deposited with Cu/Ga=1/30 which behaved as a nearly intrinsic semiconductor.

The crystallisation of Cu 2ZnSnS 4 thin film solar cell absorbers from co-electroplated Cu–Zn–Sn precursors

The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu 2ZnSnS 4 based thin film solar cells. A kesterite based solar cell (size 0.5 cm 2) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu–Zn–Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu 2SnS 3 and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu 3Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu 6Sn 5 and Sn phases were detected. The formation mechanism of Cu 2SnS 3 involves the binary sulphides Cu 2 − x S and SnS 2 in the absence of the binary precursor phase Cu 6Sn 5. The presence of Cu 6Sn 5 leads to a preferred formation of Cu 2SnS 3 via the reaction educts Cu 2 − x S and SnS 2 in the presence of a SnS 2(Cu 4SnS 6) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase.