Low-cost Electrodeposition Technique Research Articles

Effect of annealing temperature on physical properties and photoelectrochemical behavior of electrodeposited nanostructured NiO thin films for optoelectronic applications

Our paper used a low-cost electrodeposition technique to grow Nickel Oxide (NiO) thin films on fluorine-doped tin oxide (FTO) substrate. As-deposited films were annealed at different temperatures (350, 400, 450, and 500 °C). X-ray diffraction (XRD), Raman spectroscopy (RAM), scanning electron microscopy (SEM), UV–vis spectrophotometer, photoluminescence (PL), Cyclic voltammetry (CV), photocurrent (PC), electrochemical impedance spectroscopy (EIS), and Mott-Schottky analysis (MS) were used to study and investigate the effect of annealing temperatures on the structural, morphological, electrical, and optical properties of prepared thin films. XRD patterns proved the cubic phase of all NiO samples with the preferential orientation in (111) direction. SEM results showed that the grain size increased with increasing annealing temperature. The optical transmission was studied by a UV–vis spectrophotometer, where high transmittance for NiO thin films was found to vary in the range of 73–84 % in the visible wavelength region, depending on the annealing temperatures. At the same time, UV–visible measurements indicate an absorption band edge at 311 nm, mainly recognized as a characteristic direct band gap for prepared NiO. The optical gap calculated from the Tauc relation showed a decreasing trend from 3.97 to 3.86 eV with increasing annealing temperature from 300 °C to 500 °C. PL spectra of synthesized samples revealed two distinct emission peaks at around 400 nm and 490 nm. RAM analysis confirmed the presence of three characteristic peaks related to the vibration of Ni–O bonds. The NiO film annealed at 500 °C displays the highest specific capacitance value by CV analysis. The P-type conductivity of manufactured arrays and enhanced electrical properties were confirmed by PC, EIS, and MS analysis. The highest carrier concentration values (9.19 × 1018 cm−3) and flat band potential (0.82 V) were obtained for samples annealed at 500 °C. Our outcomes proved that NiO-500 °C thin films are ideal candidates for optoelectronic applications.

Correction: Structural, Morphological and Optical Properties of Cu2MSnS4 (M = Cu0.5Ni0.5) Synthesized by a Simple and Low Cost Electrodeposition Technique

Correction: Structural, Morphological and Optical Properties of Cu2MSnS4 (M = Cu0.5Ni0.5) Synthesized by a Simple and Low Cost Electrodeposition Technique

Structural, Morphological and Optical Properties of Cu2MSnS4 (M = Cu0.5Ni0.5) Synthesized by a Simple and Low Cost Electrodeposition Technique

Structural, Morphological and Optical Properties of Cu2MSnS4 (M = Cu0.5Ni0.5) Synthesized by a Simple and Low Cost Electrodeposition Technique

Improvement of physical and electrochemical properties of Cu2O thin films with Fe ions doping towards optoelectronic applications

Pure and doped Cu2O thin films were deposited on FTO substrate with various Fe dopant concentrations employing low-cost electrodeposition technique. All thin films were successfully characterized employing XRD, SEM, PL spectroscopy, UV–vis spectrophotometer, and photocurrent measurement. XRD results indicate the formation of cubic structure of thin films where all grown grains were well oriented along (111) diffraction plane at different dopant concentrations. The crystal size of doped Cu2O thin films was calculated from the Scherrer equation were the values range from 24.95 to 31.75 nm. The creation of grains similar pyramid-shaped for grown thin films is proven by SEM results. PL results reveal the characteristic emission peaks of Cu2O thin films at 521 and 704 nm which are attributed to the inter-band transitions and Cu vacancies or O interstitial, respectively. Moreover, PL intensity changed with doping process due to the integration of Fe3+ ions in interstitial positions or/and Cu sites. The optical measurements indicate that thin films have optical absorption edge which located between 490 and 550 nm that attributed to Cu2O band gap. The estimated Eg for pure and doped Cu2O thin films was founded to be in the range from 2.1 to 2.59 eV. The photocurrent measurements signal that electrodeposited Cu2O films are p-type semiconductors. Furthermore, the doping process enhancement the photocurrent where more visible light could be more captured and therefore improvement of electron-hole production. The results show that Fe doped Cu2O thin films are talented candidate for the optoelectronic applications such as sensors and solar cells.

Heusler compound [formula omitted]FeGa nanoarchitectures

Heusler type one-dimensional nanogeometries Ni2FeGa have been fabricated in the nanopores of 150 nm AAO (Anodic Aluminium Oxide) templates using simple and low-cost electrodeposition technique at room temperature. The structure of prepared nanoarchitectures is face centered cubic (fcc) with a secondary γ phase. Magnetic properties have been studied at room temperature as well as at low temperatures. It has been found that saturation magnetization MS decreases as temperature rise up. The nanowires have maintained ferromagnetic behavior from 5 K to 350 K. The Ni2FeGa nanowires (NWs) and nanotubes (NTs) have the same saturation magnetization, the difference of the resonance field Hr is mainly attributed to the difference of the anisotropy field Hk under the fixed microwave frequency. Hr for the NT sample is smaller than that for the NW sample.

Influence of potential on structural, compositional, optical and magnetic properties of electrochemically grown iron selenide thin films

For the last few years iron chalcogenides in industries received attention due to its salient features such as structure, band gap, physical, chemical and magnetic properties. The main objective of the present investigation is to identify the modified features of iron selenide thin film growth by simple, low cost electrodeposition technique. Thin films of iron selenide are deposited on Tin Oxide coated conducting glass substrates. Structural features reported that the prepared films found to exhibit hexagonal structure with orientation along (002) plane. The parameters such as crystallite size, rms microstrain, dislocation density and stacking fault probability are determined for the deposited films. Scanning electron microscopic images showed that the deposited films have well defined morphology with nearly stoichiometry. The deposited films have band gap value around 1.21 eV. Magnetic properties are determined using Vibrating Sample Magnetometer and the parameters such as coercivity, retentivity and saturation magnetization are estimated. The experimental observations are discussed in detail.

Co-based full heusler alloy nanowires: Modulation of static and dynamic properties through deposition parameters

In this work, a successful fabrication of Co2MnAl heusler alloy nanowires in anodic alumina templates has been demonstrated using simple and low-cost electro-deposition technique at room temperature. The role of deposition parameters, such as pH of the electrolyte solution were investigated on the structural and magnetic properties of Co2MnAl nanowires. It is observed that the crystallinity improves with the increase of pH of the solution till around pH=3.0 where the best crystallinity is achieved. The X-Ray diffraction pattern confirms the formation of B2 crystal type in the Co2MnAl heusler alloys which is further verified by high-resolution transmission electron microscope images. The static magnetic properties were explored by the VSM analysis which revealed that the saturation magnetization, squareness, coercivity and uniaxial anisotropy of the nanowires increase with the increase in pH value. The highest remanent squareness of 76% is observed for pH=2.9. The dynamic measurements of heusler alloy nanowires have been studied by ferromagnetic resonance technique using the flip-chip method in the field-sweep mode at different applied frequencies ranging from 20-40 GHz. It is observed that the resonance field increases linearly with the increase in frequency for all samples. Further, the resonance field decreases up to 35% with the increase of pH value of electrolyte, resulting in an increase in the effective field.

Hydrogen ion sensing characteristics of Na3BiO4–Bi2O3 mixed oxide nanostructures based EGFET pH sensor

In the present paper, Na3BiO4–Bi2O3 films have been tested for hydrogen ion sensing. Na3BiO4–Bi2O3 mixed oxide nanostructures were deposited on the Indium–Tin-Oxide (ITO) coated glass substrate using a low-cost electrodeposition technique at room temperature. The nanostructures have been characterized using FESEM and XPS to study their morphology and composition, respectively. Vertically aligned nanostructures (thickness~90 nm) with well-defined edges were seen in FESEM studies. XPS analysis indicates the presence of Na3BiO4 and Bi2O3. The crystallinity and the mixed phase of the film were further confirmed by X-ray diffraction study. These nanostructures were explored as a potential candidate for pH sensing using them as a sensing film for Extended-Gate Field-Effect Transistor (EGFET). A sensitivity of 49.63 mV/pH has been observed with good linearity. To the best of our knowledge, for the first time vertically aligned Na3BiO4–Bi2O3 mixed oxide nanostructures are demonstrated as an EGFET-based (Hydrogen ion) pH sensor.

Anode electrodeposition of 3D mesoporous Fe2O3 nanosheets on carbon fabric for flexible solid-state asymmetric supercapacitor

Novel nanostructured Fe2O3 with a network of 3D mesoporous nanosheets was synthesized by depositing on carbon fabric (Fe2O3@CF) for use as an anode using a potentially low-cost electrodeposition technique. The electrode with freestanding binder-free Fe2O3@CF of high surface area displayed an exceptional specific capacitance of 394.2 F g−1. Moreover, a flexible solid-state asymmetric supercapacitor (ASC) was fabricated with a negative electrode based on Fe2O3@CF and a positive electrode based on MnO2@CF in the presence of PVA-LiCl as gel electrolyte. The above ASC exhibited a high operating potential up to 1.8 V, a favorable specific capacitance of 93.5 F g−1 (2.92 F cm−3), long-term stability (91.3% retention of initial value over 5000 cycles), and remarkable mechanical stability and flexibility, suggesting its potential application for wearable electronics.

Studies on the graded band-gap copper indium di-selenide thin film solar cells prepared by electrochemical route

A graded band-gap CuInSe2 (CIS) thin film solar cell (TFSC) having glass/FTO/CdS/CIS multilayer/Au structure has been fabricated. A simple and low-cost electrodeposition technique is used to deposit the multilayers of CIS onto fluorine doped tin oxide (FTO) coated glass substrate. A conventional three-electrode geometry consisting, FTO, graphite and Ag/AgCl as a working, counter and reference electrodes, respectively was used for electrodeposition. Structural characterization was carried out using X-ray diffraction (XRD) and Raman spectroscopy, which revealed the chalcopyrite tetragonal CIS structure with a quite Cu-rich surface which reduces upon selenization. The morphology of the as grown and selenized CIS multilayer thin films was studied by using atomic force microscopy (AFM) which shows the compact and uniform layer formation. The depth profile distribution of individual elements in both as-grown and selenized CIS multilayer thin films has been determined using secondary ion mass spectroscopy (SIMS). SIMS results revealed that the proposed graded band gap structure is retained even after selenization. The presence of Cu+, In3+ and Se2− oxidation states were confirmed using X-ray photoelectron spectroscopy (XPS). A single layer and multilayer CIS solar cell devices yielded ∼5.10% and ∼7.20% power conversion efficiency, respectively. In the present work, pH 3 buffer solution helps to improve the morphology of CIS layer which gives the better power conversion efficiency as compared to the previously reported value.

Direct electrochemical growth of amorphous molybdenum sulfide nanosheets on Ni foam for high-performance supercapacitors

Crystalline molybdenum sulfides (MoSx) have gained much attention as electrode materials for supercapacitors due to their specific atomic structure and high theoretical specific capacitance. However, poor electric conductivity and few accessible active sites as well as strictly controlled synthetic processes limit their capacitive performances. In this work, amorphous MoSx (a-MoSx) nanosheets with porous structure was directly grown on Ni foam by a simple and low-cost electrodeposition technique. By using a-MoSx/Ni foam directly as the electrode material for supercapacitor, a high specific capacitance of 463 F/g was achieved at 1 A/g with good cycling stability at high rate. The isotropic and porous natures as well as ion reservoir function of the amorphous phase offers abundant active sites, transportation channels for ions and large electrode/electrolyte contact area, ensuring facile electrolyte diffusion within the active material. The strong adhesive of electrodeposited material to the underlying Ni foam substrate constructs an effective electron transport channel during the charging and discharging process. This work highlights the importance of electrodeposited amorphous MoSx for potential application in supercapacitors.

Inexpensive Cu2SnS3 grown by room-temperature aqueous bath electrodeposition for thin film solar cells

We report the growth of Cu2SnS3 (CTS) thin films on F-doped SnO2 (FTO) glass substrates at room-temperature by low-cost electrodeposition technique using an aqueous medium without the evolution of hydrogen. Electrolyte concentration and deposition potential were optimized under the limits of water hydrolysis. As-deposited films are post-annealed in the presence of the sulphur flakes to establish the stoichiometry. The annealed films were found to contain high phase purity and favorable optical properties to be useful for the photovoltaic applications. Optical data reveal that the CTS films have direct optical bandgap of 1.25 eV with an absorption coefficient of the order of 104 cm[Formula: see text]. A photovoltaic cell architecture of Glass/FTO (back contact)/CTS/CdS/Al:ZnO/Al (front contact) exhibited an open circuit voltage of 28 mV, a short circuit current density of 8.4 [Formula: see text]A/cm2 and the fill factor of 25%. The absorber thickness optimization and the use of Mo-coated glass as a back contact improve the solar cell parameters. A further study in this aspect is under way.

Performance of titanium–nickel (Ti/Ni) and graphite felt-nickel (GF/Ni) electrodeposited by Ni as alternative cathodes for microbial fuel cells

Abstract Electrodes are important components of bioelectrochemical systems (BESs), such as the microbial fuel cells (MFCs). The low-cost cathodes of titanium–nickel (Ti/Ni) and graphite felt-nickel (GF/Ni) are important to be evaluated as cathodes for MFCs. In this study, Ni particles are deposited onto the Ti and GF surface using a simple and low-cost electrodeposition technique. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyse the cathode surfaces. The electrodeposition of Ni onto GF appears more uniform without significant agglomeration compared with that onto Ti. This uniform deposition is perhaps the reason for a higher maximum power density (Pmax), lower internal resistance (Rin) and higher Columbic efficiency (CE) for MFC with GF/Ni cathode (113.4 ± 0.6 mW/m2, 1264.4 Ω and 29.6%, respectively) than those measured with Ti/Ni cathode (110.7 ± 8.0 mW/m2, 3375.8 Ω and 23.7%, respectively). However, the performance of these cathodes remains lower compared with the GF/Pt cathode (140.0 mW/m2, 845.7 Ω and 42.0%, respectively). Based on the preparation technique, material cost and performance, both Ti/Ni and GF/Ni cathodes can be considered as alternative to Pt catalyst for MFC application.

Controllable growth of ZnO nanorods via electrodeposition technique: towards UV photo-detection

An electro-chemical approach for controlled growth of seedless ZnO nanorods was investigated. Field emission scanning electron microscopy confirms ZnO nanorod morphology can be controlled by varying the electrodeposition duration. Increased growth time enhances the crystallinity of ZnO nanorods and releases the strain on ZnO nanorods, as revealed by x-ray diffraction analysis. A significant change in the near band gap and the defect level luminescence were observed for different growth time ZnO nanorods. The variation in zone-centre E2 (high) optical phonon mode of ZnO nanorods was studied using micro-Raman measurements. The I–V characteristics of the ZnO nanorods potentially enable applications in UV photodetection even at very low voltage range. Photodetectors based on ZnO nanorods have a faster response time (~29 s) and exhibited high photosensitivity, approximately 28 at 1 V forward bias, as compared to recent reported values. The results obtained are exciting in view of using a low cost electrodeposition technique at low temperature for achieving high-quality electrodeposited ZnO nanorods and its possible use in optoelectronic devices.

Communication—High Performance Schottky Diodes on Flexible Substrates Using ZnO Electrodeposited on Cu

We report the fabrication of Cu/ZnO Schottky diodes on flexible polyimide substrates that can retain high performance under substrate bending. The ZnO films are synthesized with an optimized low-cost electrodeposition technique on a thin copper (Cu) film adhered to a flexible Kapton substrate via a titanium (Ti) adhesion layer. The Cu/ZnO system constituted a Schottky diode that demonstrated rectification ratios of ∼106 and ideality factors of ∼2 to 3, which surpass the current state-of-the-art for solution-processed ZnO films.

Crystallinity improvement of ZnO nanorods by optimization of low-cost electrodeposition technique

Extremely low-cost electrodeposition technique was developed to deposit ZnO nanorods. The growth process was performed using standard DC power supply, milliammeter and two-electrode electrochemical cell. The deposition was carried out on indium tin oxide (ITO) coated glass substrates by changing deposition parameters such as cathodic deposition current and time, solution molarity and temperature. The parameters varied to obtain optimum transparent semiconductor material for optoelectronic applications. Structural characterizations by X-ray diffraction (XRD) indicate the formation of polycrystalline phase ZnO with strong c-axis orientation and were sensitive to deposition temperatures and molarity as well. Average optical transmittance for the best two ZnO nanorod series was around 60% and 42%, respectively. The optical energy band gap of the ZnO nanorods decreased from 3.24eV to 3.21eV as the deposition time increased. All the nanorods were n-type with a high carrier concentration of 1×1020cm−3 and low 1–2×10−3Ωcm resistivity.

Synthesis and magnetic characterization of a Cu80Co20 thin film obtained by electrodeposition technique

A granular Cu80Co20 alloy was elaborated by a low cost electrodeposition technique consisting in reducing simultaneously the Cu2+ and Co2+ ions onto a silicon substrate. The deposition parameters were determined from current-potential curves. The structure of the film was characterized down to the atomic scale by transmission electron microscopy and atom probe tomography. The results show that the as-deposited Cu80Co20 thin film consists mainly of a paramagnetic Cu–Co solid solution containing 10–30% of Co, in which pure Co superparamagnetic nanoparticles are dissolved. Annealing at 500°C for 1h leads to the decomposition of the Cu–Co solid solution into purified Cu matrix containing ferromagnetic Co-rich precipitates. The magnetoresistance effect decreases after the heat treatment, in relation with the disappearance of the superparamagnetic Co nanoparticles upon annealing.

Structural characterization of electrodeposited EuSe thin films

A simple and low-cost electrodeposition technique is used to investigate the codepostion of EuSe from aqueous acidic solutions containing europium and selenium ions on stainless steel cathodes. The europium ions are complexed with disodium ethelenediaminetetraacetic acid (Na 2-EDTA). The preparative parameters such as deposition potential, deposition time, bath temperature, pH, etc., are optimized to obtain good-quality electrodeposits. The optimized preparative parameters are: deposition potential −560 mV versus SCE, deposition time 75 min, bath temperature 70°C, electrolyte bath [(0.01 M EuCl 2 + 0.05 M Na 2-EDTA) + 0.001 M SeO 2] in 1:1 volumetric proportions at pH 4.0 The electrodeposits were bluish brown and about 1 to 2 μm thick. The EuSe films characterized by XRD studies reveal that films are polycrystalline with intense peaks along the planes (111) and (200). The ratio of complexant concentration to the metal ion concentration is 5, and is found sufficient for the material formation. SEM studies show a cauliflower-like morphology of EuSe fully covering the stainless steel substrates. The EDAX analysis shows that the EuSe electrodeposit is rich in selenium. The magnetic studies of the material reveal that the prepared films are magnetic in nature.