Electrodeposited Precursors Research Articles

Electroreduction of Si(NCO)4 for Electrodeposition of Si

The electrochemical reduction and concomitant suitability of tetraisocyanatosilane, Si(NCO)4, as a precursor for Si electrodeposition has been examined. At T = 25 °C, voltammetric data indicated that the electroreductive pathway of Si(NCO)4 paralleled the electroreduction of SiCl4, albeit with attenuated current densities. At T = 150 °C, the measured current density increased significantly due to coupled reaction likely involving an electropolymerization of the tetraisocyanato ligand. At either temperature, the electrochemical response of Si(NCO)4 did not strongly depend upon the identity of the anion in the supporting electrolyte. A combination of chronoamperometric, electron microscopy, and X-ray photoelectron spectroscopy data were used to study the morphology and composition of the electrodeposited Si films at room temperature. The composition and morphology of the as-electrodeposited films were consistent with the formation of amorphous Si when using solid n +-Si electrodes, similar to what is observed during the electroreduction of SiCl4. Attempts to use Si(NCO)4 for Si crystal growth by the electrochemical liquid-liquid-solid (ec-LLS) process with a liquid e-GaIn electrode resulted in no appreciable crystalline Si product. Although Si(NCO)4 can be used for electrodeposition of amorphous Si onto solid electrodes at room temperature, more work is needed to identify conditions that would facilitate its use for ec-LLS.

Preparation of layered double hydroxide films using an electrodeposition and subsequent crystal growth method

AbstractThe surface coating of a gas reaction electrode with layered double hydroxides (LDHs) featuring various electrode catalyst activities was prepared via electrodeposition and the subsequent crystal growth of LDHs. LDH formation was confirmed by X-ray diffraction and Raman scattering measurements after subsequent crystal growth on respective electrodeposited precursor films in Ni-Fe and Zn-Al LDH systems. However, the crystal growth of LDHs in Ni-Mn and Cu-Mn systems was observed on the Mg-Al LDH-electrodeposited films. LDH films were also deposited on the surface of a carbon paper electrode with a rugged surface via electrodeposition and subsequent crystal growth. Using the prepared LDH-coated carbon paper electrodes, the electrode catalytic activity for the oxygen reduction reaction (ORR) was examined. For Ni-Mn, Ni-Al and Ni-Fe LDH-coated carbon paper electrodes, the threshold voltages of the ORR decreased. Hence, the LDHs electrodeposited on a gas reaction electrode have high electrochemical catalytic activity for the ORR.

Influence of co-electrodeposition parameters in the synthesis of kesterite thin films for photovoltaic

Abstract Electrodeposition is one of the most attractive techniques for the synthesis of thin films chalcogenides for photovoltaic applications, in particular for earth abundant kesterite. In this work, the influence of core parameters of this technique, such as the applied potential and deposition time, on the chemical composition of co-deposited Cu–Zn–Sn precursors is studied. Indeed, how the precursor composition affects the final composition of Cu2ZnSnSe4 after reactive annealing in Se atmosphere is also investigated, not only at the film level but also in solar cell devices. X-ray based techniques (XRF and XRD) reveal that the chemical and phase composition of electrodeposited precursors is highly sensitive to small modifications (25 mV) of the applied potential during electrodeposition. Only when the applied potential is −1.2 V (vs. Ag/AgCl) the precursor composition matches to what is required for operating devices. Multi-wavelength Raman spectroscopy of selenized precursors confirms that lower potential than −1.2 V favor the formation of Sn-rich secondary and ternary compounds after selenization, while a higher overpotential led to the formation of ZnSe in the film. On the other hand, the use of longer deposition times enhance the incorporation of zinc in the film, modifies the morphology of the precursor and promotes the formation ZnSe after selenization. Photovoltaic devices were only obtained at an electrodeposition potential of −1.2 V, and reaching a maximum efficiency close to 5% for a 10 min electrodeposited CZT precursor.

An electrochemical strategy to fabricate MnOx thin film from spent batteries for pseudocapacitive applications

This paper details a sustainable procedure to fabricate MnOx thin film electrode with enhanced pseudocapacitance property from end-of-life batteries. Manganese (Mn) in form of metal was thermally isolated from spent batteries and then used as a precursor for electrodeposition. MnOx was electrodeposited on an ITO current collector at ambient temperature using cyclic voltammetery (CV) at potential in the range between −1.5 V and 1.5 V vs. SCE at a scan rate of 50 mV s−1. At potential of −1.2 V, Mn was deposited in metallic form on the surface of ITO which then converted to MnOx. The initial deposition of Mn acted as a surface modifier which significantly improved the adherence of MnOx thin film to the surface of ITO. The physicochemical properties of the as-prepared manganese oxide thin film were examined using HR-XPS, FE-SEM, HR-TEM, and TOF-SIMS. From TEM and SIMS analysis, the thickness of the film was revealed to be between 110 and 120 nm. XPS analysis also indicated that oxidation state of Mn across the depth of the film was a combination of (III) and (IV), which intensify the electron transfer capabilities. The electrochemical performance of MnOx thin film as a supercapacitor was also comprehensively investigated. The result showed that the MnOx thin film exhibited an enhanced specific capacitance of 411 F g−1 (at 1 mV s−1) with a retention rate of 92% after 2500 cycles. The outcome of this paper can be potentially used to help to tackle the problem associated with the tremendous growth in the demand for the metals used in fabrication of energy storage devices while simultaneously help in recovery of valuable metals embedded within end-of-life batteries.

Synthetic methodology for preparation of dinitrosyl iron complexes.

After the first structural characterization of dinuclear dinitrosyl iron complex (DNIC) in 1958 and discovery of natural dinitrosyl iron unit (DNIU) [Fe(NO)2] in 1964-1965, continued investigations on natural and synthetic DNICs explored their ubiquitous functions as (1) a product for nitrosylation of non-heme Fe proteins and chelatable iron pool, (2) a biological vehicle for iron and nitric oxide, (3) a novel redox-active unit for stabilization and activation of small molecules, (4) an electrocatalyst for water splitting, and (5) a precursor for electrodeposition of Fe-containing hybrid material. From a synthetic chemistry perspective, herein, we summarize four synthetic methodologies for preparation of structure-characterized DNICs in the attempt to attract continued development of unexplored DNICs featuring novel functions. As collected from CCDC database, structure-characterized DNICs can be classified into (1) tetrahedral {Fe(NO)2}9 DNICs with C/N/P/O/S/Se/Cl/Br/I ligation modes, (2) five-/six-coordinate {Fe(NO)2}9 DNICs with N/O ligation modes, (3) tetrahedral {Fe(NO)2}10 DNICs with C/Sn/N/P/O/S/H ligation modes, (4) metallothiolate-bound {Fe(NO)2}9/{Fe(NO)2}10 DNICs, and (5) dinuclear {Fe(NO)2}9-{Fe(NO)2}9, {Fe(NO)2}9-{Fe(NO)2}10, and {Fe(NO)2}10-{Fe(NO)2}10 DNICs with thiolate/alkoxide/pyrazolate/CO bridging ligands. After buildup of the DNIU [Fe(NO)2] using NO, NO+, and NO2- as alternative sources of nitrosyl ligands, ligand substitution and modification reaction of DNICs, redox interconversion between {Fe(NO)2}9 and {Fe(NO)2}10 cores, and transformation between mononuclear and dinuclear DNICs establish the comprehensive pathways to bridge alternative types of DNICs in the chemical library of structure-characterized DNICs. This review on the synthetic methodology for preparation of DNICs will facilitate the incorporation of DNIU [Fe(NO)2] into (bio)materials for potential applications of DNICs in chemistry, catalysis, biology, and biomedicine.

Cu(In,Ga)Se2 absorbers prepared by electrodeposition for low-cost thin-film solar cells

Reducing the manufacturing cost of solar cells is necessary to their industrial production. Electrodepositing is an effective, non-vacuum method which is very suitable for cutting the manufacturing cost of thin films as well as developing its large-scale industrial production. In this study, about 1-μm-thick Cu(In,Ga)Se2 (CIGS) precursors were electrodeposited on Mo/glass substrates in aqueous solution utilizing a three-electrode potentiostatic system. Triethanolamine was used as complexing agent, and all parameters of electrodeposition were precisely controlled. After that, the electrodeposited precursors were selenized in a Se atmosphere with different heating ramp rates (60 and 600 °C·min−1). High-quality CIGS films were obtained, and their characteristics were investigated by X-ray fluorescence, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, Raman spectra and near-infrared–visible (NIR-Vis) spectra. The results reveal that there are many differences between the properties of the films under different heating rates. Finally, CIGS solar cells were fabricated using a fast and a slow heating rate. The maximum efficiencies achieved for the films selenized at 60 and 600 °C·min−1 are 3.15% and 0.71%, respectively.

Chemical deposition of selenium layers for selenization of sputtered and electrodeposited Cu–Zn–Sn metallic layers for photovoltaic application

One of the key steps for high efficiency kesterite based solar cells is the control of the growth conditions of the kesterite phase from precursors. In this work, chemical deposition was used to introduce the selenium needed for Cu–Zn–Sn selenization and Cu2ZnSnSe4 (CZTSe) synthesis. The influence of annealing time and precursor morphology based on deposition techniques (electrodeposition or sputtering) on the reaction path and kinetics of growth and degradation of kesterite phase was studied using scanning electron microscopy, X-ray diffraction and Raman characterizations. Important differences were detected between porous electrodeposited precursors and dense sputtered precursors. It was suggested that this difference comes from the morphology of the precursors, and that a control of the morphology is critical for the control of the annealing processes in CZTSe synthesis.

3.6%-CZTSS Device Fabricated From Ionic Liquid Electrodeposited Sn Layer

Cu/Sn/Zn stacked layers were electrodeposited and subsequently annealed in a tube furnace in elemental sulfur and selenium at 570oC. Cyclic voltammogram of Sn-salt in ionic liquid was recorded. Thin films were characterized by inductively coupled plasma-mass spectrometry (ICP-MS), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). The device was characterized by current-voltage (I-V) and quantum efficiency (QE). The device fabricated using electrodeposited precursor film resulted in efficiencies of 3.6%.

Nickel Cysteine Complexes as Anodic Electrocatalysts for Fuel Cells

Compared to platinum, nickel is an inexpensive catalyst that can oxidize methanol in alkaline media. There is a desire to increase nickel loading during electrodeposition for improved performance. In this paper, a nickel cysteine complex (NiCys) is used as the precursor for electrodeposition on glassy carbon electrode surfaces. After optimization of cysteine concentration, the surface concentration of NiOOH on NiCys electrodes characterized by cyclic voltammetry in 0.1 M NaOH can reach 1.28 (± 0.32) × 10−7 mol/cm2. The large amount of NiOOH on NiCys electrodes provide 5 times the methanol oxidation current compared to Ni electrodes prepared without cysteine as demonstrated by chronoamperometry at 0.7 V vs. Hg/HgO. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy have been applied to examine surface morphologies and structures of NiCys and Ni electrodes. The analysis reveals that cysteine adjusts the solubility of Ni(OH)2 in 0.1 M NaOH, so more uniform and smaller size nanoparticles are electrodeposited on electrode surfaces compared to Ni electrodes.

Sulfurization of Cu–In electrodeposited precursors for CuInS 2-based solar cells

Cu–In electrodeposited layers were annealed using rapid thermal processing (RTP) in a reactive atmosphere containing sulfur vapors. The CuInS 2 formation mechanism during sulfurization of electrodeposited precursors proceeds mainly through direct sulfurization of the metallic Cu–In alloy, forming spinel CuIn 5S 8 and chalcopyrite CuInS 2 ternary phases. During the heating step, the Cu–In metallic alloy gets richer in copper as the temperature increases and transforms from CuIn 2 to Cu 11In 9, then Cu 16In 9 and finally to Cu 7In 3. The use of rapidly cooled samples stopped after different durations of the process along with ex-situ XRD analysis enabled us to differentiate the Cu 16In 9 and Cu 7In 3 phases. Finally, the efficiency of the solar cells made with the two-step electrodeposition and RTP low-cost process reaches 11% (active area 0.421 cm 2), which is close to the results obtained for cells made with PVD precursors.

Properties of CuIn xGa 1−xSe 2 thin films grown from electrodeposited precursors with different levels of selenium content

In this paper, polycrystalline CuIn x Ga 1− x Se 2 (CIGS) thin film absorbers were prepared by selenizing electrodeposited (ED) precursors with two different levels of selenium content: rich in selenium and poor in selenium. Comparing the results obtained by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and illuminated current–voltage ( J– V), it was found that absorber layers processed from Se-poor ED precursors shows better crystalline quality and increased gallium incorporation, which thus improved cell performance, compared to the layers grown using Se-rich ED precursors. The best cell fabricated from Se-poor ED precursor shows a conversion efficiency of 1.63% at AM1.5 global light.

P-type CuInSe2 thin films prepared by selenization of one-step electrodeposited precursors

In this study, p-type CuInSe2 (CIS) films were prepared by selenization of one-step electrodeposited Cu-In-2Se (atomic ratio) precursors. To obtain high-quality, dense, and homogeneous CIS films for solar cell application, the effects of substrate temperatures during selenization and precursor compositions on the final microstructures were systematically investigated. The precursor layers evolved in very different ways under different selenization conditions. The final microstructures and phases of the films depended critically on the precursor compositions, selenization temperature, and the selenization thermal process history. Low melting temperature CuxSe phase, which tended to segregate at the film surface, can efficiently assist the CIS grain growth. Large hexagonal CuSe platelets were formed at a temperature as low as 170 °C in Cu-rich precursor, which acted as an element-transport flux agent at higher temperature under high Se vapor and reacted with In-Se selenide to form CIS at temperatures above 500 °C. Good crystalline quality chalcopyrite CIS film was obtained at a selenization temperature of 550 °C.

Preparation and properties of CuInxGa1−xSe2 thin-film solar cell absorbers from selenization of Ga-rich electrodeposited precursors

This paper presents our studies on the preparation and properties of CuInxGa1−xSe2 (CIGS) thin-film solar cell absorbers grown from Ga-rich electrodeposited precursors followed by their selenization. X-ray fluorescence and scanning electron microscopy results show that the deposition potential of −0.7 V is suitable for obtaining a smooth CIGS precursor film with inclusion of more gallium (x = 0.4). X-ray diffraction studies reveal that a stoichiometric CuIn0.7Ga0.3Se2 phase that can be formed by selenization of the Ga-rich precursor is ascribed to a high Se vapor pressure. An optical study shows that the band-gap energy of the stoichiometric CIGS sample is 1.17 eV. The best photovoltaic devices showed a conversion efficiency of 2.0 ± 0.5%.

Preparation of Cu2ZnSnS4 thin films by sulfurization of co‐electroplated Cu‐Zn‐Sn precursors

AbstractCu2ZnSnS4 (CZTS) thin films were prepared by sulfurization of electrodeposited Cu‐Zn‐Sn precursors. The Cu‐Zn‐Sn precursors were deposited on Mo‐coated glass substrates in a one‐step process from an electrolyte containing copper (II) sulfate pentahydrate, zinc sulfate heptahydrate, tin (II) chloride dehydrate and tri‐sodium citrate dehydrate. The precursors were sulfurized by annealing with sulfur at temperatures of 580 °C and 600 °C in an N2 atmosphere. X‐ray diffraction peaks attributable to CZTS were detected in the sulfurized films. Photovoltaic cells with the structure glass/Mo/CZTS/ CdS/ZnO:Al/Al were fabricated using the CZTS films by sulfurizing the electrodeposited precursors. The best photovoltaic cell performance was obtained with Zn‐rich samples. An open‐circuit voltage of 540 mV, a short‐circuit current of 12.6 mA/cm2 and an efficiency of 3.16% were achieved. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Raman microprobe characterization of electrodeposited S-rich CuIn(S,Se)2 for photovoltaic applications: Microstructural analysis

This article reports a detailed Raman scattering and microstructural characterization of S-rich CuIn(S,Se)2 absorbers produced by electrodeposition of nanocrystalline CuInSe2 precursors and subsequent reactive annealing under sulfurizing conditions. Surface and in-depth resolved Raman microprobe measurements have been correlated with the analysis of the layers by optical and scanning electron microscopy, x-ray diffraction, and in-depth Auger electron spectroscopy. This has allowed corroboration of the high crystalline quality of the sulfurized layers. The sulfurizing conditions used also lead to the formation of a relatively thick MoS2 intermediate layer between the absorber and the Mo back contact. The analysis of the absorbers has also allowed identification of the presence of In-rich secondary phases, which are likely related to the coexistence in the electrodeposited precursors of ordered vacancy compound domains with the main chalcopyrite phase, in spite of the Cu-rich conditions used in the growth. This points out the higher complexity of the electrodeposition and sulfurization processes in relation to those based in vacuum deposition techniques.

Electro-deposition of Tl-1223 coated conductors using potential cycling and step methods

In the present study, cyclic and step potential were applied for the electro-deposition, and their effects on chemical composition and surface morphology of the electro-deposited Tl-1223 precursor film were investigated. Cyclic voltammetry resulted in more uniform morphology and homogeneous distribution of composition, provided that proper initiation voltage and potential sweep rate are chosen. Furthermore, the cyclic voltammetry was likely to much facilitate the control of the deposition parameters to obtain an aimed chemical composition.

YBa 2Cu 3O 7− δ tapes synthesised on untextured silver substrates by an electrodeposition process

We have investigated the possibility of preparing YBa 2Cu 3O 7− δ tapes by an electrodeposition process. Films of different thickness (1.5 and 0.5 μm) have been prepared on both sides of untextured silver substrates by alternating sequential electrodeposition of copper, yttrium and barium and oxidation–reduction annealing. A final heat treatment permits the transformation of the electrodeposited precursors into the superconducting phase. Critical temperatures as high as 92 K and transport critical current densities of 14 000 A/cm 2 at 77 K under self-magnetic field are currently achieved. The influence of the superconducting layer thickness on the performances as well as the limitations in the current path are discussed.

Characterization and stability of hydroxyapatite coatings prepared by an electrodeposition and alkaline-treatment process.

Hydroxyapatite (HA) coatings on titanium alloy substrates were prepared by an alkaline treatment of electrodeposited precursors. The structure, residual stress, and bond strength of the coatings were investigated. Test results showed that the coatings processed in this study exhibited fairly low tensile residual stress, high crystallinity, and were free of an amorphous phase. The bond strength of the coatings increased with the decrease of current density in the range of 0.2-15 mA/cm(2), and reached 14 MPa at 0.2 mA/cm(2). Evaluation of the coatings was performed together with the evaluation of the plasma-sprayed HA coatings immersed in distilled water. It was revealed that the dissolution and bond strength degradation of the coatings were much lower than those of the plasma-sprayed HA coatings.

A 10% Cu ( In , Ga ) Se2 Based Photovoltaic Structure Formed by Electrodeposition and Subsequent Thermal Processing

(CIGS) thin films were formed from an electrodeposited (CIS) precursor by thermal processing in vacuum in which the film stoichiometry was adjusted by adding In, Ga, and Se. The structure, composition, morphology and opto‐electronic properties of the as‐deposited and selenized CIS precursors were characterized by various techniques. A 10% CIGS based thin film solar cell was developed using the electrodeposited and thermally processed film. The cell structure consisted of . The cell parameters such as Jsc, Voc, FF, and η were determined from I–V characterization of the cell.

Synthesis, Electrooxidation, and Characterization of Bis(diphenylamine)naphthalene Diimide

We have synthesized a new poly(imide) precursor for solution electrodeposition onto conducting surfaces. The new monomer, N,N‘-bis[p-phenylamino(phenyl)]-1,4,5,8-naphthalenetetracarboxylic diimide (DNTD), contains a central naphthalene diimide moiety flanked by two dimerizable diphenylamine groups. DNTD was oxidatively electrodeposited onto Au-, Pt-, and In-doped SnO2 surfaces from DMSO, CH3CN, and CH2Cl2. The cyclic voltammetry is consistent with initial radical cation formation of diphenylamine groups, and then para C−C coupling of radicals to form dimers and higher order oligomers. IR spectroscopy was used to determine the average degree of polymerization and confirm para coupling. The resulting material shows electrochemically reversible 1e-/ and 2e-/monomer unit reduction waves corresponding to the naphthalene tetracarboxylic diimide radical anion and dianion. Also a quasireversible 1e-/ and 2e-/monomer unit oxidation corresponding to the oxidation of diphenylbenzidine unit is shown. Visible−NIR spec...