Conducting Glass Substrates Research Articles

Self‐Assembled Urchin‐Like CuWO4/WO3 Heterojunction Nanoarrays as Photoanodes for Photoelectrochemical Water Splitting

AbstractWith attractive visible‐light response and chemical stability, CuWO4 has emerged to be a promising candidate as a photoanode for photoelectrochemical (PEC) water oxidation. In this work, we report a one‐step hydrothermal method to prepare CuWO4‐based films directly grown on a conductive glass substrate from a stable precursor solution. By controlling the reaction duration, CuWO4/WO3 heterojunctions with urchin‐like nanoarray morphology are obtained. The CuWO4/WO3 film obtained with an optimized hydrothermal reaction time exhibits an onset potential of 0.6 V and a photocurrent density of 0.48 mA cm−2 at 1.23 V vs. RHE, which is almost five times that of bare CuWO4. The superior structure of the urchin‐like array with large surface area, optimizing film thickness for adequate light absorption and formation of heterojunctions for efficient charge separation conjointly, contributes to the improved performance as well as robust stability.

Opto-electronic properties of electrodeposited ZnTe using zinc anode as counter electrode

Successful electrodeposition of ZnTe thin films on fluorine doped tin oxide (FTO) conducting glass substrates have been achieved using a 2 - electrode configuration system with Zn anode as counter electrode. The thin films were prepared from an electrolyte containing ZnSO4.7H2O and dissolved TeO2 solution using different cathodic potentials. The prepared films were characterised for their electrical and optical properties by using photo-electro-chemical (PEC) cell measurement and UV–Vis optical spectrophotometer instruments respectively. Within the range of the deposition potentials explored in this work, the PEC cell results revealed that the electroplated materials have p-type electrical conductivity of different magnitudes. The optical results indicated that the energy band gap for electrodeposited (ED) ZnTe thin films using Zn as the anode electrode were in the range of (2.00–3.10) eV ± 0.02, depending on the deposition potential. The excellent optical properties observed in the ED-ZnTe layers using zinc anode electrode will make the films useful as optical materials for solar cells application.

The effect of CuS counter electrode microtopography on the properties of quantum dot sensitized solar cells

The counter electrode (CE) is an essential working part in quantum dots sensitized solar cells (QDSCs), which performs the function of extracting electrons form external circuit and catalyzing the reduction of electrolyte. Usually, CuS based composite acts as CEs in QDSCs to realize the dual functions. In this work, the microtopography of CuS film on FTO glass was modified through changing preparation route and conditions to investigate the possibility of mono component CuS film as CEs in liquid junction QDSCs. Two kinds of CuS CEs were prepared on FTO conductive glass substrate through successive ionic layer adsorption and reaction (SILAR) and modified hydrothermal method, respectively. Based on the results of XRD, SEM and EDX characterization, ECS and J-V curves were analyzed to investigate the effect of CEs’ particle size, microstructure and film morphology on the photovoltaic properties of QDSC samples. The results showed that CuS CEs prepared through appropriate SILAR cycle times exhibited higher catalyzing ability due to smaller diameter of CuS particles and uniform distribution of CuS particles in film, compared with those with modified hydrothermal method. CuS CEs with 10 deposition cycles showed the best catalyzing ability of the lowest charge transfer resistance (3.00 Ω) on CE/electrolyte interface and the power conversion efficiency (PCE) of QDSC consisting of this CuS CE reached 3.83%.

Functions of MnOx in NaCl Aqueous Solution for Artificial Photosynthesis.

SummaryPhotoelectrochemical water splitting has been intensively investigated as artificial photosynthesis technology to convert solar energy into chemical energy. The use of seawater and salted water has advantages for minimum environmental burden; however, the oxidation of Cl− ion to hypochlorous acid (HClO), which has toxicity and heavy corrosiveness, should occur at the anode, along with the oxygen evolution. Here, O2 and HClO production in aqueous solution containing Cl− on photoanodes modified with various metal oxides was investigated. The modification of MnOx resulted in the promotion of the O2 evolution reaction (OER) specifically without HClO production over a wide range of conditions. The results will contribute not only to the practical application of artificial photosynthesis using salted water but also to the elucidation of substantial function of manganese as the element for OER center in natural photosynthesis.

Homogeneous Co3O4 film electrode with enhanced oxygen evolution electrocatalysis via surface reduction

Homogeneous NaBH 4 -reduced Co 3 O 4 thin film electrodes with enhanced oxygen evolution electrocatalysis were obtained via a controlled-synthesis route. Firstly CoO x colloids were synthesized via ethylene glycol solvothermal method and cast on conductive glass substrates. The oxygen evolution reaction (OER) electrocatalysis of these as-prepared Co 3 O 4 thin films were then significantly enhanced via a simple surface reduction by NaBH 4 solution. The OER catalytic performance of the NaBH 4 -reduced thin films was strongly dependent on the NaBH 4 concentration. The use of NaBH 4 -reduced thin film electrodes for OER in alkaline solution supported higher current density and consequently negative shifts of the onset potential compared to that of the pristine. The optimal B 12.5, 20 -Co 3 O 4 thin films exhibited excellent OER catalytic performances: At the current density of 10 mA·cm −2 , a low overpotential of 365 mV and a small Tafel slope of 59.0 mV·dec −1 were observed. In addition, these B 12.5, 20 -Co 3 O 4 thin film electrodes possessed good stability that can well recover its OER performance in a 24-h chronoamperometric stability test. Homogeneous NaBH 4 -reduced Co 3 O 4 thin film electrodes with enhanced oxygen evolution electrocatalytic performance and stability was obtained via a controlled-synthesis route.

Enhancing the electron transfer process of TiO2-based DSSC using DC magnetron sputtered ZnO as an efficient alternative for blocking layer

Abstract Developing dye sensitized solar cell (DSSC) technology by exploiting different alternative semiconductors has attracted research attentions. Among all types of semiconductors, ZnO nanostructures due to their unique electrical properties and the facile preparation of various morphologies, have considered as the promising materials for application in DSSCs. In the present study, DC magnetron sputtering method was utilized to prepare a ZnO thin film as an efficient alternative for TiCl4 pre-treatment to suppress the charge recombination process occurring at a conventional TiO2-based DSSC. Different thicknesses of ZnO seed layers on fluorine tin oxide conductive glass substrates (FTO) were prepared via various sputtering deposition times. Field emission-scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD) analyses were utilized to study the surface uniformity and crystallinity of the ZnO nanostructures. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed to investigate the photoanode interface properties via determination of the electron lifetime and density of electron in conduction band. The results demonstrated that the thickness of ZnO compact layer which either acts as electron trapping states or blocking layer has the important role in cell performance. Finally, by the optimum thickness of ZnO thin film, the highest efficiency was achieved at 5.1%.

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.

Synthesis of Bi2S3 thin films based on pulse-plating bismuth nanocrystallines and its photoelectrochemical properties.

The solubility of Bi3+ in aqueous solution is an important factor that limits the fabrication of high-quality Bi2S3 thin films. In order to find a low-cost method to manufacture high-quality Bi2S3 thin films, we are reporting the preparation of the Bi2S3 thin films based on pulse-plating method in this paper for the first time. The nano-bismuth particles were obtained by electroplating on fluorine-doped SnO2 (FTO)-coated conducting glass substrates with saturated bismuth potassium citrate solution as the electroplating bath, and then it was put into a muffle furnace to oxidize. Finally, the thin films depositing on FTO glass substrates were put into the thioacetamide solution for vulcanization. In the end, the Bi2S3 thin films were successfully prepared on FTO glass substrates. Different characterization techniques were used to characterize the structure, morphology and photoelectrochemical properties of the prepared thin films. The test results revealed that we used this method to synthesize the high-quality Bi2S3 thin films, thus the Bi2S3 materials synthesized through this method are promising candidates in photoelectrochemical application.

Silver nanoparticles coupled ZnO nanorods array prepared using photo-reduction method for localized surface plasmonic effect study

Coupling of selected metal nanoparticles (NPs) on the surface of ZnO nanorods (NRs) array grown on conductive glass substrates is one of the approaches to tailor the optical properties of ZnO NRs. It is a metal oxide deposition process followed by an annealing treatment to convert the deposits to metal NPs. However, the conductive glass substrates could easily deform during this annealing process. This issue limits the application of ZnO NRs array that grown on glass substrates for the fabrication of ZnO based devices. Thus, the development of metal NPs deposition technique without the need of post-deposition annealing is highly desired. This work demonstrated a successful and controlled deposition of silver (Ag) NPs on ZnO NRs array grown on fluorine doped tin oxide (FTO) glass substrates without any post-deposition annealing and, the product has exhibited localized surface plasmonic resonance (LSPR) phenomenon. The ZnO NRs arrays were grown on FTO glass substrates that pre-seeded with ZnO layer using hydrothermal method. The controlled coupling of Ag NPs particles on ZnO NRs was performed by adjusting the duration of photo-reduction process. The optical bandgap ZnO NRs was widened because of Ag NPs coupling, i.e. from 3.16 to 3.22 eV; as estimated from the result of UV–Vis measurement. The shift of near band-edge emission (NBE) in room temperature photoluminescence (RTPL) suggests that the presence of Ag NPs on the surface of ZnO NRs could block the transitions of electrons in ZnO whereas the shift in defect-related emission indicates the generation of defects at the interfaces between Ag NPs and ZnO NRs. The 5-folds increment of IUV/Vis ratio of Ag NPs/ZnO NRs in RTPL, indicating the specimens experienced LSPR effect. The LSPR effect of Ag NPs/ZnO NRs could be used to improve the performance of ZnO-based devices such as solar cells, light-emitting diodes and photocatalysts applications.

Electron transport enhancement in perovskite solar cell via the polarized BaTiO3 thin film

Abstract

Based on the Study on Preparation and Properties of Co(II) and La3+-Doped TiO2 Electrochromic Film

In order to improve the optical properties and coloration effect. Co(II) and La3+ doped TiO2 thin films were synthesized via a sol–gel, by using butyl titanate as precursor on the surface of ITO conductive glass substrate. Several techniques were used to characterize produces. Adopting the Sol-gel technology, [CH3(CH2)3O]4Ti, La2O3, CoCl2•6H2O as the precursor, the composite membranes with different molar ratio of Ti, Ti/La, Ti/Co to be prepared on the ITO glass substrate, the optimum technological parameters for preparation of the base material of the electro-induced discoloration glass are determined. The structure and surface morphology optical and electrochromic properties of Co(II) and La3+-doped TiO2 films were examined with X-ray diffraction (XRD) analysis, energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), and ultraviolet-visible spectrophotometer (UV-vis) DTA-TG analysis. It was found that:The sintering temperature coating number, [CH3(CH2)3O]4Ti content of the TiO2 film sample, and the doping category are the main factors that affect the structure and properties of the membrane based material;Using two alcohol amine as chelating agent can effectively inhibit the formation of Ti (OH)4 precipitation;The properties of the TiO2 glass film prepared by La2O3 and CoCl2·6H2O are fine;Materials based on the preparation of a radiochromic film transmittance, high cyclic reversibility, cyclic voltammetry characteristics significantly, the results of the study for the electric induced radiochromic film-based material development and application provide a theoretical and experimental basis.

Tuning Coordination Geometry of Nickel Ketoiminates and Its Influence on Thermal Characteristics for Chemical Vapor Deposition of Nanostructured NiO Electrocatalysts.

Nickel-based nanostructured materials have gained widespread attention, particularly for energy-related applications. Employing chemical vapor deposition (CVD) for NiO necessitates suitable nickel precursors that are volatile and stable. Herein, we report the synthesis and characterization of a series of new nickel β-ketoiminato complexes with different aliphatic and etheric side chain substitutions, namely, bis(4-(isopropylamino)-pent-3-en-2-onato)nickel(II) ([Ni(ipki)2], 1), bis(4-(2-methoxyethylamino)pent-3-en-2-onato)nickel(II) ([Ni(meki)2], 2), bis(4-(2-ethoxyethylamino)pent-3-en-2-onato)nickel(II) ([Ni(eeki)2], 3), bis(4-(3-methoxy-propylamino)-pent-3-en-2-onato)nickel(II) ([Ni(mpki)2], 4), and bis(4-(3-ethoxypropylamino)pent-3-en-2-onato)nickel(II) ([Ni(epki)2], 5). These compounds have been thoroughly characterized with regard to their purity and identity by means of nuclear magnetic resonance spectroscopy (NMR) and electron impact mass spectrometry (EI-MS). Contrary to other transition metal β-ketoiminates, the imino side chain strongly influences the structural geometry of the complexes, which was ascertained via single-crystal X-ray diffraction (XRD). As a result, the magnetic momenta of the molecules also differ significantly as evidenced by the magnetic susceptibility measurements employing Evan's NMR method in solution. Thermal analysis revealed the suitability of these compounds as new class of precursors for CVD of Ni containing materials. As a representative precursor, compound 2 was evaluated for the CVD of NiO thin films on Si(100) and conductive glass substrates. The as-deposited nanostructured layers were stoichiometric and phase pure NiO as confirmed by XRD, Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). X-ray photoelectron spectroscopy (XPS) indicated the formation of slightly oxygen-rich surfaces. The assessment of NiO films in electrocatalysis revealed promising activity for the oxygen evolution reactions (OER). The current densities of 10 mA cm-2 achieved at overpotentials ranging between 0.48 and 0.52 V highlight the suitability of the new Ni complexes in CVD processes for the fabrication of thin film electrocatalysts.

Pulse laser annealing activates titanium-doped hematite photoanodes for photoelectrochemical water oxidation

Efficient activation of donor-type dopants is important for promoting the photoelectrochemical (PEC) performance of semiconductor photoanodes. High temperature annealing, the most often-adopted method, can active the dopants, but is accompanied by serious deterioration of the conductive substrate. Hence, it still remains a challenge to develop a new method to activate the dopants in semiconductor photoanodes deposited on a substrate that is not resistant to high temperature. Herein, we report a pulse laser annealing (PLA) strategy to activate titanium dopant in hematite photoanodes at room temperature to improve the PEC performance for water splitting. A short treatment with 450 nm nanosecond yttrium aluminum garnet (YAG) laser (20 pulses, 30 mJ cm−2 per pulse) causes crystallinity improvement and surface roughening of hematite photoanodes without destroying the fluorine doped SnO2 (FTO) conductive glass substrate, and results in a 1.85-fold increased photocurrent density (0.484 mA cm−2, 1.23 V vs. RHE) of Ti-doped hematite photoanodes (5% doping level, Ti:Fe2O3-PLA). The charge transfer efficiency at the surface of Ti:Fe2O3-PLA was approximately two-fold higher than Ti:Fe2O3, and a 10.1-fold increased donor density (1.29 × 1019 cm−3) was achieved, demonstrating the potential of PLA treatment for activating doped semiconductor photoanodes at room temperature.

Effects of Solution Precursor on Structural, Morphological, and Photoelectrochemical Properties of ZnO Layers Deposited by Recurrent Cyclic Voltammetry

The effects of the choice of the starting solution on the crystalline growth and structural and photoelectrochemical properties of zinc oxide films deposited on conductive (fluorine-doped tin oxide) glass substrate by cyclic voltammetry at 70°C have been studied. The morphology of the deposits was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photoelectrochemical response in K2SO4 solution was followed by voltammetry and chronoamperometry. X-ray diffraction analysis revealed hexagonal wurtzite crystalline structure for all the films, with randomly oriented crystallites for the ZnO film prepared from zinc chloride or from an equimolar mixture of zinc chloride and zinc nitrate. Meanwhile, the films developed from zinc nitrate or from zinc acetate solution presented preferential (002) orientation. SEM revealed nanometric grains with hexagonal shape for all the films. The effects of the choice of the precursor on the symmetry, kurtosis, and roughness of the different films was evidenced by AFM, revealing that the roughness varied from 40 nm to 87 nm depending on the starting solution. The photoelectrochemical performance of the films was evaluated by chronoamperometry, revealing a strong anodic photocurrent and confirming their n-type semiconducting nature.

Activity of sol-gel derived nanocrystalline WO3 films in photoelectrochemical generation of reactive chlorine species

Conventional chlor-alkali method used for production of chlorine gas and chlorine-based disinfectants is among the most energy-intensive processes in chemical industry, therefore, more sustainable alternatives with lower carbon footprint are sought. Photoelectrochemical (PEC) generation of reactive chlorine species (Cl2, HClO, ClO−) is a promising technology in the area of water disinfection and purification, as it combines the advantages of (i) using the renewable solar energy; (ii) possibility to produce disinfectants on-site and on-demand and (iii) eliminates the need for sophisticated infrastructure for storage and handling of chlorine species.In the present study nanocrystalline tungsten (VI) oxide layers were formed on conducting glass substrate using simple sol-gel synthesis technique and polytethylene glycol as a structure-directing agent. It is shown that addition of PEG in moderate amounts favours formation of the structure of interconnected nanocrystalline particles, which ensures effective separation and transport of photogenerated charge carriers and, therefore, is crucial for the photoelectrochemical activity of the films. This is corroborated by the analysis of SEM and XRD data, revealing the influence of polytethylene glycol from the initial stages of WO3 phase crystallization. Faradaic efficiency of photoelectrochemical hypochlorite formation is shown to be about 30%, and antimicrobial effect of PEC chlorination with WO3 photoanodes is demonstrated on Gram-positive Bacillus sp. and Gram-negative E.coli C41(DE3) bacteria.

Light-enhanced Electrochemical Energy Storage of Synthetic Melanin on Conductive Glass Substrates

ABSTRACTEumelanin is a redox active, quinone-based biopigment, featuring a broad band absorption in the UV-Vis region. The combination of the redox and optical properties makes eumelanin an interesting candidate to explore light-assisted storage technologies. Electrodes of melanin on indium tin oxide (ITO) current collectors were investigated for their morphological and voltammetric characteristics in aqueous electrolytes. Under solar light, we observed that the capacity and the capacitance of the melanin electrodes significantly increase with respect to the dark conditions (by 63% and 73%, respectively).

Electrodeposition of Cu2o/MoS2 Thin Films on Fto Substrate As a Heterojunction Photoelectrochemical Cell for Water Splitting

The layered structure MoS2, an n-type conductor (bandgap of 1.9-2 eV), can be excited under irradiation with visible light. However, its valence band energy (-4.2 eV) is closed to the minimum energy required to reduce water into hydrogen (- 4.2 eV at pH = 7). The p-type semiconductor Cu2O (a bandgap of 2 eV) has a valence band energy of - 4.0 eV, higher than that of MoS2 and therefore has potentially as photocatalytic for water splitting. In this work, the heterojunction of Cu2O/MoS2 is prepared on a conductive FTO-coated glass substrate by electrodeposition methods. We conduct initially the MoS2 thin film on FTO by cyclic voltammetry (CV). Then, the Cu2O thin film is deposited on the MoS2/FTO thin film by double-potential pulse chronoamperometric (DPPC) to form a p-n junction Cu2O/MoS2/FTO photo-electrode which play an anodic role in a photoelectrochemical cell. The structure, morphology and composition of heterojunction electrode are characterized by powder X-ray diffraction, SEM, TEM, IR, Raman spectroscopy, electrochemical impedance spectroscopy (EIS). The optical properties are determined by UV-VIS spectroscopy and Photoluminescence (PL) spectroscopy. The photoelectrochemically catalytic activity of the electrodes is performed in dark condition and light condition with 1.5 AM from a solar simulator system by Linear-sweep voltammograms and Transient photocurrent-time methods. The H2-generation yield is evaluated by gas chromatography. The effect of the structure and the composition of the Cu2O/MoS2 thin films on the kinetics and mechanism of the photoelectrochemical water splitting is also considered.

Nanostructured CuO film grown from solution by preferential microwave heating of the conducting glass substrate

Nanostructured Cu(II) oxide receives significant attention because of its possible applications. Very well adhered CuO films have been grown on conducting glass substrates using microwave-activated chemical bath deposition, at low temperature and in a short time. X-ray diffraction and Raman spectroscopy show that only the CuO tenorite phase is present. Scanning electron microscopy reveals a peculiar nanostructured morphology: nanowires or nanobranches that have fallen on the substrate after growing into the precursor solution, perpendicular to it. A gap value, Eg = 1.52 eV, is obtained from the diffused reflectance spectrum. Film characteristics are of interest for some applications, particularly, solar radiation harvesting.

Light conducting photocatalytic membrane for chemical-free fouling control in water treatment

This work shows for the first time the convenient in-situ UV illumination of a titanium dioxide (TiO2) photocatalytic membrane via a sintered porous glass substrate for effective fouling reduction during water treatment. By directing light through the light conducting glass substrate, this concept overcomes the current challenge of photocatalytic membranes that direct light through turbid, light obstructing feed waters. Fouling was tested by filtering model solutions of humic acid (HA), bovine serum albumin (BSA) or sodium alginate (SA). Photocatalysis initiated by simply directing light via the permeate side through the porous glass substrate led to significant reductions in trans-membrane pressure (TMP) rise rates between backwashes and all model organic fouling compounds. Specifically, the UV-light exposed membranes showed a 3.0-fold and 2.4-fold reduction in total filtration resistance for BSA and SA solutions, respectively, which also showed 2.7-fold and 4.2-fold reductions in the irreversible fouling indices. Analysis by SEM coupled with fouling modelling showed the beneficial anti-fouling effects stemmed from reduced intrusion of organic material inside the TiO2 membrane pores, as well as reduced cake layer resistance. The novel, convenient light conducting photocatalytic membranes concept could be used for sustainable, low-chemical membrane filtration of polluted water.

Synthesis and characterization of CdTe thin film on FTO by electrodeposition technique for CdTe/CdS solar cells

In this work, the synthesis of the CdTe thin film (absorber layer) on fluorine-doped Tin oxide (FTO) substrate by electrodeposition technique of CdTe/CdS solar cell has been presented. As a result of the superior efficiency in energy conversion by absorbing energy in a broad range of the solar spectrum, thin film CdS/CdTe solar cells have been paid attention worldwide as a potential candidate for photovoltaics (PV). The electrodeposition (ED) technique is suitable for the synthesis of CdTe material due to its ease, low cost, scalability and manufacturability. Usually, the quality of these deposited thin films depends on several growth parameters, and the type of conducting glass substrate plays a crucial role. CdTe material grown up on the top of the FTO coated glass substrate having dimensions 75mm* 25mm*1mm and was characterized for its optical properties by UV-Vis spectrometer (UV-Vis), Photoluminescence (PL) and Fourier transform infrared spectrometer (FTIR). XRD result confirms the cubic crystalline character of the deposited material. The band gap of CdTe film estimated using Tauc’s plot is found to be 1.5eV. It is expected that this article will enrich the features of CdTe/CdS devices for solar energy conversion and stimulate further innovative research interest on this interesting topic.