Photoelectrochemical Cell Application Research Articles

Synthesis and characterization of temperature-dependent nanospherical Cu2−xSe thin films for photoelectrochemical cell application

Synthesis and characterization of temperature-dependent nanospherical Cu2−xSe thin films for photoelectrochemical cell application

Fabrication of Ag injection in Bi2S3 (AgBiS2) thin films for photoelectrochemical cell applications

Fabrication of Ag injection in Bi2S3 (AgBiS2) thin films for photoelectrochemical cell applications

Fabrication of single-step novel synthesis of ZnCd(S0.5Se0.5)2 thin films for photoelectrochemical (PEC) cell application

In our study, we use a new method called the arrested precipitation technique (APT) to create CdZn(SSe)2 (CZSS) thin films. We obtain samples at different deposition times, ranging from 2.5 to 4 h, and analyze the effects of deposition time on the opto-structural, morphological, compositional, and photoelectrochemical (PEC) solar cell properties. As a result, we find that the band gap energy increases from 2.366 to 2.60 eV with prolonged growth time, as shown by UV–Vis spectra. X-ray diffraction (XRD) analysis confirms that the crystal structure is hexagonal, with the crystallite size increasing from 76 to 93 nm. The dislocation density and microstrain, determined by the Scherrer formula, decrease from 1.72 to 1.14 lines m−2 and from 4.75 × 10−3 to 3.87 × 10−3 (lines m−2), respectively. These results are validated using the Williamson-Hall (WH) plot and size-strain plot. The average grain size, evaluated using the standard scale bar method in scanning electron microscopy (SEM), ranges from 80 to 150 nm across CZ1 to CZ4 samples. Transmission electron microscopy (TEM) images of CZ4 and CZ2 reveal particle sizes of 101 nm and 87 nm, respectively, while selected area electron diffraction (SAED) patterns confirm the polycrystalline nature of the material. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirm the presence of Cd, Zn, S, and Se elements in their intended stoichiometry. Notably, CZSS photoelectrodes deposited over 4 h show better performance in Photoelectrochemical cells (PEC), achieving the highest photoconversion efficiency (ɳ) at 2.33 %, as evidenced by J-V measurements.

Photoelectrochemical Cells with a Pyridine-Anchored Bilayer Photoanode for Water Splitting.

A dye-sensitized photoanode is prepared by coassembling a Ru complex photosensitizer and a Ru water oxidation catalyst (WOC) on a TiO2 substrate, in which the WOC molecules are immobilized in a layer-by-layer fashion through metal-pyridine coordination with the aid of a bifunctional anchoring and bridging molecule containing multiple pyridine groups. Under visible-light irradiation, an anodic photocurrent of around 200 μA/cm2 has been achieved with O2 and H2 being generated at the photoanode and Pt counter electrode, respectively. The pyridine anchoring strategy provides a simple method to prepare photoelectrodes for applications in photoelectrochemical cells.

On the Scope of the Oxygen Plasma Treatment on FTO Electrodes for Electrochemical Processes

The cleaning and/or activation of electrodes for electrochemical purposes using the oxygen plasma treatment has been widely used because of its proven effectiveness to improve the properties of electrodes. Beyond its cleaning effect, the plasma can either create stepped and functionalized carbon-based materials which are active for specific electroanalytes and increase their capacitance [1]. Prussian Blue can also be activated by creating oxygen rich sites thus enhancing its electrochromism [2]. In the case of transparent conductive oxides (TCOs) electrodes such as FTO and ITO-coated glass this treatment has proven to be suitable in the preparation of spray-pyrolyzed titania thin films used as blocking hole layer or electron transporting layer in efficient third generation solar cells [3]. However, the role of this treatment on TCOs when used for electrochemical purposes has not been deeply explored yet. The reason to carry out this study lies in the great number of electrochemical processes that are usually employed for the growth of wide and middle band gap semiconductor metal oxides and chalcogenides with applications in photoelectrochemical and photovoltaic cells [4].To assess the role of the oxygen plasma, FTO was chosen as TCO reference material and the effect of different time exposure and power of plasma was analysed by electrochemical polarization in aqueous media for both anodic and cathodic directions. In the former, PbO2 electrodeposition and oxygen evolution reaction (OER) were considered. In the later, hydroxide generating reactions that usually precipitate in presence of transition metal cations were studied: i) the oxygen reduction reaction (ORR, Figure 1), ii) hydrogen peroxide reduction. Further, the reduction of S8 in DMSO media to sulphide ion was also considered as an aprotic media to growth chalcogenides. Interestingly, all these electrochemical reactions exhibited an increased activation overpotential. The behaviour of treated FTO for OER demonstrated the as implanted oxyanions do not act as source of molecular oxygen as previously claimed [5]. This was verified by the poorly response of ORR after anodic polarizations in acid media.Besides, contact angle measurements allowed to estimate the energetic of the FTO surfaces being these energies correlated with open circuit potential values. Capacitance (Mott-Schottky plots), XPS, UPS and UV-Vis spectroscopy were used to study the semiconductor energy levels of both treated and untreated FTO electrodes. The oxyanion implantation in the oxygen vacancies would be responsible of the sharply diminution of the ORR wave. However, the electrochemical response of the well-known Ferri/Ferro couple only suffered changes under highly aggressive treatments, i.e. for long times or power. Meanwhile, XRD data has shown only slight changes in the structural features of FTO. We can conclude that oxygen plasma treatment is not suitable in FTO for electrochemical purposes, contrary to other deposition methods. Surprisingly, an exception in metals deposition (Ni and Zn) was found.

Structural Engineering Three-Dimensional Nano-Heterojunction Networks for High-Performance Photochemical Sensing.

Nanoscale heterojunction networks are increasingly regarded as promising functional materials for a variety of optoelectronic and photocatalytic devices. Despite their superior charge-carrier separation efficiency, a major challenge remains in the optimization of their surface properties, with surface defects playing a major role in charge trapping and recombination. Here, we report the effective engineering of the photocatalytic properties of nanoscale heterojunction networks via deep ultraviolet photoactivation throughout their cross-section. For the first time, in-depth XPS analysis of very thick (∼10 μm) NixOy-ZnO films reveals localized p-n nanoheterojunctions with tunable oxygen vacancies (Vo) originating from both NixOy and ZnO nanocrystals. Optimizing the amount of oxygen vacancies leads to a 30-fold increase in the photochemoresistive response of these networks, enabling the detection of representative analyte concentrations down to 2 and 20 ppb at an optimal temperature of 150 °C and room temperature, respectively. Density functional theory calculations reveal that this performance enhancement is presumably due to an 80% increase in the analyte adsorption energy. This flexible nanofabrication approach in conjunction with straightforward vacancy control via photoactivation provides an effective strategy for engineering the photocatalytic activity of porous metal oxide semiconductor networks with applications in chemical sensors, photodetectors, and photoelectrochemical cells.

Ni(II)-doped CuWO4 photoanodes with enhanced photoelectrocatalytic activity

CuWO4 has emerged in the last years as a ternary metal oxide material for photoanodes application in photoelectrochemical cells, thanks to its relatively narrow band gap, high stability and selectivity toward the oxygen evolution reaction, though largely limited by its poor charge separation efficiency. Aiming at overcoming this limitation, we investigate here the effects that Cu(II) ion substitution has on the photoelectrocatalytic (PEC) performance of copper tungstate. Optically transparent CuWO4 thin-film photoanodes, prepared via spin coating and containing different amounts of Ni(II) ions, were fully characterized via UV–Vis spectroscopy, XRD and SEM analyses, and their PEC performance was tested via linear sweep voltammetry, incident photon to current efficiency and internal quantum efficiency analyses. From tests performed in the presence of a hole scavenger-containing electrolyte, the charge injection and separation efficiencies of the electrodes were also calculated. Pure-phase crystalline and/or heterojunction materials were obtained with higher PEC performance compared to pure CuWO4, mainly due to a significantly enhanced charge separation efficiency in the bulk of the material.Graphic abstract

Investigation of optical and electronic characteristics of Bʹ site arranged Cs2NaB′Cl5 (B′= Ni, Mn, Fe) double perovskite: A theoretical and experimental study

This study delves into the exploration of B′ site arranged Cs2NaB′Cl5 perovskites (B′ = Ni, Mn, Fe) as prospective alternatives to lead-based perovskites, given the environmental concerns associated with lead toxicity and material instability. Structural analysis using X-ray diffraction revealed a stable tetragonal crystal structure with the P4/mmm space group. Electronic properties, assessed via density functional theory (DFT) calculations, identified these materials as p-type semiconductors with tunable band gaps, and this finding supported by optical experimental data. Thermogravimetric analysis (TGA) demonstrated decomposition temperatures up to 750 °C, with Cs2NaMnCl5 exhibiting superior thermal stability. Field emission scanning electron microscopy (FESEM) unveiled distinct morphologies influenced by the transition metal in the B′ site, while elemental analysis confirmed material purity. The optical analysis revealed strong light absorption in the visible spectrum, highlighting the potential of these materials for sustainable energy conversion applications. Overall, this research contributes valuable insights into the environmental-friendly potential of B′ site arranged Cs2NaB′Cl5 perovskites in photoelectrochemical and solar cell application.

Microwave-induced band gap attenuation of novel manganese zinc aluminum sulfide kesterite nanomaterials for optimal photovoltaics

Recently, kesterite (copper zinc tin sulfide, CZTS) have emerged as a promising alternative active layer to cadmium telluride and copper indium gallium selenide for low-cost thin films for solar cell applications due to its high absorption coefficient, direct band gap, natural abundance, and low toxicity. The photovoltaic power conversion efficiency achieved with CZTS is still very low when compared to silicon, thereby hindering its commercialization. Developing new materials with improved optical and photovoltaic properties is, therefore, encouraged. Here, we report for the first time the microwave-assisted solvothermal synthesis of novel manganese zinc aluminum sulfide using chlorides, sulfates, nitrates and a mixture of chlorides, nitrates, and sulfates in ratio 1:1:1 as cation precursor salts. The influence of microwave reaction temperatures from 100 to 190 °C for 5–60 min were investigated on the crystal structure, morphology, composition, optical, and electrochemical properties. It has been found out that the microwave reaction temperature and time have potential effect on the overall reaction. The optimum temperature and time were found to be 190 °C for 5 min and 150 °C for 20 min for our studies. The obtained powder samples were analyzed using X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared, ultraviolet-visible, cyclic voltammetry, and electrochemical impedance spectroscopy. Structural characterization using X-ray diffraction revealed that the samples synthesized with chlorides, nitrates, and mixtures of the precursor salts were all amorphous while samples synthesized with sulfate precursor salts have a kesterite crystal structure. Raman spectroscopy shows major intense peaks between 326 and 331 cm for all the nanomaterials which could be assigned to the Raman A mode of kesterite CZTS. The morphological features revealed spherical shapes with little agglomeration for all the synthesized materials except for that synthesized with sulfate precursor salts at 190 °C revealing a rod-like morphology with a width of 0.780–1.200 μm, a length of 1.90–2.5 μm and attached to the surface are agglomerated nanospheres. Small-angle X-ray spectroscopy revealed a core-shell shape for most of the nanomaterials with an average particle size between 10 and 100 nm. Electrochemical impedance spectroscopy revealed that electron transfer is faster in the nanomaterials synthesized with the chloride precursor salts at both temperatures studied. The band gap falls within the range of 1.2–1.7 eV. The nanomaterials presented in this study possess the desirable properties for application in photoelectrochemical and solar cells.

Hydrogen generation ability of B-site substituted two-dimensional Can-1Tin-3Nb3O3n+1− perovskite nanosheets in photoelectrochemical cell

Many semiconductor materials have been researched for hydrogen evolution application, in which 2D nanosheet materials are given a bunch of investigation due to their suitable energy band edges and proper band gap. The studying of a novel B-site substituted 2D perovskite nanosheets, Can-1Tin-3Nb3O3n+1− (CTNO−), with a layer number n = 4, 5, and 6 shows that these n-type semiconductors have unique properties with large band gaps (3.71 – 3.78 eV). These Dion-Jacobson family members, titaniobate nanosheets, are fabricated by substituting partially transition metal Ti elements into the Nb element positions (B sites) of the niobate (NbO6) perovskite structure. A well crystalline structure and the ability in hydrogen generation are exhibited. The energy band diagrams of CTNO− (n = 4, 5, and 6) nanosheets are determined and established. The photoelectrochemical devices made of B-site substituted CTNO−nanosheets are carried out for investigating of the ability in hydrogen generation reaction. The CTNO− (n = 5) nanosheets performs the water splitting capability with the highest hydrogen generation efficiency. The hydrogen generation efficiency is improved by a p-n composite combining CTNO− (n = 4, 5, and 6) nanosheets with a conductive polymer of PEDOT:PSS. The highest efficiency of hydrogen generation is belonging to CTNO− (n = 4)/PEDOT:PSS with a hydrogen formation rate of 5.576 × 102 µmol h−1 g−1. Concerning all these performances, these Dion Jacobson phase CTNO− (n = 4, 5, and 6) nanosheets are considered for ultrathin scale photoelectrochemical cell or phototransistor applications.

Enhanced charge carrier density of a p-n BiOCl/BiVO4 heterostructure by Ni doping for photoelectrochemical applications

Pure and doped p-n BiOCl/BiVO4 heterostructures with various Ni contents were studied for photoanode applications in photoelectrochemical cells. All materials were synthesized by the coprecipitation method. The properties of the pure and doped materials were characterized by various techniques, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UVvisible spectroscopy, and electrochemical impedance spectroscopy. Furthermore, density function theory calculations were employed to investigate the underlying physical mechanism of the Ni substitution. The materials were applied as the photoanode at an applied bias voltage of +1.9 V (vs. RHE) and irradiated over 4200 s under the solar light simulator. The pure p-n BiOCl/BiVO4 heterostructure showed the highest photocurrent of 1 mA/cm2. After 1% Ni doping, the photocurrent density was enhanced, and the highest photocurrent density was approximately 1.7 mA/cm2. From the theoretical calculation aspect, the role of Ni substitution into the parent p-n BiVO4 and BiOCl materials resulted in a surface state under the conduction band of both parent materials. The result was in agreement with the Mott-Schottky analysis, which showed that the charge carrier density increased as Ni atoms were added to the p-n BiOCl/BiVO4 heterostructure. Therefore, the additional state and the increase in the charge carrier density led to the improved photocatalytic activity of the Ni-doped p-n BiOCl/BiVO4 heterostructure.

Synthesis of Titanium Oxide Nanotubes for Photo Electrochemical Cells and its Characterizations

Nano scale materials have many peculiar properties than the bulk ones and have led to break through in various fields of science and technology. Titanium oxide is one of the excellent and most demanded materials because of its various applications and properties such as such as large surface area. In this paper, Titanium oxide (TiO2) nanotube arrays were synthesized by electrochemical anodization of titanium foil. Dimension of nanotubes and elemental composition were detected by Field Emission-Scanning Electron Microscope with Energy Dispersive X-Ray Analysis (FESEM- EDAX). From X- Ray Diffraction (XRD) the intensity of peaks, d- spacing values and phase of TiO2 nanotubes were analyzed. The Energy Bandgap (Eg) of the formed TiO2 nanotubes was determined by Diffuse Reflectance Spectroscopy from Kubelka-Monk Plot. From the obtained results, the synthesized TiO2 nanotubes are suitable for Photo Electrochemical Cell applications.

Photoelectrochemical Oxygen Evolution on Mesoporous Hematite Films Prepared from Maghemite Nanoparticles

Iron oxides, especially hematite (α-Fe2O3), are promising materials for applications in photoelectrochemical cells and photo-redox catalysis. However, realizing high-performance hematite photoanodes via an environmentally-friendly route remains a great challenge. In this work, we employed a novel approach to prepare mesoscopic hematite photoelectrodes with remarkable performance for water oxidation. Hydrothermally-synthesized maghemite nanoparticles of high crystallinity with a mean particle size of 3.3 nm were deposited onto fluorine doped tin oxide (FTO) transparent conducting glass substrates, followed by heat treatment to convert them into a homogeneous mesoporous hematite layer. A hematite photoanode with a thickness of 220 nm, delivered a maximum photocurrent density of 1.8 mA cm−2 for water oxidation to oxygen at 1.23 VRHE under simulated AM 1.5 irradiation. Upon treating the surface of the hematite photoelectrode with Co(II) cations the photocurrent density nearly doubled at the same potential to 3.32 mA cm−2 placing our new photoelectrode among the best hematite-based photocatalysts for visible light induced water splitting. Further photoelectrochemical analysis provided insights into the factors boosting the performance of the hematite photoanode.

Preparation and characterization of amine-terminated delafossite type oxide, CuMnO2–NH2, supported Pd (0) nanoparticles for the H2 generation from the methanolysis of ammonia-borane

Among the cuprous metal oxides of the delafossite type, which are generally formulated as CuMO2 (M = Al, Cr, Fe, Ga, Mn), the most promising is the CuMnO2 structures. CuMnO2 material, named crednerite, is a very interesting delafossite derivative with potential applications in many fields, mainly catalyst, photoelectrochemical cells and multiferroic tools. Herein, we report fabrication, characterization, and application of amine-terminated CuMnO2 (CuMnO2–NH2) supported palladium nanoparticles (Pd/CuMnO2–NH2) as highly efficient and recyclable catalysts for the hydrogen production from the methanolysis of ammonia-borane (AB). The results of characterization using P-XRD, TEM, HRTEM, TEM-EDX, XPS, SEM, SEM-elemental mapping, and ICP-OES disclose that Pd (0) nanoparticles were well spread on the surface of CuMnO2–NH2 with a mean particle size of 3.91 ± 0.33 nm. Pd/CuMnO2–NH2 shows high catalytic activity in the methanolysis of AB with an initial turnover frequency of 146.68 min−1 at 25 ± 0.1 °C which is one of the highest values ever reported for AB methanolysis in the literature. Besides, the extreme stability of Pd/CuMnO2–NH2 takes it a recyclable heterogeneous catalyst in this catalytic conversion.

Chemical reactions of graphitic carbon nitride films with glass surfaces and their impact on photocatalytic activity.

Thin films of graphitic carbon nitride (g-CN), a visible-light-driven photocatalyst, have recently attracted interest for application in photoelectrochemical cells for water splitting and high-throughput photocatalysis. In typical syntheses, g-CN films are formed by heating the nitrogen-rich precursor and substrate to 500-600 °C. The heated substrate should affect the polycondensation of the precursor and thereby alter the properties of the g-CN film. In this paper, we demonstrate that soda-lime glass, such as commercial glass slides, modifies the chemical structure of g-CN. The terminal amino groups of g-CN are partially substituted with cyanamide and hydroxyl groups. The electron-withdrawing groups provide the energy offsets of the frontier orbitals between the modified and unmodified molecules, facilitating exciton dissociation. After alkali metals are removed, the modified g-CN film exhibits a faster photodegradation of methyl orange compared with a melon film. The simple protocol to activate a g-CN film without co-catalysts paves a new way to enhance photocatalytic activity via selections of substrates, including waste glass.

Photoelectrochemical and photovoltaic cell performances of thermally evaporated Cu3BiS3 thin films

Photoelectrochemical cell and solar cell applications of Cu3xBi2-xS3 thin film with various ‘x’ values (x = 0, 0.25, 0.50, 0.75 and 1) are studied in the present investigation. Phase pure orthorhombic structured Cu3xBi2-xS3 (x = 1) is confirmed from the structural analysis. All the films have higher optical absorption in the visible region and the bandgap values are ranging from 2.26 eV to 1.81 eV for Cu3xBi2-xS3 (x = 0 to 1) films. Morphological analysis showed the uniform distribution of spherical shaped particles of Cu3xBi2-xS3 over the substrate. AFM analysis indicates decrease in surface roughness with increase of ‘x’ values. Electrical studies carried out using Hall effect analysis confirms ‘p’ type conductivity of Cu3BiS3. The photoconversion efficiency through the photoelectrochemical cell performance (PEC) of FTO/Cu3xBi2-xS3 (x = 0.25 to 1) films and solar cell behavior of FTO/Cu3xBi2-xS3 (x = 0.25 to 1)/CdS/Ag devices are reported.

Boosting photocurrent density of 1D TiO2 based photoanodes by bismuth vanadium oxide enhancement for photoelectrochemical cell application

A photoelectrochemical cell (PEC) is a device that can convert light energy into hydrogen fuel. In the present work, a 1D TiO2 based photoanode was enhanced by BiVO4 (BVO). All TiO2 and BVO/TiO2 photoanodes were fabricated by a hydrothermal method. Structural and surface morphology of the thin films were characterized by various spectroscopies. The 1D TiO2 and BVO/TiO2 nanorods were well aligned perpendicular to the fluorine doped tin oxide (FTO) substrate. X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) revealed BVO formation on the TiO2 surface, which was in agreement with the energy dispersive X-ray spectroscopy (EDS) and high resolution transmission electron microscopy (HRTEM) results. The bandgap of the TiO2 photoanode was decreased due to the BVO enhancement. According to UV–visible spectroscopy and the valence band binding energy from XPS, the estimated bandgap of BVO/TiO2 was 2.8 eV, while pure TiO2 was 3.1 eV. Based on this result, the PEC comprised of a BVO/TiO2 photoanode can harvest visible light. Electrochemical impedance spectroscopy (EIS) was performed to reveal the underlying physical properties when the PEC was operated. Upon illumination with a solar simulator, most of the PECs comprised of a BVO/TiO2 photoanode exhibited greater performance than the PECs comprised of a pristine TiO2 photoanode. The significant increase in performance was due to the light absorption extension to the visible region and the BVO anchoring, which leads to a low internal charge carrier resistance of the TiO2 based photoanode.

Two-Step Electrochemical Route to Synthesize Nanostructured Cu2O Thin Films

The conversion of solar energy to chemical fuels via a photoelectrochemical (PEC) cell is one promising approach to produce clean energy. A PEC cell consists of two light absorbing electrodes with appropriate optoelectronic properties. Depending upon the band alignment, one of two electrodes is a photoanode producing O2, and the other one is a photocathode which produces H2. One such suitable photocathode for a PEC cell is Cu2O; an intrinsic p-type semiconductor with a direct bandgap of 2.0 eV and a high absorption coefficient of 104 cm-1 in the visible range. Its conduction band minimum (CBM) lies 0.7 V negative of water reduction potential and therefore, can act as a photocathode. However, one major challenge associated with Cu2O is its poor minority carrier diffusion length resulting in a large recombination rate in bulk and lower overall cell efficiency. In this aspect, nanostructured materials are of great use owing to their inherent properties. Orthogonal charge separation, enhanced light absorption, and large electrode-electrolyte are few advantages of the nanostructured materials which can be used to overcome the issue of minority carrier diffusion length. However, the synthesis of nanostructured Cu2O thin films is quite challenging as it involves multiple steps and/or require high-temperature processing.In this work, we present a low temperature, and straightforward two-step synthesis method to obtain nanostructured Cu2O with 10-30 nm thick nano-walls on FTO coated glass substrate. First, the Cu2O thin films are electrodeposited at a potential of -0.35 V vs. Ag/AgCl in a pH 12 lactate stabilized copper sulfate electrolyte at 55 °C. The electrodeposited Cu2O films are 1.3 µm thick and show pyramidal grains of size up to 2 µm on the surface after a deposition period of 15 mins. Later, these films are subjected to voltage cycling in a potential range of -0.6 V to 0.6 V (vs. Ag/AgCl) in a pH 5 electrolyte comprised of 0.5 M Na2SO4 and 0.1 M K2HPO4 at RT. This causes top 0.5 µm of deposited films to reconstruct to 10-30 nm thick nano-walled porous morphology after 20 cycles of voltage cycling. The voltammogram shows that reconstruction is a concomitant etching of Cu2O as Cu2+ ions along with oxidation to CuO. In fact, a potentiostatic hold at anodic potentials leads to porous CuO. This porous CuO is reduced back to Cu2O during the cathodic part of the voltage cycling. Interestingly, the number of cycles performed during voltage cycling is found to affect the phase purity of the material. The XRD scans reveal that Cu2O films are phase pure only up to 50 cycles. However, phase purity is no longer preserved as Cu impurity is detected in Cu2O films post 50 cycles. A comparison of linear sweep voltammetry (LSV) scans of pristine Cu2O, and CuO thin films show that reduction of Cu2O to Cu is a slow process in this potential range, and hence, Cu-impurity is not observed up to 50 cycles. The bare nanostructured Cu2O film show a photocurrent of -2.0 mA-cm-2 at a potential of 0.3 vs. RHE in a pH 5 media, which is almost 1.5 times of the dense Cu2O. This enhancement in photocurrent is attributed to efficient separation of photogenerated charge carriers in the orthogonal direction, increased electrode-electrolyte contact area, and enhanced light trapping. The photocurrent can further be improved via coating with wide bandgap metal oxide layers such as AZO/TiO2. Such a facile fabrication technique can be utilized to prepare nanostructures of various metal oxides on a large scale for their application in PEC cells and other optoelectronic devices. Figure 1

Chemically deposited p-type MoBiCuS4 thin film for photoelectrochemical cell applications

MoBiCuS4 thin film has been deposited by chemical bath deposition and its structural, morphological, optical and photovoltaic properties have been studied. The XRD shows the presence of mixed phases (monoclinic and orthorhombic) and the crystallite size is found to be about 112 nm. The SEM images picturized the smaller sized irregular and bigger sized rectangular particles, the EDS analysis shows near stoichiometric ratio for the MoBiCuS4 thin film. MoBiCuS4 thin film exbihits higher optical absorption in the visible region and the bandgap is found to be 2 eV. p-type conductivity is noticed in the prepared film. The Photovoltaic (PV) performances of the MoBiCuS4 thin film demonstrates 1.2% photoconversion efficiency with Voc = 0.515 V and Jsc = 3 mA/cm3. This study suggests that the MoBiCuS4 thin film can be used as a absorber material for PV cells.

High-quality Graphitic Carbon Nitride Films Prepared by Close-spaced Thermal Copolymerization for Photoelectrochemical Application

Graphitic carbon nitride (CN) is considered to be an attractive material for application in photoelectrochemical (PEC) water splitting cells and photoelectronic devices. However, it is still a challenge to fabricate high-quality CN films. Herein, high-quality CN films have been synthesized via close-spaced thermal copolymerization of dicyandiamide and cyanuric acid for the first time. This method can not only prepare continuous and uniform CN films that grow directly on a conductive substrate but also effectively adjust the film structure (thickness and morphology).