Photoanode Electrode Research Articles

Creating an intermediate energy band to boost the photoelectrochemical efficiency of TiO2 for solar-driven hydrogen production

The utilization of photoelectrochemical processes for hydrogen generation from water and solar energy offers a promising avenue to replace non-renewable energy sources. Nevertheless, achieving high-performance photoanode electrodes poses a significant challenge. In this study, we present the synthesis cerium and chromium-doped TiO2 (CeCrTiO2) is produced through a simple, scalable, and cost-effective hydrothermal method on a fluorine-doped tin oxide (FTO) substrate. the introduction of Ce and Cr impurities is highlighted for its role in creating an impurity band within CeCrTiO2. This impurity band is instrumental in enhancing the separation and movement of electrons and holes, contributing to the improved performance of CeCrTiO2 as a photoanode in photoelectrochemical applications. Hence, the photocurrent density value of CeCrTiO2 is 4.5 times higher than that of bare TiO2. This suggests that CeCrTiO2 exhibits improved efficiency in generating a photocurrent when exposed to light, indicating enhanced photoelectrochemical performance. The amount of hydrogen produced by CeCrTiO2 is noted to be 4.88 times greater than that of bare TiO2. This highlights the material's effectiveness in harnessing solar energy to drive the water-splitting reaction, leading to a higher yield of hydrogen gas. The synthesis of CeCrTiO2 through a hydrothermal method results in a photoanode with significantly enhanced performance, positioning it as a promising candidate for advancing photoelectrochemical processes aimed at replacing non-renewable energy sources.

Natural dyes (Tithonia diversifolia, Tagetes minuta and Bidens pilosa) sensitized solar cells with reduced graphene based electrodes

The search for suitable alternatives to non-renewable polluting energy sources is a continuous and an active undertaking. There is particular focus towards production of low cost, eco-friendly and more efficient dye sensitized solar cells (DSSCs). Natural dyes DSSCs have the capability of generating green energy at low production cost and hence become a promising class of photovoltaic cells. However, there are inherent problems encountered by the conventional DSSCs including photoanode and cathode related problems such as high cost and electron-hole recombination resulting in a low rate of photoelectric conversion efficiency. In this work, organic dyes from Tithonia diversifolia, Tagetes minuta and Bidens pilosa were used as sensitizers as replacement of synthetic dyes of the conventional DSSCs. The study in addition sought to replace conventional photoanode and cathodes with rGO-TiO2 photo anode and rGO counter electrode. The Tithonia diversifolia has one absorption peak at 665 nm indicating the presence of chlorophyll dye while Tagetes minuta has absorbption peaks at 534 nm suggestive of anthocyanin dye (a flavonoid), 607 nm and 660 nm confirming the presence of chlorophyll a dyes while Bidens pilosa has an absorption peak at 665 nm which again suggests the presence of chlorophyll dye. The tendency of the three natural dyes to absorb in the regions above 650 nm indicates their usefulness for use as dyes for DSSC. The I-V curves of the fabricated natural DSSCs show that when TiO2 is used as the photo anode, Tithonia diversifolia registered a higher efficiency of 0.18 % while Tagetes minuta had the lowest efficiency of 0.08 %. When rGO is incorporated in the TiO2 photo anode, there is an improvement in the solar cell efficiency for all the fabricated DSSCs with Tithonia diversifolia having the highest at 1.56 %. Thus incorporating rGO in the TiO2 photo anode greatly improved the power conversion efficiency of the DSSC. Tithonia diversifolia dye had the highest efficiency which may be attributed to the concentration of the chlorophyll dye.

Coating of CoS on hybrid anode electrode with enhance performance in hybrid dye-sensitized solar cells

Improvement of the power generation performance of dye-sensitized solar cells (DSSCs) remains a key task, as charge transfer and charge separation are efficiently achieved at the photoanode and between the polysulfide electrolyte interface and the counter-electrode. We synthesized the metal sulfides from dithiocarbamate complexes and used them to fabricate a new modified cell by passivating the photoanode electrode with CoS nanoparticles and SnS as photosensitizer in a two-step deposition approach. They were used as FTO-TiO2/CoS/SnS/HI-30/FTO-Pt, known as C-S-1, C-S-2 and C-S-3. SEM images show that the C-S-1 and C-S-2 are uniform, without cracks and have a dense surface morphology covering the surface area. Thus, confirming the successively passivation by CoS and sensitization of SnS, forming FTO-TiO2/CoS/SnS heterostructure. The η of 8.79% and 9.43% are much higher than that of C-S-2, with 0.23% affirm the roles of the Co, Sn and S ratio on both devices. The EIS Nyquist plot for the C-S-2 device shows a semicircle radius smaller than the C-S-1 and C-S-3, which indicates more efficient inhibition of electron/hole pairs and faster transportation of photogenerated charge carriers. The enhanced performance of both devices shows that the passivation of the electrodes ensures that maximum absorption is achieved through a higher absorption coefficient of SnS. Also, both devices reach a steady state within about 200–300 s and remain at the steady state current for a long duration for C-S-1 and C-S-3. The enhanced performance of both devices shows that the passivation of the electrodes ensures that maximum absorption is achieved through a higher absorption co-efficient of SnS.

Construction of a Conductive Polymer/AuNP/Cyanobacteria-Based Biophotovoltaic Cell Harnessing Solar Energy to Generate Electricity via Photosynthesis and Its Usage as a Photoelectrochemical Pesticide Biosensor: Atrazine as a Case Study.

In this research, a cyanobacteria (Leptolyngbia sp.)-based biological photovoltaic cell (BPV) was designed. This clean energy-friendly BPV produced a photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on the gold electrodes. In the cell, the photoanode was first coated with a gold-modified poly 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzamine polymer, P(SNS-Aniline). Thioaniline-functionalized gold nanoparticles were used to provide a cross-link formation with bis-aniline conductive bonds with the conductive polymer using electrochemical techniques. Leptolyngbia sp., one of the cyanobacteria that can convert light energy into chemical energy, was attached to this layered electrode surface. The cathode of the cell was attached to the gold electrode surface with P(SNS-Aniline). Then, the bilirubin oxidase (BOx) enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light, thanks to cyanobacteria, oxidized and split water, and oxygen was obtained at the photoanode electrode. At the cathode electrode, the oxygen gas was reduced to water by the bioelectrocatalytic method. To obtain a high photocurrent from the BPV, necessary optimizations were made during the design of the system to increase electron transport and strengthen its transfer. While the photocurrent value obtained with the designed BPV in optimum conditions and in the pseudosteady state was 10 mA/m2, the maximum power value obtained was 46.5 mW/m2. In addition to storing the light energy of the system, studies have been carried out on this system as a pesticide biosensor. Atrazine biosensing via the BPV system was analytically characterized between 0.1 and 1.2 μM concentrations for atrazine, and a very low detection limit was found as 0.024 μM. In addition, response time and recovery studies related to pesticide biosensor properties of the BPV were also investigated.

Effect of annealing temperature on bismuth vanadate nano thin films for solar cell applications

Bismuth vanadate (BiVO4) has been used as the photoanode electrodes in ferroelectric solar cells owing to its unique combination of properties: a narrow bandgap among ferroelectrics, economic viability, negative conduction band edge, and remarkable stability. The present work explores the fabrication and characterization of BiVO4 thin films prepared via spin coating, with a specific focus on elucidating the influence of the annealing temperature (400–550 °C) on their structural, optical, and photovoltaic properties. From X-ray diffraction (XRD) analysis, it is observed that higher annealing temperatures have promoted the formation of larger grains, enhanced crystallinity, and induced a preferred crystal orientation characteristic of the monoclinic scheelite structure. Tauc plot analysis shows the dependence of the optical band gap on the annealing temperature for BiVO4 thin films. The band gap values have decreased slightly from 2.50 eV at 400 °C to 2.44 eV at 550 °C. This is indicated by the slightly narrowed bandgap, which influences the structure of the material or defect states at higher annealing temperatures. A narrower bandgap allows for the absorption of lower-energy light, potentially improving the light absorption efficiency of BiVO4 thin films in photoanode applications. The influence of annealing temperature on BiVO₄ thin film solar cell performance was investigated further through the analysis of open-circuit voltage (Voc), short-circuit current (Isc) and power conversion efficiency.

Design of a Novel Green Algae‐Based Biological Photovoltaic Cell with High Photocurrent and a Photoelectrochemical Biosensing Approach Utilizing the BPV for Pesticide Analysis in Water

AbstractIn this research, a green alga (Paulschulziapseudovolvox sp.) based biological photovoltaic cell (BPV) was designed. This clean energy‐friendly BPV produced photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on gold electrodes. In the cell, the photoanode was first coated with a gold‐modified poly 4‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)benzamine polymer, (P(SNS‐NH2)). Cytochrome C (Cyt. C) material was used to provide crosslink formation with bis‐aniline covalent bonds with the conductive polymer using electrochemical techniques. Paulschulziapseudovolvox sp., one of the green algae that can convert light energy into chemical energy, is attached to this layered electrode surface. The cathode of the cell is attached to the gold electrode surface with poly 4‐(4HDithieno[3,2‐b : 2′,3′‐d]pyrrole‐4‐yl)aniline (P(DTP‐Aryl‐Amine)). Then, the bilirubin oxidase enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light thanks to green algae, oxidizes and splits water, and oxygen is obtained at the photoanode electrode. At the cathode electrode, the oxygen gas is reduced to water by the bio‐electro‐catalytic method. To obtain high photocurrent from the BPV, necessary electrochemical and chemical optimizations were made during the design of the system to increase the amount of electrons that were transferred and fasten its transfer rate. While the photocurrent value generated by the designed BPV in optimum conditions and in the pseudo‐steady state is 10 mA/m2, the maximum power value obtained is 46.5 mW/m2. In addition to the production of the green algae‐based BPV generating highly efficient electricity which is the main of target of this study, some studies have also been carried out to show whether this system can be used as a pesticide biosensor. Atrazine and diuron biosensing via the BPV system was analytically characterized and recovery and interference studies related to pesticide biosensor property of the BPV were also investigated.

Improvement of the photoelectric dye sensitized solar cell performance using Fe/S–TiO2 nanoparticles as photoanode electrode

A sulfur nanoparticles-incorporated iron-doped titanium oxide (Fe/TiO2) with different ratio was successfully synthesized by photolysis method and utilized as effective photoanode in dye sensitized solar cell (DSSC) application with N719 dye. The photolysis method was contained the irradiation of the Fe, S and Ti mixture solution with 15 W source irradiation, and then calcined the formed precipitate. The DSSCs fabricated with Fe/S–TiO2 photoanode appeared an improved solar-to-electrical energy conversion efficiency of 6.46, which more than pure TiO2 (3.43) below full sunlight illumination (1.5 G). The impact of Fe content on the total efficiency was also inspected and the Fe content with 6% S–TiO2 was found 5 wt%. Due to the improved the efficiency of solar cell conversion of Fe/S–TiO2 nanocomposite, it should be deemed as a potential photoanode for DSSCs with high performance.

3D TiO2 modified with reduced graphene embed into polyvinyl alcohol: photoanode electrode for oxygen evolution reaction

The photocatalytic hydrogen production from water splitting using solar energy is one of the promising trend research topics within the scope of green energy production. A photoelectrochemical set up consists of photoelectrode materials that directly uses photon energy convers water to hydrogen and oxygen. The photoelectrodes are photoanode and photocathode materials n-type and p-type semiconductor, respectively. In this study, the 3D TiO2 photoanode surface was modified by coating it with reduced graphene (rG) added polyvinyl alcohol (PVA) gel. PVA synthetic polymer with thermal stability, mechanical stability and low cost was preferred to provide distribution of rG material on 3D TiO2 active surfaces. In this context, different amounts of rG (2.5, 5, 10 and 20%, based on polymer weight) impregnated with PVA gel coated on the 3D TiO2 semiconductor surface were investigated. The solar light absorption behaviour and molecular interactions of the different amounts of rG in PVA on 3D TiO2 semiconductor were monitored by UV-vis and Raman spectrometer. A photocatalytic performance of photoelectrodes were conducted by Electrochemical Impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and chronoamperometric measurement under 100 mW cm-2 solar light. Raman spectrum showed dispersion of RG in PVA. EIS measurement showed that the polarization resistance (Rp) increased in 3D TiO2 with only PVA coating, while the addition of rG to PVA caused a decrease in Rp at the semiconductor/electrolyte interface under sunlight. Furthermore, LSV and chronoamperometric measurement concluded that the increased amount of rG added to PVA increased the photoresponse of 3D TiO2 up to the limit rG value.

A Perovskite Photovoltaic Mini-Module-CsPbBr3 Photoelectrochemical Cell Tandem Device for Solar-Driven Degradation of Organic Compounds.

Recently, halide perovskites have been widely explored for high-efficiency photocatalysis or photoelectrochemical (PEC) cells. Here, in order to make an efficient photoanode electrode for the degradation of pollutants, concretely 2-mercaptobenzothiazole (MBT), nanoscale cesium lead bromide (CsPbBr3) perovskite was directly formed on the surface of mesoporous titanium dioxide (meso-TiO2) film using a two-step spin-coating process. This photoelectrode recorded a photocurrent of up to 3.02 ± 0.03 mA/cm2 under standard AM 1.5G (100 mW/cm2) illumination through an optimization process such as introducing a thin aluminum oxide (Al2O3) coating layer. Furthermore, to supply high voltage for efficient oxidation of MBT without an external bias, we developed a new photovoltaic/PEC tandem system using a methylammonium lead iodide (MAPbI3) based mini-module consisting of three solar cells interconnected in series and confirmed its successful operation. This approach looks very promising due to its applicability to various PEC reactions.

Preparation and Characterization of ZnO NWs/Graphene Nanocomposite as an Effective Photoanode Electrode for Improving the Performance of the Dye-Sensitized Solar Cells

In the present study, DSSCs were fabricated using pure ZnO NWs and ZnO NWs/Graphene nanocomposite as photoelectrodes. Graphene was incorporated into pure ZnO NWs through a cost-effective Hydrothermal Process to act as an electrical charge carrier. J-V curve of prepared nanocomposite was recorded with a light intensity of 100 mW.cm-2. The created nanocomposites were thoroughly investigated by using different electrical and structural characterization techniques such as SEM, XRD, and J-V characteristics. According to SEM examination, the ZnO NWs/graphene composite-based electrode has more porosity than the electrode made using pure ZnO NWs, which will increase the surface area and the amount of dye that can be absorbed. From the graphene advantages the reduced internal resistance and electron recombination loss, these properties allow electrons to transfer to the collection electrode efficiently. Based on these benefits, the ZnO NWs/Graphene nanocomposite photoanode with thickness of 965.11 nm that was used in the DSSC2 was demonstrated a Jsc of 19.50 mA.cm-2 and conversion efficiency of 9.829053%, which opposite to the result of the DSSC1 without graphene. These results can be encouraged for future improved optoelectronic devices.

Construction of a novel Cu1.8S/NH2–La MOFs decorated Black-TNTs photoanode electrode for high-efficiently photoelectrocatalytic degradation of 2, 4-dichlorophenol

Photoelectrocatalysis (PEC) has long been regarded as an efficient and green method to eliminate various organic pollutants from wastewater. However, the lack of highly photoelectrocatalytic active and stable electrodes limits the development of the PEC technologies. Herein, a novel hierarchical photo-electrode with hollow Cu1.8S/NH2–La MOFs decorated black titanium dioxide nanotubes (Cu1.8S/NH2–La MOFs/Black TNTs) was fabricated by a two-step water-heating method. The prepared photoelectrode was used to degradation of 2, 4-dichlorophenol (2, 4-DCP). Analysis of photoelectrocatalytic degradation process of 2, 4-DCP was evaluated using UV–Vis absorption spectroscopy and the main degradation paths were analyzed by LC-MS. The results showed that 99.3% of the pollutant could be rapidly degraded within 180 min. Furthermore, the Cu1.8S/NH2–La MOFs/Black TNTs photoelectric pole exhibited excellent stability after 15 cycling experiments.

Fabrication, characterization, and photovoltaic performance of titanium dioxide/metal-organic framework composite

The titanium dioxide-metal-organic framework (TiO2−MOF) composite was prepared using the sol-gel method for photovoltaic applications. Raman analyses showed the presence of MOF clusters in the TiO2 sol-gel network. Using the Brunauer-Emmett-Teller method, the resultant composite material exhibited a surface area of 111.10 m2g−1 as compared to the surface area values of 262.90 and 464.76 m2g−1 for TiO2 and MOF, respectively. The small optical band gap values of 2.63 for direct electronic transition and 2.70 eV for indirect allowed electronic transition in TiO2/MOF composite were observed using ultraviolet-visible supported by cyclic voltammetry (CV). The chronoamperometry (CA) results showed the current drop of 0.21 mA observed at 0.025 s for TiO2 and the current drop of1.00 mA for MOF and 1.4 mA for TiO2−MOF composite at 0.3 s. The stability of the composite was achieved through the synergistic effect of MOF on TiO2 which resulted in a high current density. Electrochemical impedance spectroscopy showed a fast electron transfer as well as high ionic conductivity. The overall power conversion efficiency of 0.722% along with a photocurrent density of 0.46 mA cm−2 was achieved for the composite. The approach proposed in this work is facile and can be used for the large-scale fabrication of efficient and flexible photoanode electrodes for photovoltaic applications.

Some Distinct Attributes of ZnO Nanorods Arrays: Effects of Varying Hydrothermal Growth Time

This study investigates the growth time effect on the structural, morphological, optical, and photoelectrochemical characteristics of highly oriented ZnO nanorod arrays (ZNRAs). The nanorod arrays were grown on ITO substrates using the unified sol-gel spin coating and hydrothermal techniques. ZnO nanoparticles (ZNPs) were synthesized using the sol-gel spin coating method. In contrast, the hydrothermal method was used to grow the ZnO nanorods. The hydrothermal growth time investigated was between 4 and 12 h. The synthesized ZNRAs were used as the photoanode electrodes to investigate their photoelectrochemical (PEC) electrode potency. The as-prepared ZNRAs were characterized using various analytical tools to determine their structures, morphologies, optical, and photoelectrochemical traits. EDX spectra showed the presence of uncontaminated ZnO chemical composition, and FTIR spectra displayed the various functional groups in the samples. A rod-shaped ZnO nanocrystallite with mean lengths and diameters of 300–500 nm and 40–90 nm, respectively, is depicted. HRTEM images indicated the nucleation and growth of ZNRAs with a lattice fringe spacing of 0.26 nm and a growth lattice planer orientation of [002]. The optimum ZNRAs (grown at 8 h) as photoelectrode achieved a photoconversion efficiency of 0.46% and photocurrent density of 0.63 mA/cm2, that was 17 times higher than the one shown by ZNPs with Ag/AgCl as the reference electrode. Both values were higher than those reported in the literature, indicating the prospect of these ZNRAs for photoelectrode applications.

UV/H2O2 degradation of diclofenac in a photocatalytic fuel cell

The purpose of this work was to construct an integrated reactor which could photoelectrocatalytically generate hydrogen peroxide under solar radiation and simultaneously degrade a recalcitrant pollutant by the UV/H2O2 process. Diclofenac has been chosen as water soluble model pollutant. Hydrogen peroxide has been produced by atmospheric oxygen reduction in a photocatalytic fuel cell. The cell comprised a transparent photoanode electrode bearing a combined CdS/TiO2 photocatalyst and a carbon cloth cathode bearing nanoparticulate carbon without any other electrocatalyst. Diclofenac was dissolved in the cathode compartment where hydrogen peroxide was generated and the pollutant was degraded by UV radiation support. Degradation was monitored by UV–Vis spectrophotometry and by high performance liquid chromatography. The results show that an integrated reactor functionality is realistic and effective and it provides an alternative route for sustainable operation aiming at environmental remediation.

Electrical Characterization and Efficiency Enhancement of Dye Sensitized Solar Cell Using Natural Sensitizer and TiO2 Nanoparticles Deposited by Electrophoretic Technique

This article concerns the use of anthocyanin, mallow and their mixture as a low-cost natural dyes to sensitize the photo-anodes of dye sensitized solar cells (DSSCs) based on titanium dioxide (TiO2) layers, and investing their effect on the electrical performance of the realized cells. In fact, different layers of porous titanium dioxide (TiO2) were deposited on fluorine-doped tin oxide glass (FTO) via the electrophoretic deposition (EPD) technique, and then sensitized with natural dyes to form the photo-anode electrode for the DSSC. Four DSSCs are manufactured: three cells, each one is formed by a TiO2 single layer and a cell formed by two TiO2 layers. An electric model, with five parameters based on of the Newton–Raphson algorithm (NR), was used to extract the electrical parameters of the cell and establish a comparative study between simulated and experimental current–voltage characteristic ( J – V ). An improvement of short-circuit current and efficiency was obtained for the DSSC with two layers of TiO2 and sensitized with the mixture of mallow and anthocyanin. Indeed, an increase of short circuit current from 0.34 to 1.98 mA/cm2 was observed and the efficiency reached 0.58%. This increase was more confirmed by external quantum efficiency (EQE). Nevertheless, after 96 hours under standard lighting at room temperature of 25 °C, a degradation of the efficiency of the cell with a rate value of 24% was noted.

Decreasing the charging voltage of a zinc-air battery using a bifunctional W:BiVO4/V2O5 photoelectrode and sulfite as a sacrificial agent

The promising potential of rechargeable Zn-air battery as energy storage technology is followed by relevant limitations, such as its high charging overpotential that restricts its feasibility. In such a way, replacing the battery electrocatalyst for a photoelectrode can offer a double advantage compared to conventional rechargeable metal-air batteries: (i) to act more efficiently in the oxidation reaction involved in the charging process, and (ii) to reduce the charging bias using sunlight. Herein, we report for the first time a BiVO4-based photoelectrode as the bifunctional electrode of a zinc-air battery. The novel photoelectrochemical battery consisting of a W:BiVO4/V2O5 photoelectrode in a sulfite solution and a Zn electrode in an alkaline medium can have its charging voltage reduced up to 1.2 V under visible-light illumination. In discharge mode, where the photoanode electrode plays the role of air electrode, the system can deliver power with an open-circuit potential of 1.1 V.

Enhanced photovoltaic performance of dye‐sensitized solar cell based on ZnO nanoparticles and ZnO/graphene nanocomposites

AbstractFor clean, inexpensive, and renewable power source, dye‐sensitized solar cell (DSSC) has attracted more attention in recent decades. DSSC faces various challenges that lead scientists to further research. In this study, the efficiency of DSSC was improved through the development of a new ZnO nanoparticles and ZnO/graphene nanocomposite as a photoanode electrode and poly(3,4‐ethylenedioxythiophene) (PEDOT), PEDOT/multi wall carbon nanotube (MWCNT), and Pt as a counter electrode. Synthesized samples were characterized by field emission scanning electron microscopy, X‐ray powder diffraction, diffuse reflectance spectroscopy, brunauer emmett teller (BET)‐barrett joyner halenda (BJH), and ultraviolet–visible spectroscopy (UV–Vis) spectroscopy. Various DSSC with different photoanode and counter electrode were fabricated in this study. Results showed that graphene has much impact on the performance of DSSC. ZnO/graphene and Pt‐based solar cell showed an open circuit voltage of 0.78 V and the fill factor 0.75 and 11.53 conversion efficiency under the one sunlight irradiation. For the ZnO/graphene and PEDOT/MWCNT case, open circuit voltage of 0.65 V and the fill factor 0.83 and 5.542 conversion efficiency was measured.

In-situ fabrication a thin-film nanocomposite photo-anode electrode for the dye-sensitized solar cell

Here, the performance of dye-sensitized solar consisting of the TiO2 anatase phase of nanoparticles and its nanocomposite (TiO2/G) were successfully fabricated via the electrophoretic method as thin films on the ITO conductive glass. Thin films were characterized by the X-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), Diffuse Reflectance Spectroscopy (DRS), and Raman spectroscopy. All of these techniques have confirmed the formation of nanocomposite when added the graphene sheets with changing in the properties of titanium dioxide nanoparticle. It can be noticed the peak in (002) which attributes to the graphene in TiO2/G. The new peaks that appeared in FTIR, and the bandgap reduced to be about 2.9 eV. Thus, the introduction of graphene sheets to the thin film of TiO2 photo-anode electrode via the solvo-electrochemical route is an effective method to improve the performance of the ITO/TiO2 thin film DSSC, which increases the short current density and increases the conversion efficiency of dye-sensitized solar cell from the 2.14 to 2.53 % after employed the thin-film titanium dioxide modified photo-anode.

Synthesis and Photoelectrochemical Activity of α‐Fe2O3−CdFe2O4 Hybrid Structure for the Water Oxidation Reaction

AbstractThe electrochemical properties of spinel ferrites have been studied since the 1970s after the pioneering discovery of water electrolysis by using TiO2 as the photoanode in a photoelectrochemical cell. Several approaches have been developed to fabricate ferrites of different sizes and shapes but most of these methods suffer from several disadvantages, such as the difficulty to produce the ferrite in a thin layer form or on top of another (pre‐prepared) structure as a second layer. Moreover, the formation process requires calcination at high temperatures, and the electrode fabrication requires an additional assembly method. Herein, a CdFe2O4 ferrite was formed via chemical vapor deposition of a single‐source precursor directly on a hematite structure followed by an annealing process. This thermal treatment simultaneously achieves both activation of the hematite and the formation of CdFe2O4. Three different iron oxide (rectangular, nanobelt, and mesoporous) structures were examined as photoanode electrodes. The maximum current at 1.65 V vs. RHE of the mesoporous film was more than two times higher than the rectangular and the nanobelt films. Therefore, iron oxide with mesoporous structures was used to form the hybrid structure of α‐Fe2O3−CdFe2O4. The hybrid structure presents stable and high photocurrent density (about 20 % enhancement in the measured maximum current density at 1.65 V vs. RHE).

Graphene sheets incorporation in ZnO nanostructure thin film for enhancing the performance of DSSC

In the present work, the zinc oxide nanoparticle and its composite have prepared with the graphene as a photoanode electrode as well as synthesizing an excellent thin film from the PEDOT: PSS, which is conductive polymer loading with MWCNT as an auxiliary electrode for the DSSC. The photoanode characterized using ( XRD, FTIR, Raman spectroscopy, BET-BJH, and UV-DRS). The FESEM and AFM performed to study morphology and structure of ZnO, ZnO/Graphene, and PEDOT: PSS/MWCNT thin films. The results confirm a successful fabrication of the thin films on the ITO by using the electrophoretic deposition method as well the added of graphene reduced the band gap close to 3.0eV. Moreover, the PEDOT: PSS/MWCNT nanocomposite based an auxiliary electrode offered high electrical conductivity, which enhanced the photovoltaic values of DSSC. The BET-BJH results demonstrated of the synthesis of zinc oxide nanoparticles at the surface area 6.66 m2/g and pore size 1.42 m3/g.