Electrodes For Dye-sensitized Solar Cells Research Articles

NiCo2S4 nanotube arrays grown in situ on Ni foam as a low-cost counter electrode for dye-sensitized solar cells

In recent researches of catalytic materials, ternary sulfides have shown excellent electrochemical performance. In this study, NiCo2S4 nanotube arrays were grown in situ on nickel foam by using a two-step hydrothermal method, and optimized the growth morphology of the nanotube arrays by adjusting the raw material concentration. The Ni foam is selected as a suitable conductive substrate, combining its excellent chemical properties and nanostructures, finally a NiCo2S4 nanotube/Ni foam with outstanding catalytic properties is formed. The photoelectric conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs) with NiCo2S4 nanotubes/Ni foam counter electrode (CE) has reached 8.29%, which is exceeding that of Pt CE (7.48%), indicating that NiCo2S4 nanotubes/Ni foam CE has a bright development prospect.

Enhanced properties of low-cost carbon black-graphite counter electrode in DSSC by incorporating binders

Carbon-based counter electrodes of dye-sensitized solar cells (DSSCs) such as carbon black-graphite composite (CB/Gr) have received unprecedented interest in recent years due to their ease of fabrication, good corrosion resistance, and low cost compared to platinum (Pt) electrodes. However, the poor surface adherence between the carbon counter electrodes (CE) and FTO substrate, low surface area, and poor inter-particle connection between the carbon materials have consistently become a major challenge. In order to overcome these issues, we have fabricated CB/Gr by incorporating binders of titanium (IV) isopropoxide (TTIP), and zirconium (IV) dioxide (ZrO2) as the counter electrodes for the DSSC. The performance of the CE is characterized by four-point probe conductivity measurement, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and current density voltage (J-V) characteristics. The results revealed that incorporating binders to the CB/Gr has improved the series resistance (RS) and charge transfer resistance (RCT), which enhances the short-circuit current density (JSC), fill factor (FF), and the power conversion efficiency (PCE) of the device. The TTIP binder in CB/Gr CE exhibited superior performance in DSSC is largely attributed to the formation of TiO2 in situ with small particle size of about 100 nm, leading to enhanced intimate contact between the carbon materials, high surface area, and better surface adherence between counter electrode and the FTO substrate. Our findings, thereby, offer the possibility to engineer and optimize the energy levels of CE in an effort to develop a high-performing DSSC counter electrode.

Titanium Nitride Nanoflower Buds as Pt-Free Counter Electrodes for Dye-Sensitized Solar Cells

Titanium Nitride Nanoflower Buds as Pt-Free Counter Electrodes for Dye-Sensitized Solar Cells

Sb2S3 entrenched MWCNT composite as a low-cost Pt-free counter electrode for dye-sensitized solar cell and a viewpoint for a photo-powered energy system

The current research interest is to use Sb2S3 entrenched Multi-Walled Carbon Nanotubes (MWCNT) composite as Pt-free counter electrode in dye-sensitized solar cells (DSSCs) and also to test its usage as a supercapacitor. Hence here, Sb2S3 nanorods with different concentrations of MWCNT have been synthesized by facile microwave irradiation technique and are used as a counter electrode in Pt-free DSSCs and also tested for supercapacitance. Crystalline structure, shape, and quantum states have been elucidated using XRD, TEM, and XPS spectra, respectively. Among all, Sb2S3/CNT30 composite counter electrode delivers the highest Power Conversion Efficiency (PCE) of 5.02% with a short circuit current (JSC) of 12.68 mA cm−2 and open-circuit voltage (VOC) of 0.68 V. The improvement observed is due to the lower peak-to-peak separation (Epp), higher exchange current density (J0) and lower charge transfer resistance (RCT). The obtained PCE is compared with the standard Pt-based counter electrode (PCE~5.8%) and discussed. This composite is also found to be a suitable material for the supercapacitor. Among the electrodes, Sb2S3/CNT100 exhibits the highest specific capacity of 228 C g−1 with 1 Ag−1 with the capacitive retention of ~92.5% over 1000 charge-discharge cycles, which also reveals its ability for energy storage. The excellent capacitive and photovoltaic output highlights the promise of Sb2S3/MWCNT for photo-supercapacitor devices.

Performance of Dye Sensitized Solar Cells (DSSCs) with ZnO Nanorod Electrode in Different Seed Solution

Studies of comparing the performance of photoelectrode for dye-sensitized solar cells (DSSCs) continue to be carried out and developed. The ZnO nanorods as an electrode for DSSCs have been shown to have high electron collection due to the capability of electron photoexcitation and increased electron transport. Various methods of making ZnO nanorods have been studied and developed. However, the method requires controlled conditions under high temperature and pressure, thus limiting the commercialization of ZnO nanorods. Therefore, the seed solution-based hydrothermal method was chosen in the ZnO nanorod deposition process because it is an effective method, low-cost and easier fabrication process. The method of growing ZnO nanorod was carried out with three times of growing for 6 hours. ZnO nanorod was synthesized using different seed solutions, namely sample 1 and sample 2 by using methoxy and isopropanol, respectively. In this work, the SEM image shows the growth of ZnO nanorods vertically aligned on the FTO substrate and resulted in a smaller diameter for the isopropanol seed solution. The smaller diameter of the ZnO nanorod provides a larger surface area then increasing the total amount of dye attached to the ZnO nanorod and improve the photovoltaic performance.

Fabrication and Properties of Graphene Electron Multiple Transporting Layers for Dye-Sensitized Solar Cell

To investigate the optimal working electrode for dye-sensitized solar cells (DSSCs), the traditional TiO2 film is modified by adding an electron transporting layer of graphene. Different layers of TiO2/graphene/TiO2 stacks on the FTO substrate are analyzed. The experimental results show that the TiO2/graphene/ TiO2/graphene/TiO2 (TGT2) structure has higher dye loading, which means that more dye molecules can increase the light absorption. In the electrochemical impedance spectroscopy (EIS) analysis, the TGT2 structure has a lower interfacial resistance ( R ct2) of 2.35 Ω at the TiO2/dye/electrolyte interface and a higher electron lifetime (τe) of 64.28 ms. This result represents that the graphene material exerts its properties of good conductivity and high charge carrier mobility to reduce the interfacial resistance and enhance the electron transport capability. The DSSCs with TGT2 structure working electrode has the short circuit current density ( J SC) of 10.87 mA/cm2 and photovoltaic conversion efficiency (η) of 4.47%. In this study, the working electrode of DSSC is successfully modified by using a TGT2 structure, with an improved efficiency of 10.6% and short circuit current density ( J SC) of 17.7% higher than that of the TiO2 working electrode.

Preparation of Cu3SnS4 film with single ceramic target magnetron sputtering for Pt-free counter electrode of dye-sensitized solar cell

Preparation of Cu3SnS4 film with single ceramic target magnetron sputtering for Pt-free counter electrode of dye-sensitized solar cell

Nickel foam supported Pt as highly flexible counter electrode of dye-sensitized solar cells

In this paper, Pt nanoparticles are deposited on nickel foam by the mild displacement reaction occurring at room temperature. Thus prepared nickel foam supported Pt is used as efficient and highly flexible counter electrode of dye-sensitized solar cells (DSSCs), the performance of which can be enhanced by simply prolonging the reaction time. The results denote that when the reaction time is just 40 min, the nickel foam supported Pt has exhibited better catalytic activities than the commonly used polyethylene naphthalate polymers supported Pt. The deposition of Pt is investigated by the scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy and UV–Vis spectra, and the catalytic activities of fabricated flexible Pt counter electrode are verified by electrochemical impedance spectra and cyclic voltammetry curves. The approach proposed here is facile and can be used for the large scale fabrication of efficient flexible counter electrode in DSSCs.

Effect of electropolymerization duration on the structure and performance of polypyrrole/graphene nanoplatelet counter electrode for dye-sensitized solar cells

Effect of electropolymerization duration on the structure and performance of polypyrrole/graphene nanoplatelet counter electrode for dye-sensitized solar cells

Highly ordered mesoporous Co3O4 cubes/graphene oxide heterostructure as efficient counter electrodes in dye-sensitized solar cells

Highly ordered mesoporous Co3O4 cubes/graphene oxide heterostructure as efficient counter electrodes in dye-sensitized solar cells

Cobalt and Carbon Complex as Counter Electrodes in Dye-Sensitized Solar Cells

We developed cobalt and carbon complex materials as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) to replace conventional platinum (Pt) CEs. Co12 and Co15, both of which are basic cobalt derivatives, showed good redox potential with a suitable open-circuit voltage (VOC); however, their poor electrical conductivity engendered a low short-circuit current (JSC) and fill factor (FF). Mixing them with carbon black (CB) improved the electrical conductivity of the CE; in particular, JSC and FF were considerably improved. Further improvement was achieved by combining cobalt derivatives and CB through thermal sintering to produce a novel CoCB material as a CE. CoCB had good electrical conductivity and electrocatalytic capability, and this further enhanced both JSC and VOC. The optimized device exhibited a power conversion efficiency (PCE) of 7.44%, which was higher than the value of 7.16% for a device with a conventional Pt CE. The conductivity of CoCB could be further increased by mixing it with PEDOT:PSS, a conducting polymer. The device’s JSC increased to 18.65 mA/cm2, which was considerably higher than the value of 14.24 mA/cm2 for the device with Pt CEs. The results demonstrate the potential of the cobalt and carbon complex as a CE for DSSCs.

Ultrathin layered MoS2 and N-doped graphene quantum dots (N-GQDs) anchored reduced graphene oxide (rGO) nanocomposite-based counter electrode for dye-sensitized solar cells

Numerous inorganic and organic counter electrodes (CEs) have been fabricated for dye-sensitized solar cells (DSSCs) instead of platinum (Pt) CE. However, MoS2 and carbon nanocomposite have played an important role in CEs due to their superior electrochemical properties and high chemical stability. N-doped graphene quantum dot (N-GQD) @ MoS2 @ reduced graphene oxide (rGO) nanocomposite was synthesized by the two-step hydrothermal method. The morphology of as-synthesized nanocomposites was studied using field emission scanning electron microscope (FE-SEM) and scanning transmission electron microscopy (STEM). It confirms the formation of sphere-like MoS2 composed of nanosheets on the surface of rGO sheets. The N-GQD@MoS2@rGO composites confirmed the presence of MoS2, rGO, and N-GQD by X-ray diffraction (XRD) and Raman spectra. The chemical composition and purity of N-GQD@MoS2@rGO was examined by the X-ray photoelectron spectroscopy analysis technique. The electrochemical property of the as-fabricated CEs was studied by cyclic voltammetry (CV) analysis by using the iodine-based electrolyte. The N-GQD@MoS2@rGO shows the superior catalytic property due to more electrochemical active site and electrical conductivity property of rGO and MoS2. The DSSCs device assembled with as-fabricated CEs and their photovoltaic power conversion efficiency (η) of MoS2 was 2.01%, MoS2@rGO was 3.92%, N-GQD@MoS2 was 3.53%, N-GQD@MoS2@rGO was 4.65%, and Pt was 5.17%.

Impedance spectroscopy of nanostructured ZnO morphologies

In this study, four nanostructured ZnO morphologies, nanoribbons, nanorods, nanoparticles, and nanoshuttles, were synthesized at annealing temperatures of 300 °C, 500 °C, and 700 °C. Structural properties were studied by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction Spectroscopy (XRD), and Differential Scanning Calorimetry (DSC). Optical properties were analyzed by UV–Visible Spectroscopy and Photoluminescence (PL). Electrical transport properties were studied by the Cole–Cole plot technique and electrical resistivity. From the impedance spectroscopy analysis, we extracted the carrier lifetime, the RC time constant, and grain and grain boundary parameters in each morphology. We observed that resistance decreased with increasing temperature in all samples in general, while nanorods, nanoshuttles, and nanoribbons showed well-defined semicircle profiles due to grain and grain boundaries at higher temperatures. From wettability studies, we obtained that surface with ZnO nanoparticles has hydrophobic properties, while nanorods, nanoribbons, and nanoshuttles resulted in a superhydrophobic surface. The optimum ZnO nanomorphology based on impedance studies can be used for developing electrodes for dye-sensitized solar cells.

Liquid phase deposition/anodizing of TiO2 nanotube working electrode for dye-sensitized solar cells

With a high carrier transfer rate, anodizing TiO2 nanotubes (TNTs) are often used as the working electrode in dye-sensitized solar cells (DSSCs). However, the TNT length is restricted by the thickness of the Ti foil, which in turn limits the dye adsorption efficiency of the working electrode. To combat this problem, this study used liquid-phase deposition (LPD) to fabricate a TiO2 film on anodizing TNT. LPD allows for more rapid and even deposition of TiO2 films on the anodizing TNT structure than does vacuum deposition. Analysis revealed that LPD-TiO2 films fabricated at 3.33 nm/s increased the length of the TNT from 17.76 to 24.80 μm, and the dye adsorption capacity rose from 9.8 × 10−7 to 1.07 × 10−6 mol/m3. Testing confirmed that the photoelectric conversion efficiency of the DSSC device of the LPD/anodizing TNT increased from 2.43% to 2.85%, that the interface impedance of the DSSC device (R2) decreased from 132 to 41.5 Ω, and that the electron lifetime (τe) increased. In sum, the LPD-TiO2 film increased the thickness, dye adsorption efficiency and reduced the oxygen vacancies in the anodizing TNT; in other words, the coating effectively enhanced the photoelectric conversion properties of the DSSC device of the working electrode.

A DFT study on electrocatalytic performance of 12CaO·7Al2O3 (C12A7) with electrolytic LiI applied in DSSCs

The electrocatalytic properties of C12A7 materials were improved by hydrated, protonated, and hydroxylated interactions. Geometric structures, charge transfers, thermodynamic quantities and electronic density of states of the studied reactions were performed using DFT calculations. Based on these calculations, a hydroxylation reaction on C12A7 shows more interesting structures because of its configuration’s shape. According to the band gap, the hydroxylated–C12A7 form is a candidate electrocatalytic material for electrolysis reactions. In this investigation, improved C12A7 with hydroxylation was utilized as an electrocatalytic material for redox reactions with LiI and applied as a counter electrode in dye-sensitized solar cells (DSSCs). The calculated results reveal that the hydroxylated–C12A7 structure can undergo electrocatalytic reactions in DSSC counter electrodes. The result may be useful for further design and experimental improvement of an electrocatalytic mechanism to enhance their electrode properties.

Graphene wrapped NiSe2 nanocomposite-based counter electrode for dye-sensitized solar cells (DSSCs)

Strengthening electrical conductivity of metal combine with carbon based content is benefit for improving activity of photovoltaic system. Herein, we designed a NiSe2/graphene hybrid, constructed by NiSe2 nanocrystals homogeneously anchored on the graphene nanosheets, is fabricated through a facile one-step hydrothermal method. The crystallographic, morphology, optical and textural properties of samples were analyzed by XRD, SEM, TEM, UV, PL and BET analysis. The fabricated NiSe2/graphene applied as a counter electrode (CE) of dye-sensitized solar cells (DSSCs) for the first time, which displays remarkable catalytic activity in the reduction of I3−. The DSSC with a NiSe2/graphene CE produces higher power conversion efficiency (10.6%) than bare NiSe2 CE (6.04%) under the same conditions. Hence, NiSe2/graphene products have great potential applications as the CE of DSSCs and can be an efficient method to substitute for Pt in DSSCs.

Adhesion improvement of polyaniline counter electrode in dye-sensitized solar cell using bio-based alkyd

Recently, polyaniline (PAni) has shown promising performance in dye-sensitized solar cell (DSSC) but PAni exhibits poor adhesion on fluorine-doped tin oxide (FTO) substrate. In this study, a bio-based alkyd PAni counter electrode (CE) was developed by modifying PAni with a palm oil-based alkyd (POBA) to improve the adhesion of PAni on FTO substrate. PAni-AOT was synthesized via chemical oxidative polymerization using dioctyl sodium sulfosuccinate (AOT) as dopant, while POBA was prepared through alcoholysis and polycondensation reactions. The preparation of PAni-AOT modified with POBA (PAni-AOT/POBA) films was investigated using different reactive diluents such as methyl acrylate, methyl methacrylate and cyclohexyl methacrylate (CMA) under UV curing method. Chemical structures of PAni-AOT, POBA and PAni-AOT/POBA were confirmed by Fourier transform infrared (FTIR), ultraviolet–visible (UV–Vis) and proton nuclear magnetic resonance (1H NMR) analyses. PAni-AOT/POBA films, with CMA diluent, recorded the lowest curing time of 5 minutes with high electrical conductivity of 6.49 × 102 Scm − 1 and best adhesion of 5B on FTO substrate. Conductivity and adhesion are crucial factors that contribute to high power conversion efficiency (PCE) of DSSC. The fabrications of DSSC were prepared using titanium dioxide photoanode, ruthenium dye, PAni-AOT/POBA as CE and iodolyte electrolyte. A moderate PCE of 0.65% in DSSC was successfully obtained. These results confirmed that PAni-AOT/POBA as CE can potentially be applied as cost-effective and bio-based materials used for DSSC study.

Solution processed Cu2ZnSnSe4 nanoink for inexpensive Pt-free counter electrode in dye-sensitized solar cells

Morphology controllable Cu2ZnSnSe4 (CZTSe) nanoparticles (NPs) were successfully synthesized through hot injection method using oleic acid as solvent. The crystalline phase of the as-synthesized CZTSe NPs was confirmed with powder X-ray diffraction (XRD) and Raman results. The optical absorption spectra of CZTSe NPs exhibit a band gap of 1.21 eV. SEM analysis showed interconnected nanoflake-like morphology with higher surface area. The solid-state ligand exchanged CZTSe thin film without any toxic selenization process was used as counter electrode (CE) in dye-sensitized solar cells (DSSCs). The electrocatalytic activity of the CZTSe thin film for the reduction of iodide (I3−/I−) electrolyte was studied through cyclic voltammetry (CV) measurements. The DSSCs with ligand exchanged CZTSe CE exhibit an efficiency of 3.9% under 1 sun illumination, which is found to be higher than the Pt-based DSSC (3.5%) prepared in the same lab.

Highly efficient MoS2/rGO electrocatalysts for triiodide reduction as Pt-free counter electrode for dye-sensitized solar cells

Developing large-scale and high-efficient electrocatalysts based on earth-abundant element is urgent to promote the development of dye-sensitized solar cells (DSSCs). As an attractive approach, ultrasonic spray pyrolysis (USP) could prepare large-scale micro-nano structured catalytic materials, whereas these spheroidal particles usually could not conduct electron well with each other, thus inhibits catalytic activity. Herein we introduce reduced graphene oxide (rGO) to improve the conductivity and catalytic performance of MoS2 synthesized by USP. The MoS2/rGO hybrids combines the abundant active sites of MoS2 and excellent conductivity of rGO, reduces the CE/electrolyte interfacial electron transfer resistance, increases the contact of film with substrate, thus exhibits decreased Rct (1.00 Ω), improved efficiency of 8.53% and enhanced stability. Due to the high yield and good reproducibility of USP method, the large-scale (10 cm × 10 cm) and flexible MoS2/rGO CE shows good consistency of catalytic activity and bending resistance. These results demonstrate that this synthetic approach and introducing of rGO offers a scalable and simple strategy for synthesizing efficient materials in various electrochemical applications.

Time-Optimized Hydrothermal Synthesis of Nano-WO3 for Application as Counter Electrode in Dye-Sensitized Solar Cell

Time-Optimized Hydrothermal Synthesis of Nano-WO3 for Application as Counter Electrode in Dye-Sensitized Solar Cell