Counter Electrode For Solar Cells Research Articles

Synthesis of Single Crystal 2D Cu2FeSnS4 Nanosheets with High-Energy Facets (111) as a Pt-Free Counter Electrode for Dye-Sensitized Solar Cells.

Two-dimensional Cu2FeSnS4 (CFTS) nanosheets with exposed high-energy facets (111) have been synthesized by a facile, scalable, and cost-effective one-pot heating process. The CFTS phase formation is confirmed by both X-ray diffraction and Raman spectroscopy. The formation mechanism of exposed high-energy facet CFTS growth is proposed and its electrochemical and photoelectrochemical properties are investigated in detail to reveal the origin of the anisotropic effect of the high-energy facets. Dye-sensitized solar cells (DSSC) achieve a favorable power conversion efficiency of 5.92% when employing CFTS thin film as a counter electrode, suggesting its potential as a cost-effective substitute for Pt in DSSCs.

Influence of metal salts (Al, Ca, and Mg) on the work function and hole extraction at carbon counter electrodes in perovskite solar cells

Hole transport material-free carbon-based perovskite solar cells (HTM-free C–PSCs) are recognized as a cost-effective and stable alternative to conventional perovskite solar cells. However, the significant energy level misalignment between the perovskite layer and the carbon counter electrode (CE) results in ineffective hole extraction and unfavorable charge recombination, which decreases the power conversion efficiency (PCE). Here, we report the introduction of metal salts (Al, Ca, and Mg) into graphite/carbon black (Gr/CB) CEs to modify the work function and enhance the hole selectivity of the CE. This modification leads to improved energy level alignment, efficient hole extraction, and reduced charge recombination. The PCE of the HTM-free C-PSC based on Al-modified Gr/CB as the CE material reached 9.91%, which is approximately 12% higher than that of devices employing unmodified Gr/CB CEs. This work demonstrates that by directly incorporating metal salts into the Gr/CB CE, the energy level alignment and hole extraction at the perovskite/carbon interface can be improved. This presents a viable method for enhancing the PCE of HTM-free C–PSCs.

TiO2 Crystallization at Room Temperature and Preparation of Transparent Carbon Counter Electrode for Low-Cost Dye-Sensitized Solar Cells

TiO2 Crystallization at Room Temperature and Preparation of Transparent Carbon Counter Electrode for Low-Cost Dye-Sensitized Solar Cells

Wood-derived pore-rich carbon: A green catalyst for counter electrodes of dye-sensitized solar cells

Common Pt-based electrocatalysts have the disadvantages of high cost and easy deactivation. The research focus will be the development of carbon-based counter electrodes (CEs) due to the high conductivity and stability in the electrolytes. This paper prepares a kind of CE with wood-derived pore-rich carbon (WDPRC), which uses poplar as the precursor and activates with KOH at different temperatures (700, 800, and 900 °C). 800-WDPRC (800 represents temperature) had a large specific surface area of 1234.30 m2/g, which shows that it has a rich pore structure, and provides more active sites for the reaction. And the DSSCs’ PCE with 800-WDPRC (5.99%) is higher than the wood-derived carbon (WDC) (carbonize at 800 °C and without activation) (2.32%). As for the CEs’ materials, the WDPRCs’ manufacturing process is simple (only two steps), and the materials used are environment-friendly and low in price. Therefore, this paper provides a new idea for preparing clean and efficient DSSCs’ CEs.

Morphology-dependent catalysis on nanostructures Fe2O3@MWCNT as Pt-free counter electrode for dye-sensitized solar cells

The doped transition metal oxides (TMOs) substitute for the traditional Pt as the counter electrode (CE) catalyst is a unique way to reduce the cost and improve the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Herein, four different morphologies and size of Fe2O3 (nanodiscus (ND), nanocubes (NC), nanorings (NR), nanoball (NB)) assisted by multi-walled carbon nanotube (MWCNT) to prepare Fe2O3@MWCNT composites, and then were further utilized in the encapsulated DSSCs. The obtained different morphologies Fe2O3@MWCNT composites had been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption-desorption. The significant effects of different morphologies of Fe2O3 on the electrochemical activity of Fe2O3@MWCNT composites as CEs were confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization experiments. The DSSCs using Fe2O3@MWCNT composites CEs achieved high PCEs of 6.34 (ND), 6.53(NC), 6.65(NR), and 7.09% (NB) to regenerate traditional I3−/I− shuttles by the photocurrent-photovoltage (J-V) test, respectively, which is due to the synergistic effect between Fe2O3 and MWCNT to improve electrical conductivity and promote a high number of active catalytic sites, implying a remarkable alternative of Pt-free catalyst that can be applied to the encapsulated DSSCs as CEs.

Polyoxovanadate derived VN@C composite catalysts by different synthesis routes as Pt-free counter electrode for dye-sensitized solar cells

Vanadium-based nitrides have been applied as Pt-free counter electrodes (CEs) electro-catalysts for dye-sensitized solar cells (DSSCs) due to inexpensive cost and easy doping and modification. Herein, polyoxovanadate (NH4)2V6O16 assisted by melamine to prepare VN@C composites by five different synthesis routes, including solvothermal, sol–gel, hydrothermal, ball milling, and chemical mixing method. And then, five VN@C composites were assembled as CEs in the encapsulated DSSCs, and yielded power conversion efficiencies of 4.47, 5.04, 5.35, 5.49 and 6.11% for regenerate traditional I3−/I− shuttles by the photocurrent-photovoltage (J-V) test, respectively. The catalytic performances of VN@C composites CEs were assessed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization experiments, and the significant effects of different synthetic routes were confirmed. The results revealed that VN@C composite CEs prepared by chemical mixing method had higher catalytic performance in DSSCs, which is due to the improvement of conductivity and the high concentration of active sites.

A novel of WS2–MoCuO3 supported with graphene quantum dot as counter electrode for dye-sensitized solar cells application

A novel tungsten disulfide-molybdenum copper oxide composite supported with graphene quantum dots (WM@GQDs) has been synthesized as a counter electrode (CE) for dye-sensitized solar cells (DSSCs) using a simple and low-cost ultrasonication method. The unique structure of WM@GQDs exhibits excellent power conversion efficiency due to its high catalytic activity and charge transport properties. In addition, the graphene quantum dots (GQDs) provide more active sites in the zero-dimensional materials for an I/I3− redox reaction which can improve the electrical and optical properties of the composite. The results indicate that the amount of GQDs in the composite affect the effectiveness of solar devices. When 0.9%wt of GQDs was used, the WM@GQDs composite achieved an efficiency of 10.38%, which is higher than that of the expensive platinum CE under the same conditions. The mechanism behind the improved power conversion efficiency (PCE) of the composite sample is also discussed in detail. Therefore, WM@GQDs can be an efficient material to replace platinum in DSSCs as a CE.

Waste to wealth: Oxygen-nitrogen-sulfur codoped lignin-derived carbon microspheres from hazardous black liquors for high-performance DSSCs

Carbon materials are effective substitutes for Pt counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). However, many of these materials, such as carbon nanotubes and graphene, are expensive and require complex preparation process. Herein, waste lignin, recycled from hazardous black liquors, is used to create oxygen-nitrogen-sulfur codoped carbon microspheres for use in DSSC CEs through the facile process of low-temperature preoxidation and high-temperature self-activation. The large number of ester bonds formed by preoxidation increase the degree of cross-linking of the lignin chains, leading to the formation of highly disordered carbon with ample defect sites during pyrolysis. The presence of organic O/N/S components in the waste lignin results in high O/N/S doping of the pyrolysed carbon, which increases the electrolyte ion adsorption and accelerates the electron transfer at the CE/electrolyte interface, as confirmed by density functional theory (DFT) calculations. The presence of inorganic impurities enables the construction of a hierarchical micropore-rich carbon structure through the etching effect during self-activation, which can provide abundant catalytically active sites for the reversible adsorption/desorption of electrolyte ions. Under these synergistic effects, the DSSCs that use this novel carbon CE achieve a quite high power-conversion efficiency of 9.22%. To the best of our knowledge, the value is a new record reported so far for biomass-carbon-based DSSCs.

Controlling the electrocatalytic activities of conducting polymer thin films toward suitability as cost-effective counter electrodes of dye-sensitized solar cells

Role dopant anions and solvents in electropolymerized conducting polymers (CPs) on controlling the morphology of thin films and electrocatalytic activities to judge their suitability as low-cost counter electrodes (CE) of dye-sensitized solar cells ( DSSCs) was systematically investigated. Amongst various CPs such as polyaniline (PANI), polypyrrole (PPy), and PEDOT with sodium dodecyl sulfate (SDS) as a dopant, PEDOT was found to exhibit the best photovoltaic performance with a photoconversion efficiency (PCE) of 6.99 %. This was attributed to the best electrocatalytic activity due to the smallest ΔEp, most minor R1, and nano-morphology-assisted high surface area, as confirmed by CV, EIS, and FE-SEM investigations. Using PEDOT as CP, the nature of dopants such as SDS, TFSI, and ClO4 has also been found to control the electrocatalytic activities and the morphology of the fabricated thin films affecting overall photovoltaic performance DSSCs. Amongst the various CP-based CE fabricated using different dopants and solvents, PEDOT:TFSI thin films prepared in acetonitrile solvent and used as CE exhibited not only the best electrocatalytic activity as CE but also demonstrated the best photovoltaic performance with PCE of 7.0 %, which almost similar to that of DSSC utilizing Pt as CE with PCE of 7.1 %. Therefore, it was concluded that the nature of CP and dopant ions were vital factors in governing the electrocatalytic activities of the thin films to ensure their suitability as CE for optimal functioning and controlling the DSSC performance.

A Review of Transition Metal Sulfides as Counter Electrodes for Dye-Sensitized and Quantum Dot-Sensitized Solar Cells.

Third-generation solar cells, including dye-sensitized solar cells (DSSCs) and quantum dot-sensitized solar cells (QDSSCs), have been associated with low-cost material requirements, simple fabrication processes, and mechanical robustness. Hence, counter electrodes (CEs) are a critical component for the functionality of these solar cells. Although platinum (Pt)-based CEs have been dominant in CE fabrication, they are costly and have limited market availability. Therefore, it is important to find alternative materials to overcome these issues. Transition metal chalcogenides (TMCs) and transition metal dichalcogenides (TMDs) have demonstrated capabilities as a more cost-effective alternative to Pt materials. This advantage has been attributed to their strong electrocatalytic activity, excellent thermal stability, tunability of bandgap energies, and variable crystalline morphologies. In this study, a comprehensive review of the major components and working principles of the DSSC and QDSSC are presented. In developing CEs for DSSCs and QDSSCs, various TMS materials synthesized through several techniques are thoroughly reviewed. The performance efficiencies of DSSCs and QDSSCs resulting from TMS-based CEs are subjected to in-depth comparative analysis with Pt-based CEs. Thus, the power conversion efficiency (PCE), fill factor (FF), short circuit current density (Jsc) and open circuit voltage (Voc) are investigated. Based on this review, the PCEs for DSSCs and QDSSCs are found to range from 5.37 to 9.80% (I-/I3- redox couple electrolyte) and 1.62 to 6.70% (S-2/Sx- electrolyte). This review seeks to navigate the future direction of TMS-based CEs towards the performance efficiency improvement of DSSCs and QDSSCs in the most cost-effective and environmentally friendly manner.

Selenization treatment on Ag8SnSxSe6-x counter electrode of dye-sensitized solar cells in improving its electron transfer and electrocatalytic activity

In this paper, Ag8SnS6 powder was synthesized by the one-pot method, then prepared into Ag8SnS6 and Selenization treated Ag8SnSxSe6-x thin films. The effects brought by the amounts of added Se powder during the annealing process on the product phases, structures, and morphologies are characterized, and the electrochemical property and the cell efficiency as assembled into the counter electrode (CEs) for dye-sensitized solar cells (DSSCs) were investigated. It showed Se into the Ag8SnS6 lattice occupied the site of S to transform into Ag8SnSxSe6-x. And the thin film also became unflatten since the particles became larger after Se doping. The cell efficiency of Ag8SnSxSe6-x CEs reached 4.26%, which was increased by 28.31% compared to that of Ag8SnS6 CEs. Ag8SnSxSe6-x CEs performed lower charge transfer resistance (Rct) and (△EPP), and an increased△E value between the conduction band level of CEs and the redox potential of electrolyte. After 10 cycles, the almost unchanged cathode/anode current density implied the Ag8SnSxSe6-x CEs received good structure stability. Selenization treatment was able to facilitate electron transport and enhance the electrocatalytic activity, and as expected to be a promising method in improving the performance of the DSSCs.

A highly porous MgO entrenched MWCNT composite as a low-cost Pt-free counter electrode for dye-sensitized solar cells and visible light photocatalytic performance towards Congo-red

A highly porous MgO entrenched MWCNT composite as a low-cost Pt-free counter electrode for dye-sensitized solar cells and visible light photocatalytic performance towards Congo-red

A quaternary nanocomposite as an efficient counter electrode for Pt-free Dye-sensitized solar cells (DSSC)

Solar Cells are one of the most promising energy conversion sources available. But most solar cells use conventional Pt as a counter electrode (CE) which is very costly, scarce and corrosive in liquid medium. So, an alternative novel quaternary nanocomposite of rGO Reduced graphene oxide (rGO)/ Manganese dioxide (MnO2)/ Nickel oxide (NiO)/Copper oxide (CuO) (RMNCu) was employed under varied photoanodes like hydrothermally synthesized Titanium dioxide (TiO2), Zinc oxide (ZnO) and TiO2/ZnO with N-719 as dye matrix over Fluorine-doped Tin Oxide (FTO) substrate. The fabricated Dye-Sensitised Solar Cell (DSSCs) were examined under functional, optical and photovoltaic studies. It was found that the prepared DSSC with RMNCu as CE had a Power Conversion Efficiencies (PCE) of 93.31% of Pt-CE in the same ambience. The uplifted conversion efficiency promotes RMNCu as a promising candidate for counter electrodes for DSSC.

Facile fabrication of ZnCo2S4@MWCNT as Pt-free counter electrode for high performance dye-sensitized solar cells

Substitution of platinum as a counter electrode material in dye-sensitized solar cells (DSSCs) is critical because Pt is rare and expensive. In addition, Pt-based counter electrodes have problems with the long-term stability of DSSCs. Among Pt-free electrocatalysts, composite materials are of great interest because they can be advantageous due to the combined performance of their components. Here, we present a ternary ZnCo2S4 composite grown on multi-walled carbon nanotubes as a Pt-free counter electrode for the reduction of triiodide in DSSCs. The composite ZnCo2S4@MWCNT was synthesized in a simple two-step process: (i) spray coating of a MWCNT dispersion on a FTO glass substrate, followed by (ii) solvothermal growth of the ternary sulfide ZnCo2S4 on a MWCNT layer. Cyclic voltammetry analyzes showed superior electrocatalytic activity of the composite in the reduction of triiodide compared to Pt. Electrochemical impedance spectroscopy measurements of symmetric dummy cells showed lower charge transfer resistance of ZnCo2S4@MWCNT (RCT = 5.54 Ω × cm2) than the traditional Pt electrocatalyst (7.07 Ω × cm2) in catalyzing the triiodide-to-iodide conversion reaction. The photovoltaic measurements of dye-sensitized solar cells showed an improved conversion efficiency of ZnCo2S4@MWCNT (8.55%) with excellent stability compared to Pt (8.19%).

Combustion-Assisted Polyol Reduction Method to Prepare Highly Transparent and Efficient Pt Counter Electrodes for Bifacial Dye-Sensitized Solar Cells.

A combustion-assisted polyol reduction (CPR) method has been developed to deposit electrocatalytically efficient and transparent Pt counter electrodes (CEs) for bifacial dye-sensitized solar cells (DSSCs). Compared with conventional thermal decomposition of Pt precursors, CPR allows for a decrease in reduction temperature to 150 °C. The low-temperature processing is attributed to adding an organic fuel, acetylacetone (Hacac), which provides extra heat to lower reduction energy. In addition, the stable Pt complexes can simultaneously be formed in ethylene glycol (EG) and Hacac system, which leads to Pt nanoparticle size regulation. A ratio of Hacac to EG is optimized to achieve excellent electrocatalytic activity and high visible light transmittance for CEs. The bifacial DSSCs fabricated with CPR-Pt CEs (EG : Hacac=1 : 16) reach efficiencies of 6.71±0.16% and 6.41±0.15% in front and back irradiations, respectively.

Fe2O3–NiO doped carbon counter electrode for high-performance and long-term stable photovoltaic perovskite solar cells

Perovskite solar cells (PSCs) based on carbon have been viable contenders in the field of photovoltaic due to their low cost, outstanding stability in high-humidity atmospheric air, and high electrical conductivity. Also, using inexpensive counter electrodes with PSCs devoid of organic hole transport materials (OHTMs) might be one way to get around the cost problem. Herein, at first, two different metal oxide nanoparticles (Fe2O3-NPs and NiO-NPs) were synthesized by a novel and cost-effective process. Then these nanoparticles were doped in carbon paste as a hole-transporting material (HTM) to improve charge extraction, interface contact, and energy level alignment, as well as reduction of energy loss, charge recombination, and perovskite surface degradation. The photovoltaic properties of these devices were investigated. All cells showed better efficiency than the control cell, but Fe2O3–NiO@C had better performance with high hole conductivity, matched energy level, and staircase band alignment of perovskite/Fe2O3–NiO@C. Fe2O3 has a higher valence band (VB) than NiO, which facilitates the holes transfer from perovskite and NiO to counter electrode and accelerates the separation of photogenerated electron–holes. The optimal device, FTO/c-TiO2/m-TiO2/perovskite/Fe2O3–NiO@C, achieves a power conversion efficiency (PCE) of 13.27% without encapsulation, compared to the control device (9.49%), and has outstanding long-term stability, retaining almost 82% of its initial efficiency over 720 h. The control device, FTO/c-TiO2/m-TiO2/perovskite/C, kept 66% of the original PCE after 720 h. Therefore, the PSCs based on Fe2O3–NiO doped carbon demonstrated substantial PCE and have good stability in ambient settings, thus making them one of the least expensive PSCs to commercialize.

Pyrolysis synthesis of CuWO4@C composite catalysts as Pt-free counter electrode for dye-sensitized solar cells

Transition metal compound catalysts have potential applications in Pt-free counter electrode (CE), which are one of the important strategies for reducing costs and improving power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Herein, CuWO4@C composite catalysts were synthesized by pyrolyzing Cu-based polyoxotungstate (H3PW12O40) precursor in presence of polyaniline. The effect of pyrolysis temperature (600, 700, 800, 900, 1000 and 1100 ℃) on the compositions, morphologies and structures of CuWO4@C composite was investigated by Thermogravimetry-Derivative thermogravimetry-Differential scanning calorimetry (TG-DTG-DSC) simultaneous, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and N2 adsorption-desorption analysis. The photovoltaic properties of different CuWO4@C composites CEs were determined by photocurrent-photovoltage (J-V) measurement. The results reveal that the pyrolysis at 800 ℃ was optimum to get the best CuWO4@C composite CE, which yielded the highest PCE of 7.11% for the regeneration of I3−/I− couple in the DSSCs. The structure-activity relationship of the CuWO4@C composite catalysts was discussed.

Facile synthesis of ZnCo2O4@NiMoO4 with porous coated structures on carbon paper as stable and efficient Pt-free counter electrode materials for advanced dye-sensitized solar cells

A porous coating structure transition metal oxide ZnCo2O4@NiMoO4 composite was successfully synthesized on the surface of carbon paper (CP) by a simple two-step hydrothermal method as a Pt-free material for titanium mesh substrate counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). According to BET test results, the material has a high specific surface area, which can provide abundant active sites for the redox reaction of electrolytes to enhance the utilization rate of sunlight by DSSCs, and the composite materials show remarkable electrocatalytic performance in reducing iodine electrolytes and improving the photoelectric conversion efficiency (PCE) of DSSCs. Therefore, the DSSCs equipped with ZnCo2O4@NiMoO4/CP material CEs achieve a PCE of 9.30 % (with Jsc of 20.51 mA·cm−2, Voc of 0.763 V, and FF is 0.60), which is much higher than that of Pt CEs (7.36 %) under the same light conditions. This is due to the excellent catalytic ability and good electrical conductivity of the composite material. On the other hand, because the titanium mesh can increase the contact area between the electrode material and the substrate compared with the FTO substrate, and the titanium mesh has good electrical conductivity, it can enhance the diffusion ability of I-/I3- to accelerate electron transmission.

Design of blueberry anthocyanin/TiO2 composite layer-based photoanode and N-doped porous blueberry-derived carbon-loaded Ni nanoparticle-based counter electrode for dye-sensitized solar cells.

P25/PBP (TiO2, anthocyanins) prepared by combining PBP (blueberry peels) with P25, and N-doped porous carbon-supported Ni nanoparticles (Ni@NPC-X) prepared using blueberry-derived carbon were used for the application as photoanode and the counter electrode, respectively, in dye-sensitized solar cells (DSSCs) to create a new perspective for blueberry-based photo-powered energy systems. PBP was introduced into the P25 photoanode and carbonized to form a C-like structure after annealing that improved its adsorption capacity for N719 dye, contributing a 17.3% higher power conversion efficiency (PCE) of P25/PBP-Pt (5.82%) than that of P25-Pt (4.96%). The structure of the porous carbon changes from a flat surface to a petal-like structure due to the N doping by melamine, and the specific surface area increases. N-doped three-dimensional porous carbon supported the loading and reduced the agglomeration of Ni nanoparticles, reducing the charge transfer resistance, and providing a fast electron transfer path. The doping of Ni and N on the porous carbon worked synergistically to enhance the electrocatalytic activity of the Ni@NPC-X electrode. The PCE of the DSSCs assembled by Ni@NPC-1.5 and P25/PBP was 4.86%. Also, the Ni@NPC-1.5 electrode exhibited 116.12 F g-1 and a capacitance retention rate of 98.2% (10 000 cycles), further confirming good electrocatalysis and cycle stability.

Facile synthesis of NiS nanowires via ion exchange reaction as an efficient counter electrode for dye-sensitized solar cells

This paper proposes a strategy for the facile preparation of NiS nanowires via ion exchange reaction. This special synthesis process enables NiS nanowires to form a tightly connected network of transported electrons and a hierarchical porous structure with a large specific surface area.