Electrodes For Solar Cells Research Articles

Oxide–Metal–Oxide Based Transparent Electrodes and Their Potential Application in Semitransparent Perovskite Solar Cells‐Optical Modeling Studies

Oxide–metal–oxide (OMO)‐based stacks are highly attractive by virtue of their favorable properties for being used as a top transparent electrode (TE) in semitransparent solar cells. Herein, getting the best trade‐off between performance and transparency is focused on by optimizing the OMO electrode and the device layers with the help of optical simulation. NiO/Ag/SnO2 as the OMO electrode integrated into a device having SnO2, Spiro‐OMeTAD, and MAPbI3 as the electron transport layer, hole transport layer, and photoactive layer, respectively, in n–i–p geometry is investigated. It is shown that an optimized OMO electrode in terms of average visible transparency (AVT) does not translate to the best device performance. It is found that for the overcoat to undercoat oxide layer ratio of 1.17, a maximum short‐circuit current density (JSC) of 4.34 mA cm−2 is achieved while a maximum AVT of 21.55% is obtained for a ratio of 0.78. On further optimization of the MAPbI3 thickness, for an oxide ratio of 1, a modeled device with 4.58 mA cm−2 with AVT of 31.55% is demonstrated. In addition, it is also found that by integrating an optical spacer layer after the OMO electrode, the JSC of the device shows a jump of >115% to 9.86 mA cm−2.

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.

Spiro-OMeTAD versus PTAA for single-walled carbon nanotubes electrode in perovskite solar cells

Poly(triarylamine) (PTAA)-wrapped single-walled carbon nanotubes (SWCNTs) functioned in a dual role as an efficient hole-transporting layer and electrode in perovskite solar cells (PSCs). Thanks to the well-matched energy level, increased hole-transporting mobility, and hydrophobicity rendered by dopant-free PTAA, this dual-role SWCNTs electrode applied-PSCs using dopant-free PTAA achieved a better efficiency and stability than reference standards using LiTFSI-doped Spiro-OMeTAD. This dopant-free PTAA-applied SWCNTs electrode is expected to not only give a solution for efficiently using the SWCNTs electrode in PSCs, but also unveil the mechanism of the interaction between the hole-transporting layer and SWCNTs.

Joining mechanism of parallel gap resistance welded dissimilar connection between Ag interconnector and GaAs solar cell: A transmission electron microscopy study

Quality of connections between solar cells directly influences the life of a spacecraft in complex space environment, which thus makes clarification of joining mechanism between interconnector and solar cell electrode by certain method a necessity for further quality improvement of solar array. In the present research, the connection between Ag interconnector and GaAs solar cell is performed using parallel gap resistance welding (PGRW) under a set of appropriate parameters to achieve optimal bonding that possesses adequate strength without degrading photoelectric property of cell. To characterize the microstructure and element distribution at interface in detail, advanced transmission electron microscopy (TEM) was conducted. According to the obtained results, the PGRW interface between Ag interconnector and Au plated Ag electrode of GaAs solar cell shows a solid-solution phenomenon via element diffusion. Also, under the compressive force and thermal input during PGRW, twins are found originating along the grain boundary from Ag interconnector into Ag layer of GaAs solar cell crossing the Au surface. The characterization findings have confirmed the capability of achieving solid-state diffusion connection by PGRW.

Synthesis of Graphene Oxide (GO) by Modified Hummer’s Method with Improved Oxidation through Ozone Treatment

Graphene Oxide (GO) is one of the common members of the graphene family owing to its unprecedented and unique properties. These properties attract researchers to use GO in several potential applications such as a transparent electrode in light-emitting diodes (LED), biosensors and solar cells, etc. In this work, GO was produced through the oxidation of graphite by potassium permanganate using modified Hummer’s method and this was followed by ozone treatment. The crystallographic structure, chemical properties, surface morphologies, and optical properties of before and after treatment of GO were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and UV- visible spectroscopy. The FTIR observation confirmed the formation of GO from graphite flakes. XRD results showed peak at11.6˚ with a different interlayer spacing of 0.7nm and 0.8nm for GO and ozone-treated graphene oxide (O- GO) respectively. While for both GO and O- GO all the peaks were at the same position. Further, SEM micrographs of GO exhibited the multilayered graphene oxide with variable thickness. While the rough surface of O- GO suggests the reduction of GO particle size due to ozonation. Ultraviolet-visible spectra of GO at 223.2 nm was noted which is attributed to atomic C- C bonds but O- GO exhibited the peak shift at 232.7 nm thereby suggesting a higher surface area.

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.

Fuel-assisted polyol reduction for highly transparent and efficient Pt counter electrodes in bifacial dye-sensitized solar cells

Organic fuels allowed for manufacturing highly transparent and efficient Pt counter electrodes.

Advances in the research of carbon electrodes for perovskite solar cells.

Perovskite solar cells (PSCs) were first proposed in 2009. They have the advantages of low cost, a simple manufacturing process and excellent photoelectric performance. PSC electrodes are mainly made from precious metals such as gold and silver. Still, the cost of precious metals is high and they react with the other components of the PSCs, resulting in the poor stability of the photovoltaic device. Using carbon as an electrode material can both reduce the cost and significantly improve the stability of the photovoltaic device. However, the poor interface contact between the carbon electrode and perovskite and carbon electrode resistance results in poor photovoltaic device photoelectric performance. Finding a way to successfully utilize carbon as an alternative electrode material is a key step toward moving PSCs from the laboratory to industrialization. This paper reviews the application of carbon black, graphite, graphene, carbon nanotubes (CNTs) and composite carbon electrode in PSCs, focusing on progress in the research of doping, structure, interface modification and the production process.

Unveiling and overcoming the interfacial degradation between CuSCN and metal electrodes in perovskite solar cells

The interfacial degradation at the CuSCN/Au interface due to Au–Cu alloying can be improved by replacing Au with carbon electrodes, delivering high device stability under light illumination.

Iridium-palladium binary alloy as a counter electrode in dye-sensitized solar cells.

This study is concerned with the iridium-palladium (Ir-Pd) binary alloy as a counter electrode (CE) for DSSC. The CE was prepared using the liquid phase deposition (LPD) technique. The influence of the concentration of hydrogen hexachloroiridate(IV) hydrate (H2Cl6Ir·H2O) on the properties and the performance of the device was investigated. The source of iridium was H2Cl6Ir·H2O. XRD analysis confirmed that the dominant phase of Ir-Pd existed in the sample. The grain size of Ir-Pd increased with the increase in the concentration of H2Cl6Ir·H2O until an optimum concentration of 0.7 mM was reached. The % wt of Ir was found to increase with the concentration of H2Cl6Ir·H2O. The device utilizing Ir-Pd CE with 0.7 mM H2Cl6Ir·H2O demonstrated the highest power conversion efficiency (PCE) of 5.84%, beating that of the device with Pt CE having a PCE of 5.04%. This is because the device possesses the lowest charge transfer resistance (Rct), highest recombination resistance (Rcr), and longest carrier lifetime (τ), and the device possesses the highest reduction current (Jpc) and incident-photon conversion efficiency (IPCE). The PCE was significantly affected by Ir content in the binary alloy of Ir-Pd. According to the PCE result, Ir-Pd CE was found as a suitable substitution for Pt as CE for the device.

Fabrication of cellulose paper-based counter electrodes for flexible dye-sensitized solar cells.

Here, we introduce the synthesis and deposition of organic/inorganic composite ink on cellulose paper using a rapid ultrasonic spray deposition approach that can be incorporated as a counter electrode (CE) in flexible dye-sensitized solar cells (FDSSCs). The composite ink comprised a copper indium sulfide (CuInS2) nanostructure ink and dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) in water. Fabricated counter electrodes are biodegradable, environment-friendly, flexible, and economical and meet the requirements for sustainable green energy. To evaluate the catalytic activities and power conversion efficiencies of DSSCs, the produced CuInS2/PEDOT:PSS composite ink-based CEs were compared with PEDOT:PSS counter electrodes. Cyclic voltammetry studies found that CuInS2/PEDOT:PSS had a greater cathodic charge transfer current density (Jc) (-1.23 mA cm-2). Moreover, it was found that the potential separation values are small, which indicate a stronger catalytic activity than PEDOT:PSS counter electrodes. The observed exchange current density (J0) was 3.98 mA cm-2, while the limiting current density (Jlim) increased to 45.7 mA cm-2, indicating a fast redox diffusion rate of the CuInS2/PEDOT:PSS CE. The photovoltaic performances of CuInS2/PEDOT:PSS and PEDOT: PSS-based DSSC's were measured and determined to be 5.66% and 4.41%, respectively, while the performance of CuInS2/PEDOT:PSS FDSSC composed of cellulose paper was 1.06%.

Transparent PEDOT counter electrodes for bifacial dye-sensitized solar cells using a cobalt complex mediator.

Poly(3,4-ethylenedioxythiophene) (PEDOT) aggregate-deposited counter electrodes (CEs) were applied to bifacial dye-sensitized solar cells with a cobalt complex electrolyte. The high transparency and excellent electrochemical activity of PEDOT CEs result in an impressive cell bifaciality of 0.92 under standard test conditions (AM 1.5G, 100 mW cm-2), and maximum power production of 11.3% under realistic conditions with an effective albedo of 50%.

Photoelectric properties of the layered raspberry sandwich amorphous ZnCo2S4@MnCo2S4/CP composite counter electrode in semiconductor-sensitized solar cells.

Multistage amorphous materials have promising applications in the catalytic performance of dye-sensitized solar cells (DSSCs). Herein, an amorphous sheet-raspberry sandwich-like ZnCo2S4@MnCo2S4/CP composite material was rationally designed and developed as a counter electrode (CE) for DSSCs by applying a three-step hydrothermal method. The first development of the amorphous composites as CEs resulted in lower charge transfer resistance at the CE/electrolyte interface and improved the fill factor and short-circuit current density. The excellent catalytic performance is mainly attributed to the large number of unsaturated coordination sites generated by the undirected structure of the lamellar-raspberry intercalated amorphous material, the smooth ion transport interface with a self-built corrosion-resistant layer, coupled with the dual catalytic performance of the Zn, Co, and Mn composites, and the good electrical conductivity of the C substrate. When ZnCo2S4@MnCo2S4/CP was used as the CE on a Ti substrate, the photoelectric conversion efficiency was as high as 11.68% (Voc = 0.821, Jsc = 20.14 mA cm-2, and FF = 0.71) under 100 mW cm-2 light illumination. This paper provides a design idea for amorphous materials in terms of catalytic performance and a method for developing alternatives to Pt electrodes.

Titanium dioxide Ag NP enhanced solid solar cell electrodes for favourable efficiency

Population growth leads to a heightened demand for working potential to support modern commercial and residential evolutions. Available conventional energy sources, however, cause environmental pollution and severe health problems like global warming. The current energy sources also face challenges due to factors like global warming that make hydro-generated energy production even more difficult due to droughts. Therefore, alternative energy options need to be explored. The study in question aimed to find a cost-effective and environmentally friendly energy source by fabricating a solar cell that uses titanium dioxide and potassium iodate (mixed in carbon) layers in a solidified structure. TiO2 was chosen due to its photo-generating properties and synthetic steadiness over a spread acidity/basicity neutrality. The iodine/iodide complex was used to replenish the photo-excited electrons while graphite facilitated their migration. The researchers varied the ingredients capacities for the separate electrodes keeping the rest unvaried for improved (I-V) terminal parameters. Deduction from the research established that the (0.4:0.3:0.17:0.01) TiO2/CX:I2:KI proportions resulted in the optimum charge range generation. The inclusion of potassium iodate (KI) improved iodine solvability and facilitated even dispersal in graphite, which was maintained at 0.01 g in all cells. The absorber and receptive layer thicknesses of 2.00 mm and 1.00 mm respectively generated the best 0.979 V open-circuit voltage (Voc) and 12.037 μA short-circuit current (Isc) results. Favorable (10.46%) efficiency (η) and (0.64) fill factor (FF) were derived. Conducting transparent glass was suggested for improving the linkage to the external circuit and models of reducing air pockets in the solid TiO2 photovoltaic devices could further enhance their performance.

Spin-coating of Graphene Oxide as Counter Electrode for Dye-sensitized Solar Cells in Various Dispersing Solvents

Platinum (Pt) is the most commonly used counter electrode material for DSSCs. However, as Pt is a noble metal and expensive, researchers have tried to replace the Pt counter electrode with a variety of materials. In this study, graphene oxide (GO) powders were added to solvents of different polarities as precursor solutions for the counter electrode. The solvents were deionized water, dimethylformamide, isopropanol, and chlorobenzene in descending order of polarity. The prepared GO precursor solutions were coated on the Florine doped Tin Oxide (FTO) glass substrate via spin coating, then coated substrate subjected to thermal reduction reaction to obtain reduced graphene oxide, which was used as the counter electrode of the DSSC. The photoelectric conversion efficiency (PCE) of DSSC using deionized water as the dispersing solvent was 2.70%, which was five times higher than that of DSSC using chlorobenzene.

Core/shell AgNWs@SnOx electrodes for high performance flexible indoor organic solar cells with >25% efficiency

In this work, an inorganic semiconductor SnOx has grown on the surface of silver nanowires (AgNWs) to form core/shell electrodes, which was successfully applied into flexible indoor organic solar cells (OSCs). Based on the redox reaction between Sn2+ and Ag+, the pristine AgNWs thin films were treated by SnCl2 in an aqueous solution, so that SnOx was generated and meanwhile the defect on the surface of AgNWs (ex. Ag+ and polyvinylpyrrolidone) was removed. SnOx can not only improve the stability, but also more importantly, tune the work function of AgNWs due to its n-type semiconducting nature. Therefore, photogenerated charges were efficiently injected and collected at the electrode. With this AgNWs@SnOx electrode, flexible indoor OSCs provided a high efficiency of 25.51% under 1000 lux illumination, while the unmodified AgNWs electrode only showed an efficiency of 18.84%.

Characterization of PAN-TiO2 Nanofiber Mats and their Application as Front Electrodes for Dye-sensitized Solar Cells

In the context of the energy transition to renewables, the spotlight is on large systems connected to the power grid, but this also offers room for smaller, more specialized applications. Photovoltaics, in particular, offer the possibility of the self-sufficient supply of smaller electrical appliances on smaller scales. The idea of making previously unused surfaces usable is by no means new, and textiles such as backpacks, tent tarpaulins and other covers are particularly suitable for this purpose. In order to create a non-toxic and easily recyclable product, dye-sensitized solar cells (DSSC), which can be manufactured through electrospinning with a textile feel, are an attractive option here. Therefore, this paper investigates a needle electrospun nanofiber mat, whose spin solution contains polyacrylonitrile (PAN) dissolved in dimethyl sulfoxide (DMSO) as well es TiO2 nanoparticles. In addition to characterization, the nanofiber mat was dyed in a solution containing anthocyanins to later serve as a front electrode for a dye-sensitized solar cell. Although of lower efficiency, the DSSC provides stable results over two months of measurement.

Synthesis of lignite-based Ni/C composite with low-medium temperature pyrolysis method as an efficient Pt-free counter electrode for dye-sensitized solar cells

In order to obtain inexpensive Pt-free counter electrode materials for dye-sensitized solar cells and expand the application fields of low-rank coal, lignite-based Ni/C composite was prepared by low-medium temperature pyrolysis method using Huolinhe lignite as raw materials. The structure and chemical components of as-synthesized lignite-based Ni/C composite was characterized by XRD, FT-IR, TG, Raman, SEM, TEM, and XPS, and the electrocatalytic activity of lignite-based Ni/C composite counter electrode was investigated by cyclic voltammetric curve, electrochemical impedance spectrum, and Tafel polarization curve. It is found that the electrocatalytic activity of the lignite was improved after low-medium temperature pyrolysis and composited with Ni species to form lignite-based Ni/C composite, which helps to catalyze the reduction of electrolyte and thus improve the photoelectric conversion efficiency of the solar cells. The photoelectric conversion efficiency (η) of the dye-sensitized solar cells based on the lignite-based Ni/C composite counter electrode was 3.42% (Jsc = 11.49 mA cm−2, Voc = 0.75 V, FF = 0.40) significantly higher than that of the lignite counter electrode (η = 0.20%, Jsc = 3.16 mA cm−2, Voc = 0.72 V, FF = 0.09). This indicates that low-medium temperature pyrolysis and composition with Ni are an effective method to improve the photovoltaic performance of lignite-based counter electrode materials.Graphical abstractThe lignite-based Ni/C composite was synthesized and applied in counter electrode for DSSCs.