Electrodes For Perovskite Solar Cells Research Articles

Mass scale synthesis of graphene nanosheets using waste cardboard for application in perovskite solar cells and supercapacitors

Advanced graphene-based materials have been proficiently incorporated into next-generation solar cells and supercapacitors because of their high electrical conductivity, large surface area, excellent charge-transport ability, and exceptional optical properties. Herein, we report the synthesis of graphene nanosheets (GNs) from waste cardboard via pyrolysis, with ethyl alcohol as the growth initiator. Additionally, we demonstrated the use of GNs in energy conversion and storage applications. Using the GN electrode in perovskite solar cells resulted in an excellent power conversion efficiency of ∼10.41 % for an active area of 1 cm2, indicating an enhancement of approximately 27 % compared to conventional electrodes. Furthermore, the GNs were used as active electrode materials in supercapacitors with excellent electrochemical performance and a high gravimetric specific capacitance of 167.5 F/g at a scan rate of 2 mV/s. The developed GNs can be efficiently used for energy storage, conversion, and electrochemical sensing applications.

Transferred Metal Electrodes for Perovskite Solar Cells with Doping‐Tuned Hole‐Transporting Layer

As an alternative technology to the standard evaporated metal top electrode in perovskite solar cells, the transfer method top electrode is featured with low cost, simple process, and ease of scalability. However, as the transfer method preparation of the less expensive metal electrodes (Ag and Cu) is explored, the mismatch between the hole‐transport layer and the top electrode results in anomalous photovoltaic properties. In this study, the work function of the hole‐transporting material is adjusted by changing the dopant content to achieve a good energy‐level match with either Ag or Cu electrode material. The power conversion efficiencies of perovskite devices based on transferred Ag and Cu electrodes can reach 18.41% and 17.25%, respectively, which are comparable to the performance of the evaporated top electrode devices.

Polymer-acid-metal quasi-ohmic contact for stable perovskite solar cells beyond a 20,000-hour extrapolated lifetime

The development of a robust quasi-ohmic contact with minimal resistance, good stability and cost-effectiveness is crucial for perovskite solar cells. We introduce a generic approach featuring a Lewis-acid layer sandwiched between dopant-free semicrystalline polymer and metal electrode in perovskite solar cells, resulting in an ideal quasi-ohmic contact even at elevated temperature up to 85 °C. The solubility of Lewis acid in alcohol facilitates nondestructive solution processing on top of polymer, which boosts hole injection from polymer into metal by two orders of magnitude. By integrating the polymer-acid-metal structure into solar cells, devices exhibit remarkable resilience, retaining 96% ± 3%, 96% ± 2% and 75% ± 7% of their initial efficiencies after continuous operation in nitrogen at 35 °C for 2212 h, 55 °C for 1650 h and 85 °C for 937 h, respectively. Leveraging the Arrhenius relation, we project an impressive T80 lifetime of 26,126 h at 30 °C.

Application of Carbon Materials in Conductive Electrodes for Perovskite Solar Cells

Over the past decade, perovskite solar cells (PSCs) have achieved significant achievements. But the golden triangle problem of commercial development, which encompasses high efficiency, high stability, and low cost, remains unresolved. Carbon materials exhibit a diverse range of morphological structures and possess numerous advantages. They are extensively used in PSCs to overcome the challenges encountered during PSCs commercialization. The PSCs utilizing graphene as the top electrodes not only deliver an impressive efficiency of 22.8%, but also show exceptional long‐term stability. The PSCs using carbon nanotubes as transparent conductive electrodes obtain an efficiency of 19%, exhibiting significant potential for scalable applications. Herein, the advantages of carbon materials as conductive electrodes are overviewed. The compatibility of carbon materials as conductive electrodes in PSCs, along with the associated challenges, regulatory strategies, and device performance are systematically discussed in terms of their intrinsic characteristics. The application of carbon materials derived from petroleum by‐products and biomass in the top electrodes of PSCs are summarized in detail. Finally, the underlying reasons why PSCs using carbon electrode show a comparatively lower efficiency when compared to conventional devices is analyzed in‐depth. The potential research directions are proposed to promote the development of carbon conductive electrodes in PSCs.

Carbon Electrodes for Perovskite Photovoltaics: Interfacial Properties, Meta‐analysis, and Prospects

Carbon electrodes have gained significant attention as a cost‐effective, sustainable, stable, and scalable replacement for metal electrodes in perovskite solar cells (PSCs). However, traditional carbon‐electrode‐based PSCs (C‐PSCs) lack a hole‐selective layer (HSL) due to their incompatibility with the most effective organic HSLs employed in the PSC literature. In turn, the absence of an HSL has been identified as one of the main factors hindering the performance of C‐PSCs. Consequently, numerous studies have recognized the pivotal significance of the region between the perovskite absorber and the carbon electrode in C‐PSCs, proposing various interfacial engineering strategies to improve the performance of these solar cells. Given the rapid evolution of this field, an up‐to‐date and comprehensive review of C‐PSCs is in order. Key areas of focus of this review include the shift from high‐temperature to low‐temperature carbon electrodes, strategies to improve energetic alignment at the interface, novel approaches such as hole‐selective bilayers, and alternative carbon deposition methods to reduce solvent damage. Additionally, this review presents a comprehensive meta‐analysis—the first of its kind in the C‐PSC literature—to assess how various interfacial modifications impact critical C‐PSC performance metrics, offering valuable insights for future advancements in the field.

NiOx/PANI nanocomposite doped carbon paste as electrode for long-term stable and highly efficient perovskite solar cells.

Carbon-based perovskite solar cells (PSCs) have emerged as a hopeful alternative in the realm of photovoltaics. They are considered promising due to their affordability, remarkable durability in humid environments, and impressive electrical conductivity. One approach to address the cost issue is to use affordable counter electrodes in PSCs that do not require organic hole transport materials (HTMs). This study utilized an innovative and economical method to create NiOx/PANI nanocomposites. Later, these nanoparticles were integrated into a carbon paste to act as an HTM. This incorporation is intended to optimize charge extraction, improve interfacial contact, align energy levels, reduce energy loss, minimize charge recombination, and protect the perovskite (FAPbI3) surface from degradation. The optoelectronic properties of these devices were investigated, and all cells showed improved efficiency compared to control cells. The NiOx/PANI doped carbon (NiOx/PANI+CE) exhibited excellent performance due to strong hole conductivity, well-aligned energy levels, and the formation of stepwise band alignment at the perovskite interface.

Liquid Metal‐Based Perovskite Solar Cells: In Situ Formed Gallium Oxide Interlayer Improves Stability and Efficiency

AbstractIn this study, eutectic gallium–indium alloy (EGaIn) liquid metal is used as the rear electrode for perovskite solar cells (PSCs), where the interfacial properties of the device, particularly the beneficial roles of the surface oxide of the liquid metal, are explored. The findings demonstrate that the native oxide of the EGaIn electrode significantly affects the stability of photovoltaic performance and impedance characteristics including series and shunt resistances. Based on the results, the following hypothesis is formulated: the oxide interlayer serves two crucial functions of a barrier against metal diffusion and a tunnel for enhancing charge extraction and transfer. The results of elemental mapping and trap density calculation support the former function of the hypothesis that the oxide film can effectively prevent metal penetration into the perovskite layer. Furthermore, measurements involving capacitance−voltage and time‐resolved photoluminescence confirm that the oxide film on the liquid metal eliminates the interfacial Schottky barrier, promoting efficient charge extraction and transfer processes. Finally, the investigation is extended to develop flexible PSCs using the EGaIn electrode, which consistently exhibits stable performance during repeated bending cycles. Notably, the EGaIn rear electrode can be readily removed and collected through a straightforward acid treatment, offering a promising avenue for efficient cell recycling.

Fabrication of a Water-Stripped Free-Standing Silver Nanowire Network as the Top Electrode for Perovskite Solar Cells

Fabrication of a Water-Stripped Free-Standing Silver Nanowire Network as the Top Electrode for Perovskite Solar Cells

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.

Quantifying and Reducing Ion Migration in Metal Halide Perovskites through Control of Mobile Ions.

The presence of intrinsic ion migration in metal halide perovskites (MHPs) is one of the main reasons that perovskite solar cells (PSCs) are not stable under operation. In this work, we quantify the ion migration of PSCs and MHP thin films in terms of mobile ion concentration (No) and ionic mobility (µ) and demonstrate that No has a larger impact on device stability. We study the effect of small alkali metal A-site cation additives (e.g., Na+, K+, and Rb+) on ion migration. We show that the influence of moisture and cation additive on No is less significant than the choice of top electrode in PSCs. We also show that No in PSCs remains constant with an increase in temperature but μ increases with temperature because the activation energy is lower than that of ion formation. This work gives design principles regarding the importance of passivation and the effects of operational conditions on ion migration.

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.

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.

Sprayed and mechanical-modified graphite layer as transferred electrode for high-efficiency perovskite solar cells

As an alternative of evaporated metal top electrode in perovskite solar cells, the transferred top electrode technique has the outstanding advantage of simple process. And in the case of carbon based transferred top electrode, the efficiency of corresponding perovskite devices can be higher than 20%. During the solid-to-solid electrode transferring process, it is essential to achieve effective contact and to avoid damage of bottom functional layers for an improved device performance. In this work, a sprayed graphite layer on conductive substrate is employed as transferred top electrode for perovskite solar cells. A simple mechanical polishing treatment is further adopted to modify the surface status of graphite layer. Compared with as sprayed graphite electrode, polished electrode shows better electrical property and optimized interface contact with hole-transporting layer. Thus, the average efficiency of perovskite device with mechanical modified electrode can significantly increase from 16.3% to 19.2%.

Synthesis and application of silver and copper nanowires in high transparent solar cells

Electrodes in new function-flexible optoelectronic devices, need to meet the requirements of foldability and high transmittance. In last decades, thousands of research about copper and silver nanowires promoted the prosperity of photovoltaic industry. In this paper, we focus on the recent progresses of silver and copper nanowires for high transparent solar cell application, including preparation and optimization techniques. In addition, the primary obstacles of nanowire transparent electrodes in perovskite solar cells, organic solar cells and dye sensitized solar cells were discussed. Finally, the application prospects of nanowire-based high transparent solar cells were outlined.

Investigation of PCBM/ZnO and C60/BCP-based electron transport layer for high-performance p-i-n perovskite solar cells

The objective of this study was to comprehensively investigate and compare PCBM/ZnO and C60/BCP-based electron transport layers (ETLs) (well recognized as representative ETLs) between perovskite and metal electrode in perovskite solar cells (PeSCs) for high-performance p-i-n structure PeSCs. Their film characteristics and their effects on solar cell performances were studied. When PCBM/ZnO was used as ETL material, the PCE of PeSCs was 19.36 %, which was higher than the PCE of 17.10 % when C60/BCP was used possibly due to more efficient charge recombination reduction and charge extraction shown in PCBM/ZnO-based devices. However, in terms of stability (air, light-soaking, and heat), C60/BCP-based devices showed higher stability than PCBM/ZnO-based devices.

Vacuum‐Assisted Laminating Preparation for Carbon Film Electrode in Perovskite Solar Cells

As an alternative to an evaporated metal top electrode, the carbon film electrode has been successfully applied to small‐area rigid and flexible perovskite solar cells by a pressing transfer method. However, the plate‐to‐plate laminating process for the carbon film electrodes deposition has some shortcomings, such as the uneven and uncertain actual loaded pressure on device. Herein, the carbon film‐based top electrode is laminated onto the perovskite device via a vacuum‐assisted pressing technique with an automatic solar panel laminator. Compared with manual and pneumatic plate pressing, the vacuum laminating process can reduce the roughness of the carbon film and increase the contact area under relatively low working pressure. Consequently, the perovskite solar cells with vacuum laminated carbon electrodes can achieve a relatively high efficiency of 18.3% and exhibit application prospect for reproducible mass fabrication.

In situ growth of graphene on both sides of a Cu–Ni alloy electrode for perovskite solar cells with improved stability

The instability of rear electrodes undermines the long-term operational durability of efficient perovskite solar cells. Here, a composite electrode of copper–nickel (Cu–Ni) alloy stabilized by in situ grown bifacial graphene is designed. The alloying makes the work function of Cu suitable for regular perovskite solar cells. Cu–Ni is the ideal substrate for preparing high-quality graphene via chemical vapour deposition, which simultaneously protects the device from oxygen, water and reactions between internal components. To rivet the composite electrode with the semi-device, a thermoplastic copolymer is applied as an adhesive layer through hot pressing. The resulting devices achieve power conversion efficiencies of 24.34% and 20.76% (certified 20.86%) with aperture areas of 0.09 and 1.02 cm2, respectively. The devices show improved stability: 97% of their initial efficiency is retained after 1,440 hours of a damp-heat test at 85 °C with a relative humidity of 85%; 95% of their initial efficiency is retained after 5,000 hours at maximum power point tracking under continuous 1 sun illumination.

Photovoltaic Properties of ZnO Films Co-Doped with Mn and La to Enhance Solar Cell Efficiency.

In the present investigation, ZnO films co-doped with Mn and La were synthesized by the sol–gel technique. XRD analysis revealed that ZnO had a hexagonal structure. Mixed hexagonal and cubic phases appeared in ZnO containing Mn (1%) and La (1.5%). The grain size, d-spacing, unit cell, lattice parameters, atomic packing fraction, volume, strain, crystallinity, and bond length of co-doped ZnO films were determined as a function of doped ion contents. Through UV analysis, it was found that pristine ZnO had Eg = 3.5 eV, and it decreased when increasing the doping concentration, reaching the minimum value for the sample with 1% Mn and 1% La. The optical parameters of the films, such as absorption, transmittance, dielectric constants, and refractive index, were also analyzed. DSSCs were fabricated using the prepared ZnO films. For pure ZnO film, the values were: efficiency = 0.69%, current density = 2.5 mAcm−2, and open-circuit voltage = 0.56 V. When ZnO was co-doped with Mn and La, the efficiency increased significantly. DSSCs with a ZnO photoanode co-doped with 1% Mn and 1% La exhibited maximum values of Jsc = 4.28 mAcm−2, Voc = 0.6 V, and efficiency = 1.89%, which is 174% better than pristine ZnO-based DSSCs. This material is good for the electrode of perovskite solar cells.

Recent Developments in Upscalable Printing Techniques for Perovskite Solar Cells.

Just over a decade, perovskite solar cells (PSCs) have been emerged as a next‐generation photovoltaic technology due to their skyrocketing power conversion efficiency (PCE), low cost, and easy manufacturing techniques compared to Si solar cells. Several methods and procedures have been developed to fabricate high‐quality perovskite films to improve the scalability and commercialize PSCs. Recently, several printing technologies such as blade‐coating, slot‐die coating, spray coating, flexographic printing, gravure printing, screen printing, and inkjet printing have been found to be very effective in controlling film formation and improving the PCE of over 21%. This review summarizes the intensive research efforts given for these printing techniques to scale up the perovskite films as well as the hole transport layer (HTL), the electron transport layer (ETL), and electrodes for PSCs. In the end, this review presents a description of the future research scope to overcome the challenges being faced in the printing techniques for the commercialization of PSCs.