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Perovskite solar cells (PSCs) offer a number of key advantages over silicon solar cells. These include their low-cost materials, high efficiency, simplicity of fabrication, and inexpensive manufacturing techniques. To commercialize PSCs, there are many methods to develop the quality of the cells, one of them being printing techniques. Different printing techniques deposition have been developed for the perovskite solar cell, such as blade coating, slot die coating, inkjet printing, screen printing, spray coating, flexographic printing, and gravure printing. These techniques have a substantial impact on the performance of PSCs and controlling film formation to commercialize PSCs. This review summarizes a comprehensive overview of various deposition printing techniques used to fabricate PSCs during different years and different techniques, such as using different preparation methods, novel drying techniques, and ink engineering. In addition, the challenges that are faced by using these, such as material stability, reproducibility of printing processes, and cost-effectiveness techniques, are reviewed. Future research should focus on optimizing printing techniques to improve the stability and scalability of PSCs. Exploring novel perovskite materials, deposition techniques, and innovative fabrication methods may further enhance the PSCs and facilitate their commercialization. [ABSTRACT FROM AUTHOR]

Silver nanowire transparent conductive films (AgNW TCFs), as the novel transparent electrode materials replacing ITO, are anticipated to be applied in numerous optoelectronic devices, and slot-die coating is currently acknowledged as the most suitable method for the mass production of large-sized AgNW TCFs. In this study, sodium carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), as film-forming aids, and AgNWs, as conductive materials, were utilized to prepare a specialized AgNW ink, and a slot-die coating is employed to print and prepare AgNW TCFs. The optoelectrical properties of AgNW TCFs are optimized by adjusting the compositions of AgNW ink and the process parameters of slot-die coating. The suitable compositions of AgNW ink and the optimal parameters of slot-die coating are a CMC type of V, a PVA volume of 1 mL, a AgNW volume of 1.5 mL, a volume ratio of 30 and 45 nm AgNWs (2:1), and a coating height of 400 μm. The resultant AgNW TCFs achieve excellent comprehensive optoelectronic performance, with a sheet resistance of less than 50 Ω/sq, a visible light transmittance exceeding 92%, and a haze below 1.8%. This research provides a valuable approach to producing AgNW TCFs on a large scale via the slot-die coating. [ABSTRACT FROM AUTHOR]

Reduced‐dimensional perovskites (RDPs) have advanced perovskite optoelectronic devices due to their tunable energy landscape, structure, and orientation. However, the origin of structural and photophysical property changes when moving from low‐dimensional to high‐dimensional RDPs remains to be understood. This study systematically reveals structural and photophysical properties of slot‐die‐coated Dion‐Jacobson (DJ) and Ruddlesden‐Popper (RP) RDPs with different dimensionalities. RP RDPs with lower dimensionality (n = 2) exhibit a dominant n = 2 phase, preferential out‐of‐plane orientation, and longer charge carrier lifetime compared with DJ RDPs. In addition, the formation kinetics of RDPs with higher dimensionality (n = 4) are unraveled by in situ X‐ray scattering, showing the favorable formation of the lower‐n phase in RP RDPs. The formation of these lower‐n phases is thermodynamically and stoichiometrically favored, while these phases are likely in the form of an "intermediate phase" which bridges the 3D‐like and lower‐n phases in DJ RDPs. DJ RDPs with higher dimensionality demonstrate comparable phase purity, preferential orientation, spatially vertical phase homogeneity, and longer charge carrier lifetime. As such, DJ‐based perovskite solar cells (PSCs) (n = 4) demonstrate better photostability under operational conditions than RP‐based PSCs. Thus, the work paves the way for the utilization of RDPs to upscale PSCs. [ABSTRACT FROM AUTHOR]

Solvent additives enable the efficient modification of the morphology to improve the power conversion efficiency (PCE) of organic solar cells. However, the impact of solvent additive selectivity on the film morphology and formation kinetics is still unclarified. Herein, this work investigates two solvent additives, 1‐chloronaphthalene (1‐CN) and tetralin, characterized by their varying selectivity for the polymer donor (PBDB‐T‐2F) and the non‐fullerene small molecule acceptor (BTP‐C3‐4F). Specifically, 1‐CN exhibits superior solubility for BTP‐C3‐4F over PBDB‐T‐2F, whereas tetralin shows the opposite trend. The blend films with and without solvent additives are fabricated with the slot‐die coating at ambient conditions. Both solvent additives can promote larger phase separation and increase the size of crystals of the selectively dissolved component. In situ grazing‐incidence wide‐angle X‐ray scattering and UV–vis absorption spectra during printing unveil two distinct kinetic processes induced by 1‐CN and tetralin, leading to large‐sized crystals. 1‐CN can prolong the liquid‐solid phase separation to provide sufficient time for the BTP‐C3‐4F crystal growth but suppress the crystal growth of PBDB‐T‐2F. Tetralin can swell PBDB‐T‐2F and break down BTP‐C3‐4F crystals at the same time. Upon thermal annealing, the oversized crystals triggered by both solvent additives can be optimized to an appropriate size, resulting in an enhanced PCE. [ABSTRACT FROM AUTHOR]

As the world edges closer to perovskite solar cell (PSC) commercialization, state‐of‐the‐art materials and processes become publicized to a much lesser degree. From current insights into perovskite industry standards, slot‐die coating is the number one method for fabricating the perovskite layer. Other significant layers can be done using varying techniques. Hence, in this review article, all 115 existing slot‐die‐based PSC publications to date together with related literature are crystallized to set stages for future scalable perovskite research. Through investigation of the effects of materials, processes, and structures on performance, stability, and cost of slot‐die coating is presented. In the end, power output x operating lifetime per cost is the most influential factor for market consideration. The roll‐to‐roll compatibility of the slot‐die coating together with low‐cost materials and lean processes present a cost‐effective strategy for successful commercialization. [ABSTRACT FROM AUTHOR]

Organic electroactive materials, particularly semiconducting polymers, are at the forefront of emerging organic electronics. Among the plethora of unique features, the possibility to formulate inks out of these materials is particularly promising for the large‐scale manufacturing of electronics at lower cost on a variety of soft substrates. While solution deposition of semiconducting materials is promising for developing printed electronics, the environmental footprint of the materials and related devices needs to be considered to achieve sustainable manufacturing. Towards the development of greener printed electronics, this work investigates the utilization of a non‐toxic, environmentally‐friendly solvent, namely branched polyethylene (BPE), to formulate semiconducting inks. Focusing on a diketopyrrolopyrrole‐based (DPP) semiconducting polymer, shellac as dielectric, and BPE as the solvent, solutions were prepared in different concentrations and their rheological properties were characterized. Then, printing on polyethylene terephthalate (PET) substrates using two different techniques was performed to fabricate organic field‐effect transistors (OFETs). Both printing techniques yielded OFETs with good performance and device characteristics, averaging approximately 10−2 and 10−4 cm2 V−1 s−1, respectively, for slot‐die coating and direct‐ink writing deposition. Notably, despite some difference in threshold voltages, OFETs produced via slot‐die coating and direct‐ink writing showed comparable charge mobilities to previously reported OFETs prepared from similar materials, particularly those prepared on silicon dioxide wafers. Overall, this work confirms the suitability of BPE to formulate semiconducting inks to develop printed electronics in a greener manner. The printing methodology developed in this work also open new avenues for the design of functional printed electronics and related technologies. [ABSTRACT FROM AUTHOR]

Upscaling the perovskite solar cell (PSC) while avoiding losses in the power conversion efficiency presents a substantial challenge, especially when transitioning from ≤1 cm2 cells to ≥10 cm2 modules. In addition to the fabrication of key functional layers, scalable technologies for surface passivation, considered indispensable for achieving high‐performance PSCs, are urgently required. However, studies on this topic remain limited. In this study, an industry‐ready slot‐die coating method for the effective passivation of perovskite films as a practical alternative is developed to the spin‐coating procedures commonly used in research. The coating conditions and molecular structure of the passivation agent are systematically optimized to achieve high‐quality film morphology and substantially suppress interface recombination. 2‐chloro‐5‐(trifluoromethyl)‐phenylammonium bromide exhibited the best results, improving the open‐circuit voltage of cells and subcells in a module by 80 ± 4 and 72 ± 10 mV, respectively. Correspondingly, the larger‐area (active area: 10 cm2) modules sustained the highest efficiency of 21.9% under simulated 1‐sun irradiation. The encapsulated devices retained 94% of their initial performances after 750 h of continuous operation. The proposed surface‐passivation slot‐die technology is compatible with high‐throughput processes and is employable for large‐scale PSC fabrication. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable energy solutions has made the development of scalable, efficient, and cost‐effective perovskite solar cells (PSCs) increasingly important. Wide‐bandgap perovskites (WB‐PSCs) stand out due to their efficiency in low‐light conditions and their use in tandem solar cells. WB‐PSCs are currently behind conventional PSCs in upscaling, with limited success in printing wide bandgap PSCs. Developing upscaling methods is essential to fully realize their potential in the renewable energy sector. This research addresses the development of roll‐to‐roll (R2R) slot‐die coating of Cs0.05FA0.95PbBr3‐based WB‐PSCs by focusing on improving the film formation process and ink formulation. By adding optimal concentration of CsBr and performing in situ characterization, we obtained Cs0.05FA0.95PbBr3 films with enhanced morphology and crystallinity in ambient conditions (50% RH), without inducing secondary phase formation. In addition, slot‐die coating defects are eliminated through introducing DMSO: Butanol (9:1) solvent system. The R2R coated wide‐bandgap PSCs reaches a power conversion efficiency (PCE) of up to 8.97% under 1‐sun conditions and 18.3% PCE under indoor conditions. The corresponding R2R coated modules with a 5 × 5 cm2 active area achieve a PCE of 5.8%, representing a crucial step towards the high‐throughput, cost‐effective production of perovskite solar modules. [ABSTRACT FROM AUTHOR]

In recent years, third-generation solar cells have experienced a remarkable growth in efficiency, making them a highly promising alternative energy solution. Currently, high-efficiency solar cells often use top electrodes fabricated by thermal evaporation, which rely on high-cost and high energy-consumption vacuum equipment, raising significant concerns for mass production. This study develops a method for fabricating silver electrodes using the screen-printing process, aiming to achieve solar cell production through an all-solution coating process. By selecting appropriate blocking-layer materials and optimizing the process, we have achieved device efficiencies for organic photovoltaics (OPVs) with screen-printed silver electrodes comparable to those with silver electrodes fabricated by thermal evaporation. Furthermore, we developed a method to cure the silver ink using near-infrared (NIR) annealing, significantly reducing the curing time from 30 min with hot air annealing to just 5 s. Additionally, by employing sheet-to-sheet (S2S) slot-die coating, we scaled up the device area and completed module development, successfully verifying stability in ambient air. We have also extended the application of screen-printed silver electrodes to perovskite solar cells (PSCs). [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are the most rapidly advancing photovoltaic technology in terms of power conversion efficiency. An efficiency of 26.1% was achieved in a decade, which is on par with the efficiency of very mature silicon panels. However, PSC commercialisation is partly hindered by the difficulty of scaling these devices without efficiency loss, mostly due to the increasing sheet resistance of the transparent conductive layer substrates and the nonuniformity of the layers when deposited across large areas. Therefore, it is crucial for the commercialisation of PSCs to implement easily scalable deposition processes with low material waste and compatibility with roll-to-roll (R2R) processes to reduce manufacturing costs. Slot-die coating can meet all these requirements, allowing for great uniformity over large areas. The most recent developments in PSC upscaling using slot-die coating as the main deposition process, along with its extension to the R2R process, are reviewed, including a thorough discussion of the slot-die coating process and the theory behind its operating limits. In fact, R2R coating is a very promising strategy for PSC industrialisation, since all processing steps use low-cost materials and scalable processes at temperatures lower than 120 °C, allowing the cost-effective and high-throughput production of PSC devices. [ABSTRACT FROM AUTHOR]

Solution‐coating processes are promising methods to form active layers with low‐cost input in the industrial development of perovskite solar devices. Among available coating processes, of particular interest are those capable of producing uniform coatings with small defect distribution over large areas at high speeds, referred to as scalable methods. Slot‐die coating is one of these methods. It involves the meniscus coating of liquids or solutions over a static or moving substrate. This review discusses recent advances in slot‐die coating of active layers used in perovskite solar cells (PSCs) and modules (PSMs). Various strategies to control ink spreading over substrates, wet film drying, and post‐coating crystallization of light‐absorbing perovskite layer are outlined along with different approaches and materials used in post‐deposition defects healing. Then, commonly used solvents for perovskite ink formulation are analyzed based on their specific rheology and potential effect on human health and equipment safety. Also, precursor materials, solvents, and strategies to obtain desirable properties and morphology in the slot‐die coating of charge‐transporting layers are discussed. Lastly, an analysis of the performance of slot‐die coated perovskite solar mini‐modules and future perspectives on this topic conclude this review. [ABSTRACT FROM AUTHOR]

The development of industrially relevant deposition processes for efficient, stable, and inexpensive charge extracting layers is crucial for the commercialization of perovskite solar cells (PSCs). This work demonstrates, for the first time, the deposition of copper thiocyanate (CuSCN) as a low‐cost and reliable hole‐transport layer using slot‐die coating. Methyl ethyl sulfide is thereby used as an asymmetric cosolvent to significantly increase the solubility of CuSCN in the utilized slot‐die ink compared to traditional pure diethyl sulfide‐based solutions. Optimized CuSCN inks allow for the deposition of CuSCN layers on 5 × 10 cm2 substrates with a wide range of thicknesses. Multidimensional imaging photoluminescence techniques are used to investigate the uniformity of the CuSCN thin films deposition as well as the influence of the solvent on charge losses. Finally, the CuSCN slot‐die deposition is integrated into a fully upscalable PSC fabrication process showing 19.1% power conversion efficiency for small laboratory cells and 14.7% for 9 cm2 minimodules. Furthermore, semitransparent minimodules retain 80% of their initial efficiency after 500 h of constant illumination. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) and chitosan (Cht) have been studied extensively for oxygen and water vapour barrier coatings in biodegradable, compostable or recyclable paper packaging. However, rare studies have been performed by using scalable, inexpensive, and fast continuous slot-die coating processes, and none yet in combination with fast' and high-throughput near-infrared (NIR) light energy drying. In this frame, we studied the feasibility of a moderately concentrated (11 wt%) anionic CNC and (2 wt%) cationic Cht coating (both containing 20 wt% sorbitol related to the weight of CNC/Cht), by using plain and pigment pre-treated papers. The effect of coating parameters (injection speed, dry thickness settings) were investigated on coating quantity (dry weight, thickness) and homogeneity (coverage), papers' structure (thickness, grammage, density), whiteness, surface wettability, barrier (air, oxygen and water vapour) properties and adhesion (surface strength). The coating homogeneity was dependent primarily on the suspensions' viscosity, and secondarily on the applied coating parameters, whereby CNCs could be applied at 1–2 times higher injection speeds (up to 80 mL/min) and versatile coating weights, but required a relatively longer time to dry. The CNCs thus exhibited outstanding air (4.2–1.5 nm/Pa s) and oxygen (2.7–1.1 cm3 mm/m2 d kPa) barrier performance at 50% RH and 22–33 g/m2 deposition, whereas on top deposited Cht (3–4 g/m2) reduced its wetting time and improved the water vapour barrier (0.23–0.28 g mm/m2 d Pa). The balanced barrier properties were achieved due to the polar characteristic of CNCs, the hydrophobic nature of Cht and the quantity of the applied bilayer coating that can provide sustainable paper-based packaging. [ABSTRACT FROM AUTHOR]

Continuous pin-hole free FA0.78Cs0.22Pb(I0.85Br0.15)3 films are deposited by gas-assisted slot-die printing under ambient conditions using DMF/DMSO based ink containing Formamdinium Acetate additive. Using a binary solvent mixture of DMF and DMSO is effective in eliminating the non-perovskite phase that occurs when DMF alone is used. Print-speed, gas flow rate and chuck temperature are optimized to realize homogeneous films with constant bandgap (1.63 eV) over large substrates (2″ × 4″). The perovskite films prepared using two solvents DMF and DMF: DMSO (9:1) were incorporated in single junction devices. The resulting devices show improved fill factor with improved power conversion efficiency. [ABSTRACT FROM AUTHOR]

Mixed halide perovskite nanocrystals in the form of cesium/formamidinium lead triiodide ((Cs:FA)PbI3) offer great potential for efficient and stable solar cells. To date, large‐scale production with roll‐to‐roll compatible deposition methods remains difficult and requires detailed research on each involved processing step. Here, a proof‐of‐concept study about slot‐die coating (printing) the active layer of (Cs:FA)PbI3‐based nanocrystal solar cells is presented. Structural and morphological changes during ligand exchange of long‐chain oleic acid and oleylamine by Pb(NO3)2, and top‐layer FAI passivation are investigated. Ligand exchange improves the processability of the nanocrystal layer and enhances charge transport. It also changes texture from face‐on toward edge‐on orientation as grazing‐incidence X‐ray scattering studies indicate. Ligand exchange and FAI passivation redshift photoluminescence and prolong charge carrier lifetime in the printed nanocrystal films. The proof‐of‐concept feasibility of printing metal halide perovskite nanocrystal films for solar cells is shown by building 20 devices with a median power conversion efficiency of 6.39%. [ABSTRACT FROM AUTHOR]

In fabricating functional layers, including thin-film transistors and conductive electrodes, using roll-to-roll (R2R) processing on polymer-based PET film, the instability of the slot-die coating meniscus under a high-speed web impedes functional layer formation with the desired thickness and width. The thickness profiles of the functional layers significantly impact the performance of the final products. In this study, we introduce an electrohydrodynamic (EHD)-based voltage application module to a slot-die coater to ensure the uniformity of the cross-machine direction (CMD) thickness profile within the functional layer and enable a stable, high-speed R2R process. The module can effectively control the spreadability of the meniscus by utilizing variations in the surface tension of the ink. The effectiveness of the EHD module was experimentally verified by applying a high voltage to a slot-die coater while keeping other process variables constant. As the applied voltage increases, the CMD thickness deviation reduces by 64.5%, and the production rate significantly increases (up to 300%), owing to the formation of a stable coated layer. The introduction of the EHD-based application module to the slot-die coater effectively controlled the spreadability of the meniscus, producing large-area functional layers. [ABSTRACT FROM AUTHOR]

In the battery industry, very thin primer layers are used to improve electrode adhesion on substrates or act as blocker layers to prevent corrosion in case of aqueous cathodes. For these material configurations, high-speed coating is mandatory to ensure the economic viability of the process. One way to realize high-speed coating is a set-up including a slot die and a vacuum box to stabilize the coating bead. Knowledge and prediction of the coating window of thin wet film thicknesses is crucial to design the production process. Therefore, the influence of coating gap and viscosity of shear-thinning fluids on the coating window is investigated with the help of various model fluids. In addition, a prediction model for the calculation of the coating window for high-speed slot-die coating with vacuum box is developed. This model is shown to be valid for the prediction of the coating window for the investigated material systems and coating gaps over the investigated range of coating speeds up to 500 m min−1. For a material system, which corresponds to a real material system for adhesive primer coatings, it is possible to reach a target wet film thickness of 20–25 µm. This would correspond to a layer thickness of 0.5 µm for a solid content of 2–2.5 wt%. [ABSTRACT FROM AUTHOR]

The slot-die coating is the most commonly used manufacturing method for producing lithium-ion battery electrodes. However, how to achieve high surface consistency for electrodes still confronts one challenge. In this research, the slot coating processes with different die lip configurations were carefully investigated using numerical and experimental methods. The motion pattern, internal flow structure of the coating bead, and coating uniformity were explored during the coating process of lithium battery cathode slurry. The low-flow limit at different coating gaps was also determined by combining the viscous capillary model and numerical methods, which was in good agreement with experimental results. The results showed that a smaller coating gap controlling the upstream meniscus between the upstream die lip and slot exit was favorable to the coating uniformity. For the same thickness films, a larger coating gap was apt to increase formation of edge defects. However, the coating speed had little effect on the edge height. The evolution of flow structure for the coating bead (parabolic–sharp angle–diagonal) under different processes was investigated by tracking the particle trajectories during the coating process. It can provide theoretical guidance for the fabrication of high-quality electrodes. [ABSTRACT FROM AUTHOR]

We reported the comparative studies of the optimization of solution-processable tungsten trioxide (WO3) as a hole transporting layer (HTL) in inverted organic photovoltaics (OPVs) using spin coating, slot-die coating, and spray coating technologies for scaling-up applications. To facilitate the technology's transition into commercial manufacturing, it is necessary to explore the role of scalable technologies for low-cost and efficient device fabrication. We investigated the role of diluting WO3 with isopropanol as an HTL in inverted OPVs to solve the issue of poor wettability of the hydrophobic surface of the PBDB-T: ITIC bulk heterojunction layer. The optimal dilution ratios of WO3 with isopropanol were 1:4, 1:4 and 1:8 with spin coating, slot-die coating and spray coating techniques, respectively. We evaluated the device performance by conducting a current density–voltage (J-V) analysis, incident photon-to-current conversion efficiency (IPCE) measurements, and ultraviolet–visible (UV-Vis) absorbance spectra for various WO3 concentrations. The J-V characteristics revealed that slot-die coating resulted in the highest performance, followed by the spray coating technology. We further investigated the impact of the annealing temperature on device performance for both slot-die- and spray-coated diluted WO3. The highest device performance was achieved at an annealing temperature of 120 °C for both coating technologies. This research offers valuable insights into the scalable fabrication of inverted OPV devices, paving the way for cost-effective and efficient large-scale production. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSC) are emerging technologies that have shown continuous improvement in power conversion efficiency (PCE) and stability. However, a very important aspect that has been seldom considered is the reproducibility of PCE of PSC devices. It is possible to achieve PCE from 10.21% to 17.05% using scalable slot‐die‐coating technique. However, a spatial distribution of performance is clearly observed for device samples on a 4 × 4 cm substrate. The relatively low PCE is mainly coming from the losses of electrical mechanism. To have in‐depth understanding of the losses, the dominant loss analysis techniques including numerical simulations are used to explore the mechanism. In the results, it is indicated that a part of efficiency decrease is due to the increase of bulk defect density which linearly changes with the quality of the perovskite layer and related to recombination process. However, extremely high‐charge‐carrier transportation losses are found at the HTL/perovskite interface that are related to the Fermi‐level pinning mechanism for low‐efficiency device. The result of physics insight of perovskite solar cells leads to a strategy, where chemical passivation technique is used to achieve the PCE from 13.81% to 18.07% for the batch of devices with good reproducibility. [ABSTRACT FROM AUTHOR]

Despite the rapid scale-up of battery production which could be observed the last years, various challenges remain in electrode production. In particular, the high scrap rates of up to 40 % during the coating process of the electrodes offer enormous potential in terms of economic and ecological aspects. To counter these problems, a system concept was developed that can react autonomously to process conditions and thus reduce scrap. For this purpose, with the gap distance and the angle of attack deliberately two parameters are varied during slot-die coating, which react quickly and furthermore do not affect the productivity of the system. By adapting the position of the slot-die, it is possible to achieve an optimum operating point in the coating window and thus improve the quality of the results without regulating the volume flow or the web speed. The aim is both to shorten the start-up process by a fast and precise correction of the slot-die position on the basis of the coating result and to increase the quality in the adjusted operation. With the help of the corresponding measuring technology and the control based on the coating result, the processing of slurries with fluctuating fluid properties or the processing of new recipes is simplified and possible without manual intervention. The concept is possible for existing plants as well as for new plants. [ABSTRACT FROM AUTHOR]

The slot-die coating is recognized as the most compatible method for the roll-to-roll (R2R) processing of large-area flexible organic solar cells (OSCs). However, the photovoltaic performance of the large-area flexible all-polymer solar cells was significantly lagging behind that of polymer donors with small molecule non-fullerene acceptors devices. In this work, the 1 cm2 flexible device of an all-polymer system, PTQ10:PYF-T-o, fabricated by slot-die coating, achieves an excellent efficiency of 11.24% via controlling the coating temperatures. It is found that, compared with the donor, the crystallinity of PYF-T-o plays a crucial role in device performance. The all-polymer flexible devices show superior mechanical bending stability, maintaining an efficiency of over 95% of the initial value during a 1000-cycle bending test. [ABSTRACT FROM AUTHOR]

The causes of coating irregularities in high-speed slot-die coating of catalyst slurries for polymer electrolyte fuel cells (PEFCs) have not been determined. Accordingly, in this study, slot-die-coating experiments and computer simulations of two-phase gas–liquid flow were conducted to explore coating instability in the high-speed coating of PEFC catalyst slurries applied through slot-die coating. The results obtained from experiments and simulations were consistent. A thinner target layer and a faster coating, causing non-uniform coating. This is caused by movement of the gas–liquid interface on the upstream side and side of the die, which entraps the gas phase. Viscosity and surface tension are important, and a lower ethanol content in the solvent increases surface tension and lowers viscosity, improving coating stability. [Display omitted] • PEFC catalyst slurry coating uniformity studied through experiments and simulations. • Results were consistent across experiments and simulations. • Coating is non-uniform at high speed, low thickness, and high ethanol ratio. • The coating occurs in a region with weak non-Newtonian behavior. [ABSTRACT FROM AUTHOR]

The next technological step in the exploration of metal‐halide perovskite solar cells is the demonstration of larger‐area device prototypes under outdoor operating conditions. The authors here demonstrate that when slot‐die coating the halide perovskite layers on large areas, ribbing effects may occur but can be prevented by adjusting the precursor ink's rheological properties. For formamidinium lead triiodide (FAPbI3) precursor inks based on 2‐methoxyethanol, the ink viscosity is adjusted by adding acetonitrile (ACN) as a co‐solvent leading to smooth FAPbI3 thin‐films with high quality and layer homogeneity. For an optimized content of 46 vol% of the ACN co‐solvent, a certified steady‐state performance of 22.3% is achieved in p‐i‐n FAPbI3‐perovskite solar cells. Scaling devices to larger areas by making laser series‐interconnected mini‐modules of 12.7 cm2, a power conversion efficiency of 17.1% is demonstrated. A full year of outdoor stability testing with continuous maximum power point tracking on encapsulated devices is performed and it is demonstrated that these devices maintain close to 100% of their initial performance during winter and spring followed by a significant performance decline during warmer summer months. This work highlights the importance of the real‐condition evaluation of larger area device prototypes to validate the technological potential of halide perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are an attractive emerging photovoltaic technology due to their high‐performance while being made by low‐cost fabrication processes. The most efficient PSCs are small area and made by nonscalable coating method in an inert atmosphere, but these sizes and fabrication conditions are commercially irrelevant. Herein, fabrication of PSCs is reported using only scalable methods, that is, slot‐die coating and blade coating methods, all in ambient air. The tolerance to relaxed fabrication conditions is enabled by the use of hydrated nonhalogenated lead source. Resurfacing strategy is then introduced to suppress charge carrier nonradiative recombination and obtained an efficiency of 19.91% for rigid and 17.4% for flexible PSCs by all‐scalable fabrication. To the best of our knowledge, these are the highest efficiencies for n–i–p structured MAPbI3‐based PSCs in ambient air using all‐scalable method to date. The devices showed excellent tolerance to oxygen and moisture (ISOS‐D‐1) as well as stable maximum power point operation following burn in a dry air glove box (relative humidity ≈ 20%) without encapsulation. [ABSTRACT FROM AUTHOR]

We fabricate polymer solar cells (PSCs) and modules by sheet‐to‐sheet slot‐die coating under air environment based on halogen‐free host solvent. How to upscale small‐area PSC to large‐area PSC module is demonstrated here. The opaque module exhibits the most superior performance among the slot‐die‐coated modules reported. The scaling of both the semitransparent top electrode and PSC module is a challenge due to the complex difficulties. In this study, the semitransparent MoO3/Ag/MoO3 top electrode is successfully upscaled to be in the large‐area semitransparent PSC module. Ag layer thickness as reflector in the tri‐layer electrode is used to tune the trade‐off between transmittance, conductivity, and the light absorption in the active layer. The matching combination of transmittance, absorption spectra of MoO3/Ag/MoO3 top electrode, and active layer is a main key of our approach greatly improving photovoltaic and optical performance. The power conversion efficiencies (PCEs) of the semitransparent PSC modules with Ag thickness of 25, 20, and 15 nm are 7.1%, 5.9%, and 4.4%, respectively. The corresponding average visible transmittance (AVT) values are 20.5%, 28.3%, and 36.1%, respectively. The transmittance values at 550 nm are ranging from 24% to 40%. According to the review of all the reported semitransparent modules (>10 cm2), our modules demonstrate the excellent trade‐off performance about two times better than the large‐area semitransparent PSC modules currently reported either based on the similar PCEs or AVTs. [ABSTRACT FROM AUTHOR]

Carbazole‐ and fluorene‐substituted benzidine blocks have been functionalized with two different solubilizing pendant groups, in order to enhance the material's solubility in greener solvents. Preserving the optical and electrochemical properties, the aromatic function and substitution showed an important influence on the solvent affinity, achieving concentrations up to 150 mg/mL in o‐xylenes for the glycol‐containing materials and decent solubility in alcohols for the compounds functionalized with ionic chains. The latter solution proved to be ideal for the preparation of luminescence slot‐die coating film on top of flexible‐substrates up to 33 cm×2 cm. As a proof of concept, the materials have been implemented in different organic electronic devices, highlighting the low turn‐on voltage (4 V) presented by organic light‐emitting diodes (OLEDs), which is comparable with vacuum‐processed devices. A structure‐solubility relationship and a synthetic strategy are disentangled in this manuscript to tailor organic semiconductors and adapt their solubility towards the desired solvent and application. [ABSTRACT FROM AUTHOR]

Energy shortage has become a global issue in the twenty-firt century, as energy consumption grows at an alarming rate as the fossil fuel supply exhausts. Perovskite solar cells (PSCs) are a promising photovoltaic technology that has grown quickly in recent years. Its power conversion efficiency (PCE) is comparable to that of traditional silicon-based solar cells, and scale-up costs can be substantially reduced due to its utilization of solution-processable fabrication. Nevertheless, most PSCs research uses hazardous solvents, such as dimethylformamide (DMF) and chlorobenzene (CB), which are not suitable for large-scale ambient operations and industrial production. In this study, we have successfully deposited all of the layers of PSCs, except the top metal electrode, under ambient conditions using a slot-die coating process and nontoxic solvents. The fully slot-die coated PSCs exhibited PCEs of 13.86% and 13.54% in a single device (0.09 cm2) and mini-module (0.75 cm2), respectively. [ABSTRACT FROM AUTHOR]

A roll-to-roll manufacturing system performs printing and coating on webs to mass-produce large-area functional films. The functional film of a multilayered structure is composed of layers with different components for performance improvement. The roll-to-roll system is capable of controlling the geometries of the coating and printing layers using process variables. However, research on geometric control using process variables is limited to single-layer structures only. This study entails the development of a method to proactively control the geometry of the upper coated layer by using the lower-layer coating process variable in the manufacture of a double-coated layer. The correlation between the lower-layer coating process variable and upper coated layer geometry was examined by analyzing the lower-layer surface roughness and spreadability of the upper-layer coating ink. The correlation analysis results demonstrate that tension was the dominant variable in the upper coated layer surface roughness. Additionally, this study found that adjusting the process variable of the lower-layer coating in a double-layered coating process could improve the surface roughness of the upper coating layer by up to 14.9%. [ABSTRACT FROM AUTHOR]

Understanding and reducing edge elevations at the lateral edges are crucial aspects to reduce reject rates during electrode production for lithium‐ion batteries (LIB). Herein, different process conditions to reduce edge elevations at the lateral edges of water‐based, shear‐thinning coatings in the production of LIB electrodes are presented. The reduction of edge elevations is transferred from state‐of‐the‐art electrodes to high‐capacity electrodes. The developed process configuration greatly reduces reject caused by cutting off the edge areas in the industrial roll‐to‐roll process for electrode production. Compared with state‐of‐the art electrodes, the reject rate for high‐capacity electrode production is significantly higher because the edge geometry in crossweb direction of the electrodes is wider. An optimization can be achieved by a combined adjustment of the coating gap and the slot‐die angle to the substrate (angle of attack) to affect the pressure field in the coating bead. Therefore, a systematic investigation and optimization of these process parameters are presented. In addition, the investigation of the process stability of the coating is required. Based on this optimization, a reduction of edge elevations for high‐capacity electrode coatings (5 mAh cm−2) of 69% and ultrathick high‐capacity electrode coatings (7 mAh cm−2) of 48% is possible. [ABSTRACT FROM AUTHOR]

Large‐scale manufacturing of perovskite solar cells (PSCs) requires the deposition of homogeneous and defect‐free perovskite films on large‐area substrates. Up to now, the knowledge developed for industrial slot‐die processing has not been fully transferred to the perovskite photovoltaic community. Here, the deposition of uniform perovskite layers by slot‐die coating (SDC). Computer fluid dynamics (CFD) simulations, experimental validation, and calculation of industrial uniformity parameters are demonstrated, which enabled to establish processing conditions for SDC of perovskite ink. This approach allowed for obtaining stable cross‐web flow in the slot‐die head resulting in the formation of a stable coating bead yielding uniform perovskite films. The best processing parameters are used for the fabrication of slot‐die‐coated PSCs, which showed a more homogeneous spatial distribution of photovoltaic parameters compared to their spin‐coated counterparts. Better reproducibility observed in device performance is a step forward toward the commercialization of perovskite photovoltaic technology. For the first time, the industrial approach used for the optimization of slot‐die coating is applied for the processing of perovskite inks that have special conditions such as low viscosity and in situ crystallization on the substrate. [ABSTRACT FROM AUTHOR]

Large‐area flexible transparent conductive electrodes (TCEs) featuring excellent optoelectronic properties (low sheet resistance, Rs, at high transparency, T) are vital for integration in transparent wearable electronics (i.e., antennas, sensors, supercapacitors, etc.). Solution processing (i.e., printing and coating) of conductive inks yields highly uniform TCEs at low cost, holding great promise for commercially manufacturing of transparent electronics. However, to formulate such conductive inks as well as to realize continuous conductive films in the absence of percolation issue are quite challenging. Herein, the scalable slot‐die coating of Ti3C2Tx MXene aqueous inks is reported for the first time to yield large‐area uniform TCEs with outstanding optoelectronic performance, that is, average DC conductivity of 13 000 ± 500 S cm−1. The conductive MXene nanosheets are forced to orientate horizontally as the inks are passing through the moving slot, leading to the rapid manufacturing of highly aligned MXene TCEs without notorious percolation problems. Moreover, through tuning the ink formulations, such conductive MXene films can be easily adjusted from transparent to opaque as required, demonstrating very low surface roughness and even mirror effects. These high‐quality, slot‐die‐coated MXene TCEs also demonstrate excellent electrochemical charge storage properties when assembled into supercapacitors. [ABSTRACT FROM AUTHOR]

Slot‐die coating is a promising upscaling fabrication method to promote commercialization in the field of organic solar cells. Herein, the nonfullerene active layer blend of a conjugated polymer PffBT4T‐2OD and a small molecule acceptor EH‐IDTBR, which is printed out of the nonhalogenated solvent 1,2,4‐trimethylbenzene, is studied. The film formation kinetics of the active layer PffBT4T‐2OD:EH‐IDTBR is probed in terms of the temporal evolutions in morphology as well as molecular conformation and aggregation as revealed by in situ grazing‐incidence small angle X‐ray scattering and UV–vis spectroscopy during the film printing process. A five‐regime mesoscale domain growth process is observed in the active layer from the liquid state to the final dry state. The solvent evaporation‐induced domain growth is accompanied with molecular stacking in a distinct J‐type aggregation of the acceptor and a slight H‐type aggregation of the donor molecules. The printed active layers exhibit an edge‐on dominated PffBT4T‐2OD and a face‐on dominated EH‐IDTBR crystallite structure. Compared to the neat PffBT4T‐2OD and EH‐IDTBR films, in the active layer, the crystallite structure deviates slightly in lattice spacing. [ABSTRACT FROM AUTHOR]

Perovskites have already shown potential as active layers in photovoltaic applications. Furthermore, a low-cost and simple solution processing technology allows perovskites to be used in flexible and printed electronics. Perovskite solar cells (PSC) with a back-contact (BC) structure, in which the electrode system is based on a quasi-interdigitated back-contact (QIBC) design, promise to increase the power conversion efficiency (PCE) of devices beyond those that can be obtained using PSCs with a traditional sandwich structure. While the spin-coating technique is used to deposit the perovskite layer of lab-scale BC PSCs, the application of large-area printing techniques to deposit the perovskite layer of such devices is yet to be explored. Therefore, this work demonstrates an application of the slot-die coating technique to print the perovskite active layer of BC PSCs with QIBC electrodes on flexible polymer substrates. The morphology of the obtained perovskite films on QIBC electrodes are investigated and the primary photoelectric parameters of the resulting BC PSCs are measured. The charge carrier recombination processes in the fabricated BC PSCs are investigated and the dominant mechanism for carrier loss in the devices is determined. The findings of the work give an insight into the properties of the slot-die-coated perovskite active layer of BC PSCs and points to exciting new research opportunities in this direction. [ABSTRACT FROM AUTHOR]

Laboratory‐controlled conditions, spin‐coating method, and non‐ecofriendly halogenated solvents that have been employed for higher‐performance organic solar cells (OSCs) are not compatible with large‐scaled, roll‐to‐roll (R2R) manufacturing in ambient conditions. Slot‐die coating is a viable upscaling method, but the investigation of slot‐die‐coated OSCs is still rare, especially OSCs with all functional layers deposited with non‐halogenated solvents in air. Herein, all slot‐die coated devices are successfully manufactured by sequentially slot‐die coating the hole transport layer (PEDOT:PSS), the photoactive layers (PM6 and BTP‐4F‐12 (Y6‐C12)), and the electron transport layer (PFN‐Br). Because of solubility variation of photoactive components in non‐halogenated solvents (o‐Xylene and 2‐methyltetrahydrofuran (2‐MeTHF)), two bilayer‐processed photoactive films have been obtained via different solvent combinations (o‐Xylene/o‐Xylene for PM6 (o‐Xylene)/Y6C12 (o‐Xylene) and o‐Xylene/2‐MeTHF for PM6 (o‐Xylene)/Y6C12 (2‐MeTHF)). Different morphologies of bilayer‐processed photoactive films influence exciton dissociation and charge extraction properties of corresponding devices. Finally, the device hosting o‐Xylene/o‐Xylene processed photoactive film has a superior efficiency (10.6%) than the o‐Xylene/2‐MeTHF processed photoactive film‐based device (7.2%). Differently from device efficiency, the device based on o‐Xylene/2‐MeTHF processed photoactive film exhibits the preferable storage stability. [ABSTRACT FROM AUTHOR]

There inevitably appear dead zones in organic thin films fabricated by sheet-to-sheet slot-die coating because a coating start varies and the recovery time of internal pressure in slot-die head differs for each coating, resulting in poor coating repeatability. Slot-coated thin films within dead zones are thinner or thicker, possibly causing non-uniform light emission from solution-processable organic light-emitting diodes (OLEDs). To tackle it, we have devised an automatic coating start method based on the monitoring of meniscus formation. It automatically starts coatings when the cross-sectional area of meniscus reaches a certain optimal value in such a way that the start of each coating is kept unchanged. It is found that high-viscosity (4800 cPs) polydimethylsiloxane (PDMS) requires a longer time for the internal pressure of slot-die head to reach a steady state than low-viscosity (80 cPs) poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). It can be reduced to a great extent by applying a method of discharging the solution in advance (pre-discharging scheme). Compared with high-viscosity PDMS films, low-viscosity PEDOT:PSS films are shown to have longer dead zones and poorer repeatability due to the fact that the dead zone of relatively thin films varies sensitively to a small change in the coating start timing. With this scheme, we have successfully fabricated a highly uniform OLED device with no dead zones in the emission area. [Display omitted] • Suppression of dead zones in organic thin films fabricated by sheet-to-sheet slot-die coating. • Automatic coating start method based on the monitoring of meniscus formation. • A pre-discharging method required for high-viscosity liquids due to high hydraulic resistance. • Fabrication of thin films with the standard deviation of dead zones as low as 1.59 mm. • No dead zone in 20 mm × 60 mm OLED device with the slot-coated conductive PEDOT:PSS layer. [ABSTRACT FROM AUTHOR]

Abstract Perovskite solar cells (PSCs) have attracted tremendous attention as a promising alternative candidate for clean energy generation. Many attempts have been made with various deposition techniques to scale-up manufacturing. Slot-die coating is a robust and facile deposition technique that can be applied in large-area roll-to-roll (R2R) fabrication of thin film solar cells with the advantages of high material utilization, low cost and high throughput. Herein, we demonstrate the encouraging result of PSCs prepared by slot-die coating under ambient environment using a two-step sequential process whereby PbI2:CsI is slot-die coated first followed by a subsequent slot-die coating of organic cations containing solution. A porous PbI2:CsI film can promote the rapid and complete transformation into perovskite film. The crystallinity and morphology of perovskite films are significantly improved by optimizing nitrogen blowing and controlling substrate temperature. A power conversion efficiency (PCE) of 18.13% is achieved, which is promising for PSCs fabricated by two-step fully slot-die-coated devices. Furthermore, PSCs with a 1 cm2 area yield a champion PCE of 15.10%. Moreover, a PCE of 13.00% is obtained on a flexible substrate by the roll-to-roll (R2R) coating, which is one of the highest reported cells with all layers except for metal electrode fabricated by R2R process under ambient condition.

Abstract Laboratory‐controlled conditions, spin‐coating method, and non‐ecofriendly halogenated solvents that have been employed for higher‐performance organic solar cells (OSCs) are not compatible with large‐scaled, roll‐to‐roll (R2R) manufacturing in ambient conditions. Slot‐die coating is a viable upscaling method, but the investigation of slot‐die‐coated OSCs is still rare, especially OSCs with all functional layers deposited with non‐halogenated solvents in air. Herein, all slot‐die coated devices are successfully manufactured by sequentially slot‐die coating the hole transport layer (PEDOT:PSS), the photoactive layers (PM6 and BTP‐4F‐12 (Y6‐C12)), and the electron transport layer (PFN‐Br). Because of solubility variation of photoactive components in non‐halogenated solvents (o‐Xylene and 2‐methyltetrahydrofuran (2‐MeTHF)), two bilayer‐processed photoactive films have been obtained via different solvent combinations (o‐Xylene/o‐Xylene for PM6 (o‐Xylene)/Y6C12 (o‐Xylene) and o‐Xylene/2‐MeTHF for PM6 (o‐Xylene)/Y6C12 (2‐MeTHF)). Different morphologies of bilayer‐processed photoactive films influence exciton dissociation and charge extraction properties of corresponding devices. Finally, the device hosting o‐Xylene/o‐Xylene processed photoactive film has a superior efficiency (10.6%) than the o‐Xylene/2‐MeTHF processed photoactive film‐based device (7.2%). Differently from device efficiency, the device based on o‐Xylene/2‐MeTHF processed photoactive film exhibits the preferable storage stability.

Organic solar cells (OSCs), as a renewable energy technology that converts solar energy into electricity, have exhibited great application potential. With the rapid development of novel materials and device structures, the power conversion efficiency (PCE) of non-fullerene OSCs has been increasingly enhanced, and over 19% has currently been achieved in single-junction devices. Compared with rigid silicon cells, OSCs have the characteristics of low cost, high flexibility, lightweight, and their inherent solution processability, which enables the devices to be manufactured by using printing technology for commercial applications. In recent years, to maximize the device performance of OSCs, many efforts have been devoted to improving the morphologies and properties of the active layer through various novel printing technologies. Herein, in this review, the recent progress and applications of several popular printing technologies to fabricate high-efficient OSCs are summarized, including blade-coating, slot-die coating, gravure printing, screen printing, inkjet printing, etc. The strengths and weaknesses of each printing technology are also outlined in detail. Ultimately, the challenges and opportunities of printing technology to fabricate OSC devices in industrial manufacturing are also presented. [ABSTRACT FROM AUTHOR]

Upscaling large‐area formamidinium (FA)‐based perovskite solar cells (PSCs) has been considered as one of the most promising routes for the commercial applications of this rising photovoltaics technology. Here, a natural amino acid, phenylalanine (Phe), is introduced to regulate the nucleation and crystal growth process of the large‐scale coating of FA‐based perovskite films. Better film coverage and larger grain sizes are observed after adding Phe. Moreover, it is found that Phe can effectively passivate defects within perovskite films and suppress the nonradiative recombination due to the strong interaction with under‐coordinated Pb2+ ions in the perovskite films. Rigid PSCs based on the blade‐coated perovskite films containing Phe obtain a champion efficiency of 21.95%. The corresponding unencapsulated devices also exhibit excellent ambient stability, retaining 95% of their initial efficiencies after storage in the glovebox at 20 °C for 1000 h. Further, the strategy is applied to fabricate flexible PSCs and modules on polyethylene terephthalate/indium doped tin oxide substrates via slot‐die coating. Phe modified flexible devices achieve outstanding efficiencies of 20.21%, 12.1%, and 11.2% with aperture areas of 0.10, 185, and 333 cm2, respectively. The strategy here has paved a promising way for the large‐scale production of flexible PSCs. [ABSTRACT FROM AUTHOR]

Upscaling large‐area formamidinium (FA)‐based perovskite solar cells (PSCs) has been considered as one of the most promising routes for the commercial applications of this rising photovoltaics technology. Here, a natural amino acid, phenylalanine (Phe), is introduced to regulate the nucleation and crystal growth process of the large‐scale coating of FA‐based perovskite films. Better film coverage and larger grain sizes are observed after adding Phe. Moreover, it is found that Phe can effectively passivate defects within perovskite films and suppress the nonradiative recombination due to the strong interaction with under‐coordinated Pb2+ ions in the perovskite films. Rigid PSCs based on the blade‐coated perovskite films containing Phe obtain a champion efficiency of 21.95%. The corresponding unencapsulated devices also exhibit excellent ambient stability, retaining 95% of their initial efficiencies after storage in the glovebox at 20 °C for 1000 h. Further, the strategy is applied to fabricate flexible PSCs and modules on polyethylene terephthalate/indium doped tin oxide substrates via slot‐die coating. Phe modified flexible devices achieve outstanding efficiencies of 20.21%, 12.1%, and 11.2% with aperture areas of 0.10, 185, and 333 cm2, respectively. The strategy here has paved a promising way for the large‐scale production of flexible PSCs. [ABSTRACT FROM AUTHOR]

Cathode interlayers (CILs) in organic photovoltaics (OPVs) are actively being researched as they are critical for device stability and performance. Herein, N‐annulated perylene diimide with a 2‐ethyl‐hexyl side chain (PDIN‐EH) is demonstrated, which is facile to synthesize as compared with conventional CILs such as PFN‐Br, exhibits solubility, and subsequent processability from ethanol. The PDIN‐EH is evaluated as a CIL in an air‐processed, slot‐die coated OPV consisting of PEDOT:PSS as the hole transport layer, PM6:Y6C12 as the bulk heterojunction, and top silver cathode electrode. All the organic layers are slot‐die coated from green solvents and devices achieve a power convention efficiency of more than 12%, a result that is among the best reported under ambient conditions for printed OPVs. Microscopy images reveal that the PDIN‐EH affords smooth film formation when slot‐die coated on top of PM6:Y6C12 bulk heterojunction for an improved contact with the Ag electrode. Furthermore, the fabrication of large‐area OPV modules on glass and flexible (polyethylene terephthalate) substrates is successfully demonstrated, with five cells connected in series achieving efficiency over 7% and open‐circuit voltage over 3.5 V. Herein, useful guidelines for achieving fully printed organic electronic devices from green solvents at a potential industrial scale are provided. [ABSTRACT FROM AUTHOR]

Petro‐derived organic cathode interlayers (CILs) can modify the tin‐oxide (SnO2) electron transport layer (ETL) in organic photovoltaics (OPVs) to address the energy‐level alignment, charge extraction, and device shelf‐life instability challenges. However, the potential eco‐hazardousness of petro sources used to synthesize such CILs and the toxicity of processing solvents warrant the discovery of sustainable and commercially viable substitutes. Herein, a low‐cost, biocompatible, and water‐processable CIL based on amine‐functionalized cellulose nanocrystals (CNC‐a) is introduced to enhance the performance of OPVs by mitigating surface defects of the SnO2 ETL. X‐ray photoelectron spectroscopy (XPS) reveals a reduction in water traps after SnO2 modification with CNC‐a. The electrical characterization shows that CNC‐a modification improves the conductivity of the SnO2. CNC‐a inhibits charge recombination and improves the charge collection ability leading to power conversion efficiencies (PCEs) of >13% in halogen‐free solvent and air‐processed PBDB‐T‐SF (PM6):BTP‐4F‐12 (Y6‐C12)‐based OPVs. The SnO2/CNC‐a bilayer ETL‐based devices exhibit relatively high shelf‐life device stability. Fully slot‐die‐coated (where SnO2, CNC‐a, and bulk heterojunction [PM6:Y6‐C12] are coated) large area bottom cathode cells (PCE > 10%) are demonstrated, showcasing the utility for scale‐up. This work opens a viable and sustainable pathway to develop bio‐derived materials for scalable OPVs. [ABSTRACT FROM AUTHOR]

The series of electrodes were fabricated by the scalable and manufacturable slot-die coating method for proton exchange membrane fuel cell (PEMFC) application. The inks with different amounts of solids were studied by rheological methods in order to establish a coating window with minimum manufacturing defects. The obtained electrodes were characterized by SEM, AFM, and optical microscopy, which showed that they were uniform and homogeneous with minimum defects. The electrochemical evaluation of the manufactured gas diffusion electrodes (GDE) showed that the main characteristics of the electrodes, like electrochemical surface area, proton resistivity, and double layer capacitance, were found to be close for all samples confirming the reproducibility of the slot-die process. Additionally, we studied the effects of membrane thickness on the performance of the GDE membrane electrode assemblies and determined that a decrease in membrane thickness favored the performance. The obtained results clearly demonstrated the applicability and feasibility of the approach for the Manufacturing of catalyst layers for the fuel cell application with potential for future mass production. [Display omitted] • Pt/C inks with high solid content were formulated. • Scalable Roll-2-Roll approach was used to coat 300 × 22cm electrode. • The electrodes possessed minimal inhomogeneities. • PEM fuel cell tests confirmed promising performance of scaled electrodes. [ABSTRACT FROM AUTHOR]

The dependence of the maximum and minimum wet thicknesses on the coating gap is derived for the slot‐die coating process, under different slot‐die configurations. Analytical expressions for the wet thickness and its derivative with respect to the coating gap are obtained using a simple flow model. The results indicate that, as expected, the minimum wet thickness increases linearly with the coating gap; however, the maximum wet thickness demonstrates a counterintuitive trend of decreasing as the coating gap increases, when a specific slot‐die configuration is assumed. Moreover, the results are also validated by numerically solving the complete two‐dimensional (2D) Navier–Stokes equation. [ABSTRACT FROM AUTHOR]