Organic photovoltaics (OPV) now can exceed 20% power conversion efficiency in single junction solar cells. To close the remaining gap to competing technologies, both fill factor and open-circuit voltage must be optimized. The Langevin reduction factor is a well-known concept that measures the degree to which charge extraction is favored over charge recombination. It is therefore ideally suited as an optimization target in high-throughput workflows; however, its evaluation so far requires expert interaction. Here, an integrated high-throughput workflow is presented, able to obtain the Langevin reduction factor within a few seconds with high accuracy without human intervention and thus suited for autonomous experiments. This is achieved by combining evidence from UV-vis spectra, current-voltage curves, and a novel implementation of microsecond transient absorption kinetics allowing, for the first time, the intrinsic determination of charge absorption cross-sections, which is crucial to reporting stationary charge densities. The method is demonstrated by varying the donor:acceptor ratio of the high performance OPV blend PM6:Y12. The high reproducibility of the method allows to find a strictly exponential relationship between the PM6 exciton energy and the Langevin reduction factor.

Commercialization of perovskite photovoltaics hinges on the successful transition from laboratory-scale fabrication to industrial-scale manufacturing. A key challenge in fully printed perovskite solar cells with non-reflecting back electrodes is the deposition of high-quality, over-one-micron-thick perovskite layers to minimize photocurrent losses from incomplete light absorption. However, the formation of voids at the substrate/perovskite interface impedes the fabrication of such layers. Here, phase-field simulations reveal that the bottom voids originate from trapped residual solvents, driven by nanocrystal aggregation at the liquid-vapor interface during drying. Guided by these insights, we introduce a two-dimensional (2D) perovskite layer-assisted growth strategy to promote heterogeneous nucleation at the substrate, accelerating 3D perovskite crystallization and preventing solvent entrapment. This strategy enables the formation of highly crystalline, monolithic perovskite films exceeding one micrometer in thickness. The resulting void-free films maximize photocurrent extraction, achieving power conversion efficiencies of 19.9% on rigid substrates and 17.5% on flexible substrates in fully printed perovskite solar cells with non-reflecting carbon electrodes.

The outdoor stability of organic solar modules (OSMs) directly determines the success of the organic photovoltaic (OPV) technology, which is critically important but insufficiently studied so far.

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 Cs(0.05)FA(0.95)PbBr(3)-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 Cs(0.05)FA(0.95)PbBr(3) 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 x 5 cm(2) active area achieve a PCE of 5.8%, representing a crucial step towards the high-throughput, cost-effective production of perovskite solar modules.

Laser-induced forward transfer (LIFT) is presented as a new, contactless, and roll-to-roll compatible method for the deposition of silver top electrodes for organic solar cells (OSCs). Employing a nanosecond laser, highly reflective silver electrodes are printed by LIFT onto OSCs with P3HT:o-IDTBR bulk heterojunction layers. Upon optimization of ink composition, source film thickness, and laser parameters, the resulting organic solar cells reach efficiencies of more than 5%, which are similar to those of reference devices with vapor-deposited silver electrodes.

Recently, organic photovoltaics (OPV) have achieved power conversion efficiencies (PCE) above 20% thus coming closer to market entry. Building-integrated photovoltaics (BIPV) and building-attached photovoltaics (BAPV) are two key areas where the functional advantages of both OPV and BIPV/BAPV complement each other and thus could pave the way for market penetration of OPV. Herein, we report on large-area, all-solution-processed flexible OPV modules manufactured by a fully roll-to-roll (R2R) method with high levels of process repeatability. The OPV modules show an accelerated lifetime (ALT) of more than 1000 h and 2800 h under the ISOS-L2 and ISOS-D3 testing conditions, respectively. Long-term outdoor monitoring of the OPV modules was conducted in a typical central European climate, considering two distinct mounting angles that hold significant relevance for BIPV installations i.e., 45 degrees inclination with respect to the ground (representing the optimal tilt angle of the site) and 90 degrees vertical mounting (as mostly encountered in BIPV fa & ccedil;ades). The ISOS-O2 protocol was used as the test standard for outdoor monitoring. The results show that the OPV modules can offer higher daily specific energy yields (YFD), i.e., higher ratios of daily energy yield and STC WP capacity of the module, than a reference mono-crystalline (m-Si) module for BIPV installations typical of a rooftop case (i.e., 45 degrees), whereas for fa & ccedil;ade integrated cases (i.e., 90 degrees), OPV modules offer YFD values identical to that of m-Si modules. Detailed laboratory investigations reveal that the higher YFD values of the OPV modules at 45 degrees mounting stems from their negligible temperature coefficient of -0.008% degrees C-1, whereas at 90 degrees mounting, the angle-dependent response of the modules plays a crucial role.

Hermetic encapsulation is essential for organic electronic devices such as organic light-emitting diodes (OLEDs) and organic photovoltaic (OPV) devices, which are highly sensitive to degradation caused by water and oxygen. Building on our previous work [1], this study investigates a potentially cost-effective encapsulation method using the aerosol jet printing (AJP) process with Perhydropolysilazane (PHPS) as the encapsulating material. A key focus is understanding how line morphology evolves under varying printing conditions to optimize the final encapsulation layer. Specifically, we examine the influence of different process gas flow rates, printing speed and substrate temperature on the morphology of printed PHPS lines, with particular attention to the coffee-ring effect (CRE). The CRE is characterized by the ratio of the highest line edges to the minimum line thickness, referred to as the CRE index this work. Our findings demonstrate that a CRE index of less than 2 can be achieved through careful adjustment of gas flow parameters and printing speed at room temperature. However, the AJ-printed PHPS layer still exhibits a surface roughness approximately 10 times greater than that of a blade-coated sample, primarily due to CRE and line overlapping.

Photocurrent matching in conventional monolithic tandem solar cells is achieved by choosing semiconductors with complementary absorption spectra and by carefully adjusting the optical properties of the complete top and bottom stacks. However, for thin film photovoltaic technologies at the module level, another design variable significantly alleviates the task of photocurrent matching, namely the cell width, whose modification can be readily realized by the adjustment of the module layout. Herein, this concept is demonstrated at the experimental level for the first time for a 2T‐mechanically stacked perovskite (FAPbBr 3 )/organic (PM6:Y6:PCBM) tandem mini‐module, an unprecedented approach for these emergent photovoltaic technologies fabricated in an independent manner. An excellent I sc matching is achieved by tuning the cell widths of the perovskite and organic modules to 7.22 mm ( PCE PVKT‐mod = 6.69%) and 3.19 mm ( PCE OPV‐mod = 12.46%), respectively, leading to a champion efficiency of 14.94% for the tandem module interconnected in series with an aperture area of 20.25 cm 2 . Rather than demonstrating high efficiencies at the level of small lab cells, this successful experimental proof‐of‐concept at the module level proves to be particularly useful to couple devices with non‐complementary semiconductors, either in series or in parallel electrical connection, hence overcoming the limitations imposed by the monolithic structure.

Abstract The power conversion efficiency and long-term stability of organic solar cells have increased tremendously over the past years, reaching up to 19.2% on research cells and 14.5% on large modules. To take the final step towards industrialization, fabrication methods that can be upscaled and directly implemented in industrial processes need to be developed. In recent years, well-known industrial techniques, like drop-on-demand inkjet printing, have been further developed within the organic photovoltaics (OPV) community, as it enables versatile printing of arbitrary, free-form organic solar modules with different colors-a key feature for modern building-integrated photovoltaics and several niche applications of OPV printed on any kind object. In this review, aside a brief summary of recent developments, we provide an overview of the biggest challenges in OPV inkjet-printing and define design rules to overcome these issues. Further perspectives of OPV inkjet-printing conclude the review.

Organic solar cells (OSCs) are uniquely suited for semitransparent applications due to their adjustable absorption spectrum. However, most high-performance semitransparent cells reported to date are based on materials that have shown high power conversion efficiency for opaque devices. We therefore present a model to assess the optimum efficiency and transparency for a specific donor and acceptor band gap. The absorption characteristics of both donor and acceptor are modeled with spectral data of typical absorber materials from the literature which are adjusted to achieve the desired band gap value. The results show three distinct regions of high light utilization efficiency if the photopic curve is employed as a weighting function (corresponding to window applications), and a broad maximum for the plant action spectrum as a weighting function (corresponding to greenhouse applications). When comparing these findings to reported experimental values, it is evident that the band gaps of the materials used for the experimental studies do not correspond to the maxima identified by our simulation model. The analysis of the energy levels of molecules recorded in the literature confirms that all band gaps and therefore all LUE maxima are chemically feasible so that the performance of semitransparent OSCs can be further improved by designing materials with optimized absorption spectra.

Perovskite solar cells (PSC) are promising potential competitors to established photovoltaic technologies due to their superior efficiency and low-cost solution processability. However, the limited understanding of the crystallization behaviour hinders the technological transition from lab-scale cells to modules. In this work, advanced phase field (PF) simulations of solution-based film formation are used for the first time to obtain mechanistic and morphological information that is experimentally challenging to access. The well-known transition from a film with many pinholes, for a low evaporation rate, to a smooth film, for high evaporation rates, is recovered in simulation and experiment. The simulation results provide us with an unprecedented understanding of the crystallization process. They show that supersaturation and crystallization confinement effects determine the final morphology. The ratio of evaporation to crystallization rates turns out to be the key parameter driving the final morphology. Increasing this ratio is a robust design rule for obtaining high-quality films, which we expect to be valid independently of the material type.

Despite the great success of perovskite photovoltaics in terms of device efficiency and stability using laboratory-scale spin-coating methods, the demand for high-throughput and cost-effective solutions remains unresolved and rarely reported because of the complicated nature of perovskite crystallization. In this work, we propose a stable precursor ink design strategy to control the solvent volatilization and perovskite crystallization to enable the wide speed window printing (0.3 to 18.0 m/min) of phase-pure FAPbI3 perovskite solar cells (pero-SCs) in ambient atmosphere. The FAPbI3 perovskite precursor ink uses volatile acetonitrile (ACN) as the main solvent with DMF and DMSO as coordination additives is beneficial to improve the ink stability, inhibit the coffee rings, and the complicated intermediate FAPbI3 phases, delivering high-quality pin-hole free and phase-pure FAPbI3 perovskite films with large-scale uniformity. Ultimately, small-area FAPbI3 pero-SCs (0.062 cm2 ) and large-area modules (15.64 cm2 ) achieved remarkable efficiencies of 24.32 % and 21.90 %, respectively, whereas the PCE of the devices can be maintained at 23.76 % when the printing speed increases to 18.0 m/min. Specifically, the unencapsulated device exhibits superior operational stability with T90 >1350 h. This work represents a step towards the scalable, cost-effective manufacturing of perovskite photovoltaics with both high performance and high throughput.

The realization of scalable roll-to-roll production processes for metal-halide perovskite modules is a necessary development for transferring developments and technologies from the lab to the fab. Before that, it is imperative to close the efficiency gap not only between the devices fabricated on rigid substrates versus flexible substrates, but also between solar cells to solar modules. In this regard, a critical assessment of device architectures that are more compatible to scalable fabrication is needed. Obviously, the adaption to mass manufacturing must not negatively impact device performance and operational stability. Here, by investigating the properties of printed fullerene-based phosphonic acid dipole interface layers, we establish simplified self-assembled monolayer (SAM) based n-i-p architectures without any charge extraction layers other than SAMs, which are easily processed and are thus ideally suited for mass production. We show that a contact-layer design with a printed fullerene-based SAM that has phosphonic acid is sufficient to provide good charge selectivity and to minimize interface recombination at the bottom electrode. We further show that the same SAM molecule can be used as a p-type interface material on top of the perovskite. This simplified contact-layer design, which is based on one material for both hole and electron work-function adaption is successfully integrated into our fully printed module process comprising the deposition of a carbon top electrode. The achieved open-circuit voltage exceeds 1.1 V, and the fill factor surpasses 70%, highlighting the potential of this novel interface design concept for both rigid and flexible substrates. SAM enabled and simplified fully printed carbon-based flexible perovskite modules.

The pursuit of commercializing perovskite photovoltaics is driving the development of various scalable perovskite crystallization techniques. Among them, gas quenching is a promising crystallization approach for high-throughput deposition of perovskite films. However, the perovskite films prepared by gas-quenching assisted blade coating are susceptible to the formation of pinholes and frequently show inferior crystallinity if the interplay between film coating, film drying, and crystallization kinetics is not fully optimized. That arguably requires a thorough understanding of how single processing steps influence the crystallization kinetics of printed perovskite films. Here, in situ optical spectroscopies are integrated into a doctor-blading setup that allows to real-time monitor film formation during the gas-quenching process. It is found that the essential role of gas quenching treatment is in achieving a smooth and compact perovskite film by controlling the nucleation rate. Moreover, with the assistance of phase-field simulations, the role of excessive methylammonium iodide is revealed to increase grain size by accelerating the crystal growth rate. These results show a tailored control of crystal growth rate is critical to achieving optimal film quality, leading to fully printed solar cells with a champion power conversion efficiency of 19.50% and mini solar modules with 15.28% efficiency are achieved. Utilizing in situ monitoring techniques to optimize the crystallization kinetics of the perovskite films in the gas-quenching-assisted blade coating process, a champion power conversion efficiency of 19.50% for a fully printed carbon-electrode perovskite solar cell is achieved through the tailored control of crystal growth rates. image

Drop-on-demand inkjet printing is a promising and commercially relevant technology for producing organic electronic devices of arbitrary shape on a wide variety of different substrates. In this work we transfer the inkjet printing process of organic photovoltaic devices from 2D to 3D substrates, using a 5-axis robot system equipped with a multi nozzle inkjet printing unit. We present a ready-to-use 3D printing system for industrial application, using a 5-axis motion system controlled by commercial 3D motion software, combined with a commonly used multi-nozzle inkjet print head controlled by the corresponding printing software. The very first time inkjet-printed solar cells on glass/ITO with power conversion efficiencies (PCE) of up to 7% are realized on a 3D object with surfaces tilted by angles of up to 60{\deg} against the horizontal direction. Undesired ink flow during deposition of the inkjet-printed layers was avoided by proper ink formulation. In order to be able to print organic (opto-)electronic devices also on substrates without sputtered indium tin oxide bottom electrode, the bottom electrode was inkjet-printed from silver nanoparticle (AgNP) ink, resulting in the first all inkjet-printed (i.e., including bottom electrode) solar cell on a 3D object ever with a record PCE of 2.5%. This work paves the way for functionalizing even complex objects, such as cars, mobile phones, or Internet of Things (IoT) applications with inkjet-printed (opto-)electronic devices.

For the manufacturing of thin films of solution-processable organic semiconductors, e.g. for organic photovoltaics (OPV), meniscus guided-coating techniques are the method of choice for large-scale industrial applications. However, the process requires an in-depth understanding of the respective fluid dynamics to control the resulting film thickness. In this article, we derive an analytical expression to describe the layer thickness of coatings manufactured with a trapezoidal-shaped applicator as a function of various fluid and process parameters. The analytical calculations are compared with results from computational fluid dynamics (CFD) simulations and experimental data for an industrially relevant OPV active material system. The good agreement of all three approaches demonstrates the potential of the analytical and simulative methods to minimize the number of time- and resource-consuming experiments. Furthermore, our theoretical model can be used to enhance the homogeneity of large-area coatings by means of an acceleration profile of the applicator that can compensate for the liquid loss during the coating process. The respective analytical expression is validated by simulated and experimentally obtained data for long-distance coatings. Finally, this approach is used to fabricate a large-area OPV module with new world record efficiency.

Fully printed flexible perovskite solar cells (f-PSCs) show great potential for the commercialization of perovskite photovoltaics owing to their compatibility with high-throughput roll-to-roll (R2R) production. However, the challenge remains in the deficiency in controlling interfacial recombination losses of the functional layer, causing remarkable loss of power conversion efficiency (PCE) in industrial production. Here, a fullerene-substituted alkylphosphonic acid dipole layer is introduced between the R2R-printed tin oxide electron transport layer and the perovskite active layer to reduce the energetic barrier and to suppress surface recombination at the buried interface. The resulting f-PSCs exhibit a PCE of 17.0% with negligible hysteresis, retain 95% of their initial PCE over 3000 bending cycles and achieve a T95 lifetime of 1200 h under 1 sun and 65 degrees C in nitrogen atmosphere. Moreover, the fully printed flexible perovskite solar mini-modules (f-PSMs) with a 20.25 cm2 aperture area achieve a PCE of 11.6%. The encapsulated f-PSMs retain 90% of their initial PCE after 500 h damp-heat testing at 65 degrees C and 85% relative humidity (ISOS-D3). This work marks an important progress toward the realization of efficient and stable flexible perovskite photovoltaics for commercialization. Fully printed carbon-based flexible perovskite module with an efficiency of 11.6%.

Upscaling the coating of formamidinium lead triiodide (FAPbI(3)) thin film is essential to realizing full printing and thereby roll-to-roll production of perovskite photovoltaics. However, thin-film FAPbI(3) processed from antisolvent-free, printing methods suffer from undesirable degradation to the non-photoactive phase, particularly in ambient processing conditions. Here, the most critical stage in thin-film processing is identified as the gas-quenching treatment of the as-cast wet film. It is crucial to achieve both the nucleation of alpha-phase nanocrystals and their sufficient growth at room temperature, which are indispensable for templating the growth of a highly crystalline and stable alpha-FAPbI(3) film during subsequent thermal annealing. The gas-quenching-treated film without these alpha-phase nanocrystals can only be converted to meta-stable alpha-FAPbI(3) by thermal annealing. By precisely identifying the spontaneous doping of cesium ion (Cs+) as a key factor in triggering alpha-FAPbI(3) nucleation and the role of chloride ion (Cl-) in enhancing nanocrystal growth, a generalized mechanism for additive engineering for the precursor ink is theorized. The identified mechanism translates to a power conversion efficiency of 19.36% for fully printed carbon-electrode solar cells, 16.23% for carbon-electrode minimodules, and excellent operational stability, showing the promising potential of this proposed fabrication route in the upscaling of perovskite photovoltaics.

High-quality phase-pure formamidinium lead triiodide (FAPbI(3)) perovskite film needs to be fabricated under strict control of the surrounding atmosphere, which becomes more rigorous when large-area FAPbI(3) film is involved, leading to high-performance FAPbI(3) perovskite solar cells and modules predominantly carried out in an inert gas-filled atmosphere. In this work, we propose a scalable printing strategy for the large-area high-quality phase-pure FAPbI(3) film under a high-humidity atmosphere (up to 75% +/- 5% relative humidity) by regulating the perovskite precursor ink with a functional perfluoroalkylsulfonyl quaternary ammonium iodide. This approach decreases the energy barriers of cubic phase formation and heterogeneous nucleation, thereby regulating the FAPbI(3) crystallization. The printed photovoltaic small-area cells and large-area modules achieved remarkable power conversion efficiencies of 24.37% and 22.00%, respectively. Specifically, the unencapsulated device exhibits superior operational stability with T-90 > 1,060 h, ambient stability with T-90 > 2,020 h, and thermal stability with T-90 > 2,350 h.