Environmentally friendly and roll-processed flexible organic solar cells based on PM6:Y6.

Organic Solar Cells (OSCs) have reached the highest efficiencies using lab-scale on active areas far below 0.1 cm^2. This tends to widen the so-called “lab-to-fab gap”, which is one of the most important challenges to make OSCs competitive. The most commonly used fabrication technique is spin-coating, which has poor compatibility with large-scale techniques and substantial material waste. Moreover, other techniques such as blade or slot-die coating are much more suitable for roll-to-roll manufacturing processes, which is one of the advantages the technology has compared, for example, to silicon solar cells. However, only a few studies report solar cells using these fabrication techniques. Additionally, for the environmentally friendly OSC scale-up, inks based on non-hazardous solvent systems are needed. In this work, slot-die coating has been chosen to coat the PM6:Y6 active layer, using o-xylene, a green solvent, without additives. The optimal coating parameters are defined through fine-tuning of the coating parameters, such as the drying temperature and solution concentration. Moreover, ternary devices with PCBM, and fully printed devices are also fabricated. Power conversion efficiencies of 6.26% and 7.16% are achieved for binary PM6:Y6 and ternary PM6:Y6:PCBM devices, respectively.

Environmentally friendly and roll-processed flexible organic solar cells based on PM6:Y6.

Organic Solar Cells (OSCs) have reached the highest efficiencies using lab-scale on active areas far below 0.1 cm^2. This tends to widen the so-called “lab-to-fab gap”, which is one of the most important challenges to make OSCs competitive. The most commonly used fabrication technique is spin-coating, which has poor compatibility with large-scale techniques and substantial material waste. Moreover, other techniques such as blade or slot-die coating are much more suitable for roll-to-roll manufacturing processes, which is one of the advantages the technology has compared, for example, to silicon solar cells. However, only a few studies report solar cells using these fabrication techniques. Additionally, for the environmentally friendly OSC scale-up, inks based on non-hazardous solvent systems are needed. In this work, slot-die coating has been chosen to coat the PM6:Y6 active layer, using o-xylene, a green solvent, without additives. The optimal coating parameters are defined through fine-tuning of the coating parameters, such as the drying temperature and solution concentration. Moreover, ternary devices with PCBM, and fully printed devices are also fabricated. Power conversion efficiencies of 6.26% and 7.16% are achieved for binary PM6:Y6 and ternary PM6:Y6:PCBM devices, respectively.

Environmentally friendly and roll-processed flexible organic solar cells based on PM6:Y6.

Organic Solar Cells (OSCs) have reached the highest efficiencies using lab-scale on active areas far below 0.1 cm2. This tends to widen the so-called “lab-to-fab gap”, which is one of the most important challenges to make OSCs competitive. The most commonly used fabrication technique is spin-coating, which has poor compatibility with large-scale techniques and substantial material waste. Moreover, other techniques such as blade or slot-die coating are much more suitable for roll-to-roll manufacturing processes, which is one of the advantages the technology has compared, for example, to silicon solar cells. However, only a few studies report solar cells using these fabrication techniques. Additionally, for the environmentally friendly OSC scale-up, inks based on non-hazardous solvent systems are needed. In this work, slot-die coating has been chosen to coat the PM6:Y6 active layer, using o-xylene, a green solvent, without additives. The optimal coating parameters are defined through fine-tuning of the coating parameters, such as the drying temperature and solution concentration. Moreover, ternary devices with PCBM, and fully printed devices are also fabricated. Power conversion efficiencies of 6.26% and 7.16% are achieved for binary PM6:Y6 and ternary PM6:Y6:PCBM devices, respectively.

Transmittance Control of a Water-Repellent-Coated Layer on a Tensioned Web in a Roll-to-Roll Slot-Die Coating System

Solar cells are important alternatives to fossil fuels for energy generation in today’s world, where the demand for alternative, renewable sources of energy is increasing. However, solar cells, which are installed outdoors, are susceptible to pollution by environmental factors. A solution to overcome this limitation involves coating solar cell surfaces with functional coatings. In this study, we propose a transmittance control method for a tensioned web in a roll-to-roll, transparent, water-repellent film coating. First, we analyzed the effects of process conditions on the transmittance and contact angle of the transparent water-repellent film during roll-to-roll slot-die coating. It was confirmed that the tension was the most dominant factor, followed by the coating gap. Through the tension control, the transmittance was changed by 3.27%, and the contact angle of the DI water was changed by 17.7°. In addition, it was confirmed that the transmittance was changed by 0.8% and the contact angle of DI water by 3.9° via the coating gap control. Based on these results, a transmittance prediction model was developed according to the tension and coating gap, and was then verified experimentally. Finally, a water-repellent film with a high transmittance of 89.77% was obtained using this model.

Investigation of edge formation during the coating process of Li-ion battery electrodes

In this manuscript, a method to reduce superelevations of lateral edges in cross-web direction during slot die coating of shear-thinning slurries for Li-ion battery electrodes (LIB) was developed. Therefore, the impact of the inner slot die geometry on the edge elevations was investigated. These elevations of the coating could be almost eliminated by optimizing the flow profile at the outlet of the slot die by modification of the internal geometry. This adaption is an essential step in optimizing the coating quality of slot die coating for battery electrodes to significantly reduce coating edges and, hence, the resulting production reject during the coating step of the industrial roll-to-roll process. It was also shown that lateral edges of the coating can be influenced explicitly by process parameters such as volume flow and gap between slot die and substrate. This correlation has already been shown for other shear-thinning material systems in previous works, which is now confirmed for this material system. At the beginning, the influence of different internal geometries on the formation of the edge elevations was shown. Finally, for the shear-thinning electrode slurry used in this work, optimal dimensions of the previously determined inner geometry for the slot die outlet were found. The optimization was performed for a state-of-the-art electrode area capacity (approximately 2.2 mAh cm−2). The results enable a significant reduction of defects and reject in the coating step of large-scale production of LIB electrodes in the future, adding to a more sustainable battery production.