Flexography

Abstract: The printing of large-area organic solar cells (OSCs) has become a frontier for organic electronics and is also regarded as a critical step in their industrial applications. With the rapid progress in the field of OSCs, the highest power conversion efficiency (PCE) for small-area devices is approaching 15%, whereas the PCE for large-area devices has also surpassed 10% in a single cell with an area of ≈1 cm2 . Here, the progress of this fast developing area is reviewed, mainly focusing on: 1) material requirements (materials that are able to form efficient thick active layer films for large-area printing); 2) modular designs (effective designs that can suppress electrical, geometric, optical, and additional losses, leading to a reduction in the PCE of the devices, as a consequence of substrate area expansion); and 3) printing methods (various scalable fabrication techniques that are employed for large-area fabrication, including knife coating, slot-die coating, screen printing, inkjet printing, gravure printing, flexographic printing, pad printing, and brush coating). By combining thick-film material systems with efficient modular designs exhibiting low-efficiency losses and employing the right printing methods, the fabrication of large-area OSCs will be successfully realized in the near future.

Abstract: Inline printing and coating methods have been demonstrated to enable a high technical yield of fully roll-to-roll processed polymer tandem solar cell modules. We demonstrate generality by employing different material sets and also describe how the ink systems must be carefully co-developed in order to reach the ambitious objective of a fully printed and coated 14-layer flexible tandem solar cell stack. The roll-to-roll methodologies involved are flexographic printing, rotary screen printing, slot-die coating, X-ray scattering, electrical testing and UV-lamination. Their combination enables the manufacture of completely functional devices in exceptionally high yields. Critical to the ink and process development is a carefully chosen technology transfer to industry method where first a roll coater is employed enabling contactless stack build up, followed by a small roll-to-roll coater fitted to an X-ray machine enabling in situ studies of wet ink deposition and drying mechanisms, ultimately elucidating how a robust inline processed recombination layer is key to a high technical yield. Finally, the transfer to full roll-to-roll processing is demonstrated.

Abstract: Process for preparing flexographic photopolymer elements by passing into the nip of a calender a photopolymer composition mass comprising elastomeric binder, monomeric compound, and photoinitiator and calendering the photopolymer composition either between (1) a support and multilayer cover element consisting essentially of a flexible cover film, optionally a flexible polymeric film, e.g., polyamide, and a layer of elastomeric composition which is photosensitive or becomes photosensitive during or after calendering, or between (2) two supports, one of which is removed prior to contact, e.g., by lamination or pressing, with the multilayer cover element. The flexographic photopolymer elements are useful for flexographic printing, e.g., dry-offset, letterpress printing.

Abstract: A photosensitive printing element having an IR ablatable layer and at least one barrier layer as set forth within and a process for making a flexographic printing plate from such an element are disclosed.