Achieving Uniform Meniscus‐Assisted Coating Films by Modulating Three‐phase Contact Lines for Flexible Large‐area Organic Photovoltaic Modules

Abstract Coating uniform active layer films in a large area is important yet still challenging for the development of flexible organic photovoltaic (OPV). During meniscus‐assisted coating, parabolic‐shaped three‐phase contact lines generally form in the drying process, which causes nonuniformity of the films with streaks when enlarge the coating area. In this work, the shapes of the three‐phase lines are successfully modulated through a meniscus solution dwell (MSD) method, which led to film drying in a more synchronous speed along the coating direction and resulted in uniform film deposition. Based on D18:L8‐BO active layer coated with the MSD approach, a power conversion efficiency (PCE) of 18.21% is achieved for cells with a 0.04 cm 2 active area, and a PCE of 15.92% is obtained for modules with a 10.62 cm 2 active area on rigid glass substrates. Furthermore, the MSD method is further applied to flexible modules fabrication. The D18:L8‐BO module displayed a PCE of 14.48% with an active area of 34.88 cm 2 , and PM6:BTP‐eC9:PC 71 BM module displayed a PCE of 14.07% with an active area of 64.19 cm 2 .