Fluid Mechanics Inspired Sequential Blade-Coating for High-Performance Large-Area Organic Solar Modules

Despite rapid advances in the field of organic solar cells (OSCs), high-performance large-scale OSC modules are limited. In this study, it is found that the non-Newtonian fluid feature of conjugated polymer primarily causes the wedge-shaped mass (donor and/or acceptor component)/phase distribution of blends in large-scale blade coating, which results in the lower module efficiency. To address the critical issue in printing manufacturing, a reversible and sequential layer-by-layer (RS-LBL) deposition method with sequential twice forward/reverse blade-coating of polymer donor and forward blade-coating of Y6 acceptor, is developed for precisely controlling fluid mechanics of PM6:Y6 active layer. Through using the RS-LBL strategy, uniform morphology and favorable phase separation and crystallization are obtained in the 10 x 10 cm(2) active layer. As a result, the RS-LBL-based OSCs show excellent operational stability, and an outstanding PCE of 13.47% is achieved with significantly suppressed charge recombination losses in the 36 cm(2) large-area OSC module, which represents the highest efficiency of binary solar modules with the area over 30 cm(2). This study provides a feasible route for the next generation of high-performance large-area OSCs and OSC modules.