Precise Meniscus Control for Printing Efficient Organic Photovoltaics by Flexible Microcomb Printing

ABSTRACT Meniscus guided printing (MGP) is a promising technique for fabricating a large area active layer of organic photovoltaic cells (OPVs). The flexible microcomb printing (FMCP) is a particular type of MGP that offers high shear rates and relaxed requirements on the gap control. However, printing large film with good thickness uniformity remains a challenge for FMCP. This work systematically studies the hydrodynamics of the film formation and deposition process by FMCP, and provides two optimization ideas: the flow rate automatically regulated by the back pressure, and the internal chamfer that stabilizes the contact line. Combined with the evaporation convection mechanism, the effects of different parameters on the morphology of the film are studied, and the hydrodynamic causes of the formation of stripes in the process of evaporation deposition are clarified. The power conversion efficiency (PCE) of the bulk heterostructure of the donor/acceptor device made by FMCP is 16.72%, and the PCE of the layer‐by‐layer printed device by FMCP is further improved to 16.93%. This work shows that the improved FMCP is an efficient, robust, and scalable film printing technology.