Single-Solution Bar-Coated Halide Perovskite Films via Mediating Crystallization for Scalable Solar Cell Fabrication

The development of a scalable fabrication technology for halide perovskite solar cells (HPSCs) is an important challenge to realize their commercialization. In particular, continuous solution-coating processes are needed to produce scalable large-area HPSCs. Herein, we report a single-solution bar-coating process that introduces an intermediate phase stage for large-area CH₃NH₃PbI₃ films with full coverage and smooth morphology using N-cyclohexyl-2-pyrrolidone (CHP) as a mediator. In contrast to the conventional double-solution coating methods that use antisolvent treatments, the preformed uniform intermediate phase in the single-solution bar-coating process enables the formation of highly uniform perovskite films with a 10 cm × 10 cm area even without antisolvent treatment. The HPSCs fabricated using the resultant single-solution bar-coated perovskite films exhibit superior photovoltaic performance, narrower distribution, and smaller loss with a larger active area than devices fabricated using single-solution spin-coated perovskite films.