Zahrah Almutawah1 Ramez Hosseinian Ahangharnejhad1 Zhaoning Song1 Adam Phillips1 Yanfa Yan1 Michael Heben1

1, University of Toledo, Toledo, Ohio, United States

Organic-inorganic metal halide perovskites have attracted much interest and shown great promise in recent years due to their compatibility with cheap solution processing, ease of fabrication, and enhanced power conversion efficiencies. Currently, perovskite solar cells are transitioning from small area devices to large area devices that are compatible with manufacturing. Blade-coating is a promising deposition technique because it is a low cost, environmentally friendly, and easily translated to roll-to-roll processing. Most current work has focused on fabricating high efficiency perovskite solar cells using the single step-based blade coating. However, the most recent 23.3% record efficiency device was fabricated using the two-step spin-coating method. In this study, we investigate the possibility of fabricating large area perovskite solar cells by sequentially depositing PbI2 and mixed organic iodides consisting of FAI and MABr (where FA is formamidinium, and MA is methylammonium) using the blade coating technique. The blade-coated bi-layer precursor films are annealed under different conditions to examine conversion to the perovskite phases. This study will focus on understanding the formation and growth behaviors of perovskites formed in a two-step blade-coating process when the pre-deposited PbI2 films are reacted with organic iodide solution with various concentrations of mixed FA/MA cations. Comprehensive understating of the nucleation and growth behavior of perovskites during the intercalation process will provide insights to improve control of the film quality and allow device performance for devices beyond the simple MAPbI3 system to be improved.