Multilayer Blade-Coating Fabrication of Methylammonium-Free Perovskite Photovoltaic Modules with 66 cm2 Active Area
Solar cells based on hybrid organic/inorganic perovskites have shown an astonishing efficiency development in the past years, having peaked in power conversion efficiencies of >25% for small-area single-junction devices. To pave the way for future commercialization, however, high power conversion efficiencies also have to be demonstrated on areas multiple orders of magnitude larger. Herein, methylammonium-free perovskite photovoltaic modules with an active area of 66 cm2 are presented. All functional layers processable from solution are deposited by blade coating without the use of an antisolvent, demonstrating the feasibility of this approach for large-area module fabrication. The coating process is analyzed in detail and a model based on the Landau-Levich problem is developed for the blade-coating setup. The perovskite crystallinity can be improved by the addition of lead(II) thiocyanate, which results in increased crystallite size as judged by Williamson-Hall's analysis of X-ray diffraction data and corresponding scanning electron microscopy images. The homogeneity of the final modules is investigated with dark lock-in thermography and electroluminescence imaging, indicating only few shunts in the module area. Modules are made up of 15 serially interconnected solar cells and reveal a stabilized efficiency of 12.6% under maximum power point tracking.