Surfactant-assisted doctor-blading-printed FAPbBr₃ films for efficient semitransparent perovskite solar cells

Organic-inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion efficiencies. However, the majority of the reported devices have been fabricated via spin coating with a device area of < 1 cm². In this study, we fabricated a wide-bandgap formamidinium lead bromide (FAPbBr₃) film using a cost-effective, high-yielding doctor-blade-coating process. The effects of different surfactants, such as 1-α-phosphatidylcholine, polyoxyethylene sorbitan monooleate, sodium lauryl sulfonate, and hexadecyl trimethyl ammonium bromide, were studied during the printing process. Accompanying the optimization of the blading temperature, crystal sizes of over 10 µm and large-area perovskite films of 5 cm × 5 cm were obtained using this method. The printed FAPbBr₃ solar cells exhibited a short-circuit current density of 8.22 mA/cm², an open-circuit voltage of 1.175 V, and an efficiency of 7.29%. Subsequently, we replaced the gold with silver nanowires as the top electrode to prepare a semitransparent perovskite solar cell with an average transmittance (400-800 nm) of 25.42%, achieving a high-power efficiency of 5.11%. This study demonstrates efficient doctor-blading printing for preparing large-area FAPbBr₃ films that possess high potential for applications in building integrated photovoltaics.