Toward All-Vacuum-Processable Perovskite Solar Cells with High Efficiency, Stability, and Scalability Enabled by Fluorinated Spiro-OMeTAD through Thermal Evaporation

Abstract

Developing scalable technologies in perovskite solar cells (PSCs), including the deposition of uniform perovskite photoactive layers and charge transport layers, is critical for successfully migrating the recently developed advances in the PSC community toward industrialization. Herein, efficient and stable large-area PSCs using vacuum-deposited fluorinated analogue Spiro-OMeTAD (Spiro-mF) and methylammonium lead iodide (MAPbI(3)) as hole transport and absorber layers, respectively, are demonstrated. The vacuum-deposited Spiro-mF exhibits improved crystallinity compared with the solution-processed counterpart through the enhanced molecular orientation along the pi-pi stacking direction, promoting the charge transport characteristics. Also, its uniform surface morphology contributes to the better quality crystallinity of the overlying perovskite film, which altogether leads to improved device performance and operational stability. Moreover, the all-vacuum deposition process allows the fabrication of large-area (250 mm(2)) and scalable (75 x 75 mm(2)) PSCs with excellent reliability in device performance.