Batch chemical bath deposition of large-area SnO2 film with mercaptosuccinic acid decoration for homogenized and efficient perovskite solar cells

Chemical bath deposited tin oxide film (CBD SnO2) has been demonstrated as an amazing electron transporting layer for high photoconversion efficiency (PCE) hybrid perovskite solar cells (PSCs) over 25 %. The current CBD process is normally studied for small area devices. A rapid batch production of large-area CBD SnO2 film with high and uniform performance is essential for potential upscaling of perovskite solar module. Herein, we carried out a modified batch CBD process, a double chemical bath deposition (DC), for batch fabrication of large-area (400 cm2) SnO2 films and realized a homogenized PCE with a variance (Va) of 0.127, comparing to that of control sample of Va at 2.833. We further introduced mercaptosuccinic acid (MSA) at the interface of SnO2/perovskite for convenient energy band alignment and defects passivation, which significantly improved the PCE, stability and homogeneity of the devices. As a result, the mix-cation planar PSCs reaches 21.24% with further reduced Va of 0.073. A high efficiency of 22.54% was obtained for the narrow band gap FA-based perovskite device. These results suggest high potential of this modified CBD route for large area and high efficiency perovskite module preparation.