The performance and scalability of perovskite solar cells (PSCs) is highly dependent on the morphology and charge selectivity of the electron transport layer (ETL). This work demonstrates a high-speed (1800 mm min⁻¹), room-temperature (25 °C–30 °C) deposition of large-area (62.5 cm²) tin oxide films using a multi-pass spray deposition technique. The spray-deposited SnO₂ (spray-SnO₂) films exhibit a controllable thickness, a unique granulate morphology and high transmittance (≈85% at 550 nm). The performance of the PSC based on spray-SnO₂ ETL and formamidinium lead iodide (FAPbI₃)-based perovskite is highly consistent and reproducible, achieving a maximum efficiency of ≈20.1% at an active area (A) of 0.096 cm². Characterization results reveal that the efficiency improvement originates from the granular morphology of spray-SnO₂ and high conversion rate of PbI₂ in the perovskite. More importantly, spray-SnO₂ films are highly scalable and able to reduce the efficiency roll-off that comes with the increase in contact-area between SnO₂ and perovskite film. Based on the spray-SnO₂ ETL, large-area PSC (A = 1.0 cm²) achieves an efficiency of ≈18.9%. Furthermore, spray-SnO₂ ETL based PSCs also exhibit higher storage stability compared to the spin-SnO₂ based PSCs.

https://onlinelibrary.wiley.com/doi/abs/10.1002/smtd.202101127