Scalable deposition of high-efficiency perovskite solar cells (PSCs) is vital to achieving commercialization. However, a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition, which adversely affects the efficiency and stability of PSCs. Now, researchers at China's Central South University, Hunan Institute of Engineering and Chinese Academy of Sciences (CAS) addressed this issue by incorporating 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) as the bridging layer between the tin oxide (SnO2) electron transport layer (ETL) and the perovskite film deposited via scalable two-step doctor blading.
The scientists reported that both experiment and simulation results demonstrated that MESK can passivate the trap states of Sn suspension bonds, thereby enhancing the charge extraction and transport of the SnO2 ETL.
Meanwhile, the strong interaction with uncoordinated Pb ions can modulate the crystal growth and crystallographic orientation of perovskite film and passivate buried defects.
Using MESK interface bridging, PSCs fabricated via scalable doctor blading in ambient condition achieved a power conversion efficiency (PCE) of 24.67%, which is one of the highest PCEs for doctor-bladed PSCs, and PSC modules with an active area of 11.35 cm2 achieve a PCE of 19.45%.
Furthermore, PSCs exhibit excellent long-term stability, and the unpackaged target device with a storage of 1680 h in ambient condition (25 °C and humidity of 30% relative humidity (RH)) can maintain more than 90% of the initial PCE.
The research provides a strategy for constructing a high-performance interface bridge between SnO2 ETL and perovskite film, and achieving efficient and stable large-area PSCs and modules fabricated via scalable doctor-blading process in ambient condition.