Stabilizing the Ag Electrode and Reducing J-V Hysteresis through Suppression of Iodide Migration in Perovskite Solar Cells

Hysteresis and stability issues in perovskite solar cell (PSCs) hinder their commercialization. Here, we report an effective and reproducible approach for enhancing the stability of and suppressing the hysteresis in PSCs by incorporating a small quantity of two-dimensional (2D) PEA2PbI4 [PEA = C6H5(CH2)2NH3] in three-dimensional (3D) MAPbI3 [MA = CH3NH3 ] [denoted as (PEA2PbI4)x(MAPbI3)], where the perovskite films were fabricated by the Lewis acid–base adduct method. A nanolaminate structure comprising layered MAPbI3 nanobricks was created in the presence of 2D PEA2PbI4. For x = 0.017, a power conversion efficiency (PCE) of as high as 19.8% was achieved, which was comparable to the 20.0% PCE of a MAPbI3-based cell. Density functional theory (DFT) calculations confirmed that iodide migration was suppressed in the presence of the 2D perovskite as a result of a higher activation energy, which was responsible for the significant reduction in hysteresis and the improved chemical stability against a Ag electro...