Air-processed 2D/3D perovskite solar cell achieve high-efficient and stable performance via graded interface engineering

Organic-inorganic hybrid perovskite solar cells (PSCs) has been rapid development due to the excellent photoelectric properties, but it also faces the issues of poor stability in high humidity environment. The introduction organic diammonium iodide could effectively passivate defect and improve stability in three-dimensional (3D) perovskite by forming Dion-Jacobson (DJ) phase two-dimensional (2D) perovskites. Here, a stable alternative, 4-(aminomethyl) piperidinium iodide (AMPI), is developed for high-performance 2D/3D PSCs. The DJ 2D perovskite layer which is grown in-situ on the 3D perovskite not only boosts the stability of PSCs due to its intrinsically stable structure and alternating hydrogen bonding interactions between the layers of organic and inorganic, but also modulates the energy levels aligned possibly between perovskite layer and spiro-OMeTAD HTL, thus facilitate the charge transfer and improves the open-circuit voltage (Voc). Finally, 20.11% power conversion efficiency (PCE) has been achieved of the 2D/3D PSCs. Furthermore, they exhibit batter stability in compassion of the control when they are stored in air conditions (25 °C and dark conditions) and 30–40% relative humidity for 700 h, which is owed to the moisture attacks protection from the layer of 2D perovskite to 3D perovskite films. This paper indicates the manufacture of high-performance and stable 2D-3D heterojunction PSCs used by nitrogenous heterocyclic compounds has a potential broad application prospect.