Crystallization Enhancement and Ion Migration Suppression by a Multifunctional Additive for Stable Perovskite Solar Cells

Abstract

AbstractDue to defect‐assisted non‐radiative recombination and ion migration, the high defect density in the perovskite light‐absorbing layer severely limits the device's efficiency and stability. Here, pyrene‐4,5,9,10‐tetraone is introduced as an additive to the perovskite precursor. Pyrene‐4,5,9,10‐tetraone retards the crystallization of perovskite through coordination and hydrogen bonding, reducing the defect density and improving the crystal quality. Meanwhile, pyrene‐4,5,9,10‐tetraone distributed at the grain boundaries forms an energy well for free‐moving iodide ions, which doubles the activation energy of ion migration. Due to the improved crystal quality and defect passivation, the pyrene‐4,5,9,10‐tetraone‐based device demonstrates an efficiency of 25.90%. After 1000 h of damp heat test, the efficiency of the encapsulated device decays by 4.9%. It still maintains 92.4% of its initial efficiency after 2016 h aging under maximum power point tracking.