“…Among these various approaches to improve device efficiency and stability, new charge‐transport materials have been demonstrated to be an effective approach . A series of efficient charge‐transport layers have been developed to satisfy the demands, including alkali salts, zwitterionic molecules, ionic liquids, n‐type metal oxides such as TiO x , ZnO, SnO x , Al‐doped ZnO, and Mg‐doped ZnO, neutral polymers (e.g., PEIE), and conjugated polyelectrolytes (e.g., PFN) . Among them, metal oxides are an important class of electron‐transport materials for inverted PSCs (i‐PSCs), and have attracted significant attention.…”