Ultralow Thermal Conductivity of 2D Dion–Jacobson (PDA)(FA)n−1PbnI3n+1 Perovskite Films

Two-dimensional (2D) perovskites exhibit enhanced thermal stability compared to three-dimensional perovskites, especially the emerging 2D Dion-Jacobson (DJ) phase perovskite. However, the heat transfer mechanisms in DJ phase perovskites are rarely reported. Herein, we determine thermal conductivities of (PDA)(FA)n