High-throughput screening of Ruddlesden–Popper perovskites with layer-dependent mechanical and thermal properties using DFT calculations

Abstract

Two-dimensional (2D) Ruddlesden–Popper perovskites have recently shown great promise in photovoltaics, thermoelectrics, catalysis and other energy applications owing to their diverse structures and intriguing properties. Employing the high-throughput calculations based on density functional theory, we establish a comprehensive database of Ruddlesden–Popper perovskites A_n+1B_nO_3n+1 (n = 1, 2, 3) including structural and mechanical stability, band gap and thermal conductivity. Compared with their bulk derivatives, 2D perovskites exhibit enhanced damage tolerance and crack resistance as well as decreased elastic moduli owing to the extra (AO) rock-salt layers. Meanwhile, 2D perovskites feature distinct lattice dynamics arising from the bonding character between neighboring (ABO₃)_n perovskite slabs. We decompose the thermal conductivities into in-plane and out-of-plane components and reveal remarkably reduced thermal conductivities along the out-of-plane direction. By means of phonon analysis, we assign the vibrational modes with strong anharmonicity and significant scattering to optical phonons originating from atomic motion constrained in rock-salt layers. The difference in mechanical and thermal properties is thus attributed to the counterbalance between rock-salt layers and perovskite slabs. This work provides fundamental insights into structural complexity and phonon transport in Ruddlesden–Popper perovskites and suggests practical guidelines to explore the class for emerging applications.