Influences of Inorganic Sublattice Stacking on Out-of-Plane Charge Transport in Two-Dimensional Ruddlesden–Popper Perovskites: A First-Principles Study

Two-dimensional (2D) Ruddlesden–Popper perovskites (RPPs), which possess a strong quantum confinement effect, have been demonstrated to exhibit out-of-plane charge transport, but the factors that determine the interlayer charge transport in 2D RPPs are far from being explored. In this study, using a recently developed ab initio simulation method which combines density functional theory calculations, semiclassical Marcus theory, and Einstein relationship, we systematically investigate the out-of-plane charge mobilities by focusing on the 2D RPPs with different organic spacers and stacking patterns of the inorganic sublattice. It is found that regardless of the organic species, the arrangement of neighboring inorganic layers can significantly manipulate the reorganization energies when the charge carriers are spatially localized in the inorganic flakes, while the electronic couplings between inorganic layers are weakly affected in 2D RPPs. Resultantly, the out-of-plane charge mobilities are enhanced 1–2 orders of magnitude when the inorganic sublattice displays the configuration with adjacent inorganic sheets showing up-to-down alignment in the 2D RPPs. These findings provide novel insights toward designing 2D RPPs with boosted out-of-plane charge transport when carrier localization occurs in the inorganic sheets of the 2D RPPs.