Faculty Sponsor's Department(s):
Three-dimensional (3D) inorganic-organic hybrid perovskites exhibit interesting optoelectronic properties that make them excellent candidates for energy-related applications, but their utility is limited by their poor chemical and environmental stability. In contrast, two-dimensional Ruddlesden-Popper (2DRP) phase perovskites have shown promising stability; however, insulating organic cations interleave the inorganic perovskite layers, which inhibits electrical conductivity across layers. Reducing the interlayer distance has the potential to address this issue, as quantum confinement effects may become less dominant, which would improve charge transport. In this study, the electronic structure of 2DRP hybrid lead iodide perovskites with short interlayer distances was characterized through density functional theory (DFT) calculations and compared against 2DRP hybrid lead iodide perovskites with longer interlayer distances. Band structure calculations showed that the short interlayer compounds generally had a slightly larger band gap. Incorporating spin-orbit coupling decreased the band gap and slightly changed the curvature of the band structure. Crystal orbital Hamiltonian population (COHP) analysis showed that the states at the top of the valence band and bottom of the conduction band are comprised of anti-bonding interactions between lead and iodine.