2019/08/26 by Cho, Yeongsu, Berkelbach, Timothy C.
#Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.1908.09436
We present a many-body calculation of the band structure and optical spectrum of the layered hybrid organic-inorganic halide perovskites in the Ruddlesden-Popper phase with the general formula A'2An-1MnX3n+1, focusing specifically on the lead iodide family. We calculate the mean-field band structure with spin-orbit coupling, quasiparticle corrections within the GW approximation, and optical spectra using the Bethe-Salpeter equation. The model is parameterized by first-principles calculations and classical electrostatic screening, enabling an accurate but cost-effective study of large unit cells and corresponding thickness-dependent properties. A transition of the electronic and optical properties from quasi-two-dimensional behavior to three-dimensional behavior is shown for increasing n and the nonhydrogenic character of the excitonic Rydberg series is analyzed. The thickness-dependent 1s and 2s exciton energy levels are in good agreement with recently reported experiments and the 1s exciton binding energy is calculated to be 302 meV for n=1, 97 meV for n=5, and 37 meV for n=∞ (bulk MAPbI3).