Impact of Symmetry and Chain Length on the Excitonic, Electronic, and Optical Characteristics of Dion-Jacobson Phase Perovskites

Dion-Jacobson (DJ) phase halide perovskites have garnered significant attention for their excellent chemical stability, and charge transfer properties. As the ligand asymmetry increases, the band gap increases (PDA-DMPD-N-MPDA). The partial density of states indicates that the band gap contribution is related the [PbI6]4- octahedrons. The distribution of excitons is closely linked to near the CBM and the VBM. The excitonic properties reveal the maximum exciton binding energies (PDAPbI4-DMPDPbI4-N-MPDAPbI4, 0.048-0.259-0.273 eV), which are consistent with the changes in the organic ligand chain length. The absorption spectra shows that perovskites with asymmetric organic ligands exhibit better light absorption in the visible region.