First-principles calculation study of electronic structures and magnetic properties of Mn-doped perovskite crystals for solar cell applications

Abstract

The electronic structures and magnetic properties of manganese (Mn)-doped formamidinium lead halide perovskite compounds (FAPbI3, where FA = NH2CHNH2+) were investigated for solar cell application. The effects of Mn doping into FAPbI3 crystals on electronic structures, chemical shifts in nuclear magnetic resonance, and optical absorption spectra were studied by first-principles calculation on the basis of the density functional theory. The electron density distribution of the 6p orbital was delocalized on an iodine atom at the highest occupied molecular orbital, and that of the 3d orbital was localized on a Mn atom at the lowest unoccupied molecular orbital. The absorption properties in the near-infrared region originated from the first excitation process of ligand-metal charge transfer (LMCT). The chemical shifts of I-NMR and the g-tensor of Mn ions were associated with nuclear quadrupole interactions based on an electron field gradient and asymmetry parameters. The combination of LMCT with magnetic interactions is important for developing photovoltaic solar cells with a broad-band optical absorption spectrum in the near-infrared region.