Effect of pressure on the structure transitions and electronic properties of the organic semiconducting Bis(salicylaldehyde) crystal

Abstract

The structure, electronic, and optical properties of bis(salicylaldehyde) crystal under 0–300 GPa pressure are calculated by density functional theory (DFT). By comparing the lattice parameters (i.e., lattice constants, bond lengths, and bond angles) under different pressures, it is found that the lattice parameters are sensitive to pressure and change complicatedly with pressure. Furthermore, the analysis of the electronic structure shows that the crystal is an indirect bandgap semiconductor at 0 GPa and becomes a conductor at 115, 155, and 185 GPa, respectively, where the far- and near-Fermi levels density of states (DOS) in the valence band are mainly contributed by the O-2s orbital electrons, the joint effect of the C-2p and the O-2p orbital electrons respectively. Dielectric function studies have shown that it exhibits novel optical properties as the pressure increases, leading to different photoelectric properties.