Importance of Spin-Orbit Coupling in Hybrid Organic/Inorganic Perovskites for Photovoltaic Applications

Three-dimensional (3D) hybrid perovskites CH3NH3PbX3 (X = Br, I), have recently been suggested as new materials for dye sensitized solar Cells (DSSC) leading to a new class of hybrid semiconductor photovoltaic cells (HSPC). Thanks to density functional theory calculations, we show that the band. gap Of these compounds is dominated by a giant spin-orbit coupling (SOC) in the conduction-band(CB). At room temperature, direct and isotropic optical transitions are associated to a spin orbit split-off band related to the triply degenerated CB of the cubic. lattice without SOC. Due to the strong SOC, the electronic states involved in the optical absorption are only :slightly Perturbed by,local distortions of the lattice. In addition, band, offset calculations confirm that CH3NH3PbX3/TiO2 is a reference material for, driving electrons toward the electrode in HSPC Two dimensional (2D), hybrids are also suggested to reach,further.,flexibility for light Conversion efficiericy. Our study affords the bask concepts to reach the level of knowledge already attained. for optoelectronic properties of conventional semiconductors.