Density functional theory prediction of a novel hybrid organic–inorganic bidentate perovskite with charge transport perpendicular to the inorganic layer

Abstract

Bidentate perovskites, a novel family within this class of solids, have recently attracted the attention of the scientific community. Their spacers feature a dual anchoring mechanism onto the inorganic framework, characteristic of the Dion-Jacobson phases, while the attachment occurs within the same octahedral layer, as observed in the Ruddlesden–Popper perovskites. In this work, we present a hybrid organic–inorganic bidentate perovskite that exhibits diamines as organic spacers between the inorganic layers of PbI₆ octahedra, in particular, 4,4′-dithiodianiline. A geometric optimization was carried out within the Density Functional Theory framework as implemented in the Quantum Espresso code. We employed the nonempirical consistent-exchange vdW-DF-cx functional [DOI:10.1103/PhysRevB.51.4014] to obtain precise geometry and electronic properties. The total density of states, band structure, valence and conduction band, and changes in the electronic clouds are analysed, finding that the band gap of this new perovskite is 2.55 eV, which reveals a semiconductor nature. In the valence band, the dominant contribution originates from the inorganic layer, whereas in the conduction band the initial contributions arise from the spacer, in particular, from the carbon and sulfur atoms. This suggests charge transport between the inorganic layers, perpendicularly and through the organic moieties. Our findings therefore contribute to the development of novel materials for optoelectronic applications, such as solar cells.