Photoelectrochemical and first-principles investigation on perylene dye-based perovskite/TiO2 photoelectrode

The halide perovskite/TiO 2 materials have been extensively employed for solar cells; however, they suffer from limited optoelectronic performance and stability in aqueous solution. In this manuscript, we employ a commercially available perylene dye, namely perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), between the halide perovskite layer and the TiO 2 layer, to improve the photoelectrochemical properties of the prototypical CH 3 NH 3 PbI 3 /TiO 2 film in the aqueous solution. The incorporation of the perylene dye into the perovskite photoanode induces a photocurrent value twice as much as that offered by the bare perovskite-based film in the aqueous solution. The first-principles calculations suggest that the adsorption of the perylene dye molecule on the halide perovskite substrate is stable and the dye/perovskite interfacial structure depends on the perovskite surface terminations: for the PbI 2 -terminated perovskite surface, the perylene dye molecule interacts with the perovskite surface via the O⋯Pb contact; for the CH 3 NH 3 I-terminated perovskite surface, the perylene dye molecule interacts with the perovskite surface via the H⋯N contact. This study facilitates the fundamental understanding of the dye-sensitized halide perovskite materials for optoelectronic applications.