Structures and Electronic Properties of Different CH3NH3PbI3/TiO2 Interface: A First-Principles Study

Methylammonium lead iodide perovskite, CH3NH3PbI3, has attracted particular attention due to its fast increase in efficiency in dye sensitization TiO2 solid-state solar cells. We performed first-principles calculations to investigate several different types of CH3NH3PbI3/TiO2 interfaces. The interfacial structures between the different terminated CH3NH3PbI3 and phase TiO2 are thoroughly explored, and the calculated results suggest that the interfacial Pb atoms play important roles in the structure stability and electronic properties. A charge transfer from Pb atoms to the O atoms of TiO2 lead to the band edge alignment of Pb-p above Ti-d about 0.4 eV, suggesting a better carries separation. On the other hand, for TiO2, rutile (001) is the better candidate due to the better lattice and atoms arrangement match with CH3NH3PbI3.