Effect of pressure on photocatalytic water splitting performance of Z-scheme RP/CH₃NH₃PbI₃ perovskite heterostructure

Energy is an extremely important strategic material basis for socio-economic development. Here, we have investigated the structural, electronic, optical, charge transfer and photocatalytic mechanism of red phosphorus RP/CH₃NH₃PbI₃ heterostructure under hydrostatic pressure by density functional theory (DFT) calculations. Ab initio molecular dynamics (AIMD) prove RP/CH₃NH₃PbI₃ is thermodynamically stable. Interestingly, direct band gap of RP/CH₃NH₃PbI₃ decreases linearly with increase of pressure. The band gap is 1.43 eV at 1.5 GPa, which can enhance the absorption of visible light and generate redshift in absorption edge. Interface charge redistribution makes valence/conduction band edge positions of RP monolayer and CH₃NH₃PbI₃ (010) surface vary with Fermi level, forming an internal electric field have ability to separate electron-hole pairs. Typical Z-scheme heterostructure is formed and supposed to have resulted strong redox ability. The theoretical results hope to provide a possibility for the future experimental preparation of CH₃NH₃PbI₃-based photocatalysts.