Spin-Orbit Coupling Accelerates the Photoinduced Interfacial Electron Transfer in a Fullerene-Based Perovskite...

In this work, we explore the interfacial properties of the C₆₀-Py@MAPbI₃ heterojunction of the PbI-terminated MAPbI₃(001) surface and pyridine-functionalized C₆₀-Py fullerene derivative through both collinear and noncollinear density functional theory calculations with and without spin-orbit coupling (SOC) effects. C₆₀-Py is bound to the MAPbI₃ surface through interfacial Pb-O and Pb-N bonds. Although C₆₀-Py@MAPbI₃ is predicted to be the same type II heterojunction at all of the computational levels considered, the SOC effects largely decrease the energy gap of the first conduction bands of C₆₀-Py and MAPbI₃, thereby accelerating the interfacial electron transfer. Further dynamics simulations show that the inclusion of the SOC effects induces the transfer of approximately 80% of electrons from MAPbI₃ to C₆₀-Py within 1 ps. The work demonstrates that the SOC effects are indispensable for the interfacial properties of C₆₀-Py@MAPbI₃ and could also play a non-negligible role in tuning the optoelectronic properties of fullerene-based or similar perovskite devices.