Figure 5: Propagation channels.
From: Ionic polarization-induced current–voltage hysteresis in CH3NH3PbX3 perovskite solar cells
Periodic crystalline (defect free) MAPbI3 sample. Cyan and brown spheres represent I and Pb ions, respectively. MA is shown as sticks. Periodic boundary conditions are applied in all the crystallographic directions. Black arrows point to equatorial and axial I− ions. Red and green arrows indicate the axial and equatorial channels for MA+ and Pb2+ ion migration.
