Stabilization and Self-Passivation of Grain Boundaries in Halide Perovskite by Rigid Body Translation

The
physical properties of grain boundaries in halide perovskites,
especially their atomic structure, have not been fully understood
yet. We report that Σ5 [130] symmetrical tilt grain boundaries
can be stabilized by rigid body translation which is moving one side
of the grain parallel with respect to the adjacent grain. Such reconstruction
passivates grain boundaries by removing Pb–Pb and I–I
interactions that introduce shallow defect states in the band gap.
Rigid body translation also stabilizes the [110] antiphase boundary
as well in both CsPbI3 and CsPbBr3.