“Our study introduces an innovative lead iodide (PbI2) secondary growth and π-π stack regulation strategy that enhances the photovoltaic efficiency and stability of perovskite solar cells ...

A 100mm petri dish containing water is placed on an overhead projector. When solid Pb(NO 3) 2 is place on one side and solid KI on the other, PbI2 precipitates in the center.

Scoop a small amount of KI into the water directly opposite the Pb(NO3)2 A precipitate of PbI2 will form near the center of the dish.