Effect of Composition and Microstructure on the Mechanical Stability of Perovskite Solar Cells

We report on recent studies characterizing the intrinsic mechanical integrity of perovskite compositions and fully explore the role of various cation combinations, additives, and microstructure on perovskite cohesion. Adding cations to the perovskite decreased mechanical integrity, largely due to smaller grain sizes and increased concentration of PbI
₂
. Microindentation hardness testing was performed to estimate the fracture toughness of single-crystal perovskite, and the results indicated perovskites are inherently fragile, even in the absence of grain boundaries and defects. Introducing plastically deformable cations led to a modest improvement in cohesion, and the most robust architecture was observed by infusing perovskite into a porous TiO
₂
/ZrO
₂
/C layer that provided extrinsic reinforcement to mechanical and environmental stressors.