Abstract
Grain boundaries (GBs) in polycrystalline halide perovskite solar cells play a significant role in not only device performance but also stability. The first section of this chapter (Section
) provides fundamental aspects of grain boundaries. In the following section (Section
), both positive and negative roles of GBs in the device performance of organic‐inorganic halide perovskite (OIHP) solar cells are discussed along with various engineering approaches that tune the GB properties. In Section
, enhanced ion transport through GBs is depicted that causes the
I–V
hysteresis in OIHP solar cells. Finally, in Section
, moisture penetration along the GBs is illustrated that ultimately degrade the entire structure and deteriorate the perovskite solar cell stability.