The role of grain boundaries in perovskite solar cells

With a certified power conversion efficiency (PCE) exceeding 22%, the hunt is now on clues to further improve the PCE and stability of perovskite (PVSK) solar cells toward commercialization. Polycrystalline PVSK films are grown by low temperature solution processes that results in the formation of sub-micron scale grains and consequent grain boundaries. The large discrepancy observed between optoelectronic properties of the polycrystalline films and single crystals of PVSK implies that grain boundaries may largely influence the optoelectronic properties of the PVSK thin film. In this article, important studies on the roles of the grain boundaries on optoelectronic properties and stability of the PVSK are reviewed.