Seed-assisted growth for high-performance perovskite solar cells: A review

The rapid increase in the power conversion efficiency (PCE) of perovskite solar cells (PSCs) is closely related to the development of deposition techinique for perovskite layer. The high-quality perovskite film enables efficient charge transportation and less trap states, which are eventually translated into enhanced device performance. Seed-assisted growth (SAG) is a potential technique for depositing highly-crystallized perovskite films with preferential crystal orientation among the numerous approaches related to crystallization modulation. In this review, we summarize the recent advances in the SAG technique for both one-step and two-step processed perovskite films. Additionally, seeding at the buried interface and on the top surface are also introduced. We present different seeds and their corresponding seeding mechanism in detail, such as inorganic nanomaterials, organic ammoniums, alkali metal halides, and perovskite seeds. Finally, challenges and perspectives are proposed to investigate the potential expansion of seeding engineering in high-performance PSCs, particularly large-area devices.