Intermediates transformation for efficient perovskite solar cells

Perovskite materials have made a great progress in terms of the power conversion efficiency (PCE), rising from 3.8% to 25.2%. To obtain pinhole-free, superior crystal, and high-quality perovskite films with less defect, intermediates transformation is important, which has been clearly studied and widely applied. In this review, we systematically summarize the commonly formed intermediates and detailedly analyze their mechanisms from five aspects: (1) Solvent-induced intermediate; (2) HI-induced intermediate; (3) CH3NH2-induced intermediate; (4) MAAc-induced intermediate; (5) other intermediates. Finally, we also provide some prospects on high-quality perovskite fabrication based on using intermediates prudently.