In-Situ Repair Strategies for Defects in Perovskite Solar Cells.

Perovskite solar cells have achieved significant progress in recent years. However, they still have challenges in photovoltaic conversion efficiency and long-term stability. Widespread defects in perovskite films are one of the most important factors leading to their poor performance. Defect passivation has become the most common strategy for film quality optimization. However, these methods are essentially just deactivation treatments of the defective sites that have already formed and might leave behind influential legacy components, rather than repairing defective crystalline domains timely when film formation begins. Recent high-profile in-situ repair strategies can execute these functions simultaneously, with the concept emphasizing repair of defective regions into perovskite crystals in-situ during crystallization, as well as mechanical self-healing at the film scale. Here, common coping strategies for perovskite defects are comparatively discussed in terms of the nature of perovskite defects, and several insights on uniquely advantageous in-situ repair of perovskite films are highlighted, followed by a focused analysis of their mechanisms of action during preparation and practical operation. This concept provides guidance for developing more effective and sustainable defect repair strategies with specific potential to improve perovskite film quality and device performance.