Crosslinking‐Driven Chemical Homogeneity Enhances Performance of Pre‐Seeded Perovskite Solar Cells

Abstract Perovskite solar cells (PSCs) have achieved impressive efficiency, but their commercialization is limited by issues like chemical homogeneity within the perovskite films, leading to defects and phase segregation, which severely compromise the stability and performance of PSCs. This study presents a novel approach to overcoming these barriers by employing N,N ‐methylenebisacrylamide (MBA) as a multifunctional crosslinking agent within the perovskite structure. MBA enhances chemical uniformity both laterally and vertically, improves crystallinity, and boosts overall film stability by forming a robust crosslinked network that regulates nucleation and growth dynamics during the pre‐seeding process. This modification ensures a uniform distribution within the perovskite matrix and significantly reduces defect densities. As a result, MBA‐treated PSCs achieved a notable improvement in power conversion efficiency (PCE), reaching up to 24.26%, compared to 22.64% in control devices. Additionally, the MBA‐modified devices demonstrated remarkable stability, maintaining 90% of their initial efficiency after 1200 h of continuous illumination, in contrast to the 50% efficiency loss observed in control devices after just 500 h. These findings underscore the transformative potential of MBA as an additive in PSCs, offering a viable pathway to not only enhance efficiency but also significantly improve the long‐term stability of these devices, thus bringing PSCs closer to commercial viability.