Fiber-bridging-induced toughening of perovskite for resistance to crack propagation

Perovskite solar cells (PSCs) emerged as a promising photovoltaic technology because of the great progress in power conversion efficiency (PCE). However, their intrinsic chemical instability and the unrevealed reliability limit their deployment in commercialization. In particular, the reliability of solar panels, associated with strength against external forces such as hailstones or wind load, is a critical assessment to ensure constant operation in the lifespan of the warranty. However, the mechanical properties connecting impact resistance are rarely reported for perovskite photovoltaics. In this work, we emphasize the mechanical properties improvement by incorporating a natural one-dimensional material, ethyl cellulose (EC), within the perovskite films, working as the fiber-bridging component to increase the toughness of the intrinsically brittle perovskite crystals. As a result, the EC-incorporated perovskite layer exhibited much-improved mechanical properties, with Young's modulus 3 times higher than that of pristine film, and showed robust stability under various harsh conditions.