Predictive Modeling of Cracks within Flexible Perovskite Thin Films

Cracking behaviors within perovskite thin films were modeled through finite element analysis. Coupons of polyethylene terephthalate or PET, Indium Tin Oxide or ITO, and perovskite layers were placed in a three-point bend set-up and deformed. Modeling gave insight into ranges for physical properties of each layer, when absent or greatly varied in literature. The model proved the relationship between perovskite crystal size and its mechanical tolerance. Models with smaller crystals withstood more than 30% further displacement than those with crystals twice its size. A material replacement of ITO, the driving force causing cracking in films, was also modeled and cracking within the perovskite layer occurred significantly later, showing an improved resilience to bending.