Abstract

Metal halide perovskites (MHPs) have tremendous promise as a low- cost, highly efficient photovoltaic technology; however, their potential is limited by the lack of stability. We have identified MHPs as the most mechanically fragile of any PV technology. In fact, the elastic properties, bonding, and fracture energy of MHPs are essentially comparable to salts such as NaCl. In this work, we demonstrate how starch-based polymer additives can be used to significantly improve the elastic and mechanical properties of MHPs by increasing deformability and modifying microstructure of the film. The large tensile film stresses that typically occur from MHP processing are also significantly reduced using the additives, a characteristic which enables improved environmental stability. Lastly, the additives enable one-step processing of reproducible MHP devices in open-air with scalable processing methods such as blade coating. [https://meet.goto.com/807086845]