Multifunctional Polymeric-Nanofiber Reinforcement of Perovskite Solar Cells for Improved Mechanical Stability without Performance Trade-Off

Metal halide perovskites have been demonstrated to be extremely fragile materials that can fracture at low applied stresses. Previous efforts to mechanically reinforce perovskite films have focused on the extrinsic mechanical shielding such as polymer scaffolding, but these implementations demonstrated to date either have performance trade-offs or require complex manufacturing steps. I will discuss a perovskite-polymeric nanofiber composite that increases the mechanical toughness without an efficiency tradeoff. The fracture energy, <i>G</i>_c, of this nanocomposite is 500% higher (2.34 ± 1.67 J m⁻²) than in pristine perovskite (0.40 ± 0.16 J m⁻²). The nanocomposites were observed via scanning electron microscopy (SEM) and atomic force microscopy (AFM) to be homogeneous in the vertical direction, and x-ray diffraction (XRD) showed that the films were of similar quality to pristine perovskite (no lead iodide growth), but with a decrease in orientation. Furthermore, we show that there is no trade-off in device efficiency despite the integration of the insulating nanofibers, which we show is likely due to beneficial light scattering that increases current generation.