Understanding Extrinsic and Intrinsic Ion Migration in Halide Perovskites Using Rutherford Backscattering

Halide perovskites exhibit remarkable properties for photovoltaic and optoelectronic applications, yet their susceptibility to ion migration within perovskites is a critical phenomenon that can profoundly impact their extended utilization in the devices. Tracking the ion migration is crucial for the performance and stability of the solar cells. Past investigations have generally focused on indirect or destructive experimental techniques used for probing ion migration. In this perspective, we investigate the extrinsic and intrinsic ion migration and their impact on perovskites solar cells by using the nondestructive technique Rutherford Backscattering Spectroscopy (RBS). We demonstrate the impact of ion migration for organic and inorganic lead halides perovskites devices after aging without external stress. Furthermore, the diverse methodologies employed to study extrinsic and intrinsic ion migration, interlayer diffusion between various layers of perovskite solar cell devices ranging from experimental techniques to XRUMP and Simnra simulations. These experimental findings indicate that I- ions are the most mobile, followed by MA+, Sn2+, Br- and Cs+ ions. We further demonstrate the dynamics of oxygen in the absence of external stress after aging.