Perovskite solar cells (PSCs) are a new generation of solar technology which has shown huge promise with regards to performance, but still suffers from several flaws preventing it from making the leap from the lab scale to the commercial scale. Many PSC show strong hysteresis in the jV curves – this means that a (much) higher efficiency is measured when scanning from open circuit to short circuit. The prevalent theory for explaining this hysteresis is that mobile ions in the material are responsible for it. Slight alterations to the chemical composition of the perovskite can help suppress hysteresis. The objective of this experiment is to investigate how the diffusion of iodide is affected by systematic altering of the perovskite structure.