Researchers at Imperial college London and the University of Bath have found the mechanism that causes perovskite-based solar cells to break down, and suggested a potential solution.

Degradation mechanism of hybrid tin-based perovskite solar cells and the critical role of tin (IV) iodide image

Versions of perovskite solar cells that use tin instead of lead tend to degrade quickly. Now, the researchers at Imperial and the University of Bath have shown how these perovskites degrade to tin iodide, which, when exposed to moisture and oxygen, forms iodine. This iodine then helps form more tin iodide, causing cyclic degradation.

The team also showed how the selection of a crucial layer within the perovskite can mitigate against degradation under ambient conditions and increase stability. They hope this will help researchers design more stable high-performance tin perovskites that show potential as new solar cells.

Lead researcher Professor Saif Haque, from the Department of Chemistry at Imperial, said: "Knowing the mechanism will help us overcome a major stumbling block for this exciting new technology. Our results will also enable the design of tin perovskite materials with improved stability, paving the way for cheaper, more flexible solar harvesting devices."