Researchers from the Department of Chemistry have uncovered the mechanism that causes new perovskite solar cells to break down, and a design approach that paves the way for a solution.
Solar cells harness energy from the sun and provide an alternative to non-renewable energy sources like fossil fuels to help reduce carbon dioxide emissions. Light-absorbing materials called perovskites are seen as a new type of solar cell that have shown exciting promise.
Although perovskites are cheaper to make than traditional silicon-based solar panels and deliver high efficiency, perovskites contain toxic lead substances, so alternative versions are being investigated.
Perovskite solar cells using tin instead of lead show promise but degrade rapidly, greatly decreasing their performance in a matter of days.
Now, in a study published in Nature Communications, Professor Saiful Islam’s group from the University of Bath working with Professor Saif Haque and colleagues at Imperial College London have determined 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 show how the selection of a crucial layer within the perovskite can mitigate against degradation under ambient conditions and increase stability.
Professor Saiful Islam said: “The important insights from our combined experimental-computational study will help researchers design more stable tin perovskites that show potential as new solar cells.”
Lanzetta et al (2021) “Degradation Mechanism of Hybrid Tin-Based Perovskite Solar Cells and the Critical Role of Tin (IV) Iodide” is published in Nature Communications 12. DOI: 10.1038/s41467-021-22864-z