Engineering

Ecology

Biology

Metallurgy

Materials science

Formamidinium

Telecommunications

Computer science

Perovskite (structure)

Inorganic chemistry

Chemical engineering

Iodide

Nanotechnology

Degradation (telecommunications)

Chemistry

Photovoltaics

Photovoltaic system

Nature Communications

Tin perovskites have emerged as promising alternatives to toxic lead perovskites in next-generation photovoltaics, but their poor environmental stability remains an obstacle towards more competitive performances. Therefore, a full understanding of their decomposition processes is needed to address these stability issues. Herein, we elucidate the degradation mechanism of 2D/3D tin perovskite films based on (PEA) 0.2 (FA) 0.8 SnI 3 (where PEA is phenylethylammonium and FA is formamidinium). We show that SnI 4 , a product of the oxygen-induced degradation of tin perovskite, quickly evolves into iodine via the combined action of moisture and oxygen. We identify iodine as a highly aggressive species that can further oxidise the perovskite to more SnI 4 , establishing a cyclic degradation mechanism. Perovskite stability is then observed to strongly depend on the hole transport layer chosen as the substrate, which is exploited to tackle film degradation. These key insights will enable the future design and optimisation of stable tin-based perovskite optoelectronics.

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