Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells

Nicholas Aristidou, Christopher Eames, Irene Sanchez-Molina, Xiangnan Bu, Jan Kosco, M. Saiful Islam, Saif A. Haque

Research output: Contribution to journalArticle

280 Citations (Scopus)

Abstract

Methylammonium lead halide perovskites are attracting intense interest as promising materials for next-generation solar cells, but serious issues related to long-term stability need to be addressed. Perovskite films based on CH3NH3PbI3 undergo rapid degradation when exposed to oxygen and light. Here, we report mechanistic insights into this oxygen-induced photodegradation from a range of experimental and computational techniques. We find fast oxygen diffusion into CH3NH3PbI3 films is accompanied by photo-induced formation of highly reactive superoxide species. Perovskite films composed of small crystallites show higher yields of superoxide and lower stability. Ab initio simulations indicate that iodide vacancies are the preferred sites in mediating the photo-induced formation of superoxide species from oxygen. Thin-film passivation with iodide salts is shown to enhance film and device stability. The understanding of degradation phenomena gained from this study is important for the future design and optimization of stable perovskite solar cells.

Original languageEnglish
Article number15218
Number of pages10
JournalNature Communications
Volume8
Early online date11 May 2017
DOIs
Publication statusPublished - 11 May 2017

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