The Role of Oxygen in the Degradation of Methylammonium Lead Trihalide Perovskite Photoactive Layers |
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| Authors: | Nicholas Aristidou Dr Irene Sanchez‐Molina Thana Chotchuangchutchaval Dr Michael Brown Dr Luis Martinez Dr Thomas Rath Prof Saif A Haque |
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| Affiliation: | Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom) |
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| Abstract: | In this paper we report on the influence of light and oxygen on the stability of CH3NH3PbI3 perovskite‐based photoactive layers. When exposed to both light and dry air the mp‐Al2O3/CH3NH3PbI3 photoactive layers rapidly decompose yielding methylamine, PbI2, and I2 as products. We show that this degradation is initiated by the reaction of superoxide (O2?) with the methylammonium moiety of the perovskite absorber. Fluorescent molecular probe studies indicate that the O2? species is generated by the reaction of photoexcited electrons in the perovskite and molecular oxygen. We show that the yield of O2? generation is significantly reduced when the mp‐Al2O3 film is replaced with an mp‐TiO2 electron extraction and transport layer. The present findings suggest that replacing the methylammonium component in CH3NH3PbI3 to a species without acid protons could improve tolerance to oxygen and enhance stability. |
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| Keywords: | methylammonium lead triiodide perovskites solar cells spectroscopy stability |
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