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The Role of Potassium in the Segregation of MAPb(Br 0.6 I 0.4 ) 3 Mixed‐Halide Perovskite in Different Environments
Author(s) -
Özeren Mehmet Derya,
Botka Bea,
Pekker Áron,
Kamarás Katalin
Publication year - 2020
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000335
Subject(s) - halide , potassium bromide , perovskite (structure) , potassium , inorganic chemistry , passivation , chemistry , photoluminescence , bromide , absorption (acoustics) , oxygen , absorption spectroscopy , adsorption , phase (matter) , materials science , crystallography , optics , organic chemistry , optoelectronics , physics , layer (electronics) , composite material
Potassium addition to mixed‐halide perovskites is found to be a promising way to overcome their major stability issue, the segregation of the mixed phase to iodide and bromide‐rich regions. To fully exploit the potential of potassium addition, it is essential to achieve a better understanding of its working mechanism, and understand the limitations of the stabilization it provides. Photoluminescence emission spectra of MAPb(Br 0.6 I 0.4 ) 3 films are studied upon addition of KBr and KI under nitrogen and air atmosphere. The halide exchange between the added potassium salts and the perovskite is demonstrated. It is shown that the potassium addition does not passivate the surface, and it is therefore prone to oxygen and water absorption. The significant contribution of the adsorbed water to the prevention of halide segregation is discussed, which should be taken into account when the stability of the mixed‐halide films is evaluated under ambient conditions.