Potassium- and Rubidium-Passivated Alloyed Perovskite Films: Optoelectronic Properties and Moisture Stability.
Pearson, Andrew J
Friend, Richard H
Stranks, Samuel D
ACS Energy Lett
American Chemical Society (ACS)
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Abdi-Jalebi, M., Andaji-Garmaroudi, Z., Pearson, A. J., Divitini, G., Cacovich, S., Philippe, B., Rensmo, H., et al. (2018). Potassium- and Rubidium-Passivated Alloyed Perovskite Films: Optoelectronic Properties and Moisture Stability.. ACS Energy Lett, 3 (11), 2671-2678. https://doi.org/10.1021/acsenergylett.8b01504
Halide perovskites passivated with potassium or rubidium show superior photovoltaic device performance compared to unpassivated samples. However, it is unclear which passivation route is more effective for film stability. Here, we directly compare the optoelectronic properties and stability of thin films when passivating triple-cation perovskite films with potassium or rubidium species. The optoelectronic and chemical studies reveal that the alloyed perovskites are tolerant toward higher loadings of potassium than rubidium. Whereas potassium complexes with bromide from the perovskite precursor solution to form thin surface passivation layers, rubidium additives favor the formation of phase-segregated micron-sized rubidium halide crystals. This tolerance to higher loadings of potassium allows us to achieve superior luminescent properties with potassium passivation. We also find that exposure to a humid atmosphere drives phase segregation and grain coalescence for all compositions, with the rubidium-passivated sample showing the highest sensitivity to nonperovskite phase formation. Our work highlights the benefits but also the limitations of these passivation approaches in maximizing both optoelectronic properties and the stability of perovskite films.
Engineering and Physical Sciences Research Council (grant number: EP/M005143/1)
Engineering and Physical Sciences Research Council (EP/M005143/1)
Lloyd's Register Foundation (via University of Southampton) (unknown)
European Research Council (756962)
External DOI: https://doi.org/10.1021/acsenergylett.8b01504
This record's URL: https://www.repository.cam.ac.uk/handle/1810/283234