Controlling competing photochemical reactions stabilizes perovskite solar cells

Metal halide perovskites have become a popular material system for fabricating photovoltaics and various optoelectronic devices. However, long-term reliability must be assured. Instabilities are manifested as light-induced ion migration and segregation, which can lead to material degradation. Discor...

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Bibliographic Details
Published in:Nature photonics 2019-08, Vol.13 (8), p.532-539
Main Authors: Motti, Silvia G., Meggiolaro, Daniele, Barker, Alex J., Mosconi, Edoardo, Perini, Carlo Andrea Riccardo, Ball, James M., Gandini, Marina, Kim, Min, De Angelis, Filippo, Petrozza, Annamaria
Format: Article
Language:English
Subjects:
140/125
639/301
639/301/1005
639/638/439
639/766
Applied and Technical Physics
Carrier traps
Controlled conditions
Defects
Ion migration
Light
Light effects
Metal halides
Optoelectronic devices
Perovskites
Photochemical reactions
Photochemicals
Photoluminescence
Photons
Photovoltaic cells
Photovoltaics
Physics
Physics and Astronomy
Quantum Physics
Solar cells
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Summary:Metal halide perovskites have become a popular material system for fabricating photovoltaics and various optoelectronic devices. However, long-term reliability must be assured. Instabilities are manifested as light-induced ion migration and segregation, which can lead to material degradation. Discordant reports have shown a beneficial role of ion migration under illumination, leading to defect healing. By combining ab initio simulations with photoluminescence measurements under controlled conditions, we demonstrate that photo-instabilities are related to light-induced formation and annihilation of defects acting as carrier trap states. We show that these phenomena coexist and compete. In particular, long-living carrier traps related to halide defects trigger photoinduced material transformations, driving both processes. Defect formation can be controlled by blocking under-coordinated surface sites, which act as a defect reservoir. By use of a passivation strategy we are thus able to stabilize the perovskite layer, leading to improved optoelectronic material quality and enhanced photostability in solar cells. The photo-instability of perovskite solar cells is investigated and controlled by the use of a passivation strategy.
ISSN:1749-4885
1749-4893
DOI:10.1038/s41566-019-0435-1