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Remarkable performance recovery in highly defective perovskite solar cells by photo-oxidation

Goetz, Katelyn P. ; Thome, Fabian T.F. ; An, Qingzhi ; Hofstetter, Yvonne J. ; Schramm, Tim ; Yangui, Aymen LU ; Kiligaridis, Alexander LU ; Loeffler, Markus ; Taylor, Alexander D. and Scheblykin, Ivan G. LU orcid , et al. (2023) In Journal of Materials Chemistry C 11(24). p.8007-8017
Abstract

Exposure to environmental factors is generally expected to cause degradation in perovskite films and solar cells. Herein, we show that films with certain defect profiles can display the opposite effect, healing upon exposure to oxygen under illumination. We tune the iodine content of methylammonium lead triiodide perovskite from understoichiometric to overstoichiometric and expose them to oxygen and light prior to the addition of the top layers of the device, thereby examining the defect dependence of their photooxidative response in the absence of storage-related chemical processes. The contrast between the photovoltaic properties of the cells with different defects is stark. Understoichiometric samples indeed degrade, demonstrating... (More)

Exposure to environmental factors is generally expected to cause degradation in perovskite films and solar cells. Herein, we show that films with certain defect profiles can display the opposite effect, healing upon exposure to oxygen under illumination. We tune the iodine content of methylammonium lead triiodide perovskite from understoichiometric to overstoichiometric and expose them to oxygen and light prior to the addition of the top layers of the device, thereby examining the defect dependence of their photooxidative response in the absence of storage-related chemical processes. The contrast between the photovoltaic properties of the cells with different defects is stark. Understoichiometric samples indeed degrade, demonstrating performance at 33% of their untreated counterparts, while stoichiometric samples maintain their performance levels. Surprisingly, overstoichiometric samples, which show low current density and strong reverse hysteresis when untreated, heal to maximum performance levels (the same as untreated, stoichiometric samples) upon the photooxidative treatment. A similar, albeit smaller-scale, effect is observed for triple cation and methylammonium-free compositions, demonstrating the general application of this treatment to state-of-the-art compositions. We examine the reasons behind this response by a suite of characterization techniques, finding that the performance changes coincide with microstructural decay at the crystal surface, reorientation of the bulk crystal structure for the understoichiometric cells, and a decrease in the iodine-to-lead ratio of all films. These results indicate that defect engineering is a powerful tool to manipulate the stability of perovskite solar cells.

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publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Materials Chemistry C
volume
11
issue
24
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85148770973
  • pmid:37362025
ISSN
2050-7526
DOI
10.1039/d2tc05077c
language
English
LU publication?
yes
id
3656d96f-e46d-4c50-a5a7-94dc3655cc88
date added to LUP
2023-03-16 15:44:34
date last changed
2024-04-18 05:10:11
@article{3656d96f-e46d-4c50-a5a7-94dc3655cc88,
  abstract     = {{<p>Exposure to environmental factors is generally expected to cause degradation in perovskite films and solar cells. Herein, we show that films with certain defect profiles can display the opposite effect, healing upon exposure to oxygen under illumination. We tune the iodine content of methylammonium lead triiodide perovskite from understoichiometric to overstoichiometric and expose them to oxygen and light prior to the addition of the top layers of the device, thereby examining the defect dependence of their photooxidative response in the absence of storage-related chemical processes. The contrast between the photovoltaic properties of the cells with different defects is stark. Understoichiometric samples indeed degrade, demonstrating performance at 33% of their untreated counterparts, while stoichiometric samples maintain their performance levels. Surprisingly, overstoichiometric samples, which show low current density and strong reverse hysteresis when untreated, heal to maximum performance levels (the same as untreated, stoichiometric samples) upon the photooxidative treatment. A similar, albeit smaller-scale, effect is observed for triple cation and methylammonium-free compositions, demonstrating the general application of this treatment to state-of-the-art compositions. We examine the reasons behind this response by a suite of characterization techniques, finding that the performance changes coincide with microstructural decay at the crystal surface, reorientation of the bulk crystal structure for the understoichiometric cells, and a decrease in the iodine-to-lead ratio of all films. These results indicate that defect engineering is a powerful tool to manipulate the stability of perovskite solar cells.</p>}},
  author       = {{Goetz, Katelyn P. and Thome, Fabian T.F. and An, Qingzhi and Hofstetter, Yvonne J. and Schramm, Tim and Yangui, Aymen and Kiligaridis, Alexander and Loeffler, Markus and Taylor, Alexander D. and Scheblykin, Ivan G. and Vaynzof, Yana}},
  issn         = {{2050-7526}},
  language     = {{eng}},
  number       = {{24}},
  pages        = {{8007--8017}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Journal of Materials Chemistry C}},
  title        = {{Remarkable performance recovery in highly defective perovskite solar cells by photo-oxidation}},
  url          = {{http://dx.doi.org/10.1039/d2tc05077c}},
  doi          = {{10.1039/d2tc05077c}},
  volume       = {{11}},
  year         = {{2023}},
}