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Title: High Tolerance to Iron Contamination in Lead Halide Perovskite Solar Cells

The relationship between charge-carrier lifetime and the tolerance of lead halide perovskite (LHP) solar cells to intrinsic point defects has drawn much attention by helping to explain rapid improvements in device efficiencies. However, little is known about how charge-carrier lifetime and solar cell performance in LHPs are affected by extrinsic defects (i.e., impurities), including those that are common in manufacturing environments and known to introduce deep levels in other semiconductors. Here, we evaluate the tolerance of LHP solar cells to iron introduced via intentional contamination of the feedstock and examine the root causes of the resulting efficiency losses. We find that comparable efficiency losses occur in LHPs at feedstock iron concentrations approximately 100 times higher than those in p-type silicon devices. Photoluminescence measurements correlate iron concentration with nonradiative recombination, which we attribute to the presence of deep-level iron interstitials, as calculated from first-principles, as well as iron-rich particles detected by synchrotron-based X-ray fluorescence microscopy. At moderate contamination levels, we witness prominent recovery of device efficiencies to near-baseline values after biasing at 1.4 V for 60 s in the dark. We theorize that this temporary effect arises from improved charge-carrier collection enhanced by electric fields strengthened from ion migration toward interfaces.more » Lastly, our results demonstrate that extrinsic defect tolerance contributes to high efficiencies in LHP solar cells, which inspires further investigation into potential large-scale manufacturing cost savings as well as the degree of overlap between intrinsic and extrinsic defect tolerance in LHPs and 'perovskite-inspired' lead-free stable alternatives.« less
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [3] ;  [1] ;  [4] ; ORCiD logo [1] ;  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Univ. of Cambridge, Cambridge (United Kingdom)
  3. Argonne National Lab. (ANL), Lemont, IL (United States)
  4. Colorado School of Mines, Golden, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1936-0851
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 11; Journal Issue: 7; Journal ID: ISSN 1936-0851
American Chemical Society (ACS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Next Generation of Materials by Design: Incorporating Metastability (CNGMD)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; extrinsic defects; hysteresis; impurities; methylammonium lead iodide; photoluminescence; photovoltaics; recombination
OSTI Identifier: