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Title: Defect Passivation of Organic–Inorganic Hybrid Perovskites by Diammonium Iodide toward High-Performance Photovoltaic Devices

The polycrystalline feature of solutionprocessed perovskite film and its ionic nature inevitably incur substantial crystallographic defects, especially at the film surface and the grain boundaries (GBs). Here, a simple defect passivation method was exploited by post-treating CH 3NH 3PbI 3 (MAPbI 3) film with a rationally selected diammonium iodide. The molecular structure of the used diammonium iodide was discovered to play a critical role in affecting the phase purity of treated MAPbI 3. Both NH 3I(CH 2) 4NH 3I and NH 3I(CH 2) 2O(CH 2) 2NH 3I (EDBE) induce three-dimensional (3D) to two-dimensional (2D) perovskite phase transformation during the treatment while only NH 3I(CH 2) 8NH 3I (C 8) successfully passivates perovskite surface and GBs without forming 2D perovskite because of the elevated activation energy arising from its unique anti-gauche isomerization. In conclusion, defect passivation of MAPbI 3 was clearly confirmed by scanning Kelvin probe microscopy (SKPM) and time-resolved photoluminescence (TRPL) studies, which results in the reduced recombination loss in derived devices. Consequently, the perovskite solar cell with C 8 passivation showed a much improved power conversion efficiency (PCE) of 17.60% compared to the control device PCE of 14.64%.
 [1] ;  [1] ;  [1] ;  [1] ;  [2]
  1. Univ. of Washington, Seattle, WA (United States). Dept. of Materials Science and Engineering
  2. Univ. of Washington, Seattle, WA (United States). Dept. of Materials Science and Engineering; Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry
Publication Date:
Report Number(s):
Journal ID: ISSN 2380-8195
Grant/Contract Number:
EE0006710; DMR-1608279; N00014-14-1- 0246; FA2386-15-1-410
Accepted Manuscript
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 1; Journal Issue: 4; Journal ID: ISSN 2380-8195
American Chemical Society (ACS)
Research Org:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF); US Department of the Navy, Office of Naval Research (ONR); Asian Office of Aerospace R&D
Contributing Orgs:
Collaborative Innovation Center of Suzhou Nano Science and Technology; Boeing-Johnson Foundation
Country of Publication:
United States
OSTI Identifier: