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Title: Modulation of PEDOT:PSS pH for efficient inverted perovskite solar cells with reduced potential loss and enhanced stability

Inverted p-i-n perovskite solar cells (PVSCs) using PEDOT:PSS as the hole-transporting layer (HTL) is one of the most widely adopted device structures thus far due to its facile processability and good compatibility for high throughput manufacturing processes. However, most of the PEDOT:PSS-based CH3NH3PbI3 PVSCs reported to date suffered an inferior open-circuit voltage (VOC) (0.88-0.95 V) compared to that (1.05-1.12 V) obtained for common CH3NH3PbI3 PVSCs, revealing a severe potential loss issue. Herein, we describe a simple method to alleviate this problem by tuning the pH value of PEDOT:PSS with a mild base, imidazole. Accompanied by the pH modulation, the blended imidazole concurrently tailors the surface texture and electronic properties of PEDOT:PSS to promote the quality and crystallization of the perovskite film deposited on top of it and enable better energy-level alignment at this corresponding interface. Consequently, the PVSC using this modified PEDOT:PSS HTL yields an enhanced power conversion efficiency (PCE) of 15.7% with an enlarged VOC of 1.06 V and improved long-term stability. Lastly, these outperform the pristine device showing a PCE of 12.7% with a much smaller VOC of 0.88 V and unsatisfactory environmental stability.
Authors:
 [1] ;  [2] ;  [3] ;  [2]
  1. Univ. of Washington, Seattle, WA (United States); Univ. of Michigan - Shanghai Jiao Tong Univ. Joint Institute, Shanghai (China)
  2. Univ. of Washington, Seattle, WA (United States)
  3. Univ. of Michigan - Shanghai Jiao Tong Univ. Joint Institute, Shanghai (China)
Publication Date:
OSTI Identifier:
1343603
Report Number(s):
DOE-UW-Jen-30
Journal ID: ISSN 1944-8244; TRN: US1701291
Grant/Contract Number:
EE0006710
Type:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 8; Journal Issue: 46; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Contributing Orgs:
This work was partially supported by the Office of Naval Research (N00014-14-1-0246), the National Science Foundation (DMR-1608279), the Department of Energy SunShot (DE-EE0006710), and the Asian Office of Aerospace R&D (FA2386-15-1-4106). Q.W. thanks the financial support from the China Scholarship Council (CSC N 201506230080). A.K.- Y.J. is thankful for financial support from the Boeing−Johnson Foundation. The authors would like to thank Fatemeh Zabihi, University of MichiganShanghai Jiao Tong University Joint Institute, for performing the XPS and UPS analyses.
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; PEDOT:PSS; pH; potential loss; environmental stability; perovskite solar cells