A Cytop Insulating Tunneling Layer for Efficient Perovskite Solar Cells

Journal Article · 15 September 2017 · Small Methods

DOI: https://doi.org/10.1002/smtd.201700244 · OSTI ID:1392145

Zheng, Yifan  ^[1]; Shi, Wei ^[2]; Kong, Jaemin ^[3]; Huang, Di ^[3]; Katz, Howard E. ^[4]; Yu, Junsheng ^[5]; Taylor, André D.  ^[3]

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1. State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Information University of Electronic Science and Technology of China (UESTC) Chengdu 610054 P. R. China, Department of Chemical and Environmental Engineering Yale University New Haven CT 06511 USA
2. State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Information University of Electronic Science and Technology of China (UESTC) Chengdu 610054 P. R. China, Department of Materials Science and Engineering Johns Hopkins University 3400 North Charles Street Baltimore MD 21218 USA
3. Department of Chemical and Environmental Engineering Yale University New Haven CT 06511 USA
4. Department of Materials Science and Engineering Johns Hopkins University 3400 North Charles Street Baltimore MD 21218 USA
5. State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Information University of Electronic Science and Technology of China (UESTC) Chengdu 610054 P. R. China

Abstract Improvement of the interface between the perovskite layer and the electron‐transport layer (ETL) is critical toward the advancement of planar perovskite solar cells (PSCs). It is important to obtain a uniform and pinhole‐free ETL that can minimize film defects and thus undesirable electron–hole recombination between the perovskite layer and cathode. However, this is extremely difficult because the rough perovskite surface causes charge–carrier recombination, facilitates large leakage currents, and inevitably deteriorates the electron‐extraction efficiency. Here, fluorine‐containing insulating polymers, poly(perfluorobutenylvinylether) (Cytop), are used as the tunneling layer in planar PSCs for the first time, resulting in a significant improvement in the power conversion efficiency (PCE) from 11.9% to over 14.5%. It is found that the Cytop layer not only fills the pinholes of the perovskite surface to decrease the trap concentration, but can also provide a strong electron‐extraction ability to facilitate charge‐transfer process and restrict charge recombination. In addition, improved water resistance is demonstrated using Cytop, which significantly extends the PSC lifetime (78% of initial PCE vs 22% for control after 1500 h) and increases the practical applicability.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐FG02‐07ER46465
• OSTI ID: 1392145
• Journal Information: Small Methods, Journal Name: Small Methods Vol. 1 Journal Issue: 10; ISSN 2366-9608
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: United States
• Language: English