Title: High‐Efficiency Quasi‐2D Perovskite Solar Cells Incorporating 2,2′‐Biimidazolium Cation

Abstract

Quasi‐2D perovskites are attractive because of their improved stability compared with 3D perovskites counterparts; however, they suffer from poor performance due to the insulating organic cation spacers. To resolve this issue, a strategy of replacing the insulating spacer with conducting spacer is proposed which successfully converts the spacer from a charge‐transporting “barrier” to charge‐transporting “bridge.” Specifically, an alkyl linker‐free, fully conjugated aromatic 2,2′‐biimidazolium (BIDZ) cation is introduced as a spacer to compose quasi‐2D perovskites. Density functional theory (DFT) simulation results show that the lowest unoccupied molecular orbital (LUMO) level localizes on BIDZ and the highest occupied molecular orbital (HOMO) level is on the perovskite. However, both HOMO and LUMO levels localize on perovskite slabs for the well‐known phenethylammonium (PEA)‐based 2D perovskites. The strong electronic coupling between BIDZ and 3D perovskite slabs improves carrier mobilities even for a low‐weak‐crystallinity and random‐orientated quasi‐2D perovskite film. As a result, a remarkable power conversion efficiency up to 11.4% ( n  = 5) is achieved, which is much higher than that of PEA‐based random‐orientated quasi‐2D perovskites with the same processing condition (6.5%). The strategy paves the way to highly efficient and stable quasi‐2D perovskites solar cells through designing new organic spacer cations.

Authors:

Fu, Weifei ^[1]; Zhao, Ting ^[1]; Liu, Hongbin ^[2]; Lin, Francis  ^[1];

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Zuo, Lijian ^[1]; Li, Xiaosong ^[2]; Jen, Alex K. -Y. ^[3]

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+ Show Author Affiliations

1. Department of Materials Science and Engineering University of Washington Seattle WA 98195 USA
2. Department of Chemistry University of Washington Seattle WA 98195 USA
3. Department of Materials Science and Engineering University of Washington Seattle WA 98195 USA, Department of Chemistry University of Washington Seattle WA 98195 USA, Department of Chemistry City University of Hong Kong Tat Chee Avenue 999077 Kowloon Hong Kong, Department of Materials Science and Engineering City University of Hong Kong Tat Chee Avenue 999077 Kowloon Hong Kong

Publication Date:

Sun Feb 07 00:00:00 EST 2021

Sponsoring Org.:

USDOE

OSTI Identifier:

1804806

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Solar RRL

Additional Journal Information:

Journal Name: Solar RRL Journal Volume: 5 Journal Issue: 3; Journal ID: ISSN 2367-198X

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

Germany

Language:

English