Zwitterion-Assisted Crystal Growth of 2D Perovskites with Unfavorable Phase Suppression for High-Performance Solar Cells

Hualin Zheng; Ting Zhang; Yafei Wang; Canzhou Li; Zhenhuang Su; Ze Wang; Hao Chen; Shihao Yuan; Yiding Gu; Long Ji; Jian Li; Shibin Li

doi:10.1021/acsami.1c19263

Zwitterion-Assisted Crystal Growth of 2D Perovskites with Unfavorable Phase Suppression for High-Performance Solar Cells

ACS Appl Mater Interfaces. 2022 Jan 12;14(1):814-825. doi: 10.1021/acsami.1c19263. Epub 2021 Dec 28.

Authors

Hualin Zheng¹, Ting Zhang¹, Yafei Wang¹, Canzhou Li², Zhenhuang Su³, Ze Wang¹, Hao Chen¹, Shihao Yuan¹, Yiding Gu¹, Long Ji¹, Jian Li¹, Shibin Li^{1

4}

Affiliations

¹ State Key Laboratory of Electronic Thin Films and Integrated Devices, and School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 610054, China.
² School of Information Science and Technology, Fudan University, 220 Handan Road, Shanghai 200433, China.
³ Shanghai Synchrotron Radiation Facility (SSRF), Zhangjiang Laboratory, Shanghai Advanced Research Institute, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai 201204, China.
⁴ Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou 313001, P. R. China.

PMID: 34963289
DOI: 10.1021/acsami.1c19263

Abstract

Despite two-dimensional (2D) Ruddlesden-Popper-phase layered perovskites (RPLPs) exhibiting excellent environmental stability, most solar cells based on 2D RPLP films are fabricated in a controlled inert atmosphere. Meanwhile, the poor charge transport of 2D RPLP films owing to the unfavorable phase arrangement and defects limits the efficiency of 2D RPLP solar cells. Here, we fabricate high-efficiency 2D RPLP solar cells in ambient air assisted by a zwitterion (ZW) additive. We show that the ZW additive suppresses the formation of the bottom 2D phases (n ≤ 2) and the top 3D-like phases in 2D RPLP films. These 2D phases usually grow parallel to the substrate and act as trap sites that inhibit charge transport in the vertical direction. The 3D-like phases, on the other hand, aggravate the long-term stability due to the intrinsic instability of MA⁺ cations. With improved phase distribution, crystal orientation, and reduced trap states in 2D RPLP films, efficient charge transport is obtained. Finally, a record-high open-circuit voltage (V_oc) of 1.19 V and a power conversion efficiency of 17.04% with an enhanced stability are achieved for (BA_0.9PEA_0.1)₂MA₃Pb₄I₁₃-based (n = 4) solar cells fabricated under high humidity (∼65% RH).

Keywords: 2D perovskite; ambient air; charge transport; defect passivation; phase distribution.