Acetic Acid Assisted Crystallization Strategy for High Efficiency and Long-Term Stable Perovskite Solar Cell

Yong Li; Junwei Shi; Jianghui Zheng; Jueming Bing; Jianyu Yuan; Yongyoon Cho; Shi Tang; Meng Zhang; Yin Yao; Cho Fai Jonathan Lau; Da Seul Lee; Chwenhaw Liao; Martin A Green; Shujuan Huang; Wanli Ma; Anita W Y Ho-Baillie

doi:10.1002/advs.201903368

Acetic Acid Assisted Crystallization Strategy for High Efficiency and Long-Term Stable Perovskite Solar Cell

Adv Sci (Weinh). 2020 Jan 23;7(5):1903368. doi: 10.1002/advs.201903368. eCollection 2020 Mar.

Authors

Affiliations

¹ Australian Centre for Advanced Photovoltaics School of Photovoltaic and Renewable Energy Engineering University of New South Wales Sydney New South Wales 2052 Australia.
² Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Institute of Functional Nano & Soft Materials (FUNSOM) Soochow University Suzhou 215123 China.
³ Electron Microscope Unit Mark Wainwright Analytical Centre The University of New South Wales Sydney New South Wales 2052 Australia.
⁴ School of Engineering Macquarie University Sydney New South Wales 2109 Australia.
⁵ John Hooke Chair of Nanoscience School of Physics Faculty of Science The University of Sydney Sydney NSW 2006 Australia.

Abstract

Improving the quality of perovskite poly-crystalline film is essential for the performance of associated solar cells approaching their theoretical limit efficiency. Pinholes, unwanted defects, and nonperovskite phase can be easily generated during film formation, hampering device performance and stability. Here, a simple method is introduced to prepare perovskite film with excellent optoelectronic property by using acetic acid (Ac) as an antisolvent to control perovskite crystallization. Results from a variety of characterizations suggest that the small amount of Ac not only reduces the perovskite film roughness and residual PbI₂ but also generates a passivation effect from the electron-rich carbonyl group (C=O) in Ac. The best devices produce a PCE of 22.0% for Cs_0.05FA_0.80MA_0.15Pb(I_0.85Br_0.15)₃ and 23.0% for Cs_0.05FA_0.90MA_0.05Pb(I_0.95Br_0.05)₃ on 0.159 cm² with negligible hysteresis. This further improves device stability producing a cell that maintained 96% of its initial efficiency after 2400 h storage in ambient environment (with controlled relative humidity (RH) <30%) without any encapsulation.

Keywords: crystal engineering; perovskites; photovoltaic; stability.