Aspartate all-in-one doping strategy enables efficient all-perovskite tandems

Shun Zhou; Shiqiang Fu; Chen Wang; Weiwei Meng; Jin Zhou; Yuanrong Zou; Qingxian Lin; Lishuai Huang; Wenjun Zhang; Guojun Zeng; Dexin Pu; Hongling Guan; Cheng Wang; Kailian Dong; Hongsen Cui; Shuxin Wang; Ti Wang; Guojia Fang; Weijun Ke

doi:10.1038/s41586-023-06707-z

Aspartate all-in-one doping strategy enables efficient all-perovskite tandems

Nature. 2023 Dec;624(7990):69-73. doi: 10.1038/s41586-023-06707-z. Epub 2023 Nov 8.

Authors

Shun Zhou^#¹, Shiqiang Fu^#¹, Chen Wang^#¹, Weiwei Meng¹, Jin Zhou¹, Yuanrong Zou¹, Qingxian Lin¹, Lishuai Huang¹, Wenjun Zhang¹, Guojun Zeng¹, Dexin Pu¹, Hongling Guan¹, Cheng Wang¹, Kailian Dong¹, Hongsen Cui¹, Shuxin Wang¹, Ti Wang¹, Guojia Fang², Weijun Ke³

Affiliations

¹ Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China.
² Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China. gjfang@whu.edu.cn.
³ Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, China. weijun.ke@whu.edu.cn.

^# Contributed equally.

PMID: 37938775
DOI: 10.1038/s41586-023-06707-z

Abstract

All-perovskite tandem solar cells hold great promise in surpassing the Shockley-Queisser limit for single-junction solar cells^1-3. However, the practical use of these cells is currently hampered by the subpar performance and stability issues associated with mixed tin-lead (Sn-Pb) narrow-bandgap perovskite subcells in all-perovskite tandems^4-7. In this study, we focus on the narrow-bandgap subcells and develop an all-in-one doping strategy for them. We introduce aspartate hydrochloride (AspCl) into both the bottom poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) and bulk perovskite layers, followed by another AspCl posttreatment. We show that a single AspCl additive can effectively passivate defects, reduce Sn⁴⁺ impurities and shift the Fermi energy level. Additionally, the strong molecular bonding of AspCl-Sn/Pb iodide and AspCl-AspCl can strengthen the structure and thereby improve the stability of Sn-Pb perovskites. Ultimately, the implementation of AspCl doping in Sn-Pb perovskite solar cells yielded power conversion efficiencies of 22.46% for single-junction cells and 27.84% (27.62% stabilized and 27.34% certified) for tandems with 95% retention after being stored in an N₂-filled glovebox for 2,000 h. These results suggest that all-in-one AspCl doping is a favourable strategy for enhancing the efficiency and stability of single-junction Sn-Pb perovskite solar cells and their tandems.