All-perovskite tandem solar cells with 24.2% certified efficiency and area over 1 cm2 using surface-anchoring zwitterionic antioxidant

Ke Xiao, Renxing Lin, Qiaolei Han, Yi Hou, Zhenyuan Qin, Hieu T. Nguyen, Jin Wen, Mingyang Wei, Vishal Yeddu, Makhsud I. Saidaminov, Yuan Gao, Xin Luo, Yurui Wang, Han Gao, Chunfeng Zhang, Jun Xu, Jia Zhu, Edward H. Sargent, Hairen Tan*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    512 Citations (Scopus)

    Abstract

    Monolithic all-perovskite tandem solar cells offer an avenue to increase power conversion efficiency beyond the limits of single-junction cells. It is an important priority to unite efficiency, uniformity and stability, yet this has proven challenging because of high trap density and ready oxidation in narrow-bandgap mixed lead–tin perovskite subcells. Here we report simultaneous enhancements in the efficiency, uniformity and stability of narrow-bandgap subcells using strongly reductive surface-anchoring zwitterionic molecules. The zwitterionic antioxidant inhibits Sn2+ oxidation and passivates defects at the grain surfaces in mixed lead–tin perovskite films, enabling an efficiency of 21.7% (certified 20.7%) for single-junction solar cells. We further obtain a certified efficiency of 24.2% in 1-cm2-area all-perovskite tandem cells and in-lab power conversion efficiencies of 25.6% and 21.4% for 0.049 cm2 and 12 cm2 devices, respectively. The encapsulated tandem devices retain 88% of their initial performance following 500 hours of operation at a device temperature of 54–60 °C under one-sun illumination in ambient conditions.

    Original languageEnglish
    Pages (from-to)870-880
    Number of pages11
    JournalNature Energy
    Volume5
    Issue number11
    DOIs
    Publication statusPublished - Nov 2020

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