Combining Efficiency and Stability in Mixed Tin–Lead Perovskite Solar Cells by Capping Grains with an Ultrathin 2D Layer

Mingyang Wei, Ke Xiao, Grant Walters, Renxing Lin, Yongbiao Zhao, Makhsud I. Saidaminov, Petar Todorović, Andrew Johnston, Ziru Huang, Haijie Chen, Aidong Li, Jia Zhu, Zhenyu Yang, Ya-Kun Wang, Andrew H. Proppe, Shana O. Kelley, Yi Hou, Oleksandr Voznyy, Hairen Tan, E. Sargent

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The development of narrow-bandgap (Eg ≈ 1.2 eV) mixed tin–lead (Sn–Pb) halide perovskites enables all-perovskite tandem solar cells. Whereas pure-lead halide perovskite solar cells (PSCs) have advanced simultaneously in efficiency and stability, achieving this crucial combination remains a challenge in Sn–Pb PSCs. Here, Sn–Pb perovskite grains are anchored with ultrathin layered perovskites to overcome the efficiency-stability tradeoff. Defect passivation is achieved both on the perovskite film surface and at grain boundaries, an approach implemented by directly introducing phenethylammonium ligands in the antisolvent. This improves device operational stability and also avoids the excess formation of layered perovskites that would otherwise hinder charge transport. Sn–Pb PSCs with fill factors of 79% and a certified power conversion efficiency (PCE) of 18.95% are reported—among the highest for Sn–Pb PSCs. Using this approach, a 200-fold enhancement in device operating lifetime is achieved relative to the nonpassivated Sn–Pb PSCs under full AM1.5G illumination, and a 200 h diurnal operating time without efficiency drop is achieved under filtered AM1.5G illumination.
Original languageEnglish (US)
Pages (from-to)1907058
JournalAdvanced Materials
Volume32
Issue number12
DOIs
StatePublished - Mar 2020
Externally publishedYes

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