Universal Approach for Managing Iodine Migration in Inverted Single-Junction and Tandem Perovskite Solar Cells

Zhenhua Song, Kexuan Sun, Yuanyuan Meng*, Zewei Zhu, Yaohua Wang, Weifu Zhang, Yang Bai, Xiaoyi Lu, Ruijia Tian, Chang Liu*, Ziyi Ge*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Despite significant progress in the power-conversion efficiency (PCE) of perovskite solar cells (PSCs), the instability of devices remains a considerable obstacle for commercial applications. This instability primarily originates from the migration of halide ions—particularly iodide ions (I). Under light exposure and thermal stress, I migrates and transforms into I2, leading to irreversible degradation and performance loss. To address this issue, we introduced the additive 2,1,3-benzothiadiazole,5,6-difluoro-4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) (BT2F-2B) into the perovskite. The strong coordination between the unhybridized p orbital and lone-pair electrons from I inhibits the deprotonation of MAI/FAI and the subsequent conversion of I to I₂. The highly electronegative fluorine enhances its electrostatic interaction with I. Consequently, the synergistic effect of BT2F-2B effectively suppresses the decomposition of perovskite and the defect density of the iodide vacancies. This approach delivers a PCE over 26% for inverted single-junction PSCs, with exceptional operational stability. According to the ISOS-L-3 testing protocol (maximum power point tracking at 85 °C and 50% relative humidity), treated PSCs retain 85% of their original PCE after 1000 h of aging. When the BT2F-2B is applied to a wide-bandgap (1.77 eV) perovskite system, the PCE of all-perovskite tandem solar cells reaches 27.8%, confirming the universality of the proposed strategy.

Original languageEnglish
JournalAdvanced Materials
DOIs
Publication statusAccepted/In press - 2024
Externally publishedYes

Keywords

  • halide migration
  • iodide ion migration
  • light stability
  • operational stability
  • perovskite solar cells

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Song, Z., Sun, K., Meng, Y., Zhu, Z., Wang, Y., Zhang, W., Bai, Y., Lu, X., Tian, R., Liu, C., & Ge, Z. (Accepted/In press). Universal Approach for Managing Iodine Migration in Inverted Single-Junction and Tandem Perovskite Solar Cells. Advanced Materials. https://doi.org/10.1002/adma.202410779