Pinning Down the Anomalous Light Soaking Effect toward High-Performance and Fast-Response Perovskite Solar Cells: The Ion-Migration-Induced Charge Accumulation

Teng Zhang, Sin Hang CHEUNG, Xiangyue Meng, Lei Zhu, Yang Bai, Carr Hoi Yi Ho, Shuang Xiao, Qingzhong Xue, Shu Kong SO, Shihe Yang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)

Abstract

The light soaking effect (LSE) is widely known in perovskite solar cells (PVSCs), but its origin is still elusive. In this study, we show that in common with hysteresis, the LSE is owed to the ion migration in PVSCs. Driven by the photovoltage, the mobile ions in the perovskite materials (MA+/I-) migrate to the selective contacts, forming a boosted P-i-N junction resulting in enhanced charge separation. Besides, the mobile ions (MA+) can soften and suture the PCBM/perovskite interface and thus reduce the trap density, in keeping with a higher open-circuit voltage. Finally, almost LSE-free PVSCs can be prepared by using 0.1 wt % MAI-doped PCBM as the electron transport material, whereas overdoping (1 wt % MAI doping) makes the LSE even more pronounced due to excess mobile ions that need time to migrate to reach a new quasi-static state.

Original languageEnglish
Pages (from-to)5069-5076
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume8
Issue number20
DOIs
Publication statusPublished - 19 Oct 2017

Scopus Subject Areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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