High performance low-bandgap perovskite solar cells based on a high-quality mixed Sn-Pb perovskite film prepared by vacuum-assisted thermal annealing

Meiyue Liu, Ziming Chen, Qifan Xue, Sin Hang CHEUNG, Shu Kong SO, Hin Lap Yip*, Yong Cao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Tandem perovskite solar cells are an effective concept to overcome the Shockley-Queisser limit of a single-junction perovskite solar cell. For a high-performance tandem cell, besides a wide-bandgap perovskite top cell, a high-quality low-bandgap perovskite bottom cell with an optimum bandgap of ∼1.2 eV is urgently needed. Moreover, a simple process technique needs to be developed for a high-quality perovskite film with good reproducibility, in order to further simplify the whole tandem-cell fabrication. Accordingly, we develop a simple one-step process (vacuum-assisted thermal annealing) for a high-quality low-bandgap CH3NH3Sn0.5Pb0.5IxCl3-x film, where the absorption edge can exceed 1000 nm. After comparing CH3NH3Sn0.5Pb0.5IxCl3-x films annealed in a vacuum and in a nitrogen environment, we find that vacuum-assisted thermal annealing can result in CH3NH3Sn0.5Pb0.5IxCl3-x films with better film coverage and crystallinity. This process can also accelerate the sublimation of methylammonium chloride and reduce the trap density in the CH3NH3Sn0.5Pb0.5IxCl3-x film. With this process, we successfully fabricated an efficient low-bandgap perovskite solar cell with a power conversion efficiency of more than 12% and good device reproducibility as well as long-term stability.

Original languageEnglish
Pages (from-to)16347-16354
Number of pages8
JournalJournal of Materials Chemistry A
Volume6
Issue number34
DOIs
Publication statusPublished - 2018

Scopus Subject Areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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