Impact of n-Butylammonium Bromide on the Chemical and Electronic Structure of Double-Cation Perovskite Thin Films

Dirk Hauschild*, Linsey Seitz, Saba Gharibzadeh, Ralph Steininger, Nan Jiang, Wanli Yang, Ulrich Wilhelm Paetzold, Clemens Heske, Lothar Weinhardt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


2D/3D perovskite heterostructures have emerged as a promising material composition to reduce nonradiative recombination in perovskite-based LEDs and solar cells. Such heterostructures can be created by a surface treatment with large organic cations, for example, n-butylammonium bromide (BABr). To understand the impact of the BABr surface treatment on the double-cation (Cs0.17FA0.83Pb(I0.6Br0.4)3) (FA = formamidinium) perovskite thin film and further optimize the corresponding structures, an in-depth understanding of the chemical and electronic properties of the involved surfaces, interfaces, and bulk is required. Hence, we study the impact of the BABr treatment with a combination of surface-sensitive X-ray photoelectron spectroscopy and bulk-sensitive resonant inelastic soft X-ray scattering (RIXS). A quantitative analysis of the BABr-treated perovskite thin film shows a modified chemical perovskite surface environment of carbon, nitrogen, bromine, iodine, and lead, indicating that the treatment leads to a perovskite surface with a modified composition and bonding structure. With K-edge RIXS, the local environment at the nitrogen and carbon atoms is probed, allowing us to identify the presence of BABr in the perovskite bulk albeit with a modified bonding environment. This, in turn, identifies a "hidden parameter"for the optimization of the BABr treatment and overall performance of 2D/3D perovskite solar cell absorbers.

Original languageEnglish (US)
Pages (from-to)53202-53210
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number44
StatePublished - Nov 10 2021


  • 2D/3D perovskite heterostructure
  • X-ray absorption spectroscopy
  • X-ray emission spectroscopy
  • n-butylammonium bromide surface treatment
  • perovskite-based solar cells
  • photoelectron spectroscopy
  • resonant inelastic soft X-ray scattering

ASJC Scopus subject areas

  • Materials Science(all)


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