Direct Characterization of Type-I Band Alignment in 2D Ruddlesden–Popper Perovskites

Xinjue Zhong, Xiaojuan Ni, Siraj Sidhik, Hong Li, Aditya D. Mohite, Jean Luc Brédas, Antoine Kahn

Research output: Contribution to journalArticlepeer-review

Abstract

2D Ruddlesden–Popper halide perovskites have attracted considerable attention due to their desirable optoelectronic properties, high chemical and structural tunability, and improved environmental stability. However, the understanding of their structure–properties relationships is still limited. In particular, the energy level positions and band alignments at interfaces involving these materials, which are important features to control in the context of any applications, are still under debate. Here, the electronic structure of high-purity films of BA2MAn−1PbnI3n+1 for n = 1–5 (where BA stands for butylammonium and MA for methylammonium) is investigated, using optical absorption, ultraviolet, and inverse photoemission spectroscopies, and density functional theory calculations. This study determines the ionization energy and electron affinity of each compound and demonstrates a type-I band alignment for the BA2MAn−1PbnI3n+1 series. This study further describes the evolution of the exciton binding energy as a function of the thickness of the inorganic layers.

Original languageEnglish (US)
Article number2202333
JournalAdvanced Energy Materials
Volume12
Issue number45
DOIs
StatePublished - Dec 1 2022

All Science Journal Classification (ASJC) codes

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

Keywords

  • 2D Ruddlesden–Popper perovskites
  • electronic structures
  • exciton binding energy
  • type-I band alignment

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