Electronic Modulation in Site-Selective Occupation of Quasi-2D Triangular-Lattice Cs2CuCl4- xBrx Perovskite Probed by Surface-Sensitive Characterization

Arramel, Aozhen Xie, Xinmao Yin, Chi Sin Tang, Angga Dito Fauzi, Xiao Chi, Caozheng Diao, Muhammad Fauzi Sahdan, Muhammad Danang Birowosuto, Cuong Dang, Andrivo Rusydi, Andrew Thye Shen Wee

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

A controllable electronic manipulation in a frustrated magnetic system such as solution-based two-dimensional (2D) all-inorganic perovskites offers a possible route for their integrations with electronic and magnetic devices for their advanced applications. Here, we perform element-specific investigations of an emergent class of quasi-2D all-inorganic perovskites Cs2CuCl4-xBrx with (0 ≤ x ≤ 4) using a combination of synchrotron-radiation photoelectron techniques. Surface- and element-sensitive X-ray absorption spectroscopy spectra of Cu L2,3 edges indicate strong electronic transition that is largely influenced by their halogen content at room temperature. This implies that site-selective occupation largely dominates the electronic transition across the unoccupied states of these series since chlorine atoms possess a stronger electronegative character than bromine atoms. Moreover, the implication of halogen site is reflected in the valence band of Cl-rich copper perovskite in which the valence band edge is closer to Fermi energy (EF) than that of the Br-rich compound. Furthermore, X-ray magnetic circular dichroism spectra of mixed ratio and Br-rich compounds exhibit antiferromagnetism at room temperature. These site-specific magnetic-spectroscopic results are corroborated by density functional theory calculations. The strong electronic modulation and the local magnetic spectroscopy results in these solution-based and low-temperature-growth materials will pave the way toward energy- and cost-efficient perovskite devices.

Original languageEnglish
Pages (from-to)4114-4122
Number of pages9
JournalACS Applied Materials and Interfaces
Volume12
Issue number3
DOIs
Publication statusPublished - 22 Jan 2020
Externally publishedYes

Keywords

  • density functional theory
  • quasi-2D copper perovskite
  • X-ray absorption spectroscopy
  • X-ray circular magnetic dichroism

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