Ce(iv)-centered charge-neutral perovskite layers topochemically derived from anionic [CeTa₂O₇]^- layers

Area of Science:

• Materials Science
• Solid-State Chemistry

Background:

• Layered perovskites offer tunable properties for electronics, catalysis, optics, energy, and magnetics.
• Chemical modification via ion exchange creates nanosheets from layered perovskites.

Purpose of the Study:

• To introduce a new structural concept of "charge-neutral perovskite layers" by manipulating the perovskite layer itself.
• To synthesize and characterize charge-neutral [Ce^IVTa₂O₇] layers and explore their properties.

Main Methods:

• Soft chemical oxidative reaction to synthesize charge-neutral [Ce^IVTa₂O₇] from anionic [Ce^IIITa₂O₇]^- layers.
• X-ray absorption fine structure (XAFS) and extended XAFS (EXAFS) analysis for oxidation state and atomic arrangement determination.
• Density functional theory (DFT) calculations for framework structure simulation.

Main Results:

• Successfully synthesized charge-neutral [Ce^IVTa₂O₇] layers with tetravalent cerium (Ce).
• Observed decreased near-infrared (NIR) absorption in charge-neutral layers due to the disappearance of Ce 4f electrons.
• Demonstrated chemical reduction of [Ce^IVTa₂O₇] back to [Ce^IIITa₂O₇]^- and redox activity of the anionic layers.

Conclusions:

• The development of "charge-neutral" perovskite layers offers a new pathway for material design.
• Systematic tuning of electronic structure through redox control of cerium generates unique material features.
• This approach holds potential for creating innovative functional materials based on perovskite structures.