Synthesis and X-ray absorption spectroscopic analysis of exfoliated perovskite oxynitride nanosheets obtained from LiLaTa2O6.15N0.57 precursor

Abstract

Layered perovskite oxynitride LiLaTa2O6.15N0.57 with Dion-Jacobson phase was successfully exfoliated into colloidal suspension by using proton-exchange reaction and followed intercalation of ethylamine and tetrabutylammonium ion. According to the X-ray diffraction pattern, a basal spacing of the layered perovskite oxynitride concomitantly increased as the intercalation reaction with bulky cations proceeded. Transmission electron microscopy and atomic force microscopy analysis indicated that the exfoliated perovskite oxynitride was composed of single-layered and multi-stacked nanoplatelets. UV-vis diffuse reflectance showed that the self-reassembled perovskite oxynitride nanosheet also had characteristic absorption in a visible range, revealing that visible light harvesting property of the perovskite oxynitride maintained even after exfoliation and subsequent reassembling reaction. Extended X-ray absorption fine structure (EXAFS) analysis of samples clearly showed that structural disorder upon intercalation reaction resulted in damping of EXAFS oscillation, suggesting nanosized feature of the exfoliated nanosheet.