Ultrathin WO 3 Bilayer on Ag(100): A Model for the Structure of 2D WO 3 Nanosheets

NEGREIROS, F. R.; MOHAMMADI, M.; SURNEV, S.; OBERMÜLLER, TH.; FORTUNELLI, A.; BLATNIK, M.; NETZER, F. P.

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2019 vol. 123 p. 27584 - 27593

1932-7447

Two-dimensional (2D) WO3 nanosheets exhibit a range of novel properties and functionalitiesthat render them attractive for advanced nanotechnologies. However, at the ultimate 2D limitof single ? layer thickness the structural properties of WO3 are unclear. Here we fabricated,using MBE techniques, a crystalline 2D WO3 overlayer on a Ag(100) surface and unveil itsgeometric, electronic and vibrational structure via a combination of state-of-the-artexperimental (microscopic and spectroscopic) and computational techniques. The 2D WO3phase forms a bilayer with staggered arrangement of WO6 octahedra, linked together by cornerand edge sharing, which is significantly different from the cubic and monoclinic WO3 bulkstructures, but resembles a bilayer of the -MoO3 layered bulk lattice. Such 2D WO3 bilayeron Ag(100) is a robust non-polar structure, which is incommensurate in various rotationalorientations, weakly coupled to the metal substrate, and according to the density functionaltheory (DFT) calculations should survive as a stable free-standing layer, i.e. as a nanosheet.