Bandgap Shrinkage and Charge Transfer in 2D Layered SnS2 Doped with V for Photocatalytic Efficiency Improvement
Journal
Small
Journal Volume
18
Journal Issue
2
Date Issued
2022
Author(s)
Abstract
Effects of electronic and atomic structures of V-doped 2D layered SnS2 are studied using X-ray spectroscopy for the development of photocatalytic/photovoltaic applications. Extended X-ray absorption fine structure measurements at V K-edge reveal the presence of V-O and V-S bonds which form the intercalation of tetrahedral O-V-S sites in the van der Waals (vdW) gap of SnS2 layers. X-ray absorption near-edge structure (XANES) reveals not only valence state of V dopant in SnS2 is ≈4+ but also the charge transfer (CT) from V to ligands, supported by V Lα,β resonant inelastic X-ray scattering. These results suggest V doping produces extra interlayer covalent interactions and additional conducting channels, which increase the electronic conductivity and CT. This gives rapid transport of photo-excited electrons and effective carrier separation in layered SnS2. Additionally, valence-band photoemission spectra and S K-edge XANES indicate that the density of states near/at valence-band maximum is shifted to lower binding energy in V-doped SnS2 compare to pristine SnS2 and exhibits band gap shrinkage. These findings support first-principles density functional theory calculations of the interstitially tetrahedral O-V-S site intercalated in the vdW gap, highlighting the CT from V to ligands in V-doped SnS2. © 2021 Wiley-VCH GmbH
SDGs
Other Subjects
Binding energy;Calculations;Charge transfer;Density functional theory;Extended X ray absorption fine structure spectroscopy;IV-VI semiconductors;Ligands;Light absorption;Shrinkage;Tin compounds;Valence bands;Van der Waals forces;X ray absorption;X ray absorption near edge structure spectroscopy;X ray scattering;Band-gap shrinkage;Bandgap shrinkage;Density-functional-theory;Inelastic X-rays scatterings;Photocatalytic efficiency;Resonant inelastic X-ray scattering;V-doped 2d layered SnS 2;Van der Waal;X-ray absorption near-edge structure;X-ray absorptions;Energy gap
Type
journal article