Related Experiment Video
Updated: Mar 17, 2026
10:36
Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating
Published on: April 12, 2018
12.1K
Excitonic Effects in Tungsten Disulfide Monolayers on Two-Layer Graphene
Cristina E Giusca1, Ivan Rungger1, Vishal Panchal1
1National Physical Laboratory , Hampton Road, Teddington TW11 0LW, United Kingdom.
ACS Nano
|July 20, 2016
Summary
The number of graphene layers supporting tungsten disulfide (WS2) significantly impacts its light emission. Two-layer graphene enhances WS2 photoluminescence by tenfold compared to one-layer graphene.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Light emission in 2D heterostructures depends on material type, layer number, and stacking.
- Substrate properties can influence the optoelectronic behavior of 2D materials.
Purpose of the Study:
- To investigate the effect of 2D substrate thickness on light emission in WS2/graphene heterostructures.
- To understand how interlayer electronic coupling influences excitonic properties.
Main Methods:
- Fabrication of vertical heterostructures with monolayer WS2 on one- and two-layer epitaxial graphene.
- Characterization of layer-dependent charge transfer and excitonic properties.
Main Results:
- Excitonic properties of WS2 are tunable by the number of supporting graphene layers.
- WS2 on two-layer graphene shows a tenfold increase in photoluminescence compared to WS2 on one-layer graphene.
- Evidence of significant enhancement in photoluminescence response due to substrate engineering.
Conclusions:
- Substrate engineering, specifically the thickness of the 2D substrate, is crucial for modulating light emission in atomically thin heterostructures.
- The number of graphene layers plays a key role in tuning the electronic coupling and excitonic properties of WS2.
Keywords:
ab initio calculationsepitaxial grapheneexcitonic effectsheterostructurestrionstungsten disulfide monolayerwork functionMore Related Videos
Related Concept Videos
04:01VSEPR Theory and the Effect of Lone Pairs
54.0K
Effect of Lone Pairs of Electrons on Molecule Geometry
54.0K
01:30The Electrical Double Layer
106
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
106
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
49.5K
02:42Valence Bond Theory
11.5K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
11.5K
01:28Debye–Huckel–Onsager Conductance Equation
80
The Debye-Hückel-Onsager equation is a cornerstone of physical chemistry, providing a method to determine the molar conductance (Λm) and molar conductance at infinite dilution (Λ°m) for uni-univalent electrolytes.Uni-univalent electrolytes are electrolytes that dissociate in solution to produce one cation with a +1 charge and one anion with a –1 charge per formula unit.This equation addresses two crucial phenomena: the asymmetry effect and the electrophoretic effect.
80
01:27π Electron Effects on Chemical Shift: Overview
1.9K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.9K