Adsorption of NO₂on WSe₂: DFT and photoelectron spectroscopy studies

Abstract

The electronic structure modifications of WSe2 upon NO2-adsorption at room and low temperatures were studied by means of photoelectron spectroscopy. We found only moderate changes in the electronic structure, which are manifested as an upward shift of the WSe2-related bands to the smaller binding energies. The observed effects are modelled within the density functional theory approach, where a small adsorption energy of gas molecules on the surface of WSe2 was deduced. The obtained experimental data are explained as a valence bands polarisation effect, which causes their energy shift depending on the adsorption geometry and the formed dipole moment.

Doping, Contact and Interface Engineering of Two‐Dimensional Layered Transition Metal Dichalcogenides Transistors

“…The adsorbed gas molecules are found to have a doping effect on the host materials. This effect has been demonstrated both theoretically and experimentally . The adsorption process can be classified into physisorption and chemisorption.…”

Electrically-Transduced Chemical Sensors Based on Two-Dimensional Nanomaterials

“…The primary doping (inherent doping) is carried out during the synthesis of the materials by incorporating doping ions or during the chemical or electrochemical preparation processes. 186 In some instances, the doping induced by a 2 orbital of carbon (large π system), defects 153,154 π−π interaction, 155,156 van der Waals, 153 charge transfer 157 black phosphorus p z orbital of P atom 158 charge transfer 98,159,160 Xenes unstable sp 2 orbital, defects 161 charge transfer, 162 dispersive interaction, chemical reaction 163 metals zero-valent metal atom, 164 pre-adsorbed oxygen species 165 charge transfer, chemical reaction TMDCs p orbital of chalcogenide atoms, 166,167 defects 168,169 charge transfer 170 metal oxides pre-adsorbed oxygen species 152,171,172 redox reaction 2D MOFs d orbital of metal node, 173−175 adsorbed water/oxygen charger transfer, coordination, H-bond 176 MXene O, OH, and F on surface, 177,178 van der Waals, H-bond, charge transfer 179 h-BN, g-CN electron deficient π system, 180 defects, 181 absorbed O 2 182 π−π interaction, van der Waals, oxidation reaction proximal analyte can drastically alter the inherent doping levels of the material. The primary doping effect of the material can be minimized or undergo complete deactivation due to analyte−dopant interactions.…”

Theoretical Study of CO Adsorption Interactions with Cr-Doped Tungsten Oxide/Graphene Composites for Gas Sensor Application

“…The g-CrW 2 O 9 and g-CrW 3 O 12 composites show four major peaks, and the peaks shift from 6.367, 7.658, 8.088, and 9.608 eV to 6.197, 7.488, 7.968, and 9.523 eV for the g-CrW 2 O 9 composite, while the shift for the g-CrW 3 O 12 composite is from 6.382, 7.663, 8.098, and 9.623 eV to 6.202, 7.482, 7.918, and 9.528 eV, respectively. From the shift in the peak, it is evident that there is physisorption between CO and the structure of the composites, and this leads to the dipole moment polarization of the upper part of the structure . Thus, it can be deduced that there is physisorption interaction in the deeper orbitals.…”

“…From the shift in the peak, it is evident that there is physisorption between CO and the structure of the composites, and this leads to the dipole moment polarization of the upper part of the structure. 51 Thus, it can be deduced that there is physisorption interaction in the deeper orbitals. The decreasing order of the physisorption interaction is g-W 4 O 12 > CrWO 6 > g-CrW 2 O 9 and g-CrW 3 O 12 > g-W 2 O 6 > g-W 3 O 9 > graphene.…”