Molecular Doping of MoS2 with N-Heterocyclic Carbenes: A Raman Study of Interfacial Charge Transfer
Abstract
We demonstrate efficient electron doping of exfoliated MoS2 through the deposition of N-heterocyclic carbene (NHC) molecules onto its surface. Raman spectroscopy reveals a pronounced softening of the optical A1g phonon mode after NHC deposition, consistent with electron transfer from the NHC molecules to the MoS2 layers. The largest phonon-energy shifts are observed in monolayer and bilayer flakes whereas changes in bulk-like MoS2 are negligible, indicating that the doping efficiency depends on the number of layers. This thickness dependence highlights the dominant role of interfacial charge transfer at the NHC/MoS2 interface. Quantitative analysis of the Raman modes of as-exfoliated and NHC-covered MoS2, together with comparison with literature values, allows us to estimate an increase in the two-dimensional electron density of about two-orders of magnitude in MoS2 mono- and bilayers. These results demonstrate that NHC-based surface deposition is a promising approach for chemically tuning the carrier density of semiconducting transition-metal dichalcogenides and provide a potential route toward molecularly tunable two-dimensional electronic devices, in which, analogous to modulation doping, the donors reside outside the semiconductor lattice.
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BibTeX
@misc{senkic2026molecular,
title = {{Molecular Doping of MoS$_2$ with N-Heterocyclic Carbenes: A Raman Study of Interfacial Charge Transfer}},
author = {Ana Senkić and Arne Nalop and Xenia Sieverding and Ariane Ufer and Sebastian Roling and Frank Glorius and Ursula Wurstbauer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.24769},
eprint = {2610.24769},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.24769},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Molecular Doping of MoS_2 with N-Heterocyclic Carbenes: A Raman Study of Interfacial Charge Transfer
AU - Ana Senkić
AU - Arne Nalop
AU - Xenia Sieverding
AU - Ariane Ufer
AU - Sebastian Roling
AU - Frank Glorius
AU - Ursula Wurstbauer
PY - 2026
DA - 2026/10/17
PB - arXiv
DO - 10.48550/arxiv.2610.24769
UR - https://arxiv.org/abs/2610.24769
AB - We demonstrate efficient electron doping of exfoliated MoS_2 through the deposition of N-heterocyclic carbene (NHC) molecules onto its surface. Raman spectroscopy reveals a pronounced softening of the optical A_1g phonon mode after NHC deposition, consistent with electron transfer from the NHC molecules to the MoS_2 layers. The largest phonon-energy shifts are observed in monolayer and bilayer flakes whereas changes in bulk-like MoS_2 are negligible, indicating that the doping efficiency depends on the number of layers. This thickness dependence highlights the dominant role of interfacial charge transfer at the NHC/MoS_2 interface. Quantitative analysis of the Raman modes of as-exfoliated and NHC-covered MoS_2, together with comparison with literature values, allows us to estimate an increase in the two-dimensional electron density of about two-orders of magnitude in MoS_2 mono- and bilayers. These results demonstrate that NHC-based surface deposition is a promising approach for chemically tuning the carrier density of semiconducting transition-metal dichalcogenides and provide a potential route toward molecularly tunable two-dimensional electronic devices, in which, analogous to modulation doping, the donors reside outside the semiconductor lattice.
ER -