Photoluminescence quenching in mixed-dimensional heterostructures from non-covalent functionalization of monolayer WSe<sub>2</sub>via aryl diazonium chemistry
POSTER
Abstract
Monolayer WSe2 is an important member of the 2D layered materials family due to its valley physics and excitonic properties with potential applications in quantum optoelectronics. Chemical functionalization of monolayer WSe2 has been performed with nitrobenzenediazonium (4-NBD), resulting in surface functionalization with nitrophenyl oligomers that induces hole doping of the monolayer. Here, we discuss the optical properties of 4-NBD-treated WSe2 at the limit of full coverage of the nitrophenyl oligomers. In ambient conditions, we observe strong photoluminescence (PL) quenching and redshifting. Moreover, the PL at low temperature shows a nearly complete quenching of the exciton fine structures beyond the neutral exciton. This quenching effect is reversible upon oligomer removal and can be attributed to processes beyond hole doping. X-ray photoelectron spectroscopy reveals that the functionalization is non-covalent, and further elucidates the mixed-dimensional heterojunction formation that contributes to PL quenching in a manner consistent with first-principles calculations. Overall, these results demonstrate that diazonium functionalization is an effective pathway for modifying the optical properties of monolayer WSe2.
Presenters
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Iqbal B Utama
- Northwestern University