nn8b09166_si_001.pdf (1.09 MB)
Electronic Coupling in Metallophthalocyanine–Transition Metal Dichalcogenide Mixed-Dimensional Heterojunctions
journal contribution
posted on 2019-03-08, 00:00 authored by Samuel
H. Amsterdam, Teodor K. Stanev, Qunfei Zhou, Alexander J.-T. Lou, Hadallia Bergeron, Pierre Darancet, Mark C. Hersam, Nathaniel P. Stern, Tobin J. MarksMixed-dimensional
heterojunctions, such as zero-dimensional (0D)
organic molecules deposited on two-dimensional (2D) transition metal
dichalcogenides (TMDCs), often exhibit interfacial effects that enhance
the properties of the individual constituent layers. Here we report
a systematic study of interfacial charge transfer in metallophthalocyanine
(MPc) – MoS2 heterojunctions using optical absorption
and Raman spectroscopy to elucidate M core (M = first row transition
metal), MoS2 layer number, and excitation wavelength effects.
Observed phenomena include the emergence of heterojunction-specific
optical absorption transitions and strong Raman enhancement that depends
on the M identity. In addition, the Raman enhancement is tunable by
excitation laser wavelength and MoS2 layer number, ultimately
reaching a maximum enhancement factor of 30x relative to SiO2 substrates. These experimental results, combined with density functional
theory (DFT) calculations, indicate strong coupling between nonfrontier
MPc orbitals and the MoS2 band structure as well as charge
transfer across the heterojunction interface that varies as a function
of the MPc electronic structure.