Mixed-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) - MoS 2 heterojunctions using optical absorption and Raman spectroscopy to elucidate M core (M = first row transition metal), MoS 2 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 MoS 2 layer number, ultimately reaching a maximum enhancement factor of 30x relative to SiO 2 substrates. These experimental results, combined with density functional theory (DFT) calculations, indicate strong coupling between nonfrontier MPc orbitals and the MoS 2 band structure as well as charge transfer across the heterojunction interface that varies as a function of the MPc electronic structure.
- charge transfer
- transition metal dichalcogenide
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)