10.1021/acs.nanolett.9b01945.s001 F. Hu F. Hu M. Kim M. Kim Y. Zhang Y. Zhang Y. Luan Y. Luan K. M. Ho K. M. Ho Y. Shi Y. Shi C. Z. Wang C. Z. Wang X. Wang X. Wang Z. Fei Z. Fei Tailor Plasmons in Pentacene/Graphene Heterostructures with Interlayer Electron Transfer American Chemical Society 2019 interlayer couplings pentacene layers graphene plasmons tunneling-type electron transfer nanoplasmonic study novel properties thickness dependence surface plasmons IR DFT plasmon wavelength declines nano-optical phenomena vdW heterostructures novel vdW heterostructures pentacene thickness Interlayer Electron Transfer van der Waals Dirac Fermions Tailor Plasmons 2019-08-13 20:43:36 Journal contribution https://acs.figshare.com/articles/journal_contribution/Tailor_Plasmons_in_Pentacene_Graphene_Heterostructures_with_Interlayer_Electron_Transfer/9596183 van der Waals (vdW) heterostructures, which are produced by the precise assemblies of varieties of two-dimensional (2D) materials, have demonstrated many novel properties and functionalities. Here we report a nanoplasmonic study of vdW heterostructures that were produced by depositing ordered molecular layers of pentacene on top of graphene. We find through nanoinfrared (IR) imaging that surface plasmons formed due to the collective oscillations of Dirac Fermions in graphene are highly sensitive to the adjacent pentacene layers. In particular, the plasmon wavelength declines systematically but nonlinearly with increasing pentacene thickness. Further analysis and density functional theory (DFT) calculations indicate that the observed peculiar thickness dependence is mainly due to the tunneling-type electron transfer from pentacene to graphene. Our work unveils a new method for tailoring graphene plasmons and deepens our understanding of the intriguing nano-optical phenomena due to interlayer couplings in novel vdW heterostructures.