Tunneling Electron Induced Fluorescence from Single Porphyrin Molecules Decoupled by Striped-Phase Octanethiol Self-assembled Monolayer

We investigate tunneling electron induced luminescence from isolated single porphyrin molecules that are decoupled by striped-phase self-assembledmonolayer of octanethiol from the underneath Au(111) substrate. Intrinsic single-moleculeelectroluminescence has been realized by such decoupling at both bias polarities. The photon emission intensity acquired from the molecular lobe is found stronger than that from the molecular center. These results provide useful information on the understanding of electroluminescent behavior and mechanism in molecular tunnel junctions.