[3Ea01-05] Photo-related scanning probe microscopy: MHz to X-ray: Probe Microscopy Division's Session

[3Ea05] Photon-to-electron conversion in a single molecule investigated by Photon-STM

*Miyabi Imai-Imada^1,2 (1. SISL RIKEN, 2. JST PRESTO)

Photoinduced electron transfer (PET) from an excited molecule is central in energy conversion processes. To deepen understanding of this process, microscopic techniques for photocurrent measurements have been developed. However, the spatial resolution has still not been enough to resolve individual molecules, so the fundamentals of PET remain elusive. In this study, we report atomic-scale visualization of photocurrent channels through the molecular orbitals of a single free-base phthalocyanine (FBPc) molecule using a scanning tunnelling microscope (STM) combined with a tuneable laser. PET from the single FBPc molecule in the first excited state was distinctly detected via the photoinduced tunnelling current through the STM tip. Depending on the applied bias voltage, not only the direction but also the spatial distribution of the photocurrent changes markedly. The detailed mechanism of photocurrent generation will be discussed in the presentation.