Special CPM Seminar

Electronic landscapes of organic semiconductor nanostructures: mapping states for charge transfer at sub-molecular scales using pixel-by-pixel STS

Sarah Burke

Dept. of Physics & Astronomy / Dept. of Chemistry
University of British Columbia

Applications in organic electronics and catalysis rely on inter- and intra-molecular energy transfer that is driven by the spatial distribution of electronic states and their energy level alignment. I will discuss two model molecular systems we have been investigating using Scanning Tunnelling Microscopy (STM) and Spectroscopy (STS) in a spectroscopic mapping mode that allows us to visualize the electronic states across nanoscale structures. Small clusters of a prototype organic semiconductor, PTCDA, showed strong shifts at the boundaries of islands which we attribute predominantly to the local polarization environment provided by the neighbouring molecules. On-surface synthesized metal-organic coodination polymers based on Fe-terpyridine linkages show that the electronic structure of molecular complexes can be carried over to surface-bound structures, offering unique opportunities for control. In each of these examples, the sub-molecular resolution spectroscopy yields high resolution energetic and spatial information that can be used to understand the local electronic landscape and directly relate this to the local molecular structure.