Scanning tunneling microscopy and photoelectron spectroscopy investigation of the sexithiophene:C60 donor-acceptor nanostructure formation on graphite

Abstract

The organic donor-acceptor nanostructure formation processes of C 60 and -sexithiophene (6T) on graphite are monitored by in situ low-temperature scanning tunneling microscopy and synchrotron-based photoelectron spectroscopy experiments. It is found that the intermolecular interaction between C60 and 6T plays a key role in the formation of organic nanostructures on graphite. Room temperature deposition of C 60 on the 6T monolayer on the weakly interacting graphite substrate results in the coexistence of three energetically stable structural motifs with a well-defined supramolecular arrangement, including C60 zigzag filament, C60 hexagon and C60-pair filament, and hence the formation of C60:6T molecular glass on graphite. Our results show that only the thermally stable C60 zigzag filaments can develop into a long-range ordered two-dimensional C60 zigzag chain array by annealing the system at 350 K. © 2011 American Institute of Physics.