In this paper, we report the self-assembly, electrical characterization, and surface modification of dithiolated phenylene-ethynylene oligomer monolayers on a Au(111) surface. The self-assembly was accomplished by thiol bonding the molecules from solution to a Au(111) surface. We have confirmed the formation of self-assembled monolayers by scanning tunneling microscopy (STM) and optical ellipsometry, and have studied the kinetics of film growth. We suggest that self-assembled phenylene ethynylene oligomers on Au(111) surfaces grow as thiols rather than as thiolates. Using low-temperature STM, we collected local current-voltage spectra showing negative differential resistance at 6 K.
Walzer, K., Marx, E., Greenham, N. C., Less, R. J., Raithby, P. R., & Stokbro, K. (2004). Scanning tunneling microscopy of self-assembled phenylene ethynylene oligomers on Au(111) substrates. Journal of the American Chemical Society, 126(4), 1229-1234. https://doi.org/10.1021/ja036771v