Oligo(phenylene ethynylene) used in these UHV self-assembly experiments.
(a) Ellipsometry-determined molecular layer thicknesses vs temperature for samples exposed for . (b) Thicknesses vs time for samples exposed at a constant temperature of . The line at is the approximate expected molecular thickness for the thiolate chemisorbed on Au.
OPE samples both unrinsed and rinsed with THF. The line at is the approximate expected molecular thickness for the thiolate chemisorbed on Au.
Thickness vs exposure time for a constant source temperature of . This figure shows that the expected thickness for a monolayer (approximately ) was achieved for exposures of . Note: This figure is for samples assembled using an OPE source that was reloaded with molecules after samples were assembled for Figs. 2 and 3. The line at is the approximate expected molecular thickness for the thiolate chemisorbed on Au.
(a) XPS of a thick sample that showed bound sulfur peaks. (b) XPS of a sample thicker than that showed both the bound and the unbound sulfur peaks.
XPS survey spectrum of a thick sample showing only peaks due to the carbon in the OPEs, the Au substrate, and the sulfur end group.
STM image of a sample of the OPE molecules on gold using a Molecular Imaging PicoPlus with tip. “Striping” in image is indicative of ordering of the monolayer.
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