Is there a method to find the coverage (in terms of monolayer) of organic molecules on metals surfaces? I am dosing my molecule on a Cu(110) surface with different deposition times and I am interested in finding the time corresponding to a monolayer coverage.
Dear Paul,
One way of doing it would be to perform Temperature-Programmed Desorption of different coverages of your organic molecules. The monolayer coverage would be visible on your TPD traces by the transition between a regime with coincident maximum temperature (1st order desorption, sub-monolayer) and a regime with coincident leading edges (0th order desorption, multilayer).
This would enable you to determine the exposure (in terms of time x pressure increase in your chamber) equivalent to a monolayer coverage, assuming that you have a layer-by-layer deposition of your organics on the substrate.
Best wishes
TPD, as Jérôme Lasne suggested, is indeed the right way. Here are two examples of this method including the coverage dependence:
Article Interaction of C 60 with Carbon Nanotubes and Graphite
Article A TPD-based determination of the graphite interlayer cohesion energy
Otherwise you can also perform (lengthy) AFM studies and check at which point a saturation is reached.
Are you referring to grafting density? Molecules per unit area?
Dear Paul Schweer in addition to the expert answers provided by Jérôme Lasne and Jürgen Weippert (I do not call myself an expert in this field) I would like to suggest to you the following potentially useful article:
Determining Surface Coverage of Self-Assembled Monolayers on Gold Electrodes
Article Determining Surface Coverage of Self-Assembled Monolayers on...
This paper has been posted by the author as public full text on RG. Thus is can be freely downloaded as pdf file.
Good luck with your work and best wishes!
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