Morphological Study of a Self-Organized Corrole Film on a Gold Crystal, both in Solution and after Solvent Evaporation

The morphology ofthe film created by the aggregation of corrolemolecules from ethanol solution onto the surface of gold substratewas studied by scanning tunneling microscopy both: (i) in situ, namelyin quasi-equilibrium (wet sample), and (ii) ex situ, i.e., removingthe substrate from the fluid cell and leaving the residual amountof solution on the substrate to desiccate (dry sample). Despite thedifferent conditions, the morphology of the corrole overlayer formedon the film of molecules is reminiscent, in both cases, of the leopardskin; the speckles are actually areas where the molecularoverlayer of flat molecules is not completed. We quantitatively comparedthese two similar morphologies by studying the power spectral densityof the images, the fractal dimension D (P) of the hole perimeters, and the cumulative distribution functionof the hole areas. We found that the last layer of both films, inspite of very different formation conditions, differed from each otheronly by a scale factor.

Automated summary

The morphology of films formed by corrolemolecules from ethanol solution on gold substrate was examined using scanning tunneling microscopy both in situ (wet sample) and ex situ (dry sample). Despite different conditions, the morphology of the corrole overlayer on the film resembles a leopard skin in both cases, where the speckles represent incomplete coverage by flat molecules. Quantitative analysis of the images revealed that the last layer of both films only differed by a scale factor despite the diverse formation conditions.