Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 19: Nanostructures at surfaces: Arrays

O 19.4: Vortrag

Dienstag, 24. März 2009, 11:15–11:30, SCH A215

Substrate effect on supramolecular self-assembly: from semiconductors to metals — •Takayuki Suzuki¹, Theresa Lutz¹, Dietmar Payer¹, Nian Lin^1,2, Steven Tait^1,3, Giovanni Costantini^1,4, and Klaus Lern^1,5 — ¹MPI for Solid State Res., Heisenbergstr. 1, 70569 Stutgart — ²Dept. of Phys., The Hong Kong Univ. of Sci. Technol., Clear Water Bay, Kowloon, HK — ³Dept. of Chem., Indiana Univ., Bloomington, 47405 IN — ⁴Dept. of Chem., Univ. of warwick, Coventry, CV4 7AL — ⁵IPN, EPFL, 1015 Lausanne

Terephthalic acid (TPA) deposited on Si(111)-7×7, Si(111)-( 3)^1/×( 3)^1/-Ag and Ag(111) has been studied as a model system to understand how much passivated semiconductor surfaces differ from semiconductor and metal surfaces in respect to supramolecular self-assembly. By scanning tunneling microscopy it is found that TPA molecules do not form any ordered supramolecular structure on the pristine semiconductor surface, due to a strong molecule-substrate interaction. On the contrary, TPA has a weaker interaction with Si(111)-( 3)^1/×( 3)^1/-Ag, leading to the formation of an ordered supramolecular layer stabilized by carboxyl hydrogen bonds. These structures are very similar to the supramolecular layer of TPA formed on Ag(111), indicating that the two substrates behave similarly in respect to the adsorption of functional organic molecules. However, the deposition of Fe on the TPA layers on Si(111)-( 3)^1/×( 3)^1/-Ag does not induce the formation of metal-organic frameworks which, on the contrary, readily develop on Ag(111). The origins of this difference are probably the particular electronic properties and reactivity of the two substrates.