Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 49: Metal substrates: Adsorption of organic / bio molecules VI

O 49.9: Talk

Wednesday, March 16, 2011, 17:00–17:15, PHY C213

Assembly and manipulation of rotatable cerium-porphyrinato sandwich complexes on a surface — •Saranyan Vijayaraghavan¹, David Ecija¹, Willi Auwärter¹, Knud Seufert¹, Felix Bischoff¹, Kentaro Tashiro², and Johannes V. Barth¹ — ¹Physik Department, E20 Technische Universität München, Garching, Germany — ²National Institute for Materials Science (NIMS) ,1-1 Namiki, Tsukuba 305-0044, Japan

The characterization and engineering of molecular nanostructures on surfaces is of great interest, especially the development of metal-directed assembly protocols with suitable linkers and metal atoms combined on well-defined surfaces. Porphyrin molecules are ideal building blocks for these surface anchored nanostructures. Particularly interesting are tetrapyrrole-derived sandwich compounds comprising rare-earth metal centres. Here we report a novel route to synthesize such Bis(porphyrinato)cerium double-deckers (Ce(TPP)2) and Tris(porphyrinato) cerium triple-deckers (Ce2(TPP)3 directly on a Ag(111) surface under UHV conditions by exposing a porphyrin precursor layer to a beam of Ce atoms. The double and triple-decker compounds are studied by scanning tunneling microscopy (STM) topographic measurements, including a comparison with Ce(TPP)2 layers generated by molecular beam epitaxy. Moreover, we address the motion of double- and triple-decker moieties in specific environments: the top porphyrin of each molecular species can be rotated by STM manipulation. Such complexes can have important applications like single molecule magnets or field effect transistors.