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Processing of giant graphene molecules by soft-landing mass spectrometry


The processability of giant (macro)molecules into ultrapure and highly ordered structures at surfaces is of fundamental importance for studying chemical, physical and biological phenomena, as well as their exploitation as active units in the fabrication of hybrid devices1,2. The possibility of handling larger and larger molecules provides access to increasingly complex functions3,4,5,6. Unfortunately, larger molecules commonly imply lower processability due to either their low solubility in liquid media or the occurrence of thermal cracking during vacuum sublimation. The search for novel strategies to process and characterize giant building blocks is therefore a crucial goal in materials science. Here we describe a new general route to process, at surfaces, extraordinarily large molecules, that is, synthetic nanographenes7, into ultrapure crystalline architectures. Our method relies on the soft-landing of ions8 generated by solvent-free matrix-assisted laser desorption/ionization (MALDI). The nanographenes are transferred to the gas phase, purified and adsorbed at surfaces. Scanning tunnelling microscopy reveals the formation of ordered nanoscale semiconducting supramolecular architectures. The unique flexibility of this approach allows the growth of ultrapure crystalline films of various systems, including organic, inorganic and biological molecules, and therefore it can be of interest for technological applications in the fields of electronics, (bio)catalysis and nanomedicine.

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Figure 1: Setup and model compounds.
Figure 2: Molecular adlayer soft-landed on HOPG.
Figure 3: Schematic diagram of the packing of C42H18.


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We thank T. Jung for enlightening discussions and D. Jones for his comments on the manuscript. We acknowledge financial support from ESF-SONS-BIONICS, the EU through the Marie Curie EST-SUPER (MEST-CT-2004-008128) and the IP-NAIMO (NMP4-CT-2004-500355), as well as Emilia Romagna-Consorzio Spinner (TT-NANOSMILE grant).

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Correspondence to Hans Joachim Räder, Paolo Samorì or Klaus Müllen.

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Räder, H., Rouhanipour, A., Talarico, A. et al. Processing of giant graphene molecules by soft-landing mass spectrometry. Nature Mater 5, 276–280 (2006).

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