Laboratory for Surface Modification (LSM)

Seminars Archives

June 2017 | August 2017 | September 2017

Tuesday, August 01, 2017
In situ metalation of porphyrins on metals and oxides
Hans-Peter Steinrueck
Lehrstuhl für Physikalische Chemie II
Universität Erlangen-Nürnberg, Germany
12:00 Noon CHEM 260

Chemical reactions on surfaces can be followed in detail using X-ray photoelectron spectroscopy (XPS or ESCA), in particular in combination with scanning tunneling microscopy (STM). From the XPS binding energies of the adsorbate and substrate core levels, detailed information on the chemical composition, chemical state (e.g. oxidation state), adsorption sites, but also on the photoemission process itself can be derived. STM provides information on surface order and intramolecular conformation but also on the chemical state. Based on the understanding obtained for simple adsorbate systems, now complex molecular systems can be studied in great detail. One specifically interesting group of materials are metalloporphyrins. These metallotetrapyrrole complexes are versatile functional building blocks in many biological and biochemical processes. Moreover, there are several examples where such molecules were utilized in technical applications, retaining their highly functional nature within an inorganic framework. Examples include gas sensors, solar cells and catalysts. In this presentation the surface chemistry of porphyrins on metal and oxide substrates will be addressed. Specific topics are the interplay between porphyrin-substrate and porphyrin-porphyrin interactions, the role of the substrate, surface diffusion, and the synthesis of metalloporphyrin monolayers by direct metalation of free base porphyrins.[1-8]

[1] S. Ditze, M. Stark, M. Drost, F. Buchner, H.-P. Steinrück, H. Marbach, Activation energy for the self-metalation reaction of 2H-tetraphenylporphyrin on Cu(111), Angew. Chem. Int. Edition 51 (2012) 10898.
[2] M. Röckert, M. Franke, Q. Tariq, S. Ditze, M. Stark, P. Uffinger, D. Wechsler, U. Singh, J. Xiao, H. Marbach, H.-P. Steinrück, O. Lytken, Coverage- and Temperature-dependent Metalation and Dehydrogenation of Tetraphenylporphyrin (2HTPP) on Cu(111), Chem. Eur. J. 20 (2014) 8948.
[3] M. Stark, S. Ditze, M. Lepper, L. Zhang, H. Schlott, F. Buchner, M. Röckert, M. Chen, O. Lytken, H.-P.Steinrück, and H. Marbach, Massive conformational changes during thermally induced self-metalation of 2H-Tetrakis-(3,5-di-tert-butyl)-phenyl­porphyrin on Cu(111), Chem. Commun. 50 (2014) 10225.
[4] M. Röckert, M. Franke, Q. Tariq, H.-P. Steinrück and O. Lytken, Evidence for a Precursor Adcomplex During the Metalation of 2HTPP with Iron on Ag(100), Chem. Phys. Lett. 635 (2015) 60.
Monday, August 07, 2017
Color Printing as a New Direction in Plasmonic Applications
Dr. Sergey Novikov
Centre for Nano Optics
Institute of Technology and Innovation
University of Southern Denmark
1:30 PM CCR 201

Plasmonic colours are structural colours that emerge from resonant interactions between light and metallic nanostructures.The engineering of plasmonic colours is a promising, rapidly emerging research field that could have a large technological impact. Colours and decorations are important for the perception and identification of both natural and artificial objects. Artificial structural colour surfaces can be based on resonances in all-dielectric structures or on localized plasmon resonances in metallodielectric architectures. Over the past decade, the field of plasmonics has seen the opening of numerous research and application directions. With the most recent developments in terms of materials and fabrication techniques in mind, it could be anticipate that plasmonic colour technologies will rapidly approach real applications, ranging from surface decoration, digital displays and molecular sensing to optical security devices and durable optical data storage. Most remarkable is the opportunity for intriguingly high colour printing resolution and the prospect for plasmonic colour laser printing at the post-processing stage. In this talk will be discuss some recent advances in the production of plasmonic colours that have emerged owing to rapid developments in nanoplasmonics design and in nanofabrication.

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