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Functional Graphene Nanomaterials

The exponentially increasing demand for ever smaller, faster, and more energy efficient electronic devices represents a monumental challenge to the development of advanced functional materials for post-silicon technology. Traditionally, device architectures based on inorganic semiconductors are fabricated using a top-down approach; their performance is inherently limited by the spatial resolution of photolithographic techniques. In our group, we pursue a diametrically opposite strategy. Our design of a new generation of high-performance electronic materials relies on a modular bottom-up strategy that provides unprecedented access to e.g. highly tunable semiconducting or metallic band structures, 1D and 2D magnetic spin chains, or rationally engineered topological phases. Throughout our research we strive to understand, control, and harness the exceptional properties emerging from quantum confinement effects in nanoscale materials by pursuing a highly integrated multidisciplinary research approach ranging from molecular design, organic synthesis, all the way to atomically resolved imaging and spectroscopy using ultra high vacuum (UHV) low temperature (4 K) scanning probe microscopy (SPM) techniques.

Key Publications

"Topological Band Engineering of Graphene Nanoribbons" Rizzo, D. J.; Veber, G.; Cao, T.; Bronner, C.; Chen, T.; Zhao, F.; Rodriguez, H.; Louie, S. G.; Crommie, M. F.; Fischer, F. R. Nature 2018, 560, 204-206.
DOI: 10.1038/s41586-018-0376-8

"Hierarchical On-Surface Synthesis of Graphene Nanoribbon Heterojunctions" Bronner. C.; Durr, R. A.; Rizzo, D. J.; Lee, Y.-L.; Marangoni, T.; Kalayjian, A. M.; Rodriguez, H.; Zhao, W.; Louie, S. G.; Fischer, F. R.; Crommie, M. F. ACS Nano 2018, 12, 2193-2200.
DOI: 10.1021/acsnano.7b08658

"Orbitally Matched Edge-Doping in Graphene Nanoribbons" Durr, R. A.; Haberer, D.; Lee, Y.-L.; Blackwell, R.; Kalayjian, A. M.; Marangoni, T.; Ihm, J.; Louie, S. G.; Fischer, F. R. J. Am. Chem. Soc. 2018, 140, 807–813.
DOI: 10.1021/jacs.7b11886

"Short-Channel Field Effect Transistors with 9-atom and 13-atom Wide Graphene Nanoribbons"Llinas, J.; Fairbrother, A.; Barin, G.; Shi, W.; Lee, K.; Wu, S.; Choi, B. Y.; Braganza, R.; Lear, J.; Kau, N.; Choi, W.; Chen, C.; Pedramrazi, Z.; Dumslaff, T.; Narita, A.; Feng, X.; Müllen, K.; Fischer, F.; Zettl, A.; Ruffieux, P.; Yablonovitch, E.; Crommie, M.; Fasel, R.; Bokor, J. Nat. Commun. 2017, 8, 633.
DOI: 10.1038/s41467-017-00734-x

"Atomically Precise Graphene Nanoribbon Heterojunctions from a Single Molecular Precursor" Nguyen, G. D.; Tsai, H.-Z.; Omrani, A. A.; Marangoni, T.; Wu, M.; Rizzo, D. J.; Rodgers, G.; Cloke, R.R.; Durr, R.A.; Sakai, Y.; Liou, F.; Aikawa, A. S.; Chelikowsky, J. R.; Louie, S. G.; Fischer, F. R.; Crommie, M. F. Nature Nanotechnology 2017, 12, 1077-1082.
DOI: 10.1038/nnano.2017.155

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Scanned Probe Microscopy

Scanned probe microscopy (SPM) has been a key tool for understanding atomic-scale processes at surfaces since its invention over 30 years ago. Recent dramatic advances in atomic force microscopy (AFM) and scanning tunneling microscopy (STM) have demonstrated that the controlled attachment of a single atom or molecule to the apex of an STM or AFM tip can result in an extraordinary enhancement of spatial resolution, the ability to perform unprecedented imaging of chemical structures, even reveal intricate details of the intramolecular bond order. These significant developments have spawned new tools and methods to visualize atomic scale chemical processes that could never before be studied, including reaction products whose structure could not be resolved by any other currently available technique. A common theme for all of these recent advances is that they involve careful engineering of the microscopic energy landscape that arises from tip-surface interactions. Our group is dedicated to advancing both the imaging technology itself (i.e. resolving the structure of nonplanar natural products or biological samples) and to explore reaction pathways unique to molecule-surface interfaces that provide access to elusive chemical structures and mechanisms.

Key Publications

"Imaging Single-Molecule Reaction Intermediates Stabilized by Surface Dissipation and Entropy" Riss, A.; Perez Paz, A.; Wickenburg, S.; Tsai, H.-Z.; de Oteyza, D. G.; Bradley, A. J.; Ugeda, M. M.; Gorman, P.; Jung, H. S.; Crommie, M.; Rubio, A.; Fischer, F. R. Nat. Chem. 2016, 7, 678-683.
DOI: 10.1038/nchem.2506

"Closing the Nanographene Gap: Surface-Assisted Synthesis of Peripentacene from 6,6’-Bipentacene Precursors" Rogers, C.; Chen, C.; Pedramrazi, Z.; Omrani, A. A.; Tsai, H.-Z.; Jung, H. S.; Lin, S.; Crommie, M. F.; Fischer, F. R. Angew. Chem. Int. Ed. 2015, 54, 15143-15146.
DOI: 10.1002/anie.201507104

"Local Electronic and Chemical Structure of Oligo-acetylene Derivatives Formed Through Radical Cyclizations at a Surface" Riss, A.; Wickenburg, S.; Gorman, P. Tan, l. Z.; Tsai, H.-Z.; de Oteyza, D. G.; Chen, Y.-C.; Bradley, A. J. Ugeda, M. M.; Etkin, G.; Louie, S. G.; Fischer, F. R.; Crommie, M. F. NANO Letters 2014, 14, 2251-2255.
DOI: 10.1021/nl403791q

"Direct Imaging of Covalent Bond Structure in Single-Molecule Chemical Reactions" de Oteyza, D. G.; Gorman, P.; Chen, Y.-C.; Wickenburg, S.; Riss, A.; Mowbray, D. J.; Etkin, G.; Pedramrazi, Z.; Tsai, H.-Z.; Rubio, A.; Crommie, M. F.; Fischer, F. R. Science 2013, 340, 1434-1437.
DOI: 10.1126/science.1238187

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Catalysis and Functional Polymers

Controlling the intra- and intermolecular forces directing the self-assembly of biological polymers at the micro- and macroscopic scale into functional hierarchical macromolecules, such as enzymes, chromosomes, or polysaccharides, is of paramount importance for all living organisms. The diversity both in architecture and function emerging from these complex but finely tuned arrangements of building blocks ranges from molecular machinery, data and energy storage, to structural support at the nanometer scale. While synthetic polymers have been adapted to almost every aspect of our industrialized culture, their performance and structural diversity still falls short when compared to their biological analogues.
In an effort to address these shortcomings our group is pioneering the development of new polymerization catalysts and techniques, e.g. living ring-opening alkyne metathesis polymerization (ROAMP), that provide access to functional conjugated polymers with predetermined monomer sequences, functional end groups, and programmable secondary and tertiary structure.

Key Publications

"Regioselective Termination Reagents for Ring-Opening Alkyne Metathesis Polymerization" Jeong, H.; von Kugelgen, S.; Bellone, D. E.; Fischer, F. R. J. Am. Chem. Soc. 2017, 139, 15509-15514.
DOI: 10.1021/jacs.7b09390

"Regioselective Carbyne Transfer to Ring-Opening Alkyne Metathesis Initiators Gives Access to Telechelic Polymers" von Kugelgen, S.; Sifri, R.; Bellone, D.; Fischer, F. R. J. Am. Chem. Soc. 2017, 139, 7577-7585.
DOI: 10.1021/jacs.7b02225

"Initiator Control of Conjugated Polymer Topology in Ring-Opening Alkyne Metathesis Polymerization" von Kugelgen, S.; Bellone, D.; Cloke, R. R.; Perkins, W.; Fischer, F. R. J. Am. Chem. Soc. 2016, 138, 6234–6239.
DOI: 10.1021/jacs.6b02422

"Highly Selective Molybdenum ONO Pincer Complex Initiates the Living Ring-Opening Metathesis Polymerization of Strained Alkynes with Exceptionally Low Polydispersity Indices" Bellone, D.E.; Bours, J.; Menke, E. H.; Fischer, F. R. J. Am. Chem. Soc. 2015, 137, 850-856.
DOI: 10.1021/ja510919v

© 2015, Felix Fischer