University of California, Riverside

Department of Chemistry



Faculty


 

 

Ludwig Bartels
Professor of Chemistry CFM in Elec. & Mech. Eng. and Physics

 

Freie Universitat, Berlin, Germany - Vordiplom (1991)
Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany - Diploma Thesis (1995)
Freie Universitat Berlin, Germany - Doctor Rerum Naturalis
Paul-Drude-Institute for Solid State Electronics, Berlin, Germany - Postdoc. Fellow (1997-1998)
Columbia University, New York, USA - Postdoc. Fellow (1998-2000)

Office: 124 Pierce Annex
Phone O/L: (951) 827-2041/2057
Email: ludwig.bartels@ucr.edu
Research Area: Physical Chemistry, Analytical Chemistry, Computational Chemistry, Materials Chemistry
Group Site

Research Interest


Research in the Bartels Lab addresses three different areas of surface chemistry, physics and materials science: the growth and properties of MoS2 and other metal dichalcogenides monolayers; the processes underlying ordering and self-assembly of molecular layers at metal surfaces; and the control of molecular motion at surface aiming at the development of molecular machines.


MoS2 and other metal dichalcogenides have recently attracted a lot of attention, because even when they are only a single layer thick they are stable in air and natively semiconducting. Through research in graphene, techniques for testing and processing such materials have been developed. But graphene is a conductor, thus it cannot be directly used for transistors, solar cells and many other electronic/electrochemical applications where semiconductivity is required. Work in the Bartels group supports ongoing research efforts in metal dichalcogenies by growing single layer films of MoS2 and many related materials. We also explore their optical (excitonic) properties, because excitons in such films are important for optical/solar applications, and they also pose a facile means of obtaining insight into the electronic properties of the materials.

While we can grow films on wafers in furnaces for a variety of electronic investigations, the explorations of the catalytic properties (and of materials processing in general) we conduct in vacuum. We use variable temperature scanning tunneling microscopy (STM) to get atomic scale insight into the structure and the binding of reactants to the surface of MoS2 and other molybdenum-sulfur compounds. Using photoelectron spectroscopy as well as thermal desorption we obtain information on their composition and reactivity.

The investigation of molecular films at metals surfaces has revealed a host of novel physical and chemical phenomena: molecules can form coordination compounds at surfaces including ones with anionic (negatively-charged) metal centers typically not found in the solution phase; they can form networks utilizing hydrogen bonds involving, for instance, hydrogen atoms attached to aromatic rings, which in the solution phase are too weak to have structure-determining power; the arrangement of molecules in honeycombs can cause coalescence of electrons of the substrate into favorable quantum dots, thus driving the aggregation of the network in the first place. We constantly explore surface coverage by low-temperature STM to find new phenomena and understand them in physical detail.

The control of molecular motion at surfaces has been our focus for a long time. We found and explored a range of substituted acenes (e.g., anthraquinone, dithio-anthracene) which can run across a flat, high-symmetry surfaces as if they were moving on straight tracks by means of sequential motion of their substrate linkers. Using this class of molecules, we explored the transport of cargo across surfaces, fundamental aspects of tunneling in the crossing of reaction barriers, microscopic reversibility and a range of other chemical themes. This work was widely reported on in general publications from the Financial Times to Scientific American.  


Graduate Student Opportunities

About 10 graduate students work currently in the Bartels lab. Their background and major are in Chemistry, Physics, Materials Science & Engineering and Electrical Engineering. Their interdisciplinary interaction and expertise allow us to approach our research goals in a comprehensive way from instrument development, materials growth, analysis and characterization all the way to theoretical modeling in our 150 core computational cluster. Several of Bartels group graduate students won prestigious fellowships, such as NSF graduate research or AGEP fellowships, NRC fellowships, etc. Graduates of the Bartels group typically either pursue careers at equipment manufacturers for the semiconductor industry (Veeco, Applied Materials, etc.) or in academia/national labs (several attained faculty positions). Interested? Stop by my office any time or send me an email!

Undergraduate Student Opportunities

About 10 undergraduate students work currently in the Bartels lab. They come from different majors and perform different tasks ranging from programming and computational modeling of surface reactions to the growth and characterization of MoS2 and related materials. Undergraduate students who gained experience in the Bartels lab over the academic year often work in the lab over the summer funded by fellowships or hired as lab assistants. If you are interested, just stop by my office any time and/or speak to one of the current undergraduate or graduate student researchers.

Awards

Selected Publications

 

More Information 

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Department Information

Department of Chemistry
Chemical Sciences
501 Big Springs Road

Tel: (951) 827-3789 (Chair's Assistant)
Fax: (951) 827-2435 (confidential)
E-mail: jingsong.zhang@ucr.edu

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