Tobin J. Marks, Morrison Professor
Department of Chemistry
Northwestern University

E-mail: t-marks@northwestern.edu
Phone: 847-491-5658

BS, University of Maryland
PhD, Massachusetts Institute of Technology

National Fresenius Award, Phi Lambda Upsilon
American Chemical Society Awards in Polymeric Materials, Organometallic Chemistry, and Inorganic Chemistry Guggenheim Fellow
Member, National Academy of Sciences
Member, American Academy of Arts and Sciences

Research Areas
Nanoscience and nanotechnology research in the Marks group is focused on the rational design, synthesis/fabrication, understanding, and ultimate technological insertion of nanoscopically regular molecule-based structures exhibiting unusual optoelectronic and photonic properties. Science issues concern how very small structural perturbations control the processing and switching of light, the injection of charge across interfaces, electron-hole recombination processes, and the emission or detection of light. Technology issues concern how self-assembly processes can be employed to create devices which shift the frequency of light, modulate light for ultra-high speed/high bandwidth data transmission applications, efficiently emit light for flat panel and microdisplays, and respond to light for ultra-high resolution sensors and detectors. Key collaborations in theory (Ratner), photonics characterization (Ho), film growth (Chang, Wessels), and microstructure (Dravid) are an active part of the programs. In the optoelectronics area, molecular self-assembly processes have been developed to create, from quantum-chemically tailored high-hyperpolarizability molecular building blocks, nanostructurally acentric self-assembled superlattices (SASs). The electro-optic response, linear optic properties, and refractive indices of these structurally regular and robust films can be additionally tuned by intercalating thin (1–5 nm) organic or metal oxide sheets or other structures. The electro-optic figures-of-merit of the SAS structures far exceeds that of conventional inorganic electro-optic materials, and the first self-assembled phase modulators have recently been fabricated. Their performance confirms these expectations.

Another program concerns the self-assembly and properties of inorganic-organic and organic-organic heterojunctions to act as light-emitting diodes (LEDs) and photodetectors. Nanoscopic tailoring of transparent conducting oxide electrode-charge transporting layer interfaces with very thin, structurally well-defined, conformal, pinhole-free dielectric or charge transporting layers effects very large enhancements in device hole injection efficiency, photonic quantum efficiency, electrode-organic cohesion, and device robustness. The same approach allows tailoring of the transparent conducting oxide surface chemistry and deliberate introduction of disorder within charge transporting/light-emitting layers. Using various soft lithographic techniques, it is also possible to create emissive regions from sub-_m to nm length scales, both to effect pixelation for a variety of conventional to micro-display applications as well as to fabricate dense arrays of nanodiodes for ultra-high resolution sensing and emission. This effort also probes the question of how organic diode structures respond to dimensional contractions vis-ˆ-vis their well-understood inorganic analogues.

Related Publications
Davey, M.H.; Lee, V.Y.; Miller, R.D; Marks, T.J. "Synthesis of Aryl Nitroso Derivatives by tert-Butyl Hypochlorite Oxidation in Homogeneous Media. Intermediates for the Preparation of High-Hyperpolarizability Chromophore Skeletons," J. Org. Chem., 1999, 64, 4976.

Li, W.; Wang, Q.; Shaheen S.E.; Chou, H.; Jabbour, G.E.; Anderson, J.; Lele, P.; Cui, J.; Kippelen, B.; Peyghambarian, N.; Armstrong, N.R.; Marks, T.J. "Spin-Coating Processes for Covalently Interlocked Light-Emitting Device Structures, Advanced Materials," 1999, 11, 730-734.

Koo, K.; Marks, T.J. "Silicon Modified Ziegler-Natta Polymerization. Catalytic Approaches to Silyl-Capped and Silyl-Linked Polyolefins Using "Single-Site" Cationic Zielger-Natta Catalysts," J. Amer. Chem. Soc., 1999, 121, 8791.

Beswick, C.L.; Marks, T.J. "Significant Zr-Alkyl Group Effects on Ion Pair Formation Thermodynamics and Structural Reorganization Dynamics in Zirconcenium Alkyls," Organometallics, 1999, 18, 2410-2412.

Tian, S.; Arredondo, V.M.; Stern, C.L.; Marks, T.J. "Constrained Geometry Organolanthanide Catalysts. Synthesis, Structural Characterization, and Enhanced Aminoalkene Hydroamination/Cyclization Activity," Organometallics, 1999, 18, 2568.