Janice Reutt-Robey

Surface Chemistry & Nanoscale Energy Science

Our research focuses on molecular organization at surfaces, thin films and chemical interfaces. We begin with the properties of individual molecules to construct more complex spatial arrangements. We then explore how this chemical morphology leads to novel electronic and material properties with implications for energy science. Developing the tools and strategies to control chemical morphology and forge structure-property relationships is the core of our research.
Our main strategy for creating interfaces involves physical vapor deposition of atoms and molecules onto atomically-clean crystalline substrates. Additional methods, such as reactive co-deposition and liquid spray, are being developed to incorporate nonvolatile species (nanotubes/crystallites) into hybrid inorganic-organic films. The structure-property relations of these molecularly engineered interfaces are then explored with scanning probe microscopies and surface sensitive spectroscopies.

Current Projects
Nanopatterned Molecular Assemblies

Organic molecules spontaneously organize into molecular assemblies on solid surfaces in response to the balance of molecule-molecule and molecule-surface forces. These supramolecular structures further adopt mesoscale patterns in response to the interfacial stress between supramolecular film and growth substrate. Systematic investigations of pattern formation are leading to predictive models for molecular organization at interfaces. See "Isonicotinic Acid Molecular Films on Ag(111): I. XPS and STM Studies of Orientational Domains," H. Li, B. Xu, D, Evans, and J. E. Reutt-Robey, J. Phys. Chem. C 111, 2102-2106 (2007) for an illustration of our approach.

Ultrathin Molecular Semiconductors
Molecular semiconductors, such as pentacene and titanyl phthalocyanine, are molecular building blocks for electronic devices. Electron transport properties are strongly affected by molecular film architecture. This architecture mediates the alignment of electronic states near the Fermi level, as described in "Local Transport gap in C60 Nanochains on a Pentacene Template," D. Dougherty, W. Jin, W. Cullen, W. Dutton, J. E. Reutt-Robey and S. Robey, Phys. Rev. B 77, 073414/1-073414/4 (2008). We are researching the extent that thin-film molecular semiconductors can be electronically tailored by chemical morphology and molecular dopants.

Organic and Hybrid Materials for Photovoltaic Applications

Photovoltaic devices based upon organic donor-acceptor or inorganic-organic hybrid materials systems are inexpensive alternatives to the traditional silicon-based solar cell. The design challenge for these newer materials is to improve device efficiencies by separating donor and acceptor species on the lengthscale achieved in "Coverage Dependent Supramolecular Structures: C₆₀:ACA Monolayers on Ag(111)," B. Xu, C. Tao, E. Williams, and J. E. Reutt-Robey, J. Am. Chem. Soc. 128, 8493-8499. (2006). We are tracking nanophase separation and nanoscale variations in the electronic band alignment for fullerene - metal phthalocyanine systems and other promising molecular candidates for next-generation photovoltaic cells.