Molecular Interfaces to Single-crystal Anatase Surfaces
EMSL Project ID
25676
Abstract
The anatase form of TiO2 is of great interest as a substrate for a variety of photochemical and photoelectrochemical pathways for solar-to-electrical and solar-to-fuel conversion. A number of organometallic complexes have been shown to yield facile electron injection into TiO2. The resulting charge separation can be used to generate an electrical current or to induce catalytic oxidation reactions, depending on the nature of the molecular complex. The integration of TiO2 with the unique chemical properties of molecular catalysts could lead to significant increases in efficiency of solar-to-electrical and solar-to-fuel conversion. However, the nature of the ligand-to-TiO2 charge transfer process remains poorly understood. The goal of the proposed research is to investigate the use of molecular monolayers as highly tunable interfaces between anatase TiO2 and organometallic complexes. In this proposed research, the Hamers group at Wisconsin will team with team with EMSL scientists to investigate the formation and electrochemical properties of molecular layers formed on single-crystal anatase samples Molecular layers will be formed using a novel photochemical functionalization strategy recently developed by the Hamers group and successfully applied to single-crystal rutile and nanocrystalline anatase. Experiments will be conducted on single-crystal anatase to achieve a fundamental understanding of the molecular interfaces and how the molecular interfaces affect electron-transfer properties through the layers. In the proposed research, we will use XPS and FTIR to characterize the chemistry of the molecule-anatase interface. Electrochemical measurements will be used to characterize the electron-transfer properties into solution-phase redox species and using surface-tethered redox species. As time permits, this research will be extended to more complex molecular materials such as Ru-based complexes used as dye sensitizers.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-25
End Date
2010-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Robert J. Hamers, Scott A. Chambers, Paul E. Evans, Ryan Franking, Zachary Gerbec, Padma Gopalan, Heesuk Kim, Elizabeth C. Landis, Bo Li, Michael W. McCoy, Takeo Ohsawa, and Rose Ruther,
"Molecular and Biomolecular Interfaces to Metal Oxide Semiconductors", Physica Status Solidi, submitted for publication 7/09
Ryan A. Franking, Elizabeth C. Landis, and Robert J. Hamers, ?Highly Stable Molecular Layers on Nanocrystalline Anatase through Photochemical Grafting?, Langmuir, Submitted 3/09.