Interfacial electron transfer energetics studied by high spatial resolution tip-enhanced Raman spectroscopic imaging

• Applicant: Professor Dr. Alfred J. Meixner
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2008 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 84887002

Interfacial electron transfer (IET) plays an important role in many chemical and biological processes. Specifically, IET in dye sensitized TiO2-based solar energy conversion systems is critical to new energy technology and sciences. However, the microscopic mechanism of interfacial ET is not well understood with regard to molecule-surface structure and interaction, energy flow across the interface, and vibrational relaxation barrier of IET. This collaborative research effort involving the Lu group at Bowling Green State University (USA) and the Meixner group at Eberhard Karls University in Tubingen (Germany) will focus on microscopic mechanisms of IET for model systems of dye sensitized TiO2 nanocryostals and crystalline surfaces. Lu has established a strong program on IET dynamics and mechanism and Raman spectroscopy analysis of the IET energetics on dye-TiO2 nanoparticles; whereas Meixner has a cutting-edge near-field Raman spectroscopy technical program on singlemolecule Raman imaging on single crystal surfaces. This is a perfect match to study an important scientific problem of solar energy conversion with world-rate advanced technology. A combined approach of state-of-the art local probe microscopy techniques such as 10-nm high spatial resolution near-field optical Raman microscopy (Meixner), AFM/STM tip enhanced single-nanoparticle Raman spectroscopy (Lu) in combination with Heller theory (time dependent wave packet scattering theory for spectral analysis) (Lu) will be used to bridge the gap from conventional ensemble-averaged level understanding to molecular details with unprecedented spatial resolution.

• DFG Programme: Research Grants
• International Connection: USA
• Participating Person: Professor Dr. Peter Lu