Spatially and Temporally Resolved Material Characterization at Interfaces
The overarching goal of this research is to surpass the existing analytical capability for nanometer scale spatially resolved material characterization at interfaces under ambient conditions. This is being accomplished through a distinctive merger of advanced spectroscopic and ultrafast time-resolved imaging, scanning probe microscopy, and mass spectrometry. There are two synergistic subtasks in this proposal. In Subtask 1, research is focused on enabling and advancing the ability of ambient surface sampling/ionization mass spectrometry, in combination with other imaging modalities, to study and characterize with submicrometer spatial resolution (100- 1000 nm) molecular and elemental constituents of material interfaces under real world conditions. In Subtask 2, research is focused on utilizing optical spectroscopic methods with high spatial and temporal resolution to provide an understanding of the ultrafast energy flow and chemical reactions in nanostructures and selected functional nanostructure assemblies by imaging individual nanoparticles and nanostructures with chemical contrast, nanoscale spatial resolution, and femtosecond time resolution. Combinations of techniques that capitalize on both optical spectroscopy and mass spectrometry will provide deeper chemical understanding of interfaces than could either discipline alone. Mass spectrometry operates on the molecular level, while our optical techniques probe nanostructures and their assemblies. The new techniques and tools developed under the umbrella of this research proposal to study and characterize a surface, with submicrometer spatial resolution with the ability to specifically identify a wide range of elements, molecular compounds from small molecules to large macromolecules, and functional domains, over a variety of time scales, will be of great utility in the advancement of the DOE mission (including solar energy utilization, energy storage, fuel cells, and catalysis).