DURIP: Four-Dimensional Electronic Raman Spectroscopy for Elucidating Coupled Energy Transfer Processes in Nanomaterials

We describe instrumentation that will augment our current research capabilities and enable new experiments in order to understand and exploit coupled energy transfer (CET) processes in complex molecular networks, and which will serve to support a current AFOSR grant: PECASE: Multi-dimensional Vibrational-Electronic Spectroscopy to Probe Electronic-to-Vibrational Energy Transfer in Hybrid Materials awarded through AFOSR. Specifically, we aim to develop a multi-mode and multi-dimensional coherent spectrometer capable of directly observing the dynamics that accompany CET processes with unprecedented temporal and spectral resolution, and across an energy range that spans the mid-infrared to ultraviolet regions. This instrument will support two main goals of our current AFOSR effort: Goal 1: to measure and predictively model the rates of CET processes in solution-phase and thin-film assemblies of QDs and organic ligands. Goal 2: to use our mechanistic understanding of CET processes to design assembly architectures and chemistries to achieve previously unrealized coupled ET schemes. DURIP funding is requested to build this one-of-a-kind instrument, which includes I) development of powerful light sources, II) novel detection modalities that will dramatically increase sensitivity and resolution over current methods, and III) high-order nonlinear spectrometer. The proposed instrument will have major implications beyond the particular problem described here, in serving other AFOSR priorities as they relate to understanding complex and highly correlated materials. The proposed instrument will also serve as an important research and educational tool for students in collaboration with the Searle Center for Teaching Excellence at Northwestern University. The proposed work will encourage students to develop creative thinking skill by connecting physical measurements of complex systems to critical challenges at the frontiers of molecular physics.