Research

Research in the Harel lab is aimed at developing novel tools to study how interactions at the molecule scale influence macroscopic observables in complex and dynamical systems from semiconductor nanocrystals to living organisms. These local changes may be, for example, disruptions in the intramolecular forces that hold a protein in its folded state, weak lattice phonons that scatter charge carriers in semiconductors, or light-induced electron transfer in photosynthetic organisms. A fundamental understanding of the connection between such microscopic interactions and their influence on macroscopic system properties in complex, condensed- or solid-phase environments is critical to informing the designs of novel materials with tailored functionality. Our approach is to develop tools that allow complex processes to be tracked across vast regions of space, time, and energy, and to uncover general rules, based on these measurements, that control function. This novel strategy combines ideas from two enormously successful fields – nuclear magnetic resonance (NMR), which has transformed analytical chemistry, structural biology, and forms the basis for advanced medical imaging, and ultrafast spectroscopy, which has revolutionized our understanding of chemical transformations on time scales of atomic motion. To advance these goals, we have been moving along two different, but complimentary paths: (1) developing and implementing sophisticated multi-dimensional coherent optical spectroscopic methods on quantum confined nanostructures and strongly coupled multi-chromophore systems, and (2) developing imaging methods to directly track long-range energy transfer at the single-particle level. Combining the ensemble and single-molecule approaches is critical to successfully tackle these problems at the appropriate temporal, spectral, and spatial scales.