Harnessing Solar Power: Novel Strategies for Rational Design of Photocatalysts and Photovoltaic Materials

The goal of this effort was to develop the spectroscopic infrastructure to be able to probe non-Born-Oppenheimer couplings near conical intersections in the condensed phase. This effort required 2D electronic spectroscopy to be extended to broader bandwidth, higher sensitivity and improved resolution of coherent dynamics to detect phase. We invented a new approach to 2D spectroscopy to address these issues: Gradient-Assisted Photon Echo Spectroscopy (GRAPES).This approach allowed improved bandwidth due to purely reflective optics, improved sensitivity due to elimination of laser power fluctuations in the indirect domain, and improved phase resolution. We applied this spectroscopy to a range of synthetic and natural photosynthetic light harvesting systems to examine the system-bath coupling (electronic-vibrational couplings) using coherences as a detailed probe of the environment.