Understanding the excited state charge dynamics, spin states, and structures is crucial for efficiently designing sustainable energy conversion materials, from molecules to bulk nanoparticles. This understanding allows us to predict the spatial and temporal properties of generated charges. However, observing early-time localized charge dynamics is challenging because optical energy primarily accesses delocalized frontier molecular orbitals. To overcome these limitations, we utilize time-resolved X-ray spectroscopies, which offer element and chemical specificity through nuclear level transitions.

We have developed pump-probe X-ray absorption and emission spectroscopic experimental methods to investigate the full electronic dynamics after the target material is excited by photons from delayed pulses. Time-resolved X-ray spectroscopies provide comprehensive insights into the charge transfer dynamics of sustainable materials, synthesized by other teams within our group, to reveal catalytic mechanisms. This cooperative feedback cycle among the teams enables the development of efficient strategies for creating sustainable energy materials.

Our X-ray spectroscopy team maintains relationships with research teams abroad and collaborates to study atomic-specific femtosecond-scale dynamics.