MSE Seminar: Dr Aaron Lindenberg, Stanford University

Description

What happens after photon absorption in next generation photovoltaic materials?

Novel characterization techniques developed over the past two decades have revolutionized our ability to visualize the microscopic, atomic-scale processes that determine the functional properties of materials. The overarching challenge here is that the relevant time-scales and length-scales for these processes are typically 10^-13 seconds (100 femtoseconds) and 10^-10 m (1 Angstrom) such that our view of how a material or device functions is often blurred out in time or in space. Real-time x-ray and electron scattering techniques, which are directly sensitive to the dynamical response of atoms, provide powerful means for probing these processes which often underlie optoelectronic functionality. In this talk I will present recent progress applying such techniques to the hybrid perovskites, probing the local structural rearrangements and charge separation dynamics that occur following above gap photo-excitation on Angstrom and nanometer length-scales. These measurements provide new insight into the role of ultrafast atomic-scale distortions in enabling the unique optoelectronic properties of these materials.

Dr. Lindenberg's research is focused on visualizing the ultrafast dynamics and atomic-scale structure of materials on femtosecond and picosecond time-scales. X-ray and electron scattering and spectroscopic techniques are combined with ultrafast optical techniques to provide a new way of taking snapshots of materials in motion. Current research is focused on the dynamics of phase transitions, ultrafast properties of nanoscale materials, and charge transport, with a focus on materials for information storage technologies, energy-related materials, and nanoscale optoelectronic devices.