Dr. Bragg’s research focuses on the characterization of light-driven chemical dynamics and material behaviors. A common thread throughout his research is the use of ultrafast spectroscopic techniques to observe processes that occur on timescales shorter than 10-13 s (timescales of atomic and molecular motions). These techniques are used to determine fundamental structure-dynamics relationships that underlie molecular and material responses to excitation with light.
Specific research topics of interest include:
1) Properties and dynamics of excited conjugated materials. Conjugated materials have received considerable attention for use in flexible optoelectronics (e.g. LEDs and solar cells). The goal of our work is to determine what structural attributes at the molecular level (e.g. conformations and intermolecular interactions) define or control the properties and dynamics of photoexcitations within these materials.
2) Light-driven or switchable bond formation and isomerization. These processes offer means for converting light energy to mechanical or chemical energy or to reversibly alter the photophysical properties of materials. In our work we directly interrogate the relaxation mechanisms associated with these processes in order to determine structure-dynamics relationships that could form principles for design or optimization of photoswitchable materials.
3) Photodynamics of plasmonic metal nanoparticles and assemblies. Plasmonic materials have promise for concentrating electric fields of light and for pan-chromatic absorption of light energy. The goal of our work is to determine how the architecture of these nanomaterials determines their photoresponses and potential for light collection or harvesting for optical and chemical processes.
