Light-Induced Charge Carrier Dynamics at Nanostructured Interfaces Investigated by Ultrafast Electron Diffractive Photovoltammetry

Abstract

We present an ultrafast photovoltammetry framework to investigate thesurface charge carrier dynamics at the nanometer scale. Thisdiffraction-based method utilizes the feature-gated nanomaterialdiffraction pattern to identify the scattering sites and to deduce theassociated charge dynamics from the nanocrystallographicrefraction-shift observed in the ultrafast electron diffractionpatterns. From applying this methodology on SiO2/Si interface, andsurfaces decorated with nanoparticles and water-ice adsorbed layer, weare able to elucidate the localized charge injection, dielectricrelaxation, and carrier diffusion, with direct resolution in the chargestate and possibly correlated structural dynamics at these interfaces,which are central to nanoelectronics, photovoltaics, and photocatalysisdevelopment. These new results highlight the high sensitivity of theinterfacial charge transfer to the nanoscale modification, environment,and surface plasmonics enhancement and demonstrate the diffraction-basedultrafast surface voltage probe as a unique and powerful method toresolve the nanometer scale charge carrier dynamics.