(548a) Photoexcitation Dynamics in Nanomaterials

Non-adiabatic molecular dynamics (NAMD) implemented within the time-dependent density functional formalism (TDDFT) is applied to study ultrafast photoinduced dynamics in novel nanoscale materials, including dye and polymer sensitized semiconductors, quantum dots and carbon nanotubes. The classical-path, mean-field and surface-hopping approaches to NAMD are formulated within TDDFT for electron-nuclear dynamics. Particular attention will be given to

a) The interfacial electron injection from molecular and polymeric chromophores into the TiO2 surface, which drives the Gratzel solar cell and illustrates the molecule-semiconductor contact problem in molecular electronics and photoelectrochemistry.

b) The electron-vibrational and Auger relaxations of photoexcited states in quantum dots (QD), which determine the efficiencies of hot carrier accumulation and carrier multiplication in QD solar cells.

c) The electron-phonon scattering in carbon nanotubes, which affects conductivity and characterizes nanotube potential for use in nanoscale electronic devices.