A range of semiconductor nano-materials is explored in respect to their ability to (i) absorb light and (ii) form charge transfer states. TDDFT computation is used for analysis of excited states of atomistic models. The spatial localization of electron and hole components of the excited states analyzed along with size of the exciton. The dynamics of formation of charge transfer states is explored by using on-the-flight non-adiabatic coupling along molecular dynamics trajectory. Electronic structure data parametrize equation of motion for the reduced density matrix. Case studies of functionalized TiO2 thin films and Si nanowires support the conclusion that controlled modification of the morphological features of semiconductor nanomaterials, such as doping, impurities, and surface defects facilitate formation of unbound excitons and charge transfer states. The latter ones provide an easy sweeping off the carriers to catalytic sites or contacts -- which is important for design of light harvesting mesoscopic metamaterials. This research is supported by USD HPC resources, NSF award EPS0903804, and by DOE, BES � Chemical Sciences, NERSC Contract No. DE-AC02-05CH11231, allocation Award 85213 'Computational Modeling of Photo-catalysis and Photoinduced Charge Transfer Dynamics on Surfaces'.

Charge transfer in surfaces with doping, impurities, and surface defects

245th National Meeting (2013)

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