ELECTRONIC COUPLING CALCULATIONS FOR ULTRAFAST PHOTOINDUCED CHARGE TRANSFER PROCESSES FROM AROMATIC ADSORBATES TO TiO_2 NANOCRVSTALS

摘要

Structural and electronic properties of dye-sensitized semiconductornanostructured materials have been studied by means of quantum chemical calculations. Density functional calculations of a number of TiOi clusters, 1 - 2 nm in diameter, show the emergence of quasi-bulk properties in small nanocrystals. Geometry optimizations of aromatic sensitizers and ruthenium dyes on TiO2 clusters and surfaces provide atomistic models of dye-sensitized semiconductor interfaces. Information about the electronic properties of dye-semiconductor interfaces is obtained from electronic structure calculations. This includes information about the role played by anchor and spacer groups as ediators of electron transfer, photoinduced charge transfer mechanisms from explicit calculations of excited states, and electron transfer rates from calculated electronic coupling strengths.