ABSTRACT

The ultrafast electron transfer from chemically adsorbed dye molecule to nanocrystalline metal-oxide semiconductor particles in a so-called dye-sensitized solar cell is one of the key factors of the high conversion efficiency. These electron transfer processes are often observed by ultrafast pump-probe experiments. In this work, we use the general linear response theory to compute the ultrafast photochemical kinetics as well as the transient spectra of the dye-sensitized semiconductor nanoparticle. The initial state of the electron transfer process is considered as the photo-excited state of the dye molecule, and a simple tight-binding model is used to mimic the ET reaction final state, which is a charge-separate state where the dye is in its positively-ionized state. Numerous numerical examples are given to show the kinetics revealed by the transient absorption spectra both in the reactant state and in the product state, and the quantum beat phenomena in these spectra. The properties of the final state have significant influence on the observed rate and spectra. We organized more realistic quantum chemistry studies to obtain better information about both the initial and the final state of the ET reaction.