Dyes on TiO2: ReaxFF + TDDFT study
Reactive Molecular Dynamics simulations with ReaxFF have been used successfully in combination with Time-Dependent Density Functional Theory (TDDFT) calculations to disclose structural features, aggregation characteristics, dynamics and spectroscopic properties of an organic dye adsorbed on a titania substrate. These represent the main constituents of dye sensitized solar cells (DSSC) and the realistic description obtained through the multi-level theoretical approach has revealed, in line with the experimental results, ordered dye domains, packed molecules and strong anchoring mechanisms of the dyes to the substrates. Aggregation of the dyes red-shifts the absorption spectrum.