Electronic structure, optical properties, and electron dynamics in organic dye-sensitized TiO2 interfaces by local hybrid density functionals

In this work, we present theoretical investigations of dye-sensitized solar cells (DSSCs) using linear response time-dependent density functional theory (LR-TDDFT) and electron dynamics within the hybrid TDDFT/configuration interaction methodology. To evaluate the potential of local hybrid density functionals for such hybrid systems, we study the electronic properties of two organic dyes, both isolated and anchored on a typical semiconductor substrate (TiO2). The implemented strategies can accurately predict electronic structures, optical properties, and energetic alignments of the investigated dye@TiO2 systems. The accuracy of charge transfer excited states and the hybridization between the interfacial states depend appreciably on the used exchange correlation functional. This work emphasizes the performance of local hybrid functionals in comparison to the most commonly used global hybrid and range-separated hybrid functionals. Investigation of laser-induced charge migration dynamics sheds light on the effect of hybridization between the dye and the substrate at the interface on both the population transfer dynamics and the charge injection rate.