First-principles modeling of dye-sensitized solar cells: From the optical properties of standalone dyes to the charge separation at dye/TiO2 interfaces

In this chapter we present an exhaustive overview of the recent theoretical models and computational strategies developed to afford a realistic description of the different device components integrating dye sensitized solar cells (DSSCs), and the complex physical-chemical phenomena taking place at their interfaces. Here we discuss first-principles modelling of transition metal complex (TMC) dye sensitizers and their interaction with the TiO2 semiconductor models, with the aim of showing how theory can effectively lead toward the successful exploitation of the rich photophysics of these materials in the DSSCs field. Overall, we show how these calculations, combined with the appropriate experimental measurements and data-driven analysis, can be opportunely used to set up useful design rules for the optimization of the properties of the different device components, as for instance, extension of into the VIS-nIR nIR (visible-near infrared) absorption window and lifetimes of the dye sensitizers, or optimization of the charge separation at the dye/semiconductor interface.