P1 push-pull dye as a case study in QM/MM theoretical characterization for dye-sensitized solar cell organic chromophores**

In this work, an accurate modelling of the absorption spectrum and of the ground and excited state redox properties of the P1 dye – a benchmark system in p-type Dye-sensitized Solar Cells (p-DSCs) – is presented. The computed values were obtained by means of a QM/MM approach that combines a low computational cost with a proper treatment of the effects of the environment. The good agreement between our theoretical-computational estimates and the available experimental data underlines how a proper description of the redox thermodynamics of the ground and electronic excited states of the dye in a realistic environment can be provided by in silico modelling.