Quantum Dynamics of Light-Induced Charge Injection in a Model Dye–Nanoparticle Complex

Abstract

We present a detailed description of the direct charge injection mechanism in a coupled dye–TiO2 nanoparticle (NP) using a full quantum dynamical simulation framework. The method employed here is based on a time-dependent tight-binding model to describe the system under nonequilibrium conditions. By using this tool, we performed a simulation showing a full time-dependent picture of the photoabsorption process in type-II dye-sensitized solar cells (direct charge injection mechanism from the dye to the TiO2 NP). This task is accomplished by tuning the frequency of an applied sinusoidal time-dependent electric field with the frequency of the dye–TiO2 NP’s main absorption peak. We find that during the field irradiation there is a net charge transfer from the dye to the NP superposed with a typical charge oscillation due to absorption of radiant energy.