Veröffentlichungen und Präsentationen

In this study, we attempted to develop a simulation to better understand the kinetic of the dye regeneration process in photoanodes of dye-sensitized solar cells (DSSCs). For that purpose, a numerical model was developed using finite element simulation in COMSOL Multiphysics®. The transport of diluted species by diffusion was considered the essential process to define the system. The kinetics of the dye regeneration reaction at a DSSC can be probed by scanning electrochemical microscopy (SCEM). Such analysis is based on recording an approach curve of a microelectrode probe towards the illuminated photoanode. The photoanode of DSSCs could be ZnO or TiO2. The model must consider the influences of the reaction kinetics (the quantity of interest), experimentally adjustable parameters like light intensity and working distance and the properties of the material (porosity, tortuosity of the photoanode). We quantitatively describe the mass transport of the mediator and electron transfer kinetics occurring in the photoanodes of DSSC. The numerical simulation stepwise refines the treatment of light absorption, electron injection from the dye to the conduction band, dye regeneration and loss processes. The simulation results obtained were compared to the experiment. Overall, this model should provide a comprehensive framework for extracting physicochemical parameters from SECM approach curves and predict the impact of improved preparations for the overall performance of DSSCs.