The theoretical and computational studies of dye sensitized solar cells (DSSCs) can contribute to a deeper understanding of these
types of solar cells. The DSSCs are the novel design of solar cells which could be used as power producing windows or skylights.
They represent a particular promising approach to a direct conversion of sunlight into electrical energy at low cost and with high
efficiency. The light adsorption occurs in dye molecules adsorbed on a highly porous structure of TiO2 film. Despite the progress
in the efficiency and stability of these solar cells, there is still a room of research on some of their operational aspects that are still
not understood. One process, for which there is limited information, is the time taken to upload the dye on the TiO2 nanoporous
film. The processes followed experimentally for dye uptake is by dipping the TiO2 semiconductor electrode into the dye solution
for periods of several hours to several days. However, such long dipping times are not economical for industrial production of
DSSCs. The factors controlling this process are not yet fully investigated. We propose a simple model based on the Langmuir
isotherms to study and understand the diffusion and adsorption of the dye molecules in TiO2 films. Our computational modelling
results show that the adsorption of dye into the TiO2 nanotubes film is controlled by the diffusion coefficient, the adsorptiondesorption
ratio and the initial dye concentration. Our results show that the initial dye concentration plays an important role on the
surface coverage. It is also noted that for a higher concentration shorter immersion time is needed for the sufficient surface coverage.
Furthermore, it is observed that for the large values of the adsorption-desorption ratio there is a delay in the diffusion of dye
molecules on the surface.