Abstract
This thesis presents an integration of molecular dynamics simulation with computational mass transfer to predict the voltage-current performance of dye-sensitized solar cells (DSSCs). Ionic liquid electrolytes are the major transport medium that transfers redox charges (typically iodide/ triiodide) between the anode and the cathode. The flux of the species in the electrolyte is mainly diffusion transport and may constrain the solar cell performance. Molecular dynamics simulation technique was employed to assess the diffusion coefficient and ionic conductivity of the charge transport. The ionic conductivity was compared with an experimental result carried out by a rotational electrode test. The diffusion coefficient was then input to a computational mass transfer code and the depletion of redox charges at the electrode can be calculated. Electrochemical performance of the solar cell is predicted and shows in good agreement with the experimental result. In order to maximize the DSSC performance, optimization of the design parameters has to be done. The optimal ionic liquid concentration was found to be 0.5M for [I-] and 0.055M for [I3-] at 303K. The expected energy conversion efficiency of such kind of photoelectrochemical cells is able to reach 20%, if proper parameters are tuned further, such as the porosity of the porous TiO2 is set to 0.45, the quantum efficiency reaches unity and etc.