Design Enhancements for High Performance Dye-Sensitized Solar Cells

Due to the abundance of solar energy, solar cells are considered as a renewable source of energy to replace conventional fossil fuels. Compared to the silicon-based photovoltaic (PV) cell, the next generation dye-sensitized solar cell (DSSC) offers the advantages of increased absorption of visible light, high efficiency potential, less energy intensive and lower-cost manufacturing process, colorable design, and lightweight material options. DSSC is a photo-electrochemical system that is based on a photosensitive dye-sensitized semiconductor (mostly titanium dioxide, TiO₂) anode and an iodide-based electrolyte. In order to improve the performance of current DSSC systems, we proposed various design improvement schemes through the use of TiO₂ nanotube (TONT) arrays and a multistack design of single cells. Through design modifications, approximately 38% improvement in the performance compared to conventional DSSC is reported. Moreover, optical enhancements to increase the amount of incident light on the cell were applied to DSSCs to further improve its performance by application of Fresnel lenses on top of the DSSC and the use of light reflecting material such as Aluminum on the rear side of the cell. The polarization curves for different designs were measured using a potentiostat and the performance of each cell was compared. Optical enhancements improved the power output by 27% compared to normal cells. A semi-empirical DSSC model was also developed based on the experimental results and the change in the performance of different designs was examined. Based on the model, the necessary conditions for maximum performance could be determined.