Flexible Dye-Sensitized Nanocrystalline TiO2 Solar Cells

The Dye-sensitized nanocrystaline TiO2 solar cell (nc-DSC) developed by Grätzel [1] has the potential to reach low costs in future outdoor power applications. In addition, due to its expected ease of production and possibilities to adjust its appearance, the potential for application is very broad. When plastic foil is used as a substrate for the nc-DSC the production and application possibilities are even bigger. Polymer foils are easier to handle in processing steps such as cutting of larger entities into smaller individual modules. Moreover the processing of foil into complete flexible solar cells could be realized by means of a continuous roll to roll proces. This implies that for the flexible nc-DSC a higher throughput in production could be realized. Also special applications requiring a certain flexibility of the solar cell, such as smart cards, come into play. In this paper the differences in cell performance and -stability between glass based nc-DSC's and polymer foil based nc-DSC's are studied. The ITO coating on the polymer foil appears to be a critical factor with respect to the photoelectrode stability. TiO2 sintered at low temperatures (150 °C) does not influence the cell stability in a negative way.