The conductive glass substrates constitute one of the most costly components of a dye solar cell. Hence, investigation of alternative materials is highly motivated. In this contribution we focus on using stainless steel which has been shown to be stable in electrolyte soaking tests.

The suitability of stainless steel both as a photoelectrode and counter electrode substrate was examined in respect to performance and stability. Complete solar cells were built and analysed using photovoltaic characterization methods, electrochemical impedance spectroscopy (EIS), and open circuit voltage decay. Recombination from the substrate to the electrolyte was investigated with substrate - counter electrode cells.

The results show 4.7 % and 3.5 % efficiencies for dye solar cells with stainless steel as a photoelectrode and counter electrode substrate, respectively. A significant part of this work was to make quantitative analysis of a single electrode performance. Here the voltage over a single electrode was determined in two electrode mode based on EIS measurements made as function of cell current. The conventional data analysis based on external cell voltage was found to be inadequate and even misleading. As a result of these detailed studies, we were able to find that the stainless steel photoelectrode substrate had affected negatively the electrochemical response of the dye TiO₂ layer whereas in the case of counter electrode substrate it remained unaffected. This observation is important for practical design of a reliable flexible dye solar cell.