Electrical and luminescence characterization was performed on 16 dye sensitized solar cells with different formulations, from different industrial and academic sources. Most of the cells were fabricated in pre-industrial pilot lines. The cells were put through a light soaking period up to 150 hours and then re-characterized. The results show the commonly observed increase in J sc with light soaking is due to a decrease in the conduction band energy (with respect to the electrolyte) and an increase in the injection rate and efficiency. The strong correlation between the luminescence decay lifetime (<200 ps to 5 ns) and the photocurrent (7 to 13 mA cm À2 ) shows that the luminescence decay is a useful monitor of injection rates in these cells. The very slow injection shown by some cells implies substantial losses at the injection step. The data point to a need to understand and improve the TiO 2 processing and dyeing conditions in the industrial setting as well as the need to focus injection studies on the full range of dynamics present in the cells.