context: Overall, crosslinking the sensitizers under copper-free conditions lead to an increase of the photovoltaic performances of all the DSSCs with both electrolytes. For NiO photocathodes, the Jsc is decreased owing to most probable iodide association with triazole, but it is compensated with the increase of Voc and ff. Crosslinking of the dyes with copper(I) catalysis is also possible, but the resulting solar cells exhibit lower performances, showing that copper has poisoned the devices.
answer: NiO 