This invention discloses a new class of dopants that allows easy tuning of the chem., phys., optical and/or electronic properties of the doping agent in order to carefully adapt it to the desired application, such as org. solar cells or solid state dye-sensitized solar cells. The invention relates to electrochem. devices comprising complexes of cobalt comprising at least one ligand with a 5- or six membered, N-contg. heteroring. In the context of the invention, the complex (or a salt comprising the complex) of the invention is used to adjust, in particular increase the cond. of an org. charg...