We present a novel n-type doping technique for organic semiconductors using the metal complex bis(terpyridine)ruthenium as a strong donor. Owing to its low oxidation potential, the reduced neutral form of the donor complex allows an electron transfer to the matrix. This enables n-type conduction that has been seldom reported in metallophthalocyanine systems doped with organic compounds. The n-type zinc-phthalocyanine layers are characterized by the conductivity and the field-effect measurements. By sequential coevaporation of p- and n-doped layers, we have prepared the first stable and reproducible organic
homojunction of zinc-phthalocyanine. The diode exhibits surprisingly high built-in voltage attractive e.g. for organic solar cell applications. The temperature dependence of the
current-voltage characteristics does not follow the standard Shockley theory of pn-junctions. We explain the behavior of the ideality factor and the saturation current by deviations from the classical Einstein relation at low temperatures.
To realize organic solar cells with high performance, we developed a novel way of stable n-doping using cationic dyes in electron transport materials. In our approach, the volatile donors are created in-situ from stable precursor compounds. Using the cationic dye pyronin B (PyB) as a model precursor, we carried out conductivity and field effect measurements to characterize the properties of doped naphtalene tetracarboxylic dianhydride (NTCDA) thin film. The results show a strong increase in n-type conductivity. Combined FTIR, UV/VIS/NIR and mass spectroscopic measurements suggest the formation of leuco pyronin B during sublimation of pyronin B chloride, and a subsequent charge transfer between dopant and matrix providing free electrons, which increase the n-type conductivity.