Photoelectrochemical Effects and (Photo)Conductivity of “N-Type” Phthalocyanines

In vacuo thin films of the phthalocyanine derivatives TPyTAPZn and F16PcZn show n-type behavior in thermopower and conductivity measurements. After exposure to air the properties are changed characteristically. Photoelectrochemical experiments show that while TPyTAPZn still behaves like an n-type semiconductor, F16PcZn exhibits the properties of a photoconductor. Time-dependent measurements give further insight into the differences between the two materials in their interaction with gaseous dopants. The results are discussed in terms of different positions of the HOMO- and LUMO-orbitals of TPyTAPZn and F16PcZn taken from UPS-measurements.