Preparation of organic semiconductive thin film by plasma polymerization of 3,4,9,10-perylenetetracarboxylic dianhydride and related compounds

Homogeneous semiconductive organic thin films were obtained by the radio-frequency (rf) plasma polymerization of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and related compounds such as 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) and perylene. The highest dc electrical conductivity of 1.0×10−1 S/cm at room temperature was obtained in the PTCDA-polymerized sample film prepared with a rf power of 10 W. The conductivity of the films prepared with a rf power of 60 W was lower by three orders of magnitude than those with a rf power of 10 W. Furthermore, the conductivities of the PTCDA- and the PTCDI-polymerized films decreased by exposure to air. In order to clarify these phenomena, the structure and optical properties of the sample films were examined based on the infrared, the electron spectroscopy for chemical analysis, and the ultraviolet-visible measurements.