Abstract
The ionization-assisted method was used to prepare vinyl polymer films of tetraphenyl-diaminobiphenyl (TPD). The electron irradiation in the deposition process was effective to enhance the polymerization reaction. The reaction appears to be driven by neutral radicals produced by the electron irradiation. The polymerization was also enhanced by increasing the substrate temperature during the deposition, and by post-annealing in vaccum. At an appropriate condition, the average molecular weight of 2.2×10^4 was obtained at the yield of 91%. The polymerized film of TPD-ac was applicable as the hole transport layer of organic EL devices. The device performance was improved in accordance with the enhancement of polymerization.
