Synthesis of Cyclic Oligomer Having a Low Ionization Potential.

Synthesis of cyclic oligomer having a low ionization potential (Ip) is described. Ip of this cyclic oligomer was determined as 5.05 eV, which is lowered than that of corresponding poly(3,6-ethynyl-9-tetradecylcarbazole) (5.24 eV). This result indicated that the cyclic oligomer would be new candidate for hole injection and/or transport material in organic light-emitting diodes.