Novel photo-cross-linkable hole-transporting polymers:: Synthesis, characterization, and application in organic light emitting diodes

Novel polymeric hole-transporters P1 through P4 were synthesized based on triarylamine units in the backbone with pendant oxetane groups which can be used for photo-cross-linking. These polymers were characterized by NMR spectroscopy, GPC, IR spectroscopy, and DSC. Their electrochemical properties were investigated by means of cyclic voltammetry. Multilayer organic light emitting devices were fabricated layer by layer using inexpensive solution based methods like spin-coating followed by a cross-linking step. UV spectroscopy was used to prove that the spin-coated layers are totally insoluble after the cross-linking process. The hole-transport capabilities of the polymers were evaluated in hole-only devices and finally multilayer OLEDs were fabricated to test the performance of the synthesized compounds.