Influence of oligothiophene layer on PVK-based blue light-emitting diode

The α-sexithiophene, α-6T, was used as the hole injecting layer in polymer-based electroluminescent (EL) device. The hole basis of injection mechanism at the ITO/dye-doped poly(N-vinylcarbazole) (PVK) layer was investigated on the Fowler–Nordheim tunneling theory. The tunneling mechanism of holes is not applicable for the EL device that is fabricated in ITO/α-6T/dye-doped PVK/Al. We propose that the carrier injection barrier migrates from electrode (ITO)/organic layer (dye-doped PVK) to organic layer(α-6T)/organic layer (dye-doped PVK).