In a first embodiment of the present invention, in order to increase the
number of holes injected into the emissive layer, an intermixed layer is
formed from the intermixing of the hole transport layer ("HTL") and the
emissive layer. The intermixed layer is between the HTL and the emissive
layer of the OLED device. Alternatively, in a second embodiment of the
present invention, in order to increase the number of holes injected into
the emissive layer, a separate interlayer is incorporated within the OLED
device. The interlayer is comprised of a hole transport material in which
one of its components is at least partially replaced with one of the
components of the emissive layer that is responsible for hole injection
and transport. The separate interlayer is between the anode and the
emissive layer of the OLED device. One or more intermediate layers may be
present between the interlayer and the anode such as, for example, a HTL
may be present between those two layers.