Patent ID: 7923128

Claim:
An organic electroluminescent device comprising: a light-emitting layer containing a light-emitting material and a host material; a hole injection-promoting layer; and a hole-transporting layer containing a hole-transporting material; provided in this order between a pair of electrodes; wherein the hole injection-promoting layer contains a hole-transporting material and has a thickness of 0.1 nm to 3 nm; and the relationship Ip1<Ip2<Ip3 is satisfied, when Ip1 is defined as the ionization potential of the hole-transporting material of the hole-transporting layer, Ip2 is defined as the ionization potential of the hole-transporting material of the hole injection-promoting layer, and Ip3 is defined as the ionization potential of the host material; wherein the light-emitting material is a phosphorescence emitting material, and wherein the hole injection-promoting layer is in the form of islands.