| 主权项 |
1. An organic electroluminescent device comprising a plurality of organic compound layers between a pair of electrodes, wherein
the plurality of organic compound layers include a luminescent layer, two or more hole-transporting layers, and two or more electron-transporting layers, the hole-transporting layers include a layer adjacent to the luminescent layer, the electron-transporting layers include a layer adjacent to the luminescent layer, the luminescent layer contains a host material and a luminescent material, the luminescent material is a metal complex containing a tri- or higher-dentate ligand, and when the ionization potential of the luminescent layer is designated as Ip0, the ionization potential of the hole-transporting layer adjacent to the luminescent layer among the hole-transporting layers is designated as Ip1, and the ionization potential of an n-th hole-transporting layer from the luminescent layer among the hole-transporting layers is designated as Ipn, these values satisfy the relationship represented by the following formula (1):
Ip0> . . . >Ipn-1>Ipn Formula (1) wherein n is an integer of 2 or more; and when the electron affinity of the luminescent layer is designated as Ea0, the electron affinity of the electron-transporting layer adjacent to the luminescent layer among the electron-transporting layers is designated as Ea1, and the electron affinity of an m-th electron-transporting layer from the luminescent layer among the electron-transporting layers is designated as Eam, these values satisfy the relationship represented by the following formula (2):
Ea0<Ea1<Ea2< . . . <Eam-1<Eam Formula (2) wherein m is an integer of 2 or more. |
