Patent ID: 7839078

Claim:
An organic electroluminescent element comprising a plurality of organic compound layers between a pair of electrodes and comprising at least a luminescent layer and a buffer layer adjacent to the luminescent layer, wherein: the luminescent layer comprises at least two host materials and at least one luminescent material, the buffer layer comprises at least one of the host materials and at least one dopant material having a charge trapping function, the at least two host materials in the luminescent layer comprise a hole transportable host material and an electron transportable host material, and the buffer layer comprises a hole transportable buffer layer that is formed at the anode side of the luminescent layer and an electron transportable buffer layer that is formed at the cathode side of the luminescent layer, wherein the hole transportable buffer layer comprises the at least one of the host materials and at least one dopant material having an electron trapping function as the charge trapping function, and the electron transportable buffer layer comprises the at least one of the host materials and at least one dopant material having a hole trapping function as the charge trapping function, wherein the at least one dopant material having a hole trapping function has a lower ionization potential than an ionization potential of the at least one of the host materials in the buffer layer, and wherein the at least one dopant material having an electron trapping function has a higher electron affinity than an electron affinity of the at least one of the host materials in the buffer layer.