US Patent 8933622 Organic electroluminescence element

Disclosed is an organic electroluminescent device having a longer drive life. Specifically disclosed is an organic electroluminescent device (100) comprising an organic material layer (16), which is composed of a hole transporting layer (164), a light-emitting layer (166) and an electron transporting layer (167), between a pair of electrodes, namely a cathode (18) and an anode (12). The light-emitting layer (166) (having a film thickness (dM) of 5-3000 nm) contains a luminescent dye and a host material. The first oxidation potential (ED+) of the luminescent dye is lower than the first oxidation potential (EH+) of the host material, while the first reduction potential (ED−) of the luminescent dye is lower than the first reduction potential (EH−) of the host material. The film thickness (dE: 5-3000 nm) of the electron transporting layer (167) and the film thickness (dH: 5-3000 nm) of the hole transporting layer (164) satisfy the following relation: dH≦dE.