Patent ID: 8049407

Claim:
An organic electroluminescent element comprising: a pair of electrodes, and a plurality of organic compound layers being disposed between the pair of electrodes and which include a luminescent layer containing a blue phosphorescent luminescent material and only one kind of host material having the lowest excited triplet energy (T 1 ) of 272 kJ/mol (65 kcal/mol) or more, hole transport layers, and electron transport layers, wherein one of the hole transport layers is a layer adjacent to the luminescent layer, and when the ionization potentials of the luminescent layer, the hole transport layer adjacent to the luminescent layer, and another of the hole transport layers, respectively, are designated to Ip 1 , Ip 2 and Ip 3 , the relationship Ip 1 >Ip 2 >Ip 3 is satisfied, wherein Ip 2 is in the range of 6.0 to 5.5 eV, wherein one of the electron transport layers is a layer adjacent to the luminescent layer, and when the electron affinities of the luminescent layer, the electron transport layer adjacent to the luminescent layer, and another of the electron transport layers, respectively, are designated to Ea 1 , Ea 2 and Ea 3 , the relationship Ea 1 <Ea 2 <Ea 3 is satisfied, and the lowest excited triplet energy T 1 ) of the electron transport layer adjacent to the luminescent layer is 272kJ/mol (65kcal/mol) or more, and wherein the Ea 1 is 2.1 eV or more, the Ea 2 is in the range of 2.2 to 3.1 eV, and the Ea 3 is 2.6 eV or more.