Organic electroluminescence device
View Patent ↗Disclosed is an organic electroluminescence device containing a pair of electrodes on a substrate, two or more luminescence layers disposed between the electrodes, and an intermediate layer containing a charge transporting material and disposed between the two or more luminescence layers, each of the two or more luminescence layers contains at least one phosphorescence material selected from a blue phosphorescence material having an emission peak from 420 nm to less than 500 nm, a green phosphorescence material having an emission peak from 500 nm to less than 570 nm, and a red phosphorescence material having an emission peak from 570 nm to 650 nm, the phosphorescence material contained in the respective luminescence layers having different emission peaks from one another; and the charge transporting material contained in the intermediate layer has an energy difference (T 1 ) of 2.7 eV or more between a ground state and an excited triplet state and the energy difference (T 1 ) of the charge transporting material is higher by at least 0.15 eV than T 1 of a phosphorescence material having the shortest wavelength emission among the phosphorescence materials contained in the two or more luminescence layers.
1. An organic electroluminescence device comprising a pair of electrodes on a substrate, two or more luminescence layers disposed between the electrodes, and an intermediate layer containing a charge transporting material and disposed between the two or more luminescence layers, wherein:
each of the two or more luminescence layers contains at least one phosphorescence material selected from a blue phosphorescence material having an emission peak from 420 nm to less than 500 nm, a green phosphorescence material having an emission peak from 500 nm to less than 570 nm, and a red phosphorescence material having an emission peak from 570 nm to 650 nm, the phosphorescence material contained in the respective luminescence layers having different emission peaks from one another;
the charge transporting material contained in the intermediate layer has an energy difference (T 1 ) of 2.7 eV or more between a ground state and an excited triplet state and the energy difference (T 1 ) of the charge transporting material is higher by at least 0.15 eV than T 1 of a phosphorescence material having the shortest wavelength emission among the phosphorescence materials contained in the two or more luminescence layers;
the two or more luminescence layers comprise a layer containing the blue phosphorescence material and a layer containing the green phosphorescence material and the red phosphorescence material; and
each of the two or more luminescence layers further contains a host material wherein the host material is different from the charge transporting material contained in the intermediate layer.
2. The organic electroluminescence device of claim 1 , wherein the intermediate layer is 0.1 to 10 nm in layer thickness.
3. The organic electroluminescence device of claim 1 , wherein the two or more luminescence layers comprise, in this order from an anode side, a layer containing a hole transporting host material having an ionization potential (Ip) of from 5.1 to 6.4 eV and an electron affinity (Ea) of from 1.2 to 3.1 eV and a layer containing an electron transporting host material having an ionization potential (Ip) of from 5.7 to 7.5 eV and an electron affinity (Ea) of from 2.5 to 3.5 eV.
4. The organic electroluminescence device of claim 1 , wherein the two or more luminescence layers comprise, in this order from an anode side, a layer containing a hole transporting host material having an ionization potential (Ip) of from 5.1 to 6.4 eV and an electron affinity (Ea) of from 1.2 to 3.1 eV and a layer containing an electron transporting luminescence material having an ionization potential (Ip) of from 5.7 to 7.0 eV and an electron affinity (Ea) of from 2.5 to 3.5 eV.
5. The organic electroluminescence device of claim 1 , wherein the blue phosphorescence material is contained in an amount of 10 to 25 mass % in the two or more luminescence layers, and the red phosphorescence material is contained in an amount of 0.2 to 5% by weight in the two or more luminescence layers.