Organic electroluminescence element

1. An organic electroluminescence element comprising:

an anode;

a first emitting layer comprising at least a first host material and a first dopant;

a second emitting layer comprising at least a second host material and a second dopant;

an electron injecting layer; and

a cathode in the order mentioned,

wherein the energy gap E gh 1 of the first host material, the energy gap E gd 1 of the first dopant, the energy gap E gh 2 of the second host material, and the energy gap E gd 2 of the second dopant satisfy the following formulas [i] to [iv];

the luminescent intensity I 1 at the maximum luminescent wavelength of an emission spectrum derived from the first emitting layer, and the luminescent intensity I 2 at the maximum luminescent wavelength of an emission spectrum derived from the second emitting layer satisfy the following formula [v]; and

the electron mobility of the electron injecting layer is 10 −4 cm 2 /(V·sec) or more:

E gh 1>E gd 1  [i]

E gh 2>E gd 2  [ii]

E gh 1>E gd 2  [iii]

E gh 1>2.7eV  [iv]

I 1>3.5× I 2  [v].

2. An organic electroluminescence element according to claim 1 , wherein the following formula is satisfied:

I 1>5× I 2.

3. An organic electroluminescence element according to claim 1 , wherein E gd 2 is more than 2.7 eV.

4. An organic electroluminescence element according to claim 1 , wherein the ratio of the first dopant to the first host material is 0.1 to 10 mol % in the first emitting layer.

5. An organic electroluminescence element according to claim 1 , wherein the ratio of the second dopant to the second host material is 0.1 to 10 mol % in the second emitting layer.

6. An organic electroluminescence element according to claim 1 , wherein the first host material is the same as the second host material.

7. An organic electroluminescence element according to claim 1 , wherein the first emitting layer has a film thickness of 10 nm or more.

8. An organic electroluminescence element according to claim 1 , wherein the electron injecting layer comprises one or more organic compounds comprising a nitrogen-containing heterocyclic derivative.

9. An organic electroluminescence element according to claim 8 , wherein the organic compound(s) is/are an imidazopyrazine derivative and/or an imidazole derivative.

10. The organic electroluminescence element according to claim 1 , wherein at least one of the first host material and the second host material is a compound represented by a formula [1]:

wherein Ar 1 is an aromatic ring with 6 to 50 nucleus carbons, X is a substituent, m is an integer of 1 to 5 and n is an integer of 0 to 6, provided that when m is 2 or more, the plurality of Ar 1 may be the same as or different from each other, and when n is 2 or more, the plurality of Xs may be the same as or different from each other.

11. The organic electroluminescence element according to claim 10 , wherein Ar 1 is selected from the group consisting of phenyl, naphthyl, anthracene, acenaphthylene, fluorene, phenanthrene, fluoranthene, triphenylene, pyrene, chrysene, perylene, and trinaphthylene; and

X is selected from the group consisting of substituted or unsubstituted aromatic groups with 6 to 50 nucleus carbons, substituted or unsubstituted aromatic heterocyclic groups with 5 to 50 nucleus carbons, substituted or unsubstituted alkyl groups with 1 to 50 carbons, substituted or unsubstituted alkoxy groups with 1 to 50 carbons, substituted or unsubstituted aralkyl groups with 1 to 50 carbons, substituted or unsubstituted aryloxy groups with 5 to 50 nucleus atoms, substituted or unsubstituted arylthio groups with 5 to 50 nucleus atoms, substituted or unsubstituted carboxyl groups with 1 to 50 carbons, substituted or unsubstituted styryl groups, halogen groups, a cyano group, a nitro group, and a hydroxyl group.

12. The organic electroluminescence element according to claim 1 , wherein at least one of the first dopant and the second dopant is a compound represented by a formula [2]:

wherein each of Ar 2 to Ar 4 is a substituted or unsubstituted aromatic group with 6 to 50 nucleus carbons, or a substituted or unsubstituted styryl group; and p is an integer of 1 to 4; provided that when p is 2 or more, the plurality of Ar 3 and Ar 4 may be the same as or different from each other.

13. The organic electroluminescence element according to claim 12 , wherein each of Ar 2 to Ar 4 is selected from the group consisting of phenyl, 1-naphthyl, 2-naphthyl, 9-phenanthryl, 1-naphthacenyl, 2-naphthacenyl, 9-naphthacenyl, 1-pyrenyl, 2-pyrenyl, 4-pyrenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl, o-tolyl, m-tolyl, p-tolyl, p-t-butylphenyl, 2-fluorenyl, 9,9-dimethyl-2-fluorenyl, 3-fluoranthenyl, 2-phenyl-1-vinyl, 2,2-diphenyl-1-vinyl, and 1,2,2-triphenyl-1-vinyl.