Organic electroluminescence device

1. An organic electroluminescence device, comprising in sequential order an anode, an emitting layer, an electron transporting zone, and a cathode, wherein

the emitting layer comprises a host and a fluorescent dopant,

a triplet energy E T d (eV) of the fluorescent dopant is larger than a triplet energy E T h (eV) of the host,

the fluorescent dopant is a pyrene derivative,

a blocking layer is adjacent to the emitting layer in the electron transporting zone,

the blocking layer comprises an aromatic heterocyclic derivative,

a triplet energy E T b (eV) of the aromatic heterocyclic derivative is larger than a triplet energy E T h (eV) of the host, and

the aromatic heterocyclic derivative is represented by formula (BL-21):

wherein HAr independently represents a substituted or unsubstituted 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenyl group, 3-dibenzothiophenyl group, 4-dibenzothiophenyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group, 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group, 1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group, 2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group, 2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group, 2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group, 2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group, 2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group, 2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group, 2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group, 2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group, 2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group, 2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group, 10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group, 2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group, or 4-t-butyl-3-indolyl group, wherein if a plurality of HAr groups are present, the plurality of HAr groups may be the same or different;

L represents (i) a single bond, (ii) a divalent to tetravalent residue of a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, (iii) a divalent to tetravalent residue of a substituted or unsubstituted heterocyclic ring having 5 to 30 ring atoms, (iv) a divalent to tetravalent residue of a group in which two rings selected from the aromatic hydrocarbon ring and the heterocyclic ring are combined through a single bond; or (v) a divalent to tetravalent residue of a group in which three rings selected from the aromatic hydrocarbon ring and the heterocyclic ring are combined through single bonds;

a is an integer of 1 to 3;

b is an integer of 1 to 3; and

Az represents an azine ring represented by formula (BL-21-1):

wherein at least two X's are N and the rest of X is C(Ar);

Ar is a hydrogen atom, substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; and

at least one of Ar 1 , Ar 2 and Ar 3 is a single bond bonded to L in the formula (BL-21) and the rest of Ar 1 , Ar 2 , and Ar 3 not bonded to L in the formula (BL-21) is

a hydrogen atom,

a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,

a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or

a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

2. The organic electroluminescence device according to claim 1 , wherein

an electron mobility of the aromatic heterocyclic derivative is at least 10 −6 cm 2 /Vs in an electric field intensity of 0.04 MV/cm to 0.5 MV/cm.

3. The organic electroluminescence device according to claim 1 , wherein

the triplet energy E T b (eV) of the aromatic heterocyclic derivative and the triplet energy E T h (eV) of the host satisfy a relationship of E T h +0.2<E T b .

4. The organic electroluminescence device according to claim 1 , wherein

the electron transporting zone comprises an electron injecting layer.

5. The organic electroluminescence device according to claim 4 , wherein

the electron injecting layer comprises a material that has an electron mobility of at least 10 −6 cm 2 /Vs in an electric field intensity of 0.04 MV/cm to 0.5 MV/cm.

6. The organic electroluminescence device according to claim 4 , wherein the electron injecting layer and the blocking layer are formed of the same material.

7. The organic electroluminescence device according to claim 4 , wherein the electron injecting layer and the blocking layer are formed of the same material, and

the electron injecting layer is doped with a donor.

8. The organic electroluminescence device according to claim 4 , wherein the electron injecting layer is adjacent to the blocking layer.

9. The organic electroluminescence device according to claim 1 , wherein

the fluorescent dopant exhibits a fluorescent emission of a main peak wavelength of less than or equal to 550 nm.

10. The organic electroluminescence device according to claim 1 , wherein

a hole transporting zone is positioned between the anode and the emitting layer,

a hole transporting layer is adjacent to the emitting layer in the hole transporting zone, and

a triplet energy E T ho (eV) of the hole transporting layer is larger than the triplet energy E T h (eV) of the host.

11. The organic electroluminescence device according to claim 1 , wherein

the host is a compound that comprises a double bond only in a cyclic structure.

12. The organic electroluminescence device according to claim 1 , wherein

the fluorescent dopant is a compound that contains a double bond only in a cyclic structure.

13. An organic electroluminescence device, comprising in sequential order an anode, an emitting layer, an electron transporting zone, and a cathode, wherein

the emitting layer comprises a host and a fluorescent dopant,

the fluorescent dopant is a pyrene derivative,

a blocking layer is adjacent to the emitting layer in the electron transporting zone,

the blocking layer comprises an aromatic heterocyclic derivative,

a triplet energy E T b (eV) of the aromatic heterocyclic derivative is larger than a triplet energy E T h (eV) of the host,

a triplet energy E T d (eV) of the fluorescent dopant is larger than a triplet energy E T h (eV) of the host,

the aromatic heterocyclic derivative is represented by formula (BL-21):

wherein HAr independently represents a substituted or unsubstituted 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenyl group, 3-dibenzothiophenyl group, 4-dibenzothiophenyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group, 1 phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group, 1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group, 2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group, 2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group, 2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group, 2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group, 2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group, 2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group, 2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group, 2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group, 2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group, 2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group, 10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group, 2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group, or 4-t-butyl-3-indolyl group, wherein if a plurality of HAr groups are present, the plurality of HAr groups may be the same or different;

L represents (i) a single bond, (ii) a divalent to tetravalent residue of a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, (iii) a divalent to tetravalent residue of a substituted or unsubstituted heterocyclic ring having 5 to 30 ring atoms, (iv) a divalent to tetravalent residue of a group in which two rings selected from the aromatic hydrocarbon ring and the heterocyclic ring are combined through a single bond; or (v) a divalent to tetravalent residue of a group in which three rings selected from the aromatic hydrocarbon ring and the heterocyclic ring are combined-through single bonds;

a is an integer of 1 to 3;

b is an integer of 1 to 3; and

Az represents an azine ring represented by formula (BL-21-1):

wherein at least two X's are N and the rest of X is C(Ar);

Ar is a hydrogen atom, substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; and

at least one of Ar 1 , Ar 2 and Ar 3 is a single bond bonded to L in the formula (BL-21) and the rest of Ar 1 , Ar 2 , and Ar 3 not bonded to L in the formula (BL-21) is

a hydrogen atom,

a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,

a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or

a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, and

in applied voltage at the maximum current efficiency (cd/A), luminous intensity derived from singlet excitons generated by collision of triplet excitons generated in the emitting layer accounts for 30% or more of the entire luminous intensity.

14. The organic electroluminescence device according to claim 1 , wherein a main peak wavelength of the fluorescent dopant is 480 nm or less.

15. The organic electroluminescence device according to claim 1 , wherein HAr independently represents a substituted or unsubstituted 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenyl group, 3-dibenzothiophenyl group, 4-dibenzothiophenyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, or 9-carbazolyl group.

16. The organic electroluminescence device according to claim 13 , wherein HAr independently represents a substituted or unsubstituted 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenyl group, 3-dibenzothiophenyl group, 4-dibenzothiophenyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, or 9-carbazolyl group.

17. The organic electroluminescence device according to claim 1 , wherein

HAr represents a substituted or unsubstituted 9-carbazolyl group;

L represents a trivalent residue of a benzene ring which may be further optionally substituted;

a is 2,

b is 1,

Ar 1 is a single bond bonded to L,

Ar 2 is a biphenyl group, and

Ar 3 is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

18. The organic electroluminescence device according to claim 13 , wherein

HAr represents a substituted or unsubstituted 9-carbazolyl group;

L represents a trivalent residue of a benzene ring which may be further optionally substituted;

a is 2,

b is 1,

Ar 1 is a single bond bonded to L,

Ar 2 is a biphenyl group, and

Ar 3 is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.