Material for organic electroluminescence device, and organic electroluminescence device

1. A material for an organic electroluminescence device comprising at least a phosphorescent metal complex A and a phosphorescent metal complex B, wherein the phosphorescent metal complex A comprises a partial structure represented by the following formula (1), and the phosphorescent metal complex B has the same structure with the phosphorescent metal complex A except that, in at least one substituent of R 1 and R 2 in the formula (1), one or more atoms directly bonding to Q 1 or Q 2 are substituted with an atom belonging to the same group as in the one or more atoms and having a greater atomic weight than the one or more atoms, and a ratio of the content of the phosphorescent metal complex B to a content of the phosphorescent metal complex A is 0.005% by mass or more and 2% by mass or less:

wherein each of R 1 and R 2 independently represents a substituent; when a plurality of R 1 's are present, the R 1 's may be the same with or different from each other; when a plurality of R 2 's are present, the R 2 ′s may be the same with or different from each other; and the R 1 's and the R 2 's may be bonded to each other to form a ring; M represents a metal having an atomic weight of 40 or more; each of X 1 , X 2 and X 3 independently represents a carbon atom or a nitrogen atom, provided that all of X 1 , X 2 and X 3 do not represent a nitrogen atom; Q 1 represents a 5- or 6-membered aromatic heterocyclic ring; Q 2 represents a 5- or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring; each of n1 and n2 independently represents an integer of 0 to 4, but there is no case where the sum of n1 and n2 is 0; the bidentate ligand including Q 1 and Q 2 may form a tridentate or higher multidentate ligand by bonding to other ligands, and Q 1 and Q 2 may be linked via a linking group to form a ring.

2. The material for an organic electroluminescence device as claimed in claim 1 , wherein the metal complex A has at least one fluorine atom as at least one of R 1 and R 2 in formula (1), and the at least one fluorine atom of the metal complex A is replaced with at least one halogen atom other than the fluorine atom in the metal complex B.

3. The material for an organic electroluminescence device as claimed in claim 2 , wherein the halogen atom other than the fluorine atom in the metal complex B is a chlorine atom.

4. The material for an organic electroluminescence device as claimed in claim 1 , wherein both of R 1 and R 2 are fluorine atoms.

5. The material for an organic electroluminescence device as claimed in claim 1 , wherein the metal complex A comprises a partial structure represented by the following formula (2):

wherein M represents a metal having an atomic weight of 40 or more; X 2 represents a carbon atom or a nitrogen atom; Q 1 represents a 5- or 6-membered aromatic heterocyclic ring;

each of E 1 , E 2 and E 3 independently represents a carbon atom or a nitrogen atom, provided that all of E 1 , E 2 and E 3 do not represent a nitrogen atom; each of n1 and n2 independently represents an integer of 0 to 4, but there is no case where the sum of n1 and n2 is 0; and the bidentate ligand including ring Q 1 and the ring containing E 1 , E 2 and E 3 may form a tridentate or higher multidentate ligand by bonding to other ligands.

6. The material for an organic electroluminescence device as claimed in claim 1 , wherein the metal complex A comprising a partial structure represented by the following formula (3):

wherein M represents a metal having an atomic weight of 40 or more; E 3 represents a carbon atom or a nitrogen atom; n3 represents an integer of 1 to 4; and the bidentate ligand including pyridine and the ring containing E 3 may form a tridentate or higher multidentate ligand by bonding to other ligands.

7. The material for an organic electroluminescence device as claimed in claim 1 , wherein E 3 represents a carbon atom.

8. The material for an organic electroluminescence device as claimed in claim 1 , wherein M represents Pt.

9. The material for an organic electroluminescence device as claimed in claim 1 , wherein the formula (1) is represented by the following formula (C-2):

wherein L 21 represents a single bond or a divalent linking group; each of Z 21 and Z 22 independently represents a 5- or 6-membered nitrogen-containing aromatic heterocyclic ring;

each of Z 23 and Z 24 independently represents a benzene ring or a 5- or 6-membered aromatic heterocyclic ring; each of Z 21 and Z 23 may independently have 1 to 4 substituents, and these substituents may be bonded to each other to form a ring, provided that at least one of Z 21 and Z 23 has one or more substituents; each of Z 22 and Z 24 may have a substituent and these substituents may be bonded to each other to form a ring; and each of X 21 , X 22 , X 23 and X 24 independently represents a carbon atom or a nitrogen atom.

10. The material for an organic electroluminescence device as claimed in claim 1 , wherein M represents Ir.

11. The material for an organic electroluminescence device as claimed in claim 1 , wherein the formula (1) is represented by the following formula (A10):

wherein each of R 1a to R 1i independently represents a hydrogen atom or a substituent; X—Y represents a mono-anionic bidentate ligand; and n represents an integer of 1 to 3,

wherein at least one of R 1a , R 1b , R 1g R 1h or R 1i is a substituent.

12. The material for an organic electroluminescence device as claimed in claim 1 , wherein the formula (1) is represented by the following formula (P-1):

wherein each of R 1 and R 2 independently represents a substituent, and when a plurality of R 1 and R 2 are present, these R 1 and R 2 may be the same with or different from each other; each of n1 and n2 independently represents an integer of 0 to 4, but there is no case where the sum of n1 and n2 is 0; X—Y represents a mono-anionic bidentate ligand; and n represents an integer of 1 to 3.

13. An organic electroluminescence device comprising a substrate having thereon a pair of electrodes and at least one organic layer comprising a light-emitting layer comprising a light-emitting material between the pair of electrodes, wherein the light-emitting layer comprises the material for an organic electroluminescence device as claimed in claim 1 .

14. An organic electroluminescence device comprising a substrate having thereon a pair of electrodes and at least one organic layer comprising a light-emitting layer comprising a light-emitting material between the pair of electrodes, wherein at least any layer of the organic layers comprises the material for an organic electroluminescence device as claimed in claim 1 .

15. A light emission apparatus comprising the organic electroluminescence device as claimed in claim 14 .

16. A display apparatus comprising the organic electroluminescence device as claimed in claim 14 .

17. An illumination apparatus comprising the organic electroluminescence device as claimed in claim 14 .

18. A composition of a material for an organic electroluminescence device comprising at least a phosphorescent metal complex A and a phosphorescent metal complex B, wherein the phosphorescent metal complex A comprises a partial structure represented by the following formula (1), and the phosphorescent metal complex B has the same structure as the phosphorescent metal complex A except that, in at least one substituent of R 1 and R 2 in the formula (1), one or more atoms directly bonding to Q 1 or Q 2 are substituted with atoms belonging to the same group of the one or more atoms and having a greater atomic weight than the one or more atoms, and ratio of the content of the phosphorescent metal complex B to the content of phosphorescent the metal complex A is 0.005% by mass or more and 2% by mass or less:

wherein each of R 1 's and R 2 's independently represents a substituent, when a plurality of R 1 's and a plurality of R 2 's are present, the plurality of R 1 and R 2 may be the same with or different from each other, and the plurality of R 1 and R 2 may be bonded to each other to form a ring; M represents a metal having an atomic weight of 40 or more; each of X 1 , X 2 and X 3 independently represents a carbon atom or a nitrogen atom, provided that all of X 1 , X 2 and X 3 do not represent a nitrogen atom; Q 1 represents a 5- or 6-membered aromatic heterocyclic ring; Q 2 represents a 5- or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring; each of n1 and n2 independently represents an integer of 0 to 4, but there is no case where the sum of n1 and n2 is 0; the bidentate ligand including Q 1 and Q 2 may form a tridentate or higher multidentate ligand by bonding to other ligands, and Q 1 and Q 2 may be linked via a linking group to form a ring.

19. A light-emitting layer which comprises a material for an organic electroluminescence device comprising at least a phosphorescent metal complex A and a phosphorescent metal complex B, wherein the phosphorescent metal complex A comprises a partial structure represented by the following formula (1), and the phosphorescent metal complex B has the same structure with the phosphorescent metal complex A except that, in at least one substituent of R 1 and R 2 in the formula (1), one or more atoms directly bonding to Q 1 or Q 2 are substituted with atoms belonging to the same group of the one or more atoms and having a greater atomic weight than the one or more atoms, and a ratio of the content of the phosphorescent metal complex B to the content of the phosphorescent metal complex A is 0.005% by mass or more and 2% by mass or less:

wherein each of R 1 's and R 2 's independently represents a substituent, and when a plurality of R 1 's and a plurality of R 2 's are present, the plurality of R 1 and R 2 may be the same with or different from each other; M represents a metal having an atomic weight of 40 or more;

each of X 1 , X 2 and X 3 independently represents a carbon atom or a nitrogen atom, provided that all of X 1 , X 2 and X 3 do not represent a nitrogen atom; Q 1 represents a 5- or 6-membered aromatic heterocyclic ring; Q 2 represents a 5- or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring; each of n1 and n2 independently represents an integer of 0 to 4, but there is no case where the sum of n1 and n2 is 0; the bidentate ligand including Q 1 and Q 2 may form a tridentate or higher multidentate ligand by bonding to other ligands, and Q 1 and Q 2 may be linked via a linking group to form a ring.