Organic electroluminescent element

1. An organic electroluminescent element comprising:

a pair of electrodes; and

an organic layer between the pair of electrodes, the organic layer comprising a light-emitting layer and an electron transporting layer,

wherein the light-emitting layer contains at least one phosphorescence-emitting material and at least one metal complex functioning as a host material, and the electron transporting layer contains a compound represented by the formula (E-I):

L A) m   (E-I)

wherein A represents a monovalent heterocyclic group wherein two or more aromatic hetero rings are condensed, the heterocyclic groups represented by A is the same or different from each other, m represents an integer of 2 or more, and L represents an m-valent linking group.

2. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-II):

wherein X represents O, S, Se, Te or N—R, R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, Q 2 represents atoms necessary for forming an aromatic hetero ring, m represents an integer of 2 or more, and L represents an m-valent linking group.

3. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-III):

wherein X represents O, S, Se, Te or N—R, R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, Q 3 represents atoms necessary for forming a nitrogen-containing aromatic hetero ring, m represents an integer of 2 or more, and L represents an m-valent linking group.

4. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-IV):

wherein X 4 represents O, S or N—R, R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, Q 4 represents atoms necessary for forming a 6-membered, nitrogen-containing aromatic hetero ring, m represents an integer of 2 to 8, and L represents an m-valent linking group.

5. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-V):

wherein R represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, Q 5 represents atoms necessary for forming a 6-membered, nitrogen-containing aromatic hetero ring, m represents an integer of from 2 to 8, and L represents an m-valent linking group.

6. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-VI):

wherein Q 61 , Q 62 and Q 63 each independently represents atoms necessary for forming a 6-membered, nitrogen-containing aromatic hetero ring, R 61 , R 62 and R 63 each independently represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, L 1 , L 2 and L 3 each independently represents a divalent linking group, and Y represents a nitrogen atom or a 1,3,5-benzenetriyl group.

7. The organic electroluminescent element according to claim 1 , wherein the compound of the formula (E-I) is a compound represented by the formula (E-VII):

wherein R 71 , R 72 and R 73 each independently represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group or a heterocyclic group, R 74 , R 75 and R 76 each independently represents a substituent, and p 1 , p 2 and p 3 each represents an integer of 0 to 3.

8. The organic electroluminescent element according to claim 1 , wherein the light-emitting layer is provided directly on the electron transporting layer.

9. The organic electroluminescent element according to claim 1 , wherein the metal complex is represented by the formula (H-4):

wherein X H41 and X H42 each independently represents a carbon atom or a nitrogen atom, the bond between X H41 and the nitrogen atom and the bond between X H42 and the carbon atom each independently represents a single bond or a double bond, Q H41 and Q H42 each independently represents atoms necessary for forming a 5- or 6-membered ring, M 4 represents a metal ion, n 4 represents an integer of 1 or more, L H represents a ligand, and m 4 represents an integer of 0 or more.

10. The organic electroluminescent element according to claim 1 , wherein the light-emitting layer contains from 50 to 99.9% by weight of the at least one metal complex.

11. The organic electroluminescent element according to claim 1 , wherein the light-emitting layer contains from 60 to 99% by weight of the at least one metal complex.

12. The organic electroluminescent element according to claim 1 , wherein the metal complex has a glass transition temperature of from 130 to 400° C.

13. The organic electroluminescent element according to claim 1 , wherein the metal complex is a complex of Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga or Ge.

14. The organic electroluminescent element according to claim 1 , wherein the metal complex is a complex of Li, Be, Na, Mg, Al, Ti, Fe, Co, Ni, Cu, Zn or Ga.

15. The organic electroluminescent element according to claim 1 , wherein the metal complex is a complex of Be, Mg, Al, Fe, Ni, Cu, Zn or Ga.

16. The organic electroluminescent element according to claim 1 , wherein the metal complex is a complex of Be, Mg, Al, Cu, Zn or Ga.

17. The organic electroluminescent element according to claim 1 , wherein the metal complex is a complex of Al or Zn.

18. The organic electroluminescent element according to claim 1 , wherein the phosphorescence-emitting material is a complex of iridium, platinum, rhenium or ruthenium.

19. The organic electroluminescent element according to claim 1 , wherein the phosphorescence-emitting material is a complex of iridium or platinum.

20. The organic electroluminescent element according to claim 1 , wherein the phosphorescence-emitting material is a complex of iridium.