Organic electroluminescent device

1. An organic electroluminescent device comprising:

a pair of electrodes; and

at least one organic compound layer between the pair of electrodes, the at least one organic compound layer including a light emitting layer,

wherein the light emitting layer contains at least one host material and at least one luminescent material that is a phosphorescent compound that emits light via a triplet excited state, and at least one host material is a compound represented by formula (V):

wherein X 51 represents a substituted nitrogen atom; X 52 represents a carbon atom that is present in a carbonylene group, an alkylene group or a group connected to X 51 to form a nitrogen containing-heterocyclic group; M 51 represents a metal ion; L 51 represents a ligand; m 51 represents an integer of 1 to 4; m 52 represents an integer of 0 to 6; and Q 51 represents a group necessary to form a nitrogen-containing heterocyclic ring.

2. The organic electroluminescent device of claim 1 , wherein the host material and the phosphorescent compound have a T 1 value of 60 kcal/mol or higher, and the phosphorescent compound emits phosphorescence having a peak wavelength of 550 nm or shorter.

3. The organic electroluminescent device of claim 1 , wherein the at least one organic compound layer is at least three organic compound layers including a hole transporting layer, a light emitting layer, and an electron transporting layer, and the electron transporting layer has an IP value of 5.9 eV or higher.

4. The organic electroluminescent device of claim 1 , wherein the at least one host material is a compound represented by the formula (IX):

wherein M 91 represents a metal ion; L 91 represents a ligand; m 91 represents an integer of 1 to 4; m 92 represents an integer of 0 to 6; Q 91 represents an atomic group necessary to form a nitrogen-containing heterocyclic ring; X 92 is a carbon atom; and Q 92 represents an atomic group necessary to form a nitrogen-containing heterocyclic ring.

5. The organic electroluminescent device of claim 1 , wherein the at least one host material is a compound represented by the formula (XI):

wherein M 111 represents a metal ion; L 111 represents a ligand; m 111 represents an integer of 1 to 4; m 112 represents an integer of 0 to 6; and R 111 , R 112 , R 113 , R 114 , R 115 , and R 116 each independently represent a hydrogen atom or a substituent.

6. The organic electroluminescent device of claim 1 , wherein the at least one host material is at least two host materials.

7. The organic electroluminescent device of claim 6 , wherein at least one of the host materials is an arylamine derivative.

8. The organic electroluminescent device of claim 6 , wherein at least one of the host materials is an aromatic hydrocarbon compound.

9. The organic electroluminescent device of claim 6 , wherein at least one of the host materials is an aromatic nitrogen-containing heterocyclic compound.

10. The organic electroluminescent device of claim 6 , wherein at least one of the host materials is a metal complex other than the compound represented by the formula (V).

11. The organic electroluminescent device of claim 1 , wherein the phosphorescent compound concentration in the light emitting layer is 0.1 to 50% by weight.

12. The organic electroluminescent device of claim 1 , wherein the phosphorescent compound concentration in the light emitting layer is 0.2 to 30% by weight.

13. The organic electroluminescent device of claim 1 , wherein the host material and the phosphorescent compound have a T 1 value of 65 kcal/mol or higher and the phosphorescent compound emits phosphorescence having a peak wavelength of 480 nm or shorter.

14. The organic electroluminescent device of claim 1 , wherein the organic electroluminescent device further comprises a layer containing a compound having an IP of 5.9 eV or higher between a cathode and the light emitting layer.

15. The organic electroluminescent device of claim 1 , wherein the thickness of each layer constituting the light emitting layer is 0.5 to 10 nm.