Compound, charge transporting material and organic electroluminescent element
An object of the invention is to provide a charge transporting material having an excellent heat resistance, excellent filming properties, an excellent charge transporting ability, and excellent light-emitting characteristics and, also, to provide an organic electroluminescent element providing a high luminance and a highly luminous efficiency and having a long life. The invention relates to a charge transporting material comprising a compound having within the molecule two or more pyridine rings substituted at 2-, 4- and 6-positions thereof, which rings do not substantially conjugate each other (provided that the 3- and 5-positions of the pyridine rings may be substituted) and an organic electroluminescent element using the charge transporting material.
1. A charge transporting material comprising a compound having within the molecule two or more pyridine rings each substituted at least at 2-, 4- and 6-positions thereof by an aromatic ring group having a molecular weight of 400 or less, wherein the pyridine rings are connected to a connector having a molecular weight of 400 or less at the 4-position, and do not conjugate each other through the connector, and wherein the connector is a non-heterocyclic aromatic moiety.
2. The charge transporting material according to claim 1 , wherein the compound has within the molecule 2 to 8 pyridyl rings, and the substituents on each ring may be the same or different.
3. The charge transporting material according to claim 1 , wherein the molecular weight of the compound is from 200 to 4,000.
4. The charge transporting material according to claim 1 , wherein the compound does not have a diarylamine structure within the molecule.
5. The charge transporting material according to claim 1 , wherein the compound has at least one carbazole ring within the molecule.
6. The charge transporting material according to claim 1 , which is an electron transporting material.
7. An organic electroluminescent element comprising a substrate having provided on a substrate an anode, a cathode and an organic light-emitting layer between these electrodes and comprising the charge transporting material described in claim 1 .
8. The organic electroluminescent element according to claim 7 , wherein a layer comprising said charge transporting material is the organic light-emitting layer.
9. The organic electroluminescent element according to claim 8 , wherein the organic light-emitting layer comprises said charge transporting material as a host material, with the host material being doped with an organometallic complex.
10. The organic electroluminescent element according to claim 7 , wherein the organic light-emitting layer comprises an organometallic complex as a light-emitting dye, and a layer comprising said charge transporting material is a hole blocking layer provided in contact with the interface of the organic light-emitting layer on the cathode side.
11. The organic electroluminescent element according to claim 9 , wherein the organometallic complex has a 2-arylpyridine-based ligand.
12. The organic electroluminescent element according to claim 7 , wherein said charge transporting material is contained in both the organic light-emitting layer and the layer in contact with the interface of the organic light-emitting layer on the cathode side.
13. A compound represented by the following formula (III):
wherein ring C may have a substituent, the ring and optional substituent having a molecular weight of 400 or less, R 15 to R 18 each independently represents an aromatic ring group having a molecular weight of 400 or less, and two R 15 s to R 18 s in the formula (III) may be the same or different from each other.
14. A compound represented by the following formula (IV):
wherein X each represents —N═, and Y each represents —CH═, R 23 and R 24 each independently represents an arbitrary group, rings E 1 to E 3 may have a substituent in addition to R 23 and R 24 , plural R 23 s and R 29 s in the formula (IV) may be the same or different from each other, and ring D may have a substituent.