Material for organic electroluminescence device and electroluminescence device
View Patent ↗Provided is a material for organic electroluminescence device containing (a) a phosphorescent metal complex containing a monoanionic bidentate ligand and a metal having an atomic weight of 40 or greater, wherein the monoanionic bidentate ligand is represented by the following formula (A): wherein, each of E 1a , E 1d , E 1e , E 1f , E 1k , E 1l , E 1p , and E 1q independently represents a carbon atom or a hetero atom, each of Z 1 , Z 2 , and Z 3 independently represents an aromatic ring or aromatic heterocycle, the aromatic ring or aromatic heterocycle may have a substituent, and a skeleton represented by the formula (A) has, in total, a 18π electron structure, and the bidentate ligand represented by the formula (A) may be coupled to another ligand to form a tridentate or higher-dentate ligand; and (b) a structural isomer represented by the same chemical formula as that of the phosphorescent metal complex (a) but different sterically in a coordination method of the ligand, wherein the structural isomer (b) is contained in an amount of 0.05 mass % or greater but not greater than 5 mass % relative to the phosphorescent metal complex (a).
1. A material for an organic electroluminescence device, which comprises:
(a) a phosphorescent metal complex represented by the following formula (A10-1):
wherein, each of R 1a to R 1i independently represents a hydrogen atom or a substituent, (b) a structural isomer represented by the same chemical formula as that of the phosphorescent metal complex (a) but different sterically in a coordination method of the ligand, wherein the structural isomer (b) is contained in an amount of 0.05 mass % or greater but not greater than 1 mass % relative to the phosphorescent metal complex (a), wherein the structural isomer of phosphorescent metal complex (a) is a facial isomer, while the structural isomer (b) is a meridional isomer.
2. The material for organic electroluminescence device according to claim 1 , wherein the phosphorescent metal complex represented by the formula (A10-1) is a phosphorescent metal complex represented by formula (A11-1)
wherein, each of R 1a , R 1b , R 1d , R 1e , R 1g , R 1h independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a cyano group, a fluoro group, —OR 2a , —SR 2a , —NR 2a R 2b , —BR 2a R 2b , or —SiR 2a R 2b R 2c , and each of R 2a to R 2c independently represents a hydrocarbon substituent or a heteroatom-substituted-substituent.
3. An organic electroluminescence device which comprises:
a substrate,
a pair of electrodes on the substrate,
and one or more organic layers including a light emitting layer between the electrodes,
wherein the material for organic electroluminescence device according to claim 1 is contained in at least one of the organic layers.
4. The organic electroluminescence device according to claim 3 , which comprises said material in the light emitting layer.
5. A light emission apparatus which comprises the organic electroluminescence device according to claim 3 .
6. A display apparatus which comprises the organic electroluminescence device according to claim 3 .
7. An illumination apparatus which comprises the organic electroluminescence device according to claim 3 .
8. The material for organic electroluminescence device according to claim 1 , wherein each of R 1a to R 1i independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a cyano group, a fluoro group, —OR 2a , —SR 2a , —NR 2a R 2b , —BR 2a R 2b , or —SiR 2a R 2b R 2c ,
wherein each of R 2a to R 2c independently represents an alkyl group, a cycloalkyl group, or an aryl group.
9. An organic electroluminescence device having a light emitting layer between a pair of electrodes, wherein the light emitting layer comprises:
(a) a phosphorescent metal complex represented by the following formula (A10-1):
wherein, each of R 1a to R 1i independently represents a hydrogen atom or a substituent, (b) a structural isomer represented by the same chemical formula as that of the phosphorescent metal complex (a) but different sterically in a coordination method of the ligand, wherein the structural isomer (b) is contained in an amount of 0.05 mass % or greater but not greater than 5 mass % relative to the phosphorescent metal complex (a), wherein the structural isomer of phosphorescent metal complex (a) is a facial isomer, while the structural isomer (b) is a meridional isomer;
wherein said device exhibits an improved brightness keeping ratio compared to a device comprising a phosphorescent metal complex represented by the same chemical formula as that of (A10-1) and having an amount of structural isomer (b) less than 0.05 mass % relative to the phosphorescent metal complex (a); and
the brightness keeping ratio is measured with respect to a storage condition of about 60° C. over about 24 hours.