# Patent

## Title
Light emitting material and light emitting device

## Abstract

Provided is a light emitting material of which a light emitting device having high luminous efficiency and high stability and capable of being provided at a low cost can be formed. A light emitting material includes the following partial structural formula (1):




wherein at least one of R1 to R10 represents a substituent except a hydrogen atom, a total number of benzene ring structures in R1 to R10 is 3 or more, and R1 to R10 include a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light emitting material and a light emitting device using an organic compound, and more specifically, to a light emitting device using a metal coordination compound as a light emitting material.
2. Description of the Related Art
Applied researches have been vigorously conducted on an organic electroluminescence (EL) device because of the potential of the device to function as a light emitting device having high-speed responsiveness and high luminous efficiency (Macromol. Symp., 1997, 125, 1-48). Among the research, a wide range of researches on an iridium metal coordination compound has been carried out because the compound can function as a light emitting material having high luminous efficiency and high stability when used in an organic EL device (Inorganic. Chemistry. 2001, 40, 1704-1711, Journal. American. Chemical. Society. 2001, 123, 4304-4312, International Publication No. 02/44189, and International Publication No. 03/91355).
Organic EL devices each using an iridium coordination compound as a phosphorescent dopant are roughly classified into two kinds: a device to be produced by a vacuum vapor deposition method (Inorganic. Chemistry. 2001, 40, 1704-1711, and Journal. American. Chemical. Society. 2001, 123, 4304-4312) and a device to be produced by applying a solution prepared by dissolving a predetermined amount of the compound in a solvent to an electrode substrate by, for example, a spin coating method, a printing method, or an ink-jet method (Applied Physics Letters 80, 2045-2047 (2002), and Journal of Polymer Science: Part B: Polymer Physics 41, 2681-2690 (2003)).
A research and development of a device to be produced by the vacuum vapor deposition method have progressed, and the device has a relatively high level of performance because the device has high luminous efficiency and high stability at the time of driving. On the other hand, as pointed out in Journal of Polymer Science: Part B: Polymer Physics 41, 2681-2690 (2003), a device to be produced by an application method cannot provide sufficient performance when the light emitting layer of the device is formed of two kinds of materials, that is, an iridium coordination compound and a host material. In other words, owing to, for example, a problem of compatibility between both materials and a difference in solubility in a solvent between the materials, a phenomenon such as the inhibition of light emission by the agglomeration of the iridium coordination compound in the device occurs, so the device is problematic in terms of luminous efficiency and stability at the time of driving, and hence cannot provide sufficient performance.
In addition, Journal. American. Chemical. Society. 2004, 126, 7041-7048 proposes a compound using an oligofluorenyl group, in which a fluorene group continues to Ir(ppy)2(acac) that emits green light or Ir(btp)2(acac) that emits red light in a linear fashion, as a substituent. However, the external quantum efficiency of a device using such compound is as low as 1.5% at best. In addition, an iridium coordination compound Ir(btp)2(acac) that is intrinsically unsubstituted has a luminous wavelength of 2 eV (620 nm), but providing the compound with an oligofluorenyl group shifts the luminous wavelength to about 1.8 eV or more to 1.9 eV or less (650 nm or more to 690 nm or less). An influence of the substituent increases the number of deactivation paths to reduce the luminous efficiency of the device. Moreover, the fact that the luminous wavelength shifts to the range of 1.8 eV or more to 1.9 eV or less (650 nm or more to 690 nm or less) where a human being shows weak red visual sensitivity is also a large factor for reducing the luminous efficiency.
Therefore, no phosphorescent dopant suitable for an application method has been heretofore found in red light emitting materials, and the development of such dopant has been an object.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a light emitting material of which a light emitting device having high luminous efficiency and high stability and capable of being provided at a low cost can be formed, and a light emitting device using the light emitting material.
That is, according to the present invention, there is provided a light emitting material including the following partial structural formula (1) is provided:




wherein at least one of R1 to R10 represents a substituent except a hydrogen atom, a total number of benzene ring structures in R1 to R10 is 3 or more, and R1 to R10 include a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.

According to the present invention, there is provided a light emitting device including at least two electrodes, and a light emitting layer interposed between the electrodes, in which the light emitting layer contains the light emitting material.
A light emitting device using the light emitting material of the present invention has high luminous efficiency, stably emits light, and is provided at a low cost.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B, and 1C are views showing the emission spectra of solutions of Exemplified Compounds 1014 to 1016 in toluene.



DESCRIPTION OF THE EMBODIMENTS
Hereinafter, the present invention will be described in detail.
First, the structure of an iridium coordination compound as a light emitting material of the present invention will be described.
Examples of the light emitting material of the present invention are shown below.
















As shown in the above exemplified compounds, the light emitting material of the present invention is roughly formed of two parts: an iridium(phenylisoquinoline) part represented by the above partial structural formula (1) and a part formed of R1 to R10 placed around the iridium(phenylisoquinoline) part. The light emitting material of the present invention has such a molecular structure that substituents R1 to R10 including plural aromatic rings and an alkyl group are placed around an iridium(phenylisoquinoline) skeleton. The importance of the molecular structure as a light emitting material will be described below.
(1) The solubility of the light emitting material in a general organic solvent improves when R1 to R10 include a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms. The production of a light emitting material having high solubility is indispensable to the production of an organic EL device by an application method. In a case where an EL device is produced by doping a carrier transportable host with the light emitting material of the present invention, when the host and the light emitting material largely differ from each other in solubility, there is a high possibility that the same kind of molecules agglomerate upon drying of a solution containing the host and the light emitting material after the application of the solution, so the quality of a film formed of the solution may deteriorate, or the performance of the device may reduce. It is important to impart sufficient solubility to each of the host and the light emitting material in order to avoid the foregoing phenomenon. Investigation conducted by the inventors of the present invention has revealed that sufficient solubility can be obtained when “R1 to R10 include a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms.”
(2) A substituent is introduced in such a manner that “the total number of benzene ring structures in R1 to R10 is 3 or more.” The introduction of “a substituent including 3 or more benzene ring structures into any one of R1 to R10” is desirable. As a result, the iridium(phenylisoquinoline) part as a light emitting center is protected from its surroundings, whereby the production of a quenching path due to an intermolecular interaction is suppressed. In particular, a light emitting site density substantially reduces, so the concentration quenching of the light emitting material can be dissolved, and high luminous efficiency can be realized even when the concentration of the light emitting material is high. In general, a light emitting layer is formed of two components, that is, a host and a light emitting material in order that the concentration quenching of the light emitting material may be suppressed; in the case of the light emitting material (iridium coordination compound) of the present invention, a light emitting layer can be formed only of the light emitting material.
(3) Substituent sites including 3 or more benzene ring structures in R1 to R10 each have high carrier transporting property. In such case, the iridium coordination compound of the present invention is a multifunctional light emitting material bringing together carrier transporting property and strong light emitting characteristics.
(4) Iridium(phenylisoquinoline) as a light emitting center is a red phosphorescence emitting center. Unsubstituted Ir(piq)3 is a red light emitting material having a luminous wavelength of 620 nm; the light emission peak wavelength of the material fluctuates depending on a substituent, and the material emits red phosphorescence having a peak at a wavelength of 600 nm or more to 650 nm or less with high efficiency. When a substituent including 3 or more benzene ring structures is introduced into the iridium coordination compound of the present invention, it is important for the substituent not to inhibit the emission of red phosphorescence. The case where the substituent receives the light emission energy of the iridium(phenylisoquinoline) site by energy transfer is not preferable because light emitted from the iridium(phenylisoquinoline) site is quenched. It is desirable that a substituent of the present invention neither absorb the light emission energy of the iridium(phenylisoquinoline) site nor inhibit the emission of red phosphorescence.
(5) When an aromatic ring group is directly bonded to the iridium(phenylisoquinoline) site, the π-electron conjugated system of the entire ligands expands, so light emission energy may reduce (the luminous wavelength of the light emitting material may lengthen). When the luminous wavelength becomes excessively long (650 nm or more), the material cannot be a preferable red light emitting material because the visual sensitivity of a human being to the wavelength reduces. In this case, the luminous wavelength must be shortened. Investigation conducted by the inventors of the present invention has revealed that the luminous wavelength can be shortened by introducing an electron-withdrawing substituent into any one of the substituents R1 to R4 on the phenyl group side of the iridium(phenylisoquinoline) site. An F atom, a trifluoromethyl group, a trifluoromethoxy group, or the like is effective in shortening the luminous wavelength, and any such substituent can be appropriately introduced according to the luminous wavelength.
Desirable examples of the light emitting material of the present invention include compounds each represented by the following structural formula (2) or (3).




Q1 and Q2 may be bonded to each other, and are each selected form the following structural formulae (4):




wherein R11 to R14 each represent a hydrogen atom, an alkyl group, or a substituent having 3 or more benzene ring structures, and R15 represents an alkyl or alkoxyl group having 1 or more to 5 or less carbon atoms, or a phenyl group which may be substituted by an alkyl or alkoxyl group that has 1 or more to 5 or less carbon atoms and that may be substituted by a halogen atom.

A compound in which at least one of R1 to R10 includes a structure represented by any one of the following partial structural formulae (5) to (7) can also be given as a desirable example.




R20 and R21 are each independently selected from a trifluoromethyl group, or a linear, branched, or cyclic alkyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.




At least one of R31 to R35 is a trifluoromethyl group, or a linear, branched, or cyclic alkyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.




At least one of R41 to R45 or R51 to R54 is a trifluoromethyl group, or a linear, branched, or cyclic alkyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.
Also, a compound which includes a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group in R1 to R4 can be a desirable example.
It is desirable that the light emitting material emit red light having a light emission peak at a wavelength of 600 nm or more to 650 nm or less. Further, the light emitting material has another light emission peak at a wavelength of 400 nm or more to 600 nm or less.
Further examples of the light emitting material of the present invention are shown below.

















































Further, examples of the light emitting material of the present invention are shown in the following tables. In the following tables, the name of a substituent including a fluorenyl group is represented by combining an abbreviated name shown in any one of 1FL1 to 1FL6, 2FL1 to 2FL7, 3FL1 to 3FL6, 4FL1 to 4FL6, 5FL1 to 5FL6 and 10FL1 to 20FL6 and the abbreviated name of a linking group shown in C1 to C11. In addition, the abbreviated name of an addition ligand represents a structure shown in acac to pic.






















The symbol “nFL” above represents an abbreviated name shown in any one of 1FL1 to 1FL6, 2FL1 to 2FL7, 3FL1 to 3FL6 and 4FL1 to 4FL6. That is, in the case of, for example, any one of the above exemplified compounds, the abbreviated name of a substituent including a fluorenyl group is as described below.
Exemplified Compound 1001: C1-3FL2
Exemplified Compound 1002: C2-3FL2
Exemplified Compound 1003: C8-3FL3
Exemplified Compound 1004: C1-4FL2
Exemplified Compound 1005: C1-4FL1
Exemplified Compound 1006: C1-3FL2
Exemplified Compound 1007: C10-3FL2
Therefore, the structures of those exemplified compounds are as shown in the following Table 1. It should be noted that, when the column of any one of R1 to R10 in the following table is blank, the one of R1 to R10 represents a hydrogen atom.
Other examples of the light emitting material of the present invention are shown in Tables 2 to 14.



















TABLE 1





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand






















1001
3


C1-3FL2





1002
3


C2-3FL2


1003
3


C8-3FL3


1004
3


C1-4FL2
Cyclohexyl


1005
3


C1-4FL1
C6H13—


1006
2

CH3O—
C1-3FL2


acac


1007
3


C10-3FL2




























TABLE 2





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand






















2001
3

C1-1FL1

C1-1FL1




2002
3

C1-1FL2

C1-1FL2


2003
3

C1-1FL3

C1-1FL3


2004
3

C1-1FL4

C1-1FL4


2005
3

C1-1FL5

C1-1FL5


2006
3

C1-1FL6

C1-1FL6


2007
3

C2-1FL1

C2-1FL1


2008
3

C3-1FL1

C3-1FL1


2009
3

C4-1FL1

C4-1FL1


2010
3

C5-1FL1

C5-1FL1


2011
3

C6-1FL1

C6-1FL1


2012
3

C7-1FL1

C7-1FL1


2013
3

C8-1FL1

C8-1FL1


2014
3

C9-1FL1

C9-1FL1


2015
3

C10-1FL1

C10-1FL1


2016
3

C11-1FL1

C11-1FL1


2017
3


C1-1FL1
C1-1FL1


2018
3


C1-1FL2
C1-1FL2


2019
3


C1-1FL3
C1-1FL3


2020
3


C1-1FL4
C1-1FL4


2021
3


C1-1FL5
C1-1FL5


2022
3


C1-1FL6
C1-1FL6


2023
3


C2-1FL1
C2-1FL1


2024
3


C3-1FL1
C3-1FL1


2025
3


C4-1FL1
C4-1FL1


2026
3


C5-1FL1
C5-1FL1


2027
3


C6-1FL1
C6-1FL1


2028
3


C7-1FL1
C7-1FL1


2029
3


C8-1FL1
C8-1FL1


2030
3


C9-1FL1
C9-1FL1


2031
3


C10-1FL1
C10-1FL1


2032
3


C11-1FL1
C11-1FL1


2033
3


C1-1FL1

C1-1FL1


2034
3


C1-1FL2

C1-1FL2


2035
3


C1-1FL3

C1-1FL3


2036
3


C1-1FL4

C1-1FL4


2037
3


C1-1FL5

C1-1FL5


2038
3


C1-1FL6

C1-1FL6


2039
3


C2-1FL1

C2-1FL1


2040
3


C3-1FL1

C3-1FL1


2041
3


C4-1FL1

C4-1FL1


2042
3


C5-1FL1

C5-1FL1


2043
3


C6-1FL1

C6-1FL1


2044
3


C7-1FL1

C7-1FL1


2045
3


C8-1FL1

C8-1FL1


2046
3


C9-1FL1

C9-1FL1


2047
3


C10-1FL1

C10-1FL1


2048
3


C11-1FL1

C11-1FL1


2049
2


C1-1FL1
C1-1FL1

acac


2050
2


C1-1FL2
C1-1FL2

acac


2051
2


C1-1FL3
C1-1FL3

acac


2052
2


C1-1FL4
C1-1FL4

acac


2053
2


C1-1FL5
C1-1FL5

acac


2054
2


C1-1FL6
C1-1FL6

acac


2055
2


C2-1FL1
C2-1FL1

acac


2056
2


C3-1FL1
C3-1FL1

acac


2057
2


C4-1FL1
C4-1FL1

acac


2058
2


C5-1FL1
C5-1FL1

acac


2059
2


C6-1FL1
C6-1FL1

acac


2060
2


C7-1FL1
C7-1FL1

acac


2061
2


C8-1FL1
C8-1FL1

acac


2062
2


C9-1FL1
C9-1FL1

acac


2063
2


C10-1FL1
C10-1FL1

acac


2064
2


C11-1FL1
C11-1FL1

acac


2065
3

F
C1-1FL1
C1-1FL1


2066
3

CH3O
C1-1FL1
C1-1FL1


2067
3

F
C2-1FL1
C2-1FL1


2068
3

CH3O
C2-1FL1
C2-1FL1




























TABLE 3





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







3001
3

C1-2FL1











3002
3

C1-2FL2


3003
3

C1-2FL3


3004
3

C1-2FL4


3005
3

C1-2FL5


3006
3

C1-2FL6


3007
3

C1-2FL7


3008
3

C2-2FL1


3009
3

C3-2FL1


3010
3

C4-2FL1


3011
3

C5-2FL1


3012
3

C6-2FL1


3013
3

C7-2FL1


3014
3

C8-2FL1


3015
3

C9-2FL1


3016
3

C10-2FL1


3017
3

C11-2FL1


3018
3


C1-2FL1


3019
3


C1-2FL2


3020
3


C1-2FL3


3021
3


C1-2FL4


3022
3


C1-2FL5


3023
3


C1-2FL6


3024



C1-2FL7


3025
3


C2-2FL1


3026
3


C3-2FL1


3027
3


C4-2FL1


3028
3


C5-2FL1


3029
3


C6-2FL1


3030
3


C7-2FL1


3031
3


C8-2FL1


3032
3


C9-2FL1


3033
3


C10-2FL1


3034
3


C11-2FL1


3035
3







C1-2FL1


3036
3







C1-2FL2


3037
3







C1-2FL3




























TABLE 4





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







3038
3







C1-2FL4





3039
3







C1-2FL5


3040
3







C1-2FL6


3041
3







C1-2FL7


3042
3







C2-2FL1


3043
3







C3-2FL1


3044
3







C4-2FL1


3045
3







C5-2FL1


3046
3







C6-2FL1


3047
3







C7-2FL1


3048
3







C8-2FL1


3049
3







C9-2FL1


3050
3







C10-2FL1


3051
3







C11-2FL1


3052
2


C1-2FL1







acac


3053
2


C1-2FL2







acac


3054
2


C1-2FL3







acac


3055
2


C1-2FL4







acac


3056
2


C1-2FL5







acac


3057
2


C1-2FL6







acac


3058
2


C1-2FL7







acac


3059
2


C2-2FL1







acac


3060
2


C3-2FL1







acac


3061
2


C4-2FL1







acac


3062
2


C5-2FL1







acac


3063
2


C6-2FL1







acac


3064
2


C7-2FL1







acac


3065
2


C8-2FL1







acac


3066
2


C9-2FL1







acac


3067
2


C10-2FL1







acac


3068
2


C11-2FL1







acac


3069
3

F
C2-2FL1


3070
3

CH3O
C2-2FL1


3071
3

F
C2-1FL1


3072
3

CH3O
C2-1FL1


3073
3


C2-2FL1





F


3074
3


C2-2FL1





Cyclohexyl


3075
3


C2-1FL1





F


3076
3


C2-1FL1





Cyclohexyl




























TABLE 5





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







4001
3

C1-3FL1











4002
3

C1-3FL2


4003
3

C1-3FL3


4004
3

C1-3FL4


4005
3

C1-3FL5


4006
3

C1-3FL6


4007
3

C2-3FL1


4008
3

C2-3FL2


4009
3

C2-3FL3


4010
3

C2-3FL4


4011
3

C2-3FL5


4012
3

C2-3FL6


4013
3

C3-3FL1


4014
3

C3-3FL2


4015
3

C3-3FL3


4016
3

C3-3FL4


4017
3

C3-3FL5


4018
3

C3-3FL6


4019
3

C3-3FL1


4020
3

C3-3FL2


4021
3

C3-3FL3


4022
3

C3-3FL4


4023
3

C3-3FL5


4024
3

C3-3FL6


4025
3

C8-3FL1


4026
3

C8-3FL2


4027
3

C8-3FL3


4028
3

C8-3FL4


4029
3

C8-3FL5


4030
3

C8-3FL6


4031
3

C10-3FL1


4032
3

C10-3FL2


4033
3

C10-3FL3


4034
3

C10-3FL4


4035
3

C10-3FL5


4036
3

C10-3FL6


4037
3


C1-3FL1


4038
3


C1-3FL2


4039
3


C1-3FL3


4040
3


C1-3FL4


4041
3


C1-3FL5


4042
3


C1-3FL6


4043
3


C2-3FL1


4044
3


C2-3FL2


4045
3


C2-3FL3


4046
3


C2-3FL4


4047
3


C2-3FL5


4048
3


C2-3FL6


4049
3


C3-3FL1


4050
3


C3-3FL2


4051
3


C3-3FL3


4052
3


C3-3FL4


4053
3


C3-3FL5


4054
3


C3-3FL6


4055
3


C3-3FL1


4056
3


C3-3FL2


4057
3


C3-3FL3


4058
3


C3-3FL4


4059
3


C3-3FL5


4060
3


C3-3FL6




























TABLE 6





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







4061
3


C8-3FL1










4062
3


C8-3FL2


4063
3


C8-3FL3


4064
3


C8-3FL4


4065
3


C8-3FL5


4066
3


C8-3FL6


4067
3


C10-3FL1


4068
3


C10-3FL2


4069
3


C10-3FL3


4070
3


C10-3FL4


4071
3


C10-3FL5


4072
3


C10-3FL6


4073
3

C1-3FL1






C6H13


4074
3

C1-3FL1






CH3


4075
3

C1-3FL1






CH3O


4076
3

C1-3FL1






F


4077
3

C1-3FL1






Cyclohexyl


4078
3

C1-3FL1
F


4079
3

C1-3FL1
CH3


4080
3

C1-3FL1
OCH3


4081
3

C1-3FL2






C6H13


4082
3

C1-3FL2






CH3


4083
3

C1-3FL2






CH3O


4084
3

C1-3FL2






F


4085
3

C1-3FL2






Cyclohexyl


4086
3

C1-3FL2
F


4087
3

C1-3FL2
CH3


4088
3

C1-3FL2
OCH3


4089
3

C2-3FL1






C6H13


4090
3

C2-3FL1






CH3


4091
3

C2-3FL1






CH3O


4092
3

C2-3FL1






F


4093
3

C2-3FL1






Cyclohexyl


4094
3

C2-3FL1
F


4095
3

C2-3FL1
CH3


4096
3

C2-3FL1
OCH3


4097
3

C2-3FL2






C6H13


4098
3

C2-3FL2






CH3


4099
3

C2-3FL2






CH3O


4100
3

C2-3FL2






F


4101
3

C2-3FL2






Cyclohexyl


4102
3

C2-3FL2
F


4103
3

C2-3FL2
CH3


4104
3

C2-3FL2
OCH3


4105
3

C10-3FL1






C6H13


4106
3

C10-3FL1






CH3


4107
3

C10-3FL1






CH3O


4108
3

C10-3FL1






F


4109
3

C10-3FL1






Cyclohexyl


4110
3

C10-3FL1
F


4111
3

C10-3FL1
CH3


4112
3

C10-3FL1
OCH3


4113
3

C10-3FL2






C6H13


4114
3

C10-3FL2






CH3


4115
3

C10-3FL2






CH3O


4116
3

C10-3FL2






F


4117
3

C10-3FL2






Cyclohexyl


4118
3

C10-3FL2
F


4119
3

C10-3FL2
CH3


4120
3

C10-3FL2
OCH3




























TABLE 7





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







4121
3


C1-3FL1





C6H13




4122
3


C1-3FL1





CH3


4123
3


C1-3FL1





CH3O


4124
3


C1-3FL1





F


4125
3


C1-3FL1





Cyclohexyl


4126
3

F
C1-3FL1


4127
3

CH3
C1-3FL1


4128
3

OCH3
C1-3FL1


4129
3


C1-3FL2





C6H13


4130
3


C1-3FL2





CH3


4131
3


C1-3FL2





CH3O


4132
3


C1-3FL2





F


4133
3


C1-3FL2





Cyclohexyl


4134
3

F
C1-3FL2


4135
3

CH3
C1-3FL2


4136
3

OCH3
C1-3FL2


4137
3


C2-3FL1





C6H13


4138
3


C2-3FL1





CH3


4139
3


C2-3FL1





CH3O


4140
3


C2-3FL1





F


4141
3


C2-3FL1





Cyclohexyl


4142
3

F
C2-3FL1


4143
3

CH3
C2-3FL1


4144
3

OCH3
C2-3FL1


4145
3


C2-3FL2





C6H13


4146
3


C2-3FL2





CH3


4147
3


C2-3FL2





CH3O


4148
3


C2-3FL2





F


4149
3


C2-3FL2





Cyclohexyl


4150
3

F
C2-3FL2


4151
3

CH3
C2-3FL2


4152
3

OCH3
C2-3FL2


4153
3


C10-3FL1





C6H13


4154
3


C10-3FL1





CH3


4155
3


C10-3FL1





CH3O


4156
3


C10-3FL1





F


4157
3


C10-3FL1





Cyclohexyl


4158
3

F
C10-3FL1


4159
3

CH3
C10-3FL1


4160
3

OCH3
C10-3FL1


4161
3


C10-3FL2





C6H13


4162
3


C10-3FL2





CH3


4163
3


C10-3FL2





CH3O


4164
3


C10-3FL2





F


4165
3


C10-3FL2





Cyclohexyl


4166
3

F
C10-3FL2


4167
3

CH3
C10-3FL2


4168
3

OCH3
C10-3FL2


4169
2

C1-3FL1








acac


4170
2

C1-3FL2








acac


4171
2

C1-3FL3








acac


4172
2

C1-3FL4








acac


4173
2

C1-3FL5








acac


4174
2

C1-3FL6








acac


4175
2

C2-3FL1








acac


4176
2

C2-3FL2








acac


4177
2

C2-3FL3








acac


4178
2

C2-3FL4








acac


4179
2

C2-3FL5








acac


4180
2

C2-3FL6








acac




























TABLE 8





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







4181
2

C3-3FL1








acac


4182
2

C3-3FL2








acac


4183
2

C3-3FL3








acac


4184
2

C3-3FL4








acac


4185
2

C3-3FL5








acac


4186
2

C3-3FL6








acac


4187
2

C3-3FL1








pic


4188
2

C3-3FL2








pic


4189
2

C3-3FL3








pic


4190
2

C3-3FL4








pic


4191
2

C3-3FL5








pic


4192
2

C3-3FL6








pic


4193
2

C8-3FL1








pic


4194
2

C8-3FL2








pic


4195
2

C8-3FL3








pic


4196
2

C8-3FL4








pic


4197
2

C8-3FL5








pic


4198
2

C8-3FL6








pic


4199
2

C10-3FL1








pic


4200
2

C10-3FL2








pic


4201
2

C10-3FL3








pic


4202
2

C10-3FL4








pic


4203
2

C10-3FL5








pic


4204
2

C10-3FL6








pic


4205
2

C1-3FL1








dpm


4206
2

C1-3FL1








acac-3FL1


4207
2

C1-3FL1








acac-4FL1


4208
2

C1-3FL1








dpm


4209
2

C1-3FL1








dpm


4210
2


C1-3FL1





C6H13

acac


4211
2


C1-3FL1





CH3

acac


4212
2


C1-3FL1





CH3O

acac


4213
2


C1-3FL1





F

acac


4214
2


C1-3FL1





Cyclohexyl

acac


4215
2

F
C1-3FL1







acac


4216
2

CH3
C1-3FL1







acac


4217
2

OCH3
C1-3FL1







acac


4218
2


C1-3FL2





C6H13

acac


4219
2


C1-3FL2





CH3

acac


4220
2


C1-3FL2





CH3O

acac


4221
2


C1-3FL2





F

acac


4222
2


C1-3FL2





Cyclohexyl

acac


4223
2

F
C1-3FL2







acac


4224
2

CH3
C1-3FL2







acac


4225
2

OCH3
C1-3FL2







acac


4226
3








C1-3FL1


4227
3








C1-3FL2


4228
3








C1-3FL3


4229
3








C1-3FL4


4230
3








C1-3FL5


4231
3








C1-3FL6


4232
3








C2-3FL1


4233
3








C2-3FL2


4234
3








C2-3FL3


4235
3








C2-3FL4


4236
3








C2-3FL5


4237
3








C2-3FL6




























TABLE 9





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







5001
3

C1-4FL1











5002
3

C1-4FL2


5003
3

C1-4FL3


5004
3

C1-4FL4


5005
3

C1-4FL5


5006
3

C1-4FL6


5007
3

C2-4FL1


5008
3

C2-4FL2


5009
3

C2-4FL3


5010
3

C2-4FL4


5011
3

C2-4FL5


5012
3

C2-4FL6


5013
3

C3-4FL1


5014
3

C3-4FL2


5015
3

C3-4FL3


5016
3

C3-4FL4


5017
3

C3-4FL5


5018
3

C3-4FL6


5019
3

C3-4FL1


5020
3

C3-4FL2


5021
3

C3-4FL3


5022
3

C3-4FL4


5023
3

C3-4FL5


5024
3

C3-4FL6


5025
3

C8-4FL1


5026
3

C8-4FL2


5027
3

C8-4FL3


5028
3

C8-4FL4


5029
3

C8-4FL5


5030
3

C8-4FL6


5031
3

C10-4FL1


5032
3

C10-4FL2


5033
3

C10-4FL3


5034
3

C10-4FL4


5035
3

C10-4FL5


5036
3

C10-4FL6


5037
3


C1-4FL1


5038
3


C1-4FL2


5039
3


C1-4FL3


5040
3


C1-4FL4


5041
3


C1-4FL5


5042
3


C1-4FL6


5043
3


C2-4FL1


5044
3


C2-4FL2


5045
3


C2-4FL3


5046
3


C2-4FL4


5047
3


C2-4FL5


5048
3


C2-4FL6


5049
3


C3-4FL1


5050
3


C3-4FL2


5051
3


C3-4FL3


5052
3


C3-4FL4


5053
3


C3-4FL5


5054
3


C3-4FL6


5055
3


C3-4FL1


5056
3


C3-4FL2


5057
3


C3-4FL3


5058
3


C3-4FL4


5059
3


C3-4FL5


5060
3


C3-4FL6




























TABLE 10





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







5061
3


C8-4FL1










5062
3


C8-4FL2


5063
3


C8-4FL3


5064
3


C8-4FL4


5065
3


C8-4FL5


5066
3


C8-4FL6


5067
3


C10-4FL1


5068
3


C10-4FL2


5069
3


C10-4FL3


5070
3


C10-4FL4


5071
3


C10-4FL5


5072
3


C10-4FL6


5073
3

C1-4FL1






C6H13


5074
3

C1-4FL1






CH3


5075
3

C1-4FL1






CH3O


5076
3

C1-4FL1






F


5077
3

C1-4FL1






Cyclohexyl


5078
3

C1-4FL1
F


5079
3

C1-4FL1
CH3


5080
3

C1-4FL1
OCH3


5081
3

C1-4FL2






C6H13


5082
3

C1-4FL2






CH3


5083
3

C1-4FL2






CH3O


5084
3

C1-4FL2






F


5085
3

C1-4FL2






Cyclohexyl


5086
3

C1-4FL2
F


5087
3

C1-4FL2
CH3


5088
3

C1-4FL2
OCH3


5089
3

C2-4FL1






C6H13


5090
3

C2-4FL1






CH3


5091
3

C2-4FL1






CH3O


5092
3

C2-4FL1






F


5093
3

C2-4FL1






Cyclohexyl


5094
3

C2-4FL1
F


5095
3

C2-4FL1
CH3


5096
3

C2-4FL1
OCH3


5097
3

C2-4FL2






C6H13


5098
3

C2-4FL2






CH3


5099
3

C2-4FL2






CH3O


5100
3

C2-4FL2






F


5101
3

C2-4FL2






Cyclohexyl


5102
3

C2-4FL2
F


5103
3

C2-4FL2
CH3


5104
3

C2-4FL2
OCH3


5105
3

C10-4FL1






C6H13


5106
3

C10-4FL1






CH3


5107
3

C10-4FL1






CH3O


5108
3

C10-4FL1






F


5109
3

C10-4FL1






Cyclohexyl


5110
3

C10-4FL1
F


5111
3

C10-4FL1
CH3


5112
3

C10-4FL1
OCH3


5113
3

C10-4FL2






C6H13


5114
3

C10-4FL2






CH3


5115
3

C10-4FL2






CH3O


5116
3

C10-4FL2






F


5117
3

C10-4FL2






Cyclohexyl


5118
3

C10-4FL2
F


5119
3

C10-4FL2
CH3


5120
3

C10-4FL2
OCH3




























TABLE 11





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







5121
3


C1-4FL1





C6H13




5122
3


C1-4FL1





CH3


5123
3


C1-4FL1





CH3O


5124
3


C1-4FL1





F


5125
3


C1-4FL1





Cyclohexyl


5126
3

F
C1-4FL1


5127
3

CH3
C1-4FL1


5128
3

OCH3
C1-4FL1


5129
3


C1-4FL2





C6H13


5130
3


C1-4FL2





CH3


5131
3


C1-4FL2





CH3O


5132
3


C1-4FL2





F


5133
3


C1-4FL2





Cyclohexyl


5134
3

F
C1-4FL2


5135
3

CH3
C1-4FL2


5136
3

OCH3
C1-4FL2


5137
3


C2-4FL1





C6H13


5138
3


C2-4FL1





CH3


5139
3


C2-4FL1





CH3O


5140
3


C2-4FL1





F


5141
3


C2-4FL1





Cyclohexyl


5142
3

F
C2-4FL1


5143
3

CH3
C2-4FL1


5144
3

OCH3
C2-4FL1


5145
3


C2-4FL2





C6H13


5146
3


C2-4FL2





CH3


5147
3


C2-4FL2





CH3O


5148
3


C2-4FL2





F


5149
3


C2-4FL2





Cyclohexyl


5150
3

F
C2-4FL2


5151
3

CH3
C2-4FL2


5152
3

OCH3
C2-4FL2


5153
3


C10-4FL1





C6H13


5154
3


C10-4FL1





CH3


5155
3


C10-4FL1





CH3O


5156
3


C10-4FL1





F


5157
3


C10-4FL1





Cyclohexyl


5158
3

F
C10-4FL1


5159
3

CH3
C10-4FL1


5160
3

OCH3
C10-4FL1


5161
3


C10-4FL2





C6H13


5162
3


C10-4FL2





CH3


5163
3


C10-4FL2





CH3O


5164
3


C10-4FL2





F


5165
3


C10-4FL2





Cyclohexyl


5166
3

F
C10-4FL2


5167
3

CH3
C10-4FL2


5168
3

OCH3
C10-4FL2


5169
2

C1-4FL1








acac


5170
2

C1-4FL2








acac


5171
2

C1-4FL3








acac


5172
2

C1-4FL4








acac


5173
2

C1-4FL5








acac


5174
2

C1-4FL6








acac


5175
2

C2-4FL1








acac


5176
2

C2-4FL2








acac


5177
2

C2-4FL3








acac


5178
2

C2-4FL4








acac


5179
2

C2-4FL5








acac


5180
2

C2-4FL6








acac




























TABLE 12





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







5181
2

C3-4FL1








acac


5182
2

C3-4FL2








acac


5183
2

C3-4FL3








acac


5184
2

C3-4FL4








acac


5185
2

C3-4FL5








acac


5186
2

C3-4FL6








acac


5187
2

C3-4FL1








pic


5188
2

C3-4FL2








pic


5189
2

C3-4FL3








pic


5190
2

C3-4FL4








pic


5191
2

C3-4FL5








pic


5192
2

C3-4FL6








pic


5193
2

C8-4FL1








pic


5194
2

C8-4FL2








pic


5195
2

C8-4FL3








pic


5196
2

C8-4FL4








pic


5197
2

C8-4FL5








pic


5198
2

C8-4FL6








pic


5199
2

C10-4FL1








pic


5200
2

C10-4FL2








pic


5201
2

C10-4FL3








pic


5202
2

C10-4FL4








pic


5203
2

C10-4FL5








pic


5204
2

C10-4FL6








pic


5205
2

C1-4FL1








dpm


5206
2

C1-4FL1








acac-3FL1


5207
2

C1-4FL1








acac-4FL1


5208
2

C1-4FL1








dpm


5209
2

C1-4FL1








dpm


5210
2


C1-4FL1





C6H13

acac


5211
2


C1-4FL1





CH3

acac


5212
2


C1-4FL1





CH3O

acac


5213
2


C1-4FL1





F

acac


5214
2


C1-4FL1





Cyclohexyl

acac


5215
2

F
C1-4FL1







acac


5216
2

CH3
C1-4FL1







acac


5217
2

OCH3
C1-4FL1







acac


5218
2


C1-4FL2





C6H13

acac


5219
2


C1-4FL2





CH3

acac


5220
2


C1-4FL2





CH3O

acac


5221
2


C1-4FL2





F

acac


5222
2


C1-4FL2





Cyclohexyl

acac


5223
2

F
C1-4FL2







acac


5224
2

CH3
C1-4FL2







acac


5225
2

OCH3
C1-4FL2







acac


5226
2








C1-4FL1


5227
3








C1-4FL2


5228
3








C1-4FL3


5229
3








C1-4FL4


5230
3








C1-4FL5


5231
3








C1-4FL6


5232
3








C2-4FL1


5233
3








C2-4FL2


5234
3








C2-4FL3


5235
3








C2-4FL4


5236
3








C2-4FL5


5237
3








C2-4FL6




























TABLE 13





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







6001
3

C1-5FL1











6002
3

C1-5FL2


6003
3

C1-5FL3


6004
3

C1-5FL4


6005
3

C1-5FL5


6006
3

C1-5FL6


6007
3

C2-5FL1


6008
3

C3-5FL1


6009
3

C4-5FL1


6010
3

C5-5FL1


6011
3

C6-5FL1


6012
3

C7-5FL1


6013
3

C8-5FL1


6014
3

C9-5FL1


6015
3

C10-5FL1


6016
3

C11-5FL1


6017
3


C1-5FL1


6018
3


C1-5FL2


6019
3


C1-5FL3


6020
3


C1-5FL4


6021
3


C1-5FL5


6022
3


C1-5FL6


6023
3


C2-5FL1


6024
3


C3-5FL1


6025
3


C4-5FL1


6026
3


C5-5FL1


6027
3


C6-5FL1


6028
3


C7-5FL1


6029
3


C8-5FL1


6030
3


C9-5FL1


6031
3


C10-5FL1


6032
3


C11-5FL1


6033
3







C1-5FL1


6034
3







C1-5FL2


6035
3







C1-5FL3


6036
3







C1-5FL4


6037
3







C1-5FL5


6038
3







C1-5FL6


6039
3







C2-5FL1


6040
3







C3-5FL1


6041
3







C4-5FL1


6042
3







C5-5FL1


6043
3







C6-5FL1


6044
3







C7-5FL1


6045
3







C8-5FL1


6046
3







C9-5FL1


6047
3







C10-5FL1


6048
3







C11-5FL1


6049
2


C1-5FL1







acac


6050
2


C1-5FL2







acac


6051
2


C1-5FL3







acac


6052
2


C1-5FL4







acac


6053
2


C1-5FL5







acac


6054
2


C1-5FL6







acac


6055
2


C2-5FL1







acac


6056
2


C3-5FL1







acac


6057
2


C4-5FL1







acac


6058
2


C5-5FL1







acac


6059
2


C6-5FL1







acac


6060
2


C7-5FL1







acac


6061
2


C8-5FL1







acac


6062
2


C9-5FL1







acac


6063
2


C10-5FL1







acac


6064
2


C11-5FL1







acac


6065
3

F
C1-5FL1


6066
3

CH3O
C1-5FL1


6067
3

F
C2-5FL1


6068
3

CH3O
C2-5FL1




























TABLE 14





Exemplified











Addition


Compound No.
n
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
ligand







7001
3

C1-6FL1











7002
3

C1-6FL2


7003
3

C1-6FL3


7004
3

C1-6FL4


7005
3

C1-6FL5


7006
3

C1-6FL6


7007
3

C2-6FL1


7008
3

C3-6FL1


7009
3

C4-6FL1


7010
3

C5-6FL1


7011
3

C6-6FL1


7012
3

C7-6FL1


7013
3

C8-6FL1


7014
3

C9-6FL1


7015
3

C10-6FL1


7016
3

C11-6FL1


7017
3


C1-6FL1


7018
3


C1-6FL2


7019
3


C1-6FL3


7020
3


C1-6FL4


7021
3


C1-6FL5


7022
3


C1-6FL6


7023
3


C2-6FL1


7024
3


C3-6FL1


7025
3


C4-6FL1


7026
3


C5-6FL1


7027
3


C6-6FL1


7028
3


C7-6FL1


7029
3


C8-6FL1


7030
3


C9-6FL1


7031
3


C10-6FL1


7032
3


C11-6FL1


7033
3







C1-6FL1


7034
3







C1-6FL2


7035
3







C1-6FL3


7036
3







C1-6FL4


7037
3







C1-6FL5


7038
3







C1-6FL6


7039
3







C2-6FL1


7040
3







C3-6FL1


7041
3







C4-6FL1


7042
3







C5-6FL1


7043
3







C6-6FL1


7044
3







C7-6FL1


7045
3







C8-6FL1


7046
3







C9-6FL1


7047
3







C10-6FL1


7048
3







C11-6FL1


7049
2


C1-6FL1







acac


7050
2


C1-6FL2







acac


7051
2


C1-6FL3







acac


7052
2


C1-6FL4







acac


7053
2


C1-6FL5







acac


7054
2


C1-6FL6







acac


7055
2


C2-6FL1







acac


7056
2


C3-6FL1







acac


7057
2


C4-6FL1







acac


7058
2


C5-6FL1







acac


7059
2


C6-6FL1







acac


7060
2


C7-6FL1







acac


7061
2


C8-6FL1







acac


7062
2


C9-6FL1







acac


7063
2


C10-6FL1







acac


7064
2


C11-6FL1







acac


7065
3

F
C1-6FL1


7066
3

CH3O
C1-6FL1


7067
3

F
C2-6FL1


7068
3

CH3O
C2-6FL1









The iridium coordination compound of the present invention is useful as a light emitting material for an organic EL device. Needless to say, the compound has high luminous efficiency. In addition, the compound is suitable for a spin coating process involving applying a solution of the compound, various printing methods, and an application mode involving the use of an ink-jet nozzle.
Next, a light emitting device of the present invention will be described.
A light emitting device includes at least two electrodes, and a light emitting layer interposed between the electrodes, in which the light emitting layer contains the light emitting material according to the present invention.
The light emitting layer may be a layer formed only of the light emitting material of the present invention, or may be a layer formed of the light emitting material of the present invention and a host compound. In the case of a layer formed of the light emitting material and the host compound, the content of the light emitting material of the present invention is not particularly limited; the content is preferably 0.1 wt % or more to 99 wt % or less, or more preferably 1 wt % or more to 70 wt % or less.
Examples of the host compound include an oligofluorene represented by the following structural formula (8) and a polyfluorene having a molecular weight of 10,000 or more to 100,000 or less represented by the following structural formula (9).




n represents 1 or more to 20 or less.
R61 and R62 are each independently selectable from functional groups in each fluorene group, and each represent a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.




R41 and R42 are each independently selectable from functional groups in each fluorene group, and are each selected from a linear, branched, or cyclic alkyl group having 2 or more carbon atoms, and a trifluoromethyl group.
An oligofluorene or polyfluorene having a structure in which fluorene groups are continuously bonded to each other has the following properties.
(1) A charge transporting ability upon application of an electric field to the light emitting layer is high.
(2) The lowest triplet excitation energy (T1) level of the oligofluorene or polyfluorene is higher than the T1 level of the iridium coordination compound of the present invention, so excitation energy can be efficiently transferred to the iridium coordination compound of the present invention.
(3) The T1 level of the oligofluorene or polyfluorene is higher than the T1 level of the iridium coordination compound of the present invention, so the oligofluorene or polyfluorene does not absorb the excitation energy of the iridium coordination compound, and the iridium coordination compound can emit light with high efficiency.
(4) Compatibility between the iridium coordination compound of the present invention and the oligofluorene or polyfluorene is good, so a high-quality thin film of the materials can be formed upon production of the device.
Hereinafter, examples will be described.
EXAMPLES 1 TO 6
Hereinafter, a method of synthesizing each of Exemplified Compound 1001 (Example 1), Exemplified Compound 1002 (Example 2), Exemplified Compound 1003 (Example 3), Exemplified Compound 1004 (Example 4), Exemplified Compound 1007 (Example 5), and Exemplified Compound 1008 (Example 6) will be described.
The synthesis of each of those compounds follows a general synthesis method involving producing a C—C bond or C—N bond between aryl groups, and employs mainly a Suzuki coupling method based on a reaction between a halide and boric acid using a palladium catalyst.
First, the following scheme shows a method of synthesizing the intermediate of an oligofluorenyl group involving sequentially coupling fluorene groups by Suzuki coupling.




The following schemes each show a scheme in which a phenylisoquinoline skeleton and an oligofluorenyl group are bonded to each other. The ligands of Exemplified Compounds 1001 and 1004 can be synthesized by the schemes. 1H-NMR is employed for the identification of a compound.




Similarly, the following schemes each show the synthesis of: the ligand of Exemplified Compound 1002; the ligand of Exemplified Compound 1003; the ligand of Exemplified Compound 1007; or the ligand of Exemplified Compound 1008. 1H-NMR is employed for the identification of each compound.






















The following scheme is a synthesis scheme for coordinating each of the ligands synthesized in the above schemes to iridium. In each of all exemplified compounds, iridium can be turned into a coordination compound by common steps. Each of an Ir(acac) body to be produced in a second step and Ir with three ligands to be produced in a third step can be used as a light emitting material; in each of these examples, Ir with three ligands to be produced in the third step is a target compound.




EXAMPLES 7 TO 9
These examples are synthesis examples of Exemplified Compound 1014 (Example 7), Exemplified Compound 1015 (Example 8), and Exemplified Compound 1016 (Example 9).
Procedures for synthesizing ligands were shown below. In each procedure, a ligand was synthesized by using a Suzuki coupling reaction, in which a palladium catalyst was used, plural times.







Iridium complexes were synthesized by using the ligands in accordance with procedures similar to those of Examples 1 to 6.
The compounds were identified by employing proton NMR and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MARDI-TOF-MASS) (Autoflex type manufactured by Bruker Daltonics Inc. (Germany)).
FIGS. 1A to 1C showed the emission spectra of solutions of Exemplified Compounds 1014 to 1016 in toluene. Exemplified Compounds 1014, 1015, and 1016 had light emission peak wavelengths of 620 nm, 633 nm, and 633 nm, respectively, and each emitted pure red light.
EXAMPLES 10 TO 12
Examples of organic LED devices each using Exemplified Compound 1014, 1015, or 1016 will be described. Each of those complexes can be dissolved well in a xylene solution, and is suitable for an organic EL device to be produced by a spin coating method.
A device having a constitution including three organic layers was produced. ITO having a thickness of 100 nm was patterned into a circular shape on a glass substrate so that an electrode area would be 3.14 mm2.
PEDOT (for an organic EL) manufactured by Bayer was applied onto the ITO substrate by spin coating at 1,000 rpm (20 seconds) so as to form a film having a thickness of 40 nm. The resultant was dried in a vacuum chamber at 120° C. for 1 hour.
The upper portion of the resultant was coated with the following solution by spin coating under a nitrogen atmosphere at 2,000 rpm for 20 seconds, whereby an organic film having a thickness of 60 nm (light emitting layer) was formed. After the formation of the film, the resultant was dried under conditions identical to those at the time of the formation of the PEDOT film.
Xylene: 10 g/polyfluorene shown below (molecular weight 100,000): 70 mg/exemplified compound: 30 mg




The substrate was mounted in a vacuum vapor deposition chamber, and Bphen shown below was deposited from the vapor in a vacuum to form a film having a thickness of 40 nm.




The total thickness of the organic layers is 140 nm.
Next, a cathode having the following constitution was formed.
Metal electrode layer (10 nm): AlLi alloy (Li content 1.8 mass %)/metal electrode layer (100 nm): Al
After the completion of the above film formation, the resultant device is taken out and evaluated.
Each device is evaluated for characteristics by applying a DC voltage while the cathode is defined as a negative electrode and ITO is defined as a positive electrode. The voltage-current characteristics of each device showed good rectifying property. The emission spectrum and emission luminance of each device were measured with spectrum measuring machines SR1 and BM7 manufactured by TOPCON CORPORATION. A current value at the time of the application of a voltage can be measured with a 4140Bd manufactured by Hewlett-Packard Company. Three devices in these examples each emitted good red light. The following table shows the EL luminous efficiency and current density of each device. EL light emission was good at 200 cd/m2, and maintained its quality even after energization for 10 hours.











TABLE 15








Luminous
Current density



Light emitting
efficiency
(at the time of



material
(at 200 cd/m2)
application of 5 V)



















Example 10
Exemplified
4.5 cd/A
15 mA/cm2



Compound 1014


Example 11
Exemplified
2.3 cd/A
10 mA/cm2



Compound 1015


Example 12
Exemplified
6.0 cd/A
28 mA/cm2



Compound 1016









The results of these examples showed that the compound of the present invention was effective for an organic EL device. In addition, the concentration of a light emitting material in a light emitting layer is typically about 1% or more to 10% or less in order that the concentration quenching of the light emitting material may be avoided; high luminous efficiency was attained even at a light emitting material concentration of 30% as in these examples. In addition, a problem such as phase separation from the host of a light emitting layer was not observed, and stable light emission was obtained.
EXAMPLES 13 AND 14
In each of these examples, only an exemplified compound is used in a light emitting layer.
Devices were each produced in the same manner as in each of Examples 7 to 9 except that a light emitting layer was produced by using the following solution.
Chlorobenzene: 10 g/exemplified compound: 90 mg
The efficiency and current value of a completed device are as shown in the following table.











TABLE 16








Luminous




Light emitting
efficiency



material
(at 200 cd/m2)
Current density



















Example 13
Exemplified
2.1 cd/A
28 mA/cm2



Compound 1014


Example 14
Exemplified
2.3 cd/A
40 mA/cm2



Compound 1016









Even when a light emitting layer was formed only of the iridium coordination compound of the present invention, that is, the content of the compound in the layer was 100%, the iridium coordination compound of the present invention functioned as a light emitting center in an EL device, and was able to provide stable, good luminous efficiency.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2006-187811, filed Jul. 7, 2006, which is hereby incorporated by reference herein in its entirety.

## Claims

1. A light emitting material represented by the following structural formula:

2. A light emitting device comprising:
two electrodes; and
a light emitting layer interposed between the electrodes,
wherein the light emitting layer contains the light emitting material according to claim 1.

3. The light emitting device according to claim 2, wherein the light emitting layer contains, as a host compound, an oligofluorene represented by the following structural formula (8):




wherein:
n represents 1 to 20; and
R61 and R62 are each independently selected from functional groups in each fluorene group, and each represent a trifluoromethyl group, or a linear, branched, or cyclic alkyl or alkoxyl group having 2 or more carbon atoms a hydrogen atom of which may be substituted by a halogen atom.

4. The light emitting device according to claim 2, wherein the light emitting layer contains, as a host compound, a polyfluorene having a molecular weight of 10,000 to 100,000 represented by the following structural formula (9):




wherein R61 and R62 are each independently selected from functional groups in each fluorene group, and are each selected from a linear, branched, or cyclic alkyl group having 2 or more carbon atoms, or a trifluoromethyl group.

5. The light emitting device according to claim 2, wherein the light emitting layer comprises a part formed only of the light emitting material.