JP2003342284A - Metal coordination compound, light-generating element and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a new light-generating material, and to provide a light- generating element and a display device each having a high efficiency light generation, keeping a high brightness for a long time and capable of generating a long wave length light by using the same. <P>SOLUTION: A metal coordination compound is expressed by the formula (1): ML<SB>m</SB>L'<SB>n</SB>(wherein, M is Ir or Pt metal atom; L, L' are different bidentate ligands; (m) is 1, 2 or 3; (n) is 0, 1 or 2, provided that (m+n) is 2 or 3; the partial structure ML<SB>m</SB>is expressed by formula (2); and the partial structure ML'<SB>n</SB>is expressed by formula (3) or (4) [wherein, X, X' are each a cyclic group which may have a substituent bonded to the metal atom M through N; Y is a cyclic group which may have a substituent bonded to the metal atom M through C; Z is a cyclic group which may have a substituent; A is an alkyl, N, or the like; E is a single bond, an alkylene, or the like; and G, G' and J are each H, an alkyl, or the like]. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal coordination compound,
It also relates to a light emitting device using the metal coordination compound, and more specifically to an organic electroluminescence device (organic EL device) using the metal coordination compound as a light emitting material.

[0002]

2. Description of the Related Art Organic EL devices have been vigorously studied for application as light-emitting devices with high-speed response and high efficiency. The basic structure thereof is shown in FIGS. 1 (a) and 1 (b) [eg Macromol. Symp. 125, 1-48 (19
97)].

As shown in FIG. 1, an organic EL element is generally composed of a plurality of organic film layers on a transparent substrate 15 between a transparent electrode 14 and a metal electrode 11.

In FIG. 1A, the organic layer comprises a light emitting layer 12 and a hole transport layer 13. ITO or the like having a large work function is used as the transparent electrode 14, and has good hole injection characteristics from the transparent electrode 14 to the hole transport layer 13. As the metal electrode 11, a metal material having a small work function, such as aluminum, magnesium, or an alloy using them, is used to have good electron injecting property to the organic layer. A film thickness of 50 to 200 nm is used for these electrodes.

For the light emitting layer 12, an aluminum quinolinol complex having an electron transporting property and a light emitting property (a typical example is Alq3 shown in Chemical formula 3) is used. In addition, the hole transport layer 13
For example, a material having an electron donating property such as a biphenyldiamine derivative (a typical example is α-NPD shown in Chemical formula 3) is used.

The element having the above-described structure exhibits rectifying properties, and when an electric field is applied so that the metal electrode 11 serves as a cathode and the transparent electrode 14 serves as an anode, electrons are injected from the metal electrode 11 into the light emitting layer 12, and the transparent electrode 15 is formed. Holes are injected from.

The injected holes and electrons recombine in the light emitting layer 12 to generate excitons and emit light. At this time, the hole transport layer 13 plays a role of an electron blocking layer, the recombination efficiency of the interface of the light emitting layer 12 / the hole transport layer 13 is increased, and the light emitting efficiency is increased.

Further, in FIG. 1B, an electron transport layer 16 is provided between the metal electrode 11 and the light emitting layer 12 of FIG. 1A. Efficient light emission can be achieved by separating light emission from electron / hole transport to form a more effective carrier blocking structure. As the electron transport layer 16, for example, an oxadiazole derivative or the like can be used.

Up to now, in the light emission generally used in the organic EL device, the fluorescence at the time of reaching the ground state is extracted from the singlet excitons of the molecule at the emission center. On the other hand, devices that utilize phosphorescence emission via triplet excitons, rather than fluorescence emission via singlet excitons, have been studied. A representative document that has been published is Document 1: Improved energy transfer.
r in electrophosphorescence
t device (DFO'Brien et al., App
Lied Physics Letters Vol
74, No3 p422 (1999)), Reference 2: Ve
ry high-efficiency green o
organic light-emitting dev
icesbasd on electrophosph
orence (MA Baldo et al., Appl.
ied Physics Letters Vol 7
5, No1 p4 (1999)).

In these documents, a four-layer structure of the organic layer shown in FIG. 1 (c) is mainly used. It is a hole transport layer 13, a light emitting layer 12, an exciton diffusion prevention layer 1 from the anode side.
7 and the electron transport layer 16. The materials used are
They are the carrier transport material and the phosphorescent material shown in Chemical formula 3. Abbreviations of each material are as follows. Alq3: Aluminum-quinolinol complex α-NPD: N4, N4′-Di-naphthalle
n-1-yl-N4, N4′-diphenyl-bi
phenyl-4,4'-diamine CBP: 4,4'-N, N'-dicarbazole
-Biphenyl BCP: 2,9-dimethyl-4,7-diph
enyl-1,10-phenanthroline Ir (ppy) ₃ : iridium-phenylpyridine complex

[0011]

[Chemical 3]

High efficiency was obtained in Documents 1 and 2 because α-NPD was formed in the hole transport layer 13 and Alq was formed in the electron transport layer 16.
3, BCP in the exciton diffusion prevention layer 17 and CB in the light emitting layer 12
P is a host material, and PtOEP or Ir (ppy) ₃ which is a phosphorescent material is mixed at a concentration of about 6%.

The reason why phosphorescent light-emitting materials are particularly attracting attention is that, in principle, high luminous efficiency can be expected. The reason is that the number of excitons generated by carrier recombination is 1
It consists of singlet excitons and triplet excitons, and the probability is 1: 3.
Is. Up to now, the organic EL device has taken out fluorescence emitted from the transition from singlet excitons to the ground state, but in principle, the emission yield is 25% with respect to the number of excitons generated. And this was the theoretical upper limit. However, if phosphorescence from excitons generated from the triplet is used, at least a triple yield is expected in principle, and further, the interlet crossing from the singlet to the triplet, which is energetically high, is expected. If we consider the transfer due to
An emission yield of 0% can be expected.

In addition, for documents requiring triplet light emission, JP-A No. 11-329739 (organic EL device and manufacturing method thereof) and JP-A No. 11-256148 (light emitting material and the same are used). Organic EL elements), Japanese Patent Laid-Open No. 8-319482 (organic electroluminescent element) and the like.

[0015]

In the above-mentioned organic EL device using phosphorescence, the luminous efficiency and the device stability are problems. The cause of the emission deterioration of the phosphorescent device is not clear, but since the triplet lifetime is generally longer than the singlet lifetime by three digits or more, the molecule is left in a high-energy state for a long time, so It is thought that reactions, formation of excited multimers, changes in molecular fine structure, and changes in the structure of surrounding substances may occur.

As an emission center material used for a phosphorescent device, a compound having high efficiency and high stability is desired.

Therefore, an object of the present invention is to provide a novel light emitting material, and thereby to provide a light emitting device and a display device capable of emitting light with high efficiency, maintaining high brightness for a long period of time, and extending the wavelength. .

[0018]

That is, the metal coordination compound of the present invention is characterized by being represented by the following general formula (1). ML _m L ′ _n (1) [In the formula, M is a metal atom of Ir or Pt, and L and L ′ represent different bidentate ligands. m is 1 or 2
Or 3 and n is 0 or 1 or 2. However, m + n is 2 or 3. The partial structure ML _m is represented by the following general formula (2), and the partial structure ML ′ _n is represented by the following general formula (3) or (4).

[0019]

[Chemical 4]

N and C are nitrogen and carbon atoms.

X and X'are metal atoms M via a nitrogen atom.
A cyclic group which may have a substituent bonded to Y,
Is a cyclic group which may have a substituent bonded to the metal atom M via a carbon atom, and Z is a cyclic group which may have a substituent. The substituents of these cyclic groups are a halogen atom, a cyano group, a nitro group, a di-substituted amino group (the substituents each independently may have a phenyl group, a naphthyl group (the substituent is a halogen atom , A methyl group, a trifluoromethyl group, or a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom.)
Alternatively, it is a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. }, A linear or branched alkyl group having 1 to 20 carbon atoms {1 in the alkyl group
Two or more non-adjacent methylene groups are -O-,
-S-, -CO-, -CO-O-, -O-CO-, -C
H = CH-, -C≡C- may be substituted,
One or two or more methylene groups in the alkyl group may have a divalent aromatic ring group which may have a substituent (the substituent is a halogen atom, a cyano group, a nitro group, a carbon number of 1 to 20). A linear or branched alkyl group (wherein one or two or more non-adjacent methylene groups in the alkyl group are-
O-, -S-, -CO-, -CO-O-, -O-CO
-, -CH = CH-, -C≡C- may be substituted, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. ) Is shown. ), The hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, adjacent substituents may be bonded to each other to form a ring structure.

X and Y, and X and Z are bonded by a covalent bond via an A atom or an A atomic group.

A is CR, N, B, SiR ',
R and R ′ each represent a hydrogen atom or an aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched group having 1 to 8 carbon atoms). An alkyl group, in which a hydrogen atom in the alkyl group may be substituted with a fluorine atom), or a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups Alternatively, two or more methylene groups which are not adjacent to each other are -O-, -S-, -CO-, -CO-O.
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. A good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups or a non-adjacent group
One or more methylene groups are -O-, -S-, -CO-, -C
O-O-, -O-CO-, -CH = CH-, -C≡C-
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. ) Is shown. )
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. } Is selected.

Y and Z are bonded by a covalent bond through an E atom or an E atomic group.

E is a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms (one methylene group in the alkylene group is --O--, --S--, --CO--, --CO).
It may be replaced by -O-, -O-CO-, -CH = CH-, -C≡C-, and the hydrogen atom in the alkylene group may be replaced by a fluorine atom. ).

G, G'and J are each independently a linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are -O). -, -S-, -CO-, -CO-O
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. Good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a trialkylsilyl group (the alkyl groups are each independently a linear or branched alkyl group having 1 to 8 carbon atoms) And a linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are -O-, -S-,
-CO-, -CO-O-, -O-CO-, -CH = CH
-, -C≡C- may be substituted, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. ) Is shown. Further, adjacent substituents may be bonded to each other to form a ring structure. ), The hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, A di-substituted amino group {the substituents each independently may have a phenyl group, a naphthyl group (the substituents are a halogen atom, a methyl group or a trifluoromethyl group) or carbon. It is a linear or branched alkyl group having 1 to 8 atoms, and a hydrogen atom in the alkyl group may be substituted with a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, J may be a hydrogen atom. ]

In the metal coordination compound of the present invention, n in the general formula (1) is 0, and the partial structure ML ′ _n in the general formula (1) is represented by the general formula (3). In the general formula (1), the partial structure ML ′ _n is preferably represented by the general formula (4).

In the general formula (1), the
Partial structure ML represented by general formula (2) _mIs the following general formula
It is preferably selected from (5) to (9).

[0029]

[Chemical 5]

[The cyclic group may have a substituent, and these substituents include a halogen atom, a cyano group, a nitro group and a disubstituted amino group (the substituents each independently have a substituent. Phenyl group and naphthyl group (wherein the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group is It may be substituted with a fluorine atom) or a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. }, A linear or branched alkyl group having 1 to 20 carbon atoms {one or two or more non-adjacent methylene groups in the alkyl group are -O-, -S-, -CO-, -CO. -O
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. A good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups or a non-adjacent group
One or more methylene groups are -O-, -S-, -CO-, -C
O-O-, -O-CO-, -CH = CH-, -C≡C-
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. ) Is shown. )
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, adjacent substituents may be bonded to each other to form a ring structure. ]

The light emitting device of the present invention is characterized by having an organic compound layer containing the metal coordination compound, wherein the organic compound layer containing the metal coordination compound is sandwiched between two electrodes facing each other. The electroluminescent element that emits light by applying a voltage between the electrodes is preferable.

Further, the display device of the present invention is characterized in that the light emitting element has a display element and a portion for driving the light emitting element.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION When the light emitting layer comprises a host material having a carrier transporting property and a phosphorescent guest, the main processes leading to phosphorescence emission from triplet excitons are as follows. Consists of processes. 1. Transport of electrons and holes in the light emitting layer 2. Host exciton generation 3. Excitation energy transfer between host molecules 4. 4. Transfer of excitation energy from host to guest Guest triplet exciton generation 6. Guest triplet exciton → phosphorescence in the ground state

Desired energy transfer and light emission in each process occur in competition with various deactivation processes.

It goes without saying that the emission quantum yield of the emission center material itself is large in order to increase the emission efficiency of the EL element. However, how efficiently the energy transfer between the host and the host or between the host and the guest can be a big problem. Further, although the cause of the luminescence deterioration due to energization is not clear so far, it is assumed that it is related to at least the luminescence center material itself or the environmental change of the luminescence material due to its peripheral molecules.

Therefore, the inventors of the present invention conducted various studies and found that an organic electroluminescent device using the metal coordination compound represented by the general formula (1) as a luminescent center material emits light with high efficiency and keeps light for a long period of time. It was found that the brightness was maintained and the deterioration due to energization was small.

In the metal coordination compound represented by the general formula (1), when n is 0, the partial structure ML ′ _n is represented by the general formula (3), or the partial structure ML ′.
_{The case} where _n is represented by the general formula (4) is preferable. The partial structure ML _m represented by the general formula (2) is preferably selected from the general formulas (5) to (9).

The metal coordination compound used in the present invention emits phosphorescent light, and the lowest excited state is a triplet state MLCT * (Metal-to-Ligand channel).
charge transfer) excited state or π-π
* It is considered to be in an excited state. Phosphorescence is generated at the transition from these states to the ground state.

The phosphorescent yield of the luminescent material of the present invention is 0.0
A high value of 1 or more is obtained, and the phosphorescence lifetime is 0.1 to 100.
It had a short life of μsec. The short phosphorescence lifetime means
It becomes a condition for high luminous efficiency when it is used as an EL element. That is, if the phosphorescence lifetime is long, there are many molecules in the triplet excited state in the light emission waiting state, and there is a problem that the light emission efficiency is reduced particularly at a high current density. The material of the present invention has a high phosphorescence emission yield and is suitable as a light emitting material for an EL device having a short phosphorescence lifetime. In fact, even in the electric current test, the use of the light emitting material of the present invention showed high stability.

The light emitting device of the present invention has an organic compound layer containing a metal coordination compound represented by the general formula (1), and as shown in FIG. 1, the layers containing the metal coordination compound face each other. It is preferable that the electroluminescent element is sandwiched between two electrodes and emits light by applying a voltage between the electrodes.

The highly efficient light emitting device shown in the present invention can be applied to products requiring energy saving and high brightness. Examples of applications include display devices, lighting devices, and light sources for printers.
A backlight of a liquid crystal display device is considered. As a display device, energy saving, high visibility and lightweight flat panel display can be realized. Further, as the light source of the printer, the laser light source portion of the laser beam printer which is widely used at present can be replaced with the light emitting element of the present invention. An image is formed by arranging independently addressable elements on the array and exposing the photosensitive drum to a desired exposure. By using the element of the present invention, the device volume can be significantly reduced. Regarding the lighting device and the backlight, the energy saving effect of the present invention can be expected.

For application to a display, a method of driving using a TFT drive circuit which is an active matrix method can be considered.

An example using an active matrix substrate in the device of the present invention will be described below with reference to FIGS.

FIG. 4 schematically shows an example of the structure of a panel provided with EL elements and driving means. A scan signal driver, an information signal driver, and a current supply source are arranged on the panel.
It is connected to the current supply line. The pixel circuit shown in FIG. 5 is arranged at the intersection of the gate selection line and the information signal line. The scan signal driver includes gate selection lines G1, G2, G3. ． ． Gn
Are sequentially selected, and the image signal is applied from the information signal driver in synchronization with this.

Next, the operation of the pixel circuit will be described. In this pixel circuit, when a selection signal is applied to the gate selection line, the TFT1 is turned on, the image signal is supplied to Cadd, and the gate potential of the TFT2 is determined. A current is supplied to the EL element from the current supply line according to the gate potential of the TFT 2. The gate potential of TFT2 is TFT
Since 1 is held in Cadd until the next scan is selected, the EL element continues to flow until the next scan is performed. As a result, it becomes possible to always emit light for one frame period.

FIG. 6 is a schematic view showing an example of a sectional structure of the TFT substrate used in the present invention. A p-Si layer is provided on the glass substrate, and the channel, drain, and source regions are each doped with necessary impurities. A gate electrode is provided on this via a gate insulating film, and
A drain electrode and a source electrode connected to the drain region and the source region are formed. An insulating layer and an ITO electrode as a pixel electrode are laminated on these, and the ITO and drain electrodes are connected by a contact hole.

The present invention is not particularly limited to the switching element, and can be easily applied to a single crystal silicon substrate, an MIM element, an a-Si type or the like.

An organic EL display panel can be obtained by sequentially laminating a multi-layer or single-layer organic EL layer / cathode layer on the ITO electrode. By driving the display panel using the light emitting material of the present invention for the light emitting layer, it is possible to achieve a stable display for a long period of time with good image quality.

Specific structural formulas of the metal coordination compounds used in the present invention are shown in Tables 1 to 7 below. However, these are merely representative examples, and the present invention is not limited thereto. The abbreviations used in Tables 1 to 7 represent the structures shown below.

[0050]

[Chemical 6]

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

[Table 5]

[0056]

[Table 6]

[0057]

[Table 7]

[0058]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

Example 1 Synthesis of Exemplified Compound 113 Synthesis of 2- (9H-carbazol-9-yl) -pyridine 18.8 g (111 mmo) of carbazole was placed in a reaction vessel.
l), 2-iodopyridine 25 g (122 mmol),
23 g (167 mmol) of potassium carbonate, 7 g of copper powder (1
11 mmol), o-dichlorobenzene (ODC) 50
ml was charged and the mixture was stirred at 180 ° C. for 24 hours. The reaction product was cooled to room temperature, 100 ml of toluene was injected, and the precipitate was collected by filtration. The filtrate was concentrated and then purified by silica gel column chromatography using chloroform as an eluent.
Recrystallize with hexane-ethanol solution to give 2- (9H
-Carbazol-9-yl) -pyridine 9.8 g (40
mmol, yield 36%).

Tetrakis [2- (9H-carbazol-9-yl) -pyridine-C ¹ , N] (μ-dichloro)
Synthesis of diiridium (III) In a 200 ml three-necked flask, iridium chloride (II
I) .3 hydrate 0.58 g (1.64 mmol), 2-
(9H-carbazol-9-yl) -pyridine 1.01
g (4 mmol), ethoxyethanol 45 ml and water 1
5 ml was added, and the mixture was stirred under a nitrogen stream at room temperature for 30 minutes and then refluxed for 24 hours. The reaction product was cooled to room temperature, and the precipitate was collected by filtration, washed with water, and then washed successively with ethanol and acetone. After drying under reduced pressure at room temperature, tetrakis [2- (9H-
Carbazol-9-yl) -pyridine-C ¹ , N] (μ
-Dichloro) diiridium (III) powder 1.05 g
(Yield 90%) was obtained.

Bis [2- (9H-carbazole-9-
Yl) -Pyridine-C ¹ , N] (acetylacetonato)
Synthesis of Iridium (III) (Exemplified Compound 113) Ethoxyethanol 70 was added to a 200 ml three-necked flask.
ml, tetrakis [2- (9H-carbazol-9-yl) -pyridine-C ¹ , N] (μ-dichloro) diiridium (III) 1.03 g (0.72 mmol), acetylacetone 0.22 g (2.10 mmol) ) And 1.04 g (9.91 mmol) of sodium carbonate were added, and the mixture was stirred under a nitrogen stream at room temperature for 1 hour and then refluxed for 15 hours. The reaction product was ice-cooled, and the precipitate was collected by filtration and washed with water. The precipitate was purified by silica gel column chromatography (eluent: chloroform / methanol: 30/1), and bis [2- (9H
-Carbazol-9-yl) -pyridine-C ¹ , N]
0.70 g (yield 62%) of powder of (acetylacetonato) iridium (III) (exemplary compound No. 113) was obtained. M of this compound by MALDI-TOF MS
It was confirmed ⁺ of 778.2.

Example 2 Synthesis of Exemplified Compound 1 In a 100 ml three-necked flask, 0.31 g (1.25 mmol) of 2- (9H-carbazol-9-yl) -pyridine synthesized in the same manner as in Example 1. ), And bis [2- (9H-carbazole-9-synthesized in the same manner as in Example 1.
Yl) -Pyridine-C ¹ , N] (acetylacetonato)
Iridium (III) 0.399 g (0.5 mmol)
And 25 ml of glycerol were added, and the mixture was heated and stirred at about 180 ° C. for 8 hours under a nitrogen stream. The reaction product was cooled to room temperature, poured into 150 ml of water, and the precipitate was collected by filtration and washed with water, and then at 100 ° C.
And dried under reduced pressure for 5 hours. This precipitate was purified by silica gel column chromatography using chloroform as an eluent, and tris [2- (9H-carbazol-9-yl) -pyridine-
C ¹ , N] iridium (III) (exemplified compound No.
0.20 g (yield 44%) of the powder of 1) was obtained. MALD
92 by I-TOF MS which is the M ⁺ of this compound.
2.2 was confirmed.

Example 3 Synthesis of Exemplified Compound 140 2- (9-methyl-9H-fluoren-9-yl)-
A reaction vessel for synthesizing pyridine was charged with 13.6 g (82 mmol) of fluorene and 200 ml of dry tetrahydrofuran (THF),
It cooled at -60 degreeC under nitrogen stream. 1.6 M n-butyllithium (nBuLi) 51.2 ml (82 mmo
l) was slowly added dropwise, and then the mixture was stirred at 0 ° C. for 1 hour. After cooling to −60 ° C. again, 20 ml of dry THF containing 16.8 g (82 mmol) of 2-iodopyridine.
After slowly adding the solution dropwise, the mixture was stirred at 10 ° C. for 1 hour. After cooling to −60 ° C. again, n of 1.6M
After slowly adding 51.2 ml (82 mmol) of BuLi, the mixture was stirred at 0 ° C. for 1 hour. Again, -60 ℃
After cooling to 11.6 g (8
A solution of 2 mmol) in 20 ml of dry THF was slowly added dropwise, followed by stirring at 10 ° C. for 2 hours. The reaction solution was poured into ice water and extracted with toluene. The organic layer was washed with water and dried over magnesium sulfate. The organic layer was concentrated and then purified by silica gel column chromatography using toluene / THF (10/1) as an eluent. Recrystallization was performed with an ethanol solution, and 6.5 g (25 mmol, 2- (9-methyl-9H-fluoren-9-yl) -pyridine
Yield 31%) was obtained.

Bis [2- (9-methyl-9H-fluoren-9-yl) -pyridine-C ¹ , N] (acetylacetonato) iridium (III) (Exemplary compound 140)
Synthesis of 2- (9H-carbazol-9-yl) -pyridine was replaced by 2- (9-methyl-9H-fluoren-9-yl) -pyridine in the same manner as in Example 1 except that bis [ 2- (9-methyl-9H-fluorene-9
- yl) - pyridine -C ^1, N] (to synthesize acetyl acetonate) iridium (III) (exemplified compound 140). M of this compound by MALDI-TOF MS
It was confirmed ⁺ of 776.2.

Example 4 Synthesis of Exemplified Compound 34 Instead of 2- (9H-carbazol-9-yl) -pyridine, 2- (9-methyl-9H-fluoren-9-yl) -pyridine was added to bis [ 2- (9H-carbazole-
9-yl) -pyridin-C ¹ , N] (acetylacetonato) iridium (III) instead of bis [2- (9-
Methyl-9H-fluoren-9-yl) -pyridine-C
¹ , N] (Acetylacetonato) iridium (III)
Tris 2- (9-
Methyl-9H-fluoren-9-yl) -pyridine-C
¹ , N] iridium (III) (exemplary compound 34) was synthesized. 961.3 which is M ⁺ of this compound was confirmed by MALDI-TOF MS.

<Examples 5 to 8> In this example, as the element structure, the element having four organic layers shown in FIG. 1C was used. 100 nm IT on a glass substrate (transparent substrate 15)
The O (transparent electrode 14) was patterned. On the ITO substrate, the following organic layers and electrode layers were vacuum-deposited by resistance heating in a vacuum chamber of 10 ⁻⁴ Pa to continuously form a film so that the opposing electrode area was 3 mm ² . Organic layer 1 (hole transport layer 13) (40 nm): α-NP
D Organic layer 2 (light emitting layer 12) (30 nm): CBP: predetermined metal coordination compound (weight ratio 8 wt%) Organic layer 3 (exciton diffusion prevention layer 17) (10 nm) BCP organic layer 4 (electron transport layer) 16) (30 nm): Alq3 Metal electrode layer 1 (15 nm): AlLi alloy (Li content 1.8 wt%) Metal electrode layer 2 (100 nm): Al

As the coordination compound, no. 1, No. Three
4, No. 113 and No. 113. 140 compounds were used.

The characteristics of the EL element were measured by measuring the current-voltage characteristics with a micro ammeter 4140B manufactured by Hewlett-Packard Company, and the emission brightness was measured with BM7 manufactured by Topcon Corporation. The devices corresponding to the respective coordination compounds of this example showed good rectifying properties.

When a voltage of 12 V was applied, light emission from this EL device was confirmed. Each of the emitted light was the element of Example 5 (Compound No. 1): 1000 cd / m
² Element of Example 6 (Compound No. 34): 950 cd / m
² Element of Example 7 (Compound No. 113): 900 cd /
m ² Device of Example 8 (Compound No. 140): 900 cd /
It was m ² .

In order to know the emission characteristics of these coordination compounds, the emission spectrum of the solution was measured. Using a spectrofluorometer (F4500 manufactured by Hitachi), excitation light of about 350 nm was applied to the toluene solution of the coordination compound to measure the emission spectrum. Emission spectrum is EL when voltage is applied
It was confirmed that the emission of the EL device was the emission from the coordination compound in agreement with the spectrum value of the device.

When a voltage was applied to these elements, stable and highly efficient light emission was obtained, and stable light emission was obtained even after energizing for 100 hours continuously.

Example 9 The simple matrix type organic EL device shown in FIG. 2 was prepared by the following procedure.

Length 75 mm, width 75 mm, thickness 1.1 mm
An ITO film having a thickness of about 100 nm was formed as a transparent electrode 22 (anode side) on the glass substrate 21 of No. 1 by a sputtering method, and LINE / SPACE = 100 μ was used as a simple matrix electrode.
100 lines were patterned at an interval of m / 40 μm. Next, using the same organic material as in Example 5, an organic compound layer 23 consisting of four layers was formed under the same conditions.

Then, LINE / SP is formed by mask vapor deposition.
ACE = 100 μm / 40 μm, the vacuum degree is 2.7 × 10 so that the metal electrode of 50 lines is orthogonal to the ITO electrode 22.
^A film was formed by vacuum evaporation under the condition of ^-3 Pa (2 x 10 ^-5 Torr). The metal electrode (cathode 24) is made of an Al-Li alloy (Li: 1.3 wt%) with a film thickness of 10 nm, followed by Al.
-Al was formed to a thickness of 150 nm on the Li layer.

In the glove box filled with the nitrogen atmosphere, the 100 × 100 simple matrix type organic EL device is operated in the range of 6V to 14V by the scanning signal of 10V and the information signal of ± 4V as shown in FIG. Matrix drive was performed. When interlaced driving was performed at a frame frequency of 30 Hz, a smooth moving image was confirmed.

[0076]

As described above, the light emitting device of the present invention using the metal coordination compound represented by the general formula (1) as the luminescent center material exhibits not only high efficiency emission but also high brightness for a long period. An excellent element to keep. The light emitting device of the present invention is also excellent as a display device.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a light emitting device of the present invention.

FIG. 2 is a diagram showing a simple matrix type organic EL device of Example 9.

FIG. 3 is a diagram showing a drive signal according to a ninth embodiment.

FIG. 4 is a diagram schematically illustrating an example of a configuration of a panel including an EL element and a driving unit.

FIG. 5 is a diagram showing an example of a pixel circuit.

FIG. 6 is a schematic diagram showing an example of a cross-sectional structure of a TFT substrate.

[Explanation of symbols]

11 metal electrodes 12 Light-emitting layer 13 Hall transport layer 14 Transparent electrode 15 Transparent substrate 16 Electron transport layer 17 Exciton diffusion prevention layer 21 glass substrate 22 ITO electrode (transparent electrode) 23 Organic compound layer 24 cathode

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Kamagai             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Shinjiro Okada             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Akira Tsuboyama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Seiji Miura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Takashi Moriyama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hironobu Iwawaki             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 3K007 AB02 AB03 DB03                 4H050 AA01 AA03 AB91 WB11 WB13                       WB21

Claims (8)

[Claims] 1. A metal coordination compound represented by the following general formula (1): ML _m L ′ _n (1) [In the formula, M is a metal atom of Ir or Pt, and L and L ′ represent different bidentate ligands. m is 1 or 2
Or 3 and n is 0 or 1 or 2. However, m + n is 2 or 3. The partial structure ML _m is represented by the following general formula (2), and the partial structure ML ′ _n is represented by the following general formula (3) or (4). [Chemical 1] N and C are nitrogen and carbon atoms. X and X ′ are cyclic groups which may have a substituent bonded to the metal atom M via a nitrogen atom, and Y has a substituent bonded to the metal atom M via a carbon atom. Is a good cyclic group,
Z is a cyclic group which may have a substituent. The substituents of these cyclic groups are a halogen atom, a cyano group, a nitro group, a di-substituted amino group (the substituents each independently may have a phenyl group, a naphthyl group (the substituent is a halogen atom , A methyl group, a trifluoromethyl group, or a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom) or a carbon atom. It is a linear or branched alkyl group of the formulas 1 to 8, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. },
A linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are -O-, -S-, -CO-, -CO-O.
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. A good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups or a non-adjacent group
One or more methylene groups are -O-, -S-, -CO-, -C
O-O-, -O-CO-, -CH = CH-, -C≡C-
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. ) Is shown. )
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, adjacent substituents may be bonded to each other to form a ring structure. X and Y, X and Z
Are bound by a covalent bond via an A atom or A atomic group. A is CR, N, B, SiR ',
R and R ′ each represent a hydrogen atom or an aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched group having 1 to 8 carbon atoms). An alkyl group, in which a hydrogen atom in the alkyl group may be substituted with a fluorine atom), or a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups Alternatively, two or more methylene groups which are not adjacent to each other are -O-, -S-, -CO-, -CO-O.
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. A good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (one of the alkyl groups or a non-adjacent group
One or more methylene groups are -O-, -S-, -CO-, -C
O-O-, -O-CO-, -CH = CH-, -C≡C-
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. ) Is shown. )
And a hydrogen atom in the alkyl group may be replaced by a fluorine atom. } Is selected. Y and Z are bonded by a covalent bond through an E atom or an E atomic group. E is a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms (one methylene group in the alkylene group is -O-, -S-, -CO).
-, -CO-O-, -O-CO-, -CH = CH-,-
It may be replaced by C≡C-, and the hydrogen atom in the alkylene group may be replaced by a fluorine atom. )
Chosen from. G, G'and J are each independently a linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are -O-,-; S-, -CO-, -CO-O
-, -O-CO-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a substituent. Good divalent aromatic ring group (wherein the substituent is a halogen atom, a cyano group, a nitro group, a trialkylsilyl group (the alkyl groups are each independently a linear or branched alkyl group having 1 to 8 carbon atoms) And a linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are -O-, -S-,
-CO-, -CO-O-, -O-CO-, -CH = CH
-, -C≡C- may be substituted, and the hydrogen atom in the alkyl group may be substituted with a fluorine atom. ) Is shown. Further, adjacent substituents may be bonded to each other to form a ring structure. ), The hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, A di-substituted amino group {the substituents each independently may have a phenyl group, a naphthyl group (the substituents are a halogen atom, a methyl group or a trifluoromethyl group) or carbon. It is a linear or branched alkyl group having 1 to 8 atoms, and a hydrogen atom in the alkyl group may be substituted with a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, J may be a hydrogen atom. ] 2. The metal coordination compound according to claim 1, wherein n in the general formula (1) is 0. 3. The partial structure M in the general formula (1).
L' _n is shown by the said General formula (3), The metal coordination compound of Claim 1 characterized by the above-mentioned. 4. The partial structure M in the general formula (1).
L' _n is shown by the said General formula (4), The metal coordination compound of Claim 1 characterized by the above-mentioned. 5. In the general formula (1), the partial structure ML _m represented by the general formula (2) has the following general formula (5):
To (9), the metal coordination compound according to any one of claims 1 to 4. [Chemical 2] [The cyclic group may have a substituent, and these substituents are a halogen atom, a cyano group, a nitro group, and a disubstituted amino group (the substituents may each independently have a phenyl group. Group, naphthyl group (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, and the hydrogen atom in the alkyl group is a fluorine atom). It may be substituted) or a linear or branched alkyl group having 1 to 8 carbon atoms, and a hydrogen atom in the alkyl group may be substituted with a fluorine atom. }, A linear or branched alkyl group having 1 to 20 carbon atoms {one or two or more non-adjacent methylene groups in the alkyl group are-
O-, -S-, -CO-, -CO-O-, -O-CO
-, -CH = CH-, -C≡C- may be substituted, and one or more methylene groups in the alkyl group may have a divalent aromatic ring which may have a substituent. A group (the substituent is a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (one or two or more non-adjacent methylene groups in the alkyl group are- O-, -S-, -CO-, -CO-O-, -O
It may be replaced by -CO-, -CH = CH-, -C≡C-, and the hydrogen atom in the alkyl group may be replaced by a fluorine atom. ) Is shown. ), The hydrogen atom in the alkyl group may be replaced by a fluorine atom. }, An aryl group which may have a substituent (the substituent is a halogen atom, a methyl group, a trifluoromethyl group or a linear or branched alkyl group having 1 to 8 carbon atoms, The hydrogen atom in the group may be substituted with a fluorine atom). Further, adjacent substituents may be bonded to each other to form a ring structure. ] 6. A light emitting device comprising an organic compound layer containing the metal coordination compound according to claim 1. 7. The electroluminescent device, wherein the organic compound layer containing the metal coordination compound is sandwiched between two electrodes facing each other, and emits light when a voltage is applied between the electrodes. Item 7. The light emitting device according to item 6. 8. A display device comprising the light emitting element according to claim 6 and a portion for driving the light emitting element.