JP2001052870A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently emit the blue light with excellent reliability by including a hole injection transporting compound and/or an electron injection transporting compound included in a hole transfer layer and/or an electron transfer layer as a host compound in a blue light emitting layer. SOLUTION: As a host compound to be included in a blue light emitting layer, a compound, which emits the blue light, such as a phenylanthracene derivative is desirably used. In the case where the host material of the blue light emitting layer does not have the blue light emitting characteristic, a dopant can be used so as to change the light emitting characteristic for blue light emission, and as a dopant, a styryl group amine compound or the like is used. As the blue light emitting layer, a mixture layer of an electron injection and transfer compound (A) and a hole injection and transfer compound (B) can be used. In this case, the component A and the component B can be mixed evenly, or distributed in the film thickness direction so that concentration of the component B is higher at a hole transfer layer side and that concentration of the component A is higher at the electron transfer layer side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic EL (electroluminescence) element.

[0002]

2. Description of the Related Art An organic EL device has a structure in which a thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and electrons and holes are injected into the thin film and recombined to form excitons (exciton). ), And emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated.

[0003] The organic EL element can operate at a low voltage of 10 V or less.
Surface emission with a high luminance of about 100 to 100,000 cd / m ² is possible. Further, by selecting the type of the fluorescent substance, light emission from blue to red is possible.

On the other hand, the problems of the organic EL device are that the light emission lifetime is short, the storage durability and the reliability are low. The causes are as follows: (1) Physical change of organic compound (growth of crystal domain, etc.) As a result, the interface becomes non-uniform, which causes deterioration of the charge injection capability of the device, short-circuiting, and dielectric breakdown.Especially, when a low molecular compound having a molecular weight of 500 or less is used, crystal grains appear and grow, resulting in remarkable film properties. descend.
Further, even if the interface of ITO or the like used for the anode is rough, remarkable crystal grains appear and grow, and the luminous efficiency is reduced, the current leaks, and no light is emitted. Also,
It also causes a dark spot which is a partially non-light emitting portion. )

(2) Oxidation and exfoliation of cathode (Na, K, Li, Mg, Ca, Al, etc. have been used for the cathode as a metal having a small work function in order to facilitate electron injection. These metals react with atmospheric moisture or oxygen, or peel off between the organic layer and the cathode, making it impossible to inject charges.
When a film is formed by spin coating, etc.
Moisture and decomposition products promote the oxidation reaction of the electrode, and peeling of the electrode occurs, causing a partial non-light emitting portion. )

(3) Low luminous efficiency and large amount of heat generation (Current flows through the organic compound, so the organic compound must be placed under a high electric field strength, and the heat cannot be escaped.)
Due to the heat, the element is deteriorated or destroyed due to melting, crystallization, thermal decomposition, etc. of the organic compound. )

(4) Photochemical and electrochemical changes of the organic compound layer (The organic substance is degraded by applying a current to the organic substance, causing defects such as current traps and exciton traps. Element deterioration such as reduction occurs).

As described above, the organic EL element is capable of realizing multi-color light emission. However, as an element corresponding to the multi-color light emission of the organic EL element, a stacked white light-emitting organic EL element is used.
A device has been proposed [Yoshiharu Sato, IEICE Technical Report, OME-
94-78 (1995-03)]. In this case, the light emitting layer includes a blue light emitting layer using an oxazole complex of zinc, a green light emitting layer using tris (8-quinolinolato) aluminum, and a red fluorescent dye (P-660, DCM1) on tris (8-quinolinolato) aluminum. ) Are stacked.

The inventors of the present invention have proposed that the above-mentioned devices are intended to emit light of a multicolor, since the above-described devices greatly limit the degree of freedom in material selection and adjustment of emission color. (WO98 / 08360) has been proposed. Specifically, tris (8-quinolinolato) aluminum and N, N, N ', N'-tetrakis- (3-
Adds rubrene and coumarin derivative dopants to the mixed layer with (biphenyl-1-yl) benzidine.By changing the mixing ratio and dopant type in the mixed layer, the emission characteristics can be changed and multicolor emission can be achieved. It is to be.

[0010] However, the emission colors specifically disclosed therein correspond to red to green and do not correspond to blue.

Therefore, it is desired to stably obtain a blue luminescent color. However, there is a specific problem associated therewith, and it is necessary to select not only a luminescent material but also various materials to be combined.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable organic EL device capable of efficiently obtaining blue light emission, and furthermore, to a multicolor light emission including blue light emission. Organic EL with high brightness and long life
It is to provide an element. Another object of the present invention is to provide an organic EL device which makes it possible to manufacture a multicolor organic EL display by utilizing its excellent characteristics and further combining a color filter.

[0013]

This and other objects are achieved by the present invention described below. (1) It has a light emitting layer, a hole transport layer and / or an electron transport layer adjacent to the light emitting layer, and the light emitting layer is composed of one or more layers including a blue light emitting layer, and the blue light emitting layer is An organic EL device containing the hole injection / transport compound and / or the electron injection / transport compound in the hole transport layer and / or the electron transport layer as a host compound. (2) The organic EL device according to (1), wherein the host compound is a compound that emits blue light. (3) The organic EL device according to (2), wherein the host compound is selected from a phenylanthracene derivative. (4) The organic EL device according to (1), which contains a dopant and emits blue light by the dopant. (5) The organic compound according to the above (1), which has a hole transporting layer and an electron transporting layer, and wherein the blue light emitting layer is a mixed layer of the hole injecting and transporting compound and the electron injecting and transporting compound in the hole transporting layer and the electron transporting layer. EL element. (6) The organic E according to the above (5), wherein the blue light emitting layer is a mixed layer of a phenylanthracene derivative and an aromatic tertiary amine.
L element. (7) The organic EL device according to the above (5) or (6), wherein the concentration distribution of the hole injection / transport compound and the electron injection / transport compound in the mixed layer is uniform. (8) The hole injecting and transporting compound and the electron injecting and transporting compound in the mixed layer have a concentration distribution in the film thickness direction. (5) or (6), wherein the concentration of the electron injecting and transporting compound is high. (9) The organic EL device according to any one of the above (5) to (8), which is a mixed layer further doped with a dopant. (10) The above (5) to which blue light is emitted from the entire mixed layer
The organic EL device according to any one of (9). (11) The above-mentioned (1) to (1), wherein the constituent material of the cathode provided on the electron transport layer side contains at least one compound selected from halides and oxides of alkali metals.
0) The organic EL device of any one of the above. (12) The organic EL device according to the above (11), wherein the constituent material of the cathode contains at least one compound selected from halides of Rb and Cs. (13) a cathode, one or more light-emitting layers including a blue light-emitting layer, a hole transport layer and / or an injection layer,
An organic EL device having an anode and wherein the constituent material of the cathode contains at least one compound selected from halides and oxides of alkali metals. (14) The organic EL device according to (13), wherein the blue light-emitting layer contains a phenylanthracene derivative as a compound that emits blue light. (15) The organic EL device according to the above (13) or (14), wherein the hole transporting and / or injecting layer contains an aromatic tertiary amine. (16) The aromatic tertiary amine is represented by the formula (1) and the formula (2)
The organic EL of the above (15) selected from the compounds represented by
element.

[0014]

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[In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ each represent an aryl group, an alkyl group, an alkoxy group, an aryloxy group or a halogen group;
₁ , r ₂ , r ₃ and r ₄ are each an integer of 0 to 5, and when r ₁ , r ₂ , r ₃ and r ₄ are each an integer of 2 or more, adjacent R _{1 s} and R ₂ Each other, R ₃ and R ₄
And each other may be bonded to each other to form a ring.
R ₅ and R ₆ are each an alkyl group, an alkoxy group, an amino group, or a halogen group, r ₅ and r
₆ is an integer of 0 to 4 respectively. ]

[0016]

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[In the formula (2), φ represents a phenylene group, and R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ represent an alkyl group, an aryl group, a diarylaminoaryl group,

[0018]

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Wherein at least one of R _{01 to} R ₀₄ is a diarylaminoaryl group or (a)
-1) to (a-3). r ₀₁ , r ₀₂ , r
₀₃ and r ₀₄ are each an integer of 0 to 5, and r ₀₁ +
r ₀₂ + r ₀₃ + r ₀₄ is an integer of 1 or more. r ₀₁ , r ₀₂ ,
When r ₀₃ and r ₀₄ are each an integer of 2 or more,
Adjacent R ₀₁ together, R ₀₂ together, R ₀₃ and between R ₀₄ each other, may form a ring by combining with each other. (17) a hole injection layer and a hole transport layer, wherein the hole injection layer on the anode side contains the compound represented by the formula (2), and the hole transport layer on the light emitting layer side is represented by the formula (1) The organic EL device according to the above (15) or (16), comprising a compound as described above. (18) In addition to the blue light emitting layer, the above (1) to (1) having at least one light emitting layer having a different emission wavelength from the blue light emitting layer.
The organic EL device according to any one of 7). (19) The organic EL device according to the above (18), wherein at least one light emitting layer having a different emission wavelength from the blue light emitting layer is a mixed layer of a hole injection / transport compound and an electron injection / transport compound. (20) The organic EL device according to the above (19), which is a mixed layer further doped with a dopant. (21) The above (18) to (2) having two light emitting layers
0) The organic EL device of any one of the above. (22) The above (18) to (2) having three light-emitting layers.
0) The organic EL device of any one of the above. (23) The organic EL device according to the above (21) or (22), which emits white light. (24) The above (1) to (4) to modulate the emission color by using a color filter and combining with the color filter.
The organic EL device according to any one of (23). (25) A pair of electrodes, at least one of which is opposed to each other, is transparent. An organic layer including the light emitting layer is sandwiched between the pair of electrodes, and the color filter is provided on the transparent electrode side of the pair of electrodes. (24) where is installed
Organic EL device. (26) each having a plurality of electrodes, having at least one pair of transparent XY matrix type electrodes arranged at positions crossing each other and facing each other, wherein the light emitting layer is provided between the crossed electrodes; (2) wherein the organic layer containing the organic EL element is sandwiched, and the intersection forms a pixel, and the color filter is provided on the transparent electrode side of the pixel.
4) The organic EL device. (27) The organic EL device according to the above (26), wherein a black matrix is provided in a peripheral portion of the pixel and near a portion where the color filter is provided.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The organic EL device of the present invention has a blue light-emitting layer using a hole injection / transport compound and / or an electron injection / transport compound in a hole transport layer and / or an electron transport layer adjacent to a light emitting layer as a host material. Alternatively, it has a blue light-emitting layer and uses a compound selected from alkali metal chlorides and oxides as a cathode material. Preferably, those having both of these configurations,
The blue light emitting layer is preferably a mixed layer of the above-described hole injecting and transporting compound and the electron injecting and transporting compound. Further details will be described.

<Blue light emitting layer> The organic EL device of the present invention has a blue light emitting layer. In this case, a phenylanthracene derivative is preferably used as the compound that emits blue light. These are described in JP-A-8-12600. Among them, the compound represented by the formula (A) is preferable as the phenylanthracene derivative. A ₁ -LA ₂ (A)

In the formula (A), A ₁ and A ₂ each represent a mono (ortho-substituted phenyl) anthryl group or a di (ortho-substituted phenyl) anthryl group, which may be the same or different. L represents a single bond or a divalent linking group.

The mono (ortho-substituted phenyl) phenylanthryl group or di (ortho-substituted phenyl) phenylanthryl group represented by A ₁ or A ₂ is bonded to the 2- or 6-position of the phenyl group (the bonding position to the anthracene ring). At the ortho position with respect to), an aryl group, a heteroaromatic ring group or an arylethenyl group. Further, it may have a substituent other than the ortho position, and when the compound has a substituent, examples of the substituent include an alkyl group, an aryl group, an arylethenyl group, an alkoxy group, and an amino group. May be further substituted. These substituents will be described later.

It is preferable that the position of the phenyl group in the anthracene ring is 9-position or 10-position of the anthracene ring.

In the formula (A), L represents a single bond or a divalent group, and the divalent group represented by L is preferably an arylene group optionally interposed with an alkylene group or the like. Such an arylene group will be described later.

Among the phenylanthracene derivatives represented by the formula (A), those represented by the formulas (A-1) and (A-2) are preferable.

[0027]

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[0028]

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In the formula (A-1), Ar _{1 to} Ar
₄ represents a hydrogen atom, an aryl group, a heteroaromatic ring group or an arylethenyl group, and at least one of Ar ₁ and Ar ₂ and at least one of Ar ₃ and Ar ₄ are an aryl group and a heteroaromatic ring group, respectively. Or an arylethenyl group. R ₅₁ and R ₅₂ each represent an alkyl group, an aryl group, an arylethenyl group, an alkoxy group,
Or an amino group, which may be the same or different. p1 and p2 each represent an integer of 0 to 3, and when p1 and p2 are each an integer of 2 or more, R ₅₁ and R ₅₂ may be the same or different. R ₅₃ represents an alkyl group or an aryl group, and p3 represents an integer of 0 to 3, respectively. p3
Is an integer of 2 or more, R ₅₃ may be the same or different. L ₁ represents a single bond or an arylene group, wherein the arylene group is an alkylene group, —O—, —S
-Or -NR- (where R represents an alkyl group or an aryl group) may be present.

In the formula (A-2), Ar ₅ and Ar
₆ are each a hydrogen atom, an aryl group, a heteroaromatic ring group or Arirueteniru group, at least one of Ar ₅ and Ar ₆ is an aryl group, a heteroaromatic ring group or Arirueteniru group. R ₅₄ represents an alkyl group, an aryl group, an arylethenyl group, an alkoxy group, or an amino group, which may be the same or different. p4 each represents an integer of 0 to 3, p4 are each time an integer of 2 or more, R ₅₄ each other may be the same or different in the same. R ₅₅ represents an alkyl group or an aryl group, and p5 represents an integer of 0 to 4, respectively. When p5 is an integer of 2 or more, each of R ₅₅ may be the same or different. L ₂ represents a single bond or an arylene group, wherein the arylene group is an alkylene group, —O
-, -S- or -NR- (where R represents an alkyl group or an aryl group) may be present. L ₂ represents a single bond or an arylene group, wherein the arylene group is an alkylene group, —O—, —S—, or —NR—
(Here, R represents an alkyl group or an aryl group.)
May be interposed.

The aryl group represented by Ar _{1 to} Ar ₄ and R _{51 to} R ₅₃ is preferably an aryl group having 6 to 20 carbon atoms, and further has a substituent such as a phenyl group and a tolyl group. Is also good. Specifically, a phenyl group, (o
-, M-, p-) tolyl group, pyrenyl group, naphthyl group,
Anthryl group, biphenyl group, phenylanthryl group,
And a toryl anthryl group.

Examples of the heteroaromatic ring group represented by Ar _{1 to} Ar ₄ include a furyl group, a benzofuryl group, a thienyl group, a bithienyl group, a benzothienyl group, a pyrrolyl group, an N-allylpyrrolyl group, an indolyl group, a pyridyl group and a bipyridyl group. Group,
Quinolyl group, quinoxalyl group, oxazole group, benzoxazole group, oxadiazole group, thiazole group,
A benzothiazole group, a thiadiazole group, an imidazole group and the like are preferable, and further, a substituent such as an aryl group having 42 or less carbon atoms, an alkyl group having 12 or less carbon atoms, an alkoxy group, an aryloxy group, an amino group, a cyano group, and a nitro group. May be provided. Specifically, as a substituent, a phenyl group, an (o-, m-, p-) biphenyl group,
(1,2) Naphthyl group, methyl group, ethyl group, propyl group, butyl group, methoxy group, ethoxy group, phenoxy group, (o-, m-, p-) tolyl group and the like.

The arylethenyl group represented by Ar _{1 to} Ar ₄ , R ₅₁ and R ₅₂ is preferably a 2-phenylethenyl group, a 2,2-diphenylethenyl group, and the like. It may have a substituent such as a group, an alkoxy group, an aryloxy group, an amino group, a cyano group or a nitro group. Specifically, as a substituent,
Phenyl group, (o-, m-, p-) biphenyl group,
(1,2) Naphthyl group, methyl group, ethyl group, propyl group, butyl group, methoxy group, ethoxy group, phenoxy group, (o-, m-, p-) tolyl group and the like.

The alkyl group represented by R _{51 to} R ₅₃ may be linear or branched, and may be a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or 1 to 4 carbon atoms. Is preferred. In particular, an unsubstituted alkyl group having 1 to 4 carbon atoms is preferable, and specifically, a methyl group, an ethyl group,
(N-, i-) propyl group, (n-, i-, s-, t
-) Butyl group and the like.

The alkoxy group represented by R ₅₁ and R ₅₂ preferably has 1 to 6 carbon atoms in the alkyl group, and specific examples include a methoxy group and an ethoxy group. The alkoxy group may be further substituted.

The amino group represented by R ₅₁ and R ₅₂ may be unsubstituted or substituted, but preferably has a substituent. In this case, the substituent is preferably an alkyl group (methyl Group, an ethyl group, etc.) and an aryl group (a phenyl group, etc.). Specific examples include a diethylamino group, a diphenylamino group, and a di (m-tolyl) amino group.

In the formula (A-1), p1 and p2
Represents an integer of 0 or an integer of 1 to 3;
It is preferable that p1 and p2 are each 1 to
When it is an integer of 3, especially 1 or 2, R ₅₁ and R ₅₂
Is preferably a methyl group or a phenyl group, respectively.

In the formula (A-1), p3 is 0
Represents an integer of 3 to 3, and particularly preferably 0 to 2. When p3 is an integer of 1 to 3, especially 1 or 2, _R53 is preferably a methyl group or a phenyl group, respectively.

In the formula (A-1), R₅₁~ R₅₃Are the same
But may be different, R ₅₁, R₅₂And R₅₃And
When there are a plurality of each, R₅₁Each other, R₅₂Each other, R₅₃Each other
May be the same or different.

In the formula (A-1), L ₁ represents a single bond or an arylene group. The arylene group represented by L ₁ is preferably unsubstituted. Specifically, in addition to a normal arylene group such as a phenylene group, a biphenylene group, an anthrylene group, two or more arylene groups may be directly substituted. And linked ones. L ₁ is preferably a single bond, a p-phenylene group, a 4,4′-biphenylene group or the like.

The arylene group represented by L ₁ is 2
One or more arylene groups are alkylene groups, -O
-, -S- or -NR- may be interposed and linked. Here, R represents an alkyl group or an aryl group. Examples of the alkyl group include a methyl group and an ethyl group, and examples of the aryl group include a phenyl group. Among them, an aryl group is preferable, and in addition to the above-mentioned phenyl group, A ₁ and A ₂ may be used, and further, a phenyl group substituted with A ₁ or A ₂ may be used.
Further, as the alkylene group, a methylene group, an ethylene group and the like are preferable. Specific examples of such an arylene group are shown below.

[0042]

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Next, the equation (A-2) will be described.
In the formula (A-2), R ₅₄ is the same as R in the formula (A-1)
₅₁ or R ₅₂ and R ₅₅ are the same as R ₅₃ in formula (A-1).
If, p4 and p1 or p2 in formula (A-1), further L ₂ have the same meanings as L ₁ in formula (A-1), preferable ones are also same.

In the formula (A-2), p5 is an integer of 0 to 4, and preferably 0 to 2. p5 is each an integer of 1 to 3, especially 1 or 2
In the formula, R ₅₅ is preferably a methyl group or a phenyl group, respectively.

The formula (A-2), may be one that is different even in the same and R ₅₄ and R _55, when R ₅₄ and R ₅₅ there are a plurality each of each other R _54, R ₅₅ together are each They may be the same or different.

In the formula (A-1), Ar ₁ and Ar
₂ , at least one of Ar ₃ and Ar ₄ is a phenyl group, a biphenyl group, a terphenyl group, a styryl group, a phenylstyryl group, a diphenylstyryl group, a thienyl group, a methylthienyl group, a phenylthienyl group or a phenylbithienyl group It is preferred that
Further, at least one of Ar ₁ and Ar ₂ , Ar ₃
And at least one of Ar ₄ is a phenyl group, a biphenyl group or a terphenyl group, and L ₁ is preferably a single bond.

In the formula (A-2), Ar ₅ and Ar
_It is preferable that at least one of ₆ is phenyl, biphenyl, terphenyl, styryl, phenylstyryl, diphenylstyryl, thienyl, methylthienyl, phenylthienyl or phenylbithienyl. Further, it is preferable that at least one of Ar ₅ and Ar ₆ is a phenyl group, a biphenyl group or a terphenyl group, and L ₂ is a single bond.

The compounds represented by formulas (A-1) and (A-2) are exemplified below, but the present invention is not limited thereto. Here, it is shown by a combination of the formula and the group,
When indicated collectively by R _{32 -37,} etc. denote the only substituent, all the time of the hydrogen atoms are indicated by -H. Abbreviations are indicated as appropriate (Note that Toly is a tolyl group).

[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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For a method for synthesizing the phenylanthracene derivative of the present invention, reference can be made to JP-A-8-12600.

These compounds may be used alone or in combination of two or more.

When a phenylanthracene derivative is used as the blue light emitting compound and the blue light emitting layer is formed, the thickness is preferably 1 to 500 nm, more preferably 10 to 200 nm.
nm.

Such a light emitting layer may be doped with a dopant so as to maintain blue light emission. Examples of such dopants include WO98 / 08360 and JP-A-8-2396.
No. 55, a styryl-based amine compound and the like.
The styryl amine compound will be described later. The amount of the dopant used is preferably 0.1 to 20% by mass in the light emitting layer. The use of the dopant improves luminous efficiency and device stability.

The blue light emitting layer may contain an electron transporting compound or a hole injection transporting compound used as an electron transporting layer or a hole transporting layer provided adjacent to the light emitting layer as a host material. . Specifically, the use of a phenylanthracene derivative used for the electron transport layer as a host material may be mentioned. Since the phenylanthracene derivative has blue light-emitting properties, it can emit blue light by itself, but when the host material does not have blue light-emitting properties,
Light emission characteristics may be changed by using a dopant to emit blue light. Such dopants include the styryl amine compounds described above.

In such a structure, the thickness ratio of the thickness of the electron transporting layer or hole transporting layer containing the compound to be the host material to the thickness of the light emitting layer is expressed by the following equation. / 1 is preferable.

The blue light emitting layer may be a mixed layer of an electron injecting and transporting compound and a hole injecting and transporting compound,
Such an embodiment is preferred. Of these, one of the electron injecting / transporting compound and the hole injecting / transporting compound is preferably the same as the compound used for the electron transporting layer and the hole transporting layer provided adjacent to the light emitting layer. Particularly preferably, an electron transporting layer and a hole transporting layer are provided adjacent to the light emitting layer, and an electron injecting and transporting compound and a hole injecting and transporting compound in these layers are used to form a mixture of these compounds. is there.

Specifically, it is preferable to use a phenylanthracene derivative in the electron transporting layer as the electron injecting and transporting compound, and to use an aromatic tertiary amine in the hole transporting layer as the hole injecting and transporting compound. As the phenylanthracene derivative, the compound of the above formula (A) is preferable. As the aromatic tertiary amine, a tetraarylbenzidine derivative represented by the formula (1) is preferable.

[0087]

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Describing the equation (1), R _{1 to} R ₄
Is an aryl group, an alkyl group, an alkoxy group,
Represents an aryloxy group or a halogen group, which may be the same or different. r _{1 to} r ₄ are each an integer of 0 to 5, and when r _{1 to} r ₄ are each an integer of 2 or more, adjacent R _{1 s} , R _{2 s} , R _{3 s} ,
R _{4 's} may be bonded to each other to form a ring. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen group, which may be the same or different. r ₅ and r ₆ are each an integer of 0 to 4.

The aryl groups represented by R _{1 to} R ₄ may be monocyclic or polycyclic, and include condensed rings and ring assemblies. The total carbon number is preferably 6 to 20, and may have a substituent. Examples of the substituent in this case include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, and a halogen atom.
Specifically, phenyl group, (o-, m-, p-) tolyl group, pyrenyl group, perylenyl group, coronenyl group, naphthyl group, anthryl group, biphenylyl group, phenylanthryl group, tolyl anthryl group, etc. The phenyl group is particularly preferred, and the bonding position of the aryl group, particularly the phenyl group, may be the 3-position (meta-position to the N-bonding position) or the 4-position (para-position to the N-bonding position). preferable.

The alkyl group represented by R _{1 to} R ₄ may be linear or branched, preferably has 1 to 10 carbon atoms, and may have a substituent. . In this case, examples of the substituent include those similar to the aryl group. Specifically, a methyl group, an ethyl group, (n
-, I-) propyl group, (n-, i-, s-, t-) butyl group and the like.

The alkoxy group represented by R _{1 to} R ₄ is preferably an alkoxy group having 1 to 6 carbon atoms in the alkyl portion, and specific examples include a methoxy group, an ethoxy group and a t-butoxy group. The alkoxy group may be further substituted.

The aryloxy groups represented by R _{1 to} R ₄ include a phenoxy group, a 4-methylphenoxy group,
(T-butyl) phenoxy group and the like.

Examples of the halogen group represented by R _{1 to} R ₄ include a chlorine atom and a bromine atom.

In the formula (1), in a preferred embodiment, any of r _{1 to} r ₄ is an integer of 2 or more, and R ₁ to R ₂ , R _{3 to} R ₄ and R _{4 to} R ₄ There is a case where any one of them is bonded to each other to form a ring (for example, a benzene ring).

In another preferred embodiment, R _{1 to} R
_At least one of ₄ is an aryl group. That is, r _{1 to} r ₄ do not become 0 at the same time.
Therefore, r ₁ + r ₂ + r ₃ + r ₄ is an integer of 1 or more, and is a number satisfying the condition that at least one aryl group exists.

When at least one of R _{1 to} R ₄ is an aryl group, it is particularly preferable that there are 2 to 4 aryl groups in one molecule as R _{1 to} R ₄ , and r _{1 to} r ₄
Is preferably an integer of 1 or more.
In particular, the aryl groups are present 2-4 in total in a molecule, preferably 2 to 4 is 1 in r ₁ ~r _4, more preferably from r ₁ ~r ₄ is 1, included It is also preferred that all of R _{1 to} R ₄ are aryl groups. That is, a total of 2 to 4 aryl groups are present in the 4 benzene rings which may be substituted by R _{1 to} R ₄ in the molecule, and the 2 to 4 aryl groups are 4 benzene rings. May be bonded to the same or different ones, but it is particularly preferable that 2 to 4 aryl groups are respectively bonded to different benzene rings. And it is more preferable that at least two aryl groups are bonded to the N-position at the para-position or the meta-position. In this case, it is preferable that at least one aryl group is a phenyl group, that is, it is preferable that the aryl group and a benzene ring are combined to form a 4- or 3-biphenylyl group with respect to the N atom. It is particularly preferred that 2 to 4 are 4- or 3-biphenylyl groups. One or both of the 4- or 3-biphenylyl groups may be mixed. In addition, examples of the aryl group other than the phenyl group include (1-, 2-) naphthyl group, (1-, 2-, 9
-) An anthryl group, a pyrenyl group, a perylenyl group, a coronenyl group, and the like are preferable, and an aryl group other than the phenyl group is also preferably bonded to the N-position at the para-position or the meta-position. These aryl groups may be mixed with the phenyl group.

In the formula (1), the alkyl group, alkoxy group and halogen atom represented by R ₅ and R ₆ are R
_{The same} ones as those described for _{1 to} R ₄ can be mentioned.

As the amino groups represented by R ₅ and R ₆ ,
It may be unsubstituted or may have a substituent, but those having a substituent are preferable.Specifically, a dimethylamino group, a diethylamino group, a diphenylamino group, a ditolylamino group, a dibiphenylylamino group, an N-phenyl -N
-Tolylamino group, N-phenyl-N-naphthylamino group, N-phenyl-N-biphenylylamino group, N-phenyl-N-anthrylamino group, N-phenyl-N-
Examples include a pyrenylamino group, a dinaphthylamino group, a dianthrylamino group, a dipyrenylamino group, and the like.

Preferably, r ₅ and r ₆ are both 0, and the biphenylene group connecting two arylamino groups is preferably unsubstituted.

When r _{1 to} r ₄ are integers of 2 or more, each of R _{1 to} R ₄ may be the same or different. Further, when r _5, r ₆ is an integer of 2 or more, R ₅ to each other,
R ₆ may be the same or different.

Among these compounds, the following formula (1-
The compound represented by 1) is preferred.

[0102]

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[0103] formula will be described. (1-1), A ₁₁ ~
A ₁₄ is in the para position (position 4) with respect to the bonding position of N.
Or a phenyl group or a hydrogen atom bonded to the meta position (3 position), which may be the same or different. However, two or more of A _{11 to} A ₁₄ are preferably phenyl groups. These phenyl groups may further have a substituent. In this case, the substituents may be R ₁ to R _{1.
The same} substituents as those described for the aryl group represented by ₄ can be exemplified.

R _{7 to} R ₁₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group or a halogen group, which may be the same or different. Specific examples thereof include the same ones as those described for R _{1 to} R _{4 in} the formula (1).

R _{7 to} r ₁₀ are each an integer of 0 to 4, and r _{7 to} r ₁₀ are preferably 0.

When r _{7 to} r ₁₀ are each an integer of 2 or more, R _{7 to} R ₁₀ may be the same or different.

In the formula (1-1), R ₅ ,
R ₆ , r ₅ and r ₆ have the same meanings as in formula (1),
It is preferred that ₅ = r ₆ = 0.

Specific examples of the compound represented by the formula (1) are shown below, but the present invention is not limited thereto. Specific examples are shown according to the expressions (I) and (II).
When H is H in all of _{1 to} R _{4 and the} like, it is indicated by H, and when a substituent is present, only the substituent is indicated. In addition, N, N'-di (1-naphthyl) -N, N 'used in Examples
-Diphenylbenzidine.

[0109]

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[0110]

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[0111]

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[0112]

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[0113]

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[0114]

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The tetraarylbenzidine derivatives represented by the formula (1) may be used alone or in combination of two or more.

The mixing ratio (volume ratio) of the electron injecting / transporting compound to the hole injecting / transporting compound in the mixed layer is 10/90 for the electron injecting / transporting compound / the hole injecting / transporting compound.
90/10, more preferably 2/10.
0/80 to 80/20.

In the case where the above-mentioned phenylanthracene derivative is used as the electron transporting compound in such a mixed layer, it can be used as a blue light emitting compound. When the phenylanthracene derivative is used as a blue light-emitting compound and mixed with a tetraarylbenzidine derivative to form a blue light-emitting layer, the phenylanthracene derivative / tetraarylbenzidine derivative (volume ratio) is 95/5 to 3%.
0/70 is preferred, and 90/10 to 40/60 is more preferred.

Further, the mixed layer as described above may be further doped with a dopant, and the doping of the dopant is preferable in view of improvement of luminous efficiency and stability of the device.
The amount of the dopant used is preferably 0.1 to 20% by mass in the mixed layer.

As such a dopant, the aforementioned styryl amine compounds are preferably used. Particularly, the compound represented by the formula (S) is preferable.

[0120]

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The equation (S) will be described.
Among, R ₆₁ represents hydrogen or an aryl group. The aryl group represented by R ₆₁ may also have a substituent, preferably has a total carbon number of 6 to 30, for example, a phenyl group and the like.

R ₆₂ and R ₆₃ each represent hydrogen, an aryl group or an alkenyl group, which may be the same or different.

The aryl group represented by R ₆₂ and R ₆₃ may have a substituent and has a total carbon number of 6 to 6.
70 is preferred. Specific examples include a phenyl group, a naphthyl group, and an anthryl group. As the substituent, an arylamino group (for example, a diphenylamino group), an arylaminoaryl group, and the like are preferable. In addition, a styryl group (a styryl group further includes a phenyl group,
Diphenylamino group, naphthyl (phenyl) amino group,
It may have a substituent such as a diphenylaminophenyl group. ) Is also preferable, and in such a case, it is also preferable that the monovalent groups derived from the compound represented by the formula (S) are bonded to each other by themselves or via a linking group. .

The alkenyl groups represented by R ₆₂ and R ₆₃ may have a substituent and have 2 to 2 carbon atoms.
50 are preferable, and a vinyl group and the like can be mentioned, and it is preferable that a styryl group is formed together with the vinyl group.
The styryl group may have a substituent such as an arylaminoaryl group (for example, a diphenylaminophenyl group) or an arylamino group (for example, a diphenylamino group). In such a case, the styryl group may be substituted with a compound represented by the formula (S). It is also preferable that the monovalent groups to be derived have a structure in which the monovalent groups are bonded by themselves or via a linking group.

R ₆₄ and R ₆₅ each represent an arylamino group or an arylaminoaryl group, which may contain a styryl group (the styryl group may further have a substituent such as a phenyl group). Well, in such a case,
As described above, it is also preferable that the monovalent groups derived from the compound represented by the formula (S) have a structure in which the monovalent groups are bonded to each other by themselves or via a linking group.

[0126] _v 1, _{v 2} represents an integer of 0 to _{5, v} 1,
When v ₂ is 2 or more, R ₆₄ and R ₆₅ may be bonded to each other to form a condensed ring such as a benzene ring.

R ₆₆ and R ₆₇ each represent an alkyl group or an aryl group. The alkyl group represented by R ₆₆ or R ₆₇ may have a substituent, may be linear or branched, and preferably has 1 to 6 carbon atoms. Include a methyl group and an ethyl group. R ₆₆ ,
The aryl group represented by R ₆₇ may have a substituent, may be monocyclic or polycyclic, and may have a total carbon number of 6 to
20 are preferred, and specific examples include a phenyl group.

V ₃ and v _{4 each} represent an integer of 0-4.

V ₅ represents 0 or 1. In the formula (S), v ₅ is 0, and a diphenylamino group to which R ₆₄ and R ₆₅ may be bonded, and R ₆₁ , R ₆₂ and R
A structure in which the vinyl group bonded to ₆₃ is bonded to the phenylene group at the para position is preferable.

In particular, compounds represented by the following formulas (S-1) and (S-2) are preferred.

[0131]

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In the formula (S-1), R ₆₁ , R ₆₂ ,
R ₆₄ , R ₆₅ , v ₁ and v ₂ have the same meanings as those in formula (S), n1 represents 0 or 1, and L ₆₁ represents a bond or an arylene group. Preferred specific examples of the arylene group include a phenylene group, a biphenylene group, a naphthylene group, an anthrylene group, and the like, and a combination thereof is also preferable. These groups may further have a substituent.

In the formula (S-2), R _{61 to} R ₆₃ ,
R ₆₅ and v ₂ have the same meanings as those in the formula (S), n2 represents 0 or 1, and L ₆₂ has the same meaning as L ₆₁ in the formula (S-1).

Specific examples of the styryl amine compound of the formula (S) are shown below.

[0135]

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[0136]

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These compounds may be used alone or in combination of two or more.

In the mixed layer as described above, it is preferable to select an electron injecting / transporting compound and a hole injecting / transporting compound such that the product of the charge mobility and the charge density becomes substantially equal. More preferably, the above conditions are satisfied and the charge mobilities are preferably substantially equal. In this case, the charge mobility is obtained by a time-of-flight method or the like, and is preferably in the range of 1 × 10 ⁻¹ to 1 × 10 ⁻⁵ cm ² / V · s. By selecting a compound such that the charge mobility becomes closer, i) increasing the recombination probability of carriers improves luminous efficiency, and ii) penetration of carriers from the luminescent layer is reduced, and carriers are reduced. There is an advantage that the damage of the transport layer is reduced and the light emission lifetime of the device can be extended. Further, by mixing the hole injecting and transporting compound and the electron injecting and transporting compound, there are advantages that the mobility of each electron and hole is reduced and the recombination probability is improved.

In the mixed layer, the electron injecting and transporting compound and the hole injecting and transporting compound may be uniformly mixed, have a concentration distribution in the film thickness direction, and have a concentration distribution in the hole transporting layer side. A gradient film having a high concentration and gradually decreasing its concentration toward the electron transport layer side, while having a high concentration of the electron injecting and transporting compound at the electron transport layer side and gradually decreasing its concentration toward the hole transport layer side. Good. In the gradient film, the electron injecting and transporting compound is preferably present in about １ ／ to 50% by mass of the electron injecting and transporting compound present in the entire mixed layer in a half region of the mixed layer on the electron transporting layer side. It is preferable that the same relationship is established also for the acidic compound.

In the blue light-emitting layer composed of the above-described mixed layer, electrons and holes are distributed throughout the light-emitting layer, recombination points and light-emitting points are spread throughout the light-emitting layer, and only in the vicinity of the interlayer interface. Instead, light is emitted from the entire mixed layer. This can be easily confirmed by fitting an actually measured emission spectrum and an emission spectrum obtained by performing an optical interference simulation of reflected light at each optical interface and direct light assuming an emission region. Since light can be emitted from the entire layer in this manner, several kinds of light emission having different wavelengths stacked can be stably extracted from one element, and advantages such as extending the light emission life of the element can be obtained.

The emission maximum wavelength of the blue light emitting layer in the present invention is 400 to 500 nm.

The thickness of the mixed layer as described above is 1 to 500 n
m, more preferably 20 to 200 nm.

<Other Light Emitting Colors> The organic EL device of the present invention may correspond to multicolor light emission having at least one light emitting layer having a different light emission wavelength in addition to the blue light emitting layer. preferable. Such a light emitting layer includes red (a maximum emission wavelength of 600 to 700 nm) and green (a maximum emission wavelength of 500 nm).
560 nm).

In these light emitting layers, it is preferable to form a mixed layer using the same host material as the blue light emitting layer, and to emit light of a color different from blue by adding a dopant. This expands the recombination region, which is preferable for the generation of excitons.

For example, as a preferable embodiment of such a mixed layer, there is a mixed layer obtained by doping a mixture of the phenylanthracene derivative and the tetraarylbenzidine derivative with a naphthacene derivative as a dopant. For example, when rubrene is used as the naphthacene derivative, red (emission maximum wavelength: 540 to 600 nm) light emission becomes possible. The addition of the naphthacene derivative is preferable from the viewpoint of extending the life of the device. In addition, a pentacene derivative has the same advantages. These are disclosed in JP-A-8-31442.
Publication, WO98 / 08360, Japanese Patent Application No. 10-137
No. 505, etc.

As the naphthacene derivative, a compound represented by the formula (N) is preferable.

[0147]

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In the formula (N), R _a , R _b , R _c and R _d each represent any of unsubstituted or substituted alkyl, aryl, amino, heterocyclic and alkenyl groups. , An aryl group, an amino group, a heterocyclic group and an alkenyl group.

The aryl group represented by R _a , R _b , R _c and R _d may be monocyclic or polycyclic,
Fused rings and ring assemblies are also included. The total carbon number is preferably 6 to 30, and may have a substituent.

The aryl group represented by R _a , R _b , R _c and R _d is preferably a phenyl group, (o-, m-,
p-) tolyl group, pyrenyl group, perylenyl group, coronenyl group, (1-, 2-) naphthyl group, anthryl group, (o
-, M-, p-) biphenylyl group, terphenyl group, phenanthryl group and the like.

The amino group represented by R _a , R _b , R _c and R _d may be any of an alkylamino group, an arylamino group, an aralkylamino group and the like. These preferably have an aliphatic having 1 to 6 carbon atoms in total and / or 1 to 4 aromatic carbon rings. Specific examples include a dimethylamino group, a diethylamino group, a dibutylamino group, a diphenylamino group, a ditolylamino group, a bisdiphenylylamino group, and a bisnaphthylamino group.

The heterocyclic groups represented by R _a , R _b , R _c and R _d include those containing O, N and S as hetero atoms.
Membered or 6-membered aromatic heterocyclic group, and having 2 to 2 carbon atoms
And 0 fused polycyclic aromatic heterocyclic groups. Examples of the aromatic heterocyclic group and the condensed polycyclic aromatic heterocyclic group include a thienyl group, a furyl group, a pyrrolyl group, a pyridyl group, a quinolyl group, and a quinoxalyl group.

The alkenyl groups represented by R _a , R _b , R _c and R _d include (1- and 2-) phenylalkenyl groups having at least one of the substituents having a phenyl group,
Preferred are (1,2- and 2,2-) diphenylalkenyl groups, (1,2,2-) triphenylalkenyl groups and the like, but they may be unsubstituted.

When R _a , R _b , R _c and R _d have a substituent, at least two of these substituents are any of an aryl group, an amino group, a heterocyclic group, an alkenyl group and an aryloxy group. Preferably, there is. Aryl group, an amino group, the heterocyclic group and the alkenyl group is the same as above R _a, R _b, R _c and R _d.

As the aryloxy group which is a substituent of R _a , R _b , R _c and R _d , an aryloxy group having an aryl group having a total of 6 to 18 carbon atoms is preferable. Specifically, (o-, m-, p
-) Phenoxy group and the like.

Two or more of these substituents may form a condensed ring. Further, it may be further substituted, and in that case, preferred substituents are the same as described above.

When R _a , R _b , R _c and R _d have a substituent, it is preferred that at least two of them have the above substituent. The substitution position is not particularly limited, and may be any of meta, para and ortho positions.
Furthermore, R _a and R _d, although it is preferred that R _b and R _c is the same as each may be different.

R _e , R _f , R _g and R _h each represent hydrogen or an optionally substituted alkyl, aryl, amino or alkenyl group.

The alkyl group represented by R _e , R _f , R _g and R _h preferably has 1 to 6 carbon atoms, and may be linear or branched. Preferred specific examples of the alkyl group include a methyl group, an ethyl group, (n,
i) -propyl group, (n, i, sec, tert) -butyl group, (n, i, neo, tert) -pentyl group and the like.

The aryl group, amino group and alkenyl group represented by R _e , R _f , R _g and R _h include the above-mentioned R _a ,
The same as in the case of R _b , R _c and R _d . Also, R _e and R
_f , R _g and R _h are preferably the same, but may be different.

Specific examples of the naphthacene derivative are shown below.
A specific example is shown by a combination of the expressions (N).

[0162]

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[0163]

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[0164]

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[0165]

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These compounds may be used alone or in combination of two or more.

The amount of the naphthacene derivative used in the mixed layer is preferably 0.1 to 20% by mass.

The mixing ratio of the phenylanthracene derivative to the tetraarylbenzidine derivative in such a mixed layer is such that the volume ratio of the phenylanthracene derivative / tetraarylbenzidine derivative is 90/10 to 10/9.
It is preferably 0. The thickness is preferably 1 to 500 nm, more preferably 10 to 200 nm.

In the present invention, two or three light-emitting layers including a blue light-emitting layer can be provided to constitute a device which emits white light.

<Hole Transport and / or Injection Layer> In the present invention, although partially described above, it is preferable to provide a hole transport and / or injection layer. A hole transporting layer and / or a hole transporting and / or injecting layer (also referred to as a hole injecting and transporting layer) is provided even in a case where the hole injecting and transporting compound in the layer is not used as a host material of the light emitting layer. Is preferred. As the hole injecting and transporting compound in this case, an aromatic tertiary amine is preferably used, and a tetraarylbenzidine derivative represented by the formula (1) and a triphenylamine derivative represented by the formula (2) are preferred. Equation (1) is as described above. Equation (2) will be described.

[0171]

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In the formula (2), two Φs represent a phenylene group. As the biphenylene group of Φ-Φ, 4,4 ′
-Biphenylene group, 3,3'-biphenylene group, 3,
4′-biphenylene group, 2,2′-biphenylene group,
Any of a 2,3′-biphenylene group and a 2,4′-biphenylene group may be used, and a 4,4′-biphenylene group is particularly preferable.

R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ each represent an alkyl group, an aryl group, a diarylaminoaryl group,

[0174]

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And these may be the same or different. However, at least one of R _{01 to} R ₀₄ is a diarylaminoaryl group or (a)
-1) to (a-3). R ₀₁₁ , R ₀₁₂ ,
The aryl groups represented by R ₀₁₃ , R ₀₁₄ , R ₀₁₅ , R ₀₁₆ and R ₀₁₇ may each be unsubstituted or substituted.

The alkyl groups represented by R ₀₁ , R ₀₂ , R ₀₃ , and R ₀₄ may have a substituent, may be linear or branched, and have a total carbon number of 1 to 20. Are preferred,
Specific examples include a methyl group and an ethyl group.

R ₀₁ , R ₀₂ , R ₀₃ , R ₀₄ , R ₀₁₁ , R ₀₁₂ ,
The aryl group represented by R ₀₁₃ , R ₀₁₄ , R ₀₁₅ , R ₀₁₆ and R ₀₁₇ may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms. ,
Examples include phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, perylenyl and o-, m- or p-biphenyl. These aryl groups may be further substituted. Examples of such a substituent, an aryl group or an alkoxy group having an alkyl group, an unsubstituted or substituted group having 1 to 6 carbon atoms, an aryloxy group, and -N (R ₀₂₁ ) _{R022 and the} like. Here, R ₀₂₁ and R ₀₂₂ each represent an unsubstituted or substituted aryl group.

The aryl group represented by R ₀₂₁ and R ₀₂₂ may be a monocyclic or polycyclic aryl group, preferably having 6 to 20 carbon atoms, and specifically includes a phenyl group,
Examples include a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a perylenyl group, an o-, m- or p-biphenyl group, and particularly preferably a phenyl group. These aryl groups may be further substituted, and examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, an unsubstituted or substituted aryl group, and the like. The alkyl group is preferably a methyl group, and the aryl group is preferably a phenyl group.

The diarylaminoaryl group represented by R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ is, for example, a diarylaminophenyl group. In such a group, the diarylamino group is represented by the formula (2). Those bonded at the meta position (3 position) or para position (4 position) with respect to the skeleton are preferred. The phenyl group at this time may further have a substituent, but preferably has only a diarylamino group.

The aryl group in the diarylamino group may be a monocyclic or polycyclic aryl group and has a total carbon number of 6 to 6.
20 are preferred, and specific examples thereof include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a perylenyl group and an o-, m- or p-biphenyl group, and particularly preferably a phenyl group. No. These aryl groups may be further substituted, and examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, an unsubstituted or substituted aryl group, and the like. The alkyl group is preferably a methyl group, and the aryl group is preferably a phenyl group. Further, as a substituent of the aryl group,
The above groups other than the diarylaminoaryl groups represented by R _{01 to} R ₀₄ in the formula (2) are also preferable. When it has two or more substituents, they may be the same or different. Further, the substituent is preferably bonded at the meta or para position with respect to the bonding position of N.

In the equation (2), r₀₁, R₀₂, R
₀₃And r₀₄Are each 0 to 5, preferably 0 to 2
Represents an integer of 0, preferably 0 or 1.
No. And r₀₁+ R₀₂+ R₀₃+ R₀₄Is one or more, especially
1-4, more preferably 2-4. The R₀₁, R₀₂,
R₀₃And R₀₄Is a meta-position to the bonding position of N
Is attached to the para position and R₀₁, R₀₂, R₀₃And R₀₄All of
Is the meta position, R₀₁, R₀₂, R₀₃And R₀₄Is all para
Position or R₀₁, R₀₂, R₀₃And R₀₄Is meta
Or they are mixed at the para position
Is also good. r₀₁, R₀₂, R₀₃Or r₀₄Is more than 2
If R₀₁Each other, R₀₂Each other, R₀₃Each other or R ₀₄Same
May be one or different and even these adjacent
They may be bonded to each other to form a ring. This
The ring is an aromatic ring such as a benzene ring.
It may be an aliphatic ring such as a hexane ring.

Preferred examples of the formula (2) are shown below, but the invention is not limited thereto.

[0183]

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[0184]

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These may be used alone or in combination of two or more.

When a hole transport layer and a hole injection layer are sequentially provided from the light emitting layer side, it is preferable to use the compound of the formula (1) for the hole transport layer and the compound of the formula (2) for the hole injection layer. By combining such compounds, the function of blocking electrons is improved. In any case, it is preferable to use an aromatic tertiary amine having a benzidine skeleton and not having a phenylenediamine skeleton for the hole transport layer, and to use an aromatic tertiary amine having a phenylenediamine skeleton for the hole injection layer. Is preferred.

The thickness of the hole injection layer is preferably 1 to 1000 nm, more preferably 1 to 100 nm, and the thickness of the hole transport layer is preferably 1 to 200 nm, more preferably 5 to 100 nm. When only one of these layers is provided, the thickness is preferably 1 to 1000 nm, more preferably 10 to 500 nm.

<Electron Transport and / or Injection Layer> In the present invention, although partially described above, it is preferable to provide an electron transport and / or injection layer. An electron transporting and / or injecting layer (sometimes referred to as an electron injecting and transporting layer) is provided even when an electron transporting layer is provided and the electron injecting and transporting compound in the layer is not used as a host material of the light emitting layer. Is preferred. As the electron injecting and transporting compound in this case, in addition to the phenylanthracene derivative,
Tris (8-quinolinolato) aluminum (AlQ3)
Quinoline derivatives such as organometallic complexes having 8-quinolinol or its derivative as a ligand, oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, etc. be able to.

Particularly, an aluminum complex having a diphenylanthran derivative of the formula (A) and 8-quinolinol or a derivative thereof as a ligand (particularly tris (8-quinolinolato))
Aluminum), the former is preferably used for the electron transport layer on the light emitting layer side, and the latter is preferably used for the electron injection layer on the cathode side. In addition, about the aluminum complex which has 8-quinolinol) or its derivative (s) as a ligand, WO98 / 08
No. 360 and the like.

The thickness of the electron injection layer is preferably 1 to 1000 nm, more preferably 1 to 100 nm, and the thickness of the electron transport layer is 1 to 1000 nm.
500 nm, preferably 1 to 100 nm. When only one of these layers is provided, it is 1 to 1000 nm, and more preferably 1 to 1000 nm.
Preferably, the thickness is about 100 nm.

<Cathode> The cathode material used in the present invention includes alkali metals (Li, Na, K, Rb, Cs
Etc.) are preferably used.
Specifically, lithium fluoride (LiF), lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), sodium fluoride (NaF), sodium chloride (NaCl), sodium bromide (NaBr) ,
Sodium iodide (NaI), rubidium fluoride (Rb
F), of rubidium chloride (RbCl), rubidium bromide (RbBr), rubidium iodide (RbI), cesium fluoride (CsF), cesium chloride (CsCl), cesium bromide (CsBr), cesium iodide (CsI) Examples include halides and oxides such as lithium oxide (Li ₂ O) and sodium oxide (Na ₂ O). Especially Rb, C
Preferred are halides such as s, especially chlorides and iodides.

A material having a lower work function (for example, Li,
Na, K, Mg, Al, Ag, In, or an alloy containing at least one of these materials). The cathode preferably has fine crystal grains, and particularly preferably has an amorphous state. The total thickness of the cathode is 10 to 1000
It is preferable to set it to about nm. The thickness of the lower layer in the configuration using the lower layer is about 0.1 to 1 nm.

The use of an alkali metal halide or oxide as a cathode material is particularly effective in a device having a blue light-emitting layer, and blue light can be stably obtained. Since the energy gap of the host is larger in a blue light emitting system than in a green system, higher efficiency of electron injection and hole injection is required. A conventional cathode such as MgAg has a low electron injection efficiency, and an alkali metal-based material is effective as a high-efficiency alternative material. This is because the work function is small. Further, the work function does not change even if it is in the form of a halide or oxide, or when an electric field is applied, reduction or the like occurs to become a metal. Therefore, it is optimal as an electron injection material that is easy to handle. Also, there is an effect of improving the adhesion between the organic film and the electrode.

The use of a halide or oxide of an alkali metal as a cathode material is particularly effective when an electron injecting / transporting compound or a hole injecting / transporting compound in an electron transporting layer or a hole transporting layer adjacent to a blue light emitting layer is used. It is indispensable in the mode not used as a host material.

The organic layer at the cathode interface may be doped with a metal such as Li.

In addition, the sealing effect is improved by depositing and sputtering Al or a fluorine compound at the end of electrode formation.

When tris (8-quinolinolato) aluminum (AlQ3) or the like is used for the electron injection and / or transport layer and the cathode is formed by sputtering, damage to the electron injection and / or transport layer due to sputtering is prevented. For this purpose, a layer of a naphthacene derivative (described above) such as rubrene can be formed to a thickness of 0.1 to 20 nm between the electron injection and / or transport layer and the cathode.

<Anode> In order to make the organic EL element emit light in the plane.
, At least one electrode is transparent or translucent
And the material of the cathode is limited as mentioned above
So that the transmittance of the emitted light is preferably 80% or more.
It is preferable to determine the material and thickness of the anode. Ingredient
Physically, for example, ITO (tin-doped indium oxide)
), IZO (zinc-doped indium oxide), Sn
O_Two, Ni, Au, Pt, Pd, dopant
It is preferable to use polypyrrole or the like for the anode.
Preferably, ITO and IZO are used. ITO is usually In_TwoO
_ThreeAnd SnO in a stoichiometric composition, but with a high oxygen content.
It may be slightly deviated from this. IZO is typically In_Two
O _ThreeAnd ZnO in a stoichiometric composition, but the oxygen content is
There may be some deviation from this. In_TwoO_ThreeAgainst
SnO_TwoIs 1 to 20% by mass, more preferably 5 to 1% by mass.
2% by mass is preferred. In addition, In in IZO_TwoO_ThreeTo
The mixing ratio of ZnO is usually about 12 to 32% by mass.
is there. The thickness of the anode should be about 10 to 500 nm.
Is preferred. Also, to improve the reliability of the device
It is necessary that the driving voltage be low, but it is preferable.
10-30Ω / □ or 10Ω / □ or less (usually 0.1
-10 / Ω / □).

In a large device such as a display, Al wiring may be used because the resistance of ITO increases.

<Substrate Material> Although there is no particular limitation on the substrate material, a transparent or translucent material such as glass or resin is used to extract emitted light from the substrate side. Alternatively, the color of the emitted light may be controlled by using a color filter film, a fluorescence conversion filter film containing a fluorescent substance, or a dielectric reflection film on the substrate, or coloring the substrate itself.

As the color filter film, a color filter used in a liquid crystal display or the like may be used, but the characteristics of the color filter are adjusted in accordance with the light emitted from the organic EL element to optimize the extraction efficiency and color purity. It should just be.

If a color filter capable of cutting off short-wavelength external light that is absorbed by the EL element material or the fluorescence conversion layer is used, the light resistance of the element and the display contrast are improved.

An optical thin film such as a dielectric multilayer film may be used in place of the color filter.

[0204] The fluorescence conversion filter film absorbs EL light and emits light from the phosphor in the fluorescence conversion film, thereby performing color conversion of the emission color. It is formed from a fluorescent material and a light absorbing material.

As the fluorescent material, basically, a material having a high fluorescence quantum yield may be used, and it is preferable that absorption is strong in an EL emission wavelength region. Actually, laser dyes and the like are suitable, and rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalocyanines, etc.), naphthalimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds Compounds, styryl compounds,
A coumarin compound or the like may be used.

As the binder, basically, a material that does not quench the fluorescence may be selected, and a binder that can be finely patterned by photolithography, printing, or the like is preferable.
Further, a material that does not suffer damage during the deposition of ITO is preferable.

The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but may be omitted when unnecessary. As the light absorbing material, a material that does not quench the fluorescence of the fluorescent material may be selected.

<Emission Color Modulation Using Color Filter>
In the present invention, by combining the above-mentioned organic EL element and a color filter, the emission color of the above-mentioned organic EL element can be modulated, thereby facilitating a multicolor light-emitting organic EL display (multicolor light-emitting device). Can be provided.

When the above-mentioned organic EL element is applied to such a device, the organic EL element includes a light-emitting layer between a pair of electrodes facing each other, and at least one electrode is a transparent electrode. However, since a color filter is used, it is necessary that at least one of the electrodes is a transparent electrode. In order to extract emitted light from the transparent electrode side, the color filter is provided on the transparent electrode side.

[0210] Here, the organic layer refers to a layer containing an organic compound, and the organic compound includes a metal complex having an organic compound as a ligand, an organic metal compound, or the like.

The above device may have a segment type display unit or a dot matrix type display unit, or may have both of these display units. .

The dot matrix type display section has an XY matrix type electrode in which a plurality of electrodes are arranged so as to face and intersect with each other, and an organic layer is sandwiched between the electrodes at the intersection. Thus, a pixel is formed. The color filter is preferably provided on the transparent electrode side of this pixel. In addition, it is preferable that a black matrix is provided in the vicinity of the pixel and near the color filter installation site (usually between the color filters). The black matrix can prevent light leakage between the color filters, thereby improving the visibility of multicolor light emission.

Here, a pixel refers to an area of an image display array which can be excited independently of other areas to emit light.

The above-mentioned plurality of electrodes are usually striped electrodes, and a pair of electrodes are arranged so as to be substantially orthogonal. In manufacturing, a stripe-shaped electrode is often formed by forming one electrode and then forming the other electrode, and a dot matrix type display portion is often formed using an interlayer insulating film. There may be cases where the other stripe-shaped electrode to be formed later is not formed on substantially the same plane, or where one stripe in the same direction does not become a continuous film. I don't mind.

For example, as a method of forming a dot matrix type display section, there is the following method. A predetermined color filter layer is formed on a transparent substrate (glass or the like), and a transparent resin such as an acrylic resin or a polyimide is formed on the transparent electrode forming surface of the color filter layer, preferably to improve the flatness of the surface. An overcoat layer having a thickness of 1 μm to 5 mm is provided. This overcoat layer also functions as a protective layer for the color filter. The overcoat layer is patterned, and a transparent electrode is formed on the patterned overcoat layer. Note that a transparent and electrically insulating inorganic oxide layer may be provided as a passivation layer between the transparent electrode layer and the overcoat layer.

On the surface including the patterned transparent electrode layer,
An interlayer insulating film having a thickness of 10 nm to 100 μm is provided so that the insulating film remains at portions other than the portions where the transparent electrodes are formed. The insulating film can be formed of a resin such as polyimide, acrylic resin, or epoxy resin, in addition to inorganic compounds such as SiO ₂ and SiN _x .

Further, in this case, in addition to the insulating film, there is a method of separating elements by forming a spacer on the insulating film, or forming an overhang body having a width larger than that of the spacer on the spacer. JP-A-9-3307
No. 92).

Thereafter, an organic layer including a light emitting layer in the above-mentioned organic EL device is formed, and a counter electrode is provided so as to intersect the transparent electrode. Can be. It is preferable that the above-mentioned insulating film be left even after the element is formed, and the presence of the above-mentioned insulating film can avoid unnecessary light emission in a portion that cannot be seen from the substrate surface. When a black matrix is used, a black matrix layer may be provided between the color filter layers.

<Color Filter and Black Matrix> i) Color Filter As the color filter used in the present invention, for example, only the following dyes, or those in which the dyes are dissolved or dispersed in a binder resin, include: Can be.

Red (R) dyes: Perylene pigments, lake pigments, azo pigments, quinacridone pigments, anthraquinone pigments, anthracene pigments, isoindoline pigments, isoindolinone pigments and the like, and at least two or more types Mixture of

Green (G) dye: a single product of halogen-substituted phthalocyanine pigment, halogen-substituted copper phthalocyanine pigment, triflemethane-based basic dye, isoindoline pigment, isoindolinone pigment, and at least two or more types Mixture of

Blue (B) dye: copper phthalocyanine pigment, indanthrone pigment, indophenol pigment,
Single products such as cyanine pigments and dioxazine pigments and mixtures of at least two or more

On the other hand, the binder resin is preferably a transparent (50% or more visible light) material. For example, transparent resins (polymers) such as polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, and carboxymethyl cellulose are exemplified.

A photosensitive resin to which a photolithography method can be applied in order to separate and arrange the color filters in a plane is also selected. For example, a photocurable resist material having a reactive vinyl group such as an acrylic acid type, a methacrylic acid type, a polyvinyl cinnamate type, and a ring rubber type may be used. When a printing method is used, a printing ink (medium) using a transparent resin is selected. For example, polyvinyl chloride resin, melamine resin, phenol resin, alkyd resin, epoxy resin, polyurethane resin, polyester resin, maleic acid resin, polyamide resin monomer, oligomer, polymer composition, polymethyl methacrylate, polyacrylate , Polycarbonate,
Transparent resins such as polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethylcellulose, carboxymethylcellulose and the like can be used.

When the color filter is mainly composed of a dye, the film is formed by a vacuum evaporation or sputtering method through a mask of a desired color filter pattern. On the other hand, when the color filter is composed of a dye and a binder resin, a fluorescent dye and the above resin are used. And resist are mixed, dispersed or solubilized, formed into a film by a method such as spin coating, roll coating, or casting, and patterned by a desired color filter pattern by a photolithography method, or a desired color filter by a method such as printing. It is general to pattern by the above-mentioned pattern, and to cure by heat treatment.

The thickness and transmittance of each color filter are preferably as follows. R: film thickness 0.5-2
0 μm (transmittance 50% or more / 610 nm), G: film thickness 0.5 to 20 μm (transmittance 50% or more / 545 nm),
B: film thickness 0.2 to 20 μm (transmittance 50% or more / 460)
nm)

In particular, in the case where the color filter is composed of a dye and a binder resin, the concentration of the dye is such that the color filter can be patterned without any problem and the organic EL is used.
Any range may be used as long as the light emission of the element can be sufficiently transmitted. Although depending on the type of the dye, the color filter film including the binder resin used contains the dye in an amount of 5 to 50% by mass.

Ii) Black matrix Examples of the black matrix used in the present invention include the following metal and metal oxide thin films and black pigments. Specific examples of metal and metal oxide thin films include chromium (Cr), nickel (Ni),
Examples thereof include a thin film of a metal such as copper (Cu) and an oxide thereof. The mixture of the metal and the metal oxide has an optical density of 3.0 or more (film thickness of 10 to 300 nm (100
~ 3000 °)) are preferred.

As specific examples of the black pigment, carbon black, titanium black, aniline black or a pigment of a color filter is mixed and blackened, or the above pigment is dissolved in a binder resin as in the case of the color filter. A dispersed solid state material can be used.

[0230] The metal and metal oxide thin films are deposited on the entire surface of the insulating substrate by sputtering, vapor deposition, CVD, or the like.
After forming a film on at least the entire display portion by a masking method, patterning is performed by a photolithography method to form a black matrix pattern.

When a black dye is used, patterning can be performed in the same manner as in the case of a color filter to form a black matrix.

<Protective Layer (Transparent Flat Film)>
The protective layer (transparent flat film) used as needed protects the color filter (including the black matrix) from being physically damaged and from being deteriorated by external environmental factors (water, oxygen, light). Used. The material is preferably a transparent (50% or more visible light) material.

Specifically, there can be mentioned those having a reactive vinyl group of an acrylate type or a methacrylate type, such as a photocurable resin and / or a thermosetting resin. Also, melamine resin, phenol resin, alkyd resin, epoxy resin, polyurethane resin, polyester resin, maleic acid resin, polyamide resin monomer, oligomer, polymer, polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, polyimide, Transparent resins such as hydroxyethyl cellulose and carboxymethyl cellulose can be mentioned. In order to enhance the light resistance of the color filter and the organic EL element, an ultraviolet absorber may be added to the protective layer.

The protective layer is formed by coating the above-mentioned material in a liquid state by a method such as spin coating, roll coating, or a casting method. The photo-curable resin is cured by heat after irradiation with light, if necessary. The mold is thermally cured as it is after film formation. In the case of a film, an adhesive may be applied and adhered as it is.

There is no particular limitation on the thickness of the protective layer since it hardly affects the viewing angle. However, if the thickness is too large, the light transmittance is affected.
You can choose from a range.

<Transparent and Electrically Insulating Inorganic Oxide Layer> The transparent and electrically insulating inorganic oxide layer used in the present invention may be laminated on a color filter or a protective layer by, for example, vapor deposition, sputtering, or dipping. Can be formed by The transparent and electrically insulating inorganic oxide layer may be a single layer or a multilayer of two or more layers. For example, by using two layers, elution of inorganic ions from a lower inorganic oxide layer (for example, soda-lime glass) can be suppressed by an upper inorganic oxide layer, and the organic EL element can be protected from the eluted ions. it can.

As the material, silicon oxide (Si
O ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), yttrium oxide (Y ₂ O ₃ ), germanium oxide (GeO ₂ ), zinc oxide (ZnO), magnesium oxide (MgO), calcium oxide (CaO), boric acid (B ₂ O ₃ ), strontium oxide (SrO), barium oxide (BaO), lead oxide (PbO), zirconia (Z
rO ₂ ), sodium oxide (Na ₂ O), lithium oxide (Li ₂ O), potassium oxide (K ₂ O), and the like. Silicon oxide, aluminum oxide, and titanium oxide are layers (films) thereof. Is preferred because it has high transparency and its film forming temperature is relatively low (250 ° C. or less), and hardly deteriorates the color filter or the protective layer.

Further, as the transparent and electrically insulating inorganic oxide layer, a glass plate or one or more compounds selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide and the like can be used as a transparent insulating inorganic oxide layer. In the case of a glass plate formed on at least one of the upper surface and the lower surface of the glass plate, a low-temperature operation (150 ° C. or less) of merely bonding the color filter or the protective layer is possible. It is more preferable because it does not deteriorate at all. In addition, the glass plate has a great effect of blocking deteriorating gases such as water vapor, oxygen, and monomers.

Table 1 or Table 2 shows the composition of the glass plate.
Can be mentioned. In particular, soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass and the like can be mentioned. In addition,
Here, the electrically insulating inorganic oxide layer may have any composition as long as it mainly contains an inorganic oxide, and may contain a nitride (for example, Si ₃ N ₄ ).

The thickness of the transparent and electrically insulating inorganic oxide layer is not particularly limited as long as it does not hinder the light emission of the organic EL element. In the present invention, the thickness is 0.01 μm to 200 μm.
The following is preferred. A glass plate, or a glass plate obtained by forming at least one of the upper and lower surfaces of a transparent insulating glass plate with one or more compounds selected from the group consisting of silicon oxide, aluminum oxide, and titanium oxide, , 1μm or more and 200μ due to the accuracy and strength of sheet glass
m or less is preferable. Here, when the thickness of the transparent and electrically insulating inorganic oxide layer is reduced, it approaches a single-layer film of the inorganic oxide particles, and water vapor, oxygen, monomer, or the like generated from an organic substance of the color filter or the protective layer is used. As it becomes difficult to block the deteriorating gas and the film thickness increases, the emission of the organic EL element leaks from the gap with the color filter, depending on the definition of the color filter. In some cases, the practicability of the multicolor light emitting device may be reduced.

[0241]

[Table 1]

[0242]

[Table 2]

<Method for Manufacturing Organic EL Element> Next, a method for manufacturing the organic EL element of the present invention will be described. The anode is preferably formed by a vapor phase growth method such as an evaporation method or a sputtering method.

The cathode can be formed by a vapor deposition method or a sputtering method. However, in consideration of the fact that the cathode is formed on the organic layer, a vapor deposition method that causes less damage to the organic layer is preferable.

In forming an organic layer such as a light emitting layer, it is preferable to use a vacuum evaporation method since a uniform thin film can be formed. When the vacuum evaporation method is used, the amorphous state or the crystal grain size is 0.1 μm or less (the lower limit is usually 0.001 μm or less).
It is about μm. ) Is obtained. If the crystal grain size exceeds 0.1 μm, the light emission becomes non-uniform, the driving voltage of the device must be increased, and the charge injection efficiency is significantly reduced.

The conditions for vacuum deposition are not particularly limited.
0 ^-3 and a degree of vacuum below Pa, the deposition rate 0.1 to 1 nm / se
It is preferably about c. Further, it is preferable to form each layer continuously in a vacuum. If they are formed continuously in a vacuum, impurities can be prevented from adsorbing at the interface between the layers, so that high characteristics can be obtained. Further, the driving voltage of the element can be reduced, and the generation and growth of dark spots can be suppressed.

In the case where a plurality of compounds are contained in one layer such as a mixed layer in the case where a vacuum evaporation method is used to form each of these layers, each boat containing the compounds is individually controlled in temperature and evaporated from a different evaporation source. Co-evaporation is preferred, but when the vapor pressures (evaporation temperatures) are similar or very close,
It is also possible to mix them in the same evaporation board in advance and perform evaporation.

In addition, a solution coating method (spin coating, dip, cast, etc.), a Langmuir-Blodgett (LB) method, or the like can also be used. In the solution coating method, each compound may be dispersed in a matrix material (resin binder) such as a polymer. The method for forming the color filter is as described above.

The organic EL device of the present invention is generally used as a DC-driven EL device, but can be driven by AC or pulse. The applied voltage is usually 2 to 10
About V and lower than the conventional one.

[0250]

EXAMPLES Examples of the present invention will be described below with reference examples, and the present invention will be described in more detail. The structural formula of the compound used in the example is shown.

[0251]

Embedded image

[0252]

Embedded image

Example 1 An ITO transparent electrode (anode) was formed to a thickness of 100 nm on a glass substrate by a sputtering method.

Then, the glass substrate on which the ITO transparent electrode was formed was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol. The substrate was pulled out of boiling ethanol, dried, washed with UV / O ₃ , fixed to a substrate holder of a vacuum evaporation apparatus, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa or less.

Next, N, N'-diphenyl-N, N'-bis [N-
[Phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34) was deposited at a deposition rate of 0.2 nm / sec to a thickness of 20 nm to form a hole injection layer.

N, N, N ', N'-tetrakis- (3-biphenyl-1-
Yl) benzidine (tetraarylbenzidine derivative (N
oI-1)) was deposited at a deposition rate of 0.2 nm / sec to a thickness of 20 nm to form a hole transport layer.

Further, tetraarylbenzidine derivatives
(No. I-1) and 10,10′-bis [2-biphenylyl] -9,9′-bianthril (phenylanthracene derivative (No. 1-1)) in a volume ratio of 1: 3. And naphthacene derivatives (No.
20) is co-deposited to a thickness of 30 nm so as to contain 3.0 vol%,
This was a mixed layer type first light emitting layer. The deposition rate at this time is 0.05 nm / sec, 0.15 nm / sec, 0.00
6 nm / sec.

Further, a tetraarylbenzidine derivative (N
oI-1) and a phenylanthracene derivative (No. 1-1) in a thickness of 50 nm such that the volume ratio is 1: 3 and the styrylamine derivative (S-9) is contained at 3.0 vol%. Co-evaporation was performed to obtain a mixed layer type second blue light emitting layer. The deposition rate at this time is 0.05 nm / sec and 0.15 nm / se in order.
c, 0.006 nm / sec.

Next, a phenylanthracene derivative (No. 1-1) was deposited at a deposition rate of 0.05 nm / se while maintaining the reduced pressure.
The film was deposited by c to a thickness of 20 nm to form an electron transport layer. Also,
Tris (8-quinolinolato) aluminum (AlQ3)
Was deposited at a deposition rate of 0.2 nm / sec to a thickness of 10 nm to form an electron injection layer.

Further, while maintaining the reduced pressure, CsI was deposited at a deposition rate of 0.05 nm / sec to a thickness of 0.2 nm, and MgAg (mass ratio 10: 1) was deposited thereon at a deposition rate of 0.2 nm.
The cathode was formed by vapor deposition to a thickness of 200 nm / sec, and 100 nm of Al was deposited as a protective layer to obtain an organic EL device.

As shown in FIG. 1, such an organic EL device has an anode 2 on a substrate 1, a hole injection layer 3, a hole transport layer 4, and a first light emitting layer of a mixed layer type on the anode 2. A layer 5, a mixed layer type second light-emitting layer 6, an electron transport layer 7, and an electron injection layer 8 in this order, and further thereon, a cathode lower layer 9 formed of an alkali metal compound and a work function having a small work function. It has a cathode composed of a cathode upper layer 10 made of metal, and emits emitted light from the substrate 1 side.

When this organic EL device was driven at a constant current density of 10 mA / cm ² , the initial luminance was 1100 cd / m ² and the driving voltage was 6.0 V. The emission color was white. The half-life of the luminance is 9000 cd / cm ² for the initial luminance at a constant current drive of 100 mA / cm ² and 600 hours at a drive voltage of 9.9 V, and 1100 cd / c for a constant current drive of 10 mA / cm ^2.
It was 50,000 hours at m ² and a driving voltage of 6.0 V.

<Embodiment 2> In the device of Embodiment 1,
An element was obtained in the same manner except that N, N′-di (1-naphthyl) -N, N′-diphenylbenzidine (NPB) was used instead of (tetraarylbenzidine derivative (No. I-1)). When the characteristics were evaluated in the same manner, white light emission was obtained, and the initial luminance was 9000 cd / c at a constant current drive of 100 mA / cm ^2.
m ² , driving voltage 9.8 V, luminance half-life 500 hours, and initial luminance 1100 cd / m at constant current driving of 10 mA / cm ^2.
m ² , a driving voltage of 5.5 V, and a luminance half life of 35,000 hours.

Example 3 An element was obtained in the same manner as in Example 1, except that the mixed layer type first light emitting layer was not provided, and the characteristics were evaluated in the same manner. Obtained at a constant current drive of 100 mA / cm ² , an initial luminance of 8500 cd / m ² , a drive voltage of 7.8 V and a luminance half-life of 500
Time, 10mA / cm ² constant current drive, initial luminance 900
The cd / m ² , the driving voltage was 6.0 V, and the luminance half life was 30,000 hours.

The emission spectra of the organic EL devices of Examples 1 and 3 are shown in FIG. The organic EL element of Example 1 emits white light, and the organic EL element of Example 3 emits blue light.

<Reference Example 1> An element was manufactured in the same manner as in Example 1. However, without using cesium iodide used as an electron injection electrode, MgAg was vapor-deposited directly on AlQ3 to form an electrode.

The luminance at 10 mA / cm ² was 400 cd / m ² , and orange light emission with a driving voltage of 9.0 V was obtained. When the emission spectrum was measured, 90% or more of the naphthacene derivative (No.
20).

When the luminescence lifetime was measured, it was found that 100
The luminance at a constant current drive of mA / cm ² was 4000 cd / m ² , and the luminance half time was 4 hours. In particular, the intensity of blue light emission was significantly reduced.

<Reference Example 2> An element was manufactured in the same manner as in Example 1. However, the light-emitting layer is composed of (tetraarylbenzidine derivative (No.I-1)) and phenylanthracene derivative (No.1-1)
Phenylanthracene derivative (No. 1-
As a sole host of 1), a naphthacene derivative (No. 20) and a styrylamine derivative (S-9) were similarly doped.

The luminance at a constant current drive of 10 mA / cm ² is 900
At cd / m ² , orange light emission with a driving voltage of 7.5 V was emitted. When the emission spectrum was measured, 75% or more was emitted from the naphthacene derivative (No. 20).

When the emission life was measured, it was 100
The luminance at a constant current drive of mA / cm ² was 9000 cd / m ² , and the luminance half time was 100 hours. In particular, the intensity of blue light emission was significantly reduced.

Example 4 [Preparation of Organic EL Display] A 7059 substrate (trade name, manufactured by Corning Incorporated) as a glass substrate was scrubbed with a neutral detergent.

In order to form a color filter on this substrate, a coating / patterning step of a pigment dispersion type color filter, which is the most common method of colorizing a liquid crystal display, was performed. Red, green, blue each 1.0-1.5μm
The coating conditions were determined so as to obtain a filter film thickness of, and desired patterning was performed. 1 color filter material for red
Spin coating was performed at 000 rpm for about 5 seconds, and prebaked at 100 ° C. for 3 minutes. Align the photomask with the exposure machine,
After irradiation with 20 mW of ultraviolet light for 30 seconds, development was performed with an aqueous solution of TMAH (tetra methyl ammonium hydride) having a concentration of about 0.1% by mass. The development time was about 1 minute. 220 ° C so as not to dissolve in the color filter liquid of another color to be applied after this.
For 1 hour to obtain a red color filter. For other colors, although the material (pigment) is different and the detailed forming conditions are different, substantially the same steps were sequentially performed to form a color filter.

Next, in order to improve the flatness of the surface on which the ITO film is to be formed, an overcoat material of an acrylic resin is applied, a desired patterning is performed, and curing is performed at about 220 ° C. for 1 hour. Layer obtained. The thickness of the overcoat layer was about 3 μm.

Then, about 100 nm of ITO was formed as a transparent conductive film by sputtering, and a resist pattern was formed by photolithography, followed by etching with dilute hydrochloric acid and stripping the resist to obtain an ITO pattern.

[0276] The SiO ₂ was formed by sputtering as an insulating film patterned on ITO, and patterned so as SiO ₂ remains other than the portion further emission is visible from the glass substrate side, about 0 to SiO ₂ insulating film .. 1 μm thick.

Next, in the same manner as in Example 1, an organic layer, a cathode and a protective layer of the organic EL device were formed, and white, green,
An organic EL display having each blue dot was produced. The pixel size was 2 mm x 2 mm, and the number of pixels was 1 dot for each color.

This was driven at a constant current of 100 mA / cm ² to confirm the light emission of each color. The luminance and CIE chromaticity of each color were as follows.

[0279]

<Example 5> [Simple matrix type organic E]
Production of L Color Display] A substrate prepared in the same manner as in Example 4 was fixed to a substrate holder of a sputtering apparatus, Al was sputtered to a thickness of about 1.5 μm, and TiN was continuously formed to a thickness of about 30 nm. A multilayer film of Al and TiN was formed by sputtering. Since Al and TiN are continuously formed without breaking the vacuum, formation of a natural oxide film on the surface of the Al layer is prevented, and good contact between Al and TiN is obtained. This laminated film was patterned by photolithography to form a low-resistance wiring.

A color filter and an overcoat layer were formed in the same manner as in Example 4. The pattern was made to expose the surface of the TiN layer.

Then, an ITO pattern as a transparent conductive film was formed in the same manner as in Example 4. This is ITO
And the previously formed low resistance Al wiring are connected to form a column line.

[0283] The SiO ₂ was formed by sputtering as an insulating film patterned on ITO, further emission is patterned so as SiO ₂ remains other than the portion visible from the glass substrate side, about 0 to SiO ₂ insulating film. It was formed to a thickness of 1 μm. As a result, it is possible to avoid unnecessary light emission in a part that cannot be seen from the glass substrate side. Further, since this portion becomes a hole or a groove, the organic EL layer deposited on the inclined portion becomes thinner, which is likely to cause a current leak, but this can be prevented.

Next, a polyimide film whose concentration was adjusted to 15% by mass was spin-coated so as to have a film thickness of 2 μm, and was prebaked at 145 ° C. for 1 hour to form an intermediate spacer film. Then, apply a positive resist,
Exposure and development to form the desired photo pattern,
A cap-shaped photosensitive resin body was formed. The intermediate spacer film of polyimide, which is exposed during the development of the positive resist, is subsequently removed from the positive resist by the developer to form a final spacer shape. As a result, an element isolation structure was formed.

Next, an organic layer, a cathode and a protective film of the organic EL device were formed in the same manner as in Example 1, and the size of one pixel was 330 μm × 110 μm and the number of pixels was 320 × 240
A simple matrix type color display of × RGB dots was produced.

When this was driven line-sequentially, color light emission was obtained with the same CIE chromaticity as in Example 4.

Example 6 A display was manufactured in the same manner as in Example 4, except that the black matrix was provided between the color filters after the alignment.
When driven in the same manner, sharper emission light was obtained than in Example 4. As the black matrix, a general pigment dispersion type was used.

Example 7 A display was fabricated in the same manner as in Example 4 except that an overcoat layer of an acrylic resin was provided, and then a protective film having a thickness of about 60 nm was further provided thereon with an SiO ₂ film. Produced. When driven in the same manner, the same result as in Example 4 was obtained. It was also found that the durability of the element was further improved.

[0289]

According to the present invention, blue light can be efficiently obtained. Further, it is possible to cope with multicolor light emission including blue light emission, and obtain an organic EL element with high luminance and long life. Furthermore, by utilizing the excellent characteristics of the organic EL element, a multicolor light emitting organic display can be manufactured by combination with a color filter.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of an organic EL element in an example.

FIG. 2 is a graph showing an emission spectrum of an organic EL device in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 First light emitting layer 6 Second light emitting layer 7 Electron transport layer 8 Electron injection layer 9 Cathode lower layer 10 Cathode upper layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/22 H05B 33/22 C 33/26 33/26 Z (72) Inventor Tetsuji Fujita Chuo-ku, Tokyo (72) Inventor Kenji Nakatani 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDC Corporation

Claims (27)

[Claims] 1. A light emitting device comprising: a light emitting layer; a hole transporting layer and / or an electron transporting layer adjacent to the light emitting layer, wherein the light emitting layer is composed of one or more layers including a blue light emitting layer; An organic EL device in which a layer contains a hole injection / transport compound and / or an electron injection / transport compound in the hole transport layer and / or the electron transport layer as a host compound. 2. The organic EL device according to claim 1, wherein the host compound is a compound that emits blue light. 3. The organic EL device according to claim 2, wherein the host compound is selected from a phenylanthracene derivative. 4. The organic EL device according to claim 1, which contains a dopant and emits blue light by the dopant. 5. It has a hole transport layer and an electron transport layer,
The organic EL device according to claim 1, wherein the blue light emitting layer is a mixed layer of a hole injecting and transporting compound and an electron injecting and transporting compound in the hole transporting layer and the electron transporting layer. 6. The organic EL device according to claim 5, wherein the blue light emitting layer is a mixed layer of a phenylanthracene derivative and an aromatic tertiary amine. 7. The organic EL device according to claim 5, wherein the concentration distribution of the hole injecting and transporting compound and the electron injecting and transporting compound in the mixed layer is uniform. 8. The hole injection / transport compound and the electron injection / transport compound in the mixed layer have a concentration distribution in the thickness direction.
7. The organic EL device according to claim 5, wherein the concentration of the hole injecting and transporting compound is high on the hole transporting layer side, and the concentration of the electron injecting and transporting compound is high on the electron transporting layer side. 9. The organic EL device according to claim 5, which is a mixed layer further doped with a dopant. 10. The mixed layer emits blue light as a whole.
9. The organic EL device according to any one of 9. 11. The constituent material of the cathode provided on the electron transport layer side contains at least one compound selected from halides and oxides of alkali metals.
Any one of the organic EL devices. 12. The organic EL device according to claim 11, wherein the constituent material of the cathode contains at least one compound selected from halides of Rb and Cs. 13. A cathode, one or more light-emitting layers including a blue light-emitting layer, a hole transport layer and / or an injection layer, and an anode, wherein the constituent material of the cathode is an alkali metal. An organic EL device containing at least one compound selected from halides and oxides. 14. The organic EL device according to claim 13, wherein the blue light emitting layer contains a phenylanthracene derivative as a compound emitting blue light. 15. The organic EL device according to claim 13, wherein the hole transporting and / or injecting layer contains an aromatic tertiary amine. 16. The organic EL device according to claim 15, wherein the aromatic tertiary amine is selected from the compounds represented by the formulas (1) and (2). Embedded image [In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ are
Each represents an aryl group, an alkyl group, an alkoxy group, an aryloxy group or a halogen group; r ₁ , r ₂ , r ₃ and r ₄ are each an integer of 0 to 5, r ₁ , r ₂ , r ₃ and When r ₄ is an integer of 2 or more, adjacent R _{1 s} , R _{2 s} , R _{3 s,} and R _{4 s}
And each other may be bonded to each other to form a ring.
R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen group, and r ₅ and r ₆ are each an integer of 0 to 4. ] [In the formula (2), φ represents a phenylene group, and R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ are an alkyl group, an aryl group, a diarylaminoaryl group, respectively. Wherein at least one of R _{01 to} R ₀₄ is a diarylaminoaryl group, or (a-1) to (a
-3). r ₀₁ , r ₀₂ , r ₀₃ and r ₀₄
Is an integer of 0 to 5, and r ₀₁ + r ₀₂ + r ₀₃ + r ₀₄ is an integer of 1 or more. r ₀₁ ,
When r ₀₂ , r ₀₃ and r ₀₄ are each an integer of 2 or more, adjacent R _{01 s} , R _{02 s} , R _{03 s} and R _{03 s
04} may be mutually bonded to form a ring. ] 17. A hole injection layer and a hole transport layer, wherein the hole injection layer on the anode side contains the compound represented by the formula (2), and the hole transport layer on the light emitting layer side is represented by the formula (1). The organic EL device according to claim 15, comprising a compound to be prepared. 18. The light-emitting device according to claim 1, further comprising at least one light-emitting layer having a different emission wavelength from the blue light-emitting layer.
17. The organic EL device according to any one of items 17 to 17. 19. The organic E compound according to claim 18, wherein at least one light emitting layer having a different emission wavelength from the blue light emitting layer is a mixed layer of a hole injection transport compound and an electron injection transport compound.
L element. 20. The organic EL device according to claim 19, which is a mixed layer further doped with a dopant. 21. A light-emitting device comprising two light-emitting layers.
0 organic EL element. 22. The light-emitting device according to claim 18, which has three light-emitting layers.
0 organic EL element. 23. The organic EL device according to claim 21, which emits white light. 24. The organic EL device according to claim 1, wherein a light emission color is modulated using a color filter in combination with the color filter. 25. A pair of electrodes which are opposed to each other and at least one of which is transparent, an organic layer including the light emitting layer is sandwiched between the pair of electrodes, and the transparent electrode side of the pair of electrodes is The organic EL device according to claim 24, further comprising a color filter. 26. A XY matrix type electrode comprising a plurality of electrodes, each of which is composed of a plurality of electrodes, intersects each other, and is arranged at a position facing each other, at least one of which is a transparent XY matrix type electrode,
25. The organic EL device according to claim 24, wherein an organic layer including the light emitting layer is interposed between the intersecting electrodes, and the intersection forms a pixel, and the color filter is provided on a transparent electrode side of the pixel. . 27. The organic EL device according to claim 26, wherein a black matrix is provided in a peripheral portion of the pixel and near a portion where the color filter is provided.