JP2000268971A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent(EL) element of high efficiency, long life and low cost having merits of organic and inorganic materials. SOLUTION: This organic EL element has a hole injecting electrode 2, a negative electrode 7 and an organic layer having at least a luminous layer 5 between these electrodes. The element also has a high-resistant inorganic electron injecting transport layer 6 having a communicating path for blocking holes and transferring electrons between the luminous layer 5 and the negative electrode 7 and a high-resistant inorganic hole transport layer 4 having a communicating path for blocking electrons and transferring holes between the luminous layer 5 and the hole injecting electrode 2. An organic hole injecting layer is disposed between the high-resistant inorganic hole transport layer 4 and the hole injecting electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL (electroluminescence) device, and more particularly, to an inorganic / organic junction structure used in a device that emits light by applying an electric field to a thin film of an organic compound.

[0002]

2. Description of the Related Art Organic EL devices can be formed on glass in a large area, and are being researched and developed for displays and the like. In general, an organic EL element is formed by forming a transparent electrode such as ITO on a glass substrate, and laminating an organic amine-based hole transport layer and an organic light emitting layer made of, for example, an Alq3 material which exhibits electron conductivity and emits strong light. Further, an electrode having a small work function, such as MgAg, is formed and used as a basic element.

[0003] The element structure reported so far has a structure in which one or more organic compound layers are interposed between a hole injection electrode and an electron injection electrode. There is a two-layer structure or a three-layer structure.

[0004] Examples of the two-layer structure include a structure in which a hole transport layer and a light emitting layer are formed between a hole injection electrode and an electron injection electrode, or a light emitting layer and an electron transport layer between a hole injection electrode and an electron injection electrode. Is formed. As an example of the three-layer structure, there is a structure in which a hole transport layer, a light emitting layer, and an electron transport layer are formed between a hole injection electrode and an electron injection electrode. Also, a single-layer structure in which a single layer has all the functions has been reported for polymers and mixed systems.

FIGS. 2 and 3 show a typical structure of an organic EL device.

In FIG. 2, a hole transport layer 14 and a light emitting layer 15 which are organic compounds are formed between a hole injection electrode 12 and an electron injection electrode 13 provided on a substrate 11. In this case, the light emitting layer 15 also functions as an electron transport layer.

In FIG. 3, a hole transport layer 14, an emission layer 15, and an electron transport layer 16, which are organic compounds, are formed between a hole injection electrode 12 and an electron injection electrode 13 provided on a substrate 11.

In these organic EL devices, reliability is a common problem. That is, the organic EL element has a hole injection electrode and an electron injection electrode in principle, and requires an organic layer for injecting and transporting holes and electrons efficiently between these electrodes. However, these materials are susceptible to damage at the time of manufacturing, and have a problem in affinity with electrodes. In addition, degradation of the organic thin film LED
There is a problem that it is significantly larger than LD.

An electroluminescent (EL) element emits light under the influence of an electric field. The operation of the semiconductor layer constituting such an EL is performed through radiative coupling of electron-hole pairs injected into the semiconductor from a pair of electrodes. One example is G
There are light emitting diodes based on aP and similar III-V semiconductors. Although effective and widely used, these devices are extremely difficult to use in large area displays due to their very small size. Several alternative materials are known that can be used for large area displays. And ZnS is the most useful among such inorganic semiconductors. However, this system has practical drawbacks that cannot be ignored, first of all, its reliability is poor. One example of a mechanism related to ZnS is considered to be that, under a strong electric field, one kind of carrier is accelerated through the semiconductor, thereby causing local excitation of the semiconductor which is alleviated by radiation emission.

[0010] In order to solve such a problem, there has been proposed a method utilizing the respective merits of the organic material and the inorganic semiconductor material. That is, an organic / inorganic semiconductor junction in which the organic hole transport layer is replaced with an inorganic p-type semiconductor. Such a study has been discussed in Japanese Patent No. 2636341, Japanese Patent Application Laid-Open No. 2-139983, Japanese Patent Application Laid-Open No. 2-207488, and Japanese Patent Application Laid-Open No. 6-119773. Organic EL of conventional element
It was extremely difficult to obtain a characteristic exceeding.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to combine the advantages of organic materials and inorganic materials with high efficiency,
An object of the present invention is to provide a long-life, low-cost organic EL element.

[0012]

Means for Solving the Problems That is, the above object is as follows.
This is achieved by the following configuration. (1) a hole injection electrode, a negative electrode, and an organic layer having at least a light emitting layer between these electrodes, between the light emitting layer and the negative electrode for blocking holes and transporting electrons; A high-resistance inorganic hole transport layer having a high-resistance inorganic electron injection / transport layer having a conduction path, and having a conduction path for blocking electrons and transporting holes between the light emitting layer and the hole injection electrode. And an organic EL device having an organic hole injection layer between the high-resistance inorganic hole transport layer and the hole injection electrode. (2) The high-resistance inorganic hole transport layer has a resistivity of 1
The organic EL device according to the above (1), which has a size of 1 to 10 ¹¹ Ω · cm. (3) The high-resistance inorganic hole transport layer according to the above (1) or (2), wherein the high-resistance inorganic hole transport layer contains one or more of a metal and / or an oxide, carbide, nitride, silicide, and boride of the metal. Organic EL element. (4) The high-resistance inorganic hole transport layer is mainly composed of an oxide of silicon and / or germanium. When this main component is represented by (Si _1-x Ge _x ) O _y , 0 ≦ x ≦ 1, 1.7 ≦ y ≦ 2.2, and a metal having a work function of 4.5 eV or more and / or
Or (1) to (1) containing any one or more of metal oxides, carbides, nitrides, silicides, and borides
The organic EL device according to any one of (3). (5) The metal is Au, Cu, Fe, Ni, Ru,
Sn, Cr, Ir, Nb, Pt, W, Mo, Ta, Pd
And the organic EL device according to the above (4), which is at least one of Co and Co. (6) The content of the metal and / or oxide, carbide, nitride, silicide and boride of the metal is 0.2
The organic EL according to the above (4) or (5), wherein
element. (7) The thickness of the high-resistance inorganic hole transporting layer is set to 0.1.
The organic EL device according to any one of the above (1) to (6), which has a thickness of 2 to 100 nm. (8) The high-resistance inorganic electron injecting layer has a work function of 4 eV or less as a first component, and at least one oxide selected from an alkali metal element, an alkaline earth metal element, and a lanthanoid element. (1) containing, as a second component, at least one metal having a work function of 3 to 5 eV.
The organic EL device according to any one of (1) to (7). (9) The second component is Zn, Sn, V, Ru, Sm
And the organic EL device according to the above (8), which is at least one selected from In and In. (10) The alkali metal element is Li, Na, K,
One or more of Rb, Cs and Fr, and the alkaline earth metal element is one or more of Mg, Ca and Sr;
The lanthanoid element is selected from La and Ce1
The organic EL device according to the above (8) or (9), comprising at least one species. (11) The organic EL device according to any one of (1) to (10), wherein the high-resistance inorganic electron injection layer has a resistivity of 1 to 1 × 10 ¹¹ Ω · cm. (12) The organic EL device according to any one of (8) to (11), wherein the high-resistance inorganic electron injection layer contains the second component in an amount of 0.2 to 40 mol% based on all components. (13) The film thickness of the high-resistance inorganic electron injection layer is set to 0.1.
The organic EL device according to any one of the above (1) to (12), which has a thickness of 3 to 30 nm.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The organic EL device of the present invention has a hole injection electrode, a negative electrode, and an organic layer having at least a light emitting layer between these electrodes. A high-resistance inorganic electron injecting and transporting layer having a conduction path for blocking holes and transporting electrons, and for blocking electrons and transporting holes between the light emitting layer and the hole injecting electrode. And an organic hole injection layer between the high resistance inorganic hole transport layer and the hole injection electrode.

The negative electrode (electron injecting electrode) does not need to be particularly limited because it does not need to have a low work function and an electron injecting property in combination with the following high resistance inorganic electron injecting layer. Ordinary metals can be used. Among them, Al, Ag, In, T in terms of conductivity and ease of handling.
One, two or more metal elements selected from i, Cu, Au, Mo, W, Pt, Pd and Ni, particularly Al and Ag are preferable.

The thickness of the cathode electrode thin film may be a certain thickness or more that can provide electrons to the high-resistance inorganic electron injecting and transporting layer, and may be 50 nm or more, preferably 100 nm or more. Although the upper limit is not particularly limited, the film thickness may be generally about 50 to 500 nm.

The following may be used as the electron injection electrode, if necessary. For example, K, Li, Na, M
g, La, Ce, Ca, Sr, Ba, Sn, Zn, Zr
Or a two-component or three-component alloy system containing them for improving stability, for example, Ag.Mg.
(Ag: 0.1 to 50 at%), Al.Li (Li: 0.
01 to 14 at%), In.Mg (Mg: 50 to 80 at%)
%), Al.Ca (Ca: 0.01 to 20 at%), and the like.

The thickness of the electron-injection electrode thin film may be a certain thickness or more capable of sufficiently injecting electrons.
The thickness is preferably 0.5 nm or more, particularly 1 nm or more.
The upper limit is not particularly limited.
It may be about 500 nm. On the electron injection electrode,
Further, an auxiliary electrode (protection electrode) may be provided.

The thickness of the auxiliary electrode may be a certain thickness or more, preferably 50 nm or more, more preferably 100 nm or more, in order to secure electron injection efficiency and prevent entry of moisture, oxygen or an organic solvent. A range from 100 to 500 nm is preferred. If the auxiliary electrode layer is too thin, the effect cannot be obtained, and the step coverage of the auxiliary electrode layer is reduced, and the connection with the terminal electrode is not sufficient. On the other hand, if the auxiliary electrode layer is too thick, the stress of the auxiliary electrode layer increases, which causes adverse effects such as an increase in the growth rate of dark spots.

As the auxiliary electrode, an optimum material may be selected and used depending on the material of the electron injection electrode to be combined. For example, if importance is placed on ensuring electron injection efficiency, a low-resistance metal such as Al may be used, and if importance is placed on sealing properties, a metal compound such as TiN may be used.

The total thickness of the electron injection electrode and the auxiliary electrode is not particularly limited, but is usually 50 to 500 nm.
It should be about the degree.

The material for the hole injection electrode is preferably a material capable of efficiently injecting holes into the hole injection layer or the like, and is preferably a material having a work function of 4.5 eV to 5.5 eV. Specifically, tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), indium oxide (In
₂ O ₃ ), tin oxide (SnO ₂ ) and zinc oxide (Zn
O) having a main composition of either of them is preferable. These oxides may deviate somewhat from their stoichiometric composition. The mixing ratio of SnO ₂ to In ₂ O ₃ is 1 to 20.
wt%, more preferably 5 to 12 wt%. Also, IZO
The mixing ratio of ZnO to In ₂ O ₃ is usually 12
About 32% by weight.

The hole injection electrode may contain silicon oxide (SiO ₂ ) to adjust the work function.
The content of silicon oxide (SiO ₂ ) is preferably about 0.5 to 10% by mol ratio of SiO _{2 to} ITO. S
The inclusion of iO ₂ increases the work function of ITO.

The electrode on the light extraction side has an emission wavelength band,
The light transmittance is usually 400 to 700 nm, particularly preferably 50% or more, more preferably 80% or more, and particularly preferably 90% or more for each emitted light. If the transmittance is too low, the light emission itself from the light emitting layer is attenuated, and it becomes difficult to obtain the luminance required for the light emitting element.

The thickness of the electrode is 50-500 nm, especially 50
The range of -300 nm is preferred. The upper limit is not particularly limited. However, if the thickness is too large, there is a fear that the transmittance is reduced or the layer is peeled off. If the thickness is too small, a sufficient effect cannot be obtained, and there is a problem in film strength at the time of production and the like.

The organic EL device of the present invention comprises:
A high-resistance inorganic electron injecting and transporting layer is provided between the cathode and the negative electrode.

As described above, by arranging the inorganic electron injecting and transporting layer having an electron conduction path and capable of blocking holes between the organic layer and the electron injecting electrode (cathode), electrons can be efficiently injected into the light emitting layer. As a result, the luminous efficiency can be improved and the driving voltage can be reduced.

Preferably, the second component of the high-resistance inorganic electron injecting and transporting layer is contained in an amount of 0.2 to 40 mol% based on all components.
By forming the conductive path by containing the compound, electrons can be efficiently injected from the negative electrode (electron injection electrode) to the organic layer on the light emitting layer side. In addition, the movement of holes from the organic layer to the negative electrode side can be suppressed, and the recombination of holes and electrons in the light emitting layer can be performed efficiently. Further, an organic EL device having both the advantages of the inorganic material and the advantages of the organic material can be obtained. The organic EL device of the present invention can obtain a luminance equal to or higher than that of a device having a conventional organic electron injection layer, and
Because of its high heat resistance and weather resistance, it has a longer lifespan than conventional ones and less occurrence of leaks and dark spots. Further, not only relatively expensive organic substances but also inorganic materials which are inexpensive, easily available and easily manufactured can be used to reduce manufacturing costs.

The resistivity of the high-resistance inorganic electron injecting and transporting layer is preferably 1 to 1 × 10 ¹¹ Ω · cm, particularly 1 × 10 ³ Ω · cm.
１1 × 10 ⁸ Ω · cm. By setting the resistivity of the high-resistance inorganic electron injection / transport layer to the above range, the electron injection efficiency can be dramatically improved while maintaining high electron blocking properties. The resistivity of the high-resistance inorganic electron injecting and transporting layer can also be determined from the sheet resistance and the film thickness.

The high-resistance inorganic electron injecting and transporting layer preferably has a work function of 4 eV or less as a first component, more preferably 1 eV or less.
４4 eV, preferably Li, Na, K, Rb, C
one or more alkali metal elements selected from s and Fr, or one or more alkaline earth metal elements preferably selected from Mg, Ca and Sr, or 1 preferably selected from La and Ce Contains oxides of any one or more of the lanthanoid elements. Of these, lithium oxide, magnesium oxide, calcium oxide, and cerium oxide are particularly preferred. When these are mixed and used, the mixing ratio is arbitrary. Lithium oxide is 50 mol% in terms of Li ₂ O in these mixtures.
It is preferable that it is contained above.

The high-resistance inorganic electron injecting and transporting layer further contains, as the second component, preferably at least one element selected from Zn, Sn, V, Ru, Sm and In. In this case, the content of the second component is preferably 0.2 to 40.
mol%, more preferably 1 to 20 mol%. If the content is less than this, the electron injection function is reduced, and if the content exceeds this, the hole blocking function is reduced. When two or more kinds are used in combination, the total content is preferably in the above range. The second component may be in a metal element state or an oxide state.

By including the conductive (low resistance) second component in the high resistance first component, the conductive material is present in the insulating material in the form of islands. It is believed that a hopping path is formed.

The oxide of the first component usually has a stoichiometric composition, but may deviate slightly from this to have a non-stoichiometric composition. The second component also usually exists as an oxide, and the same applies to this oxide.

In the high-resistance inorganic electron injection / transport layer,
As impurities, H, Ne, Ar used for a sputtering gas,
Kr, Xe, etc. may be contained in a total of 5 at% or less.

The average value of the whole high-resistance inorganic electron injecting and transporting layer is not necessarily uniform as long as it has such a composition, and a structure having a concentration gradient in the film thickness direction may be employed.

The high-resistance inorganic electron injecting and transporting layer is usually in an amorphous state.

The thickness of the high resistance inorganic electron injecting and transporting layer is preferably from 0.3 to 30 nm, particularly preferably from about 1 to 20 nm. If the electron injection layer is thinner or thicker than this, the function as the electron injection layer cannot be sufficiently exhibited.

As a method for manufacturing the above-mentioned inorganic electron injecting and transporting layer having a high resistance, various physical or chemical thin film forming methods such as a sputtering method and a vapor deposition method can be considered, but the sputtering method is preferable. Among them, multi-source sputtering for separately sputtering the targets of the first component and the second component is preferable. By using multi-source sputtering, a sputtering method suitable for each target can be used. Also, 1
In the case of the original sputtering, a mixed target of the first component and the second component may be used.

When a high-resistance inorganic electron injecting and transporting layer is formed by sputtering, the pressure of the sputtering gas during sputtering is
The range is preferably from 0.1 to 1 Pa. The sputtering gas is an inert gas used in a normal sputtering apparatus, for example, Ar,
Ne, Xe, Kr, etc. can be used. Also, if necessary, N
₂ may be used. As an atmosphere at the time of sputtering, reactive sputtering may be performed by mixing about 1 to 99% of O ₂ in addition to the above-mentioned sputtering gas.

As the sputtering method, a high frequency sputtering method using an RF power source, a DC sputtering method, or the like can be used. The power of the sputtering apparatus is preferably in the range of 0.1 to 10 W / cm ² by RF sputtering, and the film formation rate is preferably in the range of 0.5 to 10 nm / min, particularly 1 to 5 nm / min.

The substrate temperature during film formation is room temperature (25
C) to about 150C.

The light emitting layer is composed of at least one kind or two or more kinds of organic compound thin films involved in the light emitting function, or a laminated film thereof.

The light emitting layer has a function of injecting holes (holes) and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons. By using a relatively electronically neutral compound for the light emitting layer, electrons and holes can be easily injected and transported in a well-balanced manner.

The thickness of the light emitting layer is not particularly limited and varies depending on the forming method.
It is preferable that the thickness be in the range of 10 to 300 nm.

The light emitting layer of the organic EL device contains a fluorescent substance which is a compound having a light emitting function. Examples of such a fluorescent substance include, for example, JP-A-63-26469.
No. 2 discloses at least one compound selected from compounds such as quinacridone, rubrene, and styryl dyes. Also, Tris (8
Quinolinol derivatives such as metal complex dyes having 8-quinolinol or a derivative thereof as a ligand, such as (quinolinolato) aluminum; tetraphenylbutadiene, anthracene, perylene, coronene, and 12-phthaloperinone derivatives. Further, phenylanthracene derivatives described in JP-A-8-12600 (Japanese Patent Application No. 6-110569), tetraarylethene derivatives described in JP-A-8-12969 (Japanese Patent Application No. 6-114456), and the like are described. Can be used.

Further, it is preferable to use in combination with a host substance capable of emitting light by itself, and it is preferable to use it as a dopant. In such a case, the content of the compound in the light emitting layer is preferably 0.01 to 10% by volume, and more preferably 0.1 to 5% by volume. In the case of rubrene, the content is preferably about 0.01 to 20% by volume. When used in combination with a host substance, the emission wavelength characteristics of the host substance can be changed, light emission shifted to a longer wavelength becomes possible, and the luminous efficiency and stability of the device are improved.

The host substance is preferably a quinolinolato complex, and more preferably an aluminum complex having 8-quinolinol or a derivative thereof as a ligand. Such an aluminum complex is disclosed in JP-A-63-26469.
No. 2, JP-A-3-255190, JP-A-5-7073
3, JP-A-5-258859, JP-A-6-2158
No. 74 and the like.

Specifically, first, tris (8-quinolinolato) aluminum, bis (8-quinolinolato) magnesium, bis (benzo {f} -8-quinolinolato) zinc, bis (2-methyl-8-quinolinolato) aluminum Oxide, tris (8-quinolinolato) indium,
Tris (5-methyl-8-quinolinolato) aluminum, 8-quinolinolatolithium, tris (5-chloro-
8-quinolinolato) gallium, bis (5-chloro-8-
Quinolinolato) calcium, 5,7-dichloro-8-quinolinolatoaluminum, tris (5,7-dibromo-
8-hydroxyquinolinolato) aluminum and poly [zinc (II) -bis (8-hydroxy-5-quinolinyl) methane].

In addition to 8-quinolinol or a derivative thereof, an aluminum complex having another ligand may be used, such as bis (2-methyl-
8-quinolinolato) (phenolato) aluminum (III)
, Bis (2-methyl-8-quinolinolato) (ortho-
Cresolato) aluminum (III), bis (2-methyl-
8-quinolinolato) (meth-cresolate) aluminum
(III), bis (2-methyl-8-quinolinolato) (para-cresolato) aluminum (III), bis (2-methyl-8-quinolinolato) (ortho-phenylphenolate)
Aluminum (III), bis (2-methyl-8-quinolinolato) (meth-phenylphenolato) aluminum (II
I), bis (2-methyl-8-quinolinolato) (para-
Phenylphenolato) aluminum (III), bis (2-
Methyl-8-quinolinolato) (2,3-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolato) aluminum (III), bis (2-methyl- 8-quinolinolato)
(3,4-dimethylphenolato) aluminum (III),
Bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (3,5-di-tert-butylphenolato) aluminum (III) ), Bis (2-methyl-8)
-Quinolinolato) (2,6-diphenylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,4,6-triphenylphenolato) aluminum (III), bis (2-methyl- 8-quinolinolato)
(2,3,6-trimethylphenolato) aluminum (I
II), bis (2-methyl-8-quinolinolato) (2,
3,5,6-tetramethylphenolato) aluminum (I
II), bis (2-methyl-8-quinolinolato) (1-naphthrat) aluminum (III), bis (2-methyl-8
-Quinolinolato) (2-naphthrat) aluminum (II
I), bis (2,4-dimethyl-8-quinolinolato)
(Ortho-phenylphenolato) aluminum (III),
Bis (2,4-dimethyl-8-quinolinolato) (para-
Phenylphenolato) aluminum (III), bis (2,
4-dimethyl-8-quinolinolato) (meta-phenylphenolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2 4-dimethyl-8
-Quinolinolato) (3,5-di-tert-butylphenolato) aluminum (III), bis (2-methyl-4-ethyl-8-quinolinolato) (para-cresolato) aluminum (III), bis (2-methyl) -4-methoxy-8-quinolinolato) (para-phenylphenolato) aluminum (III), bis (2-methyl-5-cyano-8-quinolinolato) (ortho-cresolato) aluminum (III),
Bis (2-methyl-6-trifluoromethyl-8-quinolinolato) (2-naphthrat) aluminum (III);

In addition, bis (2-methyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (2-
Methyl-8-quinolinolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) aluminum
(III) -μ-oxo-bis (2,4-dimethyl-8-quinolinolato) aluminum (III), bis (4-ethyl-
2-methyl-8-quinolinolato) aluminum (III)-
μ-oxo-bis (4-ethyl-2-methyl-8-quinolinolato) aluminum (III), bis (2-methyl-4
-Methoxyquinolinolato) aluminum (III) -μ-oxo-bis (2-methyl-4-methoxyquinolinolato)
Aluminum (III), bis (5-cyano-2-methyl-
8-quinolinolato) aluminum (III) -μ-oxo-
Bis (5-cyano-2-methyl-8-quinolinolato) aluminum (III), bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) -μ
-Oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) and the like.

Other host materials are disclosed in
Phenylanthracene derivative described in JP-A-12600 (Japanese Patent Application No. 6-110569) and JP-A-8-1296
No. 9 (Japanese Patent Application No. 6-114456) is also preferable.

The light emitting layer may also serve as an electron injection / transport layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. These fluorescent substances may be deposited.

The light emitting layer is preferably a mixed layer of at least one kind of hole injecting and transporting compound and at least one kind of electron injecting and transporting compound, if necessary.
Further, it is preferable that a dopant is contained in the mixed layer. The content of the compound in such a mixed layer is preferably 0.01 to 20% by volume, more preferably 0.1 to 15% by volume.

In the mixed layer, a carrier hopping conduction path is formed, so that each carrier moves in a material having a favorable polarity, and injection of a carrier having the opposite polarity is less likely to occur, so that the organic compound is less likely to be damaged. This has the advantage that the element life is extended. Further, by including the above-described dopant in such a mixed layer, the emission wavelength characteristics of the mixed layer itself can be changed, the emission wavelength can be shifted to a longer wavelength, and the emission intensity is increased, The stability of the device can be improved.

The hole injecting / transporting compound and the electron injecting / transporting compound used in the mixed layer may be selected from the following hole injecting / transporting compounds and electron injecting / transporting compounds, respectively.

As the compound capable of injecting and transporting electrons, it is preferable to use a quinoline derivative, furthermore a metal complex having 8-quinolinol or a derivative thereof as a ligand, particularly tris (8-quinolinolato) aluminum (Alq3). It is also preferable to use the above-mentioned phenylanthracene derivatives and tetraarylethene derivatives.

As the compound capable of injecting and transporting holes, an amine derivative having strong fluorescence, for example, a triphenyldiamine derivative which is the above-described hole transporting material, a styrylamine derivative, or an amine derivative having an aromatic condensed ring is used. Is preferred.

The mixing ratio in this case depends on the respective carrier mobilities and carrier concentrations. In general, the weight ratio of the compound having a hole injecting / transporting compound / the compound having an electron injecting / transporting function is from 1/99 to more. 99/1, more preferably 10/90 to 90/10, particularly preferably 20/80
It is preferable to set it to about 80/20.

The thickness of the mixed layer is preferably not less than the thickness corresponding to one molecular layer and less than the thickness of the organic compound layer. Specifically, the thickness is preferably 1 to 85 nm, more preferably 5 to 60 nm, particularly preferably 5 to 50 nm.

As a method of forming the mixed layer, co-evaporation in which evaporation is performed from different evaporation sources is preferable. However, when the vapor pressures (evaporation temperatures) are approximately the same or very close, they are mixed in advance in the same evaporation board. Alternatively, it can be deposited. In the mixed layer, it is preferable that the compounds are uniformly mixed, but in some cases, the compounds may exist in an island shape. The light-emitting layer is generally formed to a predetermined thickness by vapor-depositing an organic fluorescent substance or by dispersing and coating the resin in a resin binder.

The conditions for vacuum deposition are not particularly limited.
The degree of vacuum is 0 ^-4 Pa or less, and the deposition rate is 0.01 to 1 nm /
It is preferable to set it to about sec. 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 occurrence and growth of dark spots can be suppressed.

In the case where a plurality of compounds are contained in one layer when a vacuum evaporation method is used for forming each of these layers, it is preferable to co-deposit each boat containing the compounds by individually controlling the temperature.

The organic EL device of the present invention comprises:
A high-resistance inorganic hole transport layer is provided between the hole injection layer and the hole injection layer.

As described above, by disposing a high-resistance inorganic hole transport layer having a hole conduction path and capable of blocking electrons between the light emitting layer and the organic hole injection layer, the holes can be efficiently transferred to the light emitting layer. Injection can be performed well, the luminous efficiency is improved, and the driving voltage is reduced.

Preferably, silicon or a metal or semimetal oxide such as germanium is used as the main component of the high-resistance inorganic hole transport layer, and the work function is 4.5 eV or more, preferably 4.5 to 6 eV. Metal, semi-metal and / or
Alternatively, a hole is efficiently injected from the hole injection layer into the organic layer on the light emitting layer side by forming a conductive path containing at least one of these oxides, carbides, nitrides, silicides, and borides. can do. In addition, the movement of electrons from the light emitting layer to the hole injection electrode side can be suppressed, and the recombination of holes and electrons in the light emitting layer can be performed efficiently. In addition, an organic EL having both the advantages of an inorganic material and the advantages of an organic material
It can be an element. The organic EL device of the present invention can obtain a luminance equal to or higher than that of a device having a conventional organic hole transporting layer, and has a longer life than conventional devices because of high heat resistance and weather resistance, and has a leak and darkness. There are few spots. Further, not only relatively expensive organic substances but also inorganic materials which are inexpensive, easily available and easily manufactured can be used to reduce manufacturing costs.

The resistivity of the high-resistance inorganic hole transport layer is preferably 1 to 1 × 10 ¹¹ Ω · cm, particularly 1 × 10 ³ Ω · cm.
It is 1 × 10 ⁸ Ω · cm. By setting the resistivity of the high-resistance inorganic hole transport layer within the above range, the hole injection efficiency can be dramatically improved while maintaining high electron blocking properties. The resistivity of the high-resistance inorganic hole transport layer is
It can also be determined from the sheet resistance and the film thickness. In this case, the sheet resistance can be measured by a four-terminal method or the like.

The material of the main component is an oxide of silicon or germanium. Preferably, in (Si _1-x Ge _x ) O _y , 0 ≦ x ≦ 1, 1.7 ≦ y ≦ 2.2, preferably 1 0.7 ≦ y ≦ 1.99. The main component of the high-resistance inorganic hole transport layer may be silicon oxide or germanium oxide, or a mixed thin film thereof. If y is larger or smaller than this, the hole injection function tends to decrease. The composition may be determined by, for example, Rutherford backscattering or chemical analysis.

The high-resistance inorganic hole transport layer further contains, in addition to the main component, an oxide, carbide, nitride, silicide, and boride of a metal (including a semimetal) having a work function of 4.5 eV or more. Is preferred. A metal having a work function of 4.5 eV or more, preferably 4.5 to 6 eV is preferably Au, C
u, Fe, Ni, Ru, Sn, Cr, Ir, Nb, P
At least one of t, W, Mo, Ta, Pd and Co. These are generally present as metals or in the form of oxides. Moreover, these carbides, nitrides, silicides, and borides may be used. When these are mixed and used, the mixing ratio is arbitrary. Their content is preferably from 0.2 to 40 mol%, more preferably from 1 to 2 mol%.
0 mol%. If the content is less than this, the hole injection function is reduced, and if the content exceeds this, the electron blocking function is reduced. When two or more kinds are used in combination, the total content is preferably in the above range.

The oxides, carbides, nitrides, silicides and borides of the above metals or metals (including semimetals) are usually dispersed in a high-resistance inorganic hole transport layer. The particle size of the dispersed particles is usually about 1 to 5 nm. It is considered that a hopping path for transporting holes between the dispersed particles as conductors via the high-resistance main component is formed.

In the high-resistance inorganic hole transport layer, H, Ne, Ar, K
r, Xe, etc. may be contained in a total of 5 at% or less.

If the average value of the entire high-resistance inorganic hole transport layer is such a composition, the composition may not be uniform and may have a structure having a concentration gradient in the film thickness direction.

The high-resistance inorganic hole transport layer is usually in an amorphous state.

The thickness of the high-resistance inorganic hole transport layer is preferably 0.2 to 100 nm, more preferably 0.1 to 100 nm.
The thickness is preferably 2 to 30 nm, particularly preferably about 0.2 to 10 nm. Even if the high-resistance inorganic hole transport layer is thinner or thicker, the function as the hole transport layer cannot be sufficiently exhibited.

As a method for manufacturing the above-described inorganic hole transporting layer having a high resistance, various physical or chemical thin film forming methods such as a sputtering method and a vapor deposition method can be considered, but the sputtering method is preferable. Among them, multi-source sputtering in which the above main component and a target such as a metal or a metal oxide are separately sputtered is preferable. By using multi-source sputtering, a sputtering method suitable for each target can be used. Further, in the case of one-source sputtering, the composition may be adjusted by arranging small pieces of the above metal or metal oxide on the target of the main component and appropriately adjusting the area ratio of the two.

When a high-resistance inorganic hole transport layer is formed by sputtering, the film forming conditions and the like are the same as those for the high-resistance inorganic electron injection / transport layer.

Since the organic EL device of the present invention has a high-resistance inorganic hole transport layer, heat resistance and weather resistance are improved, and the life of the device can be extended. In addition, since an inexpensive and easily available inorganic material is used instead of a relatively expensive organic substance, the production becomes easy and the production cost can be reduced. Further, the connectivity with the electrode, which is an inorganic material, which has been a problem in the past, is improved. For this reason, generation of a leak current and generation of a dark spot can be suppressed.

The organic EL device of the present invention has an organic hole injection layer as an organic layer in addition to the above-mentioned light emitting layer in addition to the inorganic hole transport layer.

For the hole injection layer made of an organic material, it is preferable to use the hole injection / transport material shown in the light emitting layer.

The hole transporting layer is described in, for example,
No. 295,695, JP-A-2-191694,
JP-A-3-792, JP-A-5-234681, JP-A-5-239455, JP-A-5-299
Various organic compounds described in JP-A-174, JP-A-7-126225, JP-A-7-126226, JP-A-8-100172, EP0650955A1, and the like can be used. For example, a tetraarylbendicine compound (triaryldiamine or triphenyldiamine: TPD), an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an oxadiazole derivative having an amino group, polythiophene, etc. . These compounds may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be stacked as separate layers or mixed.

The thickness of the organic hole injection layer is not particularly limited and varies depending on the forming method, but it is usually preferably about 5 to 500 nm, particularly preferably 10 to 300 nm.

For forming the light emitting layer and the organic hole injection layer,
It is preferable to use a vacuum evaporation method since a uniform thin film can be formed. When a vacuum deposition method is used, a homogeneous thin film having an amorphous state or a crystal grain size of 0.2 μm or less can be obtained. If the crystal grain size exceeds 0.2 μm, the light emission becomes non-uniform, the driving voltage of the device must be increased, and the injection efficiency of electrons and holes is significantly reduced.

The conditions for vacuum deposition are not particularly limited.
The degree of vacuum is 0 ^-4 Pa or less, and the deposition rate is 0.01 to 1 nm /
It is preferable to set it to about sec. 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 occurrence and growth of dark spots can be suppressed.

In the case where a plurality of compounds are contained in one layer when a vacuum evaporation method is used for forming each of these layers, it is preferable to co-deposit each boat containing the compounds by individually controlling the temperature.

Further, in order to prevent the deterioration of the organic layer and the electrodes of the device, it is preferable to seal the device with a sealing plate or the like. The sealing plate adheres and seals the sealing plate using an adhesive resin layer in order to prevent moisture from entering. The sealing gas is A
An inert gas such as r, He, N ₂ or the like is preferable. Further, the moisture content of the sealing gas is preferably 100 ppm or less, more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Although there is no particular lower limit for the water content, it is usually about 0.1 ppm.

The material of the sealing plate is preferably a flat plate, and may be a transparent or translucent material such as glass, quartz, resin, etc., but glass is particularly preferred. As such a glass material, an alkali glass is preferable from the viewpoint of cost, and in addition, a glass composition such as soda lime glass, lead alkali glass, borosilicate glass, aluminosilicate glass, and silica glass is also preferable. In particular, soda glass, a glass material without surface treatment can be used at low cost,
preferable. As the sealing plate, other than a glass plate, a metal plate, a plastic plate, or the like can be used.

The height of the sealing plate may be adjusted to a desired height by using a spacer. Examples of the material of the spacer include resin beads, silica beads, glass beads, and glass fibers, and glass beads are particularly preferable. The spacer is usually a granular material having a uniform particle size, but the shape is not particularly limited, and may be various shapes as long as it does not hinder the function as the spacer. As the size, the diameter in terms of a circle is 1 to 20 μm, more preferably 1 to 10 μm, and especially 2 to 20 μm.
8 μm is preferred. Those having such a diameter have a grain length of 10
It is preferably about 0 μm or less, and the lower limit is not particularly limited, but is usually about the same as or larger than the diameter.

When a recess is formed in the sealing plate,
Spacers may or may not be used. The preferred size when used is within the above range,
Particularly, the range of 2 to 8 μm is preferable.

The spacer may be mixed in the sealing adhesive in advance or may be mixed at the time of bonding. The content of the spacer in the sealing adhesive is preferably 0.01
-30 wt%, more preferably 0.1-5 wt%.

The adhesive is not particularly limited as long as it can maintain stable adhesive strength and has good airtightness, but it is preferable to use a cationic curing type ultraviolet curing epoxy resin adhesive. .

In the present invention, the substrate on which the organic EL structure is formed is an amorphous substrate such as glass or quartz, or a crystalline substrate such as Si, GaAs, ZnSe, or Z.
Examples include nS, GaP, and InP, and a substrate in which a crystalline, amorphous, or metal buffer layer is formed on these crystalline substrates can also be used. As the metal substrate, Mo, Al, Pt, Ir, Au, Pd, or the like can be used, and a glass substrate is preferably used. When the substrate is on the light extraction side, it is preferable that the substrate has the same light transmittance as the above-mentioned electrodes.

Further, a large number of the elements of the present invention may be arranged on a plane. By changing the emission color of each element arranged on a plane, a color display can be obtained.

The luminescent color may be controlled by using a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film on the substrate.

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

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 instead of the color filter.

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 desirable that the fluorescent material has strong absorption in the EL emission wavelength region. In practice, laser dyes and the like are suitable, and rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalocyanines, etc.) naphthaloimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds A styryl compound, a coumarin compound or the like may be used.

As the binder, basically, a material which does not quench the fluorescence may be selected, and a binder which can be finely patterned by photolithography, printing or the like is preferable. In the case where the hole injection electrode is formed on the substrate in contact with the hole injection electrode, a material which is not damaged when the hole injection electrode (ITO, IZO) is formed 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.

The organic EL device of the present invention is usually used as a DC drive type or pulse drive type EL device, but it can be AC drive. The applied voltage is usually 2 to 30
V.

As shown in FIG. 1, for example, the organic EL device of the present invention comprises a substrate 1 / a hole injection electrode 2 / an organic hole injection layer 3 / a high resistance inorganic hole transport layer 4 / a light emitting layer 5 / a high resistance Inorganic electron injection / transport layer 6 / negative electrode (electron injection electrode) 7
May be sequentially laminated. Further, a so-called reverse lamination configuration in which the above lamination order is reversed may be adopted. These are appropriately selected and used depending on, for example, the specifications of the display and the manufacturing process. In FIG. 1, a driving power source E is connected between the hole injection electrode 2 and the negative electrode 7.

The elements of the present invention may be stacked in multiple layers in the film thickness direction. With such an element structure, it is also possible to adjust the color tone of the emitted light and to make it multicolored.

The organic EL element of the present invention can be used not only as a display but also as various optical applications such as an optical pickup used for memory read / write, a relay device in a transmission line of optical communication, a photocoupler, and the like. Can be used for devices.

[0103]

<Example 1> A 7059 substrate (trade name, manufactured by Corning Incorporated) as a glass substrate was scrub-cleaned using a neutral detergent.

An ITO hole injection electrode layer having a thickness of 200 nm was formed on this substrate at a substrate temperature of 250 ° C. by an RF magnetron sputtering method using an ITO oxide target.

After the surface of the substrate on which the ITO electrode layer and the like had been formed was washed with UV / O _3, it was fixed to a substrate holder of a vapor deposition apparatus, and the pressure in the tank was reduced to 1 × 10 ⁻⁴ Pa or less.

M-MTDATA was deposited at a deposition rate of 0.2 nm / se.
A hole injection layer was formed by evaporating to a thickness of 40 nm with c.

Then, a high-resistance inorganic hole transport layer was formed to a thickness of 2 nm by using SiO _{2 as} a target and Au pellets having a predetermined size placed thereon. The sputtering gas at this time was Ar: 30 sccm, O ₂ : 5 sccm,
At room temperature (25 ° C.), the deposition rate was 1 nm / min, the operating pressure was 0.2 to 2 Pa, and the input power was 500 W. The composition of the formed high-resistance inorganic hole injecting and transporting layer is such that Au _1.9
Was contained at 4 mol%.

Further, while maintaining the reduced pressure, it was transferred to a vapor deposition apparatus, and N, N, N ', N'-tetrakis (m-biphenyl) -1,1'-biphenyl-4,4'-diamine (T
PD), tris (8-quinolinolato) aluminum (Alq3) and rubrene at an overall deposition rate of 0.2
The film was deposited to a thickness of 40 nm at nm / sec to form a light emitting layer. T
PD: Alq3 = 1: 1 (weight ratio), and this mixture was doped with 5% by volume of rubrene.

Next, the substrate was transferred to a sputtering apparatus, and Li
Using a target in which V was mixed with 4 mol% of ₂ O, a high-resistance inorganic electron injecting and transporting layer was formed to a thickness of 10 nm. The sputtering gas at this time is Ar: 30 sccm, O ₂ : 5 sccm
At room temperature (25 ° C.), the deposition rate was 1 nm / min, the operating pressure was 0.2 to 2 Pa, and the input power was 500 W. The composition of the formed inorganic electron injection layer was almost the same as that of the target.

Then, while keeping the reduced pressure, Al was vapor-deposited to a thickness of 200 nm by a sputtering method to form a negative electrode, and finally glass sealing was performed to obtain an organic EL device.

When an electric field was applied to the obtained organic EL device in air, the device showed diode characteristics. When the ITO side was biased positively and the AlLi / Al electrode side was biased negatively, the current increased as the voltage increased. However, clear light emission was observed in a normal room. Further, even when the light emitting operation was repeatedly performed, no decrease in luminance was observed.

The obtained organic EL device was air-conditioned at 10 mA.
/ Cm ^{2 at} a constant current density, the initial luminance was 10
The driving voltage was 6.9 V at 00 cd / m ² . When the sheet resistance of the inorganic hole transport layer having a high resistance was measured by a four-terminal method, the sheet resistance at a film thickness of 100 nm was 500Ω
/ Cm ² , which was 5 × 10 ⁷ Ω · cm in terms of resistivity.

<Example 2> In Example 1, the composition of the high-resistance inorganic electron injection layer was changed from Li ₂ O to Na, K, R
b, alkali metal elements of Cs and Fr, or Be,
Alkaline earth metal elements of Mg, Ca, Sr, Ba and Ra, or La, Ce, Pr, Nd, Pm, Sm, E
Similar results were obtained by substituting an oxide of one or more elements selected from lanthanoid elements of u, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

Further, from V, Ru, Zn, Sm and In
The same was true even when one or more elements selected from

<Embodiment 3> In Embodiments 1 and 2, when forming a high-resistance inorganic hole transport layer, Ge was used as a target.
O ₂ and Au pellets of a predetermined size were arranged on the target, and a high-resistance inorganic hole transport layer was formed to a thickness of 20 nm. The sputtering gas at this time is Ar: 30 sc
cm, O ₂ : 5 sccm, room temperature (25 ° C.), film formation rate 1n
m / min, operating pressure 0.2 to 2 Pa, and input power 500 W. The composition of the formed inorganic hole transporting layer was such that GeO ₂ contained 2 mol% of Au.

Otherwise, an organic EL device was obtained in the same manner as in Example 1. When the obtained organic EL device was evaluated in the same manner as in Example 1, almost the same results as in Example 1 were obtained.

<Embodiment 4> In Embodiments 1 and 2, when a high-resistance inorganic hole transport layer is formed, O
_{2 The} target was changed according to the flow rate and the film composition, and the composition of the main component was changed to SiO _1.7 , SiO _1.95 , GeO _1.96 , S
An organic EL device was prepared in the same manner as in Example 1 except that i _0.5 Ge _0.5 O _{1.92 was used,} and the luminance was evaluated. As a result, almost the same results were obtained.

<Example 5> In Examples 1 and 2, the metal of the high-resistance inorganic hole transport layer was changed from Au to Cu, Fe,
Ni, Ru, Sn, Cr, Ir, Nb, Pt, W, M
Similar results were obtained by replacing any one or more of o, Ta, Pd and Co, or their oxides, carbides, nitrides, silicides and borides.

<Comparative Example> In Example 1, after an ITO hole injection electrode was formed, MTDATA was formed by vapor deposition.
Is deposited at a deposition rate of 0.1 nm / sec to a thickness of 10 nm to form a hole injection layer, and TPD is deposited at a deposition rate of 0.1 nm / sec.
To form a hole transport layer by evaporation to a thickness of 20 nm. After forming the light emitting layer, tris (8-quinolinolato) aluminum (Alq3) was further deposited at a deposition rate of 0.2.
Vapor deposition was performed at a thickness of 40 nm at a rate of nm / sec to form an organic electron injection / transport layer.

Next, while maintaining the reduced pressure, AlLi (L
i: 7 at%) to a thickness of 1 nm, followed by Al
Evaporation was performed to a thickness of 0 nm to form an electron injection electrode and an auxiliary electrode, and finally, glass sealing was performed to obtain an organic EL device. Otherwise, an organic EL device was prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1. As a result, the initial luminance at a constant current density of 10 mA / cm ² was 750 cd / m ² .

[0121]

As described above, according to the present invention, it is possible to provide an organic EL element having both the advantages of an organic material and an inorganic material, and having high efficiency, long life and low cost.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first basic configuration of an organic EL device of the present invention.

FIG. 2 is a schematic cross-sectional view showing a configuration example of a conventional organic EL element.

FIG. 3 is a schematic sectional view showing another configuration example of a conventional organic EL element.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 hole injection electrode 3 organic hole injection layer 4 high-resistance inorganic hole transport layer 5 light-emitting layer 6 high-resistance inorganic electron injection / transport layer 7 negative electrode (electron injection electrode) 11 substrate 12 hole injection electrode 13 electron injection electrode 14 Hole transport layer 15 Light emitting layer 16 Electron transport layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Etsuo Mitsuhashi 1-13-1, Nihonbashi, Chuo-ku, Tokyo TDK Corporation F-term (reference) 3K007 AB00 AB03 AB18 BB01 BB06 CA00 CA01 CA02 CA04 CB01 DA00 DB03 EB00 EC00 FA01 FA03

Claims (13)

[Claims] 1. A light-emitting device comprising: a hole injection electrode, a negative electrode, and an organic layer having at least a light-emitting layer between these electrodes. The hole is blocked and electrons are transported between the light-emitting layer and the negative electrode. A high-resistance inorganic electron injecting and transporting layer having a conductive path for blocking the electrons between the light emitting layer and the hole injecting electrode and having a conductive path for transporting holes. An organic EL device having a transport layer and having an organic hole injection layer between the high-resistance inorganic hole transport layer and the hole injection electrode. 2. The organic EL device according to claim 1, wherein the high-resistance inorganic hole transport layer has a resistivity of 1 to 1 × 10 ¹¹ Ω · cm. 3. The high-resistance inorganic hole transporting layer contains at least one of a metal and / or an oxide, carbide, nitride, silicide, and boride of the metal.
Or 2 organic EL elements. 4. The high-resistance inorganic hole transporting layer contains silicon and / or germanium oxide as a main component, and when this main component is expressed as (Si _1-x Ge _x ) O _y , 0 ≦ x ≦ 1, 1.7 ≦ y ≦ 2.2, and further contains any one or more of metals and / or oxides, carbides, nitrides, silicides, and borides of metals having a work function of 4.5 eV or more. The organic EL device according to claim 1, wherein: 5. The method according to claim 1, wherein the metal is Au, Cu, Fe, Ni,
Ru, Sn, Cr, Ir, Nb, Pt, W, Mo, T
5. The composition according to claim 4, which is at least one of a, Pd and Co.
Organic EL device. 6. The metal and / or an oxide of the metal,
The contents of carbides, nitrides, silicides and borides are:
6. The organic EL according to claim 4, which is 0.2 to 40 mol%.
element. 7. The organic EL device according to claim 1, wherein said high-resistance inorganic hole transport layer has a thickness of 0.2 to 100 nm. 8. The inorganic electron injecting layer having a high resistance has a work function of 4 eV or less as a first component, and at least one element selected from an alkali metal element, an alkaline earth metal element, and a lanthanoid element. The organic EL device according to any one of claims 1 to 7, comprising an oxide and at least one metal having a work function of 3 to 5 eV as a second component. 9. The second component comprises Zn, Sn, V, R
9. The organic EL device according to claim 8, wherein the device is at least one selected from u, Sm, and In. 10. The alkali metal element is Li, N
a, K, Rb, Cs and Fr; at least one of alkaline earth metal elements is at least one of Mg, Ca and Sr; and the lanthanoid element is at least one of La and Ce. The organic EL device according to claim 8, wherein 11. The organic EL device according to claim 1, wherein the high-resistance inorganic electron injection layer has a resistivity of 1 to 1 × 10 ¹¹ Ω · cm. 12. The high-resistance inorganic electron injecting layer comprises a second
The organic EL device according to any one of claims 8 to 11, wherein the component is contained in an amount of 0.2 to 40 mol% based on all components. 13. The organic EL device according to claim 1, wherein the high-resistance inorganic electron injection layer has a thickness of 0.3 to 30 nm.