JP2000113976A - Organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life organic EL element capable of being easily manufactured, excluding the effect of moisture to the utmost, reducing aging deterioration, particularly the expansion of a nonluminescent area and the change of luminance, and capable of maintaining initial performance for a long period. SOLUTION: An organic EL structure provided with a hole injection electrode, an electron injection electrode and organic layers including one or more kinds of luminescence layers provided between these electrodes is stored in an airtight case, and one or more kinds of calcium hydride, strontium hydride, barium hydride and aluminum hydride lithium are arranged in the airtight case to form this organic EL element. The electron injection electrode contains one or more kinds of an alkaline metal and an alkaline earth metal. At least one layer of the organic layers contains one or more kinds of the alkaline metal and the alkaline earth metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an organic EL device using an organic compound.

[0002]

2. Description of the Related Art In recent years, organic EL devices have been actively studied. In this method, a hole transport material such as triphenyldiamine (TPD) is formed into a thin film by vapor deposition on a transparent electrode (hole injection electrode) such as tin-doped indium oxide (ITO) and a fluorescent material such as aluminum quinolinol complex (Alq3) is formed thereon. An element having a basic structure in which a substance is laminated as a light emitting layer and a metal electrode (electron injection electrode) having a small work function, such as Mg, is formed. The voltage is about several hundreds to several 10,000 cd / m ² at a voltage of about 10 V. Attention has been paid to high brightness.

As a material used as an electron injection electrode of such an organic EL device, a material that injects a large amount of electrons into a light emitting layer, an electron injection transport layer, or the like is considered to be effective.
In other words, it can be said that a material having a smaller work function is more suitable as an electron injection electrode. There are various materials having a low work function. Examples of materials used as an electron injection electrode of an organic EL device include, for example, JP-A No. 2-15 / 1990.
No. 595 discloses an electron injecting electrode comprising a plurality of metals other than alkali metals and having a work function of at least one of these metals of less than 4 eV, such as M
gAg is disclosed.

An alkali metal having a small work function is preferable. US Pat. Nos. 3,173,050 and 3,382,394 disclose, for example, NaK as an alkali metal. In particular, L
When i is used, a high-luminance organic EL element can be obtained.

[0005] Electron injection electrodes using an alkali metal are described, for example, in JP-A-60-165977, JP-A-4-212287, JP-A-5-121172, and JP-A-5-159882. A
An electron injection electrode using an lLi alloy is known. The Li concentration of the AlLi alloy described in these publications is as follows: (1) According to Japanese Patent Application Laid-Open No. 60-165771, the Li concentration is 3.6 to 99.8 at% (1 to 99 wt%).
%), Preferably 29.5 to 79.1 at% (10 to 50%).
wt%) AlLi alloy is described. (2) In JP-A-4-212287, the Li concentration is 6 at% or more,
Preferably, an AlLi alloy of 6 to 30 at% is described. (3) In JP-A-5-121172, the Li concentration is 0.0377 to 0.38 at% (0.01 to 0.1:
AlLi alloy having a Li concentration of 15.9 at% or less (50 or less: 100 wt ratio).
Li alloys are described. (4) JP-A-5-1598
No. 82 describes an AlLi alloy having a Li concentration of 5 to 90 at%.

Furthermore, in Japanese Patent Application Laid-Open No. Hei 9-17574, an alkali metal (Li,
Compounds of Na, K, Rb and Cs), in particular, oxides, peroxides, complex oxides, halides, nitrides and alkali metal salts of alkali metals are disclosed. Specifically, L
i ₂ O, Li ₂ O ₂ , LiAlO ₂ , LiBO ₃ , LiC
1, Li ₂ CO _{3 and the} like.

In Japanese Patent Application Laid-Open No. 10-74586, as an electron injection electrode, an alkali fluoride, an alkaline earth fluoride, specifically, LiF, MgF ₂ , MgCa ₂
Is disclosed.

However, a material having a small work function, such as Li, has high reactivity to oxygen and moisture and is chemically unstable. An organic EL element using an electron injection electrode containing an alkali metal such as Li can obtain extremely high luminance, but has a problem that the luminance increases during driving. This is because the interface between the electrode and the organic layer is annealed by the heat generated during driving, the I (current) -V (voltage) curve changes with the driving time, and the current value increases even with the same applied voltage. Note that the I (current) -L (luminance) curve hardly changes with the driving time.

Also, when an alkaline earth metal such as MgAg is used for the electron injection electrode, there is a problem that the luminance increases during driving, as in the case of the alkali metal.

Incidentally, the organic EL element has a problem that it is very weak to moisture. Due to the influence of moisture, for example, separation occurs between the light-emitting layer and the electrode layer, or a constituent material is altered, a non-light-emitting region called a dark spot is generated, or a light-emitting area is reduced. As a result, light emission of a predetermined quality cannot be maintained.

As a method for solving this problem, for example, JP-A-5-36475 and JP-A-5-89959
As described in Japanese Patent Application Laid-Open Nos. 7-169567 and 7-169567, a technique for tightly fixing an airtight case, a sealing layer, and the like covering an organic EL layered structure portion on a substrate and shutting off the outside is known. ing.

However, even if such a sealing layer or the like is provided, the light emission luminance is reduced, a dark spot is formed, or the light spot is enlarged due to the influence of moisture entering from the outside as the drive time elapses. As a result, the light emitting area is reduced, the element is deteriorated, and as a result, the light emitting failure becomes worse and the device becomes unusable.

It has been proposed that the organic EL structure is housed in an airtight case and a desiccant is placed in the case. For example, Japanese Patent Application Laid-Open No. 3-261091 discloses that
Diphosphorus pentoxide as a drying agent (P ₂ O ₅₎ is disclosed. However, P ₂ O ₅ absorbs water and dissolves (deliquescence) in the water to become phosphoric acid, which adversely affects the organic EL structure. Also, the method of encapsulating P ₂ O ₅ is extremely limited,
Not practical.

Japanese Unexamined Patent Publication (Kokai) No. 6-176867 discloses fine powder solid dehydrating agents, specifically, zeolite, activated alumina, silica gel, and calcium oxide. However, a desiccant such as zeolite that physically adsorbs moisture releases the adsorbed moisture due to heat generated when the organic EL element emits light, so that a sufficient life cannot be obtained.

On the other hand, Japanese Unexamined Patent Publication No. Hei 9-148066 discloses a compound which adsorbs moisture as a drying agent and maintains a solid state even when it absorbs moisture. Earth metal oxides, sulfates,
Metal halides are mentioned. Since these compounds chemisorb water, no re-release of water occurs and the life of the device is prolonged. However, the life of the device is still insufficient.

The present inventors have disclosed in Japanese Patent Application No. 10-181458.
Proposes to use calcium hydride and / or lithium aluminum hydride as a desiccant. When these are used as a desiccant, the life of the organic EL element is dramatically increased. However, this has a remarkable effect on the element deterioration due to the enlargement of the non-light emitting area, which has been a problem in the past, but has a problem that the luminance decreases with the driving time. This is because the I (current) -V (voltage) curve changes with the driving time, and the current value decreases even with the same applied voltage. Note that the I (current) -L (luminance) curve hardly changes with the driving time.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to make it easy to manufacture, to eliminate the influence of moisture and the like as much as possible, to reduce the deterioration over time, especially to enlarge the non-light-emitting area, to reduce the change in luminance, and to improve the initial performance for a long time. An object of the present invention is to provide a long-life organic EL element that can be maintained.

[0018]

Such an object can be achieved by the following constitution.

(1) An organic EL structure having a hole injection electrode, an electron injection electrode, and an organic layer including one or more light emitting layers provided between these electrodes is housed in an airtight case. In the airtight case, calcium hydride,
An organic EL device in which at least one of strontium hydride, barium hydride, and lithium aluminum hydride is disposed, and wherein the electron injection electrode contains at least one of an alkali metal and an alkaline earth metal. (2) The organic EL device according to (1), wherein the thickness of the electron injection electrode is 1 nm or less. (3) The organic EL device according to the above (1) or (2), wherein at least one of the organic layers contains at least one of an alkali metal and an alkaline earth metal. (4) An organic EL structure including a hole injection electrode, an electron injection electrode, and an organic layer including one or more light emitting layers provided between these electrodes is housed in an airtight case,
In the hermetic case, at least one of calcium hydride, strontium hydride, barium hydride and lithium aluminum hydride is disposed, and at least one of the organic layers is formed of any one of an alkali metal and an alkaline earth metal. Or an organic EL device containing at least one of them. (5) The method according to (3), wherein the organic layer has an electron injection layer between the electron injection electrode and the light emitting layer, and the electron injection layer contains at least one of an alkali metal and an alkaline earth metal. ) Or (4). (6) The electron injecting electrode contains one or more of alkali metal alloys, oxides thereof, fluorides thereof, alloys of alkaline earth metals, oxides thereof, and fluorides thereof. The organic EL device according to any one of (1), (2), (3) and (5). (7) The organic EL device according to any one of (1) to (6), wherein the electron injection electrode and / or the organic layer contains lithium. (8) The organic EL device according to (7), wherein the electron injection electrode contains at least one of an aluminum lithium alloy, lithium oxide, and lithium fluoride. (9) The organic EL according to any one of (3), (4), (5) and (7) above, wherein the content of the alkali metal and / or alkaline earth metal in the organic layer is 0.1 to 10% by weight. element. (10) The hermetic case includes a substrate on which the organic EL structure is laminated, a sealing plate provided with a predetermined gap on the organic EL structure, and the sealing plate provided on the substrate. The organic EL device according to any one of the above (1) to (9), further comprising: a sealing adhesive that adheres to the organic EL device. (11) The organic EL device according to the above (10), wherein the void is filled with nitrogen, and calcium hydride and / or strontium hydride is disposed in the airtight case.

[0020]

The organic EL device of the present invention comprises a hole injection electrode,
An organic EL structure having an electron injection electrode and an organic layer including one or more light emitting layers provided between these electrodes is housed in an airtight case, and the organic EL structure is contained in the airtight case. And at least one of calcium hydride, strontium hydride, barium hydride and lithium aluminum hydride is disposed as a desiccant in a non-contact state. The electron injection electrode contains at least one of an alkali metal and an alkaline earth metal. The thickness of the electron injection electrode is preferably 1 nm or less. Alternatively, at least one of the organic layers, preferably the electron injection layer, contains at least one of an alkali metal and / or an alkaline earth metal. Its content is 0.1-10
It is preferable that the content is wt%, particularly 1-3 wt%.

By placing one or more of calcium hydride, strontium hydride, barium hydride and lithium aluminum hydride, preferably calcium hydride and / or strontium hydride, as a desiccant in the hermetic case. In particular, after sealing, the intruding moisture can be removed and the moisture concentration in the hermetic case can be reduced, so that the non-light-emitting area hardly expands for a long time, and the life of the element is dramatically increased. .

Calcium hydride and lithium aluminum hydride remove water in accordance with the following chemical reaction formula.
Strontium hydride and barium hydride remove water according to the same chemical reaction formula as the following formula for calcium hydride.

[0023] _{CaH 2 + 2H 2 O → Ca} (OH) 2 + 2H 2 AlLiH 4 + 4H 2 O → Li (OH) + Al (OH) 3 + 4H 2

Since the compound (hydroxide) after reacting with water is stably present, the water once removed does not release again. In addition, by using the above-described material as a desiccant, hydrogen is generated along with the removal of water, and the inside of the airtight case becomes a reducing atmosphere. Extends further. Therefore, the life is longer than when the compound disclosed in JP-A-9-148066 is used. Further, according to the above equation, since hydrogen is generated in an equimolar manner when adsorbing water vapor, the change in the internal pressure in the airtight case is extremely small or not, which is preferable in maintaining the hermeticity. The compound disclosed in JP-A-9-148066 is disadvantageous also in this respect.

In addition, since the solid state is maintained even when moisture is absorbed, the element is not adversely affected by disposing the element in a non-contact state with the organic EL structure, and is easily sealed in an airtight case. Can be.

Further, according to the present invention, high brightness can be obtained by the electron injection electrode containing at least one of an alkali metal and an alkaline earth metal, and the film thickness is relatively 1 nm or less as compared with the prior art. By making it thinner and using it together with the desiccant as described above, the luminance hardly fluctuates, and a constant luminance can be obtained for a long time.

Alternatively, high brightness can be achieved by at least one of the organic layers, preferably an organic layer in contact with the electron injection electrode, that is, the electron injection layer contains at least one of an alkali metal and an alkaline earth metal. Is obtained, and when used in combination with the drying agent as described above, the luminance hardly fluctuates, and a constant luminance can be obtained for a long time.
In this case, if the content of the alkali metal and / or the alkaline earth metal is too large or too small, the fluctuation in luminance tends to be large, and the content is preferably 0.1 to 10% by weight. In particular, the content is preferably 1 to 3 wt% in the range of 0 to 50 nm from the interface of the electron injection electrode.

Hydrogen released when the desiccant absorbs and removes moisture has a reducing effect on alkali metals and alkaline earth metals, and the alkali metal contained in the electron injection electrode and / or the electron injection layer. It is considered that the hydrogenation of the alkaline earth metal is stabilized and the luminance does not change. Since hydrogen is excessively present in the airtight case, hydride is stably present.

As described above, the conventional organic EL element uses a material having a small work function as the electron injection electrode, that is, an alkali metal or an alkaline earth metal, and has a problem that the luminance increases with the driving time. there were. On the other hand, the organic EL element of the present invention can stably obtain a constant luminance for a long time, and has a very small change in performance over time. Also, its manufacture is easy.

[0030]

DETAILED DESCRIPTION OF THE INVENTION An organic EL device according to the present invention comprises an organic EL device having a hole injection electrode, an electron injection electrode, and an organic layer including at least one light emitting layer provided between these electrodes.
The structure is housed in an airtight case, and one or more of calcium hydride, strontium hydride, barium hydride, and lithium aluminum hydride are disposed in the airtight case in a non-contact state with the organic EL structure. Have been. Desiccant calcium hydride (CaH ₂ ), strontium hydride (SrH ₂ ), barium hydride (Ba)
The initial composition of H ₂ ) and lithium aluminum hydride (AlLiH ₄ ) may deviate slightly from the stoichiometric composition. These are sealed in a case so as not to come into contact with atmospheric moisture as much as possible.

CaH ₂ , SrH ₂ , BaH ₂ , A
Although the same effect can be obtained by using any of lLiH ₄ , since highly reactive AlLiH ₄ may require the use of Ar as the sealing gas in the hermetic case, N ₂
CaH ₂ , SrH ₂ , and BaH ₂ are more preferable. Since BaH ₂ has poor stability, it is particularly preferable to use CaH ₂ and SrH ₂ as drying agents.

CaH ₂ , SrH ₂ , BaH ₂ , AlLiH ₄
Is in air-tight case, it is preferable to arrange the order of the space 1 mm ³ per 0.0001~0.5mg in airtight case.
If the amount of CaH ₂ , SrH ₂ , BaH ₂ , and AlLiH _{4 to} be arranged is less than this, the water cannot be sufficiently removed. The higher the content of CaH ₂ , SrH ₂ , BaH ₂ , and AlLiH _4, the more water is removed and the life of the device is extended.
Contact with the structure adversely affects the structure. Usually, the upper limit of the amount that can be arranged is about 1 mg / mm ³ . CaH ₂ , S
Even when rH ₂ , BaH ₂ , and AlLiH ₄ are used together, the total amount is preferably within the above range.

CaH ₂ , SrH ₂ , BaH ₂ , AlLiH ₄
May be used as particles, and the average particle size at that time is 0.1.
It is preferably about 01 to 10 μm. If the particle size is larger than this, the surface area decreases, and the water absorption decreases. If it is smaller than this, storage and handling while maintaining the water absorption becomes difficult.

CaH ₂ , SrH ₂ , BaH ₂ , AlLiH ₄
Are arranged so as not to come into contact with the organic EL structure in the airtight case to avoid adverse effects. The arrangement method is not particularly limited. For example, CaH ₂ , SrH ₂ , BaH ₂ , AlL
A method of fixing iH ₄ as a molded body in an airtight case, CaH ₂ , a bag or a container having air permeability such as porous Teflon,
There is a method in which SrH ₂ , BaH ₂ , and AlLiH ₄ are put and fixed in a case, a method in which a dent or a partition is provided in a substrate or a sealing plate, and CaH ₂ , SrH ₂ , BaH ₂ , and AlLiH ₄ are arranged there. . Further, it may be arranged as a thin film or a thick film in an airtight case by screen printing or reactive sputtering. At this time, the thickness of the film is preferably about 0.1 to 100 μm.

Next, the organic EL structure constituting the organic EL device of the present invention will be described. The organic EL structure of the present invention has a hole injection electrode, an electron injection electrode, and one or more organic layers provided between these electrodes on a substrate. The organic layer may have at least one electron injection layer and at least one light emitting layer, an electron injection electrode thereon, and a protective electrode as the uppermost layer. Note that the electron injection layer may not be provided.

First, the electron injection electrode will be described.

As a constituent material of the electron injection electrode, a substance having a low work function for effectively injecting electrons, that is, an alkali metal (Li, Na, K, Rb, Cs) or an alkaline earth metal (Mg, Ca, Sr, Ba). In particular, since high luminance can be obtained by using Li,
preferable. These may be used alone as a metal element,
It is preferable to use any of these alloys, these oxides and these fluorides. These oxides,
Fluoride is usually present in its stoichiometric composition,
The amount and F amount may be slightly deviated. These are 1
Seeds may be used, or two or more kinds may be used. The alloy system is not particularly limited, but for example, Ag · Mg (A
g: 1 to 20 at%), Al.Li (Li: 0.3 to 14)
at%), In.Mg (Mg: 50-80at%), Al.
Ca (Ca: 5 to 20 at%) and the like are preferable.

As the electron injection electrode, among these,
In particular, Al.Li (Li: 0.4 to 6.5 (however, 6.5
At%) or (Li: 6.5 to 14 at%),
Li ₂ O and LiF are preferred.

As an electron injection electrode, a hydride of an alkali metal (LiH, NaH, KH, RbH, Cs
H), alkaline earth metals (MgH ₂ , CaH ₂ , Sr
H ₂ , BaH ₂ ), preferably LiH
It is also preferable to use

As will be described later, when the organic layer contains at least one of an alkali metal and an alkaline earth metal, those described above are also preferably used as an electron injection electrode. , Ce, Al, A
g, In, Sn, Zn, Zr, Er, Eu, Ga, H
f, Nd, Rb, Sc, Sm, Ta, Y, Yb or other metal element alone, or HfC, LaB ₆ , MoC, Nb
C, PbS, TaC, ThC, ThO ₂ , ThS, Ti
C, TiN, UC, UN, UO ₂ , W ₂ C, Y ₂ O ₃ , Zr
Compounds such as C, ZrN and ZrO ₂ may be used. In order to improve the stability, it is preferable to use a two-component or three-component alloy system containing a metal element. As alloys, other than the above, for example, Al.In (I
n: 1 to 10 at%), and aluminum alloys such as Al.R (R represents a rare earth element containing Y and Sc) are preferable. Among these, in particular, Al alone or Al.R (R:
Aluminum alloys such as 0.1 to 25 (particularly 0.5 to 20 at%) are preferable because they hardly generate compressive stress. These work functions are 4.5 eV or less, and metals and alloys having a work function of 4.0 eV or less are particularly preferable.

The thickness of the electron injecting electrode is 1 nm or less, especially 0.1 nm.
5 nm or less is preferable. Conventionally, it has been considered that the film thickness is preferably 4 nm or more in order to form a uniform film. However, the effect of the present invention that a constant luminance can be obtained for a long time is obtained when the film thickness of the electron injection electrode is 1 nm or less. Is obtained. The lower limit is usually about 0.1 nm. The electron injection electrode does not need to be present as a film, and particles of alkali metal and / or alkaline earth metal may be present in the form of islands on the surface (interface) of the organic layer.

The electron injection electrode of the present invention is usually in an amorphous state or has a crystal grain size of 100 nm or less.

The electron injection electrode is formed by vapor deposition, sputtering or the like.

When the electron injecting electrode is formed by a vapor deposition method, the conditions of vacuum vapor deposition are not particularly limited, but it is preferable that the degree of vacuum is 10 ⁻⁴ Pa or less and the vapor deposition rate is about 0.01 to 1 nm / 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.

When the electron injection electrode is formed by the sputtering method, the pressure of the sputtering gas during the sputtering is 0.1 to 5 Pa
Is preferable. Further, by changing the pressure of the sputtering gas within the above range during the film formation, an electron injection electrode having a concentration gradient can be easily obtained. Further, the product of the film forming gas pressure and the distance between the substrate targets is 20 to 65 Pa ·
It is preferable that the film formation conditions satisfy cm.

The sputtering gas may be an inert gas such as Ar used in a normal sputtering apparatus, or a reactive sputtering such as N ₂ , H ₂ , O ₂ , C ₂ H ₄ , NH _3, etc. Neutral gas can be used.

As a sputtering method, a film may be formed by using a suitable sputtering method from a high frequency sputtering method using an RF power source, a DC sputtering method, and the like. The power of the sputtering apparatus is preferably 0.1 to 10 W / cm by DC sputtering.
^2, in the range of 1 to 10 W / cm ² in RF sputtering. The film formation rate is 5 to 100 nm / min, especially 10 to 50 nm.
The range of nm / min is preferred.

Next, the organic layer provided in the organic EL structure of the present invention will be described.

The light emitting layer has a function of transporting holes (holes) and electrons, and a function of generating excitons by recombination of holes and electrons. It is preferable to use a relatively electronically neutral compound for the light emitting layer.

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, tetraarylethene derivatives described in JP-A-8-12969, and the like 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 0.01 to 20% by weight, and more preferably 0.1 to 20% by weight.
It is preferably 1 to 15% by weight. 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.

As the host substance, a quinolinolato complex is preferable, and an aluminum complex having 8-quinolinol or a derivative thereof as a ligand is preferable. 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 its derivative, 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
Also preferred are a phenylanthracene derivative of No. -12600 and a tetraarylethene derivative of JP-A-8-12969.

The light emitting layer may also serve as an electron injection layer. In such a case, tris (8-quinolinolato)
It is preferable to use 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 dopant in such a mixed layer is 0.01 to 20% by weight, more preferably 0.1 to 20% by weight, based on the total amount of the hole injecting and transporting compound and the electron injecting and transporting compound.
It is preferable that the content be 1 to 15% by weight.

In the mixed layer, a carrier hopping conduction path is formed, so that each carrier moves in a material having a polar advantage, and carrier injection of 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 and transporting compounds used in the mixed layer include, for example, JP-A-63-295695, JP-A-2-191694, JP-A-3-792, and JP-A-5-234681. JP-A-5-239
455, JP-A-5-299174, JP-A-7-126225, JP-A-7-126226, JP-A-8-100172, EP065095
Various organic compounds described in 5A1 and the like can be used. For example, a tetraarylbendicine compound (triaryldiamine or triphenyldiamine:
TPD), aromatic tertiary amines, hydrazone derivatives, carbazole derivatives, triazole derivatives, imidazole derivatives, oxadiazole derivatives having an amino group, polythiophene, and the like. These compounds may be used alone or in combination of two or more.

As the compound capable of injecting and transporting holes, an amine derivative having strong fluorescence, for example, a triphenyldiamine derivative, a styrylamine derivative, or an amine derivative having an aromatic condensed ring is preferably used.

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 a phenylanthracene derivative or a tetraarylethene derivative. An oxadiazole derivative, a perylene derivative, a pyridine derivative, a pyrimidine derivative, a quinoxaline derivative, a diphenylquinone derivative, a nitro-substituted fluorene derivative, or the like can be used. These compounds may be used alone or in combination of two or more.

The mixing ratio in this case depends on the respective carrier mobility and carrier concentration. In general, the weight ratio of the compound of the hole injection / transport compound / the electron injection / transport compound is from 1/99 to 99/99. 1, more preferably 10/9
0 to 90/10, particularly preferably 20/80 to 80/2
It is preferable to set the value to about 0.

The thickness of the mixed layer is preferably not less than the thickness of 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 for 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 the same or very close, the mixed layers are previously mixed 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.

Particularly preferred as the light-emitting layer are an aluminum complex having 8-quinolinol or a derivative thereof as a ligand, and a mixed layer in which a tetraarylbendicine compound is doped with a fluorescent substance such as rubrene or coumarin. The mixing ratio of the aluminum complex having 8-quinolinol or a derivative thereof as a ligand and the tetraarylbendicine compound is preferably in the above range. The doping fluorescent substance such as rubrene,
Preferably it is 0.01 to 20 mol%.

The hole injecting / transporting layer has a function of facilitating the injection of holes from the hole injecting electrode, a function of stably transporting holes, and a function of hindering electrons.
The electron injection layer has a function of facilitating injection of electrons from the electron injection electrode, a function of stably transporting electrons, and a function of preventing holes. These layers increase and confine holes and electrons injected into the light emitting layer, optimize the recombination region, and improve luminous efficiency.

The thickness of the hole injecting and transporting layer and the thickness of the electron injecting layer are not particularly limited and vary depending on the forming method, but are usually about 5 to 500 nm, especially about 10 to 3 nm.
It is preferably set to 00 nm.

The thickness of the hole injecting and transporting layer and the thickness of the electron injecting layer depend on the design of the recombination / light emitting region, but may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times. When the hole or electron injection layer and the transport layer are separated from each other, it is preferable that the injection layer has a thickness of 1 nm or more and the transport layer has a thickness of 1 nm or more. At this time, the upper limit of the thickness of the injection layer and the transport layer is usually about 500 nm for the injection layer and about 500 nm for the transport layer. For such a film thickness, the injection / transport layer is
The same applies when providing layers.

The hole injecting and transporting layer is described, for example, in JP-A-63-295695 and JP-A-2-19169.
4, JP-A-3-792, JP-A-5-234
681, JP-A-5-239455, JP-A-5-299174, JP-A-7-126225, JP-A-7-126226, JP-A-8-100
Various organic compounds described in JP-A-172, 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.

When the hole injecting and transporting layer is provided separately as a hole injecting and transporting layer, a preferred combination can be selected from the compounds for the hole injecting and transporting layer. At this time, it is preferable to laminate the compounds in order from the hole injecting electrode (ITO or the like) with the smallest ionization potential. Further, it is preferable to use a compound having a good thin film property on the surface of the hole injection electrode. Such a stacking order is the same when two or more hole injection transport layers are provided. With such a stacking order, the driving voltage is reduced, and the occurrence of current leakage and the occurrence and growth of dark spots can be prevented. In addition, in the case of forming an element, since a thin film of about 1 to 10 nm can be made uniform and pinhole-free because evaporation is used,
Even if a compound having a small ionization potential and having absorption in the visible region is used for the hole injection layer, it is possible to prevent a change in the color tone of the emission color and a decrease in efficiency due to reabsorption. The hole injecting and transporting layer can be formed by vapor deposition of the above compound in the same manner as the light emitting layer and the like.

The electron-injecting layer provided as necessary may include tris (8-quinolinolato) aluminum (Al
q3) and other quinoline derivatives such as organometallic complexes having 8-quinolinol or a derivative thereof as a ligand, oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, etc. Can be used. The electron injection layer may also serve as a light emitting layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. The electron injection layer may be formed by vapor deposition or the like, similarly to the light emitting layer.

The electron injection layer may be laminated in two layers, and in that case, a preferable combination can be selected from the compounds for the electron injection layer. At this time, it is preferable to stack the compounds in descending order of the electron affinity value from the electron injection electrode side. Such a stacking order is the same when two or more electron injection layers are provided.

In the organic EL device of the present invention, at least one organic layer in contact with the electron injection electrode has an alkali metal (Li,
Na, K, Rb, Cs), alkaline earth metals (Mg, C
a, Sr, and Ba). In particular, it is preferable to contain Li because high luminance can be obtained. As described above, a high brightness can be obtained by doping a metal having a small work function into an organic layer in contact with the electron injection electrode and interacting (coordinating) with an organic substance. The organic layer containing an alkali metal and / or an alkaline earth metal is usually an electron injection layer and / or a light emitting layer, preferably an electron injection layer.

The content of the alkali metal and / or alkaline earth metal contained in the electron injection layer is 0.1 to 10 wt.
%, Particularly preferably 1 to 3% by weight. If the content is more or less than this, the luminance tends to fluctuate. On the other hand, if the content is small, high luminance cannot be obtained.

The concentration of the alkali metal and / or the alkaline earth metal may be uniform, but may be present on the electron injection electrode side, and may have a concentration gradient. In particular,
1-3 wt% in the range of 0-50 nm from the interface of the electron injection electrode
It is preferred to contain.

The alkali metal and / or alkaline earth metal in the organic layer usually exists in an atomic state, but may form a cluster of several atoms.

The organic layer containing an alkali metal and / or an alkaline earth metal can be formed by co-evaporation of an organic substance and an alkali metal and / or an alkaline earth metal.

For forming the hole injection transport layer, the light emitting layer and the electron injection transport layer, a uniform thin film can be formed.
It is preferable to use a vacuum deposition method. When vacuum deposition is used, the amorphous state or the crystal grain size is 0.1 μm
The following homogeneous thin film 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.
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 growth and generation 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 hole injecting electrode usually has a structure in which light emitted from the substrate side is taken out, so that a transparent electrode is preferable, and ITO (tin-doped indium oxide), IZO
(Zinc-doped indium oxide), ZnO, SnO ₂ , I
n ₂ O _{3 and the} like, preferably ITO, IZO
Is preferred. The mixing ratio of SnO ₂ to In ₂ O ₃ is:
1-20 wt% is preferable, and 5-12 wt% is more preferable.
% Is preferred. In ₂ O ₃ The mixing ratio of ZnO to
1-20 wt% is preferable, and 5-12 wt% is more preferable.
% Is preferred. In addition, Sn, Ti, Pb, and the like may be contained in the form of oxides in an amount of 1% by weight or less in terms of oxides.

The hole injection electrode can be formed by a vapor deposition method or the like, but is preferably formed by a sputtering method. When a sputtering method is used for forming the ITO or IZO electrode, a target in which Sn ₂ or ZnO is doped into In ₂ O ₃ is preferably used. When the ITO transparent electrode is formed by the sputtering method, the luminescence luminance has less change with time than that formed by the vapor deposition. DC sputtering is preferable as the sputtering method, and the input power is 0.1 to 4
A range of W / cm ² is preferred. In particular, the power of the DC sputtering apparatus is preferably in the range of 0.1 to 10 W / cm ² , particularly preferably in the range of 0.2 to 5 W / cm ² . Further, the film formation rate is preferably in the range of 2 to 100 nm / min, particularly preferably in the range of 5 to 50 nm / min.

The sputtering gas is not particularly limited, and an inert gas such as Ar, He, Ne, Kr, and Xe, or a mixed gas thereof may be used. As the pressure at the time of sputtering such a sputtering gas,
Usually, it may be about 0.1 to 20 Pa.

The thickness of the hole injecting electrode may be a certain value or more that can sufficiently inject holes, and is usually 5 to 50.
0 nm, preferably in the range of 10 to 300 nm.

In the organic EL device of the present invention, a protective electrode may be provided on the electron injection electrode, that is, on the side opposite to the organic layer.
By providing the protective electrode, the electron injection electrode is protected from the outside air, moisture, and the like, the deterioration of the constituent thin film is prevented, the electron injection efficiency is stabilized, and the element life is dramatically improved. Also,
This protection electrode has a very low resistance, and also has a function as a wiring electrode when the resistance of the electron injection electrode is high. This protective electrode is made of Al, Al and a transition metal (except for Ti
), Ti or titanium nitride (TiN), and when these are used alone, at least Al: 90-1
00at%, Ti: 90-100at%, TiN: 90-1
It is preferable to contain about 00 mol%. Also,
When two or more kinds are used, the mixing ratio is arbitrary, but Al and T
In the mixing of i, the content of Ti is preferably 10 at% or less. Further, a layer containing these alone may be laminated. In particular, when Al, Al and transition metals are used as wiring electrodes described later, good effects are obtained, and TiN has high corrosion resistance and a large effect as a sealing film. TiN is
It may deviate from the stoichiometric composition by about 10%.
In addition, alloys of Al and transition metals include transition metals, especially Sc, Nb, Zr, Hf, Nd, Ta, Cu, Si, C
Preferably, the total of r, Mo, Mn, Ni, Pd, Pt, W, etc. may contain 10 at% or less, more preferably 5 at% or less, particularly preferably 2 at% or less. The smaller the content of the transition metal, the lower the thin film resistance when functioning as a wiring material.

The thickness of the protective 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 to prevent entry of moisture, oxygen or an organic solvent. Particularly preferably, 1
The range of 00 to 1000 nm is preferred. If the protective electrode layer is too thin, the effect of the present invention cannot be obtained, and the step coverage of the protective electrode layer will be low, and the connection with the terminal electrode will not be sufficient. On the other hand, if the protective electrode layer is too thick, the stress of the protective electrode layer increases, so that the growth rate of dark spots increases. The thickness when functioning as a wiring electrode is generally 100 to 500 nm when the film resistance is high because the film thickness of the electron injection electrode is small.
Degree, 1 when functioning as other wiring electrode
It is about 00 to 300 nm.

The total thickness of the electron injecting electrode and the protective electrode is not particularly limited, but is usually 50 to 1000.
It may be set to about nm.

After forming the electrode, in addition to the protective electrode, S
inorganic materials iO _X such as Teflon, a protective film may be formed using an organic material such as fluorocarbon polymers containing chlorine. The protective film may be transparent or opaque, and the thickness of the protective film is about 50 to 1200 nm. The protective film may be formed by a general sputtering method, an evaporation method, a PECVD method, or the like, in addition to the reactive sputtering method.

Next, the organic EL device of the present invention will be described. In the organic EL device of the present invention, an organic EL structure is stacked on a substrate, and a connection between the sealing plate and a sealing plate arranged so as to have a predetermined gap on the organic EL structure is provided. A spacer for maintaining the sealing plate at a predetermined distance from the substrate, and a sealing adhesive for fixing the sealing plate and sealing the organic EL structure. Then, CaH ₂ , SrH ₂ , BaH ₂ , a desiccant,
AlLiH ₄ is arranged in a non-contact state with the organic EL structure, and a sealing gas is sealed.

The sealing gas in the airtight case is Ar, He,
Inert gas such as N ₂ is used. However, C desiccant
When aH ₂ , SrH ₂ , or BaH ₂ is used, N ₂ is preferable. However, when AlLiH ₄ is used as a desiccant, N ₂ cannot be used as a sealing gas at a high temperature. Therefore, it is preferable to use Ar. The moisture content of this sealing gas is 1
It is preferably at most 00 ppm, more preferably at most 10 ppm, particularly preferably at most 1 ppm. Although there is no particular lower limit for this water content, it is usually about 0.1 ppm. By using such a sealing gas, deterioration due to a chemical reaction between the hole injection electrode, the organic layer, the electron injection electrode, or the interface thereof and moisture or the like of the organic EL structure is suppressed, and the initial performance is increased. Can be maintained for a period.

Examples of the material for the sealing plate include transparent or translucent materials such as glass, quartz, and resin, and more preferably glass. As such a glass material,
For example, a glass composition such as soda-lime glass, lead-alkali glass, borosilicate glass, aluminosilicate glass, and silica glass is preferable. Further, the sealing plate is preferably flat. Dust and the like may be provided on the sealing plate, and a desiccant may be provided therein. However, since providing the dust increases costs, it is preferable to use inexpensive flat glass. As the plate making method, a roll-out method, a download method, a fusion method, a float method and the like are preferable. As a surface treatment method for the glass material, a polishing treatment, a SiO ₂ barrier coat treatment, or the like is preferable. Among them, soda-lime glass produced by a float method and having no surface treatment can be used at a low cost, and is preferable. As the sealing plate, other than a glass plate, a metal plate, a plastic plate, or the like can be used.

The means for adjusting the height of the sealing plate is not particularly limited, but it is preferable to use a spacer. By using spacers, it is inexpensive,
A desired height can be easily obtained. Examples of the material of the spacer include resin beads, silica beads, glass beads, and glass fibers, and glass beads are particularly preferable. Further, the thickness is usually preferably about 1 to 500 μm, more preferably about 1 to 200 μm, particularly about 1 to 20 μm, or about 100 to 200 μm.

When a concave portion 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 1 to 20 μm is preferable. The amount of adhesive applied depends on the size of the spacer used, etc.
Usually 1 to 100 mg / cm ² , more preferably 1 to 10 mg / cm ²
It is preferably about cm ² .

The spacer is preferably used together with a sealing adhesive. When used together with the sealing adhesive, the fixing of the spacer and the sealing can be performed simultaneously. 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. Note that the adhesive may also serve as the spacer, or the spacer may be formed integrally with the sealing plate.

As the adhesive, a cationically curable ultraviolet-curable epoxy resin adhesive is preferably used. The glass transition temperature of each layer constituting material of the organic EL laminated structure portion is 140 ° C. or less, particularly about 80 to 100 ° C. Therefore, when a normal thermosetting adhesive is used, the curing temperature is about 140 to 180 ° C., so that the organic EL structure is softened when the adhesive is cured, and the characteristics are deteriorated. I will. On the other hand, in the case of an ultraviolet curable adhesive, such softening of the organic EL structure does not occur. However, currently used ultraviolet curable adhesives are acrylic, so that the acrylic monomer in the components volatilizes during curing, which adversely affects each constituent material of the organic EL structure, The characteristics are degraded. Therefore, in the present invention, it is preferable to use the above-mentioned cationically-curable ultraviolet-curable epoxy resin adhesive, which does not have the above-described problems or is an extremely small amount of adhesive.

[0098] In some cases, a commercially available ultraviolet-curable epoxy resin adhesive includes an ultraviolet-heat-curable epoxy resin adhesive. In this case, the radical-curing type acrylic resin and the heat-curing type epoxy resin are often mixed or modified, and the above-mentioned problem of volatilization of the acrylic monomer of the acrylic resin and curing of the thermosetting type epoxy resin. Since the problem of temperature has not been solved, it is not preferable as an adhesive used for the organic EL device of the present invention.

The cationically curable UV-curable epoxy resin adhesive includes a Lewis acid salt type curing agent which releases a Lewis acid catalyst by photolysis by irradiation with light such as ultraviolet rays as a main curing agent, and is generated by light irradiation. This type of adhesive is a type in which an epoxy resin, the main component of which is a Lewis acid as a catalyst, is polymerized and cured by a cationic polymerization type reaction mechanism.

The epoxy resin which is the main component of the adhesive includes an epoxidized olefin resin, an alicyclic epoxy resin, a novolak epoxy resin and the like. Further, as the curing agent, Lewis acid salt of aromatic diazonium,
Examples thereof include Lewis acid salts of diallyliodonium, Lewis acid salts of triallylsulfonium, Lewis acid salts of triallyl selenium, and the like.

The height of the organic EL element structure to be formed is
Although not particularly limited, usually 100 to 1000
nm, particularly preferably in the range of 300 to 800 nm. Further, the distance from the organic EL element structure deposition surface of the substrate to the lower end surface of the sealing plate is preferably 200 μm or less, particularly 80 μm or less.
The range is preferably about 150 μm.

Since the organic EL element is extremely weak to moisture, the sealing plate is fixed tightly and the sealing substance is sealed with dry N ₂ , Ar,
It is preferable to carry out in an atmosphere of an inert gas such as He. Desiccants CaH ₂ , SrH ₂ , BaH ₂ , AlLiH ₄
Since it is easy to react with water, it is preferable to use one that is sufficiently dried to reduce the amount of water in the sealed space.
It is preferable that the steps from lamination of the organic EL structure, placement of the desiccant, and sealing be performed in-process without being exposed to an external system.

As a substrate material, a transparent or translucent material such as glass, quartz, or resin is used in the case of taking out light emitted from the substrate side. In the case of reverse lamination, the substrate may be transparent or opaque, and when opaque, ceramics or the like may be used.

Further, the emission 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.

When 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 a color filter.

The fluorescence conversion filter film absorbs EL light and emits light from the phosphor in the fluorescence conversion film to convert the color of the emitted light. 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, such as rhodamine-based compounds, perylene-based compounds, cyanine-based compounds, phthalocyanine-based compounds (including subphthalocyanines, etc.), naphthalimide-based compounds, condensed-ring hydrocarbon-based compounds, and condensed heterocyclic-based compounds Compounds, styryl compounds,
A coumarin compound or the like may be used.

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

The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but need not be used 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 generally used as a DC drive type EL device, but it can be AC drive or pulse drive. The applied voltage is usually 2 to 2
It is about 0V.

[0113]

EXAMPLES Next, the present invention will be described more specifically with reference to examples.

Example 1 A simple matrix light emitting device was manufactured as follows.

On a Corning 7059 glass substrate,
ITO transparent electrode (hole injection electrode) is 64
× 256 dot pixels (280 × 280μ per pixel)
m) was formed and patterned. And
The substrate on which the hole injection electrode was formed was subjected to ultrasonic cleaning using a neutral detergent, acetone and ethanol, pulled up from boiling ethanol and dried. Then, the surface is UV / O ₃
After cleaning, fix it on the substrate holder of the vacuum evaporation device,
The pressure in the tank was reduced to 1 × 10 ⁻⁴ Pa or less. And 4,
4 ', 4 "-tris (-N- (3-methylphenyl)-
N-phenylamino) triphenylamine (m-MTD
ATA) was deposited at a deposition rate of 0.2 nm / sec. To a thickness of 40 nm to form a hole injection layer. Next, N, N'-diphenyl-N, N'-m-tolyl-4,4'-diamino-1,
1′-biphenyl (hereinafter, TPD) is deposited at a deposition rate of 0.2 nm.
/ Sec. To form a hole transport layer with a thickness of 35 nm.
Next, tris (8-quinolinolato) aluminum (hereinafter, Alq3) was deposited at a deposition rate of 0.2 nm / sec to a thickness of 50 nm to form a light emitting layer. Next, by DC sputtering, an Al layer having a Li concentration of 7.3 at% was formed to a thickness of 0.5 nm.
An i-alloy film was formed to form an electron injection electrode. At this time,
The sputtering pressure was 1.0 Pa, the sputtering gas was Ar, the input power was 100 W, the size of the target was 4 inches in diameter, and the distance between the substrate and the target was 90 mm. Then, by a DC sputtering method using an Al target, A
A protective electrode was formed to a thickness of 200 nm.

The substrate on which the organic EL structure is laminated is
It was transferred to a glove box through which N ₂ gas was passed. And CaH ₂ particles are placed in a net as a desiccant,
It was fixed, and 100 mg of an ultraviolet-curable epoxy resin adhesive (30Y296D manufactured by ThreeBond) was applied to the glass substrate in an uncured state. And 100 μm as a sealing plate
Another 7059 glass manufactured by Corning Co., Ltd. which was processed so as to provide a hermetic space of a degree, was pressed with a pressure of 3 kg / cm ² while sliding the substrates together, and a thin adhesive was applied between the glass substrate and the sealing plate. A layer was formed. At this time, 1 μm of a 7 μm spacer was dispersed in the adhesive so that the thickness of the adhesive was 7 μm. Then, UV light was irradiated to cure the adhesive, thereby obtaining an organic EL device. The amount of desiccant is
It was 0.01 mg / mm ³ per 1 mm ³ of space in the airtight case.

A DC voltage was applied to the obtained organic EL device in an air atmosphere, and at a temperature of 70 ° C. under an acceleration condition, 10 mA /
Continuous driving was performed at a constant current density of cm ² , and a relative change in luminance and an increase in a non-light-emitting area were measured.

This organic EL device had a relative luminance of 0.95 to 1.1 after driving for 600 hours. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less. The relative luminance was calculated as the luminance value when the initial luminance was set to 1, that is, as the luminance after driving / initial luminance. The non-light-emitting area ratio was calculated as (non-light-emitting area) / (pixel area) × 100 (%).

<Example 2> An organic EL device was obtained in the same manner as in Example 1 except that the same amount of SrH ₂ was used instead of CaH ₂ as a drying agent, and was evaluated in the same manner as in Example 1.

The relative luminance of this organic EL device after driving for 600 hours was 0.95 to 1.1. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less.

Example 3 An organic EL was prepared in the same manner as in Example 1 except that the same amount of AlLiH ₄ was used instead of CaH ₂ as a drying agent, and Ar gas was used instead of N ₂ gas as a sealing gas. An element was obtained and evaluated in the same manner as in Example 1.

The relative luminance of this organic EL device after driving for 600 hours was 0.95 to 1.1. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less.

<Example 4> An organic EL device was obtained in the same manner as in Example 1 except that the same amount of BaH ₂ was used instead of CaH ₂ as a drying agent. With this organic EL element, the same effects as in Example 1 were obtained.

<Example 5> [0124] Organic E was prepared in the same manner as in Example 1 except that the electron injection electrode was changed to Li ₂ O instead of AlLi.
An L element was obtained and evaluated in the same manner as in Example 1.

The relative luminance of this organic EL device after driving for 600 hours was 0.95 to 1.1. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less.

Example 6 An organic EL device was manufactured in the same manner as in Example 1 except that the electron injection electrode was changed to LiF instead of AlLi.
An element was obtained and evaluated in the same manner as in Example 1.

This organic EL device also had a relative luminance after driving for 600 hours of 0.95 to 1.1. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less.

<Comparative Example 1> An organic EL device was obtained in the same manner as in Example 1 except that the same amount of zeolite was used instead of CaH ₂ as a drying agent, and evaluated in the same manner as in Example 1.

This organic EL device had a relative luminance after driving for 100 hours of 1.5 or more, and a relative luminance after driving for 300 hours of 2 or more. The non-light-emitting area ratio after driving for 100 hours is 5% or more, and the non-light-emitting area ratio after driving for 250 hours is 10%.
That was all. In 400 hours, the non-light emitting area ratio is 20% or more,
The non-light-emitting area ratio became 30% or more in 600 hours.

Comparative Example 2 An organic EL device was obtained in the same manner as in Example 1 except that the thickness of the electron injection electrode was changed to 4 nm, and evaluated in the same manner as in Example 1.

Although the organic EL device had a non-light-emitting area ratio of 1% or less after driving for 1000 hours, the relative luminance after driving for 200 hours was 0.8 or less, and the relative luminance after driving for 400 hours was 0.5. Hereinafter, the relative luminance after driving for 600 hours was 0.4 or less.

Comparative Example 3 An organic EL device was obtained in the same manner as in Example 1 except that the same amount of BaO was used instead of CaH ₂ as a drying agent, and was evaluated in the same manner as in Example 1.

The organic EL element stopped emitting light after being driven for 180 hours, and did not function as an element.

<Example 7> As in Example 1, an ITO transparent electrode, a hole injection layer (m-MTDATA),
After forming a hole transport layer (TPD) and a light emitting layer (Alq3), Li and Alq3 are co-deposited to a thickness of 40 nm to form an electron injection layer (Li concentration 1.5 wt%), and an Al electrode (cathode). Was formed to a thickness of 200 nm, and the organic EL structure was sealed in the same manner as in Example 1 to obtain an organic EL device.

This organic EL element also had a relative luminance of 0.95 to 1.1 after driving for 600 hours. The non-light-emitting area ratio after driving for 400 hours was 1% or less, and the non-light-emitting area ratio after driving for 600 hours was 3% or less.

Further, a DC voltage was applied to the organic EL devices of Examples 1 to 7 and Comparative Examples 1 to 3 under acceleration conditions of a temperature of 60 ° C. and a humidity of 95% RH, and a constant current density of 10 mA / cm ^2. 10
The device was continuously driven for 00 hours, and the relative change in luminance and the expansion of the non-light-emitting area were measured. The organic EL device of the present invention showed a very small change in luminance and an increase in the non-light-emitting area, even under high humidity, as compared with the comparative example.

[0137]

As described above, according to the present invention, it can be easily manufactured, the influence of moisture and the like is eliminated as much as possible, deterioration over time, in particular, enlargement of non-light-emitting area, change in luminance is small, and initial performance is maintained for a long time. It is possible to provide an organic EL device having a long service life.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Michio Arai 1-1-13 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Hiroyuki Endo 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK (72) Inventor Mayuki Kawashima 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Toshio Hayakawa 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation F term (reference) 3K007 AB13 AB18 BB04 BB05 CA01 CB01 DA01 DB03 EB00 FA02

Claims (11)

[Claims] An organic EL structure including a hole injection electrode, an electron injection electrode, and an organic layer including one or more light emitting layers provided between these electrodes is housed in an airtight case, In an airtight case, at least one of calcium hydride, strontium hydride, barium hydride and lithium aluminum hydride is disposed, and the electron injection electrode is provided with at least one of an alkali metal and an alkaline earth metal. Organic EL device containing. 2. The organic EL device according to claim 1, wherein said electron injection electrode has a thickness of 1 nm or less. 3. The organic EL device according to claim 1, wherein at least one of the organic layers contains at least one of an alkali metal and an alkaline earth metal. 4. An organic EL structure having a hole injection electrode, an electron injection electrode, and an organic layer including one or more light emitting layers provided between these electrodes is housed in an airtight case. At least one of calcium hydride, strontium hydride, barium hydride and lithium aluminum hydride is disposed in the airtight case, and at least one of the organic layers is any one of an alkali metal and an alkaline earth metal. Organic E containing at least one kind
L element. 5. The method according to claim 1, wherein the organic layer has an electron injection layer between the electron injection electrode and the light emitting layer, and the electron injection layer contains at least one of an alkali metal and an alkaline earth metal. Item 3. The organic EL device according to item 3 or 4. 6. The electron injection electrode contains one or more of an alkali metal alloy, an oxide thereof, a fluoride thereof, an alkaline earth metal alloy, an oxide thereof and a fluoride thereof. Claim 1, 2, 3, or 5
Any one of the organic EL devices. 7. The organic EL device according to claim 1, wherein the electron injection electrode and / or the organic layer contains lithium. 8. The organic EL device according to claim 7, wherein said electron injection electrode contains at least one of an aluminum lithium alloy, lithium oxide and lithium fluoride. 9. The organic EL device according to claim 3, wherein the content of alkali metal and / or alkaline earth metal in the organic layer is 0.1 to 10% by weight. 10. The airtight case comprises: a substrate on which the organic EL structure is laminated; a sealing plate provided with a predetermined gap on the organic EL structure; 10. A sealing adhesive which is in close contact with the substrate.
Any one of the organic EL devices. 11. The organic E according to claim 10, wherein said void is filled with nitrogen, and calcium hydride and / or strontium hydride is disposed in said airtight case.
L element.