JP2531857B2 - Organic electroluminescent device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electroluminescence device such as an electroluminescence element or an electroluminescence lamp, and more particularly to an organic electroluminescence device.

[Prior Art] Electroluminescence devices such as electroluminescence elements and electroluminescence lamps (hereinafter collectively referred to as EL devices) have high visibility because they are self-luminous, and shock resistance because they are completely solid-state devices. Excellent in handling and easy to handle. For this reason, research and development and practical application are being promoted as pixels for graphic displays, pixels for television image display devices, or surface light sources.

Such EL devices can be roughly classified into inorganic EL devices and organic EL devices.

In an inorganic EL device, for example, two light-emitting layers in which an inorganic fluorescent substance in which an activator such as Mn is added to ZnS are dispersed in a transparent dielectric are opposed to each other (the light-emitting surface side electrode is a transparent electrode). ) Dispersed type in which a laminated structure interposed between them is formed on a transparent substrate, or a two-layer transparent inorganic insulating layer made of Si ₃ N ₄ , Al ₂ O ₃ or the like having a light emitting layer made of an inorganic fluorescent substance. There is a three-layer thin film type in which a laminated structure which is sealed by a layer (dielectric layer) and is interposed between two electrodes (the electrode on the light emitting surface side is a transparent electrode) is formed on a transparent substrate. These inorganic EL devices (including LEDs) are usually provided with a glass plate via silicone oil, a sealing film made of resin or a protective film made of glass for the purpose of preventing moisture or mechanical protection. It is provided.

In such an inorganic EL device, an electric field is applied to the light emitting layer to directly excite the active center by the electric field, or the active center is excited by electrons accelerated by the electric field, and the excited active center is in the ground state. It utilizes the light emission that occurs when returning. Therefore, the inorganic EL device has a drawback that a high voltage such as 200 V is required as a driving voltage, and that the driving method becomes complicated with the application of the high voltage.

On the other hand, an organic EL device includes a light emitting layer made of a fluorescent organic solid such as anthracene and a hole injection layer made of a triphenylamine derivative, or an electron injection layer made of a light emitting layer and a perylene derivative, or a hole injection layer. In general, a laminated structure in which a light emitting layer and an electron injection layer are interposed between two electrodes (the light emitting surface side electrode is a transparent electrode) is formed on a substrate.

Such an organic EL device utilizes the light emission generated when the electrons and holes injected into the light emitting layer are recombined. Therefore, the organic EL device has the advantage that it can be driven at a low voltage of 4.5 V and has a quick response by reducing the thickness of the light emitting layer, and the EL device with high brightness because the brightness is proportional to the injection current. It has the advantage of being able to obtain Further, by changing the kind of the fluorescent organic solid used as the light emitting layer, light emission is obtained in all colors of blue, green, yellow and red visible regions.

Since the organic EL device has such advantages, in particular, the advantage that it can be driven at a low voltage, research and development are currently underway as various devices.

[Problems to be Solved by the Invention] However, a fluorescent organic solid, which is a material for a light emitting layer of an organic EL device, has low mechanical strength and is vulnerable to heat, solvent, moisture, oxygen and the like. When this organic EL device is driven in a state where a part of the light emitting layer is exposed to the atmosphere, the characteristics of the light emitting layer are rapidly deteriorated, which causes a problem that the life of the device is short.

The ingress of water and oxygen into the light emitting layer of the organic EL device is caused by the laminated structure of the organic EL device, that is, 2
It is possible to prevent this by covering a laminated structure in which at least a light emitting layer is interposed between two electrodes with a protective film made of an appropriate substance. The appropriate substance here is
From the viewpoint of preventing the deterioration of the characteristics of the light emitting layer, it is excellent in moisture resistance and inferior in oxygen permeability, and there is no particular limitation on color.
When the surface on which the protective film is provided is used as a light emitting surface, it needs to be transparent and is a substance having excellent electric insulation.

Materials that meet these conditions include Si ₃ N ₄ and Si
There are nitrides or oxides such as O ₂ and Al ₂ O _3, and a protective film made of these substances can be formed by a physical vapor deposition method or a chemical vapor deposition method. Since the fluorescent organic solid, which is the material of (1), has a low mechanical and thermal strength, the fluorescent organic solid is physically damaged by vapor deposition, and it becomes impossible to obtain an organic EL device having high brightness and long life. Further, since the coefficient of thermal expansion of the protective film made of the above-mentioned nitride or oxide is greatly different from the coefficient of thermal expansion of the fluorescent organic solid, when the laminated structure is coated with such a protective film, the thermal Due to the difference in expansion coefficient, the protective film is cracked, and a sufficient protective effect cannot be obtained.

When the laminated structure is covered with a sealing film made of an appropriate resin or a protective film made of glass, the light emitting layer may be heated by the solvent used when these films are provided or the heat when these films are provided. Since the fluorescent organic solid, which is the material of (3), is denatured, it becomes impossible to obtain an organic EL device with high brightness and long life. It should be noted that organic used as pixels, etc.
A resin thin film applicable to EL devices, which satisfies the above-mentioned conditions, has not been developed so far.

As described above, the fluorescent organic solid, which is the material of the light emitting layer in the organic EL device, is weak against water and oxygen, and has low mechanical strength and is weak against heat or solvent. There is a problem in that moisture and oxygen cannot be prevented from entering the light emitting layer without deteriorating the characteristics of the solid and the life of the device is short. Therefore, the object of the present invention can be used as a pixel or the like. It is to provide an organic EL device that is structurally capable of manufacturing a long-life device.

[Means for Solving the Problems] The present invention has been made to achieve the above object, and an organic EL device of the present invention has a light emitting layer made of a fluorescent organic solid between two electrodes facing each other. In an organic electroluminescent device (organic EL device) having a laminated structure in which at least is interposed, the outer surface of the laminated structure has a chlorotrifluoroethylene homopolymer, a dichlorodifluoroethylene homopolymer, and chlorotrifluoro At least one polymer selected from the group consisting of copolymers of ethylene and dichlorodifluoroethylene, which is formed by a vapor deposition method using a polymer having a molecular weight of 400 to 600,000 as a vapor deposition source 1 It is characterized in that it is covered with a fluorine-containing polymer thin film having a layered or multi-layered structure.

 Hereinafter, the present invention will be described in detail.

The feature of the organic EL device of the present invention is that, as described above, the outer surface of the laminated structure constituting the organic EL device is covered with a specific fluorine-based polymer thin film. It prevents the ingress of water and oxygen.

This fluoropolymer thin film is, as described above, chlorotrifluoroethylene. Homopolymer of dichlorodifluoroethylene The homopolymer and the copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene described above are used as a vapor deposition source to form a film.

Here, when using a copolymer as a vapor deposition source, the copolymerization ratio in this copolymer does not matter. Further, the formation of the vapor deposition source is not particularly limited, and may be appropriately selected depending on the type of vapor deposition method applied at the time of film formation, such as powder, granular, bulk, disc, and pellet, Its molecular weight is limited to 400 or more and 600,000 or less. When the molecular weight is less than 400, the moisture resistance of the obtained thin film is not sufficient. A particularly preferred molecular weight is 1000-500000.

A particularly preferable polymer as the vapor deposition source is chlorotrifluoroethylene homopolymer, and specific examples thereof include Daiflon CTFE (trade name) manufactured by Daikin Industries, Ltd. and Ke manufactured by 3M Company.
l-F CTFE (trade name) and the like can be mentioned.

As a vapor deposition method for forming a thin film using such a vapor deposition source, a vacuum vapor deposition method (including a vapor deposition polymerization method), a sputtering method, a chemical vapor deposition method (CVD method), or the like can be applied. However, it is particularly preferable to apply the vacuum deposition method or the sputtering method. The vacuum deposition method and sputtering method
For example, it can be subdivided as follows, but any method can be applied.

Vacuum evaporation method Resistance heating method, Electron beam heating method, High frequency induction heating method,
Reactive vapor deposition, molecular beam epitaxy, hot wall vapor deposition, ion plating, cluster ion beam method, etc.

Sputtering method 2-pole sputtering method, 2-pole magnetron sputtering method, 3-pole and 4-pole plasma sputtering method, reactive sputtering method, etc.

The film forming conditions vary depending on the type of vapor deposition method to be applied. For example, in the case of a vacuum vapor deposition method (a resistance heating method, an electron beam heating method, a high frequency induction heating method), the degree of vacuum is 1 × the vacuum degree before vapor deposition.
10 ⁻² Pa or less, preferably 6 × 10 ⁻³ Pa or less, the heating temperature of the vapor deposition source is 700 ° C. or less, preferably 600 ° C. or less, and the vapor deposition rate is 50 nm / sec or less, preferably 3 nm / sec or less, It is desirable to form the film at a substrate temperature of 200 ° C. or lower, preferably 100 ° C. or lower.

The film thickness is 1 nm or more, preferably 10 nm or more and 100 μm or less. If the film thickness is less than 1 nm, it will not be a uniform thin film. Further, a film having a film thickness of more than 100 μm is not practical because it takes time to manufacture.

When the fluorine-based polymer thin film is formed in this way,
The characteristics of the fluorescent organic solid, which is the material of the light emitting layer, are hardly deteriorated due to the formation of this thin film. And, the fluorine-based polymer thin film thus obtained is a thin film without pinholes made of the same polymer as the polymer used as the vapor deposition source, so that the electrical resistivity, the dielectric breakdown strength, accompanying the thinning, The decrease in moisture proof property is small, and it is excellent in electrical resistivity, dielectric breakdown strength, moisture proof property, etc., like the polymer used as the vapor deposition source. Further, since the fluorine-based polymer thin film is transparent, it does not adversely affect the color light emitted from the light emitting layer, and the surface covered with the thin film can be used as the light emitting surface.

The fluorine-based polymer thin film can sufficiently fulfill its role even with a single-layer structure, but may have a multilayer structure of two or more layers as necessary. In the case of a multilayer structure, the components of each layer may be the same or different.

The organic EL device of the present invention is characterized in that the outer surface of the laminated structure is covered with the above-mentioned fluoropolymer thin film, and the structure, shape, size, etc. of the other parts are
There is no particular limitation as long as it functions as an organic EL device such as an element or an organic EL lamp.

For example, the structure of the laminated structure covered with the above-mentioned fluorine-based polymer thin film is similar to that of a conventional organic EL device,
The configuration can be any one of the following.

Electrode (cathode) / luminescent layer / hole injection layer / electrode (anode) Electrode (anode) / luminescent layer / electron injection layer / electrode (cathode) Electrode (anode) / hole injection layer / luminescent layer / electron injection layer / Electrode (cathode) Electrode (anode or cathode) / light-emitting layer / electrode (cathode or anode) And such a laminated structure is usually formed on a substrate, and the size and shape of the substrate and the laminated structure. The material and the like are also appropriately selected according to the intended use of the organic EL device such as a surface light source, a pixel of a graphic display, a pixel of a television image display device, and the like.

Among the organic EL devices of the present invention, the organic EL device in which the laminated structure is formed on the substrate can be manufactured, for example, according to the following procedure.

1. Formation of First Electrode on Substrate The first electrode can be formed by a method such as a vacuum vapor deposition method, a sputtering method, a CVD method, a plating method, or a printing method depending on the electrode material.

As the electrode material at this time, a conductive metal such as gold, silver, copper, aluminum, indium, magnesium, sodium, potassium or the like, or a mixture such as a mixture of magnesium and indium made of these conductive metals, Sodium-potassium, magnesium-copper, tin-
Alloys of lead, silver-tin-lead, nickel-chromium, nickel-chromium-iron, copper-manganese-nickel, nickel-manganese-iron, copper-nickel, etc., stannic oxide, indium oxide, zinc oxide, ITO Oxides such as (indium tin oxide), compounds such as copper iodide (CuI), laminates of aluminum (Al) and aluminum oxide (Al ₂ O ₃ ), synthetic resin and silver, silicone rubber and silver, silver A material that has been conventionally used as a conductive material, such as a composite material such as borosilicate glass, can be used.

When the first electrode side (substrate side) is used as the light emitting surface, transparent electrode materials such as stannic oxide, indium oxide, zinc oxide, ITO and CuI are used in order to increase the transmittance of light emitted from the light emitting layer. Is preferably used. Also, its thickness is 10 nm
The thickness is preferably ˜1 μm, and particularly preferably 200 nm or less. Along with this, the film formation of this electrode is preferably performed by a vacuum deposition method, a sputtering method or a CVD method.

The first electrode may be an anode or a cathode, and when it is used as an anode, it is preferable to use a conductive material having a work function larger than that of a material of a second electrode (counter electrode) described later. It is preferable to use a conductive material having a low work function. Furthermore, the work function of the anode material is 4 eV.
As described above, the work function of the cathode material is preferably less than 4 eV.

As the material of the substrate on which the first electrode is formed, glass, plastic, quartz, ceramics and the like, which are the same as conventional ones, can be used. A transparent material is used when the substrate side is the light emitting surface. It is preferable that cleaning is performed by an ultrasonic cleaning method or the like before the formation of the first electrode.

When using the organic EL device as a surface light source, a substrate made of a conductive member may be used as the substrate, and in this case, the substrate can be the first electrode.

2. Formation of Light-Emitting Layer on First Electrode The light-emitting layer can be formed by a vacuum vapor deposition method, a sputtering method, a spin coating method, a casting method, etc., but with a homogeneous and smooth film (layer), Moreover, in order to obtain a film (layer) without pinholes, it is preferable to carry out by vacuum deposition. This light emitting layer may be formed directly on the first electrode, or may be formed on the first electrode via a hole injection layer or an electron injection layer.

Examples of the material for the light emitting layer include phthaloperinone derivatives, thiadiazole derivatives, stilbene derivatives, and JP-A-2-1916.
Coumarin derivatives disclosed in JP-A-94-
JP 160894, JP-A 2-209988, and JP
The organic EL device of interest is selected from among the fluorescent organic solids conventionally used as the light emitting layer material of the organic EL device, such as the distyrylbenzene derivative and the chelated oxinoid compound disclosed in JP-A-63-295695. Is appropriately selected according to the type of emission color required, the electrical and optical characteristics, the layer structure of the laminated structure, and the like. The thickness of the light emitting layer is preferably 5 nm to 5 μm.

The hole injection layer, which is formed between the light emitting layer and the first electrode as needed, injects a large number of holes into the light emitting layer even under a low applied voltage to improve the light emitting performance of the organic EL device. This is a layer provided for the purpose. Therefore, as the material of the hole injection layer, a substance having a hole transfer coefficient of at least 10 ⁻⁶ cm ² / V · sec under 10 ⁴ to 10 ⁶ V / cm is preferable as in the conventional case. Specifically, a triphenylamine derivative,
Examples thereof include polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, arylamine derivatives, hydrazone derivatives, stilbene derivatives, and phenylenediamine derivatives.

In addition, the electron injection layer, which is formed between the light emitting layer and the first electrode as needed, injects many electrons into the light emitting layer even under a low applied voltage, thereby improving the light emitting performance of the organic EL device. This is a layer provided for the purpose. Materials for this electron injection layer include nitro-substituted fluorenone derivatives, anthraquinone dimethane derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, fluorenylidene methane derivatives, anthrone derivatives, dioxazole derivatives, etc. The substances used as the material of the injection layer can be used.

The hole injection layer and the electron injection layer have charge injecting properties,
It is a layer having either transportability or barrier properties, and in addition to the organic materials exemplified above, it is also possible to use an inorganic material such as a crystalline or non-crystalline material such as Si-based, SiC-based, CdS-based, etc. it can.

The hole injecting layer and the electron injecting layer using an organic material can be formed in the same manner as the light emitting layer, and the hole injecting layer and the electron injecting layer using an inorganic material are formed by a vacuum deposition method or a sputtering method. However, for both organic and inorganic materials, the vacuum vapor deposition method is preferable for the same reason as for the light emitting layer.

3. Formation of the second electrode (counter electrode) on the light emitting layer The second electrode can be formed in the same manner as the formation of the first electrode, but prevents entry of moisture and oxygen into the light emitting layer. For this reason, it is preferable to perform the vacuum evaporation method, the sputtering method, or the CVD method. This second electrode may be formed directly on the light emitting layer, or may be formed on the light emitting layer via a hole injection layer or an electron injection layer. However, when the light-emitting layer is formed with a hole injection layer interposed therebetween, it is assumed that the hole injection layer is not interposed between the first electrode and the light-emitting layer, and the electron injection is performed on the light-emitting layer. In the case of formation through a layer, it is assumed that no electron injection layer is interposed between the first electrode and the light emitting layer.

When the second electrode is formed directly on the light emitting layer, it is preferable to form the second electrode by a vacuum evaporation method.

As the material of the second electrode, the same material as that of the first electrode can be used, but when the first electrode is the anode, it is the cathode, and when the first electrode is the cathode, it is the anode. Therefore, the material is appropriately selected.

The material of the hole injection layer or the electron injection layer formed as needed between the second electrode and the light emitting layer is as described above, but the forming method is the same as when the light emitting layer is provided. Preferably, a vacuum deposition method is used.

By forming the second electrode (counter electrode), a laminated structure is formed on the substrate.

4. Formation of Fluorine-Based Polymer Thin Film Covering Outer Surface of Laminated Structure This is formation of a characteristic part in the organic EL device of the present invention, and its material and forming method are as described above.

By forming this fluorine-based polymer thin film, the production of the organic EL device of the present invention is basically completed, but the organic EL device of the present invention further sufficiently prevents the ingress of water and oxygen into the light emitting layer. In order to improve the mechanical properties of the device and to protect the device, a glass plate is placed on the outside of the fluorine-based polymer thin film via silicone oil, or a fluorine-based polymer thin film is used. A sealing film made of resin such as epoxy resin or a protective film made of glass may be provided on the outer periphery.

[Operation] The organic material of the present invention that can be produced as described above.
In the EL device, the fluoropolymer thin film having the above-mentioned characteristics can be formed without degrading the characteristics of the fluorescent organic solid that is the material of the light emitting layer. Also,
Even when this fluorine-based polymer thin film is formed by a forming method or film forming apparatus different from the forming method of the generation layer, it is possible to manufacture the light emitting layer with a relatively short exposure time in the atmosphere. Therefore, it is possible to sufficiently prevent moisture and oxygen from entering the light emitting layer in the manufacturing process.

And, since the fluorine-based polymer thin film coating the laminated structure in the organic EL element of the present invention is excellent in electrical resistivity, dielectric breakdown strength, moisture resistance, etc., even after manufacturing, when driving the organic EL device. Also, in this case, it is possible to sufficiently prevent moisture and oxygen from entering the light emitting layer.

Furthermore, by applying a vacuum deposition method as a method for forming a laminated structure and a method for forming a thin film of a fluorine-based polymer on a substrate, the formation of the laminated structure and the film formation of a thin film of a fluorine-based polymer can be performed by one vapor deposition. It becomes possible to continuously perform in the apparatus, and in this case, the interface of each layer does not come into contact with moisture or oxygen, so that an organic EL device having a longer life can be obtained.

In the organic EL device of the present invention in which the outer surface of the laminated structure is covered with the above-mentioned fluorine-based polymer thin film provided without deteriorating the properties of the light emitting layer, the characteristics of the light emitting layer are produced in the process of manufacturing the device. It is possible to sufficiently prevent deterioration of the light emitting layer, and it is possible to sufficiently prevent deterioration of the characteristics of the light emitting layer even after manufacturing.

That is, the organic EL device of the present invention is an organic EL device that can also be used as a pixel or the like, and is an organic EL device that is structurally capable of obtaining a device having a long life.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

Example 1 IT having a thickness of 100 nm was formed on a glass plate having a size of 25 × 75 × 1.1 mm.
An O-electrode-deposited film (manufactured by HOYA Co., Ltd.) was used as a transparent support substrate. First, this transparent support substrate was ultrasonically cleaned with isopropyl alcohol for 30 minutes, then with pure water for 30 minutes, and then with isopropyl Sonicated with alcohol for 30 minutes.

Then, the transparent supporting substrate after cleaning was fixed to a substrate holder of a commercially available vacuum vapor deposition device (manufactured by Nippon Vacuum Technology Co., Ltd.), and a molybdenum resistance heating boat was filled with N, as a material for the hole injection layer.
Add 200 mg of N'-diphenyl-N, N'-bis- (3-methylphenyl)-(1,1'-biphenyl) -4,4'-diamine (hereinafter referred to as TPDA) and use other molybdenum resistance heating 200 mg of tris (8-quinolinol) aluminum (hereinafter referred to as Alq.) Was put into the boat as a material for the light emitting layer, and the pressure in the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa.

After this, put a molybdenum resistance heating boat containing TPDA.
ITO that forms a transparent support substrate by heating to 215-220 ℃
TPDA is deposited on the film at a deposition rate of 0.1 to 0.3 nm to obtain a film thickness.
A 60 nm hole injection layer was formed. At this time, the substrate temperature was room temperature.

Next, while keeping the transparent support substrate on which the hole injection layer was formed on the substrate holder, a molybdenum resistance heating boat containing Alq. Was heated to 265 to 273 ° C. Alq. Is deposited at a deposition rate of 0.2 nm to obtain a film thickness of 60 nm.
Was formed into a light emitting layer. The substrate temperature at this time was also room temperature.

Next, 1 g of magnesium was placed as an electrode material in a resistance heating boat made of molybdenum, and 500 mg of indium was placed as an electrode material in another resistance heating boat made of molybdenum, and the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁴ Pa.

Next, the resistance heating boat made of molybdenum containing magnesium is heated to about 500 ° C, and the resistance heating boat made of molybdenum containing indium is heated to about 800 ° C, respectively, and magnesium is deposited on the light emitting layer at a deposition rate of 1.7 to 2.8 nm. And at the same time, indium was deposited at a vapor deposition rate of 0.03 to 0.08 nm to form a 150 nm thick electrode (counter electrode) made of a mixed metal of magnesium and indium. The substrate temperature at this time was also room temperature.

After that, the outer surface of the laminated structure composed of the ITO electrode, the hole injection layer, the light emitting layer, and the counter electrode formed on the glass plate was formed using the same device as the vacuum vapor deposition device used for forming the laminated structure. And coated with a fluoropolymer thin film in the following manner.

First, as shown in FIG. 1, a tungsten basket resistance heater 3 disposed in a vacuum chamber 2 constituting a vacuum vapor deposition apparatus 1 was placed on a commercially available chlorotrifluoroethylene homopolymer ( Product name: Kel-F,
An alumina crucible 4 containing 1.5 g of 3M, molecular weight 100000, hereinafter referred to as PCTFE) was placed, and a 12 μmφ stainless steel mesh 5 was placed on the alumina crucible 4.

In addition, the transparent support substrate 6 after forming the laminated structure,
It was arranged above the tungsten basket resistance heating element 3 via a shutter 7.

Next, after decompressing the inside of the vacuum chamber 2 to 1 × 10 ⁻⁴ Pa, the tungsten basket resistance heating element 3 is energized to heat the vapor deposition source to 478 ° C.
A 1.2 μm thick fluoropolymer thin film (PCTFE thin film) was deposited at a deposition rate of 0.5 nm / sec to obtain an organic EL device of the present invention. The substrate temperature at this time was also room temperature.

The film thickness and vapor deposition rate of each layer except the ITO electrode are
Control was performed while monitoring the film thickness of the vapor deposition film by a crystal vibration type film thickness meter (manufactured by Nippon Vacuum Technology Co., Ltd.) 8 arranged in the vacuum chamber 2. Further, the film thickness of each layer obtained was measured with a stylus type film thickness meter, and it was confirmed that the film thickness was in agreement with the reading of the crystal vibration type film thickness meter 8. The crystal vibrating film thickness meter 8 is provided with a support 9 containing a cooling water pipe for cooling the crystal vibrating film thickness meter 8. The support 9 is a vacuum chamber 2 It is supported by a support wall 10 arranged on the outer side of.

Example 2 An organic EL device of the present invention was obtained in the same manner as in Example 1 except that the thickness of the PCTFE thin film was 400 nm (0.4 μm).

Comparative Example An organic EL device was obtained in the same manner as in Example 1 except that the PCTFE thin film was not formed.

Life test of organic EL devices Organics obtained in Example 1, Example 2, and Comparative Example
After leaving the EL device in the atmosphere for 2 days, a constant value of direct current (1.0 mA) was continuously applied to each sample, and the brightness and the applied voltage were measured in the atmosphere at regular intervals.

Of these results, the measurement result of the luminance is shown in FIG. 2a, and the measurement result of the applied voltage is shown in FIG. 2b.

In addition, as shown in FIG. 3, the measurement of the brightness is performed by using the ITO electrode 22 provided on the surface of the substrate 21 of the organic EL device 20 as an anode, and through the hole injection layer 23 and the light emitting layer 24 on the ITO electrode 22. The counter electrode 25 provided is used as a cathode, and a current is continuously supplied from the current generator 26 to the organic EL device 20, and the light L from the organic EL device 20 is photoelectrically converted by the photodiode 27, and the light is emitted from the photodiode 27. It was carried out by calculating the relative luminance from the value of the output voltage of. The applied voltage was measured with a voltmeter 28 over time, as shown in FIG. In the organic EL device 20 shown in FIG. 3, the outer surface of the laminated structure including the ITO electrode 22, the hole injection layer 23, the light emitting layer 24, and the counter electrode 25 is covered with the PCTFE thin film 29. .

As is clear from FIGS. 2a and 2b, the lifetime of the organic EL devices of the present invention obtained in Example 1 and Example 2 is the same as that of the comparative example in which a part of the light emitting layer is exposed in the atmosphere. Organic
Overwhelmingly longer than the life of EL devices. This shows that the PCTFE thin film prevents moisture and oxygen from entering the light emitting layer.

[Effects of the Invention] As described above, by carrying out the present invention,
It becomes possible to provide an organic EL device having a long life as a device.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the vacuum vapor deposition apparatus used in Example 1, and FIG. 2a is a diagram showing a constant current flowing through each of the organic EL devices obtained in Example 1, Example 2 and Comparative Example. FIG. 2b is a graph showing the result of time-dependent measurement of the luminance when continued, and FIG. 2b shows each organic material obtained in Example 1, Example 2 and Comparative Example.
FIG. 3 is a graph showing the results of measuring the applied voltage with time when a constant value of current was continuously applied to the EL device, and FIG. 3 shows the organic EL devices obtained in Example 1, Example 2 and Comparative Example. FIG. 3 is a schematic view of an apparatus used to measure luminance and applied voltage over time when a constant current is continuously supplied. 20 …… Organic EL device, 21 …… Substrate, 22 …… ITO electrode, 2
3 …… Hole injection layer, 24 …… Light emitting layer, 25 …… Counter electrode, 29
...... PCTFE thin film.

Claims (2)

(57) [Claims] 1. An organic electroluminescent device having a laminated structure in which at least a light emitting layer made of a fluorescent organic solid is interposed between two electrodes facing each other, wherein the outer surface of the laminated structure is chlorotritin. At least one polymer selected from the group consisting of fluoroethylene homopolymer, dichlorodifluoroethylene homopolymer, and copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, having a molecular weight of 400 to 6
An organic electroluminescent device characterized by being coated with a fluorine-containing polymer thin film having a single-layer or multi-layer structure, which is formed by an evaporation method using a polymer of 00000 as an evaporation source. 2. The thickness of the fluoropolymer thin film is 1 nm or more and 100.
The organic electroluminescent device according to claim 1, which has a thickness of not more than μm.