JP2000164355A - Organic el element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption even when copper phthalocyanine(CuPc) organic film is made thick, to drive it with a lower voltage for low power consumption, to improve the transmission factor of the red section of visible light through the CuPc organic film and to obtain a desired luminescence color. SOLUTION: An anode 4 made of a transparent conductive film 3 in the prescribed pattern shape is formed on a glass substrate 2. A hole injection CuPc organic film 5a is formed on the anode 4 as a plasma polymerized film having an improved transmission factor of red luminescence at the thickness of 1 μm or above by an ion plating method. The CuPc organic film 5a is exposed to the atmosphere of NO2 which is an electron-acceptive gas after it is formed, and it contains NO2 in it. The conductivity of the CuPc organic film 5a is increased, and hole injection efficiency is stabilized and improved. An α-NPD organic film 5b and an Alq3 organic film 5c are formed in this order on the CuPc organic film 5a to obtain an organic layer 5, and a cathode 6 is formed on the Alq3 organic film 5c. A container section is fixed to the peripheral portion of the glass substrate 2 to protect the anode 4, organic layer 5 and cathode 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film of an organic EL compound utilizing electroluminescence (hereinafter referred to as EL) of an organic compound material which emits light by injection and recombination of electrons and holes (holes). Organic EL
The present invention relates to an element and a method for manufacturing the same.

[0002]

2. Description of the Related Art An organic EL device has a laminated structure in which a thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and excitons are injected into the thin film by injecting electrons and holes and recombining them. (Exciton) is generated, and the display element performs display by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated.

FIGS. 9A to 9G are side sectional views showing the structure and manufacturing process of a conventional organic EL device of this type.

The organic EL element 31 is provided on an insulating and transparent glass substrate 32 as shown in FIG.
A transparent conductive film 33 made of O (Indium Tin Oxide) is formed. The transparent conductive film 33 is formed on a glass substrate 32 and patterned into a predetermined pattern as shown in FIG. 9B to form an anode 34.

[0005] On the anode 34, an organic layer 35 of a thin film of an organic compound material is laminated. As shown in FIG.
(C) a copper phthalocyanine (CuPc) organic film 35a as a hole injection layer formed on the anode 34,
As a hole transport layer formed on the CuPc organic film 35a shown in FIG. 9D, α-NPD (Bis (N- (1
-Naphtyl-N-phneyl) benzidine) Organic film 35b
And a tris (8-quinolinolato) aluminum (Alq ₃ ) organic film 35c as a light emitting layer and an electron transport layer formed on the α-NPD organic film 35b shown in FIG. Is formed.

As shown in FIG. 9F, the organic layer 35 (A
On the lq ₃ organic film 35c), a cathode 36 made of a metal thin film such as Al-Li is formed.

[0007] As shown in FIG.
A container portion 37 as a sealing member is fixed to the outer peripheral portion of the outer peripheral portion of the container with an adhesive in a dry atmosphere with an inert gas (for example, dry nitrogen) or dry air from which water is removed as much as possible.

The organic EL element 31 constructed as described above
Then, a voltage is applied between the anode 34 and the cathode 36 to flow a constant current. As a result, holes are injected from the anode 34 and electrons are injected from the cathode 36 into the organic layer 35.
Then, the injected electrons and holes recombine to generate excitons, and a desired display is performed by emission of light when the excitons are deactivated. Light emission at this time is observed from the glass substrate 32 side via the anode 34 of the transparent conductive film 33.

[0009]

Incidentally, the organic EL element 31 configured as described above has a CuPc organic film 35a as a hole injection layer of the organic layer 35. The CuPc organic film 35a has characteristics in which voltage-current characteristics and voltage-luminance characteristics differ depending on the film thickness.
That is, when light is emitted with a constant current or constant luminance, C
The driving voltage can be reduced as the thickness of the uPc organic film is reduced, and the driving voltage is increased as the thickness of the CuPc organic film is increased.

FIGS. 6 and 7 adopt the structure of the organic EL device of FIG. 9 and have a CuPc organic film having a film thickness of 20 nm and 10 nm.
The respective characteristics when a film is formed at 00 nm are shown. As is apparent from this figure, it can be seen that the drive voltage can be lower when the CuPc organic film is formed with a thickness of 20 nm than when the organic film is formed with a thickness of 1000 nm.

Specifically, in view of the current, in order to supply a current of 15 mA / cm ² required for driving the organic EL element, as shown in FIG.
m requires a drive voltage of about 5.8V,
At 1000 nm, 15 mA / cm ² could not be obtained, and the device could not be practically used.

In addition, in terms of luminance, in order to obtain a luminance of 400 cd / m ² , which is generally required as a display element, as shown in FIG. 7, as shown in FIG. Drive voltage is required, while 100
At 0 nm, it was impossible to obtain 400 cd / m ² .

Therefore, in order to obtain higher luminance with the organic EL device 31 having the configuration shown in FIG. 9, the thickness of the CuPc organic film had to be reduced to 20 nm.

Japanese Patent Application Laid-Open No. Sho 59-194393 (Japanese Patent Publication No. 6-32307) discloses that the hole injection zone and the organic emission zone are formed as an organic layer having a thickness of 100 mm.
There is disclosed an organic electroluminescent device having a structure of being stacked between an anode and a cathode so as not to exceed 0 nm.

However, the above-described apparatus also has the following problems, including the above-mentioned problem caused by the CuPc organic film. That is, the anode serving as the base of the organic layer is
When formed by TO, the surface becomes an uneven surface of several tens nm including spike-shaped protrusions. In addition, the surface of the glass substrate serving as an underlayer of ITO has a moderate but uneven surface.

An ITO is formed on a glass substrate having an uneven surface to form an anode.
When a hole injection zone, an organic emission zone, and a cathode, which form an organic layer, are sequentially stacked on the TO to form a film, ITO is formed.
The spike-like projections may cause an electrical short between the anode and the cathode, resulting in poor insulation.

In the case where fine dust or the like at the place where the film is to be deposited or the surroundings is adhered to the surface of the already formed anode, an organic layer and a cathode are sequentially formed on the anode as it is to completely remove the gap due to the dust and the like. Can not be buried in. For this reason,
It is easy to cause an electrical short between the anode and the cathode through the gap. Moreover, when the dust attached to the anode has conductivity, there is a high possibility that the anode and the cathode are electrically short-circuited through the dust.

Therefore, in order to solve the above-mentioned problem, it is necessary to increase the thickness of the organic layer to some extent to increase the tolerance to dust and the like, and to smooth the surface of the electrode serving as the base of the organic layer. Was.

However, as described above, when the CuPc organic film formed as the organic layer on the transparent conductive film is particularly thick, the voltage-current characteristics and the voltage-luminance characteristics shift to higher voltages. As a result, in order to emit light with the same luminance as that before the CuPc organic film is made thicker, a higher driving voltage is required, which causes a problem that power consumption increases.

Further, the CuPc organic film formed by molecular beam evaporation has an absorption band in the green to red region, and when the light emission of the light emitting layer contains a large amount of red component, most of the light emission is C
Since it is absorbed by the uPc organic film, sufficient red light emission luminance cannot be obtained.

Therefore, in the configuration in which the organic layer includes the CuPc organic film, as the thickness of the CuPc organic film increases, light of red and green components in the CuPc organic film becomes more difficult to pass. As a result, the luminance of the component having a longer wavelength than that of green is reduced, and the color becomes blue even when white light is to be obtained, and a desired light emission color cannot be obtained.

By the way, CuP constituting a part of the organic layer
The c film shows p-type conduction.
_When a strong electron-accepting (oxidizing) gas such as ₂ adsorbs,
It is known that gas molecules have the property of receiving π electrons of a cyclic atomic group of a CuPc film, generating holes in the film, and increasing the conductivity of the film.

In view of the above, the present invention makes it possible to reduce the power consumption and drive at a lower voltage even if the thickness of the CuPc organic film is increased by utilizing the above-mentioned properties of the CuPc film.
It is an object of the present invention to provide an organic EL device capable of obtaining a desired emission color by improving the transmittance of a visible red light portion of a CuPc organic film, and a method of manufacturing the same.

[0024]

In order to achieve the above-mentioned object, according to the present invention, an organic layer including a hole-injecting CuPc organic film between a pair of electrodes, at least one of which is a transparent conductive film, is provided. The stacked organic EL device is characterized in that the CuPc organic film is a film containing an electron-accepting gas formed by an ion plating method with a thickness of 1000 nm or more.

According to a second aspect of the present invention, in the organic EL device according to the first aspect, the electron accepting gas comprises NO ₂ .

According to a third aspect of the present invention, there is provided a method of forming a hole-injecting Cu between a pair of electrodes, at least one of which is formed of a transparent conductive film.
In the method for manufacturing an organic EL device in which an organic layer including a Pc organic film is laminated, the CuPc organic film is formed to a thickness of 1000 nm or more by an ion plating method.
After the uPc organic film is formed, a step of rinsing the surface of the CuPc organic film with an electron-accepting gas is included.

According to a fourth aspect of the present invention, there is provided a method for forming a hole-injecting Cu between a pair of electrodes, at least one of which is formed of a transparent conductive film.
A method of manufacturing an organic EL device in which an organic layer including a Pc organic film is laminated, a step of dividing the CuPc organic film into a plurality of layers and forming a film with a thickness of 1000 nm or more by an ion plating method; Rinsing the surface with an electron-accepting gas every time each layer is formed.

[0028]

FIG. 1 is a partially enlarged side sectional view showing an organic EL device according to a first embodiment of the present invention, and FIG.
FIGS. 2A to 2I are side sectional views showing a manufacturing process of the organic EL device of FIG.

As shown in FIG. 1, the organic EL element 1A (1) according to the first embodiment is based on a rectangular glass substrate 2 having insulation and transparency. Glass substrate 2
On top of this, a transparent conductive film 3 such as ITO is formed.
The transparent conductive film 3 is made of P, for example, by a vacuum deposition method or a sputtering method.
100n by VD (Physical Vapor Deposition) method
m. The transparent conductive film 3 is further patterned into a predetermined pattern by etching with a photoresist pattern to form an anode 4. Part of the anode 4 is drawn out to the end of the glass substrate 2 and connected to a drive circuit (driver IC) (not shown).

On the anode 4, an organic layer 5 including a light emitting layer made of a thin film of an organic compound material is laminated. Organic layer 5
Is formed by a PVD method such as a molecular beam evaporation method and a resistance heating method.

The organic layer 5 in FIG.
A CuPc organic film 5a as a hole-injecting organic film formed to a thickness of 000 nm or more, and an α-NPD as a hole-transporting organic film formed to a thickness of several tens nm on the CuPc organic film 5a. Organic film 5b and α-NPD organic film 5
It has a three-layer structure including an Alq ₃ organic film 5c as a light emitting layer and an electron transporting organic film formed with a film thickness of several tens of nanometers on the substrate b.

On the organic layer 5, a cathode 6 made of a metal thin film is provided.
Are formed. The cathode 6 is made of, for example, Al, Li, M
metal material such as g, Ag, In, etc. having a small work function or A
It is made of an alloy having a small work function such as l-Li and Mg-Ag. The cathode 6 is made of P, such as a molecular beam deposition method or a resistance heating method.
The film is formed to a thickness of, for example, several tens nm to several hundreds nm (preferably, 50 nm to 200 nm) by the VD method. Part of the cathode 6 is drawn out to the end of the glass substrate 2 and connected to a drive circuit (not shown).

In a dry atmosphere using an inert gas (eg, dry nitrogen) or dry air from which moisture has been removed as much as possible, a lid-like container 7 as a sealing member is provided with an adhesive (eg, ultraviolet curing) on the outer peripheral portion of the glass substrate 2. Adhesive). Thereby, both the electrodes 4 and 6 and the organic layer 5 are protected, and a high-definition organic EL device is realized.

The organic EL device 1A configured as described above
Then, a drive voltage is applied between the anode 4 and the cathode 6 from a drive circuit (not shown) to flow a constant current. Thereby, the organic layer 5
In contrast, holes are injected from the anode 4 and electrons are injected from the cathode 6. Then, the injected holes and electrons are recombined in the organic layer 5 to generate excitons, and a desired display is performed by emission of light when the excitons are deactivated. At this time, light is emitted from the glass substrate 2 through the anode 4 made of a transparent conductive film.
Observed from outside.

Next, a method of manufacturing the organic EL device 1A having the above configuration will be described with reference to FIGS. First, the glass substrate 2 is set in a chamber (not shown) in which the internal pressure is set to 10 ⁻⁵ Pa or less, and the transparent conductive film 3 is formed on the surface of the glass substrate 2 to a thickness of about 150 nm (FIG. 2). (A)). Subsequently, the transparent conductive film 3 is etched by a photoresist pattern to form an anode 4 having a predetermined pattern shape (FIG. 2B). This transparent conductive film 3
Can be formed by a normal sputtering method. However, in the case of the film formation by the sputtering method, the transparent conductive film 3 is polycrystallized, and flake-like irregularities caused by crystal grain boundaries are formed on the surface. Preferably. For example, IDIXO
(Product name: Idemitsu Indium X-Metal
Oxide, manufactured by Idemitsu Kosan Co., Ltd.) can form a dense and excellent surface smoothness film by forming the transparent conductive film 3 with an amorphous transparent conductive film.

The transparent conductive film made of amorphous (IDIX)
At the time of forming the transparent conductive film 3 of O), mask evaporation may be performed in order to perform desired patterning. In some cases, after the transparent conductive film 3 is formed, the transparent conductive film 3 may be patterned using a normal photolithography method.

After the anode 4 is formed of the transparent conductive film 3, a CuPc organic film 5a is formed on the anode 4 to a thickness of 1000 nm or more (FIG. 2C). For example, 1000n
When the CuPc organic film 5a having a thickness of m is formed, the CuPc organic film 5a is formed into 10 times with a thickness of 100 nm each time by a PVD method such as a molecular beam evaporation method and a resistance heating method.

The CuPc organic film 5a is formed as shown in FIG.
Are used. The ion plating apparatus 11 has a vacuum chamber 12 for setting the inside to a desired vacuum atmosphere by using an exhaust means (not shown). A substrate holder 13 is provided above the vacuum chamber 12. The substrate holder 13 detachably holds the glass substrate 2 for depositing the CuPc organic film 5a. A substrate bias power supply 14 is connected to the substrate holder 13, and is configured so that plasma described later can be accelerated and drawn to the glass substrate 2. A heating means 15 is provided below the vacuum chamber 12. If the evaporation source 17 is placed in a boat 16 made of W, Mo, or the like, and is placed on the heating means 15 and heated, the evaporation source 17 evaporates due to heat. A coil electrode 18 is arranged on the upper side of the heating means 15 in the vacuum chamber 12. Coil electrode 18
Is connected to an RF power source 20 via a matching circuit 19, and can apply energy to nearby molecules to generate plasma. A gas introduction pipe 22 is connected to the vacuum chamber 12 via a gas introduction valve 21 so that a desired amount of an atmospheric gas can be introduced into the inside of the vacuum chamber 12.

The CuPc organic film 5 is formed on the transparent conductive film 3 of the glass substrate 2 by using the ion plating apparatus 11.
a is formed. First, the heating means 15 in the vacuum chamber 12
A boat 16 of W or Mo is installed. CuPc is put into the boat 16. The inside of the vacuum chamber 12 is evacuated to a degree of vacuum of 10 ⁻⁵ Torr or less. Next, the heating means 15 is energized to heat the boat 16 to a temperature of about 400 to 500 ° C. to evaporate CuPc. At this time, the gas introduction valve 21 is operated to introduce a gas such as Ar into the vacuum chamber 12 to increase the degree of vacuum to 10 ^-1 to 10 ^-4 Torr or more, and apply high frequency power to the coil electrode 18 to generate plasma. generate. When an accelerating voltage of 500 V or less is applied to the substrate holder 13, the plasmanized CuPc moves toward the glass substrate 2 attached to the substrate holder 13 and deposits on the transparent conductive film 3 of the glass substrate 2 to form a plasma polymerized film. CuPc organic film 5 as
Generate a.

When the CuPc organic film 5a is formed as described above, as a first gas rinsing process of the CuPc organic film 5a, N.sub.2 is placed in a chamber in which the glass substrate 2 is set.
Aging is performed by introducing _two gases (FIG. 2D). Specifically, in the first gas rinsing process, N ₂ gas is supplied at a flow rate of, for example, 100 ml / mn and the pressure in the chamber is 10 to 1
It is introduced until the pressure becomes 00 Pa and left for 5 minutes. This first
Not to introduce an electron-accepting strong NO ₂ gas Gasurinsu process, when suddenly introducing the NO ₂ gas into the chamber, there is a possibility of causing an explosion or the like by reacting with the residual gas in the chamber.

Following the first gas rinsing process, C
As a _second gas rinsing process of the uPc film 5a, NO ₂ gas is introduced into the chamber to replace N ₂ gas with NO ₂ gas (FIG. 2E). Specifically, in the _second gas rinsing process, NO ₂ gas is introduced at a flow rate of, for example, 100 ml / mn until the pressure in the chamber becomes 10 to 100 Pa, and left for 10 minutes. Thereby, N in the chamber is
Immediately after the film formation, the O ₂ gas is brought into contact with the CuPc organic film 5a without being exposed to the atmosphere. Then, the NO ₂ gas is sufficiently adsorbed on the surface of the CuPc organic film 5a, and the NO ₂ gas penetrates into the film.

When the second gas rinsing process is completed, the inside of the chamber is evacuated again to reduce the pressure in the chamber to 10 ^-5.
In the state where the pressure is set to Pa or less, α-
PVD of the NPD organic film 5b by molecular beam evaporation, resistance heating, etc.
A film is formed by the method D (FIG. 2F). Then, α-NP
An Alq ₃ organic film 5c is formed on the D organic film 5b (FIG. 2).
(G)) Further, a metal thin film (for example, an Al—Li film) serving as the cathode 6 is formed on the Alq ₃ organic film 5c by a PVD method (FIG. 2H).

Thereafter, the container portion 7 as a sealing member is fixed to the outer peripheral portion of the glass substrate 2 with an ultraviolet curing adhesive in an atmosphere of an inert gas (eg, dry nitrogen) or dry air from which water has been removed as much as possible (FIG. 2). (I)).
Thereby, the inner anode 4, the organic layer 5, and the cathode 6 are protected, and the organic EL element 1A is completed.

Next, FIG. 4 is a view showing a second embodiment of the organic EL device according to the present invention, and FIGS. 5 (a) to 5 (j) are views showing the steps of manufacturing the organic EL device of FIG. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the organic EL device 1B of the second embodiment, the CuPc organic film 5a formed on the anode 4 is formed into a plurality of layers by a PVD method such as a molecular beam evaporation method or a resistance heating method. The structure is such that the NO ₂ gas is sufficiently adsorbed on the surface of each layer every time each layer is formed. Other configurations are the same as those of the organic EL element 1A of the first embodiment.

In manufacturing the organic EL element 1B, the steps up to forming the first layer of the CuPc organic film 5a are performed in the same steps as in the case of manufacturing the organic EL element 1A of the first embodiment. (FIGS. 5A to 5C).

When the first layer of the CuPc organic film 5a is formed on the anode 4 by the above-described ion plating method, as a first gas rinsing process, N ₂ gas is introduced into a chamber in which the glass substrate 2 is set. It is introduced and aged (FIG. 5D). Specifically, in the first gas rinsing process, N ₂ gas is introduced at a flow rate of, for example, 100 ml / mn until the pressure in the chamber becomes 10 to 100 Pa, and 5
Leave for a minute.

Following the first gas rinsing process, as a _second gas rinsing process, NO ₂ gas is introduced into the chamber to replace N ₂ gas with NO ₂ gas (FIG. 5).
(E)). Specifically, in the second gas rinsing process, N
O ₂ gas is introduced at a flow rate of, for example, 100 ml / mn until the pressure in the chamber becomes 10 to 100 Pa, and left for 10 minutes. As a result, the first CuPc organic film 5a is exposed to the NO ₂ gas in the chamber immediately after film formation without being exposed to the atmosphere.
Contact the layer. Then, the NO ₂ gas is sufficiently adsorbed on the surface of the CuPc organic film 5a, and the NO ₂ gas penetrates into the film.

After the second gas rinsing process is completed, a second layer of the CuPc organic film 5a is formed on the first layer by ion plating. 2 of the CuPc organic film 5a.
Until the CuPc organic film 5a is formed with a desired film thickness (1000 nm or more) for the subsequent layers, the second gas rinsing process is performed each time each layer is formed (FIG. 5F). .

That is, the desired CuPc organic film 5a
Is a film thickness of M (nm) (where M> 0 nm), and a film thickness formed at one time is H (nm). The film is formed to satisfy. Specifically, the desired thickness of the CuPc organic film is 10
00 nm and the film thickness formed at one time is 100 nm
In this case, the CuPc organic film is formed in ten divided steps. Then, the second gas rinsing process is performed each time the film formation is completed ten times.

After the CuPc organic film 5a having a desired film thickness is formed and the second gas rinsing process is completed for each layer,
The chamber is evacuated again, and the pressure in the chamber is reduced to 1
An α-NPD organic film 5b is formed on the CuPc organic film 5a by a PVD method such as a molecular beam evaporation method or a resistance heating method under the condition of 0 ⁻⁵ Pa or less (FIG. 5G). Then, α-
An Alq ₃ organic film 5c is formed on the NPD organic film 5b (FIG. 5 (h)), and a cathode 6 is further formed on the Alq ₃ organic film 5c.
A metal thin film (for example, an Al—Li film) is formed by a PVD method (FIG. 5I).

Thereafter, the container 7 as a sealing member is fixed to the outer peripheral portion of the glass substrate 2 with an ultraviolet-curing adhesive in an atmosphere of an inert gas (eg, dry nitrogen) or dry air from which water has been removed as much as possible (FIG. 5). (J)).
Thereby, the internal anode 4, organic layer 5 and cathode 6 are protected, and the organic EL element 1B is completed.

As described above, the organic EL of each of the above embodiments is
According to the element 1 (1A, 1B), the CuPc organic film 5a constituting a part of the organic layer 5 contains NO ₂ as a gas having a strong electron accepting (oxidizing) property. The conductivity is increased, and the hole injection efficiency can be stably improved. Thereby, the threshold value of the current in the voltage-current characteristics can be shifted to the lower voltage side.
As a result, even when the organic EL element 1 is dynamically driven, a voltage for obtaining a desired luminance can be set to a low voltage, and a driving circuit (driver IC)
Cost can be reduced. And organic EL
Since the element 1 can be driven at a low voltage, the life characteristics during lighting can be improved.

Here, the thickness of the CuPc organic film is set to 1000.
FIGS. 6 and 7 show voltage-current characteristics and voltage-luminance characteristics of the organic EL element according to the present embodiment (second embodiment) and the conventional organic EL element when nm is set.

A comparison between the characteristics of the organic EL device of the present embodiment and the characteristics of the conventional organic EL device based on FIGS. 6 and 7 shows that, when a current of 15 mA / cm ² is applied to the organic EL device, FIG. As shown in (1), in the organic EL element 1B of the present embodiment in which the thickness of the CuPc organic film is 1000 nm, the driving voltage is about 8.5V.

On the other hand, when the thickness of the CuPc organic film is 10
As is clear from FIG. 6, the conventional organic EL device of 00 nm requires a higher driving voltage than the organic EL device of the above embodiment.

When a luminance of 400 cd / m ² is obtained, as shown in FIG.
In the case of the organic EL element of this embodiment having a thickness of 00 nm, the driving voltage is about 9 V.

On the other hand, if the thickness of the CuPc organic film is 10
As is clear from FIG. 7, the conventional organic EL device of 00 nm requires a higher driving voltage than the organic EL device of the above embodiment.

As described above, the thickness of the CuPc organic film is set to 10
00nm and the same current or the same brightness,
According to the organic EL device of the present embodiment, it can be seen that the voltage-current characteristics of FIG. 6 and the voltage-luminance characteristics of FIG. 7 can be shifted to a lower voltage side than the conventional organic EL device.

Therefore, when the thickness of the CuPc film is the same, according to the organic EL elements 1A and 1B of each embodiment, it is possible to drive at a lower voltage than the conventional organic EL element, and to reduce power consumption. Reduction can be achieved.

FIG. 8 is a graph showing the Cu of the organic EL device according to the present embodiment.
It is a figure which shows the relationship between the wavelength and transmittance in a Pc organic film and the CuPc organic film of the conventional organic EL element. 8, a solid line is a transmittance curve obtained by forming a CuPc organic film to a thickness of 1000 nm by the ion plating method according to the present embodiment, and a broken line is a PVD such as a conventional molecular beam evaporation method and a resistance heating method. CuPc with a thickness of 1000 nm by the method
It is a transmittance curve at the time of forming an organic film.

As is apparent from FIG. 8, in the red region, the transmittance peak of the CuPc organic film of this embodiment is 0.95, whereas the transmittance of the conventional CuPc organic film is 0.95. Indicates 0.05. For this reason, in the CuPc organic film 5a formed by the ion plating method of the present embodiment, the transmittance in the red region is significantly improved as compared with the related art. this is,
The crystal state changes due to plasma polymerization,
This is probably because the interaction between Pc molecules was reduced, and the hiding power as a pigment was reduced. Further, according to the plating method in which high-frequency power is applied, the unevenness of the surface of the deposited plasma-polymerized film becomes small and smooth, and therefore, the reactive current that does not contribute to light emission is reduced.

As described above, in this embodiment, in addition to the above-described gas rinsing treatment, the CuPc organic film 5a is a plasma-polymerized layer having a high transmittance formed by the ion plating method. The desired light emission color can be obtained by improving the light emission transmittance. Further, the surface of the formed CuPc organic film 5a is smoother than a normal vapor-deposited film, so that the reactive current that does not contribute to light emission can be reduced.

According to the organic EL device 1B of the second embodiment, since the CuPc organic film 5a has a multilayer structure in which NO ₂ gas is adsorbed for each layer, gas molecules in the upper and lower layers of the CuPc film 5a are removed. The concentration becomes uniform, and the inclination of the NO ₂ gas molecule concentration (the distribution of points of the CuPc organic film 5a in FIGS. 1 and 4) in the thickness direction of the CuPc film 5a, that is, the variation of the gas molecule concentration can be eliminated.

In the above embodiment, CuPc
When the underlayer of the organic film 5a is a transparent conductive film, if the thickness of the CuPc organic film 5a is reduced, the CuPc organic film 5a is affected by the uneven surface of the transparent conductive film 3, so that the transparent conductive film 3 needs to be smoothed. As the smoothing process, the surface may be polished and smoothed after forming the transparent conductive film 3 such as ITO, or IDIXO may be used.
It is conceivable to form the transparent conductive film 3 with an amorphous material such as the above.

[0066] In the manufacturing method of the above described embodiments has been described as performing a second Gasurinsu processing of the first Gasurinsu processing and NO ₂ gas of the N ₂ gas in separate steps, for example, N _2: The gas rinsing process may be performed using a mixed gas having a ratio of NO ₂ = 98: 2. Thereby, the first gas rinsing process of the N ₂ gas and the _second gas rinsing process of the NO ₂ gas of the CuPc film
It can be realized in two steps.

The organic layer 5 in each embodiment is not limited to the three-layer structure shown in the drawings, but may be any structure including a CuPc organic film 5a as a hole injecting organic film and a light emitting layer.

In each embodiment, the anode 4 made of the transparent conductive film 3 and the cathode 6 made of a metal thin film may be inverted. In this case, CuPc constituting the organic layer 5
Organic film 5a, α-NPD organic film 5b, Alq ₃ organic film 5
c is also reversed and stacked. At this time, the glass substrate 2 to be used does not necessarily need to have transparency, and a colored substrate having an insulating property can be used.

The pair of electrodes (anode 4 and cathode 6)
At least one of them may be formed of a conductive material having transparency. At this time, when both electrodes are made of a transparent conductive material, one electrode (anode 4) is made of a transparent conductive material (ITO) having a large work function and the other electrode (cathode 6) is used. A conductive material having a small work function and having transparency is used.

[0070]

As is apparent from the above description, according to the organic EL device of the present invention, CuP constituting a part of the organic layer is used.
Since the organic film c contains an electron-accepting gas (NO ₂ ), the conductivity of the organic CuPc film is increased, and the hole injection efficiency can be stably improved.

As a result, the threshold value of the current in the voltage-current characteristics can be shifted to the lower voltage side. As a result, even when the organic EL element is dynamically driven, a voltage for obtaining a desired luminance can be set to a low voltage, and the cost of the driving circuit can be reduced. In addition, since the organic EL element can be driven at a low voltage, the life characteristics during lighting can be improved. In addition, since the CuPc organic film is a plasma-polymerized layer having a high transmittance formed by an ion plating method, it is difficult to absorb red light emission, and a desired light emission color can be obtained by improving the transmittance of red light emission. . In addition, the surface of the CuPc organic film formed by the ion plating method is smoother than a normal vapor-deposited film, so that a reactive current that does not contribute to light emission can be reduced.

In particular, a CuPc organic film is formed in a plurality of layers, and each time each layer is formed, an electron-accepting gas (NO ₂ )
By rinsing the surface with CuPc, the concentration of gas molecules in the upper and lower layers of the CuPc film becomes uniform, and CuPc
Variations in gas molecule concentration in the film thickness direction can be eliminated.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment of an organic EL device according to the present invention.

FIGS. 2A to 2I are side sectional views showing manufacturing steps of the organic EL device according to the first embodiment;

FIG. 3 is a diagram schematically showing a structure of an ion plating apparatus used for forming a CuPc organic film of the organic EL element of the present invention.

FIG. 4 is a partial sectional side view showing a second embodiment of the organic EL device according to the present invention.

FIGS. 5A to 5J are side sectional views showing manufacturing steps of an organic EL device according to a second embodiment.

FIG. 6 is a diagram showing voltage-current characteristics of the organic EL element of the present embodiment and a conventional organic EL element according to the thickness of a CuPc organic film.

FIG. 7 is a diagram showing voltage-luminance characteristics of the organic EL element of the present embodiment and a conventional organic EL element according to the thickness of the CuPc organic film.

FIG. 8 is a diagram showing the relationship between the wavelength and the transmittance of the CuPc organic film of the organic EL device of the present embodiment and the CuPc organic film of the conventional organic EL device.

FIGS. 9A to 9G are side sectional views showing a configuration and a manufacturing process of a conventional organic EL element.

[Explanation of symbols]

1 (1A, 1B) ... organic EL element, 3 ... transparent conductive film, 4
... Anode, 5 ... Organic layer, 5a ... CuPc organic film, 6 ... Cathode, 11 ... Ion plating apparatus.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoko Takahashi 629 Futaba Electronics Industry Co., Ltd. 629 Oshiba, Mobara City, Chiba Prefecture (Reference) 3K007 AB04 AB06 AB08 AB18 BA06 BB01 CA01 CB01 DA01 DB03 EB00 FA01 4K029 AA09 BA08 BA62 BB02 BC09 BD00 CA03 DD02 EA01

Claims (4)

[Claims] 1. An organic EL device in which an organic layer including a hole-injectable CuPc organic film is laminated between a pair of electrodes each having at least one electrode formed of a transparent conductive film, wherein the CuPc organic film has a thickness of 1000 nm or more. An organic EL device comprising a thick film containing an electron-accepting gas formed by an ion plating method. 2. The organic EL device according to claim 1, wherein said electron-accepting gas comprises NO ₂ . 3. A method of manufacturing an organic EL device in which an organic layer including a hole-injectable CuPc organic film is laminated between a pair of electrodes, at least one of which is formed of a transparent conductive film, wherein the CuPc organic film is formed by ion plating. An organic EL device comprising: forming a film with a thickness of 1000 nm or more by a coating method, and rinsing the surface of the CuPc organic film with an electron-accepting gas after the CuPc organic film is formed. Manufacturing method. 4. A method for manufacturing an organic EL device in which an organic layer including a hole-injectable CuPc organic film is laminated between a pair of electrodes each including at least one electrode formed of a transparent conductive film, A step of forming a layer with a thickness of 1000 nm or more by an ion plating method, and a step of rinsing the surface with an electron-accepting gas every time each layer of the CuPc organic film is formed. A method for manufacturing an organic EL device.