JP3615817B2 - Method for manufacturing organic electroluminescence element - Google Patents

Description

[0001]
[Industrial application fields]
The present inventionThe present invention relates to a method for manufacturing an organic electroluminescence element.
[0002]
[Prior art]
Conventionally, as this type of organic electroluminescence element (hereinafter referred to as organic EL element),
1. Anode (metal) / hole transport layer / light emitting layer / cathode (metal)
2. Anode / light-emitting layer / electron transport layer / cathode
3. Anode / hole transport layer / light emitting layer / electron transport layer / cathode
4. Anode / light emitting layer / cathode
Such a stacked organic EL element is known.
[0003]
As a stacked organic EL element, a film having at least one of an electroluminescent light emitting layer function, a charge transport function and a charge injection function as a light emitting layer material or a charge injection layer material is disclosed in Japanese Patent Application Laid-Open No. 3-274693. An organic thin film electroluminescence device using a polymer thin film having a thickness of 0.5 μm or less is disclosed, and Japanese Patent Application Laid-Open No. 6-243966 discloses an “organic EL device formed on a substrate. An organic EL device is disclosed in which an organic thin film is a light emitting layer composed of a polymer film or an oligomer film formed by vapor deposition polymerization of raw material monomers.
[0004]
Then, organic compound films such as a light emitting layer and an electron transport layer are thinned by a wet method such as spin coating and dipping, or a vacuum deposition method, and various studies have been made on their light emission characteristics.
[0005]
At present, an organic EL element having a luminance of several tens of thousands cd / m @ 2 at a driving voltage of 10 V or less has been developed, and has reached a practical level as a light emission characteristic.
[0006]
However, the deterioration at the time of driving the device is significant, causing problems such as corrosion of the cathode and crystallization of organic compounds.
[0007]
Therefore, as a means for solving these problems, research on materials for protecting the oxidation of the cathode is underway. For example, materials such as metal oxides such as MgO and CaO, or amorphous silica are known. ing.
[0008]
As a method of protecting the entire EL element by using a metal oxide such as MgO or CaO, as disclosed in Japanese Patent Laid-Open No. 5-89959, “light emission made of a fluorescent organic solid between two electrodes facing each other” is disclosed. After providing a protective layer made of an electrically insulating inorganic compound on the outer surface of the laminated structure of an organic EL element having a laminated structure in which at least a layer is interposed, an electrically insulating glass is formed outside the protective layer. Further, there is disclosed a method for sealing an organic EL device provided with a shield layer made of one selected from the group consisting of an electrically insulating polymer compound and an electrically insulating airtight fluid.
[0009]
Further, as a method for protecting with amorphous silica, JP-A-5-335080 discloses that an electroluminescent material layer containing at least one organic compound is provided between an anode and a cathode, at least one of which is transparent. An electroluminescent device in which an amorphous silica protective layer is formed on an organic thin film electroluminescent device is disclosed.
[0010]
[Problems to be solved by the invention]
As the cathode material of the conventional organic EL element, a metal having a small work function is used so that electrons can be injected more easily. An alkali metal such as lithium or an alkaline earth such as magnesium or calcium is used. Metal is said to be effective.
[0011]
However, since these alkali metals and alkaline earth metals are active, there is a problem that the performance as a cathode is remarkably deteriorated by reacting with moisture and oxygen in the atmosphere over time.
[0012]
In the case of the organic EL element sealing method disclosed in JP-A-5-89959, the organic layer deteriorates due to thermal damage caused by vapor deposition particles because the evaporation temperature of MgO is as high as 600 ° C. There is a problem that a dense MgO film cannot be formed unless the substrate temperature is 200 to 300 ° C.
[0013]
In addition, in the case of the electroluminescent element disclosed in Japanese Patent Laid-Open No. 5-335080, there is a problem that the apparatus cost is high because it is manufactured by the RF plasma CVD method using monochlorosilane.
[0014]
The present invention solves the above problems, has no instability of the cathode, and has a long service life.Provided is a method for manufacturing an organic electroluminescence device.For the purpose.
[0015]
[Means for Solving the Problems]
0016]
The method for producing an organic electroluminescence device of the present invention comprises evaporating a polyurea raw material monomer in a vacuum and vapor-depositing it on the cathode of an organic electroluminescence device comprising an anode, an organic compound film and a cathode on a substrate. After forming the polyurea film,In a vacuum atmosphere,The polyurea film is cross-linked by ultraviolet irradiation to form a polyurea protective film.
0017]
The organic compound film may be a film having at least a light emitting layer.
0018]
The polyurea raw material monomer may be a diamine monomer and a diisocyanate monomer.
0019]
[Action]
When the polyurea raw material monomer is evaporated in a vacuum, the raw material monomer is deposited on the cathode formed on the substrate, and the deposited raw material monomer of the protective film is polymerized to form a polyurea film.
0020]
Since the polyurea film formed on the cathode is a low molecular weight oligomer film, it is cross-linked by irradiating with ultraviolet rays to form a polymerized polyurea film having a network structure, which has water resistance, heat resistance and durability. It becomes an excellent protective film.
0021]
【Example】
First, the structure of the organic EL element will be described.
As the structure of the organic EL element, when an organic compound film such as an anode (ITO) / light emitting layer / cathode is a single layer structure having only a light emitting layer (consisting of a polymer film or an oligomer film), anode / hole transport When the organic compound film such as layer / light emitting layer / cathode or anode / light emitting layer / electron transport layer / cathode has a two-layer structure of a hole transport layer and a light emitting layer, or a light emitting layer and an electron transport layer, the anode / positive There may be a three-layer structure of a hole transport layer / light emitting layer / electron transport layer / cathode.
0022]
Here, as the hole transport layer of the organic compound film, for example, N, N′-diphenyl-N, N′-bis (3-methylphenyl) 1,1′-biphenyl 4,4′-diamine (hereinafter referred to as TPD). ) A thin film formed by vapor deposition of a low molecular weight dye having a hole transport ability represented by) and a polymer film (polyamide, polyimide, polyazomethine, etc.) having a hole transport molecular structure were formed by vapor deposition polymerization. A thin film may be used, and a hole transporting low molecular weight dye may be deposited and dispersed in a polymer thin film.
0023]
As the light emitting layer, for example, a thin film in which a light emitting dye represented by 8-oxyquinolino aluminum complex (hereinafter referred to as Alq3) is formed by vapor deposition or a polymer film having a conjugated structure such as stilbene or oxadiazole. A thin film formed by vapor deposition polymerization (polyurea, polyimide, polyoxadiazole, etc.) is used, and a light-emitting dye may be vapor-deposited and dispersed in a polymer thin film.
0024]
Further, as the electron transporting layer, for example, a vapor-deposited thin film of Alq3 or an oxadiazole derivative is used, and a thin film of an anthraquinodimethane derivative or a diphenylquinone derivative can also be used.
0025]
Next, specific examples of the present invention will be described.
0026]
FIG. 1 shows a structure of an organic EL element having a two-layer structure according to the present invention. An organic EL element 1 includes a substrate 2 made of, for example, an alkali-free glass, an anode 3 made of, for example, an ITO film, and a hole transport layer (or light emission). Layer) 4, light emitting layer (or electron transport layer) 5, for example, a cathode 6 made of an Mg—Ag alloy is composed of a polyurea protective film 7 and an extraction electrode 8 made of Ag.
FIG. 2 shows an example of an apparatus used for producing the organic EL element of the present invention, and does not include an anode forming apparatus. In the figure, 11 is an oxygen plasma treatment chamber, 12 is a deposition chamber for organic compound films such as a hole transport layer, a light emitting layer, and an electron transport layer, 13 is a cathode formation chamber, 14 is a protective film formation chamber, and 15 is an ultraviolet treatment. Indicates a room. The oxygen plasma processing chamber 11, film forming chamber 12, cathode forming chamber 13, protective film forming chamber 14, and ultraviolet processing chamber 15 are partitioned by a gate valve 16 that can be freely opened and closed, and the substrate 2 is placed in each chamber. A tray-type transport system 17 is disposed for transporting the.
0027]
The oxygen plasma processing chamber 11 was connected to an evacuation system 18 such as a vacuum pump, and a copper RF electrode 19 for plasma processing the ITO film was disposed in the oxygen plasma processing chamber 11.
0028]
A heater 21 (a, b) in which the inside of the film forming chamber 12 is connected to an evacuation system 20 such as a vacuum pump, and a dye raw material T such as TPD or Alq 3 is wound around one of the lower sides in the film forming chamber 12. Two alumina dye evaporation sources 22 (a, b) that are heated to a predetermined temperature and evaporated are arranged side by side, and the raw material monomers U, V of the vapor-deposition polymerized polymer film are arranged on the other lower side in the film forming chamber 12. The glass or metal organic matter evaporation sources 24 and 25 to be heated to a predetermined temperature by the infrared lamp 23 are disposed, and the pigment evaporation source 22 and the evaporation sources 24 and 25 are opposed to each other above the film forming chamber 12. The substrate 2 on which the organic compound film was to be formed was disposed, and the sheath heater 26 for heating the polymer film formed on the substrate 2 was disposed on the back side of the substrate 2.
0029]
Further, a shutter 27 (a, b) is disposed between the substrate 2 and the dye evaporation source 22 (a, b), and a shutter 28 is disposed between the substrate 2 and the organic substance evaporation sources 24, 25, respectively. In addition, thermocouples 29 and 30 are disposed in the organic matter evaporation sources 24 and 25, respectively.
0030]
The cathode forming chamber 13 is connected to an evacuation system 31 such as a vacuum pump, and one source W of the cathode 4 (the source W is Mg) is wound around one of the lower portions of the cathode forming chamber 13 around the heater 32. An alumina cathode material evaporation source 33 for heating and evaporating at a predetermined temperature is disposed, and the other raw material X of the cathode 4 (the raw material X is Ag) is set at a predetermined temperature in the other lower portion of the cathode forming chamber 13. A cathode material evaporation source 34 composed of a boat made of tungsten or molybdenum to be heated and evaporated was disposed.
0031]
In addition, a shutter 35 is disposed between the substrate 2 and the cathode material evaporation source 33, and a shutter 36 is disposed between the substrate 2 and the cathode material evaporation source 34.
0032]
The inside of the protective film forming chamber 14 is connected to an evacuation system 37 such as a vacuum pump, and the raw material monomers Y and Z of the polyurea film (the raw material Y is a diamine monomer and the raw material monomer Z is diisocyanate) below the protective film forming chamber 14. A glass or metal protective film evaporation source 39, 40 is provided for heating the salt monomer) to a predetermined temperature with an infrared heater 38 and evaporating it.
0033]
Further, shutters 41 are disposed between the substrate 2 and the protective film evaporation sources 39 and 40, respectively. Further, a quartz vibration type film thickness monitor 42 of a protective film is disposed in the vicinity of the substrate 2. Further, thermocouples 43 and 44 are disposed in the protective film evaporation sources 39 and 40, respectively.
0034]
The ultraviolet treatment chamber 15 is connected to an evacuation system 45 such as a vacuum pump, and the ultraviolet treatment chamber 15 is irradiated with ultraviolet rays to crosslink low molecular polyurea and polymerize it to form a polyurea protective film. A lamp 46 was provided.
0035]
In the figure, 47 is a partition plate provided between the organic material evaporation sources 24 and 25, and 48 is a partition plate provided between the protective film evaporation sources 39 and 40, respectively.
0036]
Next, a manufacturing example of the organic EL element shown in FIG. 1 will be described together with a comparative example using the apparatus shown in FIG.
0037]
Example 1
In this embodiment, the hole transport layer is a TPD film, the light emitting layer is an Alq3 film, and the film formation is performed using a dye evaporation source 22 (a, b) in which two evaporation sources in the film formation chamber 12 are arranged side by side. I decided to do it.
0038]
First, a 100mm vertical (100mm x 100mm x 1.1mm thickness glass substrate (Hiraoka Special Glass Co., Ltd., Corning 7059) 2) 1000mm (0.1μm) ITO (In2O3-10wt% SnO2) film cleaned by boiling in isopropanol Was formed by sputtering.
0039]
Next, after the substrate 2 is charged into the oxygen plasma processing chamber 11 with the gate valve 16 between the chambers closed and attached to the transfer system 17, the inside of the oxygen plasma processing chamber 11 is pressurized to 6.65 Pa by the vacuum exhaust system 18. While maintaining (0.05 Torr), the substrate 2 was subjected to oxygen plasma treatment at 50 W with an oxygen gas partial pressure of 1.33 Pa (0.01 Torr) using the RF electrode 19.
0040]
The gate valve 16 between the oxygen plasma processing chamber 11 and the film forming chamber 12 is opened, and the substrate 2 that has been subjected to the oxygen plasma processing is transferred into the film forming chamber 12 by the transfer system 17, and then formed with the oxygen plasma processing chamber 11. The gate valve 16 between the membrane chamber 12 was closed.
0041]
Then, the TPD of the dye material T in the dye evaporation source 22a is heated to 220 ° C. by the heater 21a while the pressure inside the film forming chamber 12 is maintained at 6.65 × 10 −4 Pa (5 × 10 −6 Torr) by the vacuum exhaust system 20. Then, after setting the evaporation rate to a predetermined value, the TPD was evaporated by opening / closing the shutter 27a, and a TPD having a thickness of 500 mm (0.05 μm) was deposited as the hole transport layer 4 on the ITO film 3 of the substrate 2.
0042]
Subsequently, similar to the formation of the hole transport layer 4 of TPD, the heater 21b heats Alq3 of the dye material T in the dye evaporation source 22b to 250 ° C., sets a predetermined evaporation rate, and then opens and closes the shutter 27b. Then, Alq3 was evaporated to deposit 500 nm (0.05 μm) of Alq3 on the hole transport layer 4 as the light emitting layer 5.
0043]
Next, the gate valve 16 between the film forming chamber 12 and the cathode forming chamber 13 is opened, and the substrate 2 on which the hole transport layer 4 and the light emitting layer 5 are formed is transferred into the cathode forming chamber 13 by the transfer system 17. Thereafter, the gate valve 16 between the film forming chamber 12 and the cathode forming chamber 13 was closed.
0044]
While the cathode forming chamber 13 is maintained at a pressure of 1.33 × 10 −4 Pa (1 × 10 −6 Torr) by the vacuum exhaust system 31, the heater 32 heats Mg in the evaporation source 33 to 450 to 480 ° C. Then, Ag in the evaporation source 34 is heated to 650 to 700 ° C., the respective evaporation rates are set so that the atomic ratio of Mg: Ag = 10: 1, and then the shutter 35 and the shutter 36 are operated to open and close the Mg and Ag. The cathode 6 made of Mg—Ag having a thickness of 2000 μm (0.2 μm) was deposited on the light emitting layer 5.
0045]
Next, the gate valve 16 between the cathode forming chamber 13 and the protective film forming chamber 14 is opened, and the substrate 2 on which the cathode 6 is formed is transferred into the protective film forming chamber 14 by the transfer system 17, and then the cathode forming chamber 13. And the protective valve forming chamber 14 were closed.
0046]
The raw material monomer Y (4,4′-diaminodiphenylmethane in the evaporation source 39: with the pressure 1.33 × 10 −3 Pa (1 × 10 −5 Torr) maintained in the protective film forming chamber 14 by the vacuum exhaust system 37: The temperature of the MDA) is measured by the thermocouple 43 and heated to 100 ° C. by the heater 38, and the temperature of the raw material monomer Z (4,4′-diphenylmethane diisocyanate: hereinafter referred to as MDI) in the evaporation source 40 is adjusted. Heating to 70 ° C. with the heater 38 while measuring with the thermocouple 44, setting the respective evaporation rates so that the monomer composition ratio of MDA: MDI is 1: 1, then opening and closing the shutter 41 evaporates MDA and MDI. The film thickness was then deposited on the cathode 6 at a deposition rate of 300 mm (0.03 μm) / min to a film thickness of 10,000 mm (1 μm) and then polymerized on the cathode 6 to form a polyurea film.
0047]
Next, the gate valve 16 between the protective film forming chamber 14 and the ultraviolet processing chamber 15 is opened, and the substrate 2 on which the polyurea film is formed is transported into the ultraviolet processing chamber 15 by the transport system 17, and then the protective film forming chamber. The gate valve 16 between 14 and the ultraviolet processing chamber 15 was closed.
0048]
Then, with the inside of the ultraviolet processing chamber 15 maintained at a pressure of 0.67 Pa (5 × 10 −3 Torr) by the vacuum exhaust system 45, light (ultraviolet) having a central wavelength of 254 nm and 10 W is applied to the polyurea film for 30 minutes from the ultraviolet lamp 46. Irradiation was performed to prepare an organic EL element 1 including the polyurea protective film 7 having a two-layer structure shown in FIG.
0049]
Next, the organic EL element 1 was taken out from the ultraviolet processing chamber 15.
0050]
When a DC voltage of 7 V was applied to the organic EL element 1, green light emission was confirmed.
In addition, when the organic EL element 1 was driven under conditions of constant current density 10 mA / cm 2, initial luminance 600 cd / m 2, and in the atmosphere, and the change with time was examined, the planar light emission of 330 cd / m 2 was maintained after 1000 hours. It was.
At this time, no deterioration of the device was observed except that a dark spot accompanying crystallization of TPD was observed.
0051]
Comparative Example 1
An organic EL device without a polyurea protective film was prepared according to Example 1, and this organic EL device was driven under the same conditions as in Example 1. After 48 hours, it was extinguished due to deterioration of the MgAg electrode.
0052]
Example 2
In this embodiment, the light emitting layer is a polyoxadiazole film, the electron transport layer is an Alq3 film, and the film formation is performed using the evaporation sources 24 and 25 in the film forming chamber 12 and the dye evaporation source 22b. .
0053]
First, 1000mm (0.1μm) ITO (In2O3-10wt% SnO2) film on a glass substrate (Hiraoka Special Glass Co., Ltd., Corning 7059) 100mm long x 100mm wide x 1.1mm thick cleaned by boiling in isopropanol Was formed by sputtering.
0054]
Next, after the substrate 2 is charged into the oxygen plasma processing chamber 11 with the gate valve 16 between the chambers closed and attached to the transfer system 17, the inside of the oxygen plasma processing chamber 11 is pressurized to 6.65 Pa by the vacuum exhaust system 18. While maintaining (0.05 Torr), the substrate 2 was subjected to oxygen plasma treatment at 50 W with an oxygen gas partial pressure of 1.33 Pa (0.01 Torr) using the RF electrode 19.
0055]
The gate valve 16 between the oxygen plasma processing chamber 11 and the film forming chamber 12 is opened, and the substrate 2 that has been subjected to the oxygen plasma processing is transferred into the film forming chamber 12 by the transfer system 17, and then formed with the oxygen plasma processing chamber 11. The gate valve 16 between the membrane chamber 12 was closed.
0056]
Then, with the pressure 1.33 × 10 −3 Pa (1 × 10 −5 Torr) maintained in the film forming chamber 12 by the vacuum exhaust system 20, the raw material monomer U (5-diphenylamino-1,3- While the temperature of dicarbonyl chloride benzene (hereinafter referred to as TPA-3.5DC) is measured with a thermocouple 29 and heated to 108 ° C. with the heater 23, the raw material monomer V in the evaporation source 25 (terephtalic acid dihitrazide: hereinafter referred to as TPDH) Is heated to 225 ° C. with the heater 23 while measuring with the thermocouple 30 and the respective evaporation rates are set so that the monomer composition ratio of TPA-3.5DC: TPDH becomes 1: 1, and then the shutter 28 is opened and closed. TPA-3.5DC and TPDH are evaporated by a film thickness monitor (not shown) to a film thickness of 700 mm (0.07 μm) at a deposition rate of 50 mm (0.005 μm) / min on the ITO film 3 on the substrate 2. Deposited To form a polyhydrazide film polyoxadiazole precursors by polymerizing while.
The precursor polyhydrazide film was subjected to heat treatment at 300 ° C. by a sheath heater 26 to obtain a polyoxadiazole film having a thickness of 500 mm (0.05 μm) as the light emitting layer 4.
0057]
Subsequently, the heater 21b heats Alq3 of the dye raw material T in the dye evaporation source 22b to 250 ° C., sets a predetermined evaporation rate, evaporates Alq3 by opening and closing the shutter 27b, and causes electrons on the light emitting layer 4 to be evaporated. Alq 3 having a thickness of 500 mm (0.05 μm) was deposited as the transport layer 5.
0058]
Next, the gate valve 16 between the film forming chamber 12 and the cathode forming chamber 13 is opened, and the substrate 2 on which the light emitting layer 4 and the electron transport layer 5 are formed is transferred into the cathode forming chamber 13 by the transfer system 17. The gate valve 16 between the film forming chamber 12 and the cathode forming chamber 13 was closed.
0059]
While the cathode forming chamber 13 is maintained at a pressure of 1.33 × 10 −4 Pa (1 × 10 −6 Torr) by the vacuum exhaust system 31, the heater 32 heats Mg in the evaporation source 33 to 450 to 480 ° C. Then, Ag in the evaporation source 34 is heated to 650 to 700 ° C., the respective evaporation rates are set so that the atomic ratio of Mg: Ag = 10: 1, and then the shutter 35 and the shutter 36 are operated to open and close the Mg and Ag. Then, a cathode 6 made of Mg—Ag having a thickness of 2000 μm (0.2 μm) was deposited on the electron transport layer 5.
0060]
Next, the gate valve 16 between the cathode forming chamber 13 and the protective film forming chamber 14 is opened, and the substrate 2 on which the cathode 6 is formed is transferred into the protective film forming chamber 14 by the transfer system 17, and then the cathode forming chamber 13. And the protective valve forming chamber 14 were closed.
0061]
Then, the temperature of the raw material monomer Y (MDA) in the evaporation source 39 is set to a thermoelectric state with the pressure inside the protective film forming chamber 14 maintained at 1.33 × 10 −3 Pa (1 × 10 −5 Torr) by the vacuum exhaust system 37. While being measured by the pair 43, the heater 38 is heated to 100 ° C., and the temperature of the raw material monomer Z (MDI) in the evaporation source 40 is heated to 70 ° C. by the thermocouple 44 while being measured by the thermocouple 44. After setting the respective evaporation rates so that the monomer composition ratio becomes 1: 1, MDA and MDI are evaporated by opening and closing the shutter 41, and 300 mm (0.03 μm) / min on the cathode 6 by the film thickness monitor 42 After depositing at a deposition rate to a film thickness of 10,000 μm (1 μm), polymerization was performed on the cathode 6 to form a polyurea film.
0062]
Next, the gate valve 16 between the protective film forming chamber 14 and the ultraviolet processing chamber 15 is opened, and the substrate 2 on which the polyurea film 7 is formed is transferred into the ultraviolet processing chamber 15 by the transfer system 17 and then the protective film is formed. The gate valve 16 between the chamber 14 and the ultraviolet processing chamber 15 was closed.
0063]
Then, with the inside of the ultraviolet processing chamber 15 maintained at a pressure of 0.67 Pa (5 × 10 −3 Torr) by the vacuum exhaust system 45, light (ultraviolet) having a central wavelength of 254 nm and 10 W is applied to the polyurea film for 30 minutes from the ultraviolet lamp 46. Irradiation was performed to prepare the organic EL element 1 shown in FIG. 1 having the polyurea protective film 7 having a two-layer structure shown in FIG.
0064]
Next, the organic EL element 1 was taken out from the ultraviolet processing chamber 15.
0065]
When a DC voltage of 10 V was applied to the organic EL element 1, blue-green light emission was confirmed.
0066]
In addition, when the organic EL element 1 was driven under the conditions of constant current density 10 mA / cm 2, initial luminance 300 cd / m 2, and in the atmosphere, and the change with time was examined, planar light emission of 120 cd / m 2 was maintained after 1000 hours. It was.
At this time, the dark spot accompanying deterioration of a light emitting layer, an electron carrying layer, and a MgAg electrode was not observed.
0067]
Comparative Example 2
An organic EL element without a polyurea protective film was prepared according to Example 2, and this organic EL element was driven under the same conditions as in Example 2. After 25 hours, the organic EL element was quenched due to deterioration of the MgAg electrode.
0068]
Example 3
In this example, the organic compound film has a single layer structure having only a light emitting layer. As the light emitting layer, TPD of a hole transporting dye is evaporated at the same time as the formation of a polyurea film having a stilbene structure. A film in which TPD is dispersed is formed using the evaporation sources 24 and 25 and the dye evaporation source 22b in the film forming chamber 12.
0069]
As in the first and second embodiments, the substrate 2 formed with the ITO film and subjected to the oxygen plasma treatment is transferred to the film forming chamber 12, and the MDI of the raw material monomer U in the evaporation source 24 is transferred into the film forming chamber 12. Is heated to 60 ° C., the raw material monomer V 4-amino-4 ′-(N, N-dimethylamino) stilbene in the evaporation source 25 is heated to 135 ° C., and the dye raw material T in the dye evaporation source 22 b is further heated. The TPD is heated to 180 ° C., the shutters 27b and 28 are opened, and the TPD is dispersed in polyurea having a stilbene structure with a thickness of 1000 mm (0.1 μm) as a light emitting layer on the ITO film 3 on the substrate 2. Formed.
0070]
Subsequently, in the same manner as in Examples 1 and 2, a cathode and a polyurea protective film were formed on the light emitting layer, and an organic EL device provided with the polyurea protective film was produced.
0071]
When this organic EL device was driven under conditions of a constant current density of 10 mA / cm 2, an initial luminance of 200 cd / m 2 and in the atmosphere, and the change with time was examined, the planar light emission of 120 cd / m 2 was maintained after 1000 hours.
0072]
Comparative Example 3
An organic EL device without a polyurea protective film was prepared according to Example 3 and was driven under the same conditions as in Example 3. As a result, after 12 hours, the organic EL device was quenched due to deterioration of the MgAg electrode.
0073]
Example 4
In this example, the organic compound film is an example of a three-layer structure comprising a hole transport layer / light-emitting layer / electron transport layer, a TPD film as the hole transport layer, a polyurea film having a stilbene structure as the light-emitting layer, and an electron transport layer As an Alq3 film.
0074]
As in the first and second embodiments, the substrate 2 on which the ITO film is formed and subjected to the oxygen plasma treatment is transferred to the film forming chamber 12, and in the film forming chamber 12, first, the dye material T in the evaporation source 22a The TPD was heated to 220 ° C., the shutter 27a was opened, and a 400 μm (0.04 μm) TPD film was deposited on the ITO film 3 on the substrate 2 as a hole transport layer.
0075]
Next, the MDI of the raw material monomer U in the evaporation source 24 is heated to 60 ° C., and the 4-amino-4 ′-(N, N-dimethylamino) stilbene of the raw material monomer V in the evaporation source 25 is heated to 135 ° C. The shutter 28 was opened by heating, and a polyurea film having a stilbene structure with a thickness of 200 mm (0.02 μm) was deposited as a light emitting layer on the hole transport layer.
0076]
Next, Alq3 of the dye raw material T in the evaporation source 22b was heated to 280 [deg.] C. to open the shutter 27b, and an Alq3 film of 300 [mu] m (0.03 [mu] m) was deposited on the light emitting layer on the substrate 2 as an electron transport layer.
0077]
Subsequently, in the same manner as in Examples 1 and 2, a cathode and a polyurea protective film were formed on the electron transport layer on the substrate 2 to produce an organic EL device having a polyurea protective film.
0078]
When this organic EL device was driven under the conditions of a constant current density of 10 mA / cm 2, an initial luminance of 800 cd / m 2 and in the atmosphere, and the change with time was examined, the planar light emission of 350 cd / m 2 was maintained after 1000 hours.
0079]
Comparative Example 4
An organic EL device without a polyurea protective film was prepared according to Example 4 and was driven under the same conditions as in Example 4. When 30 hours later, the organic EL device was extinguished due to deterioration of the MgAg electrode.
0080]
In the above embodiment, the polyurea film serving as the polyurea protective film is formed by the vapor deposition polymerization method, but may be formed by a cast method or a spin coat method.
0081]
In the apparatus shown in FIG. 2, the oxygen plasma processing chamber 11, the organic compound film forming chamber 12, the cathode forming chamber 13, the protective film forming chamber 14, and the ultraviolet processing chamber 15 are made independent and juxtaposed. The entire apparatus is configured as a single vacuum apparatus, and an oxygen plasma processing chamber, an organic compound film forming chamber, a cathode forming chamber, a protective film forming chamber, and an ultraviolet processing chamber are included in the vacuum device. It is good also as an apparatus which accommodated and divided | segmented between each room by the partition wall which can be opened and closed freely.
0082]
In the above embodiment, the polyurea protective film is formed in the protective film forming chamber. However, the polyurea protective film may be formed in the organic compound film forming chamber 12.
0083]
Of course, oxygen plasma treatment of the substrate and ultraviolet irradiation treatment of the protective film can be performed in another chamber (vacuum treatment chamber).
0084]
When a conventional metal oxide such as CaO or MgO is used as a protective film for the cathode, it is necessary to heat the substrate to a temperature of 300 to 400 ° C. when forming the protective film in order to obtain a good protective film. In the present invention, since the polyurea protective film can be formed at room temperature, it is possible to greatly reduce the deterioration of the element due to the heat generation during the formation of the polyurea film.
0085]
【The invention's effect】
According to the method of manufacturing an organic electroluminescence device of the present invention, a polyurea protective film is formed on the cathode by a vapor deposition polymerization method, and then the polyurea film is irradiated with ultraviolet rays. Therefore, the polyurea film in the oligomer state can be cross-linked to be modified into a polymerized polymer film having excellent water resistance, heat resistance and durability with a network structure. There is an effect of providing a method by which a long-life organic electroluminescence element prevented by a protective film can be produced very easily.
In addition, since the polyurea protective film can be formed at room temperature, it is possible to greatly reduce the deterioration of the element due to heat generation during the formation of the polyurea film.
[Brief description of the drawings]
FIG. 1 is an explanatory side view of one embodiment of an organic electroluminescence device of the present invention,
FIG. 2 is an explanatory diagram of one embodiment of an apparatus for manufacturing an organic electroluminescence element of the present invention.
[Explanation of symbols]
1 organic electroluminescence device, 2 substrate,
3 anode, 4 hole transport layer (or light emitting layer),
5 light emitting layer (or electron transport layer), 6 cathode,
7 Polyurea protective film, 8 Extraction electrode,
11 oxygen plasma treatment chamber, 12 film formation chamber,
13 cathode forming chamber, 14 protective film forming chamber,
15 UV treatment chamber, 16 Gate valve,
17 Conveyance system, 18, 20, 31, 37, 45 Vacuum exhaust system,
19 RF electrode, 22a, 22b Dye evaporation source,
24, 25 Organic material evaporation source, 33, 34 Cathode material evaporation source,
39, 40 Protective film evaporation source, 46 UV lamp,
T dye raw material, U, V organic raw material monomer,
W, X Cathode raw material, Y, Z Protective film raw material monomer.

Claims (3)

The polyurea raw material monomer is evaporated in a vacuum, and this is vapor-deposited on the cathode of an organic electroluminescence device composed of an anode, an organic compound film and a cathode on the substrate to form a polyurea film, followed by vacuum. A method for producing an organic electroluminescence device, comprising forming a polyurea protective film by crosslinking the polyurea with ultraviolet irradiation in an atmosphere . Method of manufacturing an organic electroluminescent device of claim 1 wherein said organic compound film is characterized in that it is a film having at least a light emitting layer. The method for producing an organic electroluminescence device according to claim 1 or 2, wherein the polyurea raw material monomer is a diamine monomer and a diisocyanate monomer.

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