JP2012015241A - Organic electroluminescence element and production method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element and a production method for the same excellent in luminescence property, color temperature stability in luminance control and durability in long-time pulse drive luminescence; and to provide an organic EL element and a production method for the same by which an organic function layer is little damaged even in supercritical fluid treatment of an organic EL element formed on a flexible base plate.SOLUTION: An organic electroluminescence element has a first electrode, a second electrode and an organic function layer on a flexible base plate, in which the moisture content of the organic functional layer is 5 ppm or less with the oxygen molecule content 100 ppm or less.

Description

  The present invention relates to an organic electroluminescence element (hereinafter also referred to as an organic EL element) and a method for producing the organic EL element.

  In recent years, organic EL elements using organic substances have been promising for use as solid light-emitting inexpensive, large-area full-color display elements and writing light source arrays, and active research and development have been promoted. An organic EL element is a thin film composed of an organic functional layer (single layer portion or multilayer portion) having a thickness of only about 0.1 μm containing an organic light-emitting substance between a pair of anode and cathode formed on a film. Type all-solid-state device. When a relatively low voltage of about 2 to 20 V is applied to such an organic EL element, electrons are injected from the cathode and holes are injected from the anode into the organic compound layer. It is known that light emission can be obtained by releasing energy as light when the electrons and holes recombine in the light emitting layer and the energy level returns from the conduction band to the valence band. This technology is expected as a display and lighting. In addition, the recently discovered organic EL using phosphorescence emission can realize a luminous efficiency of about 4 times in principle compared to that using the previous fluorescence emission. Research and development of light-emitting element layer configurations and electrodes are performed all over the world.

  The organic EL element is required to remove as much moisture as possible from impurities in the organic functional layer due to its principle and dense structure. When they exist, it is known to cause a decrease in light emission luminance, a decrease in light emission efficiency, a deterioration in lifetime, a light emission defect (such as a dark spot), and the like (Non-patent Document 1, Patent Documents 1 to 3).

  Especially in the wet process method, when organic functional layer material is dissolved in a solvent and applied and laminated, it is extremely difficult to highly remove the slight moisture contained in the material and solvent, In addition, oxygen molecules adsorbed on the material or dissolved in the solvent remain in the formed organic functional layer. In particular, in the case of the phosphorescent light emitting type, it has been revealed that these deteriorate the color temperature stability when the luminance of the organic EL element is controlled and the durability in the pulse driving light emission for a long time.

  On the other hand, as a method for highly removing moisture, attempts have been made to remove moisture from organic EL materials and organic EL elements with a supercritical fluid (Patent Documents 4 and 5).

  However, when a normal organic EL device is treated with a supercritical fluid, not only the light emission characteristics are deteriorated, but also the organic functional layer structure is affected. In particular, an organic EL device formed on a flexible substrate is converted into a roll-to-roll method. It has also been found that there is a possibility that the organic functional layer may be damaged due to bending or a transport line when continuously producing in the process.

Japanese Patent Laid-Open No. 9-82474 JP-A-10-233283 US Pat. No. 6,633,121 JP 2001-255502 A JP 2005-285592 A

Supervised by Kiyozo Miyata, “Organic EL devices and their industrialization front”, NTS, November 1998

  The present invention has been made in view of the above problems, and its object is to provide an organic EL that has excellent light emission characteristics, color temperature stability in brightness control, and durability in pulse-driven light emission for a long time. It is providing the manufacturing method of an element and an organic EL element. Furthermore, the present invention also provides an organic EL element and an organic EL element manufacturing method in which the organic functional layer is less damaged even in the supercritical fluid processing of the organic EL element formed on a flexible substrate.

  The above object of the present invention is achieved by the following configurations.

  1. In an organic electroluminescence device having a first electrode, a second electrode and an organic functional layer on a flexible substrate, the water content of the organic functional layer is 5 ppm or less and the oxygen molecule content is 100 ppm or less. An organic electroluminescence element.

  2. 2. The organic electroluminescence device according to 1 above, wherein the glass transition temperature (Tg) of at least one layer of the organic functional layer is 140 ° C. or higher.

  3. 3. The organic electroluminescent element according to 1 or 2 above, wherein at least one of the organic functional layers contains a film reinforcing agent.

  4). 3. The organic electroluminescent element according to 1 or 2 above, wherein at least one of the organic functional layers is polymerized or crosslinked after forming the layer.

  5. Said 1st electrode has a conductive polymer layer, The organic electroluminescent element as described in any one of said 1-4 characterized by the above-mentioned.

  6). 6. The organic electroluminescence device as described in 5 above, wherein the first electrode further has a grid.

  7). 5. The organic electroluminescent element according to any one of 1 to 4, wherein the substrate is a flexible substrate and is a polyester film having a Tg of 80 ° C. or higher.

  8). In the manufacturing method of the organic electroluminescent element according to 1 to 7, the manufacturing method includes an atmospheric pressure process step, a high pressure process step, and a vacuum process step, and the high pressure process step is a step of performing supercritical fluid processing. A method for producing an organic electroluminescence device, comprising:

  9. Before the supercritical fluid processing step, a step of forming an organic functional layer having a Tg of 140 ° C. or higher is provided, and the step of forming the organic functional layer having a Tg of 140 ° C. or higher is a wet process. 9. The method for producing an organic electroluminescent element according to 8 above.

  10. 10. The method for producing an organic electroluminescent element according to 8 or 9, further comprising a process pressure substitution step before and after the supercritical fluid treatment step.

  11. 11. The method for producing an organic electroluminescent element according to any one of 8 to 10, wherein the supercritical fluid is supercritical carbon dioxide.

  12 12. The organic electroluminescence device according to 10 or 11, wherein the process pressure substitution step after the supercritical fluid treatment step is pressure substitution at a rate of 0.01 MPa / second to 0.5 MPa / second. Production method.

  According to the present invention, an organic EL element having excellent light emission characteristics and excellent durability in pulse-driven light emission for a long time can be provided, and a production method with improved productivity of the organic EL element can be provided. . In addition, according to the present invention, the organic functional layer can be continuously formed by a wet process, and the equipment cost, material cost, and production cost can be reduced.

It is a schematic diagram which shows an example of the process of producing an organic EL element. It is a schematic diagram which shows an example of a pressure substitution apparatus.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  In response to such issues, we are highly capable of removing moisture, removing oxygen molecules in the organic functional layer, and organic functions that can withstand supercritical fluid processing to remove moisture and oxygen molecules. By designing the layer, it has been found that not only the light emission characteristics but also the color temperature stability in luminance control and the durability in pulse-driven light emission for a long time are greatly improved, and the present invention has been achieved. .

  In the present invention, the water content of the organic functional layer of the organic EL element is 5 ppm or less, and the oxygen molecule content is 100 ppm or less. If the water content or oxygen molecule content exceeds this value, the luminous efficiency is lowered and the life is deteriorated. In order to set the moisture content of the organic functional layer to 5 ppm or less and the oxygen molecule content to 100 ppm or less, after applying with a coating solution in which the material constituting the organic functional layer is dissolved in a solvent, a high-temperature drying step is performed. Furthermore, it is preferable to perform a supercritical fluid treatment. The high temperature drying is preferably at least the boiling point of the solvent and below the glass transition temperature (hereinafter also referred to as Tg) of the organic functional layer.

  The supercritical fluid is described below.

  In the state diagram (phase diagram) of a substance, there is an end point on the high temperature and high pressure side of the evaporation curve, which is called a critical point, and there is a state where it is impossible to distinguish between liquid and vapor. A fluid that is above the critical temperature and above the critical pressure is called a supercritical fluid, and a temperature / pressure region that gives the supercritical fluid is called a supercritical region. A supercritical fluid is a high-density fluid having high kinetic energy, and as a solvent in a supercritical state, carbon dioxide, dinitrogen monoxide, ammonia, water, methanol, ethanol, 2-propanol, ethane, propane, butane, Hexane, pentane and the like are preferably used. Among them, carbon dioxide can be preferably used in the organic EL element of the present invention.

  The supercritical fluid treatment of the present invention is to immerse the organic functional layer on the flexible substrate in the supercritical fluid.

  When using a supercritical fluid of carbon dioxide, the fluid has a large diffusion coefficient in the supercritical region where the critical temperature (hereinafter also referred to as Tc) is 31 ° C. or higher and the critical pressure (hereinafter also referred to as Pc) is 7.4 MPa or higher. In addition, since the viscosity becomes small, mass transfer, concentration equilibrium is reached quickly, and the density is high like a liquid, the object to be removed or extracted is not limited to moisture and oxygen molecules by finely setting its temperature and pressure. You can choose variously.

  The use temperature of the supercritical fluid is not lower than the above critical temperature and basically not higher than the temperature at which the organic functional layer is softened, preferably not higher than Tg of the organic functional layer.

  The working pressure of the supercritical fluid is basically not limited as long as it is higher than the critical pressure of the substance to be used, but if the pressure is too low, the removal rate of moisture and oxygen molecules in the organic functional layer may be poor, If the pressure is too high, it is necessary to consider the durability of the manufacturing apparatus and the safety during operation. The working pressure is preferably 5 to 100 MPa.

  In the present invention, moisture can be removed to a high degree by performing supercritical fluid treatment on the organic functional layer of the organic EL element. In the present invention, the moisture content can be detected by analysis using TOF-SIMS (Time-of-flight secondary mass mass spectrometer).

  TOF-SIMS is a secondary ion mass spectrometry method for irradiating a solid sample with a primary ion beam and detecting ions (secondary ions) emitted from the outermost surface of the sample. It is a mass spectrometer that can measure chemical information of atoms and molecules with a sensitivity of one molecular layer or less, and can observe the distribution of specific molecules and atoms with a spatial resolution of 100 nm or less. Since TOF-SIMS has a high detection capability, in the present invention, the amount of water present in the organic functional layer can be sequentially measured from the surface of the organic functional layer to obtain a profile thereof.

  In addition, the moisture content can be accurately confirmed to a level of several ppm by comparing with the profiles of other elements whose coating amount is clear, so that the conditions for removing water in the supercritical fluid treatment can be set precisely.

  In the organic EL device of the present invention, the moisture content in the organic functional layer is 5 ppm or less. The lower limit is preferred. 0-3 ppm is preferable, and 0-1 ppm is more preferable.

  In the present invention, an organic electroluminescence device having a low water content and an oxygen molecule content of 100 ppm or less can be obtained, and excellent performance is exhibited.

  In the present invention, by performing supercritical fluid treatment on the organic functional layer of the organic EL element, not only can water be removed to a high degree, but also oxygen molecules adsorbed in the organic functional layer can be efficiently removed. it can.

  In this invention, the content rate of the oxygen molecule in an organic functional layer can be investigated by TOF-SIMS by the method similar to the said moisture content.

  That is, the amount of adsorbed oxygen molecules present in the organic functional layer is the balance obtained by subtracting the oxygen derived from the heavy water and the oxygen content of the oxygen-containing compound whose coating amount is obvious from the total oxygen amount detected in the organic functional layer. It is. For more accurate determination, it is preferable that all the materials used for forming the organic functional layer, including the solvent, contain no oxygen atoms. By this method, suitable conditions for removing oxygen molecules in supercritical fluid processing can be found.

  In the organic electroluminescent device of the present invention, the content of oxygen molecules in the organic functional layer is 100 ppm or less, preferably 0 to 30 ppm or less, and more preferably 0 to 20 ppm or less.

  In the present invention, in the process of supercritical fluid processing of the organic EL element, a process pressure substitution step is provided before and after the step, and the pressure applied to the organic functional layer is gradually changed to be present in the organic functional layer. It has been found that moisture and oxygen molecules can be efficiently removed.

  If this pressure change is abrupt, that is, after supercritical fluid treatment under pressure and then rapidly returning to atmospheric pressure, moisture and oxygen molecules adsorbed in the organic functional layer are not sufficiently removed. In addition, there is a possibility that it may affect the charge transport characteristics and light emission characteristics of the organic EL device, which may be due to changes in the coating film structure, and damage to the organic functional layer during process transportation. is necessary.

  In the present invention, the sample is lifted from the supercritical fluid, and from the pressurized state, a speed of 0.01 MPa / second to 0.5 MPa / second, preferably a speed of 0.01 MPa / second to 0.3 MPa / second, particularly It has been found that moisture and oxygen molecules can be effectively reduced without adversely affecting the organic functional layer, preferably by slowly returning to atmospheric pressure at a rate of 0.02 MPa / second to 0.2 MPa / second.

  In the process pressure replacement step in the present invention, it is preferable that the relationship of pressure with respect to time changes continuously, but a method in which a plurality of pressure levels change stepwise may be used.

  In the present invention, it is preferable that the organic functional layer can withstand supercritical fluid treatment, thereby not only improving the degree of freedom of the supercritical fluid treatment process, but also water and oxygen molecules in the organic functional layer. Can be efficiently removed.

  As a result of various studies so that the organic functional layer can withstand supercritical fluid treatment, it was found that it is effective to set the Tg of the organic functional layer to 140 ° C. or higher. This is because the organic functional layer has been found to have a resistance to pressure and heating conditions in the supercritical fluid treatment corresponding to Tg 140 ° C. of the organic functional layer. That is, when the Tg of the organic functional layer is 140 ° C. or more, it is preferable because the resistance in the supercritical fluid treatment is further improved. In order to set the Tg of the organic functional layer to 140 ° C. or higher, a material having a Tg of 140 ° C. or higher is selected to constitute the organic functional layer.

  The organic functional layer can also be supercritically treated by adding a film reinforcing agent to the organic functional layer, or by adding a polymerizable or crosslinkable material and subjecting it to polymerization or crosslinking treatment with heat or radiation. It can be made to withstand fluid processing. As a result, this method includes a case where the Tg of the organic functional layer corresponds to 140 ° C. or higher.

  The glass transition temperature Tg referred to in the present invention is measured at a rate of temperature increase of 20 ° C./minute using a differential scanning calorimeter (high-sensitivity differential scanning calorimeter EXSTAR DSC 6220 manufactured by SII NanoTechnology Co., Ltd.). And the midpoint glass transition temperature determined according to JIS K 7121 (1987). The organic functional layer to be described later can be measured after forming the coating film individually.

  Tg in the present invention is defined by actual measured values. Organic conception, Yoshio Koda, Shiro Sato, Yoshio Honma, “New edition organic conception diagram Basics and Application”, Sankyo Publishing (2008) The approximate Tg can also be estimated using the relationship.

  In the present invention, the organic functional layer may have a Tg of 140 ° C. or higher, but two or more layers are preferably Tg 140 ° C. or higher, and all layers are most preferably Tg 140 ° C. or higher.

  In the present invention, it is effective to contain a film reinforcing agent in the organic functional layer so that the organic functional layer can withstand supercritical fluid processing.

  The film reinforcing agent used in the present invention refers to a material that improves damage to a coating film that occurs when the organic functional layer of an organic EL element is treated with a supercritical liquid, and includes a material that exhibits this effect.

  The film reinforcing agent used in the invention is preferably an alkali metal salt of an organic acid. There are no particular restrictions on the type of organic acid salt, but formate, acetate, propionic acid, butyrate, valerate, caproate, enanthate, caprylate, oxalate, malonate, succinate Acid salt, benzoate, phthalate, isophthalate, terephthalate, salicylate, pyruvate, lactate, malate, adipate, mesylate, tosylate, benzenesulfonate Preferably, formate, acetate, propionate, butyrate, valerate, caprate, enanthate, caprylate, oxalate, malonate, succinate, benzoate, More preferred are alkali metal salts of aliphatic carboxylic acids such as formate, acetate, propionate, butyrate, etc., and the aliphatic carboxylic acid preferably has 4 or less carbon atoms. Most preferred is acetate.

  The kind of alkali metal of the alkali metal salt of the organic acid is not particularly limited, and examples thereof include Na, K, and Cs, preferably K, Cs, and more preferably Cs. Examples of the alkali metal salt of an organic acid include a combination of the above organic acid and alkali metal, and preferably, formic acid Li, formic acid K, formic acid Na, formic acid Cs, acetic acid Li, acetic acid K, Na acetate, Cs acetate, propionic acid Li, Na propionate, propionate K, propionate Cs, oxalate Li, oxalate Na, oxalate K, oxalate Cs, malonic acid Li, malonate Na, malonic acid K, malonic acid Cs, succinic acid Li, Succinic acid Na, succinic acid K, succinic acid Cs, benzoic acid Li, benzoic acid Na, benzoic acid K, benzoic acid Cs, more preferably Li acetate, K acetate, Na acetate, Cs acetate, most preferably Cs acetate .

  The content of the film reinforcing agent may be adjusted by addition amount, and is preferably 1.5 to 35% by mass, more preferably 3 to 25% by mass, and most preferably 5 to 15% by mass with respect to the functional layer. It is. Although the action of the alkali metal salt of the organic acid on the organic functional layer is not clear, it is presumed to be an orientation or crystallization effect of the organic compound. It has been confirmed that by adding an alkali metal salt of an organic acid to the organic functional layer, the shearing force is improved as compared with an unadded layer.

  The effect of the film reinforcing agent can be confirmed by improving the shearing force as follows. That is, an organic EL element sample to which a film reinforcing agent is added and an organic EL element sample that does not contain a film reinforcing agent are prepared, and each uses a die plow intes cycas NN-04 type hardness tester (SAICAS), Measure the shear force of the membrane. As measurement conditions, the sampling step was 0.2 sec / point, a diamond 1 mm wide blade was used, the shear angle was 45 °, the pressing load was 2 μN, the balance load was 1 μN, the vertical speed was 1 nm / sec, and the horizontal speed was 100 nm. Cutting is performed at / sec, the horizontal and vertical forces are recorded, and the horizontal and vertical shear forces are recorded.

  In the film reinforcing functional layer in the present invention, it is preferable that the average of the shearing force in the horizontal direction and the vertical direction of the functional layer is increased by 1.2 times or more by adding the film reinforcing agent, and is increased by 1.3 times or more. More preferably, it is most preferably increased by 1.5 times or more.

  We have found that such an alkali metal salt of an organic acid is effective as a countermeasure against damage to the organic functional layer coating film caused by supercritical fluid treatment. It is one of preferred embodiments to apply an alkali metal salt of an organic acid to the present invention as a film reinforcing agent.

  In the present invention, it is sufficient that at least one of the organic functional layers contains a film reinforcing agent, but it is preferable that two or more layers contain a film reinforcing agent, and all the layers contain a film reinforcing agent. Most preferably. If it is a highly diffusible film strengthening agent, even if it is added to at least one of the organic functional layers, an excellent effect is exhibited.

  In the present invention, in addition to adding a film reinforcing agent to the organic functional layer, the organic functional layer material is provided with a substituent that can be polymerized and cross-linked by heat or radiation. Also effective is a method of improving the resistance of the organic functional layer in the supercritical liquid treatment by polymerizing and crosslinking with radiation.

  For example, the organic functional layer material is an organic compound having a reactive substituent described in claim 4 of International Publication No. 2007/148649.

  In the case of polymerization or crosslinking by heat, heating with a hot plate, microwave irradiation, irradiation with an infrared lamp, circulation of a heated inert gas, and the like can be mentioned. In the case of polymerization or crosslinking by radiation, irradiation with ultraviolet rays, X-rays, laser light or the like can be mentioned. Among them, ultraviolet irradiation is easy to adjust and effective, and in particular, ultraviolet irradiation using converters, DC power supply type ultraviolet irradiation devices, light emitting diodes, and electrodeless ultraviolet irradiation devices have little fluctuation in irradiation energy. Therefore, it is preferable because of the effect of increasing the uniformity of the organic functional layer. Particularly preferably, ultraviolet irradiation and heat treatment are used in combination.

  In the present invention, at least one layer of the organic functional layer may be made of a material having a substituent capable of polymerization and crosslinking, but it is preferably used for two or more layers, and may be used for all layers.

  The electrodes of the organic EL element make a pair and are called first and second electrodes. In the present invention, the first and second electrodes correspond to an anode and a cathode, respectively.

  In the present invention, the surface of a conventional metal oxide electrode layer represented by ITO (Indium Tin Oxide) is affected by the supercritical fluid treatment, and organic It turned out that the fall of the luminescent property seen by the fall of adhesiveness with a functional layer is caused.

  As a result of diligent improvement, it has been found that an electrode layer having a conductive polymer layer, preferably an electrode layer having a conductive polymer layer and a grid, has resistance to supercritical fluid treatment, and prevents a decrease in light emission characteristics. I found it.

  As a conductive polymer used for the conductive polymer layer of the present invention, a π-conjugated conductive polymer is preferable. The π-conjugated conductive polymer is not particularly limited, but polythiophenes and polyanilines are preferable from the viewpoint of conductivity, transparency, stability, and the like. Most preferred is polyethylene dioxythiophene.

  A more preferable conductive polymer layer in the present invention comprises a π-conjugated conductive polymer and a polyanion.

  The polyanion is preferably composed of a structural unit having an anionic group and a structural unit having no anionic group. The polyanion preferably has a function of solubilizing the π-conjugated conductive polymer in a solvent. The anionic group of the polyanion preferably functions as a dopant for the π-conjugated conductive polymer to improve the conductivity and heat resistance of the π-conjugated conductive polymer.

  The anionic group of the polyanion may be any functional group that can undergo chemical oxidation doping to the π-conjugated conductive polymer. Among them, from the viewpoint of ease of production and stability, a monosubstituted sulfate group A monosubstituted phosphate group, a phosphate group, a carboxy group, a sulfo group and the like are preferable. Furthermore, from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer, a sulfo group, a monosubstituted sulfate group, and a carboxy group are more preferable.

  Moreover, the polyanion which has a fluorine (F) in a compound may be sufficient. Specifically, Nafion (manufactured by Dupont) containing a perfluorosulfo group, Flemion (manufactured by Asahi Glass Co., Ltd.) made of perfluoro vinyl ether containing a carboxylic acid group, and the like can be mentioned.

  Among these, when the compound having a sulfo group is formed by applying and drying the conductive polymer-containing layer, the heat treatment is performed at a temperature of 100 ° C. or more and 200 ° C. or less for 5 minutes or more. It is more preferable because the cleaning resistance and solvent resistance of the coating film are remarkably improved.

  Furthermore, among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethylsulfonic acid, and polyacrylic acid butylsulfonic acid are preferable. These polyanions have high compatibility with the binder resin, and can further increase the conductivity of the obtained conductive polymer.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  A commercially available material can be preferably used for such a conductive polymer. For example, a conductive polymer (abbreviated as PEDOT-PSS) composed of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is described in H.C. C. It is commercially available from Starck as the Clevios series, from Aldrich as PEDOT-PSS 483095, 560596, and from Nagase Chemtex as the Denatron series. Polyaniline is also commercially available from Nissan Chemical as the ORMECON series. In the present invention, such a material can also be preferably used.

  In the present invention, the grid is installed for the purpose of reducing the internal resistance of the light transmissive electrode. In the present invention, the grid is particularly laminated on a conductive polymer layer and used as an auxiliary electrode. Therefore, a metal is preferable as a material.

  The shape of the metal grid pattern is not particularly limited, and may be, for example, a stripe shape, a lattice shape, or a random network structure, but the aperture ratio is preferably 80% or more from the viewpoint of transparency. The aperture ratio is a ratio of the portion without the thin lines forming the metal grid pattern to the whole. For example, the aperture ratio of the striped grid pattern having a line width of 100 μm and a line interval of 1 mm is approximately 90%.

  The line width of the metal grid pattern is preferably 10 to 200 μm from the viewpoint of conductivity and transmittance. The height of the fine wire (thickness of the conductive metal layer) is preferably 0.1 to 10 μm from the viewpoints of conductivity, current leakage prevention, and fine wire distribution uniformity.

  There is no restriction | limiting in particular as a method of forming a metal grid pattern, A conventionally well-known method can be utilized. For example, the ink containing metal fine particles can be formed by a method of printing in a desired shape by a known printing method such as gravure printing, flexographic printing, offset printing, screen printing, and inkjet printing.

  As another method, a metal layer is formed on the entire surface of the substrate and formed by a known photolithographic method, a method of performing plating after printing a catalyst ink that can be plated in a desired shape, and another method include A method using silver salt photography technology can also be used. In addition, a method using silver salt photographic technology can be carried out with reference to paragraph number 0076-0112 of JP-A-2009-140750 and examples.

  The surface specific resistance of the thin wire portion of the first conductive layer is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The surface specific resistance can be measured according to, for example, JIS K 6911, ASTM D257, etc., and can be easily measured using a commercially available surface resistivity meter.

  In the present invention, it is preferable to use a conductive polymer layer and an electrode layer having a grid, since the resistance to supercritical fluid treatment is improved and the deterioration of light emission characteristics can be effectively prevented.

  As described above, in order to improve the resistance to supercritical fluid processing, which is extremely effective in improving the performance of organic EL elements, the Tg of the organic functional layer is set to 140 ° C. or higher, or the organic functional layer is strengthened. It can be seen that it is important to add an agent for strengthening treatment, to use a polymerizable or crosslinkable material, and to use an electrode having a conductive polymer layer and a grid.

  An important point in supercritical fluid processing is to maintain a speed of 0.01 MPa / second to 0.5 MPa / second when replacing pressure from a pressurized state to an atmospheric pressure state after supercritical fluid processing. However, if the organic EL element has been improved as described above, the degree of freedom of supercritical fluid processing is improved, so that it can be applied to wet process production and roll-to-roll production.

  The basic configuration of the organic EL element in the present invention will be described.

<< Configuration of organic EL element >>
The organic EL element of the present invention has a first and second electrodes and an organic functional layer sandwiched between both electrodes on a substrate. Specific examples thereof include the following.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / electron transport layer / electron injection Layer / cathode (iv) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode (v) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection Layer / cathode (vi) anode / hole injection layer / hole transport layer / blue light emitting layer / green light emitting layer / red light emitting layer / electron transport layer / electron injection layer / cathode In the organic EL device of the present invention, a blue light emitting layer In the case of / green light emitting layer / red light emitting layer, the light emitting maximum wavelength of the blue light emitting layer is preferably from 430 nm to 480 nm, the green light emitting layer has a light emitting maximum wavelength of 510 nm to 550 nm, and the red light emitting layer has a light emitting maximum wavelength. A monochromatic light emitting layer in the range of 600 nm to 640 nm is preferred. . Further, at least three light emitting layers may be arbitrarily mixed to form a white light emitting layer composed of 1 to 3 layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  The organic functional layer in the present invention means a hole injection layer, a hole transport layer, a light emitting layer (including a blue light emitting layer, a green light emitting layer, and a red light emitting layer), an electron transport layer, and an electron injection layer.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 500 nm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 10 nm to 20 nm.

  For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can.

  The light emitting layer of the organic EL device of the present invention preferably contains a host compound and at least one kind of light emitting dopant (such as a phosphorescent dopant (also referred to as a phosphorescent dopant) or a fluorescent dopant).

(Host compound)
The host compound used in the present invention will be described.

  Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of light emission dopants mentioned later, and, thereby, arbitrary luminescent colors can be obtained.

  Further, the host compound used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and one kind of low molecular compound having a polymerizable group such as a vinyl group or an epoxy group may be used. Multiple types may be used.

(Luminescent dopant)
The luminescent dopant will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent light-emitting dopant) or a phosphorescent dopant (also referred to as a phosphorescent dopant or a phosphorescent light-emitting dopant) can be used, and an organic EL element with higher emission efficiency is obtained. From the viewpoint, it is preferable that the light emitting layer and the light emitting unit of the organic EL device of the present invention contain the above-mentioned host compound and at the same time contain a phosphorescent dopant.

(Phosphorescent dopant)
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescence at room temperature (25 ° C.) and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II of “Experimental Chemistry Course 7”, 4th edition, Maruzen, page 398 (1992 edition). Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. The energy transfer type that obtains light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

  The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  The phosphorescent dopant is preferably a complex compound having a transition metal element of group 8 to group 10 as the central metal in the periodic table, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), Rare earth complexes, most preferably iridium compounds.

  Specific examples of preferred phosphorescent dopants in the present invention include compounds of paragraph numbers 0137 to 0154 of JP2008-159741, compounds of paragraph numbers 0105 to 0110 of JP2008-181937, and JP2010-49818A. The compounds 1-1 to 1-110 and the compounds of paragraph numbers 0149 to 0153 described in the above can be preferably used. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  Next, an injection layer, a transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

《Electron injection layer, hole injection layer》
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) ) ”, Chapter 2,“ Electrode Material ”(pages 123 to 166) in detail, and includes a hole injection layer (also referred to as an anode buffer layer) and an electron injection layer (also referred to as a cathode buffer layer). There is.

  The details of the hole injection layer are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, a phthalocyanine buffer represented by copper phthalocyanine And an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the electron injection layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specifically, metals represented by strontium, aluminum and the like. Examples thereof include a buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, the hole injection layer is also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, the electron injection layer is also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, an electron transport layer having a high n-type semiconductor property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use such an electron transport layer having a high n-type semiconductor property because an element with lower power consumption can be produced.

<First electrode>
The first electrode in the present invention is an anode, and as the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials generally include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. In the present invention, as described above, In the case of supercritical liquid treatment, it is preferable to use an electrode having a conductive polymer and a grid as the anode.

《Second electrode》
On the other hand, the second electrode in the present invention is a cathode, and the cathode uses a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material. Is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured. Also in the case of a cathode, an electrode having a conductive polymer and a grid can be used.

《Flexible substrate》
The substrate of the organic EL element is a flexible substrate that is flexible in the present invention and is suitable for continuous production by a roll-to-roll method. A resin film is particularly preferable.

  The flexible substrate that can be used in the organic EL device of the present invention is not particularly limited in the type of resin or the like, and may be transparent or opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. A transparent resin film can be mentioned as a transparent flexible substrate preferably used.

  Preferred transparent resin films include, for example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, and cellulose acetate propionate (CAP). ), Cellulose esters such as cellulose acetate phthalate (TAC), cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone , Polyimide, polyethersulfone (PES), polyphenylene sulfide, poly Cycloolefins such as sulfones, polyether imides, polyether ketone imides, polyamides, fluororesins, nylon, polymethyl methacrylate, acrylics or polyarylates, Arton (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals) Based resins and the like.

  As a particularly preferable transparent resin film, a resin film having a Tg of 80 ° C. or higher is preferable, and 100 ° C. or higher is particularly preferable. Specifically, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, polyimide, and polyamide. In relation to the Tg of the organic functional layer, when the difference in Tg value is within 60 ° C., preferably within 40 ° C., resistance to supercritical fluid processing is improved and film peeling due to bending of the organic EL element It contributes to the improvement of the service life in high temperature atmosphere.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a polymer plate / film, a metal plate / film, and the like. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has a water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by a method according to JIS K 7129-1992, 1 × 10 ⁻⁶ g. / (M ² · 24h) or less, preferably the oxygen permeability measured by a method in accordance with JIS K 7126-1987 is 1 × 10 ⁻³ ml / (m ² · 24h · MPa) or less. .

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. .

  In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen molecules. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. Can do.

  Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In this invention, it is preferable to maintain in the atmosphere with a moisture content of 1 ppm or less from the process of the supercritical fluid treatment to the sealing process.

  A method for manufacturing an organic EL element will be described.

  As an example of the method for producing an organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described. Basically, the method includes a step of forming a first electrode on a substrate, a step of forming an organic functional layer having a Tg of 140 ° C. or higher, a step of supercritical fluid treatment, and a step of forming a second electrode. preferable.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate so as to have a thickness of 1 μm or less, preferably 10 nm to 200 nm, to form an anode.

  Next, organic compound thin films such as a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, which are organic EL element materials, are formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, in the present invention, a wet process in which a material is dissolved or dispersed in a solvent and a film is formed by a coating method is preferable. As a specific wet process, a spin coating method, an ink jet method, a printing method, a die coating method or the like is preferable. In addition, since the present invention effectively removes moisture and oxygen molecules mixed in the material and solvent, it is highly effective in a wet process.

  Examples of the solvent for dissolving or dispersing the organic EL material include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, mesitylene, cyclohexyl benzene, and the like. Aromatic hydrocarbons, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used. Two or more of these may be mixed and used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, a thin film made of a cathode material is formed thereon by 1 μm or less, preferably by a method such as vapor deposition or sputtering so that the film thickness is in the range of 50 nm to 200 nm. By providing, a desired organic EL element can be obtained.

  The film thickness of the organic EL element and each organic functional layer is required to be about 0.05 to 0.3 μm, and preferably about 0.1 to 0.2 μm.

  In the present invention, an organic compound having a reactive group (reactive organic compound) may be used in each functional layer. There is no restriction | limiting in particular as a layer using a reactive organic compound, It can use for each layer. An organic material having a function having a reactive group in each functional layer may be used.

  After forming the reactive organic compound coating layer, it is allowed to react on the substrate to form a network polymer of organic molecules, which can be cured. The formation of the network polymer is preferable because the Tg of the constituent layer can be increased.

  It is also possible to change the emission wavelength of the organic EL element, suppress deterioration of the specific wavelength, etc. by adjusting the reaction accompanied by the cleavage or generation of the conjugated system of the molecule using the active radical in use. is there.

  On the other hand, on the manufacturing side, for example, in the case of a step of laminating by coating, it is preferable that the lower layer does not dissolve in the upper layer coating solution. Therefore, the upper layer can be applied by resinating the lower layer and degrading solvent solubility. be able to. For example, when the hole transport layer is resinized as an organic layer thus crosslinked, dissolution and penetration of the lower layer can be prevented when the light emitting layer is applied as the upper layer.

  Although it does not specifically limit as a reactive group which can be used, For example, a vinyl group, an ethynyl group, an isocyanate group, an epoxy group etc. are mentioned typically.

  As described above, after the Tg of the organic functional layer is set to 140 ° C. or higher, the above-described supercritical fluid treatment is preferably performed. After the supercritical fluid treatment, the above-described electron injection layer is provided if necessary, and a cathode of a pair of electrodes is further provided.

  The characteristics of the organic EL device manufacturing method of the present invention are characterized by an atmospheric pressure process step for treating a flexible substrate under an atmospheric pressure environment, a high pressure process step for treating the flexible substrate under a high pressure environment, and a flexible under vacuum environment. A high-pressure process step is a step of supercritical fluid processing. More preferably, among the above steps, there is a process pressure replacement step of replacing the process pressure of each step between the atmospheric pressure process step and the high pressure process step and between the high pressure process step and the vacuum process step. It is a manufacturing method of an organic EL element.

  A known process pressure displacement step can be performed using a pressure displacement device. There are two types of pressure displacement devices. First, as shown in, for example, Japanese Patent Laid-Open No. 8-27574, a band-shaped flexible substrate (web) passes through a plurality of pseudo-enclosed spaces whose pressures are adjusted in stages. In other words, the pressure displacement speed can be changed by changing the web conveyance speed. Second, for example, as shown in Japanese Patent Application Laid-Open No. 2010-62012, in a chamber equipped with a sandwiching type gate valve, the gate valve sandwiches the web in a state where the web is introduced. Once formed, this is done by converting the process pressure by adjusting it with a pump, and the pressure displacement rate can be changed directly by the pump.

  In the present invention, a sandwich type gate valve is used as a process pressure replacement step for introducing from an atmospheric pressure process step (atmospheric pressure environment) to a high pressure process step (high pressure environment) and vice versa. The preferred pressure displacement device is preferred. Based on a clamp system that secures the pressure of the space (chamber) formed by the gate valve after the part of the longitudinal direction of the web is sandwiched from above and below using the gate valve across the entire width. It is. At that time, the conveyance is stopped at the portion sandwiched by the gate valve, and the conveyance is intermittent here. Therefore, it is preferable to use an accumulator together. When the conveyance is stopped, the web can be continuously accumulated as a system in which the web is accumulated in the accumulator, and when the gate valve is opened, this is sent to the higher pressure side of the next process, for example.

  In the production method of the present invention, in the hole injection layer (atmospheric pressure process), the hole transport layer (atmospheric pressure process), the light emitting layer (atmospheric pressure process), the electron transport layer (atmospheric pressure process), in the process pressure substitution step Pressurize, supercritical fluid treatment (high pressure process), depressurize in process pressure replacement step to return to atmospheric pressure, form electron injection layer and cathode (vacuum process), pressurize in process pressure replacement step, return to atmospheric pressure Based on that.

  The pressurization in the process pressure replacement step toward supercritical fluid treatment is performed by injecting carbon dioxide gas when the supercritical fluid treatment is a carbon dioxide fluid with respect to nitrogen gas or an inert gas atmosphere at normal pressure. It is preferable to apply pressure. After the supercritical fluid treatment, the pressure is slowly reduced to atmospheric pressure, and further reduced to vacuum to form an electron injection layer and a cathode, and then returned to normal pressure with a nitrogen bath or an inert gas and sealed. Is done.

In the present invention, the atmospheric pressure process step is about 0.1 MPa, the high-pressure process step of supercritical fluid treatment is 5 MPa or more, and the vacuum process step is 1 × 10 ⁻³ Pa or less.

  By pulling up the sample from the supercritical fluid and slowly returning it from the pressurized state to atmospheric pressure at a rate of 0.01 MPa / second to 0.5 MPa / second, without affecting the organic functional layer and the electrode, Oxygen molecules can be effectively reduced.

(Use)
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Although it is not limited to this, it can be effectively used particularly as a backlight of a liquid crystal display device combined with a color filter and a light source for illumination.

  In the organic EL device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. Although it is mentioned, it is not limited to these, It can apply widely.

<Roll-to-roll: Production line>
Next, manufacturing by the roll-to-roll method will be described.

  Compared to the sheet method, the roll-to-roll method is advantageous in terms of high-speed continuous production, and achieves an increase in production volume and cost reduction.

  Basically, a step of feeding a belt-like flexible substrate (web) wound in a roll shape to form at least a first electrode on the web, a step of forming an organic functional layer having a Tg of 140 ° C. or higher, supercriticality A preferable organic EL device of the present invention can be produced by the step of fluid treatment, the step of forming an electron injection layer, and the step of forming a second electrode. The whole process may be manufactured on one continuous production line, or after the production on the first production line having at least two continuous processes, the remaining one is wound into a roll and the rest The manufacturing method manufactured with the 2nd manufacturing line which has a process may be sufficient.

  FIG. 1 is a schematic view showing an example of a process for producing an organic EL element. In addition, the description of the manufacturing process shown in this drawing is a case where a first electrode, a hole transport layer, a light emitting layer, an electron injection layer, a second electrode, and a sealing film are pasted on a belt-like flexible substrate as an example of an organic EL element. This is performed in the case of an organic EL element for illumination (surface emission) in which each layer is formed in the order of. In this figure, the first electrode forming step is omitted.

  In FIG. 2, 2a shows the manufacturing process of an organic EL element. The manufacturing process 2 a includes a strip-shaped flexible substrate supply process 3, a hole transport layer forming process 4 for forming a hole transport layer, a light emitting layer forming process 5 for forming a light emitting layer, and an electron transport layer forming process 6. ing.

  In this example, after the electron transport layer is formed, the belt-shaped flexible substrate is once wound up in the winding portion 7.

  In FIG. 1, in the manufacturing process 2b, the band-shaped flexible substrate once formed in the manufacturing process 2a after the formation of the electron transport layer is further subjected to supercritical fluid processing 9, electron injection from the supply unit 8 of the band-shaped flexible substrate. An electron injection layer forming step 10 for forming a layer, a second electrode forming step 11 for forming a second electrode, and a sealing layer forming step 12 for forming a sealing layer are wound up as an organic EL element, Thereafter, cutting is performed, individual elements are formed, an electric circuit is mounted, and an organic electroluminescence panel is formed.

  In the manufacturing apparatus shown in the figure, the supply process 3 to the light emitting layer formation process 5 and the electron transport layer formation process 6 are continuously performed under atmospheric pressure conditions. Shows a case where the process is performed under a high pressure condition, and the process from the electron injection layer forming process 10 to the second electrode forming process 11 is performed under a reduced pressure condition. The sealing layer forming step 12 is under reduced pressure conditions or inert gas filling conditions.

  In the supply process 3 of the strip-shaped flexible substrate, the feeding unit 301 and the surface treatment unit 302 are provided. In the feeding unit 301, for example, the strip-shaped flexible substrate A in which the gas barrier film and the anode layer including the first electrode are already formed in this order is supplied in a roll state wound around the winding core. 3a1 shows the former roll of a strip | belt-shaped flexible substrate.

The surface treatment unit 302 includes a cleaning surface modification processing apparatus and antistatic means, but the antistatic means is omitted here. The cleaning surface modification processing apparatus performs cleaning modification on the surface of the first electrode (not shown) of the strip-shaped flexible substrate A sent from the supply step 3 before the organic functional layer application, for example, a low pressure mercury lamp, an excimer lamp, For example, in the case of a low-pressure mercury lamp, a low-pressure mercury lamp having a wavelength of 184.2 nm is irradiated at an irradiation intensity of 5 to ²⁰ mW / cm ² and a distance of 5 to 15 mm.

  Further, the antistatic means includes a non-contact type static elimination prevention device, a contact type static elimination prevention device, and the like, and is performed using, for example, a non-contact type ionizer, a static elimination roll or a conductive brush connected to the ground. The non-contact type antistatic device is preferably used on the first electrode surface side of the strip-shaped flexible substrate A, and is preferably used on the back surface side of the contact-type antistatic device strip-shaped flexible substrate A.

  Although these details are omitted in the figure, the strip-shaped flexible substrate A is unwound from the roll and enters the hole transport layer forming step.

  In the hole transport layer forming step 4, a backup roll 4a for holding the strip-shaped flexible substrate A, and a first wet coater for applying a coating solution for forming a hole transport layer to the strip-shaped flexible substrate A held by the backup roll 4a 4b, a first drying device 4c for removing the solvent of the hole transport layer formed on the first electrode on the strip-shaped flexible substrate A, and a first heat treatment device for heating the hole transport layer from which the solvent has been removed 4d. Here, an antistatic means may be provided, but it is omitted in the figure.

  The coating liquid for forming a hole transport layer by the first wet coater 4b is applied on the first electrode except for, for example, a part of one end of the already formed first electrode.

  The first wet coater 4b applies the light emitting layer on the first electrode in accordance with the pattern of the first electrode formed by patterning. For example, an inkjet method, a flexographic printing method, an offset printing method, Various coating apparatuses used for a gravure printing method, a screen printing method, a spray coating method using a mask, and the like can be used.

  The first drying device 4c is a drying processing device that removes the solvent by a heated airflow. For example, the height is 100 mm from the ejection port of the slit nozzle type toward the film formation surface, the ejection air velocity is 1 m / s, and the width. Carry out with a hand distribution of 5% and a drying temperature of 100 ° C.

  The heat treatment apparatus 4d is a back surface heat transfer type heat treatment apparatus that heats the hole transport layer from the back surface side of the belt-like flexible substrate by the back surface heat transfer method, for example, has a plurality of heating rollers at 200 ° C., for example, After the removal, a heat roll having a temperature of 200 ° C. is sucked from between closely arranged rolls, the substrate is sucked and conveyed, and heat treatment is performed by heating by back surface heat transfer. By this heat treatment, smoothness of the film, removal of residual solvent, curing of the coating film, and the like are performed.

  Next, in the light emitting layer forming step 5, the second wet coater 5b for applying the light emitting layer forming coating solution to the belt-shaped flexible substrate having the hole transport layer held by the backup roll 5a, and the hole transport layer It has a drying device 5c for removing the solvent of the formed light emitting layer, and a heat treatment device 5d for heating the light emitting layer from which the solvent has been removed. Again, the same antistatic means as described above may be used, but is omitted.

  The second wet coater 5b is preferably of the same type as the first wet coater 4b.

  The drying device 5c has the same structure as the drying device 4c. The heat treatment apparatus 5d has the same structure as the first heat treatment apparatus 4d, and heats the light emitting layer formed on the hole transport layer from the back surface side of the belt-shaped flexible substrate by the back surface heat transfer method. Yes.

  After the light emitting layer forming step 5, the electron transport layer coating step 6 is entered.

  In the electron transport layer forming step 6, a third wet coater 6b for applying a coating liquid for forming an electron transport layer to a belt-like flexible substrate having a hole transport layer and a light emitting layer held by a backup roll 6a, A drying device 6c for removing the solvent of the electron transport layer formed on the substrate, and a heat treatment device 6d for heating the electron transport layer from which the solvent has been removed. Similarly, an antistatic means may be used.

  The hole transport layer forming step 4, the light emitting layer forming step 5 and the electron transport layer forming step 6 shown in this figure show the case where there is one wet coating device, a drying device and a heat treatment device, respectively. It is possible to increase according to. Further, when further increasing the organic functional layers such as the hole injection layer and the electron injection layer, the wet coating apparatus, the same as the exemplified hole transport layer forming step 4, the light emitting layer forming step 5, and the electron transport layer forming step 6, It is preferable to form a coating film of the organic functional layer in a process including a drying device and a heat treatment device.

  A belt-like flexible substrate in which each layer of the organic functional layer is formed in the winding unit 7 is referred to as a belt-like flexible substrate 7g (hereinafter, belt-like flexible substrate B) wound around the core with the organic functional layer side inside.

  Moreover, you may provide the process of wiping off the unnecessary part about the formed organic functional layer using the solvent etc. which can melt | dissolve each layer before winding up. As the wiping process, for example, there are a belt-like wiping device described in Japanese Patent Application No. 2008-17776, a device using a blade, etc., and using these, the alignment mark formed on the belt-like flexible substrate in advance is used. Wipe according to position. A continuous wiping method is preferable, and when carrying out wiping in the width direction by stopping conveyance, an accumulating mechanism or the like is provided on the front and rear sides to continuously perform from application to winding of the organic functional layer.

  In this way, the layers up to the electron transport layer are formed on the strip-shaped flexible substrate. Next, the strip-shaped flexible substrate B is in the process 9 for supercritical fluid treatment.

  After forming the electron transport layer, step 9 may be performed in which the material is continuously wound up and sent to the manufacturing step 2b to perform supercritical fluid processing. In this case, the winding portion does not need to be provided, and an accumulating mechanism is provided between the organic functional layer coating formation speed and a buffer region for adjusting intermittent conveyance during the formation of the electron injection layer. Thus, it can be sent to the step 9 for continuous supercritical fluid treatment.

  In FIG. 2, supercritical fluid treatment, formation of an electron injection layer and a second electrode, and further sealing are performed on the band-shaped flexible substrate once wound up by the manufacturing process 2 b.

  The supercritical fluid processing step 9 is a high-pressure process step, and the electron injection layer forming step 10 and the second electrode forming step 11 for forming the second electrode are vacuum process steps. The injection layer forming step 10 and the second electrode forming step 11 will be described by performing vacuum deposition.

  In the manufacturing process 2b, the strip-shaped flexible substrate B after the electron transport layer is formed is supplied from the supply unit 8 to the process 9 for supercritical fluid processing performed under the high pressure. Although the process 9 for supercritical fluid processing is performed under high pressure, since the supply unit 8 is at atmospheric pressure, a process pressure replacement process is necessary here.

  The process pressure replacement step is a process of replacing pressures among the three processes of the atmospheric pressure process step, the high pressure process step, and the vacuum process step. In the present invention, the process pressure replacement step uses a chamber equipped with a sandwich type gate valve, and the gate valve sandwiches the strip-shaped flexible substrate in a state where the belt-like flexible substrate is introduced into the chamber to form a pseudo sealed space. In the case of a vacuum process from the space, it is configured by reducing and maintaining the space sealed by the sandwiching type gate valve by exhausting with a vacuum pump. On the contrary, in the case of a high-pressure process, a space sealed by a sandwiching gate valve is pressurized and maintained by pressurizing with a pump.

  The process pressure replacement step basically includes a sandwiching gate valve and a chamber (buffer chamber) opened and closed by the sandwiching gate valve. The pressure in the chamber sealed by the sandwiching gate valve is reduced or increased by a pump. In order to make adjustments, sandwiched gate valves are provided at the entrance and exit of a chamber (buffer chamber) through which the belt-shaped flexible substrate is transported.

  In the manufacturing process 2b, the supply unit 8 enters the process 9 in which the strip-shaped flexible substrate B performs a supercritical fluid treatment through the buffer chamber provided with the sandwiching type gate valve. In this example, two chambers each provided with sandwiched gate valves G1, G2, and G3 as buffer chambers are provided in succession (Ch1, Ch2), and the process pressure is adjusted in multiple stages. In this buffer chamber, in the supercritical fluid processing step 9, in order to ensure high pressure, the sandwiching gate valve is closed at the valve position, the conveyance of the flexible substrate is stopped, and pressurization is performed for continuous pressurization. An accumulator mechanism is provided inside the chamber for buffering the transportation and stop of the belt-like flexible substrate B to be transported.

  As shown in the schematic diagram, the accumulator mechanism is composed of a dancer roller for applying a constant tension.

  In the process indicated by 2b in FIG. 2, the process pressure replacement process is composed of a sandwiching gate valve G1, a chamber Ch1, a sandwiching gate valve G2, a chamber Ch2 and a sandwiching gate valve G3, and the degree of pressurization is determined in two stages. Can be adjusted. The sandwich type gate valves G1 to G3 are provided so as to be connected to the inlet of the chamber Ch1, the connecting portion of Ch1 and Ch2, and the outlet side of the chamber Ch2, that is, the inlet of the process 9 for supercritical fluid processing. Of course, the chamber Ch1 and the chamber Ch2 can be independently evacuated by a pump. In addition, although it is a two-stage configuration here, it may be provided in multiple stages of three or more stages in order to perform the required degree of pressurization and efficient conveyance.

  The flexible substrate unwound from the supply unit is conveyed to the chamber Ch1 through the open sandwiching gate valve G1, while the sandwiching gate valve G2 is closed. Therefore, the flexible substrate is placed in the chamber Ch1 by the accumulator mechanism. Accumulated in.

  When a predetermined amount of the flexible substrate is conveyed, the sandwiching gate valve G1 is closed, the transportation of the flexible substrate unwound from the supply unit is stopped, and the chamber Ch1 closed by the sandwiching gate valves G1, G2 is pressurized. And high pressure. At that time, the chamber Ch2 (with the sandwiching gate valve G3 closed) is also pressurized and kept at a high pressure. When the chamber Ch1 is pressurized and is in a high pressure state, the sandwiching gate valve G2 is opened, and a predetermined amount of the flexible substrate is transferred to the chamber Ch2 in the high pressure state. Further, when the predetermined amount is transferred, the sandwiching gate valve G2 is closed, and a predetermined amount is accumulated in the chamber Ch2 by an accumulator mechanism provided in the chamber Ch2. Next, the sandwiching type gate valve G3 that constitutes a connecting portion with the step 9 of supercritical fluid processing (pressurized to a high pressure) is opened, and then a predetermined amount of the flexible substrate accumulated in the chamber Ch2 It is sent to step 9 where the critical fluid is processed. Here, the sandwiching type gate valve G3 is also closed, the conveyance is stopped, and the supercritical fluid processing is performed. During this time, a predetermined amount of flexible substrate is transferred from the chamber Ch1 to the chamber Ch2 by opening the sandwiching gate valve G2.

  During this time, the chambers Ch1 and Ch2 are maintained so as to maintain a predetermined pressure.

  The treatment of the organic functional layer in the step 9 of performing the supercritical fluid treatment is preferably carried out by being immersed in the supercritical fluid 9c in the container 9b for a predetermined time so as to be continuously conveyed and supercritical fluid treated. Supercritical fluid processing can be performed by conveying the supercritical fluid c hermetically sealed by the container 9b, the hermetic roller 9d, and the immersion roller 9a for a predetermined time. By further providing an accumulator mechanism before and after the supercritical fluid treatment, the stop at the gate valve can be preferably absorbed.

  After a predetermined amount of flexible substrate is transferred from the chamber Ch1 by opening the sandwiching gate valve G2, the sandwiching gate valve G2 is closed, and further, the sandwiching gate valve G1 is opened and the decompression of the chamber Ch1 is released. Then, a predetermined amount of the flexible substrate is transferred into the chamber Ch1 with an accumulator mechanism. After the predetermined amount of the flexible substrate is transferred into the chamber, the sandwiching gate valve G1 is closed again, the transfer from the supply unit is temporarily stopped, and the chamber Ch1 is pressurized again with a pump to a high pressure.

  Here, the chamber Ch1 and the chamber Ch2 can be pressurized by a pump, the chamber Ch1 connects the chamber Ch2 and the supply unit 8 (atmospheric pressure), and the chamber Ch2 is supercritical fluid treated with the chamber Ch1. The pressure can be adjusted step by step.

  The accumulator mechanism provided in each chamber appropriately has a buffer function so that the flexible substrate can be smoothly transported from the chamber Ch2 to the electron injection layer forming unit 9 and from the chamber Ch1 to the chamber Ch2.

  In this manner, the process pressure can be smoothly changed from the atmospheric pressure to the high pressure state by repeatedly carrying out the respective operations of conveyance and accumulation by a predetermined sequence in a predetermined sequence.

  Here, the process pressure replacement step is directly entered from the supply unit 8. However, if a similar accumulator mechanism is installed between the supply unit and the process pressure replacement step, the winding from the supply unit 8 can be performed without intermittent transfer. The dispensing can be performed continuously.

  When returning from the high pressure state to the atmospheric pressure, the method opposite to the pressurization may be performed. After reaching the same pressure as that in the step 9 in which the chamber Ch3 is subjected to the supercritical fluid treatment, the gate valve G4 is opened, the web subjected to the supercritical fluid treatment is conveyed to the chamber Ch3, and then the gate valve G4 is closed and decompressed at a predetermined speed. be able to. Further, the number of accumulators or the number of chambers can be increased and the pressure can be reduced after the chamber Ch4.

  The electron injection layer forming step 10 and the second electrode forming step 11 are vacuum processes, and can be brought into a vacuum state through the process pressure replacement step described above.

  The electron injection layer forming step 10 and the second electrode forming step 11 are the same vacuum process step. Here, in order to be able to adjust the difference in vapor deposition rate, each of the electron injection layers is injected into the same vacuum chamber via an accumulator mechanism. Two vapor-deposited portions that are the layer forming step and the second electrode forming step 11 are provided. When the belt-shaped flexible substrate B is transported from the chamber Ch4 through the sandwiching gate valve G6, when the electron injection layer forming portion is fixed to the support holder and stationary in the electron injection layer forming step 10, the sandwiching gate valve G6 is Then, the evaporation source boat is heated and mask evaporation is performed. In the electron injection layer forming step 10, an electron injection layer is formed on the electron transport layer in the electron injection layer forming portion, where 10b is a support holder of a vapor deposition apparatus, and 10a schematically shows an evaporation source container. .

  Also in the second electrode formation step 11, when the formation site is fixed to the support holder and is stationary, the second electrode is similarly formed on the electron injection layer in the second electrode formation portion (vapor deposition apparatus). In the vapor deposition apparatus, reference numeral 11b denotes a support holder, and 11a denotes an evaporation source container.

  Here, the strip-shaped flexible substrate B on which the electron injection layer is formed is configured to be sent to the second electrode forming step 11 via an accumulator mechanism.

  The strip-shaped flexible substrate on which the second electrode is formed is subsequently sent to the sealing layer forming step 12.

  The sealing layer forming step 12 is preferably sealed in an inert gas atmosphere such as a rare gas or nitrogen gas in order to keep harmful components to a minimum. Therefore, after the second electrode forming step, the sealing layer forming step A similar process pressure replacement step is used to perform 12 continuously.

  That is, the sandwiched gate valve G7 is opened from the second electrode forming step 11 which is a deposition step into the chamber Ch5 which is evacuated to a reduced pressure and high vacuum with the sandwiched gate valve G7 and G8 closed, and the second electrode is formed by deposition. After a predetermined amount of the flexible substrate formed with is conveyed, the sandwiching gate valve G7 is closed. The sandwiching type gate valve G8 is closed during conveyance, but a predetermined amount of a flexible substrate on which the second electrode is formed is stored in the chamber Ch5 by an internal accumulator mechanism. Next, the sandwiched gate valve G8 is opened at the connecting portion with the chamber Ch6 that is closed by the sandwiched gate valves G9 and G8 and previously exhausted to a reduced pressure, and a flexible substrate is accumulated in the chamber Ch6 by a predetermined amount.

  Next, after closing the sandwiching type gate valve G8, the sandwiching type gate valve G9 is opened and, for example, in the sealing layer forming step 12 maintained in a nitrogen gas atmosphere, a predetermined amount of the belt-like band formed up to the second electrode is formed. Send flexible substrate B. In this state, the chamber Ch6 has a nitrogen atmosphere. After a predetermined amount of the belt-like flexible substrate is sent to the sealing layer forming step 12, the sandwiched gate valve G9 is closed again (conveyance stopped), and the chamber Ch6 is evacuated by evacuation by evacuating again with the pump. To do.

  In this way, by intermittently transporting by a predetermined amount, the process pressure in the electron injection layer forming step 10 and the second electrode forming step 11 is maintained at a vacuum while the process pressure is atmospheric pressure from the flexible substrate supply unit. The organic electroluminescence element can be produced by roll-to-roll.

  The sealing layer forming step 12 is a sealing film sticking step. In the sealing film sticking step, when a predetermined amount of the belt-like flexible substrate B is supplied through the sandwiching gate valve G9, the belt-like flexible substrate B is applied. The adhesive is applied by a coating device for applying the adhesive on the second electrode, and is bonded to the sealing film at the bonding portion constituted by the pressure-bonding roll 12b2, and further is cured (not shown in the figure). Are cured and sealed and sealed. During this period, the belt-like flexible substrate B and the sealing film are conveyed by a predetermined amount, but the sandwiching gate valve G10 is closed, and the conveyance is absorbed by the accumulator mechanism while the nitrogen atmosphere is maintained. After a predetermined amount of the sealing film is laminated, the conveyance is stopped, and after the sandwiching gate valve G9 is closed, the sandwiching gate valve G10 is opened, and the sealing film adhering step 12 is opened. A sealed organic EL element laminated with the sealing film is taken out. After the predetermined amount is taken out, the sandwiching gate valve G10 is closed again, and nitrogen filling is performed again to restore the nitrogen atmosphere.

  In this example, the adhesive is applied on the second electrode of the strip-shaped flexible substrate B, but may be applied on the sealing film.

  Note that the curing processing unit is made of, for example, an ultraviolet lamp or the like, and is arranged for ultraviolet irradiation when a photo-curable adhesive or the like is used.

  Although the sealing layer forming step 12 has been described as an atmospheric pressure process step in a nitrogen atmosphere in the above, sealing may be performed in a vacuum, for example. In this case as well, it can be controlled in a similar manner by a process pressure replacement step comprising a plurality of chambers equipped with a sandwich type gate valve.

  After the sealing layer forming step 12, the belt-like flexible substrate on which the organic EL element whose sealing has been completed is formed by the winding unit and the sealing film is attached may be wound up once.

  The wound strip-shaped flexible substrate C (illumination (surface emitting) organic EL element) wound up has an oxygen concentration of 1 to 100 ppm and a moisture concentration of 1 to 100 ppm in consideration of performance maintenance, dark spots (non-light emitting portions), and the like. It is preferable to store in the environment.

  Moreover, you may perform the continuous flexible film cutting process which cuts the organic electroluminescent element produced by the continuous flexible film into a product size, without winding up, following a sealing film bonding process. In FIG. 2, reference numeral 13 denotes a cutting process. Using the punching and cutting machine 13a, the alignment mark attached to the PET is detected, and the product size is punched and cut by a cutter according to the position of the alignment mark. 13b schematically represents a punching and cutting machine. The continuous flexible film after the organic EL element is punched is then wound into a roll by a winder.

  Next, the sandwiching type gate valve used in the process pressure replacement step will be described.

  As a typical conductance type vacuum valve, a mechanism that obtains a vacuum by the conductance of this part by installing nip rolls in multiple stages has been researched for a long time, but most of them require contact with the processed surface. There are many applications to no product line. When applied to product lines where contact with the processed surface is a problem, such as organic EL, it is necessary to make the gap as narrow as possible while maintaining a non-contact state, and damage to the processed surface due to meandering, etc. At the same time, a highly accurate conveyance technique that is suppressed as much as possible is required.

  The sandwiching gate valve used in the present invention is preferably a system in which the entire width or a part of the film is clamped by the valve. More specifically, it is a vacuum gate valve that opens and closes an opening located between the vacuum side and the atmosphere side by a valve body, and the valve body is a deformable ring-shaped elastic valve body, and an actuator that drives the elastic valve body The opening is opened and closed by deformation. The elastic valve body is composed of an upper valve member and a lower valve member, and has an upper presser member and a lower presser member that are moved in opposite directions by a drive actuator. The upper presser member is connected to the upper valve member, and the lower presser member is The structure is connected to the lower valve member, and the elastic valve body is made of rubber. The material of the elastic body is desirably rubber, but among the rubber, fluororubber having a low gas permeability is suitable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
Three units of a low density layer, a medium density layer, a high density layer, and a medium density layer made of silicon oxide are formed on both surfaces of a polyethylene terephthalate film (PET film) having a width of 700 mm and a thickness of 180 μm by an atmospheric pressure plasma discharge treatment method. By laminating, a transparent gas barrier layer having a total thickness of 90 nm was formed.

As a result of measuring the water vapor permeability by a method based on JIS K 7129-1992, it was 1 × 10 ⁻⁶ g / (m ² · 24 h) or less.

As a result of measuring oxygen permeability by a method based on JIS K 7126-1987, it was 1 × 10 ⁻³ ml / (m ² · 24 hr · MPa) or less.

<Preparation of sample 101>
(Creation of ITO anode)
An original roll is introduced into one surface of the PET film into a roll-to-roll vacuum chamber, and a 130 nm ITO film is formed in an argon atmosphere using a sputtering apparatus to form a transparent conductive film as an anode. did. The surface resistivity of the ITO film was 40Ω / □.

<Preparation of hole injection layer>
A solution of polyethylene dioxythiophene / polystyrene sulfonate (PEDOT / PSS, Baytron PAI 4083 manufactured by Bayer) replaced with heavy water and a small amount of acetonitrile added to the surface of the sample on which the anode as the first electrode was formed. Got ready.

  Next, as a coating machine, a pre-metering type coating apparatus (slit coater) that continuously discharges the coating liquid from the slit shown in FIG. 6A of JP-A-2009-268975 is used. After applying at a rate of 100 minutes per minute, the drying apparatus removes the solvent at a height of 100 mm from the slit nozzle type discharge port toward the film formation surface, a discharge air speed of 1 m / s, a wide wind speed distribution of 5%, and a temperature of 120 ° C. Then, heat treatment of the back surface heat transfer method was performed at a temperature of 150 ° C. by a heat treatment apparatus, and a hole injection layer having a thickness of 30 nm after drying was formed.

<< Preparation of hole transport layer >>
Next, on the hole injection layer, a coating solution for a hole transport layer in which 2.0 g of the following compound HT-1 (Tg 97 ° C.) is dissolved in 400 ml of acetonitrile is applied in accordance with JIS B 9920 under a nitrogen atmosphere. It was applied with a slit coater similar to the above under the conditions of measured cleanliness of class 100, dew point temperature of −80 ° C. or lower, and oxygen concentration of 0.8 ppm or lower. After coating, the substrate was heated and dried at a substrate surface temperature of 150 ° C. for 30 minutes to provide a hole transport layer having a dry film thickness of 20 nm.

<Production of light emitting layer>
Next, 4.0 g of the following Host-1 (Tg132 ° C.), 0.60 g of D-1, 0.08 g of D-2, and D-3 as a coating solution for the light emitting layer are formed on the hole transport layer. Was dissolved in 400 g of toluene and coated with the same slit coater under the same conditions as in the preparation of the hole transport layer. After coating, the substrate was heated at a substrate surface temperature of 120 ° C. for 30 minutes to obtain a light emitting layer having a dry film thickness of 40 nm.

<< Production of electron transport layer >>
Next, on the light emitting layer, 3.0 g of ET-1 (Tg 114 ° C.) below as an electron transport layer coating solution is dissolved in 400 g of acetonitrile, and the same slit is formed under the same conditions as the formation of the hole transport layer. It was applied with a coater. After coating, the substrate was heated at a substrate surface temperature of 120 ° C. for 30 minutes to provide an electron transport layer having a dry film thickness of 30 nm.

<Preparation of Samples 102 to 104>
Next, in sample 101, HT-1 is changed to HT-2 (Tg 146 ° C.), Host-1 is changed to Host-2 (Tg 143 ° C.), and ET-1 is changed to ET-2 (Tg 195 ° C.). A sample 102 was prepared in the same manner except that the sample 102 was replaced with. Note that the Tg of the light-emitting layer of the sample 102 was 140 ° C. or higher.

  Further, Sample 103 was prepared in the same manner as Sample 101 except that HT-1 was replaced with HT-3 and ET-1 was replaced with ET-3 with the same molar amount. However, after coating the hole transport layer, UV irradiation is performed for 50 seconds using an electrodeless UV irradiation device (Fusion UV Systems Japan Co., Ltd., Light Hammer 6) while heating the substrate at 130 ° C. went. Similarly, after the electron transport layer was coated, the ultraviolet irradiation treatment was performed.

  Further, Sample 104 was prepared in the same manner except that 0.70 g of cesium acetate as a film reinforcing agent was added to the coating solution for the electron transport layer when forming the electron transport layer of Sample 101.

<Supercritical fluid processing>
The samples 101 to 104 that have already been formed up to the electron transport layer are cut into a size of 150 mm × 150 mm for experiments, and placed in a pressure displacement device (FIG. 2) to be pressurized and heated from atmospheric pressure (8.0 MPa, 35 ° C. ), Dipped in a supercritical carbon dioxide fluid, pulled up, and then returned from the pressure heating state to the room temperature and atmospheric pressure state.

  The flexible substrate having the organic functional layer is subjected to supercritical fluid processing in the supercritical processing step. The supercritical fluid processing will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing an example of a pressure displacement device. The sample formed up to the electron transport layer is cut into a size of 150 mm × 150 mm for experiment, the gate A201 is opened, and the sample is stored in the holder 204 in the pressure adjustment chamber 203. After closing the gate A201, repeated pressure reduction and pressurization with a pump (not shown) connected to the valve A205 and the valve A205, and after changing from atmospheric pressure to a pressurized heating state (8.0 MPa, 35 ° C.) with nitrogen gas, The gate B202 is opened, and the sample is stored by operating the hand 209 on the arm 208 in the processing unit 211 in the processing chamber 207 (8.0 MPa, 35 ° C.) pressurized through the valve B206 with a pump (not shown). Then, the lid of the processor 211 was closed. Thereafter, the carbon dioxide introduced from the cylinder 217 is pressurized by the pressurizer 212 (8.0 MPa, 35 ° C.) and introduced as the supercritical fluid 210 into the processor 211 via the valve D216, and the sample is immersed for a predetermined time. did. Thereafter, the pressure was reduced at a constant speed by operating the valve C215 and the pressure reducer 213. At this time, the pressure in the processing chamber was similarly reduced. After returning to atmospheric pressure, the arm 208 and the hand 209 were operated to take out the sample from the processor 211 to the outside.

  At this time, a pressure change from a pressurized state to an atmospheric pressure state performed at a speed of 1.0 MPa / second is defined as Condition A, and samples subjected to supercritical fluid treatment under the conditions are denoted as 101A to 104A. The sample carried out at a rate of 2 MPa / second was defined as Condition B, and samples subjected to supercritical fluid treatment under the conditions were defined as 101B to 104B.

<< Production of Electron Injection Layer and Cathode >>
Samples 101A to 104A and 101B to 104B that were provided up to the electron transport layer and were treated with the supercritical carbon dioxide fluid were placed in a nitrogen atmosphere with a moisture content of 1 ppm or less without being exposed to the atmosphere, and then moved to a vapor deposition machine. The pressure was reduced to 4 × 10 ⁻⁴ Pa.

  Potassium fluoride and aluminum are put in a resistance heating boat made of tantalum and attached to a vapor deposition machine. First, as an electron injection layer formation, the resistance heating boat containing potassium fluoride is energized and heated to fluorinate on the substrate. An electron injection layer made of potassium was provided at 3 nm. Subsequently, as a cathode formation, a resistance heating boat containing aluminum was energized and heated, and a cathode having a film thickness of 100 nm made of aluminum was provided at a deposition rate of 1 to 2 nm / second.

<Sealing>
Each sample prepared up to the cathode was measured in accordance with JIS B 9920 under a nitrogen atmosphere with a moisture content of 1 ppm or less under atmospheric pressure. The measured cleanliness was class 100, the dew point temperature was −80 ° C. or less, and the oxygen concentration was 0. A sealing member in which a thermosetting liquid adhesive (epoxy resin) is applied to a thickness of 30 μm on one side of an aluminum foil having a thickness of 100 μm in the sealing step is transferred to an atmospheric pressure process of .8 ppm or less. Then, the adhesive surface of the sealing member and the organic functional layer surface of the element are continuously overlapped so that the end portions of the extraction electrodes of the first electrode and the second electrode of the element are exposed, and adhesion is performed by a dry laminating method. It was.

  In addition, the description regarding formation of the lead-out wiring from an anode and a cathode is abbreviate | omitted.

<Evaluation>
About the obtained organic EL element samples 101A-104A and 101B-104B, the moisture content and the oxygen-containing molecular rate were obtained by the profile analysis method of the “TOF-SIMS”.

  In addition, the light emission efficiency, the light emission lifetime, and the driving voltage were determined for the organic EL element samples 101A to 104A and 101B to 104B. Furthermore, the chromaticity variation at the time of light control and pulse driving stability were also evaluated.

(Luminescence efficiency)
The organic EL device sample was measured for emission luminance when a constant current of ^2.5 mA / cm ² was applied at room temperature (about 23 to 25 ° C.) using CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.) and taken out from the outside. The quantum efficiency was defined as the luminous efficiency. It represented with the relative value which sets the luminous efficiency of 101 A of organic EL elements to 1.0.

(Luminescent life)
The organic EL element sample is continuously lit at room temperature under a constant current condition with a direct current with an initial luminance of 1,000 cd / m ^2, and the time (τ _1/2 ) required to obtain half the initial luminance is obtained. It was measured. The light emission lifetime was expressed as a relative value where the light emission lifetime of the organic EL element 101A was 1.0.

(Drive voltage)
The organic EL element was turned on at room temperature under a constant luminance condition of 1,000 cd / m ² , and the drive voltage immediately after the start of lighting was measured. The drive voltage is expressed as a relative value where the drive voltage of the organic EL element 101A is 1.0. In addition, it is preferable for energy saving that a drive voltage is low, Therefore, it shows that it is excellent, so that a relative value is small.

(Chromaticity variation during dimming)
The organic EL element is driven at a room temperature at a luminance of 200 cd / cm ² to 5,000 cd / cm ² , and the linear distance on the coordinates represented by the chromaticity x value and y value therebetween, that is, the chromaticity variation width The absolute value was measured. It is preferable that the chromaticity fluctuation range at the time of dimming is small, and even if the brightness of the organic EL illumination is adjusted, the illumination color is stable, which means that color rendering can be maintained.

(Pulse drive stability)
The organic EL element is continuously lit at an initial luminance of 1,000 cd / m ² at a room temperature by applying a driving voltage by a pulse driving method, and a time required to obtain half the initial luminance (τ _1/2 ) Was measured to evaluate pulse drive stability. In the pulse driving method, a pulse voltage having a frequency of 60 Hz and a duty ratio of 10% was applied to the organic EL element. The pulse-driven light emission lifetime was expressed as a relative value with the light emission lifetime of the organic EL element 101A as 1.0. In the following table, it was abbreviated as pulse life.

  The evaluation results are shown in Table 1.

  From the results of 101A to 104A, when removing moisture and oxygen molecules by supercritical fluid treatment, the effect is greatly increased by using a material having a high Tg for the organic functional layer, polymerization crosslinking, or using a film reinforcing agent. It can be seen that the performance is improved. Furthermore, it can be seen from the comparison between 101A to 104A and 101B to 104B that the effect is remarkably improved by slowly performing pressure replacement after the supercritical fluid treatment.

(Example 2)
The effect which changed the anode from the ITO type | mold to what consists of a grid and a conductive polymer was confirmed.

<Formation of grid>
Adv. Mater. , 2002, 14, 833 to 837, by using PVP K30 (molecular weight 50,000; manufactured by ISP), silver nanowires having an average minor axis of 75 nm and an average length of 35 μm were produced. The silver nanowires are filtered and washed with a filtration membrane, and then redispersed in a heavy aqueous solution in which 25% by mass of hydroxypropylmethylcellulose 60SH-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) is added to the silver. Prepared.

The prepared silver nanowire dispersion liquid was applied to one surface of the PET film using an extrusion coater so that the weight of the silver nanowires was 50 mg / m ² and dried. Subsequently, the silver nanowire coating layer was calendered, and then a 10 mm square grid transparent pattern was formed by photolithography to form a grid.

<Formation of conductive polymer layer>
On the grid, PEDOT-PSS CLEVIOS PH510 (solid content 1.89%) (manufactured by HC Starck) was applied to a dry film thickness of 150 nm and dried to form a conductive polymer layer. .

<Formation of hole injection layer to electron transport layer>
Samples 201A to 204A and 201B to 204B were prepared in the same manner as the samples 101A to 104A and 101B to 104B of Example 1 except that the anodes were different.

  The evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

  <Result>

  From the above results, when the ITO electrode is changed to a grid and conductive polymer, the effect of removing moisture and oxygen molecules by supercritical fluid treatment is improved, especially the color temperature stability of organic EL elements. It can be seen that the characteristics and pulse stability are improved.

(Example 3)
In order to evaluate roll-to-roll production suitability, the following bending resistance tests were performed on the obtained samples.

<Bending resistance>
With respect to each of the produced organic EL elements, the operation of bending and extending so that the light emission surface is inward, the bending angle is 90 degrees, and the bending radius is 2 cm is 100 times at a rate of once every 2 seconds in an inert gas atmosphere. Repeated times. The light emitting state after the bending and stretching test was visually observed, and the following ranking was performed. The obtained results are shown in Table 2.

6: Uniform light emission with no bright spots or black spots 5: 1 to 2 bright spots or black spots are observed, but stable light emission is observed 4: About 5 bright spots or black spots are observed, and light emission luminance Slightly unstable 3: About 7 to 8 bright spots or black spots are observed, and the emission luminance is further unstable 2: Exceeding 10 bright spots or black spots, the emission luminance is very unstable. 1: No light emission The results obtained are shown in Table 3.

  From the above results, it can be seen that the configuration of the present invention has high bending resistance, and therefore has high roll-to-roll production suitability. Furthermore, what changed to the electrode which consists of a grid and a conductive polymer is still more excellent, and what implemented the pressure substitution rate in a supercritical fluid process on specific conditions has shown the outstanding resistance. According to the present invention, it can be seen that the flexible organic EL element can be developed for various uses.

2a, 2b Manufacturing process 3 Supply process 4 Hole transport layer forming process 5 Light emitting layer forming process 6 Electron transport layer forming process 7 Winding part 8 Supplying part 9 Supercritical fluid processing process 10 Electron injection layer forming process 11 Second electrode Formation process 12 Sealing layer formation process 201 Gate A
202 Gate B
203 Pressure adjusting chamber 204 Holder 205 Valve A
206 Valve B
207 Processing chamber 208 Arm 209 Hand 210 Supercritical fluid 211 Processor 212 Pressurizer 213 Decompressor 214 Separation tank 215 Valve C
216 Valve D
217 cylinder

Claims (12)

  In an organic electroluminescence device having a first electrode, a second electrode and an organic functional layer on a flexible substrate, the water content of the organic functional layer is 5 ppm or less and the oxygen molecule content is 100 ppm or less. An organic electroluminescence element.   The organic electroluminescence device according to claim 1, wherein a glass transition temperature (Tg) of at least one layer of the organic functional layer is 140 ° C or higher.   The organic electroluminescent device according to claim 1, wherein at least one of the organic functional layers contains a film reinforcing agent.   The organic electroluminescent device according to claim 1 or 2, wherein at least one of the organic functional layers is polymerized or crosslinked after forming the layer.   The organic electroluminescence device according to any one of claims 1 to 4, wherein the first electrode has a conductive polymer layer.   The organic electroluminescence element according to claim 5, wherein the first electrode further has a grid.   The organic electroluminescent element according to claim 1, wherein the substrate is a flexible substrate and is a polyester film having a Tg of 80 ° C. or higher.   8. The method of manufacturing an organic electroluminescence device according to claim 1, wherein the manufacturing method includes an atmospheric pressure process step, a high pressure process step, and a vacuum process step, and the high pressure process step performs a supercritical fluid process. The manufacturing method of the organic electroluminescent element characterized by the above-mentioned.   Before the supercritical fluid processing step, a step of forming an organic functional layer having a Tg of 140 ° C. or higher is provided, and the step of forming the organic functional layer having a Tg of 140 ° C. or higher is a wet process. The manufacturing method of the organic electroluminescent element of Claim 8 characterized by the above-mentioned.   10. The method of manufacturing an organic electroluminescence element according to claim 8, further comprising a process pressure substitution step before and after the step of performing the supercritical fluid treatment.   The method for producing an organic electroluminescent element according to any one of claims 8 to 10, wherein the supercritical fluid is supercritical carbon dioxide.   12. The organic electroluminescence device according to claim 10, wherein the process pressure substitution step after the supercritical fluid treatment step is pressure substitution at a rate of 0.01 MPa / second to 0.5 MPa / second. Manufacturing method.

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