KR102228341B1 - Method for recovering material for organic electroluminescent device and method for manufacturing material for organic electroluminescent device - Google Patents

Abstract

In the method for recovering a material for an organic electroluminescent device of the present invention, a mixture containing a plurality of types of materials for an organic electroluminescent device is recovered by a supercritical or subcritical chromatography method, and a plurality of active ingredients Get

Description

Method for recovering material for organic electroluminescent device and method for manufacturing material for organic electroluminescent device

The present invention relates to a method for recovering a material for an organic electroluminescent device and a method for producing a material for an organic electroluminescent device. In particular, the material for an organic electroluminescent device is efficiently obtained from a film forming device such as a mask. The present invention relates to a method for recovering a material for an organic electroluminescent device, which can be recovered, and the recovered material is applicable to an organic electroluminescent device, and a method for producing a material for an organic electroluminescent device.

Electronic devices using organic compounds, for example, organic electroluminescent diodes (also referred to as "OLED" and "organic EL devices"), organic photoelectric conversion devices, and various electronic devices such as organic transistors have been developed. In addition, according to their technological progress, distribution in various industrial and market fields is proceeding.

For example, organic EL devices, which are typical examples of organic electronic devices, have begun to be used in various fields such as displays, lighting, and indicators, and have already penetrated into the present life together with liquid crystal displays or light emitting diodes (LEDs). Therefore, it is going to reach a period of exponential expansion in the future.

However, in order to promote the development of organic electronic devices such as organic EL elements, a number of problems to be solved in the process of research and development remain. In particular, various problems resulting from the use of organic compounds remain common to various organic electronic devices or as peculiar problems. These problems to be solved can be said to be the ultimate problems directly connected to further improvement in performance such as quantum efficiency and light emission life, and further improvement in productivity, that is, cost reduction.

Among the ultimate challenges above, regarding the performance issues, in terms of electronic displays, organic EL elements are already being used in the main display of smartphones, and that large displays exceeding 50 inches are becoming products and are coming out on the market. Also in signage, the luminous efficiency of 139Lm/W in white devices, which is about twice that of fluorescent lamps, is achieved, but with red phosphorescent devices and green phosphorescent devices, the luminance half-life of 1 million hours has been achieved. Since the result of exceeding 100,000 hours is also being produced even in a difficult blue phosphorescent element, it is thought that the level sufficient for practical use has already been reached by performing a film formation with elaborate and detailed layer structure and careful attention.

On the other hand, regarding the problem of productivity, that is, cost, there is still a lot of room for improvement.

Organic electroluminescence is self-luminous, and since the luminous color is uniquely determined as a light-emitting material constituting the light-emitting layer, it is basically red (Red: R), green (Green: G), and blue (Blue: B). A method (RGB side-by-side method) is employed in which organic EL elements of respective luminous colors are produced for each pixel, and arrayed to form a display. In the case of depositing a film using the RGB side-by-side method, since each pixel is formed while subtly shifting the shadow mask, components other than the portion corresponding to the pixel remain on the shadow mask. In addition, in order to prevent contamination of the inside of the evaporation apparatus, a barrier plate is generally provided, and materials that do not reach a pixel are deposited on a member such as a shadow mask, a barrier plate, or a shutter.

In view of the above problems and circumstances, in the case of fabricating an organic EL device by a vapor deposition method, various studies have been conducted in order to improve the utilization efficiency of materials (see, for example, Patent Document 1).

In Patent Document 1, the purpose of separating, recovering, and reusing an organic material attached to a shadow mask or the like by sublimating in a vacuum is disclosed. However, it is known that the performance of the organic EL device is greatly affected by the purity of the material, and it is known that a very small amount of impurities adversely affects the performance. Patent Document 1 discloses that it is also possible to purify by a sublimation method, but when removing a very small amount of impurities generated in the evaporation process and obtaining a single component from a plurality of components, the sublimation method is a purification method from the viewpoint of the degree of purification. Is not enough.

In addition, in order to improve the purity of a material, a supercritical chromatography method is known as a method with a high number of theoretical plates (for example, see Patent Document 2). According to Patent Document 2, it is disclosed that the performance of the device is improved by purifying the organic EL material by a purification method having a step of bringing the organic EL material into contact with a supercritical or subcritical solvent. However, the method disclosed here is only used for purification of synthetic materials, and no mention is made of the effectiveness of the material recovered from the film forming apparatus.

Japanese Patent Publication No. 2014-29844 Japanese Patent Application Publication No. 2005-02257

The present invention has been made in view of the above problems and conditions, and the problem to be solved is that the material for an organic electroluminescent element can be efficiently recovered from a film forming apparatus such as a mask, and the recovered material can be used as an organic electroluminescent element. It is to provide a method for recovering a material for an organic electroluminescent device applicable to the method, and a method for producing a material for an organic electroluminescent device.

In order to solve the above problems, the inventors of the present invention, in the process of examining the cause of the above problem, etc., use a mixture containing a plurality of active ingredients, which are materials for organic electroluminescence devices, by supercritical or subcritical chromatography. Efficiency of use of organic materials by recovering and reusing organic materials, for example, attached to a mask, other than organic materials that are deposited on a substrate and usefully used as a light emitting layer by separating and purifying by a method and obtaining a plurality of active ingredients It was found that can be increased, and came to the present invention. In addition, since the supercritical or subcritical chromatography method is a purification method with a very high number of theoretical plates, it is possible to remove a very small amount of impurities, and the material recovered by the method can be applied to an organic electroluminescent device. Found that there is.

That is, the said subject concerning this invention is solved by the following means.

1. A method for recovering a material for an organic electroluminescent device in which a mixture containing a plurality of types of materials for an organic electroluminescent device is recovered by a supercritical or subcritical chromatography method to obtain a plurality of active ingredients.

2. The method for recovering the material for an organic electroluminescent device according to claim 1, wherein the difference in molecular weight between any two materials for an organic electroluminescent device contained in the mixture is 200 or more.

3. The method for recovering the material for an organic electroluminescent device according to claim 1 or 2, wherein the mixture contains at least one organic compound and at least one organometallic complex.

4. The method for recovering the material for an organic electroluminescent device according to claim 3, wherein the organic metal complex is a phosphorescent dopant containing iridium (Ir) or platinum (Pt).

5. Recovery of the material for an organic electroluminescent device according to any one of items 1 to 4, wherein the mixture contains at least one of an anthracene derivative, a diarylamine derivative, a pyrene derivative, and a perylene derivative. Way.

6. A step of obtaining a mixture containing a plurality of types of materials for organic electroluminescence devices, and

A step of fractionally recovering an eluate containing a material for an organic electroluminescent device from the mixture by a supercritical or subcritical chromatography method to obtain a plurality of active ingredients

A method for producing a material for an organic electroluminescent device through which the material for an organic electroluminescent device is produced.

By the means of the present invention, the material for an organic electroluminescent element can be efficiently recovered from a film forming apparatus such as a mask, and the recovered material can be applied to an organic electroluminescent element. A method for recovering a material and a method for producing a material for an organic electroluminescent device can be provided.

The mechanism for expressing the effect of the present invention or the mechanism of action is not clearly defined, but is estimated as follows.

According to the present invention, it is possible to improve the material utilization efficiency of the material for an organic electroluminescent device. Here, the material utilization efficiency will be described in detail by taking the vapor deposition film as an example.

The vapor deposition is performed by installing a vapor deposition cell containing an organic material in a vacuum chamber, placing the substrate facing each other, and heating the vapor deposition cell. The front side of the evaporation cell has the highest evaporation rate, and the evaporation rate decreases as the evaporation cell is separated from the center.

Since the uniformity of the film thickness of the deposited thin film is required, it is necessary to separate the distance between the deposition cell and the substrate. For example, in the case of depositing in a square area of 200 mm on one side, the film thickness of the peripheral part to the film thickness of the center is to be suppressed to 95%. Assuming that the emission angle dependence of the deposition is the power of (COSθ) to the power of 2.5, the distance between the deposition cell and the substrate needs to be separated by 1028 mm. At this time, the ratio of the material deposited in the square area with one side of 200 mm is 2.06%, and the rest is adhered to and deposited on a barrier plate or the like arranged to prevent adhesion to the chamber.

In addition, in order to take charge of full-color display, the organic light-emitting material is patterned on pixels of three primary colors of light (red, blue, and green) using a shadow mask. For this reason, the ratio of the organic material deposited in the display pixel area becomes 1/3 or less, and the remaining 2/3 or more materials are deposited on the shadow mask.

Therefore, the deposition rate on the light emitting pixels is less than about 1%, and the remaining about 99% is attached to the shadow mask or the anti-deposition plate.

As described above, the material utilization efficiency in vapor deposition film formation is considered to be about 1% in theory, and the improvement in material utilization efficiency has a great effect not only in reducing the material cost but also in reducing the overall cost of the organic EL device. Here, the evaporation method has been described as an example. However, even if the use efficiency is large or small, even in the coating film forming method using a mask, which is one of the coating film forming methods, increasing the material utilization efficiency has a large advantage in terms of cost.

Further, since the organic EL device material is required to have high purity, it is a material having a high refining cost and a high added value, and reuse is desired.

Particularly, the organometallic complex containing Ir or Pt used in a light emitting material or the like is expensive because of its high function, and reuse of Ir or Pt is also desired from the viewpoint of usefulness and scarcity as a metal.

When reused, in particular, organometallic complexes containing metal elements such as Ir are known to undergo decomposition or chemical changes in small amounts due to heating by the evaporation film formation process, and device performance over time in long-term evaporation film formation. It is known that this is changing.

For example, it is known that there are cases in which a ligand is substituted and a substituted positional isomer is generated when the Ir organometallic complex is maintained under a high temperature condition. In order to separate such substitutional isomers, a recovery method capable of recognizing subtle structural differences is required, but separation by liquid chromatography or gel permeation chromatography is difficult in many cases. In addition, separation itself becomes possible by combining a plurality of purification methods or performing it repeatedly, but in this case, it is disadvantageous in terms of purification cost.

In addition, when a mixture of an organic compound and an organometallic complex is to be recovered by a sublimation method, there are cases in which a film is formed on the mixture or the color of the mixture is changed, and the sublimation efficiency is lowered or the purity of the sublimated purified product is not improved. There was a task that I did not.

As described above, recovery and reuse of the material for an organic EL device is desired from the viewpoint of improving productivity, but there are technical difficulties and problems in terms of cost.

Further, according to the present invention, it is possible to improve the material utilization efficiency of the material for an organic EL device at low cost. As the reason, it will be described in detail below while comparing with other methods.

In general, it is known that the performance of an organic EL device is greatly influenced by the purity of the material. This is considered to be because the presence of impurities in the thin film affects carrier transport and generation and diffusion of excitons.

As an idea supporting this, it is possible to take LEDs, and in LEDs that use light emission from excitons generated by carrier movement, recombination and recombination, like in organic EL, improvement of material purity and purity management are important factors directly connected to performance. For this reason, the purity of the inorganic semiconductor material used in the LED is 99.9999% or more.

In the case of organic EL, the material constituting the functional layer is an organic material, and the purity of the organic material is required to be 99.5% or more, preferably 99.9% or more. In order to purify the organic material with high purity to the same degree as the inorganic semiconductor material, a great difficulty is thus practically impossible.

As a general method for purifying organic materials, methods such as recrystallization, column chromatography, gel permeation chromatography, liquid chromatography, and sublimation purification methods are known. The purification apparatus and characteristics of these methods are summarized in Table 1 below. In addition, in Table 1, evaluation of the degree of purification ◎, ○, Δ, and × indicate that the degree of purification decreases in this order. In addition, evaluation of cost (circle), (triangle|delta), and x indicate that cost increases in this order.

The recrystallization method (including the crystallization method) is a purification method using the temperature dependence of the solute solubility on the solvent or the solubility difference between a single solvent and a mixed solvent, and high purity purification is possible by single crystallizing a material. Further, the crystallization method is a method generally used to improve the purity of low-purity materials, but in order to achieve high purity, it is necessary to perform single crystallization. However, single crystallization of a material requires know-how for each material, and it is not easy to single crystallize a large number of samples at once. In addition, the single crystal often contains impurities such as solvent molecules, and when a single crystal is used as a material for an organic EL device, there is a possibility that the solvent molecules contained in the single crystal become a problem.

The column chromatography method and the liquid chromatography method have a purification mechanism using adsorption and desorption equilibrium by interaction between silica gel and modified silica gel and a solute, and are common methods for purifying purity up to 99.0% or more. However, in this method, when the adsorption power is increased to purify high purity (when the adsorption equilibrium is increased), the development time takes a long time, and the developing solution (organic solvent) must be continuously flowed for the amount of the development time, and the cost of the solvent This becomes the task.

Gel permeation chromatography has a purification mechanism using a difference in permeation rate of a gel pore size, and it is possible to recognize a difference in molecular weight or molecular size. This method is not suitable for separation and purification of a plurality of materials having similar molecular weights or near molecular sizes, as apparent from the purification apparatus, and in the case of performing high purity purification, it is used in combination with a chromatography method (column chromatography, liquid chromatography). It is normal. In addition, this method has a problem in terms of cost, such as requiring a large amount of organic solvent in the developing solution, similarly to the chromatography method.

In the sublimation purification method, the material's intrinsic sublimation temperature is used as a refining device, and in general, under high vacuum conditions, a material is installed in one side of a glass tube, and a glass tube in the portion where the material is installed is heated to sublimate the material, and It is a method of moving to and re-solidifying the material by a temperature gradient. Since this method is accompanied by transformation of the material called sublimation, it is possible to completely remove low-boiling compounds such as solvents contained in the solid before purification, and in that it is possible to remove materials that are not sublimated. This is a commonly used method. However, resolidification after sublimation depends on the temperature gradient, and the gaseous material under high vacuum must be controlled by a temperature change outside the glass tube, which is not suitable for separation and purification of materials (analogs) having an approximate sublimation temperature.

In addition, it is known that more labor is required to separate and recover a plurality of materials. As an example, the recovery of the organic electroluminescent material described above will be described as an example.

As described above, in the case of manufacturing a full-color display device by vapor deposition using a shadow mask, at least two types of a light emitting material and a host material are included in the display pixel region. In addition, in the case of vacuum-forming each of the red, blue, and green pixels using the same shadow mask, a plurality of light emitting materials and a plurality of host materials are deposited on the shadow mask. Recovering a single material from such a mixture of multiple materials is considered for each of the above-described purification methods.

When a plurality of materials are recovered by a recrystallization method, as described above, since recrystallization is a purification method utilizing the temperature dependence of a solute (material) on a solvent, it is difficult to purify a material with a small proportion. Further, in general, all materials for organic EL devices are poorly soluble in a solvent, and thus there is a problem that the difference in solubility of each material is not sufficient for separation. Of course, it is not theoretically impossible to recover each of the plurality of components by using a method such as repeating the recrystallization method, but it is clear that great labor is involved. As described above, the recrystallization method is not suitable for recovery of a plurality of materials, and is generally a purification method used when a very small amount of impurities are mixed with respect to the main component that occupies the majority.

Column chromatography, liquid chromatography, and gel permeation chromatography, as described above, are purification methods using properties of a single molecule such as the interaction between silica gel and a solute or difference in molecular size, and are suitable methods for recovering multiple materials. . However, as described above, the problem in terms of cost is large and it is not suitable for practical use.

When multiple materials are recovered by the sublimation purification method, the difference in sublimation temperature of each material is an important point, and how the temperature gradient can be controlled is an important point for recovery. However, in order to perform sublimation purification under high vacuum conditions and to make the heat distribution inside the glass tube uniform, further examination and device design are required, and control of the temperature gradient is not easy. As described above, the sublimation purification method is not suitable for the recovery of multiple materials, and, like the recrystallization method, is only used for purification of the main component that occupies the majority or removal of low-boiling compounds such as solvents.

As described above for a purification method for recovering a single material from a mixture of a plurality of materials, the recrystallization method and the sublimation purification method contain a problem in principle and are not suitable. In addition, since the chromatography method is a purification apparatus that recognizes and distinguishes each molecule, it is suitable as a method, but in actual purification, there are disadvantages such as an increase in the number of steps and an increase in cost, so it is not easy.

As described above, all of the existing purification methods have advantages and disadvantages, and it has been difficult to perform high-purity purification by a single method. In addition, in the case of attempting to perform high-purity purification as required for an organic EL material, it is necessary to use a combination of a plurality of purification methods, and there is also a problem in terms of cost.

In addition, for the purification of inorganic materials in LEDs, the John Melt method and the Czochralski method are used. These methods realize high purity by using the height of the crystallinity of the material to solidify the heated and dissolved material. Also for organic materials, large single crystals using the Czochralski method have been obtained for benzophenone with high crystallinity (J. Crystal Growth, 99, 1009 (1990)). However, as for the material for an organic EL device, forming an amorphous film as an organic layer of an organic EL device is known as an essential factor for the performance expression, and a material having low crystallinity is generally used. For the purification of a material for an organic EL device designed to increase amorphous property, it is assumed that a considerable difficulty is involved in applying the method used for purification of a highly crystalline material, and is unsuitable.

In contrast to the above-described method, the supercritical or subcritical chromatography method of the present invention has a purification mechanism using the adsorption and desorption equilibrium of a solute and silica gel or modified silica gel, similarly to the column chromatography method. Also characteristically, the developing solution is in a supercritical or subcritical state. Chromatography using a supercritical or subcritical state has superior diffusibility of the developing solution compared to liquid chromatography, so that more efficient adsorption and desorption is possible, and purification with a very high number of theoretical plates is realized. It is possible. By enabling such high purification efficiency, it is possible to efficiently separate a very small amount of impurities generated during film formation or over time and recover the active ingredient. Further, the second to achieve the critical or sub-critical state, in the case of using the CO ₂ with the modifier, the cost of development solution is dependent on the CO ₂ and the modifier, but the low CO ₂ cost point, less modifier required amount is In this regard, it is also superior in terms of refining cost. In addition, since the eluted CO ₂ is evaporated, only a small amount of modifier remains in the eluate, and it is possible to obtain a solution containing a high concentration of the recovered material, and it has the advantage that it is possible to reduce the time and cost required for solvent distillation. .

1 is a schematic diagram of an apparatus using a packed column in a supercritical fluid chromatography method.
2 is a schematic diagram showing an example of a display device made of an organic EL element.
3 is a schematic diagram of the display portion A.
4 is a schematic diagram showing a circuit of a pixel.
5 is a schematic diagram of a passive matrix type full color display device.

In the method for recovering a material for an organic electroluminescent device of the present invention, a mixture containing a plurality of types of materials for an organic electroluminescent device is recovered by a supercritical or subcritical chromatography method, and a plurality of active ingredients Get

This feature is a technical feature common to or corresponding to the invention according to the present embodiment.

As an embodiment of the present invention, it is preferable from the viewpoint of improving the recovery efficiency that the molecular weight difference between any two materials for organic electroluminescent elements contained in the mixture is 200 or more.

It is preferable that the said mixture contains at least 1 type of organic compound and at least 1 type of organometallic complex. Thereby, by recovering and reusing an expensive organometallic complex, manufacturing cost can be reduced.

It is preferable that the organometallic complex is a phosphorescent dopant containing iridium (Ir) or platinum (Pt) from the viewpoint of reducing the environmental load and reducing the manufacturing cost.

It is preferable that the mixture contains at least one of an anthracene derivative, a diarylamine derivative, a pyrene derivative, and a perylene derivative from the viewpoint of reducing manufacturing cost.

The method for producing a material for an organic electroluminescent device of the present invention includes a step of obtaining a mixture containing a plurality of types of materials for an organic electroluminescent device, and from the mixture by a supercritical or subcritical chromatography method. An organic electroluminescent device material is prepared through a step of fractionally recovering the eluate containing the organic electroluminescent device material to obtain a plurality of active ingredients.

Thereby, it is possible to efficiently recover the material for an organic electroluminescent device from a film forming device such as a mask, and the recovered material can be used to prepare a material for an organic electroluminescent device applicable to the organic electroluminescent device. Can provide.

Hereinafter, the present invention, its constituent elements, and forms and aspects for carrying out the present invention will be described in detail. In addition, in this application, "to" is used by the meaning including the numerical value described before and behind it as a lower limit and an upper limit. In addition, in the present invention, ratios such as "%" and "ppm" are based on mass.

[Summary of the method of recovering the material for an organic electroluminescent device of the present invention]

In the method for recovering a material for an organic EL device of the present invention, a mixture containing a plurality of types of materials for an organic electroluminescent device is recovered by a supercritical or subcritical chromatography method to obtain a plurality of active ingredients.

<mixture>

The mixture according to the present invention contains a plurality of types of materials for organic EL devices.

As such a mixture, for example, a mixture attached to the inside of the film forming apparatus of an organic EL element can be used, and as a recovery method of the mixture, for example, a method of dissolving in a solvent with high solubility, a method of supercritical washing, a method of sublimation separation. A method, a method of separating a mask or the like by attaching a sheet-shaped mask to the member, or a method of exfoliating by irradiating a laser light, and the like are mentioned.

As a method of dissolving in a solvent with high solubility, a known method such as a method of immersing a vapor deposition mask in an organic solvent such as acetone or chlorobenzene, or a method of spraying and recovering the organic solvent to the mask can be used.

In addition, as a method of supercritical cleaning, there is a method of recovering the organic EL material of the metal mask by dissolving it by contacting a subcritical or supercritical fluid with a metal mask to which an organic EL material, which is an organic substance, is attached. In addition, there is a method of putting a metal mask into a subcritical fluid processing chamber with a subcritical or supercritical fluid, cleaning the metal mask in the processing chamber, and spraying the subcritical or supercritical fluid directly onto the metal mask. Subcritical or supercritical fluids based on CO ₂ can be treated at a relatively low temperature of 60°C or less (preferably 40°C or less), and thermal deformation of the metal mask itself can be prevented, and in a stable state. In this case, there is an advantage that the metal mask itself with high precision can be reused. In addition, since the recovered subcritical or supercritical fluid is _{changed into a solution while CO 2} is evaporated by adjusting the pressure and temperature, a solution containing a high concentration of an organic EL material or a solution in which the organic EL material is solidified and dispersed is used. It also has the advantage that it becomes possible to obtain. In the present invention, it is preferable to recover the mixture by supercritical cleaning using a subcritical or supercritical fluid.

As a method of separating the mask by attaching a sheet-shaped mask to a member, a method of forming a protective layer mainly composed of a polymer resin on one side or both sides of the mask is known. That is, a metal mask/protective layer or a protective layer/metal mask/protective layer is a basic configuration.

With such a configuration, when a protective layer mainly composed of a polymer resin is used in close contact with the substrate for pattern formation during pattern formation, not only the organic EL element material is deposited on the protective layer, but also the pattern is formed. It is possible to reduce scratches on the substrate. By reducing the number of scratches on the substrate for pattern formation, the problem of foreign materialization due to peeling of the film is eliminated, and it is possible to reuse the pattern repeatedly as it is or simply by performing simple washing without washing the mask for forming the pattern, and it is made of metal. It becomes possible to substantially avoid the problem that the manufacturing cost of the pattern forming mask is high.

The material for an organic EL device contained in the mixture refers to a compound that can be used for an organic functional layer (also referred to as "organic EL layer" and "organic compound layer") formed between an anode and a cathode to be described later.

As a compound that can be used as a material for an organic EL device, it is a known compound generally used for organic functional layers such as a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer and an electron transport layer.

(1) Compounds used in the light-emitting layer

There is no restriction|limiting in particular about the compound used for a light emitting layer, What is known as a light emitting material in a conventional organic EL element can be used. These light-emitting materials are mainly organic compounds, and depending on the desired color tone, for example Macromol. Symp. 125, the compound described in pages 17 to 26 may be mentioned. Further, the light-emitting material may be a polymer material such as p-polyphenylene vinylene or polyfluorene, and a polymer material in which the light-emitting material is introduced into the side chain, or a polymer material in which the light-emitting material is the main chain of the polymer may be used. . Further, as described above, since the light emitting material may have a hole injection function and an electron injection function in addition to the light emission performance, most of the hole injection material or electron injection material described later can be used as the light emitting material.

In the layer constituting the organic EL device, when the layer is composed of two or more types of organic compounds, the main component is referred to as a host, and other components are referred to as a dopant, and when a host and a dopant are used in combination in the light emitting layer, the main component is the host compound. The mixing ratio of the dopant (hereinafter also referred to as the light-emitting dopant) of the light-emitting layer to the light-emitting layer is preferably 0.1 to less than 30% by mass by mass.

The dopants used in the light emitting layer are broadly divided into two types: a fluorescent dopant that emits fluorescence and a phosphorescent dopant that emits phosphorescence.

Representative examples of fluorescent dopants include, for example, anthracene derivatives, diarylamine derivatives, pyrene derivatives, perylene derivatives, coumarin pigments, pyran pigments, cyanine pigments, chromonium pigments, squarylium pigments, oxobenzanthracene pigments A dye, a fluorescein dye, a rhodamine dye, a pyryllium dye, a stilbene dye, a polythiophene dye, a rare earth complex fluorescent substance, and other known fluorescent compounds.

As the material used for the light emitting layer in the present invention, it is preferable to contain a phosphorescent compound.

The phosphorescent compound is a compound in which light emission from a triplet is observed, and a phosphorescent quantum yield is 0.001 or more at 25°C. Phosphorescence quantum yield is preferably 0.01 or more, more preferably 0.1 or more. The phosphorescence quantum yield can be measured by the method described on page 398 (Maruzen, 1992 edition) of Spectroscopy II of the fourth edition experimental chemistry lecture 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescent compound used in the present invention may achieve the phosphorescence quantum yield in any of any solvents.

The phosphorescent dopant is a phosphorescent compound, and a representative example thereof is preferably a complex system compound containing a metal of Group 8 to 10 in the periodic table of the elements, more preferably an iridium compound, an osmium compound, a rhodium compound, a palladium compound, or It is a platinum compound (platinum complex system compound), and among these, an iridium compound, a rhodium compound, and a platinum compound are preferable, and an iridium compound is most preferable.

Examples of dopants are compounds described in the following documents or patent publications. J. Am. Chem. Soc. Volume 123, pages 4304 to 4312, WO00/70655, 01/93642, 02/02714, 02/15645, 02/44189, 02/081488, Japanese Patent Laid-Open Publication No. 2002-280178, 2001-181616 2002-280179, 2001-181617, 2002-280180, 2001-247859, 2002-299060, 2001-313178, 2002-302671 Publications, 2001-345183, 2002-324679, 2002-332291, 2002-50484, 2002-332292, 2002-83684, Japanese Patent Publication No. 2002- 540572, Japanese Patent Publication No. 2002-117978, 2002-338588, 2002-170684, 2002-352960, 2002-50483, 2002-100476, 2002-173674, 2002-359082, 2002-175884, 2002-363552, 2002-184582, 2003-7469, Japanese Patent Publication No. 2002-525808 , Japanese Patent Publication No. 2003-7471, Japanese Patent Publication No. 2002-525833, Japanese Patent Publication No. 2003-31366, 2002-226495, 2002-234894, 2002-235076 Publications, 2002-241751, 2001-319779, 2001-319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572 , 2002-203678, etc.

Specific examples of the phosphorescent dopant will be given below, but the present invention is not limited thereto.

Examples of the host compound include those having a basic skeleton such as a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, and an oligoarylene compound, as described below. Examples of suitable electron transport materials and hole transport materials are also mentioned. When applied to a blue or white light emitting device, a display device, and a lighting device, the maximum fluorescence wavelength of the host compound is preferably 415 nm or less, and when a phosphorescent dopant is used, the 0-0 band of phosphorescence of the host compound is 450 nm. It is more preferable to be below. As the light-emitting host, a compound having a hole-transporting ability and an electron-transporting ability, further preventing a longer wavelength of light emission, and having a high Tg (glass transition temperature) is preferable.

As a specific example of a light emitting host, a compound described in the following documents is suitable, for example.

Japanese Patent Application Laid-Open No. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860 Publications, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579 , 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002 2002-302516, 2002-305083, 2002-305084, 2002-308837, etc.

(2) Compounds used in the hole injection layer and the hole transport layer

The compound (hole injection material) used for the hole injection layer has either hole injection or electron barrier properties. Further, the compound (hole transport material) used for the hole transport layer has an electron barrier property and an action of transporting holes to the light emitting layer. Therefore, in the present invention, the hole transport layer is included in the hole injection layer. These hole injection materials and hole transport materials may be either organic or inorganic.

Specifically, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino substituted chalcone derivatives, oxazole derivatives , Styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, porphyrin compounds, and conductive polymer oligomers such as thiophene oligomers. Among these, an arylamine derivative and a porphyrin compound are preferable. Among the arylamine derivatives, aromatic tertiary amine compounds and styrylamine compounds are preferred, and aromatic tertiary amine compounds are more preferred.

Representative examples of the aromatic tertiary amine compound and styrylamine compound include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl; N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD); 2,2-bis(4-di-p-tolylaminophenyl)propane; 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane; N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl; 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane; Bis(4-dimethylamino-2-methylphenyl)phenylmethane; Bis(4-di-p-tolylaminophenyl)phenylmethane; N,N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl; N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis(diphenylamino)biphenyl; N,N,N-tri(p-tolyl)amine; 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)styryl] stilbene; 4-N,N-diphenylamino-(2-diphenylvinyl)benzene; 3-methoxy-4'-N,N-diphenylaminostilbene; N-phenylcarbazole, furthermore having two condensed aromatic rings described in the specification of U.S. Patent No. 5061569 in a molecule, for example 4,4'-bis[N-(1-naphthyl)-N-phenyl Amino] biphenyl (hereinafter abbreviated as α-NPD), triphenylamine units described in Japanese Patent Laid-Open No. Hei 4-308688 4,4',4"-tris [ N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA), etc. In addition, inorganic compounds such as p-Si and p-SiC can also be used as the hole injection material.

In addition, it is preferable that the hole transport material of the hole transport layer has a maximum fluorescence wavelength of 415 nm or less. That is, the hole-transporting material is preferably a compound having a hole-transporting ability, preventing a longer wavelength of light emission, and having a high Tg.

(3) Compound used for electron injection layer and electron transport layer

The electron injection layer should just have a function of transferring electrons injected from the cathode to the light emitting layer, and as the material, any one of conventionally known compounds can be selected and used. Examples of the compound (electron injection material) used in the electron injection layer include heterocyclic tetracarboxylic anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, naphthaleneperylene, and carbodiimide. , Fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like.

In addition, a series of electron-transmitting compounds described in Japanese Patent Application Laid-Open No. 59-194393 are disclosed as materials for forming a light-emitting layer in the publication, but as a result of investigation by the present inventors, they can be used as electron injection materials. I could see that. Further, in the oxadiazole derivative, a thiadiazole derivative in which an 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 injection material.

In addition, metal complexes of 8-quinolinol derivatives, such as tris(8-quinolinol)aluminum ( _{abbreviated as Alq 3} ), 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-quinol) Nolinol) zinc (Znq) or the like, and a metal complex in which the central metal of these metal complexes is substituted with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as the electron injection material.

In addition, metal free or metal phthalocyanine, or those in which the terminal thereof is substituted with an alkyl group or a sulfonic acid group, etc. can be preferably used as the electron injection material. Further, like the hole injection layer, inorganic semiconductors such as n-Si and n-SiC can also be used as the electron injection material.

It is preferable that the preferable compound used for the electron transport layer has a fluorescence maximum wavelength of 415 nm or less. That is, the compound used for the electron transport layer is preferably a compound having an electron transporting ability, preventing a longer wavelength of light emission, and having a high Tg.

Among the above-described materials for organic EL devices contained in the mixture according to the present invention, it is preferable that the molecular weight difference between any two types of materials for organic EL devices is 200 or more from the viewpoint of improving the recovery efficiency. More preferably, the molecular weight difference is preferably 5000 or less, still more preferably in the range of 200 to 2000, and particularly preferably in the range of 300 to 1000.

Further, it is preferable that the mixture according to the present invention contains at least one kind of organic compound and at least one kind of organometallic complex. In general, since organometallic complexes are expensive, manufacturing costs can be significantly reduced by recovering and using them.

Examples of the organometallic complex include the above-described phosphorescent dopant, and a phosphorescent dopant containing Ir or Pt is preferable in terms of reducing manufacturing cost. Specifically, it is preferable that it is an organometallic complex having Ir from the viewpoint of reducing the environmental load and reducing the manufacturing cost.

In addition, the mixture preferably contains at least one of an anthracene derivative, a diarylamine derivative, a pyrene derivative, and a perylene derivative, preferably any of an anthracene derivative and a diarylamine derivative, and an anthracene derivative. It is more preferable.

Preferred anthracene derivatives, diarylamine derivatives, pyrene derivatives and perylene derivatives include, but are not limited to, those shown below.

<Active ingredient>

The plurality of active ingredients obtained by recovering from the mixture by a supercritical or subcritical chromatography method by the method for recovering the material for an organic EL device of the present invention means a component effective as a material for an organic EL device, A very small amount of impurities generated in the film forming process of the organic EL device does not correspond to this.

In addition, the active ingredient is preferably an organic material or a metal complex material, and the plurality of active ingredients may be a plurality of organic materials or a plurality of metal complex materials, and the organic material and the metal complex material are each single or Any of the materials contained in plural may be used. Particularly preferably, both an organic material and a metal complex material are contained.

In addition, for the active ingredient to be contained, the recovery from the shadow mask by the vapor deposition method is considered as an example. When a plurality of layers are formed using the same shadow mask, the material of each layer is also deposited on the shadow mask. In addition, when a different shadow mask is used in each of the layers, when the material constituting each layer is independent, a single material is deposited. Considering the area to form a pixel, in the case of forming a single color pixel, at least two types of a light emitting dopant and a host are deposited, so that a case in which a plurality of light emitting dopants is used to obtain a desired color, and a plurality of light emitting dopants are used to adjust the performance. There is also a case of using a host of. Further, in the case of obtaining white light emission, a layer needs to be formed by at least two types of light-emitting dopants and a host. In this way, when forming a pixel layer, a plurality of materials are mixed, and in recent years, a functional layer, which has been formed with only a single material, is also formed by mixing or laminating a plurality of materials with the intention of enhancing the functionality of the device. There are many cases to be made. As described above, in particular, in recent years, there is an increasing expectation as a method of recovering a single material from a mixture of multiple materials.

When there is only one active ingredient, e.g., when the functional layer is vapor-deposited with only a single material, and only a single material is formed on the shadow mask, a collection review has already been conducted using various purification methods, and some of them are reused. Has become. However, in recent years, the number of functional layers formed of a single material or formed using a single shadow mask has decreased, and expectations for a purification method for recovering each single material from a mixture containing a plurality of active ingredients are expected. It is improving. However, there is no technically established method for the recovery method yet, and the sublimation purification method used for recovering a single material is, as described above, in principle inadequate from the viewpoint of the purification mechanism.

As the plurality of active ingredients in the present invention, a light emitting layer in an organic EL device, i.e., at least two active ingredients of a light emitting dopant and a host material, can be exemplified as suitable examples. Even if a functional layer other than the light emitting layer is used, a plurality of materials It goes without saying that in addition to regions contributing to light emission, such as a case that is used by being mixed or stacked, or on a shadow mask, deposited materials may also be mentioned.

Phosphorescent dopants may contain rare metals such as Ir, Pt, and the like, and are generally expensive and require high recovery. However, in general, since the phosphorescent dopant is a metal complex, it is poorly soluble compared to the host, and it is difficult to purify by a recrystallization method. In addition, since the molecular weight is larger than that of the host, when separating by the sublimation purification method is attempted, the dopant is deposited on the upper part of the host material, and the separation and recovery are not easy.

Fluorescent dopants are generally formed only from organic substances, and are often similar in molecular structure, molecular weight, and solubility to host materials. For this reason, not only is it difficult to separate by recrystallization, but also purification by sublimation purification is not easy. In addition, since chromatographic methods, which are generally effective means for separating a plurality of components, have similar molecular structures and molecular weights, a great effort is required for the separation, for example, a conditional examination is required.

Since the luminescent dopant has high functionality, there are cases where it is traded at a price several times higher than that of other electron transport materials or hole transport materials, and in some cases, 10 times or more. Separation and recovery of contained active ingredients is particularly effective for reducing device manufacturing costs.

A plurality of active ingredients in the present invention refers to a plurality of ingredients as a material for an organic EL device, and at this time, one active ingredient may contain an isomer. In addition, there are two classifications of isomers, structural isomers and stereoisomers, but isomers in the present invention are defined as stereoisomers. Further, in the present invention, it is preferable to contain isomers such as rotational isomers, optical isomers, and atropisomers.

In addition, as disclosed in Japanese Laid-Open Patent Application Laid-Open No. 7-89950, it is generally known to separate isomers such as optical isomers in purification. The isomers may have different effects on the living body, and there are cases that require separation and purification, but there is no need for separation and purification for the active ingredient in the present invention. This is because the isomer in the present invention has an approximate property value. It is preferable that the material having an isomer does not remove the isomer and obtains a mixture containing the isomer as an active ingredient.

<Supercritical or subcritical chromatography method>

The chromatography method is a method of using fine particle silica gel in a stationary phase, adsorbing compound (A) thereto, and gradually eluting it in a mobile phase (B) called an eluent.

At this time, with respect to the interaction (adsorption) between the silica gel surface and the compound (A), when the interaction between the compound (A) and the mobile phase (B) is antagonistic, the compound (A) is adsorbed between the silica and the mobile phase (B). -Desorption equilibrium is repeated, and when the interaction with silica is small, it elutes quickly, and when the interaction is large, it elutes late.

At this time, since the number of theoretical stages (that is, purification efficiency) increases as the number of reciprocations of the adsorption-desorption equilibrium increases, the purification efficiency by chromatography is proportional to the length of the stationary bed, and is proportional to the passage speed of the mobile bed. It is also proportional to the surface area of.

In the present invention, a supercritical or subcritical chromatography method is used among the chromatography methods. The supercritical or subcritical chromatography method, which will be described later, is preferable in that it can realize a high number of theoretical stages and does not have a problem of concentrating a large excess of poor solvent.

A means for solving the problem of concentration of poor solvent is a supercritical or subcritical chromatography method, and a chromatography method using a supercritical or subcritical fluid (supercritical or subcritical carbon dioxide).

Supercritical carbon dioxide is made of carbon dioxide as a supercritical fluid at high temperature and high pressure, and it is possible to use other substances as such a supercritical fluid, but in that it can achieve a supercritical state at relatively low pressure and temperature, it can be used in chromatography or extraction. Only carbon dioxide is being used.

This supercritical carbon dioxide has characteristics different from ordinary fluids and liquids. It is possible to change the polarity continuously, according to the polarity of the thing to be dissolved, by changing the temperature and pressure.

For example, this supercritical carbon dioxide is used when selective extraction of docosahexaenoic acid contained in the head of a fish, and even in cleaning special clothing using adhesives, it is a supercritical solution that dissolves sebum and does not dissolve adhesives. This is accomplished by making critical carbon dioxide by controlling temperature and pressure.

Although supercritical carbon dioxide can have various polarities as described above, the polarity of supercritical carbon dioxide formed in a region of relatively low temperature and pressure is about cyclohexane or heptane. In the currently commercially available supercritical chromatography apparatus, supercritical carbon dioxide of this degree of polarity is produced in the apparatus, and it is mixed with a good solvent to enter the column, and the compound is purified by the same apparatus as conventional HPLC. .

In a chromatography system using supercritical carbon dioxide, a fluid enters a detector after passing through a column, but usually a high temperature and high pressure state is maintained until that stage, and carbon dioxide also exists as a supercritical fluid. Thereafter, carbon dioxide becomes a gas during fractionation at room temperature and pressure, and during fractionation, the carbon dioxide escapes from the solution by itself, so that concentration of the poor solvent becomes unnecessary. At this time, it is possible to recover carbon dioxide by a carbon dioxide recovery device equipped with a gas-liquid separation mechanism described in the reference literature (Journal of Biological Engineering, Vol. 88, No. 10, pages 525 to 528, 2010), and again used as a supercritical fluid. It is also possible.

In addition, since the supercritical or subcritical chromatography method is a purification method having a very high number of theoretical plates compared to the liquid chromatography method, it has an advantage that it is possible to remove a very small amount of impurities.

In addition, in general, since supercritical or subcritical chromatography is a process that uses carbon dioxide as a component of the mobile phase, compared to liquid chromatography, it is possible to reduce the amount of solvent required for recovery, and in terms of cost. Has the advantage of.

In addition, even when the solvent is removed from the recovered eluent, the eluate of the supercritical or subcritical chromatography method contains carbon dioxide gas, and the carbon dioxide gas is evaporated and opened to the atmosphere after elution. It is less compared to the liquid chromatography method. In other words, the solute concentration of the eluate of the supercritical or subcritical chromatography method is higher than that of the liquid chromatography method. When removing only the solute from the solution after chromatography recovery, it is necessary to distill the solvent to dryness, but in the supercritical or subcritical chromatography method, it is possible to reduce the energy and time required for distillation of the solvent. Also, the advantage is great.

A supercritical or subcritical chromatography method having the above advantages will be described in detail below.

For the supercritical or subcritical chromatography method, a packed column, an open column, or a capillary column can be used.

(Column for chromatography)

The column is not particularly limited as long as it has a separating agent capable of separating the target substance from the sample injected into the mobile phase.

The separating agent is selected from among various separating agents depending on the target material. The form of the separating agent is not particularly limited. For example, the column may be filled in a column while being supported on a particulate carrier, or may be accommodated in the column while being supported on an integral carrier accommodated in the column. It may be accommodated in.

In the method using a packed column, as shown in Fig. 1, a supercritical fluid 11 containing an organic solvent (including carbon dioxide), a pump 12, a modifier 13, and an organic compound to be separated if necessary. It is possible to use a device comprising an injector 14 for injecting, and a column 15 for separation, as well as a detector 17, if necessary, and a pressure regulating valve 18. The column 15 is temperature-controlled in the column oven 16. As a filler, silica used in a conventional chromatography method or a surface-modified silica can be appropriately selected.

In the present invention, the supercritical fluid refers to a substance in a supercritical state.

Here, the supercritical state will be described. The substance changes between the three states of gas, liquid, and solid according to changes in environmental conditions such as temperature and pressure (or volume), but this is determined by the balance of intermolecular force and kinetic energy. The state diagram (phase diagram) shows the change of the three states of gas, liquid, and solid by taking temperature on the horizontal axis and pressure on the vertical axis. Among them, the point in which the three phases of gas, liquid, and solid coexist and are in equilibrium. It is called a triple point. When the temperature is higher than the triple point, the liquid and its vapor are in equilibrium. The pressure at this time is the saturated vapor pressure, and is expressed as an evaporation curve (vapor pressure line). If the pressure is lower than the pressure indicated by this curve, all of the liquid is vaporized, and if a pressure higher than this is applied, all of the vapor is liquefied. Even if the pressure is kept constant and the temperature is changed, if this curve is exceeded, the liquid becomes vapor and the vapor becomes liquid. This evaporation curve has an end point on the high temperature and high pressure side, and this is called a critical point. The critical point is an important point that characterizes a substance, and in a state where the liquid and vapor cannot be distinguished, the interface of the gas-liquid is also lost.

In a state of higher temperature than the critical point, a gas-liquid coexistence state may not occur, and the liquid and gas may be changed.

A fluid above the critical temperature and above the critical pressure is referred to as a supercritical fluid, and the temperature/pressure region to which the supercritical fluid is applied is referred to as a supercritical region. In addition, a state in which any of a critical temperature or higher or a critical pressure or higher is satisfied is referred to as a subcritical (expanded liquid) state, and a fluid in a subcritical state is referred to as a subcritical fluid. Supercritical fluids and subcritical fluids can be understood as high-density fluids with high kinetic energy, and exhibit liquid behavior in terms of dissolving solutes and gaseous characteristics in terms of density variability. Although the supercritical fluid has various solvent properties, it is an important property that it has low viscosity, high diffusion, and excellent permeability into solid materials.

The supercritical state is, for example, carbon dioxide, the critical temperature (hereinafter, also referred to as Tc) 31°C, the critical pressure (hereinafter, also referred to as Pc) is 7.38×10 ⁶ Pa, propane (Tc=96.7°C, Pc=43.4× 10 ⁵ Pa), ethylene (Tc = 9.9 °C, Pc = 52.2 × 10 ⁵ Pa), etc., if the fluid is above this range, the fluid has a large diffusion coefficient and low viscosity, so that mass transfer and concentration equilibrium are quickly reached. As such, since the density is high, separation with good efficiency becomes possible. In addition, by using a substance that becomes a gas at normal pressure and room temperature, such as carbon dioxide, recovery is quick. In addition, there are no various obstacles due to the inevitable residual of a trace amount of solvent in the purification method using a liquid solvent.

As a solvent used as a supercritical fluid or a subcritical fluid, carbon dioxide, dinitrogen monoxide, ammonia, water, methanol, ethanol, 2-propanol, ethane, propane, butane, hexane, pentane, etc. are preferably used. It can be used preferably.

One type of solvent used as a supercritical fluid or a subcritical fluid can be used alone, or a so-called modifier (entrainer) can be added to adjust the polarity.

Examples of modifiers include hydrocarbon-based solvents such as hexane, cyclohexane, benzene, and toluene, halogenated hydrocarbon-based solvents such as methyl chloride, dichloromethane, dichloroethane, and chlorobenzene, and alcohol-based solvents such as methanol, ethanol, propanol, and butanol. , Ether solvents such as diethyl ether, tetrahydrofuran (THF), acetal solvents such as acetaldehyde diethyl acetal, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and butyl acetate, Carboxylic acid solvents such as formic acid, acetic acid and trifluoroacetic acid, nitrogen compound solvents such as acetonitrile, pyridine, and N,N-dimethylformamide, sulfur compound solvents such as carbon disulfide and dimethyl sulfoxide, and water, Nitric acid and sulfuric acid.

The use temperature of the supercritical fluid or the subcritical fluid is basically not particularly limited as long as it is above the temperature at which the mixture containing the material for an organic EL device according to the present invention is dissolved, but if the temperature is too low, the mixture In some cases, the solubility in the supercritical fluid or subcritical fluid may be insufficient, and if the temperature is too high, the material for the organic EL device may be decomposed. Therefore, the operating temperature range should be within the range of 20 to 600°C. desirable.

The working pressure of the supercritical fluid or the subcritical fluid is not particularly limited as long as it is basically higher than the critical pressure of the substance used, but if the pressure is too low, the solubility of the mixture in the supercritical fluid or subcritical fluid may be insufficient. In addition, if the pressure is too high, problems may arise in terms of durability of the manufacturing apparatus, safety during operation, and the like, so that the working pressure is preferably in the range of 1 to 100 MPa.

A device using a supercritical fluid or a subcritical fluid is not limited at all as long as the mixture has a function of dissolving in the supercritical fluid or subcritical fluid by contacting the supercritical fluid or the subcritical fluid. A batch method in which a critical fluid or a subcritical fluid is used as a closed system, a distribution method in which a supercritical fluid or subcritical fluid is circulated, and a complex method in which a batch method and a distribution method are combined can be used.

In the supercritical or subcritical chromatography method according to the present invention, after injecting a sample into the mobile phase, the composition of the mobile phase is changed, and the tailing of the peak of the target substance with the slowest elution from the column is all attenuated. It is preferable to perform sample injection.

The step of changing the composition of the mobile phase is to change the composition of a supercritical fluid or a mobile phase containing a subcritical fluid and a solvent. By changing the composition of the mobile phase by this process, the attenuation of the tailing of the peak can be accelerated. In column adsorption supercritical fluid or subcritical fluid chromatography, particularly when performing a preparative operation in which a relatively large amount of the compound to be separated is loaded, the peaks show remarkable tailing. If the next sample is injected before the tailing is attenuated, the tailed component is mixed into the peak component of the next injected sample, resulting in a decrease in the purity of the separated compound, resulting in a problem. Therefore, after waiting for the complete decay of the tailing, it is necessary to inject the next sample. Accordingly, the timing of the next sample injection can be accelerated by increasing the attenuation of the tailing, but by changing the composition of the mobile phase, the extrusion of the peak component from the column can be accelerated, and the attenuation of the tailing can be accelerated.

Changing the composition in the mobile phase produces an effect similar to the step gradient method referred to in liquid chromatography, and accelerates the attenuation of tailing by promoting the extrusion of the peak component from the column.

In the supercritical fluid or subcritical fluid chromatography, since a supercritical fluid or subcritical fluid of high diffusivity and low viscosity is used, the flow rate of the mobile phase is large and the diffusivity is high, so that the column is equilibrated quickly. Therefore, even if the composition in the mobile phase changes temporarily, the column is quickly restored to the environment before the change if the composition in the mobile phase is returned to its original state, and the next sample can be injected immediately after the tailing is attenuated. As a result, the throughput per hour of the sample can be increased, and efficiency and productivity are improved.

The step of changing the composition of the mobile phase according to the present invention may be performed by any method as long as it can be performed in a supercritical or subcritical chromatography apparatus. For example, by increasing the solvent ratio in the mobile phase, a change in the composition of the mobile phase can occur, and even by changing the pressure or column temperature, the CO ₂ density in the mobile phase changes, including these, as a composition change of the mobile phase. .

A solvent is already contained in the mobile phase, but apart from the solvent contained in the mobile phase, a solvent injection device is provided upstream of the column and downstream of the mobile phase generating device, so that the ratio of the solvent in the mobile phase can be increased. The solvent injection device can be, for example, a solvent injection device composed of a loop pipe for holding a solvent to be injected, a flow path switching valve, and a solvent injection pump.

The loop pipe used for the solvent injection device is a pipe having a predetermined volume. Having a loop piping is preferable because the quantification of the injection of the sample is improved, and it is possible to inject a larger amount of the sample. In the present invention, the volume of the loop pipe differs depending on conditions such as the type of column used in the supercritical fluid or subcritical fluid chromatography apparatus, the inner diameter of the column, the type of target material, and the composition of the mobile phase. Since it is necessary to inject a large amount of solvent at one time, it is preferable that the loop pipe of the solvent injection device is larger than the loop pipe of the sample injection device and can hold a large amount of solvent.

The flow path switching valve used in the solvent injection device is not particularly limited as long as it is a valve or cock that can be opened or closed provided in the flow path of the mobile phase. For example, a valve used in combination with a two-way valve and a butterfly valve, or a three-way valve to switch the flow path of the mobile phase is exemplified. The solvent injection pump used for the solvent injection device may be a high pressure pump used for sample injection in a supercritical or subcritical chromatography device.

When a solvent injection device is used, the injection of the solvent is performed by switching the flow path switching valve and sending the solvent to the moving phase of the column by the solvent injection pump. In the injection of the solvent, it is preferable to inject a solvent equal to or greater than the injection volume of the sample, preferably equal to or greater than 2 times, and more preferably equal to or greater than 5 times in an instant. As the upper limit, it is preferable to inject a solvent of 30 times or less, preferably 20 times or less, more preferably 15 times or less of the injection volume of the sample. By setting it as such a solvent injection amount, the attenuation of the tailing of the peak becomes faster.

The solvent injected from the solvent injection device is not particularly limited, and may be, for example, the same solvent as the solvent contained in the mobile phase, or may be a different solvent. In addition, the number of solvents to be injected may be one or two or more.

In particular, a solvent having a high polarity is preferable in that the attenuation of the tailing is accelerated. In addition, it is preferable to use a solvent having a higher polarity compared to the solvent contained in the mobile phase.

Both the steps of changing the composition of the mobile phase and the step of returning the composition of the mobile phase to before the change are preferably performed in an instant. The instantaneous term as used herein may be a sufficient time to cause a change in the mobile phase. Both processes are performed within 30 seconds, preferably within 10 seconds, in that the timing of the next sample injection is also accelerated by rapidly equilibrating the mobile phase.

The method of detecting the peak is not particularly limited, but in general, the timing can be determined by the peak detected by a detector of a supercritical fluid or subcritical fluid chromatography, for example, an ultraviolet absorption spectrometer.

[Method of manufacturing organic electroluminescent device material]

The method of manufacturing the material for an organic EL device of the present invention includes a step of obtaining a mixture containing a plurality of types of materials for an organic electroluminescence device, and an organic electroluminescence by supercritical or subcritical chromatography method from the mixture. An organic electroluminescent device material is prepared through a step of fractionally recovering the eluate containing the material for a nessense element to obtain a plurality of active ingredients.

In the method for producing the material for an organic EL device of the present invention, the mixture, supercritical or subcritical chromatography, and the active ingredient are the mixture in the method for recovering the material for an organic EL device of the present invention described above, supercritical Or it has the same meaning as a subcritical chromatography method and an active ingredient.

The material for an organic EL device manufactured by the method for producing the material for an organic EL device of the present invention includes a compound similar to the material for an organic EL device contained in the mixture. That is, it is a known compound generally used for organic functional layers such as a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer and an electron transport layer.

[Organic Electroluminescence Device]

An organic EL device obtained by using the material for an organic EL device manufactured by the method for producing the material for an organic EL device of the present invention will be described.

The organic EL device has an anode, a cathode, and one or more organic functional layers (also referred to as “organic EL layer” and “organic compound layer”) sandwiched between these electrodes on a substrate.

(Board)

The substrate that can be used for the organic EL device according to the present invention (hereinafter, also referred to as a substrate, a support substrate, a substrate, a support, etc.) is not particularly limited, and a glass substrate, a plastic substrate, etc. can be used, and either transparent or opaque. You can do it. In the case of extracting light from the substrate side, it is preferable that the substrate is transparent. Glass, quartz, and transparent plastic substrates are mentioned as a transparent substrate preferably used.

In addition, as a substrate, in a test conforming to JIS Z-0208, in order to prevent intrusion of oxygen or water from the substrate side, the thickness is 1 μm or more, and the water vapor transmittance is 1 g/(m ² ·24 h·atm) ( 25°C) or less.

Specifically as a glass substrate, an alkali-free glass, a low alkali glass, a soda lime glass, etc. are mentioned, for example. An alkali-free glass is preferable from the viewpoint of little adsorption of moisture, but any of these may be used as long as it is sufficiently dried.

Plastic substrates have been attracting attention in recent years because of their high flexibility, light weight, and fragility, and that they can further reduce the thickness of an organic EL device.

The resin film used as the substrate of the plastic substrate is not particularly limited, and for example, polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose tree Cellulose esters such as acetate (TAC), cellulose acetate butyrate, cellulose acetate propionate (CAP), cellulose acetate phthalate, and cellulose nitrate, or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic Polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyether sulfone (PES), polyphenylene sulfide, polysulfone, polyetherimide, polyether ketoneimide, poly Amides, fluororesins, nylons, polymethyl methacrylates, acrylics or polyarylates, organic-inorganic hybrid resins, and the like.

Examples of the organic-inorganic hybrid resin include those obtained by combining an organic resin with an inorganic polymer (eg, silica, alumina, titania, zirconia, etc.) obtained by a sol-gel reaction. Among these, a norbornene (or cycloolefin-based) resin such as Atone (manufactured by JSR Corporation) or Arpel (manufactured by Mitsui Chemical Corporation) is particularly preferable.

Plastic substrates that are usually produced have relatively high moisture permeability, and may contain moisture in the inside of the substrate. Therefore, when using such a plastic substrate, it is preferable to provide a film (hereinafter referred to as "barrier film" or "water vapor sealing film") for suppressing intrusion of water vapor or oxygen on the resin film.

The material constituting the barrier film is not particularly limited, and a film of an inorganic substance or an organic substance or a hybrid of both is used. A barrier property having a water vapor permeability (25±0.5°C, relative humidity (90±2)%RH) of 0.01 g/(m ² ·24h) or less measured by a method in accordance with JIS K 7129-1992 It is preferable that it is a film, and further, the oxygen permeability measured by the method in accordance with JIS K 7126-1987 is 10 ^-3 mL/(m ² ·24h·atm) or less, and the water vapor permeability is 10 ^-5 g/(m ² · It is preferable that it is a high-barrier film which is 24h) or less.

The material constituting the barrier film is not particularly limited as long as it has a function of suppressing the intrusion of moisture or oxygen that causes deterioration of the device. For example, inorganic substances such as metal oxides, metal oxynitrides or metal nitrides, organic substances, Alternatively, a hybrid material or the like of both can be used.

As metal oxides, metal oxynitrides or metal nitrides, silicon oxide, titanium oxide, indium oxide, tin oxide, metal oxides such as indium tin oxide (ITO), aluminum oxide, metal nitrides such as silicon nitride, silicon oxynitride, titanium oxynitride, etc. And metal oxynitrides.

In addition, in order to improve the fragility of the film, it is more preferable to have a laminated structure of a layer containing these inorganic layers and organic materials. Although there is no restriction|limiting in particular about the lamination|stacking order of an inorganic layer and an organic layer, It is preferable that both are laminated|stacked alternately multiple times.

The barrier film is a barrier film having a water vapor permeability (25±0.5°C, relative humidity (90±2)%RH) of 0.01 g/(m ² ·24h) or less measured by a method in accordance with JIS K 7129-1992. Preferably, further, the oxygen permeability measured by the method in accordance with JIS K 7126-1987 is 10 ^-3 mL/(m ² ·24h·atm) or less, and the water vapor permeability is 10 ^-5 g/(m ² ·24h) or less. It is preferable that it is a high barrier film.

The method of providing the barrier film on the resin film is not particularly limited, and any method may be used. For example, a vacuum evaporation method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, Atmospheric pressure plasma polymerization method, CVD method (chemical vapor deposition: for example, plasma CVD method, laser CVD method, thermal CVD method, etc.), coating method, sol-gel method, and the like can be used. Among these, a method by plasma CVD treatment at atmospheric pressure or near atmospheric pressure is preferable from the viewpoint of being able to form a dense film.

Examples of the opaque substrate include a metal plate such as aluminum and stainless steel, a film or an opaque resin substrate, and a ceramic substrate.

(anode)

As the anode of the organic EL element, a metal having a large work function (4 eV or more), an alloy, an electrically conductive compound of metal, or a mixture thereof is preferably used as an electrode material.

Here, the "electrically conductive compound of a metal" refers to a compound of a metal and other substances having electrical conductivity, specifically, for example, an oxide or a halide of a metal, which has electrical conductivity.

Specific examples of such electrode materials include metals such as Au, CuI, indium-tin oxide (ITO), and conductive transparent materials such as _{SnO 2 and ZnO.} The anode can be produced by forming a thin film containing these electrode materials on the substrate by a conventional method such as vapor deposition or sputtering.

In addition, a pattern of a desired shape may be formed on this thin film by a photolithography method, and when pattern precision is not very much required (about 100 μm or more), a mask of a desired shape may be used during deposition or sputtering of the electrode material. You may form a pattern through.

In the case of extracting light emission from the anode, it is preferable to increase the transmittance of more than 10%. In addition, the sheet resistance as an anode is several hundred Ω/sq. The following are preferable. In addition, although the film thickness of the anode differs depending on the material constituting it, it is usually selected in the range of 10 nm to 1 µm, and preferably 10 to 200 nm.

(Organic functional layer)

The organic functional layer (also referred to as ``organic EL layer'' or ``organic compound layer'') includes at least a light-emitting layer, but in a broad sense, the light-emitting layer refers to a layer that emits light when a current is passed through an electrode including a cathode and an anode, Specifically, it refers to a layer containing an organic compound that emits light when a current is passed through an electrode including a cathode and an anode.

The organic EL device according to the present invention may have a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer in addition to the light-emitting layer, if necessary, and take a structure in which these layers are sandwiched between a cathode and an anode.

Specifically,

(i) anode/light emitting layer/cathode

(ii) anode/hole injection layer/light emitting layer/cathode

(iii) anode/light emitting layer/electron injection layer/cathode

(iv) anode/hole injection layer/light emitting layer/electron injection layer/cathode

(v) anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode

(vi) anode/hole transport layer/light-emitting layer/electron transport layer/cathode

And the like.

In addition, a cathode buffer layer (eg, lithium fluoride, etc.) may be inserted between the electron injection layer and the cathode, and an anode buffer layer (eg, copper phthalocyanine, etc.) may be inserted between the anode and the hole injection layer. do.

(Luminescent layer)

The light-emitting layer according to the present invention is a layer that emits light by recombining electrons and holes injected from an electrode, an electron transport layer, or a hole transport layer, and a portion that emits light may be in a layer of a light-emitting layer or an interface between a light-emitting layer and an adjacent layer. The light-emitting layer may be a layer having a single composition, or may be a laminated structure including a plurality of layers having the same or different composition.

Functions, such as a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer, may be given to this light-emitting layer itself. That is, (1) when an electric field is applied to the light emitting layer, holes can be injected by the anode or the hole injection layer, and electrons can be injected from the cathode or the electron injection layer, and (2) the injected charge (electrons And holes) by the force of an electric field, and (3) a light emitting function of providing a place for recombination of electrons and holes inside the light emitting layer, and connecting them to light emission. In addition, the light-emitting layer may have a difference in the ease of injection of holes and the ease of injection of electrons, and may have a large or small transport function represented by the mobility of holes and electrons, but has a function of moving at least one of the charges. It is desirable.

The kind of light-emitting material used for this light-emitting layer is not particularly limited, and a known light-emitting material in an organic EL device can be used, and manufactured by the method for producing the material for an organic EL device of the present invention. A material for an organic EL element for a light-emitting layer can be used. As such a material for an organic EL device for a light emitting layer, it is omitted here because it has been described in the above-described recovery method of the material for an organic EL device.

In addition, as for the light-emitting dopant used in the light-emitting layer, only one of the above-described types may be used, or a plurality of types may be used, and by simultaneously extracting light emission from the plurality of types of dopants, a light-emitting element having a plurality of maximum emission wavelengths is constructed. You may. Further, for example, both a phosphorescent dopant and a fluorescent dopant may be added. When a plurality of light-emitting layers are stacked to form an organic EL device, the light-emitting dopants contained in each layer may be the same or different, or may be a single type or a plurality of types.

Further, a polymer material in which the light-emitting dopant is introduced into the polymer chain or the light-emitting dopant is the main chain of the polymer may be used.

The light-emitting dopant may be dispersed throughout the layer containing the host compound, or may be partially dispersed. A compound having another function may be added to the light-emitting layer.

(Hole injection layer and hole transport layer)

The material used for the hole injection layer and the hole transport layer is not particularly limited, and a known material may be used, and an organic EL for the hole injection layer and the hole transport layer manufactured by the method of manufacturing the material for an organic EL device of the present invention Element materials can be used. As the material for the organic EL device for the hole injection layer and the hole transport layer, it is omitted here because it has been described in the above-described recovery method for the organic EL device material.

The hole injection layer and the hole transport layer include the hole injection material and the hole transport material by known methods such as a vacuum vapor deposition method, a spin coating method, a cast method, an LB method, an inkjet method, a transfer method, and a printing method. It can be formed by making it thin.

The thickness of the hole injection layer and the hole transport layer is not particularly limited, but is usually about 5 nm to 5 µm. In addition, the hole injection layer and the hole transport layer may have a single-layer structure including one or two or more of the above materials, respectively, or a laminated structure including a plurality of layers of the same composition or different composition. In addition, in the case of providing both the hole injection layer and the hole transport layer, among the above materials, different materials are usually used, but the same material may be used.

(Electron injection layer and electron transport layer)

The material used for the electron injection layer and the electron transport layer is not particularly limited, and a known material may be used, and an organic EL for the electron injection layer and the electron transport layer manufactured by the method for producing the material for an organic EL device of the present invention Element materials can be used. As the material for the organic EL element for the electron injection layer and the electron transport layer, it is omitted here because it has been described in the above-described recovery method for the organic EL element material.

The electron injection layer can be formed by thinning the electron injection material by a known method such as a vacuum evaporation method, a spin coating method, a cast method, an LB method, an inkjet method, a transfer method, and a printing method.

In addition, the thickness as the electron injection layer is not particularly limited, but is usually selected in the range of 5 nm to 5 μm. The electron injection layer may have a single-layer structure including one type or two or more types of these electron injection materials, or may be a laminate structure including a plurality of layers of the same composition or different composition.

In addition, in the present specification, when the ionization energy of the electron injection layer is larger than that of the light emitting layer, it is specifically referred to as an electron transport layer. Therefore, in this specification, the electron transport layer is included in the electron injection layer.

The electron transport layer is also called a hole blocking layer (hole blocking layer), and examples thereof include, for example, International Publication No. 2000/70655, Japanese Patent Laid-Open No. 2001-313178, Japanese Patent Laid-Open No. 11-204258, The 11-204359 publication and "Organic EL elements and their industrialization front lines (published by N-T-S Inc. on November 30, 1998)" on page 237 and the like are mentioned. In particular, in a so-called "phosphorescent light emitting device" in which an ortho-metal complex dopant is used in the light emitting layer, it is preferable to have a configuration having an electron transport layer (hole blocking layer) as in (v) and (vi) above.

(Buffer layer)

A buffer layer (electrode interface layer) may be present between the anode and the light emitting layer or the hole injection layer, and between the cathode and the light emitting layer or the electron injection layer. The buffer layer refers to a layer provided between the electrode and the organic layer for lowering the driving voltage or improving the luminous efficiency, and the second of ``Organic EL devices and their industrialization front lines (published by NTS on November 30, 1998)''. It is described in detail in Chapter 2 "Electrode Materials" (pages 123 to 166), and includes an anode buffer layer and a cathode buffer layer.

As for the anode buffer layer, a detailed description thereof is also described in Japanese Patent Laid-Open Nos. 9-45479, 9-260062, 8-288069, etc. As a specific example, a phthalocyanine buffer layer represented by copper phthalocyanine, represented by vanadium oxide An oxide buffer layer, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

The cathode buffer layer is described in detail in Japanese Patent Laid-Open Nos. Hei 6-325871, 9-17574, 10-74586, and the like, and specifically, a metal buffer layer typified by strontium or aluminum, or lithium fluoride. Alkali metal compound buffer layer typified, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. are mentioned.

It is preferable that the buffer layer is a very thin film, and although it varies depending on the material, the thickness is preferably in the range of 0.1 to 100 nm. Further, in addition to the above-described basic constituent layers, layers having other functions may be appropriately laminated if necessary.

(cathode)

As described above, as the cathode of an organic EL device, in general, a metal having a small work function (less than 4 eV) (hereinafter referred to as an electron injecting metal), an alloy, an electrically conductive compound of metal, or a mixture thereof is used as an electrode material. Is used.

Specific examples of such electrode materials include sodium, magnesium, lithium, aluminum, indium, rare earth metal, sodium-potassium alloy, magnesium/copper mixture, magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/aluminum oxide ( Al ₂ O ₃ ) mixture, lithium/aluminum mixture, and the like.

In the present invention, the ones listed above may be used as the electrode material of the negative electrode, but from the viewpoint of more effectively exerting the effects of the present invention, the negative electrode is preferably made of a Group 13 metal element. That is, in the present invention, by oxidizing the surface of the cathode with oxygen gas in a plasma state to form an oxide film on the surface of the cathode as described later, further oxidation of the cathode can be prevented and durability of the cathode can be improved.

Therefore, the electrode material of the cathode is preferably a metal having desirable electron injection properties required for the cathode, and a metal capable of forming a dense oxide film.

As the electrode material of the negative electrode containing the Group 13 metal element, specifically, for example, aluminum, indium, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/aluminum oxide (Al ₂ O ₃ ) mixture, lithium /Aluminum mixture, etc. are mentioned. In addition, the mixing ratio of each component of the mixture may be a conventionally known ratio as the cathode of the organic EL element, but is not particularly limited thereto. The cathode can be produced by forming a thin film on the organic compound layer (organic EL layer) by a method such as vapor deposition or sputtering of the electrode material described above.

In addition, the sheet resistance as the cathode is several hundred Ω/sq. The following are preferable, and the film thickness is usually selected in the range of 10 nm to 1 µm, preferably 50 to 200 nm. In addition, in order to transmit the luminescent light, if either the anode or the cathode of the organic EL element is made transparent or semitransparent, the luminous efficiency is improved, which is preferable.

[Method of fabricating organic EL device]

As an example of a method of manufacturing an organic EL device according to the present invention, a method of manufacturing an organic EL device including an anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode will be described.

First, a thin film containing a desired electrode material, for example, a material for an anode, is formed on a suitable substrate by a method such as evaporation or sputtering to a thickness of 1 μm or less, preferably 10 to 200 nm, to prepare an anode. . Next, on this, for example, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer containing the material for an organic EL device manufactured by the method for producing an organic EL device material of the present invention. An organic compound thin film is formed.

As a method of thinning these organic compound thin films, as described above, there are spin coat method, cast method, inkjet method, vapor deposition method, printing method, etc., but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In this, a vacuum evaporation method or a spin coating method is preferable.

Further, different film forming methods may be applied for each layer. In the case of employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound to be used, but in general, boat heating temperature 50 to 450°C, vacuum degree 10 ^-6 to 10 ^-2 Pa, deposition rate 0.01 to 50 nm/sec. , It is preferable to appropriately select the substrate temperature in the range of -50 to 300°C and a thickness of 0.1 nm to 5 μm.

After forming these layers, a thin film containing a material for a cathode is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, by a method such as evaporation or sputtering, and the cathode is formed thereon. By providing, a desired organic EL element is obtained. The organic EL device is preferably fabricated from the hole injection layer to the cathode consistently in one vacuum, but may be taken out in the middle to perform a different film formation method. At this time, consideration is required, such as performing the operation in a dry inert gas atmosphere.

[Sealing of organic EL devices]

Although it does not specifically limit as a sealing means of an organic EL element, For example, after sealing the outer peripheral part of an organic EL element with a sealing adhesive, a method of arrange|positioning a sealing member so that the light emitting area of an organic EL element may be mentioned is mentioned.

Examples of the sealing adhesive include photocuring and thermosetting adhesives having reactive vinyl groups of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylic acid esters. Further, thermal and chemical curing types (two-liquid mixing), such as an epoxy type, are mentioned. Moreover, a hot melt type polyamide, polyester, and polyolefin are mentioned. Further, an ultraviolet curable epoxy resin adhesive of a cationic curing type can be mentioned.

As the sealing member, a polymer film and a metal film can be preferably used from the viewpoint of thinning the organic EL element.

In the gap between the sealing member and the light emitting region of the organic EL element, in addition to the sealing adhesive, an inert gas such as nitrogen or argon or an inert liquid such as fluorohydrocarbon or silicone oil may be injected in the gaseous and liquid form. Further, the gap between the sealing member and the display area of the organic EL element may be vacuumed, or a hygroscopic compound may be sealed in the gap.

[Display device]

In the multicolor display device using the organic EL element, a shadow mask is provided only when the light emitting layer is formed, and the other layers are common, so patterning such as a shadow mask is unnecessary, and a vapor deposition method, a cast method, a spin coat method, and an inkjet method are applied on one surface. The film can be formed by a method, a printing method, or the like.

In the case of performing patterning of only the light emitting layer, the method is not limited, but preferably a vapor deposition method, an inkjet method, or a printing method. In the case of using the evaporation method, patterning using a shadow mask is preferable.

In addition, it is also possible to manufacture in the order of a cathode, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, and an anode by reversing the manufacturing order.

When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the anode as + and the cathode as -. In addition, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. In addition, when an AC voltage is applied, light is emitted only when the positive electrode becomes + and the negative electrode becomes -. In addition, the waveform of the alternating current to be applied may be arbitrary.

The multicolor display device can be used as a display device, a display, and various light-emitting light sources. In display devices and displays, full-color display becomes possible by using three types of organic EL elements of blue, red, and green light emission.

Examples of display devices and displays include televisions, personal computers, mobile devices, AV devices, text broadcast displays, and information displays in automobiles. In particular, it may be used as a display device for reproducing a still image or a moving image, and the driving method in the case of using as a display device for reproducing a moving image may be either a simple matrix (passive matrix) system or an active matrix system.

Examples of luminescent light sources include home lighting, in-vehicle lighting, backlights for clocks and liquid crystals, sign advertisements, signal devices, light sources for optical storage media, light sources for electrophotographic copiers, light sources for optical communication processors, light sources for optical sensors, etc., but limited to this. It does not become.

Further, the organic EL device according to the present invention may be used as an organic EL device having a resonator structure.

Examples of the use of the organic EL element having such a resonator structure include, but are not limited to, a light source for an optical storage medium, a light source for an electrophotographic copying machine, a light source for an optical communication processor, and a light source for an optical sensor. Moreover, by making laser oscillation, you may use for the said use.

The organic EL device according to the present invention may be used as a type of lamp such as for lighting or an exposure light source, and as a type of projection device for projecting an image or a type of display device (display) that directly visually recognizes a still image or a moving image. You can use it. When used as a display device for moving picture reproduction, the driving system may be a simple matrix (passive matrix) system, an active matrix system, or either. Alternatively, it is possible to fabricate a full-color display device by using two or more types of the organic EL elements of the present invention having different luminous colors.

An example of a display device composed of the organic EL element according to the present invention will be described below based on the drawings.

2 is a schematic diagram showing an example of a display device made of an organic EL element. It is a schematic diagram of a display such as a mobile phone, which displays image information by light emission of an organic EL element. The display 41 includes a display unit A having a plurality of pixels, a control unit B for performing image scanning of the display unit A based on image information, and the like. The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside, and the pixels for each scanning line are converted to an image data signal by the scanning signal. In accordance with this, the light is sequentially emitted to perform image scanning, and image information is displayed on the display portion A.

3 is a schematic diagram of the display portion A. The display portion A includes a wiring portion including a plurality of scan lines 55 and data lines 56, a plurality of pixels 53, and the like on a substrate. The main members of the display portion A will be described below.

In FIG. 3, the case where light emitted from the pixel 53 is extracted in the direction of the white arrow (downward direction) is shown. The scan line 55 and the plurality of data lines 56 of the wiring unit each contain a conductive material, and the scan line 55 and the data line 56 are orthogonal to the grid shape, and are connected to the pixel 53 at orthogonal positions. (Detailed explanation is not shown). When a scanning signal is applied from the scanning line 55, the pixel 53 receives an image data signal from the data line 56 and emits light according to the received image data. Full-color display is possible by appropriately arranging pixels in a red region, a pixel in a green region, and a pixel in a blue region of the light emission color on the same substrate.

Next, the light emission process of the pixel will be described.

4 is a schematic diagram showing a circuit of a pixel. The pixel includes an organic EL element 60, a switching transistor 61, a driving transistor 62, a capacitor 63, and the like. Full-color display can be performed by using red, green, and blue light-emitting organic EL elements in a plurality of pixels as the organic EL elements 60, and placing them together on the same substrate.

In Fig. 4, an image data signal is applied from the control unit B (not shown in Fig. 4, not shown in Fig. 2) to the drain of the switching transistor 61 through the data line 56. In addition, when a scan signal is applied from the control unit B to the gate of the switching transistor 61 through the scan line 55, the driving of the switching transistor 61 is turned on, so that the image data signal applied to the drain is transferred to the capacitor 63. And are transferred to the gate of the driving transistor 62.

By transmission of the image data signal, the capacitor 63 is charged according to the potential of the image data signal, and the driving transistor 62 is turned on. The driving transistor 62 has a drain connected to the power supply line 67, a source connected to the electrode of the organic EL element 60, and is induced from the power supply line 67 according to the potential of the image data signal applied to the gate. Current is supplied to the EL element 60.

When the scanning signal moves to the next scanning line 55 by the sequential scanning of the control unit B, the driving of the switching transistor 61 is turned off. However, even when the driving of the switching transistor 61 is turned off, since the capacitor 63 maintains the potential of the charged image data signal, the driving of the driving transistor 62 remains on, and the application of the next scanning signal is performed. Until the organic EL element 60 continues to emit light. By sequential scanning, when a scanning signal is next applied, the driving transistor 62 is driven in accordance with the potential of the next image data signal in synchronization with the scanning signal, and the organic EL element 60 emits light. That is, the light emission of the organic EL element 60 is achieved by providing the switching transistor 61 and the driving transistor 62 as active elements for the organic EL element 60 of each of the plurality of pixels, and the plurality of pixels 53 (Not shown in Fig. 4, but shown in Fig. 3.) Each organic EL element 60 emits light. This light emission method is called an active matrix method.

Here, the light emission of the organic EL element 60 may be light emission of a plurality of gradations by a multi-valued image data signal having a plurality of gradation potentials, or a predetermined amount of light emission by a binary image data signal may be turned on or off.

In addition, the potential of the capacitor 63 may be maintained until the application of the next scanning signal, or discharge may be performed immediately before the application of the next scanning signal.

In the present invention, it is not limited to the above-described active matrix method, and a passive matrix type light emission drive may be employed in which the organic EL element emit light according to the data signal only when a scan signal is scanned.

5 is a schematic diagram of a display device using a passive matrix system. In FIG. 5, a plurality of scanning lines 55 and a plurality of image data lines 56 are provided in a lattice shape to face each other with a pixel 53 interposed therebetween. When a scanning signal of the scanning line 55 is applied by sequential scanning, the pixels 53 connected to the applied scanning line 55 emit light in accordance with the image data signal. In the passive matrix system, there are no active elements in the pixel 53, and manufacturing cost can be reduced.

Example

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

[Example 1]

The shadow mask for the light emitting layer was taken out from the evaporation apparatus, washed with tetrahydrofuran (THF), and a mixture of the host compound and the dopant was recovered. In addition, as the shadow mask, a host compound (compound A) and a dopant (compound B) were deposited at a deposition rate ratio of 20:3, respectively. The recovered solution was concentrated under reduced pressure to about 0.05% by mass to obtain a recovered solution A. In this recovery solution A, 10 mL was each recovered by the method shown below, and the purity of the host compound and the dopant was determined.

In addition, the mass% of the solution was calculated|required from UV absorption spectrum measurement. Specifically, using a high-purity compound previously repeated by recrystallization and gel permeation chromatography, the UV absorption spectrum was measured to prepare a calibration curve in the lean concentration region. Further, a part of the concentrated recovery solution was diluted, the UV absorption spectrum was measured, the concentration was calculated using the calibration curve in the lean concentration region obtained in advance, and the concentration and dilution obtained from the calibration curve were converted into mass%. In addition, the purity of the compound was separately ^{measured by HPLC or a supercritical chromatography instrument (UPC 2} , manufactured by Nippon Waters) by UV absorption chromatography at 254 nm, and calculated as a simple area ratio between the target peak and other peaks.

<Recrystallization method>

While stirring 10 mL of the recovered solution A, 10 mL of methanol was gradually added thereto, and since a solid precipitated, this was filtered out. When the filtrate was confirmed by thin layer chromatography (TLC), spots derived from the host compound and the dopant were confirmed, and it was found that the host compound and the dopant were not separated.

<Gel Permeation Chromatography>

1.0 mL of the recovery solution A was collected using a recycled preparative HPLC system (manufactured by Nippon Bunseki Kogyo Co., Ltd.) equipped with two gel permeation preparative columns having an inner diameter of 40 mm and a length of 600 mm, and the mobile phase was THF and the flow rate was 15 mL/min. Was done. One cycle required about 1 hour, and the mobile phase was recovered for about 10 minutes before and after the two main peaks while discarding the mobile phase. The two main peaks have different dissolution rates, and peak overlap is expected at about the 7th cycle, so the peak with a fast dissolution rate was recovered at the 6th cycle, and they are dopants, and the other peak is recovered at the 7th cycle. One bar was a host compound. Until the end of the 7th cycle, the waste amount of solvent required is about 3.8 L, and it is estimated that about 38 L of solvent is required to process 10 mL of the recovered solution. Further, when the purity of the recovered host compound was confirmed by HPLC, it was 99.8%, and the purity of the dopant was 97.2%. Further, only the dopant was purified by repeating 10 cycles again under the same conditions, whereby the purity could be set to 99.7%.

<Column Chromatography Method>

In a chromatography tube having an inner diameter of 3.0 cm and a height of 150 cm, an eluent composition of tetrahydrofuran: ethyl acetate: heptane = 1:8:2 was used, and silica gel (manufactured by Fuji Silysia Chemical Co., Ltd.) was installed in a conventional manner, and an open column Was produced. When 10 mL of the recovery solution A was recovered and purified using the column and the eluent, the host compound and the dopant were sequentially eluted. In this method, about 4 L of eluent was required until the dopant was eluted. Further, when the purity of the recovered host compound was confirmed by HPLC, it was 97.2%, and the purity of the dopant was 92.0%.

<Liquid chromatography method>

Using a liquid chromatography apparatus (HPLC) equipped with a column (ODS-3, manufactured by GL Science) having an inner diameter of 4.6 mm and a length of 250 mm, the mobile phase was recovered under a gradient condition of methanol:water=9:1 to 3:1. Done. In addition, the column temperature was 40°C, the liquid feeding rate was 1.0 mL/min., and the detection wavelength was 254 nm. The sample injection amount was set to 20 μL, and it took about 15 minutes (including the time to return the gradient) for one chromatographic cycle, and the host compound and the dopant were sequentially eluted.

From the above, when the number of chromatographic cycles required to recover all 10 mL of the recovered solution A is estimated to be 500, the required amount of solvent is 7.5 L, and the time taken is calculated as 125 hours. Further, when the purity of the recovered compound was separately confirmed by HPLC, the purity of the host compound was 99.7%, the purity of the dopant was 99.2%, and high purity recovery was possible.

<Supercritical chromatography method (1)>

A supercritical chromatography apparatus (SFC, manufactured by Nippon Waters) equipped with a column (Torus 2-PIC, manufactured by Nippon Waters) having an inner diameter of 4.6 mm and a length of 250 mm was used, and the mobile phase was methanol:CO ₂ =1:9 Recovery was performed under the gradient conditions of to 3:7. In addition, the column temperature was 40°C, the liquid feeding rate was 2.0 mL/min., the pressure was 15 MPa, and the detection wavelength was 254 nm. The injection volume of the sample was 40 μL, and it took about 8 minutes (including the time to return the gradient) for one chromatographic cycle, and the host compound and the dopant were sequentially eluted.

From the above, when the number of chromatographic cycles required to recover all 10 mL of the recovered solution A is estimated to be 250, the required amount of solvent is 800 mL (only methanol), and the time taken is calculated as 33 hours. Further, when the purity of the recovered compound was separately confirmed by HPLC, the purity of the host compound was 99.8%, the purity of the dopant was 99.7%, and high purity recovery was possible.

<Supercritical chromatography method (2)>

In the supercritical chromatography method (1), compared to the HPLC method, tailing of the dopant was small, and the dead volume was estimated to be 1.0 mL. For the purpose of shortening the chromatographic cycle, a treatment for returning the gradient from 3:7 to 1:9 immediately after attenuation of the dopant peak was performed, and a new sample was injected. It was possible to shorten the required time from 8 minutes to 6 minutes. When the amount of solvent and time required to recover all 10 mL of the recovery solution A were calculated based on the supercritical chromatography method (1), an improvement of 25% was expected in all. In addition, when the purity of the recovered host compound and dopant was separately confirmed by HPLC, it was the same as that of the sample recovered by the supercritical chromatography method (1).

[Example 2]

From the vapor deposition apparatus, the shadow mask for the light emitting layer was taken out, washed with xylene, and a mixture of the host compound and the dopant was recovered. In addition, as the shadow mask, a host compound (compound C below) and a dopant (compound D below) were each deposited at a deposition rate ratio of 100:7. The recovered solution was concentrated under reduced pressure to about 0.5% by mass to obtain a recovered solution B. This recovery solution B was recovered by each of the following methods, and the purity of the host compound and the dopant was determined.

<Liquid chromatography method>

A liquid chromatography apparatus (HPLC) equipped with a column (ODS-3, manufactured by GL Science) having an inner diameter of 4.6 mm and a length of 250 mm was used, and the mobile phase was recovered using acetonitrile. In addition, the column temperature was 40°C, the liquid feeding rate was 1.0 mL/min., and the detection wavelength was 254 nm. Two peaks appear in the chromatogram, and the eluent corresponding to each was recovered. When the purity of the recovered eluent was separately confirmed by a supercritical chromatography instrument, the purity of the host compound was 96.7%, and the purity of the dopant was 97.2%.

<Supercritical chromatography method>

A supercritical chromatography apparatus (SFC, manufactured by Nippon Waters) equipped with a column (Torus 2-PIC, manufactured by Nippon Waters) having an inner diameter of 4.6 mm and a length of 250 mm was used, and the mobile phase was methanol:CO ₂ =3:7 Recovery was performed under the conditions of. In addition, the column temperature was 40°C, the liquid feeding rate was 2.0 mL/min., the pressure was 15 MPa, and the detection wavelength was 254 nm. Two peaks appear in the chromatogram, and the eluent corresponding to each was recovered. When the purity of the recovered eluent was separately confirmed by a supercritical chromatography instrument, the purity of the host compound was 99.6%, the purity of the dopant was 99.4%, and high purity recovery was possible.

[Example 3]

The adhesion-resistant plate was taken out from the vapor deposition apparatus, and the adhesion component was dissolved and recovered in chlorobenzene to obtain a recovery solution C. To the anti-rust plate, α-NPD as a hole transport material, a host compound (the compound A) and a dopant (the compound B), and the following compound ET-1 as an electron transport material were adhered.

With respect to the recovered solution C, recovery was performed in the same manner as in the method described in Example 1 using a liquid chromatography method, but overlapping of chromatographic peaks occurred. Similarly, when the recovered solution C was recovered in the same manner as in Example 1 by using a supercritical chromatography method, a chromatograph in which four peaks were separated was obtained, and it was possible to separate and recover each of the four materials.

[Example 4]

The host compound and the shadow mask for the light emitting layer to which the dopant is adhered were recovered to obtain recovery solutions D to I. The host compound and the dopant were recovered by the method of <supercritical chromatography (1)> of Example 1. The host compound and dopant contained in the recovery solution are shown below. In addition, the dopant concentration of each of the recovered solutions was 6.0% by mass.

Table 2 shows the dopant purity of the recovered eluent according to the following criteria.

<Recovered dopant purity>

◎: 99.5% or more

○: 99.0% or more and less than 99.5%

△: 95.0% or more and less than 99.0%

×: less than 95.0%

In addition, for levels X-2, X-5 and X-6 with high purity of the recovered dopant, in the same manner as in the <supercritical chromatography method (2)> of Example 1, the gradient immediately after the dopant peak attenuated. When a new sample was injected while performing the recovery treatment, the peaks did not overlap, and the time required for one chromatographic cycle could be shortened.

From the above, it is understood that in the recovery from a mixture containing a plurality of materials for an organic EL device, the supercritical chromatography method can effectively recover regardless of the host compound species and dopant. In addition, it can be seen that further improvement of the recovery efficiency is possible when the molecular weight difference between the host compound and the dopant is 200 or more.

[Example 5]

<Production of organic EL element 101>

(Formation of anode)

After patterning was performed on a substrate (NA45 manufactured by AvanStrate Co., Ltd.) on which 100 nm of indium tin oxide (ITO) was deposited on a 100 mm×100 mm×1.1 mm glass substrate as an anode, the transparent support substrate provided with this ITO transparent electrode was isometrically formed. It ultrasonically cleaned with propyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

(Formation of hole injection layer)

On this transparent support substrate, using a solution obtained by diluting poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT/PSS) with pure water, under the conditions of 3000 rpm for 30 seconds, a thin film was formed by spin coating. After formation, it was dried at 200° C. for 1 hour to prepare a hole injection layer having a thickness of 20 nm.

(Formation of hole transport layer)

The transparent support substrate was fixed to a substrate holder of a commercially available vacuum evaporation apparatus, and 250 mg of α-NPD, 200 mg of H-1, and 200 mg of ET-1 were placed in each of a molybdenum resistance heating boat, and installed in a vacuum evaporation apparatus. .

Subsequently, the vacuum ^{bath was decompressed to 4×10 −4} Pa, and then heated by energizing the heating boat into which α-NPD was introduced, and deposited on the hole injection layer at a deposition rate of 0.1 nm/sec to prepare a 20 nm hole transport layer. .

(Formation of light-emitting layer)

The substrate prepared up to the hole transport layer was moved in a glove box under a nitrogen atmosphere. A coating liquid for forming a light emitting layer of the following composition was mixed, and a thin film was formed by spin coating under conditions of 700 rpm and 25 seconds. Further, it was heated and dried under reduced pressure (5 hpa or less, 80°C for 30 minutes) to form a light emitting layer having a thickness of 50 nm.

<Coating liquid for forming a light-emitting layer>

Host compound (Compound A) 10 parts by mass

Light-emitting dopant (Compound B) 1.2 parts by mass

2200 parts by mass of solvent (normal propyl acetate)

(Formation of hole blocking layer)

The substrate on which the light-emitting layer was formed was returned to a vacuum evaporation apparatus, heated by energizing the heating boat containing the compound H-1, and deposited on the light-emitting layer at a deposition rate of 0.1 nm/sec to prepare a 10 nm hole blocking layer.

(Formation of electron transport layer)

In addition, the compound ET-1 was energized to heat the heating boat, and deposited on the light emitting layer at a deposition rate of 0.1 nm/sec to prepare an electron transport layer of 40 nm.

(Formation of cathode)

Then, without breaking the vacuum, it moves to a separate deposition layer, deposits 0.5 nm of lithium fluoride as an electron injection layer (cathode buffer layer), and further deposits 110 nm of aluminum to form a cathode, thereby fabricating the organic EL device 101. I did.

<Production of organic EL element 102>

In the fabrication of the organic EL device 101, compound A as a host material and compound B as a dopant material contained in the coating solution for forming a light emitting layer were recovered using the <supercritical chromatography method (1)> of Example 1. The organic EL device 102 was fabricated in the same manner except for changing to one material. In addition, the recovery material was used after drying the recovery solution of each of the host material and the dopant material under reduced pressure, followed by sublimation purification.

<Production of organic EL element 103>

In the fabrication of the organic EL device 101, compound A as a host material and compound B as a dopant material contained in the coating solution for forming a light emitting layer were recovered using the <supercritical chromatography method (2)> of Example 1. The organic EL element 103 was fabricated in the same manner except for changing to one material. In addition, a recovery material obtained by drying the recovery solution of each of the host material and the dopant material under reduced pressure was used.

<Evaluation of organic EL elements 101 to 103>

For each organic EL device fabricated as described above, the following evaluation was performed.

(1) Measurement of luminous efficiency

Light emission efficiency was measured at room temperature (25°C) ^{under a constant current density condition of 2.5 mA/cm 2} , and a spectral emission luminance meter CS-2000 (manufactured by Konica Minolta) was used to emit light of each organic EL element. The luminance was measured, and the luminous efficiency (external extraction efficiency) in the current value was determined. When the luminous efficiency of the organic EL device 101 (Comparative Example) is set to 100, the luminous efficiency of the organic EL devices 102 and 103 is a value of 98 to 102, and a decrease in luminous efficiency is not seen even when a recovered material is used. Did.

(2) Measurement of luminescence lifetime

To measure the luminescence lifetime, each organic EL element was continuously driven under the conditions of room temperature 25°C and humidity 40% RH, and the luminance was measured using a spectroscopic radiation luminance meter CS-2000, and the time for the measured luminance to be halved (half reduction) Lifespan) was calculated as a measure of the lifespan. The driving conditions were set to a current value ^{of 10000 cd/m 2} at the start of continuous driving. When the light emission lifetime of the organic EL element 101 (comparative example) was set to 100, the light emission life of the organic EL element 102 was 116, and the light emission life of the organic EL element 103 was 121.

The present invention is a method for recovering a material for an organic electroluminescent device capable of efficiently recovering a material for an organic electroluminescent device from a film forming device such as a mask, and applicable to the organic electroluminescent device for the recovered material And a method of manufacturing a material for an organic electroluminescent device.

11: supercritical fluid
12: pump
13: Modifier
14: injector
15: column
16: column oven
17: detector
18: pressure regulating valve
41: display
53: pixel
55: scan line
56: data line
60: organic EL element
61: switching transistor
62: driving transistor
63: condenser
67: power line
A: display
B: control unit

Claims (6)

Organic electroluminescence obtained by separating and purifying a mixture containing a plurality of organic electroluminescent device materials by a supercritical or subcritical chromatography method to obtain a plurality of separated organic electroluminescent device materials Method for recovering the material for the device. The method for recovering a material for an organic electroluminescent device according to claim 1, wherein a difference in molecular weight between any two materials for an organic electroluminescent device contained in the mixture is 200 or more. The method for recovering a material for an organic electroluminescent device according to claim 1 or 2, wherein the mixture contains at least one organic compound and at least one organic metal complex. The method for recovering a material for an organic electroluminescent device according to claim 3, wherein the organic metal complex is a phosphorescent dopant containing iridium (Ir) or platinum (Pt). The method for recovering a material for an organic electroluminescent device according to claim 1 or 2, wherein the mixture contains at least one of an anthracene derivative, a diarylamine derivative, a pyrene derivative, and a perylene derivative. A step of obtaining a mixture containing a plurality of types of materials for organic electroluminescence devices, and
A step of fractionally recovering an eluate containing an organic electroluminescent device material from the mixture by a supercritical or subcritical chromatography method to obtain a plurality of separated organic electroluminescent device materials
A method for producing a material for an organic electroluminescent device through which the material for an organic electroluminescent device is produced.

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