JP2003338379A - Manufacturing method for ink for organic el positive hole injection layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for ink for an organic EL positive hole injection layer enabling the manufacture of an organic EL display element having excellent positive hole injection property and a long service life and having excellent application property by an ink jet method. <P>SOLUTION: This manufacturing method comprises a process in which an associated body of donor molecule containing polythiophen and its derivative and acceptor molecule containing polystyrene sulfonate and its derivative dialyzes dispersion liquid dispersed in water and a process in which high polymer composed of the same component as the acceptor molecule and having an average molecular weight of 50,000 or more and 1,000,000 or less is added to the dispersion liquid after dialysis at a concentration of 1 to 50 wt.%. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ink for an organic EL hole injecting layer, and in particular, it is possible to produce an organic EL display device having an excellent hole injecting property and a long life.
The present invention relates to a method for producing an ink for an organic EL hole injection layer, which has excellent coating properties by an inkjet method.

[0002]

2. Description of the Related Art Recently, an electroluminescence (EL) element using a multilayer film of an organic material has been attracting attention (for example, JP-A-63-264692 and JP-A-63-295).
695, JP-A-1-243393, JP-A 1-24
5087). The organic EL element is roughly classified into two methods, that is, a method of vacuum-depositing low molecules and a method of applying a polymer solution. The method of applying a polymer solution is easy to increase the area, and is particularly suitable for manufacturing a high-definition, large-screen full-color display by an inkjet process.

In the polymer organic EL device, a hole injection layer is provided to reduce the applied voltage. This hole injection layer is formed by applying an ink in which an aggregate of a donor molecule and an acceptor molecule is dispersed in water. However, since the surface tension of the ink is as high as 70 dyn / cm, in a film forming process such as inkjet film forming,
It is difficult to apply with good wettability. Further, if the weight ratio of the ink aggregates is increased in order to increase the viscosity, there is a problem that the film thickness after application is increased in the hole injection layer, and the applied voltage to the organic EL element is increased.

[0004]

An object of the present invention is to provide an organic EL hole which is excellent in hole injection property, can produce an organic EL device having a long life without uneven brightness, and is excellent in coating property by an inkjet method. An object of the present invention is to provide a method for producing an ink for injection layer.

[0005]

A method for producing an ink for an organic EL hole injection layer according to an aspect of the present invention is directed to a donor molecule containing polythiophene and its derivative and an acceptor molecule containing polystyrene sulfonic acid and its derivative. The step of dialysis of the dispersion liquid in which the association with is dispersed in water, and 1% by volume of a polymer having the same component as the acceptor molecule and having an average molecular weight of 50,000 to 1,000,000 in the dispersion liquid after dialysis. The method is characterized by comprising the step of adding at a concentration of 50% by volume or less.

In the method for producing an organic EL hole injecting layer ink according to another aspect of the present invention, an aggregate of a donor molecule containing polythiophene and its derivative and an acceptor molecule containing polystyrene sulfonic acid and its derivative is formed. The step of dialyzing a dispersion liquid dispersed in water, comprising the same component as the acceptor molecule, and having an average molecular weight of 50,000 or more 1
The step of dialyzing a polymer dispersion in which a polymer having a molecular weight of 1,000,000 or less is dispersed in water at a concentration of 1% by weight or more and 50% by weight or less, and the polymer dispersion after the dialysis is added to the dispersion after the dialysis. It is characterized by comprising a step of adding.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The organic EL hole injection layer ink manufactured by the method according to the embodiment of the present invention can be used, for example, for manufacturing the hole injection layer of the organic EL display device shown in FIG.

In FIG. 1, a partition wall 4 made of an insulating material is formed on a transparent substrate 1 having an insulating property such as glass. Each cell separated by the partition wall 4 is formed by a pixel (organic EL element) that exhibits any one of three types of emission colors (R, G, B). That is, on the surface of the substrate 1, a transparent electrode such as ITO (eg, anode) 3, hole transport layers 5, 6, 7, polymer light emitting layer 8, 9 or 10, buffer layer 11, cathode (counter electrode) 12, silver electrode 13 are formed.
The three organic EL elements sequentially formed are separated and formed by the partition wall 4. The polymer light emitting layer 8 is made of a material that emits red (R) light as a dye molecule at the center of light emission, the polymer light emitting layer 9 is made of a material that emits light of green (G) as a dye molecule at the light emission center, and the polymer light emitting layer 10 is made to emit light. A material exhibiting blue (B) emission is used as the central dye molecule. These organic EL elements are respectively connected to the transistors 2 formed on the substrate 1, and the sealing film 14 is further formed on the uppermost layer.

A desired color is emitted from the polymer light emitting layer 8, 9 or 10 by applying a voltage between the transparent electrode and the counter electrode of any one of the organic EL elements by the transistor 2 as appropriate. That is, the holes supplied from the transparent electrode 3 pass through the hole transport layers 5, 6, 7 to the polymer emission layer 8, 9 or 10, and the electrons supplied from the cathode 12 pass through the buffer layer 11 and the polymer emission layer 8, 9. Or reach 10. As a result, holes and electrons are recombined in the polymer light emitting layer to generate light emission, and this desired color can be observed from the transparent substrate 1 side. By arranging such pixels two-dimensionally, the organic EL display device shown in FIG. 1 can be manufactured.

In the embodiment of the present invention, a dispersion liquid in which an aggregate of a donor molecule and an acceptor molecule is dispersed in water is used for producing an ink for an organic EL hole injection layer. The donor molecule is preferably polythiophene and its derivative, and the acceptor molecule is preferably polystyrenesulfonic acid and its derivative. Specifically, the donor molecule is preferably a conductive polymer such as polythiophene, polyaniline or polypyrrole. Further, as the donor molecule, poly (3,4-dialkoxythiophene), which has little light absorption in the visible region, is more preferable. As the acceptor molecule, an acidic polymer such as polyacrylic acid or polystyrene sulfonic acid is preferably used.

According to the embodiment of the present invention, the ink for organic EL hole injection layer has an association between a donor molecule containing polythiophene and its derivative and an acceptor molecule containing polystyrene sulfonic acid and its derivative in water. In the step of dialysis of the dispersed dispersion, and in the dispersion after dialysis, 1% by volume of a polymer composed of the same component as the acceptor molecule and having an average molecular weight of 50,000 or more and 1,000,000 or less.
It is manufactured by a method including a step of adding the above in a concentration of 50% by volume or less.

The water in which the donor molecule and the acceptor molecule are dispersed can be pure water, ion-exchanged water, or distilled water. Further, at least one alcohol selected from methanol, ethanol, and isopropyl alcohol may be contained. By containing alcohol, heat treatment at a low temperature becomes possible, and the content of water can be reduced, which is also preferable. However, the upper limit of alcohol content is 50 wt% in all solvents.
It is desirable to set it to about%. If it exceeds 50 wt%,
The dispersibility of the PEDOT / PSS ink may decrease.

The dispersion liquid in which the above-mentioned aggregate is dispersed can be dialyzed using a dialysis membrane having a molecular weight cut off of 8,000 to 25,000. For example, Invitrogen
Made by Life Technologies (15961
-022) can be used to measure the amount of non-permeable component by performing a dialysis operation using a large amount of ion-exchanged water for a long period (about 2 weeks). 8,000-2
Small solid components, especially micro-aggregates, that can pass through 5,000 dialysis membranes trigger aggregation. These small solids are unstable and tend to collect and agglomerate. At that time, it is considered that the small solid component acts as a glue to fuse the large aggregates. Further, the presence of the inorganic ion component may promote aggregation.

By performing dialysis to remove small solid components and inorganic ion components, it is possible to obtain an ink which is less likely to aggregate.

Small solid components and inorganic ion components in the dispersion liquid can be removed by an ultrafiltration process, an ion exchange process, or a centrifugation process. These steps are
Any two or more may be used in combination, or may be used in combination with other purification steps.

A polymer having the same component as the acceptor molecule and having an average molecular weight of 50,000 or more and 1,000,000 or less is added to the dispersion liquid after dialysis. The acceptor molecule has surface activity and can increase the viscosity of the dispersion liquid. Therefore, the surface tension of the dispersion liquid can be lowered by proper addition, and the wettability can be improved.

The polymer added here has an average molecular weight of 5
If it is less than 0000, the glass transition temperature is low,
When Joule heat is generated while the device is being driven, some of them exceed the glass transition temperature. Since the element is cooled when it is not used, it partially crystallizes and deteriorates. Although the effect of increasing the viscosity of the dispersion increases as the average molecular weight increases, when the molecular weight exceeds 1,000,000, the dispersion stability in water decreases and precipitation occurs, and the surface flatness of the hole injection layer formed is reduced. Be damaged.

The polymer having an average molecular weight of 50,000 or more and 1,000,000 or less added here is also preferably dialyzed in advance by the above-mentioned method.

When the amount of the polymer added is less than 1% by weight, the effect of sufficiently reducing the surface tension cannot be obtained. Since the viscosity increases as the addition amount increases, it is possible to obtain a viscosity suitable for inkjet. However, if added excessively, the foaming property will increase and stable coating will be impossible, so the upper limit is limited to 50% by weight. The surface tension of the ink after adding the polymer is 20 to
The viscosity is preferably within the range of 65 dyn / cm, and the viscosity is preferably within the range of 7 to 20 mPa · s.

As described above, after dialysis of the dispersion liquid of the donor molecule and the acceptor molecule, the acceptor polymer is further added to the dispersion liquid to obtain the surface tension,
It is possible to finely adjust the viscosity and the like. As a result, desired coating performance can be realized. Since only the polymer having the same composition as the acceptor molecule originally contained in the hole injection layer is further added, the hole injection performance or the life of the EL display device is not adversely affected.

The organic EL hole injection layer ink obtained by adding the polymer may be further dialyzed. In this case, since minute associations and low molecular weight donor molecules or acceptor molecules are removed, dispersion stability in a solution state and surface flatness of the hole injection layer to be formed are further enhanced. It is also possible to remove the aforementioned minute components by an ultrafiltration step, an ion exchange step, or a centrifugal separation step. Among these, dialysis or ultrafiltration is preferable in view of operability and mass productivity. In this case, the molecular weight cut-off of the dialysis membrane or the ultrafiltration membrane is 1200.
It is preferably 0 or more, but even if the molecular weight cutoff is about 3000, it is effective if the ink is used within a relatively short period of time.

In the organic EL hole injecting layer ink manufactured by the method of the embodiment of the present invention, the weight ratio of the solids containing the aggregate of the donor molecule and the acceptor molecule and the polymer is 0. It is preferably not less than 0.4 wt% and less than 2.8 wt%. This will be described with reference to FIG.

FIG. 2 is a graph illustrating the relationship between the solid content weight of the organic EL hole injection layer ink and the light scattering intensity.

As the organic EL hole injecting layer ink, a solution of PEDOT.PSS compound represented by the following chemical formula (1) (stock solution 2.8 wt%) was used. Dialysate this ink,
The correlation between the weight (wt%) of the solid content after dialysis and the light scattering intensity measured by a particle size distribution analyzer was examined. The same stock solution before dialysis was diluted to the same concentration as that dialyzed with pure water.
The solid content weight ratio was obtained by weighing a fixed weight of the organic EL hole injecting layer ink, allowing it to dry, and weighing.

[0025]

[Chemical 1]

It has been confirmed that in the organic EL hole injecting layer ink having a large light scattering intensity, the polymer component aggregates in water, and this aggregation adversely affects the surface flatness and characteristics when formed into a thin film.

In FIG. 2, curve a represents the result for the organic EL hole injection layer ink after dialysis, and curve b represents the result for the organic EL hole injection layer ink obtained by diluting the stock solution. Further, the straight line c shows the limit value of light scattering, which has a good film-forming property and a good life. The light scattering intensity of the organic EL hole injection layer ink after dialysis decreases as the solid content concentration decreases from the state of the stock solution (2.8 wt%) as shown by the curve a. On the other hand, in the organic EL hole injection layer ink prepared by diluting the stock solution with pure water, the light scattering intensity sharply increases as the concentration decreases as shown by the curve b. When the concentration becomes lower, the light scattering intensity gradually decreases, but in the range of less than 2.8 wt% and 0.4 wt% or more,
The light scattering intensity is higher than that of the dialyzed organic EL hole injection layer ink (curve a).

When the solid content weight ratio is less than 0.4 wt%, the viscosity is too small and it becomes difficult to eject by an ink jet, and the formed film may be damaged.

The light scattering intensity, the surface flatness when formed into a film, and the reference values of the physical properties of the thin film are located in the middle of the two, and the organic EL hole injection layer ink diluted with pure water has the light scattering intensity as a reference. Greater than value.

The organic EL hole injection layer ink produced by the method of the embodiment of the present invention has a better dispersibility as the particle size is smaller. Therefore, the hole injection layer formed using such an ink is excellent in surface flatness, uniformity of film quality, and uniformity of physical properties. The present inventors have found that the particle size distribution of the organic EL hole injection layer ink and the organic EL after film formation
As a result of comparison with the life of the device, the following findings were obtained. That is, when the maximum value of the particle size distribution is 0.15 μm or less, and the volume fraction of molecules having a particle size of more than 0.5 μm in the molecule is 5% or less,
The device has a long life. When the particle size is larger than this region, unevenness occurs on the surface of the hole injecting layer after film formation, and light emission is not favorably performed, and the role as the hole injecting layer decreases,
Problems such as deterioration of brightness occur. The maximum value of the particle size distribution is 0.1 μm or less, and the entire particle size distribution is 0.
It is more desirable to satisfy the condition of being within 3 μm.
More desirably, it is ideal that the maximum value of the particle size distribution is 0.01 μm or less, and that the entire particle size distribution is within 0.1 μm.

Furthermore, in the organic EL hole injection layer ink manufactured by the method according to the embodiment of the present invention,
The component that does not pass through the dialysis membrane with a molecular weight cut-off of 12000 is 5
It is more preferably 0% or more, still more preferably 80% or more. However, the molecular weight cut-off is 1
Among the components that pass through the dialysis membrane of 2000, the acceptor molecule has an effect of interacting with the organic EL polymer to lower the hole injection barrier, and the interaction is larger in the low molecular weight one. Therefore, it is desired that the component that does not pass through the dialysis membrane having a cut-off molecular weight of 12000 is 95% or less.

As described above, the ink for an organic EL hole injection layer manufactured by the method according to the embodiment of the present invention contains a predetermined amount of acceptor molecules having an average molecular weight of 50,000 or more and 1,000,000 or less. It has the optimum viscosity and surface tension for inkjet coating. By using such an organic EL hole injecting layer ink, it is possible to apply the ink by an ink jet method with high accuracy to produce a hole injecting layer having good characteristics.

In the organic EL display device shown in FIG.
The thickness of the hole injection layer is preferably 2 to 100 nm,
50 nm is more preferable. If the thickness of the hole injection layer is thinner than 2 nm, a uniform film cannot be obtained, and if it is thicker than 100 nm, visible light is absorbed and the driving voltage is slightly increased.

The thickness of the polymer light emitting layer is about 10 nm.
~ 200 nm is desirable. The thickness of the polymer light emitting layer is 20
If it is thicker than 0 nm, the driving voltage must be increased, and the injected electrons or holes are deactivated to reduce the electron-hole recombination probability and the luminous efficiency of the polymer light emitting layer is lowered. There is a risk. If the thickness is less than 10 nm, it becomes difficult to form a uniform film, which may cause variations in the light emitting property of each element.

A conductive material is used for the anode or the cathode, but a transparent electrode such as ITO is used for the electrode arranged on the light emitting surface side. The substrate on which the organic EL element is formed is not particularly limited, but when the substrate side is used as a light emitting surface, a transparent substrate such as glass is used.

[0036]

EXAMPLES Examples of the present invention will be described below.

Example 1 As shown in FIG. 3, an example in which each pixel (one pixel size is 100 μm square) was formed with a monochromatic organic EL element to manufacture a 2.5 inch square organic EL display device will be described. To do.

First, according to the formulation shown in Table 1 below,
An acceptor molecule having an average molecular weight of 50,000 or more was added to the hole injection layer ink, and the organic E
Ink for L hole injection layer (A1 to H1) was prepared. The ink used to form the hole injection layer is an ink raw material containing a PEDOT.PSS compound represented by the chemical formula (1) (PEDOT ink CH8 manufactured by Bayer Co., Ltd.).
000) was used.

[0039]

[Table 1]

In all of the inks A1 to H1, 50% or more of the solid components in the ink had a cut-off molecular weight of 12000 and did not pass through the dialysis membrane.

A display device was manufactured in the following manner using each of the above inks for hole injection layer. A TFT 2 is formed on a glass substrate 1 by a conventional method, and ITO (indium-tin-oxide), which is a transparent conductive material, is used as an anode 3.
Was formed into a film having a thickness of 50 nm. Further, the partition walls 4 were formed in a lattice shape by a photoresist process. Next, using any of the inks (A1 to H1), a hole injection layer 5 having a thickness of about 20 nm was formed by an inkjet method.

As a material of the polymer light emitting layer 8, poly (3-alkylthiophene) (poly [3-alkylthiophen) of red light emission represented by the chemical formula (2) is expressed.
e]: PAT) was used to form the polymer light emitting layer 8 by an inkjet method.

[0043]

[Chemical 2]

As the buffer layer 11, Li having a thickness of about 3 nm is used.
F was formed by sputtering. A Ca (calcium) having a thickness of about 100 nm is formed thereon as a cathode 12, and a silver electrode 13 having a thickness of about 300 nm is further formed thereon.
Was formed. A sealing film 14 was formed on the outermost surface to seal each pixel.

The organic EL display device manufactured as described above was driven at a current density of 20 mA / cm ² ,
It was confirmed to have a half life of 10,000 hours or more.

Comparative Example 1 Organic EL hole injection layer inks I1 to K1 shown in Table 2 below.
Example 1 described above except that the hole injection layer was prepared using
An organic EL display device was manufactured by a method similar to. The inks J1 and K1 shown in Table 2 were prepared to have a viscosity and surface tension that can be applied by an inkjet method.

[0047]

[Table 2]

As a result, in ink jet coating,
Ink I1 has insufficient ink wettability on the substrate surface,
The ejection from the nozzle was not stable. Ink J1
Is obtained by adding PEG (polyethylene glycol) to increase the viscosity. Although the ejection stability was improved, it was confirmed that the life was shortened due to the deterioration of the hole injection performance. Further, the ink K1 contains Surfynol 104 (manufactured by Air Products and Chemicals) in order to improve the wettability on the substrate. Although the ink was spread uniformly on the substrate and the ejection stability was also improved, the life was shortened due to the deterioration of the hole injection performance as in the case of the ink J1.

Example 2 In this example, the three-color organic EL display device shown in FIG. 1 was manufactured as follows. The TFT 2 is formed on the glass substrate 1 by a conventional method, and ITO (indium-tin-oxide), which is a transparent conductive material, is used as the anode 3 to a film thickness of 5
The film was formed at 0 nm. Further, the partition walls 4 were formed in a lattice shape by a photoresist process. Next, the hole injection layer 5,
The ink E1 shown in Table 1 was used for 6 and 7, and a film having a thickness of 20 nm was formed by an inkjet method. In all cases, the ejection was stable, and the spread of the ink after adhering to the substrate was good.

As the material of the polymer light emitting layer 8, poly (3) emitting red light represented by the chemical formula (2) is used as in Example 1.
-Alkylthiophene) (poly [3-alkylt
The polymer light emitting layer 8 was formed into a film by the inkjet method using a HIPHONE]: PAT).

As a material for the polymer light-emitting layer 9, in the compound represented by the chemical formula (3) which is a host molecule, the compound represented by the chemical formula (4) which is a dye molecule at the luminescence center is added to 0.5.
A polymer light emitting layer 9 for green light emission was formed by an inkjet method using a material doped with wt%.

[0052]

[Chemical 3]

As a material for the polymer light emitting layer 10, poly (9,9′-dialkylfluorene) (poly [9,9′-dialk) that emits blue light represented by the chemical formula (5) is used.
ylfluorene]: PDAF) was used to form a blue light emitting polymer light emitting layer 10 by an inkjet method.

[0054]

[Chemical 4]

As the buffer layer 11, Li having a thickness of about 3 nm is used.
F was formed by sputtering. A Ca (calcium) having a thickness of about 100 nm is formed thereon as a cathode 12, and a silver electrode 13 having a thickness of about 300 nm is further formed thereon.
Was formed. A sealing film 14 was formed on the outermost surface to seal each pixel.

This organic EL display device is set to 20 mA / cm ²
As a result of driving at a current density of 1,200, the luminance half life is 1,200.
It was 0 h. In addition, no display unevenness, which is considered to be caused by inkjet coating, was observed, and good inkjet film formation was realized.

Example 3 The ink (A1) shown in Table 1 above was subjected to the treatment shown in Table 3 below to obtain inks A2 to F2. Furthermore, PEDOT / PSS represented by the above chemical formula (1)
A stock solution ink having a solid content weight of 2.8 wt% was prepared using only the compound, and the G2 to I2 inks were prepared using this.

[0058]

[Table 3]

To check the storage stability of the obtained ink,
It was allowed to stand at 50 ° C. for 1 week, and it was examined whether larger aggregates were formed by light scattering. As a result, larger aggregates were not observed in the inks A2 to F2, and it was confirmed that the inks were stable. On the other hand, in the G2 and H2 inks, larger aggregates were observed, and it was confirmed that they were unstable.

Using each of the above hole-injection-layer inks, a display device was manufactured in the same manner as in Example 1 above.

When the inks A2 to F2 were used, the ink jet was not clogged during the formation of the hole injection layer by the ink jet method. on the other hand,
In the case of using the inks G2 to I2, clogging was likely to occur in the nozzle in the latter half of the film formation of the hole injection layer by the inkjet method, and a high voltage was required to project a predetermined amount.

Table 4 below shows the initial luminance and the luminance half life when the organic EL display device manufactured as described above was driven by a current source of 20 mA / cm ² . It was found that each of the organic EL display devices A2 to F2 in which the hole injection layer was formed using the inks A2 to F2 had a half life of 10,000 hours or more. On the other hand, it was found that the organic EL display devices of G2 to I2 in which the hole injection layer was formed using the inks G2 to I2 did not reach the luminance half life of 5000 hours and were short in life.

[0063]

[Table 4]

The H2 ink has the same concentration as the ink D2 which has undergone the dialysis operation. Ink D2 that has undergone dialysis
Has reached the maximum value of the life in Table 4, while the life of the ink H2 is 3000 hours. Further, the dialysis operation was performed, but the ink I2 having a particularly low solid content concentration had a small initial luminance and a short life. It is considered that this is because the film was too thin and a defect was generated.

Example 4 Ink B2 shown in Table 3 was used for the hole injection layers 5 and 6,
The three-color organic EL shown in FIG. 1 was prepared by the same method as in Example 2 except that the ink D2 was used for the hole injection layer 7.
A display device was manufactured.

This organic EL display device is set to 20 mA / cm ²
As a result of driving at a current density of 1,200, the luminance half life is 1,200.
It was 0 h.

[0067]

As described above in detail, according to the present invention, an organic EL display element having excellent hole injecting property, brightness uniformity and long life can be prepared, and at the same time, an organic compound excellent in ink jet system coating property can be prepared. A method for producing an EL hole injection layer ink can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an organic EL display device using an organic EL hole injection layer ink manufactured by a method according to an embodiment of the present invention.

FIG. 2 is a graph illustrating the relationship between the solid content weight of the organic EL hole injection layer ink and the light scattering intensity.

FIG. 3 is a sectional view showing an organic EL display element in Example 1 of the present invention.

[Explanation of symbols] 1 ... Substrate 2 ... Transistor 3 ... Transparent electrode 4 ... Partition 5 ... Hole injection layer 6 ... Hole injection layer 7 ... Hole injection layer 8 ... Polymer light emitting layer (R) 9 ... Polymer light emitting layer (G) 10 ... Polymer light emitting layer (B) 11 ... Buffer layer 12 ... Counter electrode 13 ... Silver electrode 14 ... Sealing film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor: Sakai             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Katsuyuki Naito             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Yutaka Nakai             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Shintaro Enomoto             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Kazushige Yamamoto             2 shares, 1-9-1 Harara-cho, Fukaya City, Saitama Prefecture             Company Toshiba Fukaya Factory (72) Inventor Nei Mori             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center F-term (reference) 3K007 AB02 AB11 AB18 DB03 EB00                       FA01                 4J039 AD03 AD09 BC07 BC54 BE12                       CA03 CA06 EA46 GA34

Claims (5)

[Claims] 1. A step of dialyzing a dispersion liquid in which an association body of a donor molecule containing polythiophene and its derivative and an acceptor molecule containing polystyrenesulfonic acid and its derivative is dispersed in water, and to the dispersion liquid after the dialysis. ,
An organic EL hole injecting layer comprising a step of adding a polymer having the same component as the acceptor molecule and having an average molecular weight of 50,000 or more and 1,000,000 or less at a concentration of 1% by weight or more and 50% by weight or less. Of manufacturing ink for use. 2. A step of dialyzing a dispersion liquid in which an aggregate of a donor molecule containing polythiophene and its derivative and an acceptor molecule containing polystyrenesulfonic acid and its derivative is dispersed in water, wherein the same component as the acceptor molecule is used. The polymer having an average molecular weight of 50,000 or more and 1,000,000 or less is 1% by weight or more and 5
The method is characterized by comprising: a step of dialyzing a polymer dispersion liquid dispersed in water at a concentration of 0% by weight or less; and a step of adding the polymer dispersion liquid after the dialysis to the dispersion liquid after the dialysis. Method for producing ink for organic EL hole injection layer. 3. The method for producing an organic EL hole injection layer ink according to claim 1, further comprising a step of dialyzing the dispersion liquid to which the polymer is added. 4. The weight ratio of the solid content including the association of the donor molecule and the acceptor molecule and the polymer is set to 0.4 wt% or more and less than 2.8 wt%. The method for producing the organic EL hole injection layer ink according to claim 1. 5. The maximum value of the particle size distribution of all molecules including the association of the donor molecule and the acceptor molecule and the polymer is 0.15 μm or less, and the particle size of the molecule is 0. The method for producing an ink for an organic EL hole injection layer according to claim 1, wherein the volume fraction of molecules larger than 5 μm is 5% or less.