JP5185007B2 - Method for manufacturing organic electroluminescent element and organic electroluminescent element - Google Patents

Description

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

  The organic EL element includes a pair of electrodes (anode and cathode) and a light emitting layer disposed between the electrodes, and is usually formed by sequentially laminating predetermined layers on a substrate. When a voltage is applied to the organic EL element, holes and electrons are injected from the anode and the cathode, respectively, and the holes and electrons injected from both electrodes are recombined in the light emitting layer to emit light. Such an organic EL element can be used for an illumination device or an image display device.

For example, in a display device, a grid-like partition wall (also called a bank) is usually provided on a substrate, and each organic EL element is formed in each pixel region surrounded by the partition wall. For example, the light emitting layer is formed by supplying ink containing a light emitting layer material to each pixel region and further drying.
When the electrode exhibits liquid repellency, the coating liquid applied to the electrode is likely to aggregate, and it may be difficult to uniformly apply the coating liquid on the electrode. In addition, when the partition walls are lyophilic, the coating solution may be dried in a state where it does not fit within the partition walls and protrudes outside the partition walls, and a layer with a uniform thickness cannot be formed within the partition walls. There is. Therefore, conventionally, an organic EL element having a uniform film thickness is formed using a substrate provided with electrodes having lyophilic properties and partition walls having lyophobic properties. As one of the methods for making the electrodes lyophilic and making the partition walls repellent, for example, CF ₄ plasma treatment is used. When CF ₄ plasma treatment is performed on both the inorganic material and the organic material, the organic material is more easily fluorinated than the inorganic material, so that the organic material is selectively lyophobic. By utilizing this property, a substrate provided with an electrode showing lyophilicity and a partition wall showing liquid repellency is realized. Specifically, by performing CF ₄ plasma treatment on a substrate on which an electrode made of an inorganic material such as indium tin oxide (abbreviated as ITO) and a partition wall made of an organic resin are formed. A substrate having electrodes made lyophilic and partition walls made liquid repellent is prepared (for example, Patent Documents 1 and 2).

  On the other hand, when the partition wall is made liquid-repellent, a lower electrode formed on the substrate due to ink droplets repelling on the surface of the partition wall facing the pixel region (hereinafter also referred to as a side surface of the partition wall) The thickness of the light emitting layer may be reduced at the boundary with the light emitting layer. When the upper electrode is formed on such a light emitting layer, the electrical resistance between the upper electrode and the lower electrode is lowered at the boundary portion, and a leak current is likely to occur. In order to avoid this problem, for example, Patent Document 3 discloses an element configuration in which an inorganic insulating film such as silicon oxide covering the periphery of the lower electrode is provided between the lower electrode and the partition. By providing the inorganic insulating film in the portion where the thickness of the light emitting layer is reduced, the withstand voltage at the boundary between the partition wall and the lower electrode can be improved, and electrical leakage is suppressed.

JP 2002-222695 A JP 2000-323276 A JP 2005-203215 A

  Under the circumstances as described above, an object of the present invention is to provide a method for forming a layer by a simple method different from the conventional technique in order to manufacture a highly reliable organic EL element.

In order to solve the above problems, the present invention employs the following configuration.
[1] An organic electro that includes a first electrode, a second electrode, and one or a plurality of organic layers disposed between the first and second electrodes in a pixel region surrounded by a partition provided on the substrate. A method for manufacturing a luminescence device, comprising:
Preparing a substrate on which the first electrode is formed;
A partition arrangement step of arranging a partition wall in which an opening exposing the surface of the first electrode is formed in a region corresponding to the pixel region on a substrate on which the first electrode is formed;
A first lyophilic step of lyophilicizing the surfaces of the first electrode and the partition;
Forming a liquid repellent layer on the surfaces of the first electrode and the partition;
A second lyophilic step of lyophilicizing a portion of the lyophobic layer formed on the surface of the first electrode;
An organic layer forming step of forming the organic layer in a pixel region surrounded by the partition;
Providing a leakage current block layer having an electric resistance equal to or higher than the electric resistance of all organic layers provided between the first and second electrodes in a boundary region between the partition and the organic layer;
A second electrode forming step of providing the second electrode,
The first electrode and the partition are formed of different materials,
The part formed on the surface of the first electrode is made more lyophilic by the second lyophilic step than the part formed on the surface of the partition wall. Form,
Manufacturing method of organic electroluminescent element.
[2] The method for manufacturing an organic electroluminescent element according to [1], wherein at least a surface portion of the first electrode is formed of an inorganic material, and at least a surface portion of the partition is formed of an organic material.
[3] Manufacture of an organic electroluminescent element according to the above [1] or [2], wherein the liquid repellent layer formed in the liquid repellent layer forming step is formed of a material containing a silane coupling material having a fluoroalkyl group. Method.
[4] The liquid repellent layer forming step according to any one of [1] to [3], wherein the liquid repellent layer is formed by a coating method using a coating liquid containing a material for forming the liquid repellent layer. Manufacturing method of organic electroluminescent element.
[5] The method for manufacturing an organic electroluminescent element according to any one of [1] to [4], wherein the first and second lyophilic steps are made lyophilic by ultraviolet ozone treatment.
[6] The method for producing an organic electroluminescent element according to any one of [1] to [5], wherein plasma treatment is performed after the second lyophilic step.
[7] In at least one of the first and second lyophilic steps, the lyophilic step is performed by oxygen plasma treatment.
Plasma treatment is performed after the second lyophilic step.
The manufacturing method of the organic electroluminescent element as described in any one of [1] to [4] above.
[8] The method for producing an organic electroluminescent element according to the above [6] or [7], wherein the plasma treatment is performed in an atmosphere containing a fluorine-containing gas.
[9] In the organic layer forming step, an ink containing a material for forming the organic layer is ejected to a pixel region surrounded by the partition wall by an inkjet method, and the landed ink is solidified to form the organic layer. The manufacturing method of the organic electroluminescent element as described in any one of [1] to [8] above.
[10] In the step of providing the leakage current blocking layer, ink containing a material for forming the leakage current blocking layer is ejected to a pixel region surrounded by the partition wall by an ink jet method, and the landed ink is solidified to form the leakage current. The method for producing an organic electroluminescence element according to any one of [1] to [9], wherein the current blocking layer is formed.
[11] The method for producing an organic electroluminescent element according to the above [10], wherein in the step of providing the leakage current block layer, the landed ink is cured by crosslinking with heat or light.
[12] An organic electroluminescence device produced by the production method according to any one of [1] to [11].
[13] The organic electroluminescence according to [12], wherein the planar shape of the pixel region is substantially oval, and the leakage current blocking layer is provided in a curved portion of the pixel region in plan view. element.
[14] The organic electroluminescence device according to [12] or [13], wherein the leakage current blocking layer has an electrical resistivity of 10 ⁶ Ωcm or more.
[15] The organic electroluminescent element according to any one of [12] to [14], wherein a portion of the liquid repellent layer formed on the first electrode functions as a hole injection layer.

  According to the present invention, the lyophilic region and the lyophobic region are selectively and selectively so that the surface of the first electrode is lyophilic and the surface of the partition wall is lyophobic. It can be formed easily. In addition, according to the present invention, an organic EL element in which a leak current hardly occurs can be easily produced.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. For ease of understanding, the scale of each member in the drawings may be different from the actual scale. Further, the present invention is not limited by the following description, and can be appropriately changed without departing from the gist of the present invention. In the organic EL device, there are members such as electrode lead wires. However, in the explanation of the present invention, the description is omitted because it is not directly required. For convenience of explanation of the layer structure and the like, in the example shown below, the explanation will be made with the figure in which the substrate is placed below. However, the organic EL element of the present invention and the organic EL device equipped with the organic EL element are not necessarily in the vertical and horizontal directions. It is not necessarily placed in place and manufactured or used.

1. Manufacturing method of organic EL element of the present invention The manufacturing method of the present invention includes a pixel region surrounded by a partition wall and is located at least between the first electrode, the second electrode, and the first and second electrodes. It is a method of manufacturing an organic electroluminescence device comprising a plurality of organic layers. In the manufacturing method of the organic EL element of this invention, at least the following process is included.
(1) Step of preparing a substrate on which the first electrode is formed (2) A partition wall in which an opening exposing the surface of the first electrode is formed in a region corresponding to the pixel region, A partition arrangement step of arranging on the substrate on which is formed,
(3) A first lyophilic process for lyophilic treatment of the surfaces of the first electrode and the partition wall (4) A liquid repellent layer forming process for forming a liquid repellent layer on the surfaces of the first electrode and the partition wall (5) A second lyophilic process for lyophilic treatment of a liquid repellent layer portion covering the liquid repellent layer formed on the surface of the first electrode in the pixel region surrounded by the partition wall (6) Surrounded by the partition wall Organic layer forming step (7) for forming the organic layer in the pixel region provided In the boundary region where the side wall portion of the partition wall and the light emitting layer organic layer are adjacent to each other, at least between the first and second electrodes A step of providing a leakage current blocking layer having an electrical resistance equal to or higher than the electrical resistance of all the light-emitting layers of the organic layers to be formed;

  As described in detail below, the organic EL element can be provided with various layer configurations and attachment members. Although the production method of the present invention includes at least the steps (1) to (8), other steps may be added. Other steps may be provided before and after the steps (1) to (8), or may be interposed between the steps (1) to (8).

  In the manufacturing method of the present invention, the first electrode and the partition are formed of different materials, and the liquid repellent layer provided in (4) above is formed on the first electrode rather than the portion formed on the surface of the partition. The formed part is formed of a material that is made more lyophilic in the second lyophilic step. In the second lyophilic step (5), a lyophilic treatment is performed to cause a difference in the degree of lyophilicity on the surface of the liquid repellent layer due to the difference in material between the first electrode and the partition wall. As described above, while the liquid repellent layer is provided with the same material on both the first electrode and the partition wall, the liquid repellency is changed depending on the difference in the material of the contacted layer. Thus, lyophilicity or liquid repellency can be adjusted for each desired region without separately coating a plurality of materials having different liquid repellency.

  Although it is not always easy to industrially produce a thin film in the boundary region between the barrier rib and the light emitting layer with a high yield as designed, according to the manufacturing method of the present invention, it is easy to provide a leakage current blocking layer at a predetermined position. By means, an organic EL element with high yield and high reliability can be manufactured.

1.1. First Embodiment of Manufacturing Method FIGS. 1-1 to 1-4 schematically show each step S (a) to step S (l) of an organic EL element manufacturing method according to an embodiment of the present invention. FIG.
First, as shown in step S (a) of FIG. 1A, the first electrode 20 is provided on the substrate 10. The first electrode 20 may be an anode or a cathode, and a second electrode is provided later so as to form a pair. As the substrate 10, one that does not change in each step of manufacturing an organic EL element to be described later is suitably used. For example, glass, plastic, a polymer film, a silicon substrate, and a laminate of these can be used.

  The first electrode 20 is formed of a material different from the partition formed in a later step, and in the present embodiment, at least the surface portion is made of an inorganic material. The first electrode 20 is made of, for example, a material constituting an anode or a cathode to be described later, specifically, a transparent conductive material such as indium tin oxide (abbreviated as ITO), a metal material, or a metal oxide material. Etc. The first electrode 20 is formed in a predetermined shape on the surface of the substrate by, for example, a sputtering method or a vapor deposition method.

  Next, the partition wall 31 is formed as shown in steps S (b) to S (d) of FIG. In the present embodiment, the first electrode 20 is formed of an inorganic material, and the partition wall 31 is formed of a (first) organic material. First, as shown in step S (b), a coating liquid containing a photosensitive resin is applied on the substrate 10, and the photosensitive resin layer 30 is provided on the entire surface of the substrate 10. In this embodiment, a case where a positive photosensitive resin is used will be described. Next, as shown in step S (c), a predetermined region is irradiated with light Ir1 through a photomask 90. Specifically, the region where the opening is formed is irradiated with light. Next, as shown in step S (d), an opening is formed so as to penetrate the region irradiated with light up to the first electrode 20 and expose the surface of the first electrode 20, as shown in step S (d). The portion that remains without being irradiated with the light Ir1 is formed as a partition wall 31.

  A partition wall 31 is provided so as to surround an area corresponding to the pixel area. By providing the partition wall 31, an opening reaching the surface of the first electrode is formed, and a pixel region surrounded by the partition wall 31 is defined. Note that not all of the partition walls need to be provided on the surface of the first electrode, and it is sufficient that at least the peripheral edge of the first electrode is covered with the partition wall 31 when viewed from one side in the thickness direction of the substrate. In the present embodiment, at least the surface of the partition wall 31 is made of an organic material. The partition wall 31 is not particularly limited as long as it is made of an organic material, but it is preferable in terms of manufacturing because it is formed using a photosensitive material such as a photoresist. Examples of the material include novolac positive resist, acrylic negative resist, and photosensitive polyimide.

  Next, as shown in FIG. 1-2, as shown to step S (e), the 1st lyophilic process which makes the surface of the 1st electrode 10 and the partition 31 lyophilic is performed. Examples of the first lyophilic step include ultraviolet ozone treatment and oxygen plasma treatment. In this embodiment, an example of performing ultraviolet ozone treatment is shown, and the entire surface of the substrate 10 is exposed to ultraviolet ozone Ir2. By performing this first lyophilic step, the surface of the first electrode 20 and the partition wall 31 is subjected to a lyophilic process.

  Next, as shown in step S (f), a liquid repellent layer forming step for forming the liquid repellent layer 40 on the surfaces of the first electrode 20 and the partition wall 31 is performed. In the liquid repellent layer 40 formed in this step, the portion formed on the first electrode 20 is more formed by the second lyophilic step described later than the portion formed on the surface of the partition wall 31. Consists of materials that are lyophilic. The liquid repellent layer 40 is formed of an organic material, and preferably includes a silane coupling material having a fluoroalkyl group. Examples of silane coupling materials include nonafluorohexyltrichlorosilane, nonafluorohexyldimethylchlorosilane, nonafluorohexyltrimethoxysilane, nonafluorohexyltriethoxysilane, heptadecafluoro-1,1,2,2-tetrahydroxyltrisilane. Ethoxysilane, heptadecafluoro-1,1,2,2-tetrahydroxytrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane, heptadecafluoro-1,1,2,2- And tetrahydrodecylmethyldichlorosilane and heptadecafluoro-1,1,2,2-tetrahydrodecyldimethylchlorosilane.

  Examples of the method for forming the liquid repellent layer 40 include a spin coat method, a printing method, a slit coat method, and a bar coat method using a solution containing a material that becomes the liquid repellent layer 40 as a coating solution. Among these, it is preferable to use a spin coat method because of the ease of film formation.

  Examples of the solvent of the coating solution for forming the liquid repellent layer 40 include water, methanol, or a mixed solution thereof. The film thickness of the liquid repellent layer is, for example, 0.1 nm to 100 nm, preferably 0.1 nm to 20 nm.

  Next, as shown in step S (g), a second lyophilic process for selectively making the lyophobic layer 40 lyophilic is performed. Examples of the second lyophilic process include ultraviolet ozone treatment and oxygen plasma treatment. Examples of the plasma treatment include plasma treatment under vacuum and plasma treatment under atmospheric pressure. In the present embodiment, as in the first lyophilic step, the entire surface of the substrate 10 and the laminate formed thereon is exposed to ultraviolet ozone Ir3.

  As described above, according to the method for forming a lyophilic liquid repellent pattern as shown in steps S (e) to S (g) shown in FIG. 1-2, the first and second lyophilic processes are performed by ultraviolet ozone treatment. Therefore, the lyophilic liquid repellent pattern can be easily formed as compared with the case where the lyophilic liquid repellent pattern is formed using plasma treatment. Further, as will be described later, the lyophilic portion 41 formed on the first electrode 20 can function as a charge injection layer or a charge transport layer of the organic EL element. Since the charge injection layer or the charge transport layer of the organic EL element is secondarily formed by performing the lyophilic liquid repellent pattern formation method in this way, the lyophilic liquid repellent pattern formation method is organic It can be suitably used as a method for producing a substrate for an EL element.

  As described above, the liquid repellent layer 40 is a material that is made more lyophilic in the second lyophilic step in the portion formed in the first electrode 20 than in the portion formed on the surface of the partition wall 31. It is comprised including. By performing the second lyophilic process, as shown in FIG. 1-2 step S (h), a part of the surface originally provided as the liquid repellent layer 40 at the portion located in contact with the first electrode 20 is formed. A part 41 (sometimes referred to as a lyophilic part 41) is formed in which the surface region R1 has lyophilicity. On the other hand, the liquid repellent layer 40 provided at a position in contact with the partition wall 31 forms a portion 42 (sometimes referred to as a liquid repellent portion 42) in which the surface region R2 maintains liquid repellency as it is. As described above, due to the difference in the base material, a part of the region originally having liquid repellency is selectively made lyophilic. In FIG. 1-2 and the like, the boundary 43 between the region 41 and the region 42 after the second lyophilic process is divided by drawing for convenience, but in reality, the two regions are in an integrated state. Therefore, it is assumed that the boundary 43 is not always clear.

  Next, the light emitting layer 51 made of an organic material is formed. As described above, one or a plurality of organic layers are provided between the first electrode and the second electrode. In the present embodiment, an organic EL element including one light emitting layer 51 as the organic layer. Will be described. In step S (i) of FIG. 1-3, a coating liquid containing an organic light emitting material in an amount larger than the capacity of the region surrounded by the partition wall 31 on the pixel region R1 selectively lyophilic as described above. 50 is applied to the opening surrounded by the partition wall 31. Since the bottom surface of the concave portion is lyophilic, the coating liquid spreads on the bottom surface of the concave portion, and the liquid repellent portion 42 formed on the partition wall 31 exhibits liquid repellency, so that the coating liquid does not spread on the partition wall 31. Swells around the recess. When the coating solution is dried in this state, the coating solution contracts sequentially while being repelled by the liquid repellent portion 42 formed in the partition wall 31 in the drying process, so that all the coating solution is accommodated in the holes, resulting in uniform A light emitting layer 51 having a sufficient thickness can be formed (FIG. 1-3 (step S (j)).

  Next, as shown in FIG. 1C, step S (k), the leakage current block layer 60 is provided. The leakage current block layer 60 is provided in a boundary region between the side surface of the partition wall 31 and the light emitting layer 51. FIG. 2 shows an enlarged view of the boundary region R3 and its periphery. 2 corresponds to a cross-sectional view taken along the line AA in FIG.

  In FIG. 2, a stacked body is formed in the pixel region R <b> 1 by overlapping the substrate 10, the first electrode 20, the lyophilic part 41, the light emitting layer 51, and the second electrode 70. The leakage current block layer 60 is provided in a boundary region R3 between the partition region R2 where the partition wall 31 is formed and the pixel region R1. One end 60 a of the leakage current block layer 60 covers up to the upper surface of the partition wall 31 of the liquid repellent part 42. On the other hand, the end 60b from the light emitting layer 51 of the leakage current blocking layer 60 partially covers the end of the light emitting layer. As shown in the example of FIG. 2, when the side end portion of the light emitting layer 51 is formed by an ink jet method or the like, it may easily aggregate in the central direction of the pixel region, and in that case, the boundary between the light emitting layer 51 and the partition wall 31. In some cases, the region may be formed slightly thinner than the original design. Thus, in the boundary region R3, it may be difficult to make the thickness of the layer completely uniform, and a leakage current may easily occur in this region. By providing the leakage current block layer 60 in the boundary region R3, it is possible to compensate for the problems caused by the difficulty in planarization in layer formation, and to produce an organic EL element that can easily suppress the leakage current and the like.

  Before forming the leakage current block layer 60 by the ink jet method, the surface of the partition wall 31, the surface of the light emitting layer 51, or both of them may be lyophilic. By adjusting the lyophilicity between the liquid repellent part 42 on the partition wall 31 and the surface of the lyophilic part 41 on the light emitting layer 51 and the ink forming the leakage current blocking layer 60, the leakage current blocking layer 60 is formed by an inkjet method. Ink is formed on the light emitting layer 51 while discharging the ink to the pixel region R1 and drying the ink by utilizing the surface tension and the lyophilic or lyophobic action of the member in contact with the ink. The leakage current block layer can be easily formed at a predetermined position by facilitating the assembly to the peripheral portion (the side end portion of the light emitting layer 51 in FIG. 2). In the present embodiment, the liquid repellent part 42 formed on the partition wall 31 maintains strong liquid repellency even after the light emitting layer 51 is formed. It is preferable to lyophilicize at least the surface facing the pixel region. Examples of the lyophilic treatment include UV ozone treatment and oxygen plasma treatment. When the light-emitting layer 51 has low UV resistance, the surface of the light-emitting layer may be covered with a photomask, and only the surface of the partition wall 31 may be subjected to UV treatment.

  The leakage current blocking layer 60 can be formed by providing ink containing an organic material at a predetermined position and solidifying it. For example, in the step of providing the leakage current blocking layer 60, an ink mainly composed of an organic solvent and a polymer resin that is a high-resistance organic material is ejected to the pixel region surrounded by the partition wall by an inkjet method. The ink can be sprinkled up on the inner peripheral surface of the partition wall 31 by utilizing the surface tension of the ink, and can be formed by crosslinking with heat and / or light. At this time, the ink can be poured into a predetermined setting position by, for example, appropriately adjusting the viscosity of the high-resistance organic material.

  Next, as shown in S (l) of FIG. 1-4, the second electrode 70 is provided on the light emitting layer 51. Thereafter, a sealing member (not shown) is used to shield the laminated body composed of the first and second electrodes and the layers sandwiched between them from the outside air and to protect the laminated body from physical impact and the like. May be provided on the second electrode side. For example, the sealing member may be provided by bonding the outer peripheral edge portion of the substrate 10 provided with the laminate and the sealing member.

  The lyophilic portion 41 of the organic EL element formed in this way functions as a hole injection layer as described above. When forming a hole injection layer by a coating method, in the conventional technique, the hole injection layer is formed by dropping a coating solution containing a material that becomes a hole injection layer into a pixel region surrounded by a partition wall. . In contrast, in the present embodiment, the hole injection layer is formed by a simple method called spin coating. For example, in the case of forming a plurality of pixels, it has been necessary to drop a coating solution containing a material that becomes a hole injection layer for each pixel using an inkjet device. In addition, the hole injection layer can be formed in all the pixels, and the hole injection layer can be easily formed. Furthermore, in a display panel composed of a plurality of pixels, it is necessary to provide a step of forming a lyophilic liquid repellent pattern. In the present invention, however, hole injection is inevitably performed through the step of forming the lyophilic liquid repellent pattern. Since the layer is formed, it is not necessary to provide a step of forming the hole injection layer separately from the step of forming the lyophilic liquid repellent pattern, and the manufacturing process can be simplified.

1.2. Second Embodiment of Manufacturing Method In the second embodiment of the manufacturing method, a plasma treatment is further added to the method for forming a lyophilic liquid-repellent pattern in the first embodiment. That is, in the second embodiment, a processing step of performing plasma processing is included after the second lyophilic step.

After the second lyophilic step, the liquid repellent layer is subjected to plasma treatment. The plasma treatment is preferably performed in an atmosphere containing a fluorine-containing gas. Examples of the fluorine-containing gas include SF ₆ and CF ₄ . It is preferred as the plasma processing Among these is a CF ₄ plasma treatment using CF ₄ reactive gas.

  Thus, after the second lyophilic step, the liquid repellent layer becomes more liquid repellent by performing the plasma treatment on the liquid repellent layer. In the present embodiment, the liquid repellent layer is different in the degree of liquid repellency between the part formed on the surface of the first electrode and the part formed on the partition wall, and the part formed on the partition wall is subjected to plasma treatment. Therefore, it is made of a material that is made more liquid repellent. By applying such a plasma treatment, the contact angle of the part formed on the surface of the first electrode in the liquid repellent layer and the contact angle of the part formed on the partition wall in the liquid repellent layer are calculated. The difference increases. When a coating liquid is applied to the opening using a substrate subjected to plasma treatment, a film with a more uniform film thickness can be formed.

  In the case where at least one of the first and second lyophilic steps is lyophilic by oxygen plasma treatment, the lyophobic layer is provided after the second lyophilic step as in this embodiment. It is preferable to subject to plasma treatment.

2. Organic EL element of the present invention The organic EL element of the present invention includes a first electrode, a second electrode, and a light emitting layer positioned between the first electrode and the second electrode in a pixel region surrounded by a partition wall, A liquid repellent layer positioned between the partition wall and the second electrode, a lyophilic layer positioned between the first electrode and the light emitting layer, and between the first electrode and the second electrode, and A leakage current blocking layer is provided in all or part of the boundary line region between the light emitting layer and the surface (sometimes referred to as a side surface) facing the pixel region of the partition wall. The electric resistance in the substrate thickness direction of the leakage current block layer provided in the organic EL element of the present invention is higher than the electric resistance in the substrate thickness direction of the organic layer. In this specification, unless otherwise specified, the electric resistance means an electric resistance in the thickness direction of the substrate.

  The organic EL device of the present invention can be manufactured by the method for manufacturing the organic EL device of the present invention described above. One embodiment of the manufacturing method is as described above. As an embodiment of the organic EL element, an element shown in FIG. Hereinafter, embodiments according to the layer structure of the organic EL element of the present invention will be further described in detail, and embodiments of the material of each layer and the method of forming each layer will be described later.

  In the embodiment of the manufacturing method described above, the organic EL element including one light emitting layer as the organic layer has been exemplified. However, the organic EL element may include a plurality of organic layers, and further include an inorganic layer. Also good.

  One of the first and second electrodes is a cathode and the other is an anode. The first electrode may be a cathode or an anode.

  Examples of the layer provided between the cathode and the organic light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer. When both the electron injection layer and the electron transport layer are provided between the cathode and the organic light emitting layer, a layer close to the cathode is referred to as an electron injection layer, and a layer close to the light emitting layer is referred to as an electron transport layer.

  The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode. The electron transport layer is a layer having a function of improving electron injection from the cathode, the electron injection layer, or the electron transport layer closer to the cathode. The hole blocking layer is a layer having a function of blocking hole transport. In the case where the electron injection layer and / or the electron transport layer have a function of blocking hole transport, these layers may also serve as the hole blocking layer.

  The fact that the hole blocking layer has a function of blocking hole transport makes it possible, for example, to produce an element that allows only a hole current to flow, and confirm the blocking effect by reducing the current value.

  Examples of the layer provided between the anode and the organic light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer. When both the hole injection layer and the hole transport layer are provided, a layer close to the anode is referred to as a hole injection layer, and a layer close to the light emitting layer is referred to as a hole transport layer. As described above, the lyophilic layer provided in contact with the first electrode functions as, for example, a hole injection layer or a hole transport layer.

  The hole injection layer is a layer having a function of improving hole injection efficiency from the anode. The hole transport layer is a layer having a function of improving hole injection from the anode, the hole injection layer, or the hole transport layer closer to the anode. The electron blocking layer is a layer having a function of blocking electron transport. In the case where the hole injection layer and / or the hole transport layer has a function of blocking electron transport, these layers may also serve as an electron blocking layer.

  The fact that the electron blocking layer has a function of blocking electron transport makes it possible, for example, to produce an element that allows only electron current to flow and confirm the blocking effect by reducing the current value.

Examples of layer structures that can be employed as embodiments of the organic EL device of the present invention are shown below.
a) anode / hole transport layer / organic light emitting layer / cathode b) anode / hole transport layer / organic light emitting layer / electron transport layer / cathode c) anode / hole injection layer / organic light emitting layer / cathode d) anode / Hole injection layer / organic light emitting layer / electron injection layer / cathode e) anode / hole injection layer / hole transport layer / organic light emitting layer / cathode f) anode / hole transport layer / organic light emitting layer / electron injection layer / Cathode g) Anode / hole injection layer / hole transport layer / organic light emitting layer / electron injection layer / cathode h) Anode / hole injection layer / organic light emitting layer / charge transport layer / cathode i) Anode / hole injection layer / Organic light emitting layer / electron transport layer / electron injection layer / cathode j) anode / hole injection layer / hole transport layer / organic light emitting layer / electron injection layer / cathode k) anode / hole transport layer / organic light emitting layer / Electron transport layer / electron injection layer / cathode l) anode / hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer / cathode (here, symbol “/ Indicates that the respective layers sandwiching the symbol "/" are adjacently stacked.
Hereinafter, the same applies to the description of the layer structure. )

As another embodiment of the organic EL device of the present invention, the light emitting layer may have two or more organic light emitting layers, and the organic EL device having two organic light emitting layers includes the following: The layer structure shown to m) can be mentioned.
m) Anode / hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer / charge generation layer / charge injection layer / hole transport layer / organic light emission layer / electron transport layer / electron injection layer / Cathode Further, as an organic EL device having three or more organic light emitting layers, specifically, (charge generation layer / charge injection layer / hole transport layer / organic light emission layer / electron transport layer / charge injection layer) As a single repeating unit, a layer structure including two or more repeating units shown in the following n) can be exemplified.
n) Anode / hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer / (the repeating unit) / (the repeating unit) /... / cathode The layer structure p) and q ), Each layer other than the anode, the cathode, and the organic light emitting layer can be deleted as necessary.

  As one embodiment of the organic EL device of the present invention, in order to emit light from the light emitting layer to the outside, all of the light emitting layers are usually arranged on the side from which light is extracted with reference to the light emitting layer. Make the layer transparent. As an example, an organic EL device having a layer structure of substrate / anode / charge injection layer / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode / sealing member will be described. In the case of a so-called bottom emission type organic EL element that is taken out from the side, the substrate, the anode, the charge injection layer, and the hole transport layer are all transparent, and the so-called top that takes out light from the light emitting layer from the sealing member side. In the case of an emission type organic EL element, the electron transport layer, the charge injection layer, the cathode, and the sealing member are all transparent. As an example, an organic EL device having a layer structure of substrate / cathode / charge injection layer / electron transport layer / light emitting layer / hole transport layer / charge injection layer / anode / sealing member will be described. In this case, the substrate, the cathode, the charge injection layer, and the electron transport layer are all transparent, and in the case of a top emission type organic EL device, the hole transport layer, the hole injection layer, the anode, and the sealing member All of the above shall be transparent. Here, the degree of transparency is preferably such that the resurface from which light is emitted to the outside of the organic EL element and the visible light transmittance to the light emitting layer is 40% or more. In the case of an organic EL element that is required to emit light in the ultraviolet region or infrared region, those having a light transmittance of 40% or more in the region are preferable.

  In one embodiment of the organic EL device of the present invention, an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode in order to further improve the adhesion with the electrode or improve the charge injection from the electrode. Further, a thin buffer layer may be inserted into at least one of the above-described layers in order to improve adhesion at the interface or prevent mixing.

  The order of the layers to be laminated, the number of layers, and the thickness of each layer can be appropriately set in consideration of the light emission efficiency and the element lifetime.

Next, the material of each layer constituting the organic EL element and the method for forming each layer will be described more specifically.
<Liquid repellent layer and lyophilic layer>
The liquid repellent layer is provided between the partition wall and the second electrode. The lyophilic layer is provided between the first electrode and the light emitting layer. The liquid repellent layer and the lyophilic layer are provided as a series of layers on both the partition wall and the first electrode as described in the production method of the present invention. In the second lyophilic step, the liquid repellent layer on the partition maintains the liquid repellency as it is, depending on the difference in material between the partition and the first electrode, while the liquid repellent on the first electrode The layer is provided by being modified into a lyophilic layer. From this point of view, this series of layers may be referred to as a liquid repellent lyophilic layer.

  As already described in the embodiment of the manufacturing method, the liquid repellent lyophilic layer is formed, for example, as shown in steps S (f) to S (g) in FIG. As a result, lyophobic lyophilic layers (41, 42) as shown in step S (h) are formed. The liquid repellent layer is preferably formed of a silane coupling material having a fluoroalkyl group. The liquid repellent layer formed of a silane coupling material having a fluoroalkyl group is formed as a layer cured by a coupling reaction of a silane coupling material having a fluoroalkyl group. Examples of silane coupling materials include nonafluorohexyltrichlorosilane, nonafluorohexyldimethylchlorosilane, nonafluorohexyltrimethoxysilane, nonafluorohexyltriethoxysilane, heptadecafluoro-1,1,2,2-tetrahydroxyltrisilane. Ethoxysilane, heptadecafluoro-1,1,2,2-tetrahydroxytrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane, heptadecafluoro-1,1,2,2- And tetrahydrodecylmethyldichlorosilane and heptadecafluoro-1,1,2,2-tetrahydrodecyldimethylchlorosilane.

  The lyophobic lyophilic layer is initially provided as the lyophobic layer, but at least the surface of the portion on the first electrode is lyophilic by the second lyophilic step, and a lyophilic layer is formed. The lyophilic layer is obtained by curing the silane coupling material and further performing a lyophilic treatment.

<Leakage current blocking layer>
The leakage current blocking layer is provided between the first electrode and the second electrode, and is provided in all or part of the boundary line region between the side surface of the partition wall and the light emitting layer. The leakage current blocking layer is provided so as to prevent improper proximity or direct contact between each layer and the electrode so that current leakage does not occur between the first electrode and the second electrode.

  The leakage current blocking layer can be formed by providing ink containing an organic material having a predetermined electric resistance at a predetermined position and solidifying the ink. For example, in the step of forming a block layer, an ink containing an organic solvent and a polymer resin of a high-resistance organic material is used and ejected by an inkjet method, and then crosslinked by heat and / or light to leak current blocking layer Can be formed. At this time, the viscosity of the high-resistance organic material is adjusted as appropriate so that the high-resistance organic material stays at the predetermined position until the drying process after ink ejection.

  Here, as the organic material for forming the leakage current blocking layer, the polymer compound having a crosslinking group is subjected to a treatment such as heating or light irradiation to be crosslinked, and the polymer compound and the crosslinking material are mixed. Examples thereof include a polymer compound which has been crosslinked by a treatment such as heating or light irradiation.

The leak current blocking layer blocks an inappropriate current flow and has a predetermined electric resistance. The leakage current block layer is set to be higher than at least the electric resistance of the light emitting layer. When a preferable electric resistance is shown as a numerical value, it is preferably 10 ⁶ Ωcm or more. By providing the leakage current block layer having such an electric resistance, an inappropriate current flow can be prevented in the boundary region between the partition wall and the laminate. Further, since the leakage current blocking layer can be formed around the side surface of the partition wall by a simple process such as an ink jet method, the image quality can be greatly improved at low cost.

  Considering the normally planned size of the pixel region, the width of the leakage current block layer is preferably 1 μm or more and 10 μm or less as the length in the planar direction of the pixel region from the partition wall toward the center of the pixel region. preferable.

A specific embodiment of the leakage current block layer will be described with reference to FIGS.
FIG. 2 is an enlarged view of a part of the cross-sectional view of FIGS. As shown in FIG. 2, in this embodiment, it is provided in the boundary region R <b> 3 between the side surface of the partition wall 31 and the organic light emitting layer 51. The leak current blocking layer 60 is formed on the liquid repellent portion 42 so as to be along the side surface of the partition wall 31, and is formed on the organic light emitting layer 51 from the upper end portion 60 a near the upper surface portion of the partition wall 31. It covers up to the overlapping end 60b. By providing the leak current block layer at such a position, a leak current that tends to occur in the vicinity of the partition wall can be suppressed.

  3 and 4 are plan views of the pixel region R1 as viewed from above the substrate, and each shows an example of a region where the leakage current block layer 60 is provided. In the embodiment shown in FIG. 3, the leakage current block layer 60 is provided over the entire circumference of the inner peripheral surface of the partition wall 31 facing the pixel region R1.

  On the other hand, in the embodiment shown in FIG. 4, the leakage current block layer 62 is provided only in the curved portions at both ends of the pixel region R <b> 1 having a roughly oval shape (elliptical shape). In some cases, the leakage current is likely to occur in such a curved portion. The present embodiment shows an example in which the leakage current blocking layer 62 is selectively formed in a portion where the risk of leakage current is higher.

  When it is desired to increase the probability of reliability, it is preferable to provide a leakage current block layer on the entire inner periphery as shown in FIG. On the other hand, in the case where it is possible to further specify a portion where leakage current is likely to occur, for example, as shown in FIG. 4, by selectively forming the leakage current blocking layer 62, the cost for using the organic material for the leakage current blocking layer is reduced. Can be reduced and the cost can be reduced.

<Anode>
In the case of an organic EL element configured to take out light from the light emitting layer through the anode, a transparent or translucent electrode is used as the anode. As the transparent electrode or translucent electrode, thin films of metal oxides, metal sulfides, metals, and the like having high electrical conductivity can be used, and those having high light transmittance are preferably used. Specifically, a thin film made of indium oxide, zinc oxide, tin oxide, ITO, indium zinc oxide (abbreviated as IZO), gold, platinum, silver, copper, or the like is used. Among these, ITO, A thin film made of IZO or tin oxide is preferably used. Examples of a method for producing the anode include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method.

  A material that reflects light may be used for the anode, and the material is preferably a metal, metal oxide, or metal sulfide having a work function of 3.0 eV or more.

  The film thickness of the anode can be appropriately selected in consideration of light transmittance and electrical conductivity, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm. .

<Hole injection layer and transport layer>
As the hole injection layer, the above-described lyophobic layer may have its function. For example, as described above, the hole-injecting layer may be formed by a method for forming a lyophilic liquid-repellent pattern.

  Further, another hole injection layer and / or hole transport layer may be formed between the liquid repellent layer and the light emitting layer. The material constituting the hole injection layer or the hole transport layer is not particularly limited as long as it can be formed by a coating method from a solution, but polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, side Polysiloxane derivatives having an aromatic amine in the chain or main chain, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, polyaniline or derivatives thereof, polythiophene or derivatives thereof, polyarylamine or derivatives thereof, polypyrrole or derivatives thereof , Poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof, phenylamine, starburst amine, phthalocyanine, amorphous car Mention may be made of down, polyaniline and the like.

  Among these, hole transport materials include polyvinyl carbazole or derivatives thereof, polysilane or derivatives thereof, polysiloxane derivatives having aromatic amine compound groups in the side chain or main chain, polyaniline or derivatives thereof, polythiophene or derivatives thereof, poly Polymeric hole transport materials such as arylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferred, and polyvinylcarbazole or derivatives thereof are more preferred. , Polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  Further, a hole injection layer different from the liquid repellent layer may be formed between the liquid repellent layer and the electrode on the substrate. In this case, the method for forming the hole injection layer is not particularly limited. In addition to the material formed by the above coating method, an inorganic material such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide is deposited. It can also be formed by a method such as a method, a sputtering method, or an ion plating method.

  In addition, the solvent used for film formation from a solution is not particularly limited as long as it can dissolve a hole injection material or a hole transport material. Chlorine solvents such as chloroform, methylene chloride, dichloroethane, tetrahydrofuran, etc. And ether solvents, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate, and water.

  Examples of the film-forming method from a solution include coating methods such as a micro gravure coating method, a gravure coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, an ink jet printing method, and a nozzle coating method. .

  The film thicknesses of the hole injection layer and the hole transport layer vary depending on the materials used, and are set appropriately so that the drive voltage and the light emission efficiency become appropriate values. It is necessary, and if it is too thick, the drive voltage of the element increases, which is not preferable. Therefore, the film thickness of the hole injection layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

<Organic light emitting layer>
The organic light emitting layer is usually formed of an organic material that mainly emits fluorescence and / or phosphorescence, or the organic material and a dopant that assists the organic material. The dopant is added for the purpose of improving the luminous efficiency and changing the emission wavelength. The organic material may be a low molecular compound or a high molecular compound. Examples of the light emitting material constituting the organic light emitting layer include the following dye materials, metal complex materials, polymer materials, and dopant materials. In the present specification, a polymer has a polystyrene-equivalent number average molecular weight of 10 ³ or more, and a polystyrene-equivalent number average molecular weight of usually 10 ⁸ or less.

(Dye material)
Examples of dye-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, quinacridone derivatives, coumarin derivatives, and the like.

(Metal complex materials)
Examples of the metal complex material include Al, Zn, Be, etc. as a central metal, or rare earth metals such as Tb, Eu, Dy, etc., and oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, as a ligand, Examples include metal complexes having a quinoline structure, such as iridium complexes, platinum complexes and the like, metal complexes having light emission from triplet excited states, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzo Examples include a thiazole zinc complex, an azomethyl zinc complex, a porphyrin zinc complex, and a europium complex.

(Polymer material)
High molecular weight materials include distyrylarylene derivatives, oxadiazole derivatives, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, quinacridone derivatives, coumarin derivatives. And those obtained by polymerizing the above dye-based materials and metal complex-based luminescent materials.

  Among the light-emitting materials, materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

  Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

  Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.

(Dopant material)
Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like. In addition, the thickness of such a light emitting layer is usually about 2 nm-200 nm.

  As a method for forming the light emitting layer, a method of applying a solution containing a light emitting material, a vacuum deposition method, a transfer method, or the like can be used. Examples of the solvent used for film formation from a solution include the same solvents as those used for forming a hole transport layer from the above solution.

Methods for applying a solution containing a light emitting material include gravure coating, spray coating and nozzle coating, as well as gravure printing, screen printing, flexographic printing, offset printing, reverse printing, inkjet Examples of the application method include a printing method. A printing method such as gravure printing method, screen printing method, flexographic printing method, offset printing method, reverse printing method, inkjet printing method, nozzle coating method is preferable in that pattern formation and multicolor coating are easy. In the case of a low molecular compound exhibiting sublimability, a vacuum deposition method can be used. Furthermore, a method of forming a light emitting layer only at a desired place by laser transfer or thermal transfer can be used.
<Electron transport layer>
In the case of an element structure in which a cathode is provided on a substrate, the liquid repellent layer is formed on the upper layer of the cathode.
In this case, the above-described liquid repellent layer can be used as an electron transport layer, and the electron transport layer can be formed by a method for forming a lyophilic liquid repellent pattern.

  In the case where the above-described liquid repellent layer is not used as the electron transport layer as in the structure in which the anode is provided on the substrate, a known material can be used as the electron transport material constituting the electron transport layer, and oxadiazole Derivative, anthraquinodimethane or derivative thereof, benzoquinone or derivative thereof, naphthoquinone or derivative thereof, anthraquinone or derivative thereof, tetracyanoanthraquinodimethane or derivative thereof, fluorenone derivative, diphenyldicyanoethylene or derivative thereof, diphenoquinone derivative, or 8 -A metal complex of hydroxyquinoline or a derivative thereof, polyquinoline or a derivative thereof, polyquinoxaline or a derivative thereof, polyfluorene or a derivative thereof, and the like.

  Among these, as an electron transport material, an oxadiazole derivative, benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, a metal complex of 8-hydroxyquinoline or a derivative thereof, a polyquinoline or a derivative thereof, a polyquinoxaline or a derivative thereof, a polyfluorene Or a derivative thereof is preferable, and 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are further included. preferable.

Examples of the film formation method of the electron transport layer include film formation from a solution or a molten state, and polymer electron transport materials include film formation from a solution or a molten state. In addition, when forming into a film from a solution or a molten state, you may use a polymer binder together. Examples of the method for forming an electron transport layer from a solution include the same film formation method as the method for forming a hole transport layer from a solution described above.
In the case of an element structure in which a cathode is provided on a substrate, an electron transport layer may be further formed between the liquid repellent layer and the light emitting layer by the method described above.

  The film thickness of the electron transport layer varies depending on the material used, and is set appropriately so that the drive voltage and the light emission efficiency are appropriate, and at least a thickness that does not cause pinholes is required, and is too thick. In such a case, the driving voltage of the element increases, which is not preferable. Therefore, the film thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

<Electron injection layer>
In the case of an element structure in which a cathode is provided on a substrate, the liquid repellent layer is formed on the upper layer of the cathode.
In this case, the above-described liquid repellent layer can be used as the electron injection layer, and the liquid repellent layer functioning as the electron injection layer can be formed by the lyophilic liquid repellent pattern forming method as described above.
In the case where the above-described liquid repellent layer is not used as the electron injection layer as in the element structure in which the anode is provided on the substrate, the material that constitutes the electron injection layer is an optimum material according to the type of the light emitting layer. An appropriately selected alkali metal, alkaline earth metal, an alloy containing one or more of alkali metals and alkaline earth metals, alkali metal or alkaline earth metal oxides, halides, carbonates, or of these substances A mixture etc. can be mentioned. Examples of alkali metals, alkali metal oxides, halides, and carbonates include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride , Rubidium oxide, rubidium fluoride, cesium oxide, cesium fluoride, lithium carbonate, and the like. Examples of alkaline earth metals, alkaline earth metal oxides, halides and carbonates include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, barium oxide, Examples thereof include barium fluoride, strontium oxide, strontium fluoride, and magnesium carbonate. The electron injection layer may be composed of a laminate in which two or more layers are laminated, and examples thereof include LiF / Ca.

  The electron injection layer is formed by vapor deposition, sputtering, printing, or the like. The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

<Cathode>
As a material for the cathode, a material having a small work function, easy electron injection into the light emitting layer, and high electrical conductivity is preferable. Moreover, in the organic EL element which takes out light from the anode side, since the light from the light emitting layer is reflected to the anode side by the cathode, a material having a high visible light reflectance is preferable as the cathode material.
For the cathode, for example, an alkali metal, an alkaline earth metal, a transition metal, a group III-B metal, or the like can be used. Examples of the cathode material include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like. A metal, two or more alloys of the metals, one or more of the metals, and one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin An alloy, graphite, or a graphite intercalation compound is used. Examples of alloys include magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, calcium-aluminum alloys, and the like. it can. As the cathode, a transparent conductive electrode made of a conductive metal oxide, a conductive organic material, or the like can be used. Specifically, examples of the conductive metal oxide include indium oxide, zinc oxide, tin oxide, ITO, and IZO, and examples of the conductive organic substance include polyaniline or a derivative thereof, polythiophene or a derivative thereof, and the like. The cathode may be composed of a laminate in which two or more layers are laminated. In some cases, the electron injection layer is used as a cathode.

  The film thickness of the cathode is appropriately set in consideration of electric conductivity and durability, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

Examples of the method for producing the cathode include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded.
<Insulating layer>
Examples of the material for the insulating layer include metal fluorides, metal oxides, and organic insulating materials. As an organic EL element provided with an insulating layer having a thickness of 2 nm or less, an organic EL element having an insulating layer having a thickness of 2 nm or less adjacent to the cathode and an insulating layer having a thickness of 2 nm or less adjacent to the anode are provided. Can be mentioned.

  The organic EL element of the present embodiment can be used as a planar light source, a light source of a segment display device and a dot matrix display device, and a backlight of a liquid crystal display device.

  When the organic EL element of the present embodiment is used as a planar light source, for example, a planar anode and a cathode may be arranged so as to overlap each other when viewed from one side in the stacking direction. In order to construct an organic EL element that emits light in a pattern as a light source of a segment display device, a method of installing a mask having a light-transmitting window formed in a pattern on the surface of the planar light source, There are a method in which the organic layer is formed extremely thick to make it substantially non-light-emitting, and a method in which at least one of the anode and the cathode is formed in a pattern. By forming organic EL elements that emit light in a pattern using these methods and wiring to selectively apply voltage to several electrodes, numbers, letters, simple symbols, etc. can be displayed. A segment type display device can be realized. In order to use the light source of the dot matrix display device, the anode and the cathode may be formed in stripes and arranged so as to be orthogonal to each other when viewed from one side in the stacking direction. In order to realize a dot matrix display device capable of partial color display and multi-color display, a method of separately coating a plurality of types of light emitting materials having different emission colors and a method using a color filter, a fluorescence conversion filter, and the like are used. Good. The dot matrix display device may be passively driven or may be actively driven in combination with a TFT or the like. These display devices can be used as display devices for computers, televisions, mobile terminals, mobile phones, car navigation systems, video camera viewfinders, and the like.

  Furthermore, the planar light source is a self-luminous thin type and can be suitably used as a backlight of a liquid crystal display device or a planar illumination light source. If a flexible substrate is used, it can be used as a curved light source or display device.

  Hereinafter, the present invention will be described in more detail with reference to manufacturing examples and test examples based on the manufacturing process of an actual organic EL element, but the present invention is not limited to the following manufacturing examples.

<Production Example 1: Method 1 for producing organic EL element with liquid repellent layer interposed>
An organic EL device having a layer structure of ITO thin film (anode) / liquid repellent layer (hole injection layer) / intermediate layer / light emitting layer / cathode (Ba layer / Al layer) was produced on the substrate.

A substrate in which an ITO thin film (first electrode) was patterned on a transparent glass substrate was prepared.
Next, photosensitive polyimide (PI) was applied to the entire surface by spin coating and dried to form a 1 μm thick photoresist layer. Next, ultraviolet rays were irradiated to a predetermined area by an alignment exposure machine using a photomask, and the exposed area was removed using a resist developer (manufactured by Nagase Sangyo Co., Ltd .: NPD-18). As a result, a rectangular opening having a width of 100 μm and a length of 300 μm was formed in the photoresist layer. The partition is formed so as to cover the peripheral edge of the ITO thin film.

  Next, heat treatment was performed at 230 ° C. for 1 hour in a clean oven, and the polyimide was completely heated and cured to form an organic insulating layer (partition wall). Thus, a patterning evaluation substrate provided with a partition wall that defines a pixel region in a rectangular shape having a width of 100 μm and a longitudinal length of 300 μm, and a first electrode that exposes the surface of the ITO thin film in an opening defined by the partition wall Was made.

  Next, 1% by weight of nonafluorohexyltrimethoxysilane was mixed with a solvent in which methanol and water were mixed at a weight ratio of 5:95, and the mixture was stirred at room temperature for 15 hours to prepare a liquid repellent layer solution. . Next, the substrate for patterning evaluation was subjected to ultraviolet ozone treatment for 20 minutes on the surface of the substrate using an ultraviolet ozone cleaning apparatus (Technology Vision: UV312), and the entire surface of the substrate for patterning evaluation was subjected to lyophilic treatment ( First lyophilic step).

  Next, the liquid repellent layer solution was applied onto the patterning evaluation substrate by spin coating, and heat treatment was performed on a hot plate at 110 ° C. for 30 minutes to form a liquid repellent layer.

  Next, the substrate for patterning evaluation on which the liquid repellent layer was formed was subjected to ultraviolet ozone treatment on the surface on which the liquid repellent layer was formed for 20 minutes using an ultraviolet ozone cleaning device (manufactured by Technovision: UV312). The entire surface was subjected to lyophilic treatment (second lyophilic process).

  Next, polymer compound 1 was synthesized by the following method. Next, 0.5 wt% of the polymer compound 1 was dissolved in a solvent in which anisole and tetralin were mixed at a weight ratio of 1: 1 to prepare an intermediate layer solution. The intermediate layer solution was applied to the openings formed in the partition walls using an inkjet device. Next, it was dried on a hot plate for 10 minutes, and further subjected to a heat treatment for 20 minutes on a hot plate at 200 ° C. in nitrogen to form an intermediate layer having a thickness of 20 nm.

(Synthesis example of polymer compound 1)
First, 2,7-bis (1,3,2-dioxaborolan-2-yl) -9,9- was added to a separable flask equipped with a stirring blade, a baffle, a length-adjustable nitrogen introduction tube, a cooling tube, and a thermometer. 158.29 parts by weight of dioctylfluorene, 136.11 parts by weight of bis- (4-bromophenyl) -4- (1-methylpropyl) -benzenamine, 27 weights of tricaprylmethylammonium chloride (Aliquat 336 manufactured by Henkel) And 1800 parts by weight of toluene were added, and the temperature was raised to 90 ° C. with stirring while introducing nitrogen from a nitrogen introduction tube. After adding 0.066 parts by weight of palladium (II) acetate and 0.45 parts by weight of tri (o-toluyl) phosphine, 573 parts by weight of a 17.5% aqueous sodium carbonate solution was added dropwise over 1 hour. After completion of the dropwise addition, the nitrogen inlet tube was lifted from the liquid surface and kept under reflux for 7 hours, then 3.6 parts by weight of phenylboric acid was added, kept under reflux for 14 hours, and cooled to room temperature. After removing the reaction solution aqueous layer, the reaction solution oil layer was diluted with toluene and washed with 3% acetic acid aqueous solution and ion-exchanged water.
13 parts by weight of sodium N, N-diethyldithiocarbamate trihydrate was added to the separated oil layer, stirred for 4 hours, then passed through a mixed column of activated alumina and silica gel, and toluene was passed through to wash the column. did. The filtrate and washings were mixed and then added dropwise to methanol to precipitate the polymer. The obtained polymer precipitate was separated by filtration, washed with methanol, and then dried with a vacuum dryer to obtain 192 parts by weight of polymer. The resulting polymer is referred to as polymer compound 1. The polymer compound 1 had a polystyrene equivalent weight average molecular weight of 3.7 × 10 ⁵ and a number average molecular weight of 8.9 × 10 ⁴ .

(GPC analysis method)
The polystyrene equivalent weight average molecular weight and number average molecular weight were determined by gel permeation chromatography (GPC). Standard polystyrene made by Polymer Laboratories was used to prepare a GPC calibration curve. The polymer to be measured was dissolved in tetrahydrofuran to a concentration of about 0.02% by weight, and 10 μL was injected into GPC. The GPC apparatus used was LC-10ADvp manufactured by Shimadzu Corporation. As the column, two PLgel 10 μm MIXED-B columns (300 × 7.5 mm) manufactured by Polymer Laboratories Inc. were used in series, and tetrahydrofuran was flowed at 25 ° C. and a flow rate of 1.0 mL / min as a mobile phase. Absorbance at 228 nm was measured using a UV detector as the detector.

  Next, a light emitting layer was formed on the intermediate layer. First, in a solvent in which anisole and tetralin were mixed at a weight ratio of 1: 1, 1% by weight of a polymer light emitting organic material (BP361: manufactured by Summation) was dissolved to prepare a solution for a light emitting layer. The light emitting layer solution was applied in the opening formed by the partition walls. Furthermore, after application | coating, it dried for 10 minutes on a 100 degreeC hotplate, and produced the light emitting layer.

Next, the substrate was heated in a vacuum (degree of vacuum is 1 × 10 ⁻⁴ Pa or less) at a substrate temperature of about 100 ° C. for 60 minutes. Thereafter, the substrate was formed by vapor deposition without exposing the substrate to the atmosphere. Specifically, the Ba metal is first heated by a resistance heating method to form a Ba layer having a film thickness of 5 nm at a vapor deposition rate of about 0.1 nm / sec. An Al layer having a thickness of 150 nm was formed at 2 nm / sec. Next, after the cathode is fabricated, the substrate is transferred from the vapor deposition chamber to a glove box under an inert atmosphere without being exposed to the atmosphere, and a sealing glass coated with a UV curable resin is pasted in a vacuum state. After that, the pressure was returned to atmospheric pressure and fixed by irradiating with UV to produce a polymer organic EL device.

<Production Example 2: Method 2 for producing organic EL element with liquid repellent layer interposed>
An organic EL device was produced in the same manner as in Production Example 1 except that the plasma treatment was performed after the ultraviolet / ozone treatment (second lyophilic step) after forming the liquid repellent layer in Production Example 1. . In the plasma treatment, CF ₄ gas is used as a reactive gas, and a CF ₄ flow rate is 10 sccm, a gas pressure is 40 Pa, and a power is 40 W using a vacuum dry etching apparatus (Reactive Ion Etching Apparatus Model RIE-200NL manufactured by Samco). For 120 seconds (hereinafter referred to as CF ₄ plasma treatment).

<Production Example 3: Method 3 for producing organic EL element with liquid repellent layer interposed>
In Production Example 1, an organic EL device was produced in the same manner as in Production Example 1 except that the second lyophilic step after the formation of the liquid repellent layer was performed by oxygen plasma treatment and further CF ₄ plasma treatment was conducted. . The oxygen plasma treatment was performed using oxygen gas as a reactive gas. The oxygen plasma treatment was performed for 120 seconds under the conditions of O ₂ flow rate: 40 sccm, gas pressure: 10 Pa, and power: 40 W using a vacuum dry etching apparatus (Reactive ion etching apparatus Model RIE-200NL manufactured by Samco). The CF ₄ plasma treatment was performed under the same conditions as in Production Example 2.

<Production Example 4: Method 4 for producing organic EL element with liquid repellent layer interposed>
In Production Example 1, an organic EL element was produced in the same manner as in Production Example 1 except that the first lyophilic step was performed by oxygen plasma treatment, and the CF ₄ plasma treatment was performed after the second lyophilic step. did. The oxygen plasma treatment and the CF ₄ plasma treatment were performed under the same conditions as in Production Example 3.

<Production Example 5: Method 5 for producing organic EL element with liquid-repellent layer interposed>
In Production Example 1, the first and second lyophilic steps were performed by oxygen plasma treatment, and the organic EL was conducted in the same manner as in Production Example 1 except that CF ₄ plasma treatment was performed after the second lyophilic step. An element was produced. The oxygen plasma treatment and the CF ₄ plasma treatment were performed under the same conditions as in Production Example 3.

(Evaluation 1)
For Production Example 1, after the second lyophilic process, for Production Examples 2 to 5, after the CF ₄ plasma treatment, the liquid repellent layer and anisole (surface tension 35 dyn / cm) formed on the first electrode (ITO thin film) And the contact angle between the liquid repellent layer formed on the partition wall (PI) and anisole. For the measurement of the contact angle, an automatic contact angle measuring device (Eihiro Seiki Co., Ltd .: OCA20) was used.
(Evaluation 2)
In Preparation Examples 1 to 5, after applying the solution for the light emitting layer and further drying for 10 minutes on a hot plate at 100 ° C., the light emitting layer was observed using an optical microscope, and the light emitting layer was formed on one side in the rectangular opening. It was confirmed that no light emitting layer was formed outside the rectangular opening.
(Evaluation 3)
When the ITO thin film and the cathode of each organic EL element produced in Production Examples 1 to 5 were connected to the positive electrode and the negative electrode of the source meter, DC current was injected from the source meter, and the state of the light emitting part was observed. It was confirmed that a luminescent state was obtained.

  Table 1 shows the evaluation results of Evaluations 1 to 3 performed for Production Examples 1 to 5.

  As shown in Table 1, a significant difference is made between the contact angle of the liquid-repellent layer on ITO and the contact angle of the liquid-repellent layer on PI by performing the method for forming the lyophilic liquid-repellent pattern of the present invention. I was able to. Further, by using such a substrate, a light emitting layer having a uniform film thickness can be formed, and furthermore, an organic EL element having a good light emitting state can be produced.

<Production Example 6: Production of an organic EL element having a leakage current blocking layer>
In this production example, an organic EL element in which a leakage current block layer was provided in the peripheral portion of the pixel over the entire circumference was produced.
[Substrate pretreatment]
A substrate on which an ITO electrode pattern was formed on a glass substrate and a partition wall was formed by patterning a photoresist (M302R) manufactured by Sumitomo Chemical was used. The partition size was 170 μm × 50 μm, and the pixel pitch was 237 μm. After cleaning the substrate, the substrate was subjected to surface treatment by a reactive ion etching apparatus (RIE-200L manufactured by Samco). Surface treatment conditions were O ₂ plasma treatment (pressure 5 Pa, output 30 W, O ₂ flow rate 40 sccm, time 10 minutes), followed by CF ₄ plasma treatment (pressure 5 Pa, output 5 W, CF ₄ flow rate 7 sccm, time 5 minutes). went.

[Hole injection layer formation]
As a hole injection layer, 2 wt% 2-butoxyethanol was mixed with PEDOT (HC, CH8000LVW185 manufactured by Stark) and filtered through a 0.45 μm filter. Then, ink jet coating was performed using 80L manufactured by Litrex. At this time, droplets are applied at regular intervals, and the number of droplets per pixel is four. After application, vacuum drying was performed.

[Leakage current blocking layer is formed around the pixel]
An ink in which the heat / photo-curable insulating polymer 1 was dissolved in an organic solvent was used, and inkjet coating was performed using 120L manufactured by Litrex. As an ink additive, DPHA (dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.) by weight ratio, insulating polymer 1: DPHA: Irgacure 907 = 1: 0.25 The ink was prepared so that the insulating polymer 1 was 0.4 wt%. At this time, it filtered with a 1 micrometer filter and set the viscosity to 3 cP. When applying to the whole inside of a partition, about 3-5 drops per pixel were apply | coated to the partition at equal intervals. After application, the insulating polymer was cured by heat treatment at about 200 ° C. for 20 minutes in a vacuum.

[Pretreatment of organic light-emitting layer]
Since the liquid repellent effect of the partition walls disappears due to the heat treatment, CF ₄ plasma treatment (pressure 5 Pa, output 5 W, CF ₄ flow rate 7 sccm, time 1 minute) was performed. Further, in order to reduce water repellency on the cured insulating polymer 1, UV / O ₃ treatment was performed for 1 minute.

[Organic light-emitting layer formation]
The same organic solvent as the insulating polymer 1 was used as a solvent for the light emitting layer ink. GP1302 (manufactured by Summation) was used as the light emitting layer polymer, the ink concentration was 0.8 wt%, and the viscosity was 8 cP. At this time, it filtered and used with the 1 micrometer filter. Thereafter, inkjet coating was performed using 120L manufactured by Litrex. Discharge 7 drops per pixel. After the application, heat treatment was performed in vacuum at about 100 ° C. for 60 minutes.

[Vapor deposition, sealing]
After the heat treatment, the process was shifted to the vapor deposition step without being exposed to the atmosphere, and a cathode was formed by vapor-depositing on the light emitting layer in the order of 100 Å Ba film and 200 Ａｌ Al film. Thereafter, glass sealing was performed.
When an organic EL element was produced by the above method, an organic EL element that operated satisfactorily with reduced leakage current could be obtained.

<Production Example 7: Production of an organic EL element having a leakage current blocking layer>
In this manufacturing example, an organic EL element in which a leak current blocking layer is formed only in a curved portion of a pixel was manufactured.
[Leakage current blocking layer is formed only on the curved part of the pixel]
In the step of forming the leakage current blocking layer of Production Example 6, the ink of the insulating polymer 1 is not formed on the entire periphery of the pixel, but is formed only on the curved portion of the pixel. The device was fabricated as described above. In this case, however, one drop was discharged only at the curved portion of the pixel (in two locations per pixel). The organic EL element of Production Example 7 was able to reduce the amount of ink compared to that of Production Example 6.

It is a figure which shows typically a part of process of one Embodiment of this invention. It is a figure which shows typically a part of process of one Embodiment of this invention. It is a figure which shows typically a part of process of one Embodiment of this invention. It is a figure which shows typically a part of process of one Embodiment of this invention. It is sectional drawing of the organic EL element of one Embodiment of this invention. It is the figure which looked at the pixel area of the organic EL element of one embodiment of the present invention from the opening side of a crevice. It is the figure which looked at the pixel area of the organic EL element of one embodiment of the present invention from the opening side of a crevice.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Board | substrate 20 1st electrode 30 Photosensitive resin layer 31 Partition 40 Liquid-repellent layer 41 Lipophilic part 42 Liquid-repellent part 43 (between the lyophilic part and the liquid-repellent part) Boundary 50 Coating liquid 60, 62 Leakage current blocking layer 70 Second Electrode 90 Photomask R1 Pixel area R2 Partition area R3 Boundary area

Claims (15)

An organic electroluminescence device comprising a first electrode, a second electrode, and one or more organic layers disposed between the first and second electrodes in a pixel region surrounded by a partition provided on a substrate. A method of manufacturing comprising:
Preparing a substrate on which the first electrode is formed;
A partition arrangement step of arranging a partition wall in which an opening exposing the surface of the first electrode is formed in a region corresponding to the pixel region on a substrate on which the first electrode is formed;
A first lyophilic step of lyophilicizing the surfaces of the first electrode and the partition;
Forming a liquid repellent layer on the surfaces of the first electrode and the partition;
A second lyophilic step of lyophilicizing a portion of the liquid repellent layer formed on the surface of the first electrode by treating the entire surface of the liquid repellent layer;
An organic layer forming step of forming the organic layer in a pixel region surrounded by the partition;
After the organic layer forming step, a leakage current blocking layer having an electrical resistance equal to or higher than the electrical resistance of all organic layers provided between the first and second electrodes in a boundary region between the partition wall and the organic layer. Providing, and
A second electrode forming step of providing the second electrode,
The first electrode and the partition are formed of different materials,
The part formed on the surface of the first electrode is made more lyophilic by the second lyophilic step than the part formed on the surface of the partition wall. Form,
Manufacturing method of organic electroluminescent element.   The method for manufacturing an organic electroluminescence element according to claim 1, wherein at least a surface portion of the first electrode is formed of an inorganic material, and at least a surface portion of the partition is formed of an organic material.   The method for producing an organic electroluminescence element according to claim 1, wherein the liquid repellent layer formed in the liquid repellent layer forming step is formed of a material containing a silane coupling material having a fluoroalkyl group.   4. The organic electroluminescence element according to claim 1, wherein in the liquid repellent layer forming step, the liquid repellent layer is formed by a coating method using a coating liquid containing a material for forming the liquid repellent layer. 5. Method.   In the said 1st and 2nd lyophilic process, the manufacturing method of the organic electroluminescent element as described in any one of Claim 1 to 4 lyophilic by ultraviolet ozone treatment.   The manufacturing method of the organic electroluminescent element as described in any one of Claim 1 to 5 which performs a plasma process after a said 2nd lyophilic process. In at least one of the first and second lyophilic steps, lyophilic by oxygen plasma treatment,
Plasma treatment is performed after the second lyophilic step.
The manufacturing method of the organic electroluminescent element as described in any one of Claim 1 to 4.   The method for manufacturing an organic electroluminescence element according to claim 6 or 7, wherein the plasma treatment is performed in an atmosphere containing a fluorine-containing gas.   2. The organic layer is formed by ejecting ink containing a material for forming the organic layer to a pixel region surrounded by the partition wall by an inkjet method in the organic layer forming step, and solidifying the landed ink. The manufacturing method of the organic electroluminescent element as described in any one of 1-8.   In the step of providing the leakage current block layer, ink including a material for forming the leakage current block layer is ejected to a pixel region surrounded by the partition wall by an inkjet method, and the landed ink is solidified to form the leakage current block layer. The manufacturing method of the organic electroluminescent element as described in any one of Claim 1 to 9 which forms.   The method for producing an organic electroluminescence element according to claim 10, wherein in the step of providing the leakage current block layer, the landed ink is cured by crosslinking with heat or light.   The organic electroluminescent element produced with the manufacturing method as described in any one of Claims 1-11.   The organic electroluminescence element according to claim 12, wherein a planar shape of the pixel region is a substantially oval shape, and the leakage current block layer is provided in a curved portion of the pixel region in a plan view. The organic electroluminescence element according to claim 12 or 13, wherein the leakage current blocking layer has an electrical resistivity of 10 ⁶ Ωcm or more. The organic electroluminescent element according to claim 12, wherein a portion of the liquid repellent layer formed on the first electrode functions as a hole injection layer.

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