JP2023060678A - Organic electroluminescent element including metal grid transparent conductive electrode - Google Patents

Abstract

To provide an organic electroluminescent element capable of suppressing problems such as delamination, the organic electroluminescent element being mounted with a metal grid transparent conductive electrode comprising metal wiring, such as a convex thin metal wire, that contains an oxide such as a metal oxide with low acid resistance, and that further has a film thickness greater than the conventional average film thickness.SOLUTION: A metal grid transparent conductive electrode 20 includes a transparent base material 22 and a conductive pattern 24P comprising metal wiring 24 provided on the transparent base material 22. The metal wiring 24 includes a metal and an oxide of the metal. An organic functional layer 40 includes: a doped hole injection layer 42 provided on the conductive pattern 24P and comprising a low molecular organic material; and a hole transport layer 44 provided on the doped hole injection layer 42 and comprising a low molecular organic material. When tTCE represents the thickness of the metal wiring 24 and torg-TCE represents the film thickness of the organic functional layer 40, tTCE is 50 nm or more and 250 nm or less, and (torg-TCE-tTCE) is 50 nm or more and 750 nm or less.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an organic electroluminescence device using a metal grid transparent electrode that suppresses electrical shorts and leak currents, and enables improvement in brightness.

In recent years, organic electroluminescence elements (hereinafter also referred to as “organic EL elements”) have begun to be applied to flat-panel televisions, smartphones, lighting, and the like. An organic EL element has a structure in which an organic functional layer including at least an organic light-emitting layer is arranged between two electrodes facing each other. Since light emitted from the organic light-emitting layer is transmitted through the electrodes and taken out to the outside, at least one of the electrodes is also called a transparent electrode (transparent ductive electrode: hereinafter also referred to as “TCE”), which is essential for the organic EL element. It is a configuration technology of In order to further expand the use of organic EL elements, there is a demand for large area, light weight, and flexible, low-resistance and flexible transparent electrodes.

Conventionally, as a transparent electrode, a transparent electrode using a film made of indium tin oxide (hereinafter also referred to as "ITO") formed on a transparent substrate by a vacuum deposition method or a sputtering method has been widely used. It's here.

However, while ITO itself is a highly transparent material, it has low electrical conductivity. Therefore, in order to realize low resistance, it is necessary to increase the thickness of the ITO film. In addition, the thicker film makes cracks more likely to occur due to deformation such as bending, deflection, and bending. For this reason, it has been difficult to increase the area and flexibility of an organic EL element using ITO as a transparent electrode.

Therefore, research and development of a transparent electrode to replace ITO has been vigorously carried out, and a transparent electrode (hereinafter referred to as "metal grid transparent electrode" or "metal grid TCE") having a conductive pattern composed of fine metal wires on a transparent substrate has been developed. ) is attracting attention. The metal grid transparent electrode has higher flexibility than ITO, which is an oxide, because the fine metal wires exhibit high ductility. Furthermore, since the electrical conductivity of the metal fine wires is higher than that of ITO, the metal grid transparent electrode can obtain a lower sheet resistance than the transparent electrode using ITO when compared at the same transmittance. Furthermore, the metal grid transparent electrode has the advantage that characteristics such as transmittance and sheet resistance can be arbitrarily changed by adjusting the line width and film thickness of the metal thin wires and the gap of the conductive pattern. In addition, although the fine metal wire itself is opaque, it can be made invisible to the human eye by adjusting the line width of the fine metal wire to 3 μm or less, and the transparency of the metal grid transparent electrode can be further improved.

Conventionally, a metal grid transparent electrode composed of fine metal thin wires has been manufactured by a method of patterning a metal deposited film by a vacuum deposition method using a photolithographic technique. As a result, high cost and low productivity were problems.

Against this background, in recent years, high-resolution printing techniques have been developed that are capable of forming extremely fine metal wires with a line width of 3 μm or less, or even submicrons, on transparent substrates. Such additive-type high-resolution printing technology can be easily rolled-to-roll, so that it can achieve industrially high productivity and reduce the environmental load.

However, when a metal grid transparent electrode is used in an organic EL element, a normal organic functional layer is a thin film of 100 nm to 200 nm because carrier mobility is smaller than that of an inorganic semiconductor material. It becomes difficult to cover the convex metal fine wire. Therefore, an electrical short due to contact between the fine metal wire and the opposing cathode, and an increase in leak current due to a shortened distance between both electrodes are likely to occur.

In order to solve this problem, a structure has been proposed in which a transparent conductive inorganic compound such as ITO or ZnO is laminated on a conductive pattern and coated with a thin metal wire to smooth the unevenness of the conductive pattern (for example, , see Patent Document 1). Sufficient flexibility cannot be expected from a structure in which a transparent conductive inorganic compound is laminated on a conductive pattern made of fine metal wires.

Similarly, a conductive polymer such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (hereinafter also referred to as "PEDOT:PSS") is laminated on the conductive pattern as a transparent conductive or hole injection layer. , a structure has been proposed in which unevenness of a conductive pattern is smoothed by coating with a thin metal wire (see, for example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2). Non-Patent Documents 1 and 2 disclose an organic EL device using a metal grid transparent electrode provided with convex metal fine wires of silver or copper with a line width of 3 μm or less manufactured by a vacuum deposition method and a photolithographic technique. there is In these non-patent documents as well, a hole injection layer made of PEDOT:PSS smoothes unevenness of a conductive pattern to realize an organic EL device with a small leakage current. A layer made of a general conductive polymer is formed by, for example, preparing a coating liquid in which PEDOT:PSS is dispersed in an aqueous solvent, printing or coating the coating liquid on a conductive pattern, and drying. be. The PEDOT:PSS water-based coating liquid exhibits strong acidity due to the sulfo group of PSS contained in order to stably disperse the conductive component PEDOT in the water-based solvent.

In addition, in Patent Document 1, a metal adhesion layer made of a metal oxide such as TiO ₂ or ZnO is provided between a metal fine wire printed using an ink containing metal nanoparticles and a substrate, so that the metal fine wire and It is disclosed that the adhesiveness to the substrate is improved, and peeling of the metal fine wires is suppressed during the manufacturing process and during use until the metal fine wires are covered with a transparent conductive layer such as PEDOT:PSS.

WO2016/147481 WO2016/143201 WO2020/027166

F.L.M. Sam et al., Silver grid transparent conducting electrodes for organic light emitting diodes, Org. Electron., Dec. 2014, Vol. 15, P. 3492-3500 J.W. Han et al., Transparent conductive hybrid thin-films based on copper-mesh/conductive polymer for ITO-Free organic light-emitting diodes, Org. Electron., October 2019, Vol. 73, P. 13-17 Peter van de Weijer et al., High-performance thin-film encapsulation for organic light-emitting diodes, Org. Electron., May 2017, Vol. 44, P. 94-98

However, according to the studies of the present inventors, when printing or coating a strongly acidic aqueous coating liquid of PEDOT:PSS on a thin metal wire containing some metal oxides such as copper oxide with low acid resistance, the thin metal wire was damaged, and the thin metal wires were peeled off from the transparent substrate. For example, the mechanism by which cupric oxide, which is one form of copper oxide, dissolves in an aqueous solution containing an organic sulfonic acid such as PSS can be explained by the following reaction formula.

Therefore, it has been found that it is difficult to mount a metal grid transparent electrode provided with metal thin wires containing a metal oxide with low acid resistance in an organic EL device.

In addition, since the metal thin wire formed by the printing method has a form in which the nanostructures generated from the metal nanoparticles are in contact and / or joined together, this specific resistance is higher than that of the metal thin wire made of a single metal using the vacuum deposition method. , for example, tends to be about 10 to 20 times higher. Therefore, in order to reduce the sheet resistance, it is necessary to adjust the film thickness of the convex thin metal wire (that is, the height of the convex portion) to a larger range than before. As a result, it becomes more difficult to incorporate a metal grid transparent electrode formed by a printing method into an organic EL element from the viewpoint of an electrical short circuit and an increase in leakage current.

The present invention has been made in view of the above problems, and includes a convex thin metal wire or the like containing an oxide such as a metal oxide having low acid resistance and having a thickness larger than the conventional average thickness. It is an object of the present invention to provide an organic EL element in which a metal grid transparent electrode made of metal wiring is mounted, which can suppress the above-mentioned problems such as peeling, and an organic EL element which can further improve the luminance. and

The present inventors have made extensive studies to solve the above problems. As a result, the organic functional layer has a doped hole injection layer and a hole transport layer made of a low-molecular-weight organic material, the doped hole injection layer is arranged on the conductive pattern of the metal grid transparent electrode, and the doped hole injection layer is further provided. The inventors have found that the above problems can be solved by increasing the thickness of the hole transport layer so that the total thickness of the organic functional layers is larger than the thickness of the fine metal wires, and have completed the present invention.

That is, the present invention is as follows.
[1] An organic electroluminescence device comprising a metal grid transparent electrode, a cathode facing the metal grid transparent electrode, and an organic functional layer provided between the metal grid transparent electrode and the cathode, The metal grid transparent electrode comprises a transparent substrate and a conductive pattern having metal wiring provided on the transparent substrate, the metal wiring comprising a metal and an oxide of the metal, the organic function a layer provided on the conductive pattern and comprising _a doped hole-injection layer made of a small molecule organic material; a layer provided on the doped hole-injection layer and made of a small molecule organic material; is the thickness of the metal wiring, and t _org-TCE is the thickness of the organic functional layer, t _TCE is 50 nm or more and 250 nm or less, and ( t _org-TCE - t _TCE ) is 50 nm or more and 750 nm or less. .
[2] In the organic electroluminescence element, _WTCE is 0.25 μm or more, where W _TCE is the line width of the metal wiring and G _TCE is the gap between the adjacent metal wirings extending in the same direction. It may be 0 μm or less.
G _TCE may be 50 μm or less.
(G _TCE /W _TCE ) may be 1.0 or more.

[3] In the organic electroluminescence element, where _ATCE is the aperture ratio of the conductive pattern, (G _TCE * _ATCE ) may be 0.6 μm·% or more and 30 μm·% or less.
[4] In the organic electroluminescent device, the conductive pattern may have an aperture ratio _ATCE of 35% or more and less than 100%.
[5] In the organic electroluminescence device, t _HIL may be 30 nm or more and 200 nm or less, where t _HIL is the film thickness of the doped hole injection layer.
[6] In the organic electroluminescence element, t _HTL may be 30 nm or more and 200 nm or less, where t _HTL is the film thickness of the hole transport layer.
[7] In the organic electroluminescence device, σ _HIL may be 5×10 ⁻⁵ S/cm or more, where σ _HIL is the electrical conductivity of the doped hole injection layer.
[8] In the organic electroluminescence device, the sheet resistance of the doped hole injection layer is 6.5×10 ⁹ Ω/sq. The following is fine.
[9] In the organic electroluminescence device, the doped hole injection layer may have a visible light transmittance of 80% or more and 100% or less.
[10] In the organic electroluminescence device, the dopant density N _p of the doped pole injection layer may be 3 vol % or more and 18 vol % or less.
[11] The organic electroluminescence device may further include a transparent conductive inorganic compound layer disposed between the metal grid transparent electrode and the doped hole injection layer.
[12] In the organic electroluminescence device, the transparent conductive inorganic compound layer may contain indium tin oxide.
[13] In the organic electroluminescence element, the metal grid transparent electrode may include a current collector having a second conductive pattern provided on the transparent substrate and electrically connected to the conductive pattern. .

Further, when S _Bus is the occupied area ratio of the second conductive pattern per unit area, S _Bus may be 50% or more and less than 100%.
[14] In the organic electroluminescence device, the metal may be copper.
[15] In the organic electroluminescence element, in STEM-EDX analysis of the metal wiring cross section perpendicular to the extending direction of the metal wiring of the conductive pattern, 0.10 t _TCE from the metal wiring interface on the transparent substrate side. The atomic % ratio O/M _0.10 to _0.90 of the oxygen atoms contained in the oxide of the metal to the metal in the thickness region up to 0.90t _TCE may be 0.01 or more and 1.00 or less.
[16] In the organic electroluminescence element, the conductive pattern may comprise a mesh pattern.
[17] In the organic electroluminescence element, the conductive pattern is formed by printing the ink containing the metal on the surface of the transparent substrate by a plate printing process so as to form the conductive pattern, followed by a baking process. may be formed by fusing the metal such that the printed ink is fired to form a metal component sintered film.
[18] In the organic electroluminescence device, the doped hole injection layer may be made of two or more low-molecular-weight organic materials.
[19] In the organic electroluminescence device, the doped hole injection layer is provided by co-evaporation of a low-molecular-weight host material and a low-molecular-weight dopant so that the dopant density N _p is 3 vol % or more and 18 vol % or less. good too.
[20] In the organic electroluminescence element, each layer constituting the organic functional layer may be made of a low-molecular-weight organic material.
[21] The organic electroluminescence device comprises a second transparent conductive inorganic compound layer provided on the transparent substrate, and the metal grid transparent electrode is provided on the second transparent conductive inorganic compound layer. may be

In the organic electroluminescence element, the metal wiring is provided in a convex shape protruding from the surface of the transparent substrate in contact with the surface of the transparent substrate, and the hole injection layer provided on the conductive pattern. Alternatively, the transparent conductive inorganic compound layer may be provided in contact with at least the upper surface of the metal wiring and the surface of the transparent substrate.

According to the present invention, the metal grid transparent electrode is composed of metal wiring such as convex thin metal wires containing an oxide such as a metal oxide having low acid resistance and having a film thickness larger than the conventional average film thickness. It is possible to provide an organic EL element capable of suppressing the above-described problems such as peeling in the organic EL element mounted with the above, and an organic EL element with further improved luminance.

1 is a top view of an organic EL element according to one embodiment; FIG. Cross-sectional view (schematic drawing) of the organic EL element along A-A' in FIG. FIG. 2 is a top view of a metal grid transparent electrode according to one embodiment; Mesh pattern (square, rectangle, rhombus) of metal grid transparent electrode according to one embodiment Honeycomb pattern of metal grid transparent electrode according to one embodiment Line and space pattern of metal grid transparent electrode according to one embodiment FIG. 2 is a cross-sectional view of a conductive pattern of a metal grid transparent electrode according to one embodiment; JVL characteristics of Example A1 (graph) Appearance photograph of the organic EL element when the applied voltage is 4 V in Example A1 Cross-sectional SEM image of the organic EL device of Example A8 Comparison between simulation of spatial luminance distribution at applied voltage of 4 V and optical microscope image of organic EL element during light emission in Example A1 Graph of G _TCE vs. luminance at different line widths Graph of G _TCE and A _TCE vs. luminance at different line widths Optical microscope image of the organic EL device during light emission of Example C1 at an applied voltage of 4 V

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to this, and various modifications are possible without departing from the scope of the invention. is. The upper limit and lower limit of each numerical range in this embodiment can be combined arbitrarily to form any numerical range. In the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios.
[Organic EL element]

The organic EL element 10 of this embodiment includes a metal grid transparent electrode 20, a cathode 60 facing the metal grid transparent electrode 20, and an organic functional layer 40 provided between the metal grid transparent electrode 20 and the cathode 60. Prepare. The metal grid transparent electrode 20 has a transparent base material 22 and an electrode part composed of a conductive pattern 24P composed of fine metal wires 24 (an example of "metal wiring") provided on the transparent base material 22, The fine metal wire 24 contains a metal component M responsible for conductivity and an oxide of the metal component M. As shown in FIG. The organic functional layer 40 has a doped hole injection layer 42 and a hole transport layer 44 made of low-molecular type organic material, and the doped hole injection layer 42 is disposed on the conductive pattern 24P. When the film thickness t _TCE (FIG. 2) of the metal wire 24 is 50 nm or more and 250 nm or less, and the film thickness of the organic functional layer 40 on the metal wire 24 is t _org-TCE (FIG. 2), (t _org-TCE −t _TCE ), that is, the difference between the film thickness of the organic functional layer 40 and the film thickness of the thin metal wire 24 is 50 nm or more and 750 nm or less.

It should be noted that the “metal thin wires 24 provided on the transparent base material 22” in this specification means only the configuration consisting of the metal thin wires 24 provided on the transparent base material 22 in contact with the surface of the transparent base material 22. First, through another layer provided between the transparent substrate 22 and the metal fine wires 24, a configuration consisting of the metal fine wires 24 provided on the transparent substrate 22 without contacting the surface of the transparent substrate 22. including. For example, a transparent conductive inorganic compound layer may be provided between the transparent substrate 22 and the thin metal wires 24 . Similarly, when an object is placed on top of another object, the object and the other object include cases where they are not in contact with each other.

The organic EL device 10 of this embodiment has a doped hole injection layer 42 and a hole transport layer 44 made of a low-molecular-weight organic material, which are laminated in this order on the conductive pattern of the metal grid transparent electrode 20 . The low-molecular-weight organic materials used for the doped hole injection layer 42 and the hole transport layer 44 can be deposited by vapor deposition. Therefore, for example, even when copper is selected as the metal component M and the metal grid transparent electrode 20 including the metal fine wires 24 containing copper and copper oxide is used, the metal fine wires 24 are not acidic during the manufacturing process of the organic EL element 10. Without being exposed to an aqueous solution or the like, problems such as damage to the fine metal wires 24 and peeling of the fine metal wires 24 from the transparent substrate 22 can be suppressed. In the present specification, the term “low-molecular-weight organic material” is broadly classified into low-molecular-weight organic EL device 10 and polymer-type organic EL device 10 in the technical field to which the present invention pertaining to organic EL device 10 belongs. Of these, the organic materials used in the low-molecular-weight organic EL element 10 are shown. In addition, low-molecular-weight organic materials are organic materials that do not fall under the macromolecules and polymer molecules defined by the International Union of Pure and Applied Chemistry (IUPAC) Polymer Nomenclature Committee.

Further, in the organic EL element 10 of the present embodiment, the thickness of the doped hole injection layer 42 and the hole transport layer 44 are made larger than those used in the conventional low-molecular-weight organic EL element 10, so that the total thickness of the organic functional layer 40 is The film thickness is adjusted to be larger than the film thickness of the thin metal wires 24 . As a result, the distance between the thin metal wire 24 and the opposing cathode 60 can be increased to obtain the organic EL element 10 with no electrical short and low leakage current.

The thin metal wires 24 of this embodiment have a convex structure with respect to the transparent substrate 22 . The film thickness t _TCE (FIG. 2) of the fine metal wire 24 in this specification is the length of the thickness direction of the fine metal wire 24 (normal direction to the surface of the transparent base material 22) in the cross section perpendicular to the extending direction of the fine metal wire 24. Specifically, it refers to the thickness (height of the protrusion) from the interface of the metal fine wires 24 on the transparent substrate 22 side to the metal fine wire 24 surface. When the fine metal wires 24 are provided on the surface of the transparent base material 22 in contact with the surface of the transparent base material 22 , the film thickness of the fine metal wires 24 is the thickness of the transparent base material 22 and the upper end surface of the fine metal wire 24 . When the fine metal wires 24 are provided on the surface of the transparent conductive inorganic compound layer in contact with the surface of the transparent conductive inorganic compound layer provided in contact with the surface of the transparent substrate 22, the thickness of the fine metal wires 24 is It corresponds to the distance between the surface of the transparent conductive inorganic compound layer and the upper end surface of the metal fine wire 24 in a cross section perpendicular to the extending direction of the metal fine wire 24 .

In this embodiment, t _TCE is 50 nm or more and 250 nm or less. _tTCE is preferably 60 nm or more and 200 nm or less, more preferably 65 nm or more and 180 nm or less, and even more preferably 70 nm or more and 165 nm or less.

When t _TCE is 50 nm or more, the resistance of the metal grid transparent electrode 20 can be reduced, and the organic EL element 10 tends to have a large area. In addition, there is a tendency that an increase in electrical resistance due to oxidation, corrosion, etc., of the surface of the fine metal wire 24 can be sufficiently suppressed.

On the other hand, since t _TCE is 250 nm or less, the thickness of the organic functional layer 40 can be adjusted within a range in which the thickness of the organic functional layer 40 is adjusted such that the luminance and power efficiency of the organic EL element 10 are not lowered. can sufficiently coat the fine metal wires 24 of In addition, there is a tendency for high transparency to be exhibited over a wide viewing angle.

t _TCE can be measured by observing the cross section of the metal grid transparent electrode 20 or the organic EL element 10 with an electron microscope (SEM, TEM, STEM) or by observing the plane of the metal grid transparent electrode 20 with a confocal laser microscope or the like. t _TCE can also be confirmed by measuring the film thickness profile of the metal grid transparent electrode 20 using a stylus-type thin film profilometer.

In this embodiment, when the thickness of the organic functional layer 40 on the metal fine wire 24 is t _org-TCE , (t _org-TCE −t _TCE ), that is, the thickness of the organic functional layer 40 and the thickness of the metal fine wire 24 is The film thickness difference is 50 nm or more and 750 nm or less. (t _org-TCE −t _TCE ) is preferably 60 nm or more and 500 nm or less, more preferably 70 nm or more and 400 nm or less, and even more preferably 80 nm or more and 300 nm or less.

When (t _org-TCE −t _TCE ) is 50 nm or more, the organic functional layer 40 can sufficiently cover the convex thin metal wires 24, and the distance from the opposing cathode 60 can be sufficiently secured. short circuit can be suppressed and leakage current can be sufficiently reduced.

On the other hand, since (t _org-TCE −t _TCE ) is 750 nm or less, the thickness of the organic functional layer 40 can be increased without excessively increasing the thickness of the organic functional layer 40 with respect to the thickness of the metal wire 24. It is possible to suppress deterioration in luminance and power efficiency of the organic EL element 10 due to the reduction of the organic EL element 10 . There are two reasons why the brightness and power efficiency of the organic EL element 10 are lowered by increasing the thickness of the organic functional layer 40 . First, the current density in the organic functional layer 40 follows the formula of space charge limited current (SCLC), and when the applied voltage is constant, the thickness of the organic functional layer 40 is increased to a power such as the cube. is inversely proportional to . Secondly, the thickening of the organic functional layer 40 reduces the visible light transmittance of each layer constituting the organic functional layer 40, making it difficult to extract light to the outside. Therefore, it is preferable to adjust the film thickness of the organic functional layer 40 within an appropriate range.

t _org-TCE is not particularly limited as long as (t _org-TCE −t _TCE ) can be adjusted within the above range, but is preferably 100 nm or more and 1000 nm or less, more preferably 120 nm or more and 700 nm or less, and still more preferably 135 nm or more and 550 nm or less. , particularly preferably 150 nm or more and 500 nm or less. With a t _org-TCE of 100 nm or more, even when a low-resistance metal grid transparent electrode 20 is used, the organic functional layer 40 can sufficiently cover the convex metal wires 24 , and furthermore, the opposing cathode 60 can be fully covered. Since sufficient distance can be secured, it tends to be possible to suppress electrical shorts and sufficiently reduce leakage current.

On the other hand, since the t _org-TCE is 1000 nm or less, it is possible to suppress deterioration in luminance and power efficiency of the organic EL element 10 due to thickening of the organic functional layer 40 .

t _org-TCE can be obtained from the total value of each layer constituting the organic functional layer 40 . For example, when forming each layer of the organic functional layer 40 by vapor deposition, the total thickness of each layer obtained from the vapor deposition rate (for example, Å/sec: vapor deposition film thickness per unit time) and the vapor deposition time (sec) can ask. Moreover, it can be confirmed by observing the cross section of the organic EL element 10 with an electron microscope (SEM, TEM, STEM). For example, regarding the cross-sectional SEM image of the organic EL element 10 shown in FIG. ), t _org-TCE can be confirmed by measuring the thickness of the film. Further, EDX (energy dispersive X-ray analysis) is performed on the observation field of the electron microscope image of the cross section of the organic EL element 10 to map the EDX intensity of the K shell of the carbon atom C, and the metal fine wire 24 and the cathode 60 The film thickness can be measured by using the region where the EDX intensity of the carbon atoms C between is the organic functional layer 40 . According to the manufacturing method shown in this embodiment as shown in FIG. The organic functional layer 40 provided on the transparent substrate 22 in the regions between the metal fine wires 24 has a second height from the surface of the transparent substrate 22 that is lower than the first height.

In addition, in the examples of Patent Documents 1 and 2, an inkjet is performed on a metal conductive layer obtained by electroplating silver or the like on a metal thin wire 24 having a line width of 5.8 μm to 50 μm formed by a printing method using silver nanoparticles. A metal grid transparent electrode 20 is disclosed in which a transparent conductive layer made of PSDOT:PSS is formed by a wet film forming method. On the other hand, the present inventors have adjusted the line width of the fine metal wire 24 containing the metal component M and the oxide of the metal component M to a fine range of 5 μm or less, or 3 μm or less for invisibility. . When a layer of PEDOT:PSS is wet-formed on such a fine metal wire 24, the metal oxide component of the metal wire 24 near the interface of the transparent substrate 22 is damaged by the PEDOT:PSS acidic aqueous coating liquid. It is presumed that the problem of underetching becoming more likely to occur and the fine metal wires 24 peeling off from the transparent base material 22 became apparent.

The organic EL element 10 of this embodiment uses a metal grid transparent electrode 20 as an anode. The organic functional layer 40 is a multi-layer body based on organic material having at least a doped hole injection layer 42 and a hole transport layer 44 provided between the anode and the cathode 60 . For the organic functional layer 40, the cathode 60, and the like, conventionally known materials and structures generally used for the organic EL element 10 can be applied.

Examples of the element configuration of the organic EL element 10 include the following various configurations.
(A) Anode/doped hole injection layer 42/hole transport layer 44/organic light emitting layer 46/cathode 60
(B) Anode/doped hole injection layer 42/hole transport layer 44/organic light emitting layer 46/electron transport layer 48/cathode 60
(C) Anode/doped hole injection layer 42/hole transport layer 44/organic light emitting layer 46/electron injection layer 50/cathode 60
(D) Anode/doped hole injection layer 42/hole transport layer 44/organic light emitting layer 46/electron transport layer 48/electron injection layer 50/cathode 60

The symbol "/" shown in (A) to (D) above indicates that the layers sandwiching the symbol "/" are laminated adjacent to each other. This also applies to the subsequent description. Also, the organic EL element 10 may be configured to have two or more organic light-emitting layers 46 .

t _org-TCE , which is the thickness of the organic functional layer 40, is the thickness of the doped hole injection layer 42, the thickness of the hole transport layer 44, and the thickness of the organic light emitting layer 46 in the case of the above configuration (A). corresponds to the sum.

In the case of the above configuration (B), t _org-TCE is the thickness of the doped hole injection layer 42, the thickness of the hole transport layer 44, the thickness of the organic light emitting layer 46, and the thickness of the electron transport layer 48. corresponds to the sum.

In the case of configuration (C) above, t _org-TCE corresponds to the sum of the thickness of the doped hole injection layer 42 , the thickness of the hole transport layer 44 and the thickness of the organic light emitting layer 46 . As will be described later, the electron injection layer 50 is usually made of an alkali metal or the like, and therefore is not included in the organic functional layer 40 in that case.

In the case of the above configuration (D), t _org-TCE is the thickness of the doped hole injection layer 42, the thickness of the hole transport layer 44, the thickness of the organic light emitting layer 46, and the thickness of the electron transport layer 48. corresponds to the sum. As will be described later, the electron injection layer 50 is usually made of an alkali metal or the like, and therefore is not included in the organic functional layer 40 in that case.

Further, the organic EL element 10 may include a transparent conductive inorganic compound layer, as described later. In that case, since the transparent conductive inorganic compound layer is not included in the organic functional layer 40, t _org-TCE does not include the film thickness of the transparent conductive inorganic compound layer.
[Metal grid transparent electrode 20]

The metal grid transparent electrode 20 of this embodiment has an electrode part consisting of a transparent base material 22 and a conductive pattern 24P composed of fine metal wires 24 provided on the transparent base material 22 .
[Transparent substrate 22]

A transparent substrate 22 is used in this embodiment. Here, the term “transparent” means that the visible light transmittance is preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more. Here, the visible light transmittance can be measured according to JIS K 7361-1:1997.

The transparent base material 22 may be made of one kind of material, or may be made of a laminate of two or more kinds of materials. Further, when the transparent base material 22 is a multilayer body in which two or more kinds of materials are laminated, the transparent base material 22 is formed by laminating transparent organic base materials or transparent inorganic base materials, which are listed as the core layer to be described later. It may also be one in which transparent organic substrates or transparent inorganic substrates are combined and laminated. In addition, the transparent substrate 22 can be appropriately provided with a barrier layer, an intermediate layer, or the like on a single layer or multilayer core layer. Examples of the form of the transparent substrate 22 include core layer, core layer/barrier layer, core layer/barrier layer/intermediate layer, core layer/intermediate layer/barrier layer, and the like. It is also possible to combine the barrier layer and the intermediate layer with one layer.
(core layer)

Materials constituting the core layer are not particularly limited, but those that contribute to the improvement of the mechanical strength of the substrate are preferable. Materials for such a core layer are not particularly limited, but examples include transparent inorganic substrates such as quartz glass, alkali-free glass, borosilicate glass, soda-lime glass, and lead glass; acrylic acid esters, methacrylic acid esters, polyethylene. Transparent materials such as terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polyvinyl chloride, polyethylene, polypropylene, polystyrene, nylon, aromatic polyamide, polyetheretherketone, polysulfone, polyethersulfone, polyimide, and polyetherimide An organic base material is mentioned. Among these, the use of polyethylene terephthalate is more excellent in productivity (cost reduction effect) for manufacturing the metal grid transparent electrode 20 . Moreover, by using polyimide, the heat resistance of the metal grid transparent electrode 20 is more excellent. When polyimide is used, it is more preferable to use so-called transparent polyimide, which has excellent optical transparency for visible light. Furthermore, the use of polyethylene terephthalate, polyethylene naphthalate, or alkali-free silica glass tends to further improve the adhesion between the transparent substrate 22 and the fine metal wires 24 .

The thickness of the core layer is preferably 5 μm or more and 2 mm or less, more preferably 10 μm or more and 1.5 mm or less.
(middle layer)

The intermediate layer can contribute to improving the adhesion between the transparent substrate 22 and the fine metal wires 24 or the adhesion between the core layer and the barrier layer. Further, in the manufacturing process of the metal grid transparent electrode 20 described later, when the metal components in the ink are sintered by a baking means such as plasma to form the core layer, portions of the core layer that are not covered with the fine metal wires 24 are formed by plasma or the like. and etching of the barrier layer can be prevented.

Components contained in the intermediate layer are not particularly limited. silicon oxide, silicon nitride, silicon chloride, silicate, zeolite, silicide, etc.), aluminum compounds (eg, aluminum oxide, etc.), magnesium compounds (eg, magnesium fluoride), and the like. Among these, silicon compounds are preferred, and siloxanes are more preferred. Examples of the silicon compound include, but are not limited to, condensates of polyfunctional organosilanes, polycondensates obtained by hydrolytically reacting polyfunctional organosilanes or oligomers thereof with polyvinyl acetate, and the like. . Examples of polyfunctional organosilanes include, but are not limited to, bifunctional organosilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane; trifunctional organosilanes such as trimethoxysilane, methyltriethoxysilane and phenyltrimethoxysilane; and tetrafunctional organosilanes such as tetramethoxysilane and tetraethoxysilane.

The intermediate layer can be formed by applying a composition containing the components contained in the intermediate layer to the core layer or the barrier layer, followed by drying. Also, the intermediate layer may be formed by a vapor deposition method such as PVD or CVD. The composition for forming the intermediate layer may contain dispersants, surfactants, binders and the like, if necessary.

The thickness of the intermediate layer is preferably 0.01 μm or more and 100 μm or less, more preferably 0.01 μm or more and 10 μm or less, and still more preferably 0.01 μm or more and 1 μm or less. When the film thickness of the intermediate layer is within the above range, the adhesion is further improved, and the transparency and durability of the metal grid transparent electrode 20 tend to be further improved.
(barrier layer)

The barrier layer is a layer having a high shielding performance against moisture and oxygen, and contributes to suppressing deterioration of the characteristics of the organic EL element 10 due to penetration of moisture and oxygen into the organic EL element 10 . As the gas barrier property of the barrier layer, the water vapor permeability (25 ± 0.5°C, relative humidity (90 ± 2)%) measured by a method conforming to JIS K 7129-1992 is 1 × 10 ^-7 g. /(m ² ·24 hr) to 1 x 10 ^-3 g/(m ² ·24 hr), preferably 1 x 10 ^-7 g/(m ² ·24 hr) to 1 x 10 ^-4 g/ It is more preferably in the range of (m ² ·24 hr), more preferably in the range of 1 × 10 ^-7 g/(m ² ·24 hr) to 1 × 10 ^-6 g/(m ² ·24 hr). . When the water vapor transmission rate is within this range, it is possible to suppress the occurrence of dark spots, which are non-light-emitting portions, in the organic EL element during long-term use, and to suppress deterioration of the characteristics of the organic EL element during long-term use. . Furthermore, the oxygen permeability measured by a method conforming to JIS K 7126-1987 is 1×10 ⁻⁶ mL/m ² ·24 h·atm to 1×10 ⁻² mL/m ² ·24 h·atm. 1×10 ⁻⁶ mL/m ² ·24 h·atm to 1×10 ⁻³ mL/m ² ·24 h·atm, more preferably 1×10 ⁻⁶ mL/m ² ·24 h·atm Atm to 1×10 ⁻⁴ mL/m ² ·24 h·atm is more preferable.

For the barrier layer, a conventionally known composition, structure, and formation method that are generally used in the organic EL element 10 can be applied. The barrier layer may be one layer, or may have a laminated structure of two or more layers. In the case of a laminated structure, even if the inorganic compound layer, the organic compound layer, or the inorganic polymer layer described later are laminated, the inorganic compound layer, the organic compound layer, or the inorganic polymer layer are laminated. may have been Among these, a structure in which inorganic compound layers and organic compound layers are alternately laminated a plurality of times is preferable in order to improve the fragility of the barrier layer.

_The inorganic compound layer of the barrier layer is not particularly limited _{. X} N _Y ), aluminum oxide (AlO _{x (0<X≤3/2)} ), aluminum nitride (AlN), and the like can be used. As a method for forming the inorganic compound layer, there are vapor phase film forming methods such as PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). For the purpose of forming a dense inorganic compound layer with few pinholes and high gas barrier properties, the inorganic compound layer is preferably formed by a sputtering method, PECVD, or ALD (Atomic Layer Deposition). The film thickness of the inorganic compound layer is preferably 30 nm or more and 1000 nm or less, more preferably 50 nm or more and 500 nm or less, and still more preferably 100 nm or more and 200 nm or less. When the film thickness of the inorganic compound layer is 30 nm or more, gas barrier properties are excellent. When the film thickness of the inorganic compound layer is 1000 nm or less, the visible light transmittance is excellent. In addition, it is possible to suppress the generation of cracks due to bending, and to prevent the generation of defects by suppressing the increase of internal stress during film formation.

The organic compound layer of the barrier layer is not particularly limited. Thermosetting resins such as resins, UV curable resins such as urethane acrylate, acrylic resin acrylate, epoxy acrylate, silicone acrylate, and UV curable epoxy resins, commercially available coating agents, and the like can be used. Further, the organic compound layer can also have a structure in which particles serving as a hygroscopic compound are dispersed in the layer. Hygroscopic compounds include, for example, metal oxides (such as sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (such as sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). , metal halides (e.g. calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (e.g. barium perchlorate, perchlorate Magnesium chlorate, etc.), etc., and anhydrous salts are preferably used for sulfates, metal halides and perchlorates. The organic compound layer can be formed, for example, by applying the coating liquid of the resin described above, drying it, and curing it by irradiating heat or ultraviolet rays. When the organic compound layer contains a hygroscopic material, the organic compound layer can be formed using a coating liquid in which the hygroscopic material is dispersed. The film thickness of the organic compound layer is preferably 0.5 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less, and still more preferably 10 μm or more and 30 μm or less. When the film thickness of the organic compound layer is 0.5 μm or more, gas barrier properties are excellent. When the film thickness of the organic compound layer is 100 μm or less, the visible light transmittance is excellent.

The inorganic polymer layer of the barrier layer is not particularly limited, but silicon-containing polymers such as polysilanes, polysilazanes, polysilthianes, polysiloxanes, and polysiloxazanes can be used. Among these, it is preferable to use polysiloxanes having Si--O bonds, polysilazanes having Si--N bonds, and polysiloxazanes containing both Si--O bonds and Si--N bonds. The inorganic polymer layer can be formed, for example, by applying a coating liquid containing a polysilazane compound, drying it, and then oxidizing it by irradiating ultraviolet rays in a nitrogen atmosphere containing oxygen and water vapor. The film thickness of the inorganic polymer layer is preferably 10 nm or more and 10 μm or less, more preferably 30 nm or more and 8 μm or less, and still more preferably 50 nm or more and 5 μm or less. When the film thickness of the organic compound layer is 10 nm or more, gas barrier properties are excellent. When the film thickness of the organic compound layer is 10 μm or less, the visible light transmittance is excellent.

It is particularly preferable to apply the same material and configuration as the thin film encapsulation layer 70 (TFE: Thin Film Encapsulation) disclosed in Non-Patent Document 3 as the barrier layer.
[Electrode part]

The electrode portion has a conductive pattern 24P composed of fine metal wires 24 arranged on the transparent base material 22 . Also, the fine metal wire 24 contains a metal component M and an oxide of the metal component M. As shown in FIG.

The metal component M is responsible for the electrical conductivity of the fine metal wire 24 . The mechanism by which the metal component M develops conductivity is not particularly limited, but is presumed to be similar to the free electron model of metals. Metal component M is not particularly limited, but examples thereof include gold, silver, copper, and aluminum. Among them, copper, which is relatively inexpensive and has high conductivity, is more preferable. By using such a metal component M, the conductivity of the metal grid transparent electrode 20 tends to be more excellent. The “metal grid” electrode includes an electrode in which a plurality of areas surrounded by metal wirings having vertices at intersections of the metal wirings are provided by providing a plurality of metal wirings extending in different directions. Here, each metal wiring may be extended linearly or curvedly. A region surrounded by metal wiring is called an opening, and a portion provided with the opening is sometimes called an opening. As will be described later, the plurality of metal wirings may be arranged periodically at a predetermined pitch, but they may also be arranged randomly in all or part of the area without being arranged regularly.

As disclosed in Patent Document 3, by including an oxide of the metal component M in the fine metal wires 24 , the refractive index of the fine metal wires 24 can be made close to the refractive index of the transparent substrate 22 . By bringing the refractive index of the metal fine wires 24 closer to the refractive index of the transparent substrate 22, reflection or scattering occurring at the refractive index interface between the metal fine wires 24 and the transparent substrate 22 is suppressed, and haze is reduced. Transparency can be further improved even when conductive patterns having the same width and aperture ratio are used. For example, if the metal component M is copper, the refractive index is 0.60 when the metal wires 24 are all made of copper, and the refractive index when the metal wires 24 are all made of copper oxide is 2.71. Therefore, if the fine metal wire 24 is composed of copper and copper oxide, it is considered that the refractive index is adjusted between them according to the composition ratio.

In addition, as similarly disclosed in Patent Document 3, by including an oxide of the metal component M in the metal fine wire 24, the transparent substrate 22 and the metal fine wire are improved in terms of mechanical properties such as bending, bending, and bending. 24 can be improved.

Furthermore, by including the oxide of the metal component M in the metal fine wire 24, the interface resistance at the time of hole injection from the metal component M to the doped hole injection layer 42 is reduced, the driving voltage of the organic EL element 10 is reduced, and the power efficiency can contribute to the improvement of The HOMO of organic materials generally used for the hole injection layer and the hole transport layer 44 is about 5.0 eV to 5.5 eV. On the other hand, for example, since the work function of copper is about 4.65 eV, an energy barrier of at least 0.35 eV or more is generated at the interface between copper and the doped hole injection layer 42 . This energy barrier causes an increase in interfacial resistance when holes are injected from the metal component M. On the other hand, by including cuprous oxide (valence band: about 5.25 eV) or cupric oxide (valence band: about 5.3 eV) in the contact interface between copper and the doped hole injection layer 42, By injecting holes from copper to the doped hole injection layer 42 via the valence band of copper oxide, the energy barrier can be reduced and the interfacial resistance can be reduced. In the literature (Xubing Lu et al., Effect of air exposure on metal/organic interface in organic field-effect transistors, Appl. Phys. Lett., June 2011, Vol. 98, P. 243301), oxidation from copper It is disclosed that interfacial resistance can be reduced by injecting holes through copper into an organic semiconductor having a HOMO of 5.0 eV as compared with direct hole injection from copper.

Although the oxide of the metal component M is not particularly limited, it is preferable to select copper as the metal component M for the reasons described above, so cuprous oxide, cupric oxide, copper hydroxide, and the like are preferable.

The maldistribution and uniformity of the oxide of the metal component M (that is, the oxygen atom O) within the cross section of the metal fine wire 24 is not particularly limited, and the oxide of the metal component M is approximately uniformly distributed in the cross section of the metal fine wire 24. It may be distributed, for example, it may be unevenly distributed at the interface of the metal fine wires 24 on the transparent substrate 22 side, or it may be unevenly distributed on the surface side of the metal fine wires 24 (the side opposite to the transparent substrate 22 side). may be Among these, from the two viewpoints of improving the transparency by making the refractive index of the metal fine wires 24 closer to the refractive index of the transparent substrate 22 and further improving the mechanical adhesion between the transparent substrate 22 and the metal fine wires 24. , the oxide of the metal component M is preferably unevenly distributed in the transparent base material 22 and tends to gradually decrease from the transparent base material 22 side toward the thickness direction of the fine metal wires 24 . Moreover, from the viewpoint of reducing interfacial resistance during hole injection into the doped hole injection layer 42 provided on the conductive pattern, the oxide of the metal component M is preferably present on the surface side of the fine metal wire 24 .

The maldistribution and uniformity of the metal component M in the metal fine wire 24 can be confirmed by the distribution of the atomic % ratio of oxygen atoms O to the metal component M by STEM-EDX analysis of the cross section of the metal fine wire 24 .

Thickness from 0.10t _TCE to 0.90t _TCE from the interface of the metal fine wire 24 on the transparent substrate 22 side in the STEM-EDX analysis of the cross section (FIG. 7) of the metal fine wire 24 perpendicular to the extending direction of the metal fine wire 24 The atomic % ratio O/M _0.10 to _0.90 of oxygen atoms O to the metal component M in the region is preferably 0.01 or more and 1.00 or less, more preferably 0.02 or more and 0.80 or less, and still more preferably 0 0.03 or more and 0.75 or less. When the atomic % ratio O/M _0.10 to _0.90 is 0.01 or more, the transparency is excellent and the mechanical adhesion between the transparent substrate 22 and the fine metal wires 24 tends to be improved for the reasons described above. In addition, there is a tendency that the energy barrier during hole injection can be reduced. On the other hand, when the atomic % ratio O/M _0.10 to _0.90 is 1.00 or less, the ratio of the oxide of the metal component M is decreased, so that the resistance tends to be lowered.

The atomic % ratio O/M _0.75 to _0.90 in the thickness region from the interface of the metal fine wires 24 on the transparent substrate 22 side to 0.75t _TCE to 0.90t _TCE is the oxygen atoms present in the region on the surface side of the metal fine wires 24 It is an index showing the ratio of O. Such atomic % ratio O/M _0.75 to _0.90 is preferably 0.25 or less, more preferably 0.22 or less, and still more preferably 0.18 or less. When the atomic % ratio O/M _0.75 to _0.90 is 0.25 or less, the resistance tends to be further reduced. The minimum value of the atomic % ratio O/M 0.75 to 0.90 is preferably greater than 0 for the purpose of reducing the energy barrier during hole injection.

In addition, the atomic % ratio O/M _0.10 to _0.25 in the thickness region from the interface of the metal fine wires 24 on the transparent substrate 22 side to 0.10t _TCE to 0.25t _TCE is the interface of the metal fine wires 24 on the transparent substrate 22 side. It is an index indicating the ratio of oxygen atoms O present in the region on the side of Such atomic % ratio O/M _0.10 to _0.25 is preferably 0.05 or more, more preferably 0.06 or more, and still more preferably 0.07 or more. When the atomic % ratio O/M _0.10 to _0.25 is 0.05 or more, the transparency tends to be excellent, and the mechanical adhesion between the transparent base material 22 and the fine metal wires 24 tends to be improved. Also, the atomic % ratio O/M _0.10 to _0.25 is preferably 1.10 or less, more preferably 1.00 or less, and still more preferably 0.95 or less. When the atomic % ratio O/M _0.10 to _0.25 is 1.10 or less, the resistance tends to be further reduced.

Therefore, for example, the metal fine wire 24 has an atomic % ratio O/M of a first value (for example, a value of 0.25 or less) at a first position at a first distance from the interface of the metal fine wire 24 on the transparent substrate 22 side. and the atomic % ratio O/M has a second value (for example, 0.05 or more and 1. 10 or less). Here, the first distance may be a value larger than (t _TCE /2) (eg, 0.75t _TCE to 0.90t _TCE ), and the second distance may be a value smaller than (t _TCE /2) (eg, 0 .10t _TCE to 0.25t _TCE ). Also, the second value may be two or more times greater than the first value.

The atomic % ratio O/M _0.10 to _0.90 , the atomic % ratio O/M _0.75 to _0.90 , and the atomic % ratio O/M _0.10 to _0.25 are obtained by STEM-EDX of the cross section of the metal fine wire 24 perpendicular to the extending direction of the metal fine wire 24. It can be obtained from analysis. Specifically, the thin metal wire 24 is cut in a direction orthogonal to the extending direction of the metal thin wire 24 to obtain a thin section exposing the cross section of the metal thin wire 24 as a measurement sample. At this time, if necessary, the thin section may be formed after embedding the metal grid transparent electrode 20 in a support such as epoxy resin. The method for forming the cross section of the metal fine wire 24 is not particularly limited as long as it is a method that can suppress damage to the cross section of the metal fine wire 24 due to the formation and processing of the cross section. Ion Beam) processing method, FIB (Focused Ion Beam) processing method), precision mechanical polishing, ultramicrotome, and the like can be used.

Next, the measurement sample obtained as described above is observed with a scanning transmission electron microscope (STEM) to obtain an STEM image of the cross section of the fine metal wire 24 . At the same time, elemental mapping of the cross section of the metal wire 24 is performed by energy dispersive X-ray analysis (EDX). Specifically, the EDX intensity of the K shell of the oxygen atom O and the EDX intensity of the K shell of the metal component M are measured for each section of the cross section. This operation is performed on at least a thickness region of 0.10t _TCE to 0.90t _TCE from the interface of the metal thin wire 24 on the side of the transparent substrate 22 in the cross section of the metal thin wire 24. The integrated value of the EDX intensity of the shell and the integrated value of the EDX intensity of the K shell of the metal component M are calculated, and the ratio of these integrated values is obtained as the atomic % ratio O/M _0.10 to _0.90 . As for the atomic % ratio O/M _0.75 to _0.90 and the atomic % ratio O/M _0.10 to _0.25 , the ratio of the integrated values is obtained by the same method in the target thickness range.

Note that t _TCE can be the maximum thickness from the interface of the metal fine wire 24 on the transparent substrate 22 side to the metal fine wire 24 surface within the measurement field of view of the STEM image of the cross section of the metal fine wire 24 . From the viewpoint of preventing oxidation and contamination of the cross section of the metal fine wire 24, the formation of the cross section of the metal fine wire 24 and the STEM-EDX analysis are preferably performed in an inert atmosphere such as argon or in a vacuum.

Each value of the atomic % ratio O/M _0.10 to _0.90 , the atomic % ratio O/M _0.75 to _0.90 , and the atomic % ratio O/M _0.10 to _0.25 is not particularly limited, but the firing conditions for forming the metal fine wire 24 are determined. By adjusting, the increase or decrease can be controlled. For example, when firing a desired pattern formed using an ink containing an oxide of the metal component M, by adjusting the degree of participation or reduction of the oxide of the metal component M depending on the firing conditions, atoms in the metal fine wire 24 The % ratio O/M can be adjusted.

In addition, the thin metal wire 24 can contain a non-conductive component in addition to the metal component M responsible for conductivity. The non-conductive component is not particularly limited, and examples thereof include oxides of the metal component M and organic compounds. More specifically, these non-conductive components are components derived from the components contained in the ink, which will be described later, and among the components contained in the ink, the metal component M that remains in the fine metal wires 24 after firing. oxides and organic compounds of

The content of the metal component M in the fine metal wire 24 is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. Although the upper limit of the content of the metal component M is not particularly limited, it is less than 100% by mass. Also, the content of the non-conductive component in the fine metal wires 24 is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. Although the lower limit of the content of the non-conductive component is not particularly limited, it exceeds 0% by mass.
(Conductive pattern)

The conductive pattern 24P may be a regular pattern or an irregular pattern. For example, mesh patterns 24P1 to 24P3 (FIG. 4) formed by a plurality of thin metal wires 24 extending linearly and intersecting each other in a mesh pattern, or mesh patterns 24P1 to 24P3 (FIG. 4) in which hexagonal openings are provided without gaps. A honeycomb pattern 24P4 (FIG. 5) in which thin metal wires 24 are provided in portions corresponding to sides, and a line pattern 24P5 (FIG. 6) in which a plurality of substantially parallel thin metal wires 24 are formed. Also, the conductive pattern 24P may be an arbitrary combination of the mesh patterns 24P1 to 24P3, the honeycomb pattern 24P4, and the line pattern 24P5. Further, the conductive pattern 24P may be provided such that polygonal openings other than rectangular and hexagonal openings are formed without gaps. For example, when the thin metal wires 24 defining polygonal openings define adjacent polygonal openings at the same time, a plurality of polygonal openings are formed without gaps. The conductive pattern 24P may be configured to have openings of different polygonal shapes. The meshes of the mesh patterns 24P1 to 24P3 may be squares ((A) in the figure) or rectangles ((B) in the figure) as shown in FIG. 4, or diamonds ((C) in the figure). good too. The honeycomb pattern 24P4 may be provided in a regular hexagonal shape so as to have a constant line width as shown in FIG. may be provided so as to be rounded. Further, the thin metal wires 24 forming the line pattern 24P5 may be straight lines as shown in FIG. 6 or may be curved lines. Further, part or all of the fine metal wires 24 forming the mesh patterns 24P1 to 24P3 and the honeycomb pattern 24P4 may be curved.
(line width)

The line width W _TCE of the metal fine wire 24 is the line width W _TCE when the metal fine wire 24 is projected onto the surface of the transparent substrate 22 from the side of the transparent substrate 22 on which the conductive pattern 24P is arranged. As shown in FIG. 7, in the metal thin wire 24 having a trapezoidal cross section with a long base on the interface side with the transparent substrate 22, the width of the surface of the conductive thin wire in contact with the transparent substrate 22 is the line width W Become _{a TCE} .

W _TCE is preferably 0.25 μm or more and 5.0 μm or less, more preferably 0.25 μm or more and 4.0 μm or less, still more preferably 0.25 μm or more and 3.0 μm or less, and even more preferably 0.25 μm or more2 0 μm or less, particularly preferably 0.25 μm or more and 1.0 μm or less. When W _TCE is 0.25 μm or more, the resistance of the metal grid transparent electrode 20 can be reduced, and the organic EL element 10 tends to have a larger area. In addition, it is possible to sufficiently suppress an increase in electrical resistance due to oxidation, corrosion, etc. of the surface of the fine metal wire 24 . On the other hand, since the line width W _TCE of the metal thin wire 24 is 5.0 μm or less, the spatial luminance distribution in the opening of the conductive pattern is made uniform, so that a high aperture ratio can be maintained even when the gap is made small. , the luminance of the organic EL tends to be improved. Furthermore, by adjusting the line width W _TCE of the metal thin wire 24 to 3.0 μm or less, the opaque metal thin wire 24 can be made invisible to the human eye, and the appearance and design of the organic EL element 10 can be improved.
(gap)

The gap G _TCE of the conductive pattern 24P in this specification is the shortest of the distances (intervals) between the adjacent thin metal wires 24 extending in the same direction in the conductive pattern 24P and facing substantially perpendicular to the extending direction ( (However, when the thin metal wire 24 extends in a curved shape, the gap G _TCE is the distance between two adjacent metal wires in which straight lines approximating the curve are generally in the same direction at least within a predetermined area.) corresponding to the minimum distance between thin lines 24).

FIG. 12 is a graph showing simulation results for different line widths W _TCE with the horizontal axis representing the gap G _TCE of the conductive pattern 24P and the vertical axis representing the luminance value obtained by the simulation. As shown in the figure, the upper limit of G _TCE is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm, even more preferably 20 μm or less, and even more preferably 15 μm. or less, and particularly preferably 12 μm or less. In addition, G _TCE /W _TCE is preferably 1.0 or more, more preferably 1.5, still more preferably 2.0, even more preferably 2.5 or more, and even more preferably 3.0. Above all, 3.5 is particularly preferable. When G _TCE /W _TCE is 1.0 or more, the aperture ratio can be improved, and the luminance of the organic EL tends to be improved. On the other hand, when the G _TCE is 50 μm or less, the spatial luminance distribution in the openings of the conductive pattern tends to become uniform, so the luminance and power efficiency of the entire organic EL element 10 tend to improve. The inventors of the present application conjecture the reason why the brightness of the entire organic EL element 10 is improved by reducing the gap as follows. Holes injected from the metal wire 24 by applying an external voltage diffuse in-plane into the opening of the conductive pattern through the doped hole injection layer 42 . By reducing the gap and shortening the hole diffusion distance from the thin metal wire 24 to the center of the opening, the voltage drop due to the surface resistance of the doped hole injection layer 42 due to the in-plane diffusion of holes can be reduced. By uniformizing the voltage at the openings of the conductive pattern, the spatial luminance distribution can be uniformized. Since the luminance is a value obtained by dividing the in-plane integrated value of the spatial luminance distribution by the integrated area, it is considered that the luminance of the entire organic EL element 10 can be improved by making the spatial luminance distribution uniform.
(Aperture ratio)

The aperture ratio _ATCE of the conductive pattern is preferably 35% or more and less than 100%, more preferably 40% or more and 99% or less, still more preferably 50% or more and 98% or less, and even more preferably 55%. % or more and 97% or less, more preferably 60% or more and 96% or less, and particularly preferably 62% or more and 95% or less. An aperture ratio _ATCE of 35% or more tends to improve the luminance of the organic EL. When the aperture ratio A _TCE is less than 100%, the occupancy rate of the fine metal wires 24 per unit area is increased, so the sheet resistance is reduced, and the organic EL element 10 tends to have a larger area.

The “aperture ratio” of the conductive pattern can be calculated by the following formula for the area where the conductive pattern is formed on the transparent base material 22 .

Aperture ratio=(1-area occupied by conductive pattern/area of transparent substrate 22 in region where conductive pattern is formed)×100

For example, in the case where the conductive pattern 24P is a mesh pattern 24P1 having square openings as shown in FIG. area) is 36%, and the area of the opening through which the transparent substrate 22 is exposed is 64%, so the opening ratio is 64%.

FIG. 12 is a graph showing simulation results for different line widths W _TCE with the horizontal axis representing the product of the gap G _TCE and the aperture ratio A _TCE of the conductive pattern 24P and the vertical axis representing the brightness value obtained by the simulation. . (G _TCE · A _TCE ) is the reduction of the hole diffusion distance (G _TCE ) in the in-plane direction in the opening of the conductive pattern, which makes the spatial luminance distribution uniform, and the increase in the aperture ratio (A _TCE ). The increase in the extraction amount to the organic EL element 10 is expressed as an indicator that the luminance of the organic EL element 10 is improved. For example, with the same line width, if the gap is reduced, the diffusion length of holes is reduced, and the spatial luminance distribution of the opening is made uniform, thereby improving the luminance. On the other hand, as the aperture ratio decreases, the shadowing effect of the opaque thin metal wires 24 increases, making it difficult to extract light to the outside. Therefore, the inventors of the present application focused on the fact that the brightness of the organic EL element 10 provided with the metal grid transparent electrode 20 can be improved by adjusting (G _TCE · _ATCE ) to a suitable range. As shown in the figure, (G _TCE · _ATCE ) is preferably 0.6 μm·% or more and 30 μm·% or less, more preferably 1.0 μm·% or more and 20 μm·% or less, and even more preferably is 1.2 μm.% or more and 17 μm.% or less, more preferably 1.5 μm.% or more and 15 μm.% or less, and particularly preferably 2.0 μm.% or more and 12.0 μm.% or less. When (G _TCE · A _TCE ) is 0.6 μm·% or more, the brightness of the organic EL element 10 is improved by uniformizing the spatial brightness distribution in the opening while suppressing the decrease in brightness due to the light shielding effect of the thin metal wire 24 . can improve. On the other hand, when (G _TCE ·A _TCE ) is 30 µm·% or less, it is possible to improve the brightness of the organic EL element 10 by increasing the aperture ratio while suppressing the decrease in brightness at the opening.
(Cross-sectional shape)

The cross-sectional shape of the fine metal wire 24 is not necessarily a flat surface, and often has an uneven surface. shape, substantially semi-elliptical shape, and the like. The term "substantially trapezoidal" here means that the legs of the trapezoid may be straight lines (sides) or curved lines, and the legs of the trapezoid may be curved lines. means that it may be outwardly convex or inwardly convex. In addition, in the "substantially trapezoidal shape", the one corresponding to the upper base may be a straight line (side) or may have unevenness. The cross-sectional shape of such a thin metal wire 24 can be defined by the line width W _TCE and the film thickness t _TCE . Based on the film thickness t _TCE of the metal fine wire 24, the height from the interface between the transparent substrate 22 and the conductive fine wire is defined as 0.50t _TCE and 0.90t _TCE (FIG. 7). The width of the metal wire 24 at a height of 0.50t _TCE is W _0.50 , and the width of the metal wire 24 at a height of 0.90t _TCE is W _0.90 . At this time, W _0.50 /W _TCE is preferably 0.70 or more and less than 1.00, more preferably 0.75 or more and 0.99 or less, and still more preferably 0.80 or more and 0.95 or less. . again. W _0.90 /W _0.50 is preferably 0.50 or more and 0.95 or less, more preferably 0.55 or more and 0.90 or less, and still more preferably 0.60 or more and 0.85 or less. Also, W _0.50 /W _TCE is preferably greater than W _0.90 /W _0.50 . That is, it is preferable that the width of the metal fine wire 24 gradually decreases from the height position at the thickness of 0.50t _TCE to the height position at the thickness of 0.90t _TCE from the interface of the metal fine wire 24 on the transparent substrate 22 side. . As a result, the edge of the cross section of the metal fine wire 24 is reduced, and the thickness uniformity of the organic functional layer 40 attached to the metal fine wire 24 is further improved. There is a tendency that the leakage current of the EL element 10 can be reduced.

As will be described later, the metal grid transparent electrode 20 of this embodiment can be formed by a printing method using ink, and the thin metal wires 24 formed by this method have the characteristic shape as described above.

The line width of the metal thin wire 24 and the gap and aperture ratio of the conductive pattern 24P can be confirmed by observing the surface or cross section of the metal grid transparent electrode 20 with an electron microscope, a laser microscope, an optical microscope, or the like. Methods for adjusting the line width of the metal thin wire 24 and the gap between the conductive pattern 24P to a desired range include a method of adjusting the grooves of a plate used in the method of manufacturing the metal grid transparent electrode 20 described later, and a method of adjusting metal particles in the ink. A method of adjusting the average particle size and the like can be mentioned.
(sheet resistance)

The sheet resistance R _{s_TCE} of the conductive pattern 24P of the metal grid transparent electrode 20 is preferably 0.1Ω/sq. 100Ω/sq. It is below. The upper limit of the sheet resistance is more preferably 50Ω/sq. or less, more preferably 40Ω/sq. or less, and more preferably 35Ω/sq. or less, and particularly preferably 25Ω/sq. It is below. When the sheet resistance is 100 Ω/sq or less, it is possible to suppress the decrease in luminance of the organic EL element 10 due to the voltage drop caused by the electrical resistance of the metal grid transparent electrode 20, and the organic EL element 10 tends to have a large area. Sheet resistance is determined by reducing the aperture ratio of the conductive pattern 24P, increasing the film thickness of the fine metal wire 24, increasing the content of the metal component M in the fine metal wire 24, and selecting a metal component M with high conductivity. It can be reduced by making adjustments such as

Sheet resistance can be measured by a four-probe method based on JIS K 7194:1994 for the portion where the conductive pattern 24P is arranged. Examples of the four-terminal method measuring instrument include "Loresta GP" (product name, manufactured by Mitsubishi Chemical Corporation). The sheet resistance can also be measured by a non-contact method using an eddy current conforming to ASTM F 673-02 on the portion where the conductive pattern 24P is arranged.
(visible light transmittance)

The visible light transmittance T _VLT of the region where the conductive pattern 24P of the metal grid transparent electrode 20 is arranged is preferably 30% or more and 98% or less, more preferably 36% or more and 96% or less. more preferably 45% or more and 94% or less, still more preferably 49% or more and 92% or less, still more preferably 54% or more and 91% or less, and particularly preferably 55% or more and 90% or less be. The visible light transmittance tends to be improved by increasing the aperture ratio of the conductive pattern 24P. The visible light transmittance can be calculated from the transmission spectrum of the area where the conductive pattern 24P of the metal grid transparent electrode 20 is arranged in accordance with JIS R 3106:2019 or ISO9050:2003. It can also be calculated by multiplying the visible light transmittance of the transparent substrate 22 by the aperture ratio of the conductive pattern 24P.
[Transparent conductive inorganic compound layer]

In the metal grid transparent electrode 20 of this embodiment, a transparent conductive inorganic compound layer can be provided on the conductive pattern 24P. Also, the transparent conductive inorganic compound layer can be arranged between the transparent substrate 22 and the conductive pattern 24P. By providing the transparent conductive inorganic compound layer on the metal grid transparent electrode 20, the holes are diffused from the metal wiring through the transparent conductive inorganic compound layer to the opening of the conductive pattern 24P. It can be made more uniform. When the transparent conductive inorganic compound layer is provided on the conductive pattern 24P, the doped hole injection layer 42 is provided on the transparent conductive inorganic compound layer.

The transparent conductive inorganic compound layer is preferably formed by a vapor deposition method such as PVD or CVD for the purpose of not exposing the metal wiring to the acidic aqueous solution as described above. In particular, it is preferable to form the film by a sputtering method or a vacuum deposition method.

The material used for the transparent conductive inorganic compound layer is not particularly limited as long as it has a high transmittance in the visible _light region and is an _inorganic compound that exhibits conductivity. SnO ₂ series, ZnO series such as AZO and GZO _, (ZnO-In ₂ O ₃ ) series such as Zn _{2 In 2} O ₅ and Zn _{3 In 2} O ₂ , (In ₂ O ₃ —SnO ₂ ) system, and (ZnO—SnO ₂ ) system such as Zn ₂ SnO ₄ and ZnSnO ₃ . Other known materials used for transparent conductive oxides can be used. Among these, it is preferable to use ITO (indium tin oxide), which is most widely used and has excellent transparency and conductivity.

The film thickness of the transparent conductive inorganic compound layer is preferably 10 nm or more and 1000 nm or less, more preferably 10 nm or more and 500 nm or less, still more preferably 10 nm or more and 300 nm or less, and particularly preferably 10 nm or more and 200 nm or less. When the film thickness of the transparent conductive inorganic compound layer is 10 nm or more, the sheet resistance of the transparent conductive inorganic compound layer can be reduced, and the opening of the conductive pattern 24P through the transparent conductive inorganic compound layer. Diffusion of holes is facilitated, and the spatial luminance distribution of the opening tends to be more uniform. On the other hand, when the film thickness of the transparent conductive inorganic compound layer is 1000 nm or less, it tends to be possible to suppress the decrease in luminance of the organic EL element 10 due to the decrease in the visible light transmittance of the transparent conductive inorganic compound layer. In particular, when the film thickness of the transparent conductive inorganic compound is in the range of 10 nm or more and 30 nm or less, the transmittance of the transparent conductive inorganic compound increases and the light emission characteristics of the organic EL element itself improve, which is particularly preferable.

The upper limit of the sheet resistance of the transparent conductive inorganic compound layer is preferably 500Ω/sq. Below, more preferably 200Ω/sq. Below, more preferably 100Ω/sq. Below, particularly preferably 50Ω/sq. It is below. The sheet resistance of the transparent conductive inorganic compound layer is 500Ω/sq. When the ratio is below, the diffusion of holes into the opening of the conductive pattern 24P through the transparent conductive inorganic compound layer is further promoted, and the spatial luminance distribution of the opening tends to be more uniform. The lower limit of the sheet resistance of the transparent conductive inorganic compound layer is not particularly limited, and is, for example, 0.1Ω/sq. can be mentioned.

The lower limit of the visible light transmittance of the transparent conductive inorganic compound layer is preferably 60% or higher, more preferably 70% or higher, still more preferably 80% or higher, and particularly preferably 90% or higher. When the visible light transmittance of the transparent conductive inorganic compound layer is 60% or more, the brightness of the organic EL element 10 tends to be improved. The upper limit of the visible light transmittance of the transparent conductive inorganic compound layer is not particularly limited, and may be, for example, 100% or less.
[Manufacturing Method of Metal Grid Transparent Electrode 20]

The method for manufacturing the metal grid transparent electrode 20 includes a pattern forming step of forming a pattern on the transparent base material 22 using an ink containing a metal component M, a conductive pattern by baking the ink, and a conductive pattern, which will be described later if necessary. and a baking step of forming the second conductive pattern 26P that becomes the current collecting portion.
[Pattern formation process]

A pattern formation process is a process of forming a pattern using the ink containing the metal component M. FIG. The pattern forming step is not particularly limited as long as it is a plate printing method using a plate having grooves of a desired conductive pattern. a step of transferring the ink on the surface of the transfer medium to the surface of the convex portion of the letterpress by pressing and contacting the surface of the convex portion of the letterpress so as to face the surface of the convex portion of the letterpress; are opposed to each other and pressed and brought into contact with each other to transfer the ink remaining on the surface of the transfer medium to the surface of the transparent base material 22 . When an intermediate layer or a barrier layer is formed on the transparent substrate 22, the ink is transferred to the surface of the outermost layer on the transfer side. Further, when a transparent conductive inorganic compound layer is provided on the transparent substrate 22, the ink is transferred onto the transparent conductive inorganic compound layer.
(ink)

The ink used in the pattern forming step contains a metal component M and a solvent, and may contain a surfactant, a dispersant, a reducing agent, etc., if necessary. The metal component M may be contained in the ink as metal particles, or may be contained in the ink as a metal complex.

The average primary particle size of the metal particles is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. Although the lower limit of the average primary particle size of the metal particles is not particularly limited, it may be 1 nm or more. By setting the average primary particle diameter of the metal particles to 100 nm or less, the line width of the fine metal wires 24 to be obtained can be made thinner. The “average primary particle size” refers to the particle size of each metal particle (so-called primary particle), and is the particle size of an aggregate (so-called secondary particle) formed by gathering a plurality of metal particles. It is distinguished from a certain average secondary particle size.

The metal particles are not particularly limited, but for example, a metal oxide or metal compound containing a metal component M such as copper oxide as a constituent atom, a core part of which is a metal component M such as copper, and a shell part of which is copper oxide. and core/shell particles that are metal oxides containing a metal component M as constituent atoms. The aspect of the metal particles can be appropriately determined from the viewpoint of dispersibility and sinterability.

The content of the metal particles in the ink is preferably 1% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and still more preferably It is 5% by mass or more and 35% by mass or less, more preferably 10% by mass or more and 35% by mass or less.

The surfactant is not particularly limited, and examples thereof include fluorine-based surfactants. The use of such a surfactant tends to improve the coating properties of the ink on the transfer medium (blanket) and the smoothness of the coated ink, resulting in a more uniform coating film. In addition, it is preferable that the surfactant be capable of dispersing the metal component M and not likely to remain during firing.

The content of the surfactant in the ink is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, relative to the total mass of the ink composition. more preferably 0.5% by mass or more and 2% by mass or less.

The dispersant is not particularly limited, but includes, for example, a dispersant that non-covalently bonds or interacts with the surface of the metal component M, and a dispersant that covalently bonds with the surface of the metal component M. Non-covalently bonding or interacting functional groups include dispersants having phosphate groups. By using such a dispersant, the dispersibility of the metal component M tends to be further improved.

The content of the dispersant in the ink is preferably 0.1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 20% by mass or less, based on the total mass of the ink composition. It is preferably 2% by mass or more and 10% by mass or less.

Furthermore, examples of solvents include alcohol solvents such as monoalcohols and polyhydric alcohols; alkyl ether solvents; hydrocarbon solvents; ketone solvents; These may be used alone or in combination of one or more. For example, a combination of a monoalcohol having 10 or less carbon atoms and a polyhydric alcohol having 10 or less carbon atoms can be used. By using such a solvent, the ability to coat the transfer medium (blanket) with the ink, the ability to transfer the ink from the transfer medium to the letterpress, the ability to transfer the ink from the transfer medium to the transparent substrate 22, and the metal component Dispersibility of M tends to be further improved. In addition, it is preferable that the solvent be capable of dispersing the metal component M and not easily remain during firing.

The content of the solvent in the ink is the balance of the components such as the metal particles, the surfactant, and the dispersant described above, and is preferably 50% by mass or more and 99% by mass, for example, based on the total mass of the ink composition. or less, more preferably 60% by mass or more and 90% by mass or less, and still more preferably 70% by mass or more and 80% by mass or less.
[Baking process]

In the baking step, for example, the metal component M in the ink transferred to the surface of the transparent base material 22 is sintered to form the conductive pattern 24P and, if necessary, the second conductive pattern 26P serving as the current collector. do. The firing is not particularly limited as long as it is a method that allows the metal component M to fuse and form a metal component sintered film. Firing may be performed, for example, in a firing furnace, or may be performed using plasma, a heated catalyst, ultraviolet rays, vacuum ultraviolet rays, electron beams, infrared lamp annealing, flash lamp annealing, laser, or the like. When the sintered film to be obtained is easily oxidized, firing in a non-oxidizing atmosphere is preferred. Moreover, when the metal oxide or the like is difficult to be reduced only by the reducing agent that may be contained in the ink, it is preferable to perform the firing in a reducing atmosphere.

A non-oxidizing atmosphere is an atmosphere that does not contain an oxidizing gas such as oxygen, and includes an inert atmosphere and a reducing atmosphere. An inert atmosphere is, for example, an atmosphere filled with an inert gas such as argon, helium, neon, or nitrogen. A reducing atmosphere refers to an atmosphere in which a reducing gas such as hydrogen or carbon monoxide is present. The ink coating film (dispersion coating film) may be fired in a closed system by filling these gases into a firing furnace. Alternatively, the dispersion coating film may be baked while these gases are flowed by using a baking furnace as a flow system. When the dispersion-coated film is to be fired in a non-oxidizing atmosphere, it is preferable to first evacuate the firing furnace to remove oxygen in the firing furnace and replace the oxygen with a non-oxidizing gas. Also, the firing may be performed in a pressurized atmosphere or in a reduced pressure atmosphere.

The firing temperature is not particularly limited, but is preferably from 20°C to 400°C, more preferably from 50°C to 300°C, and even more preferably from 80°C to 200°C. A firing temperature of 400° C. or less is preferable because a substrate with low heat resistance can be used. Moreover, when the firing temperature is 20° C. or higher, the formation of the metal component sintered film proceeds sufficiently, and the electrical conductivity tends to be improved, which is preferable. The resulting sintered metal component film contains a conductive component derived from the metal component M, and may contain a non-conductive component depending on the components used in the ink and the firing temperature.

For the purpose of promoting fusion bonding of the metal component M and obtaining a metal component sintered film having higher conductivity, it is more preferable to use a firing method using plasma. From the same point of view, the plasma output is preferably 0.5 kW or more, more preferably 0.6 kW or more, and still more preferably 0.7 kW or more. The upper limit of the plasma output is not particularly limited as long as it does not damage the transparent substrate 22 and the intermediate layer used. The lower limit of the firing time depends on the plasma output, but from the viewpoint of productivity, the upper limit is preferably 1000 sec or less, more preferably 600 sec or less. In addition, you may bake by using plasma baking several times as needed.
[Current collector]

The organic EL element 10 of the present embodiment can include a current collector provided on the transparent substrate 22 and electrically connected to the conductive pattern 24P. The organic EL element 10 is an element that controls light emission by voltage/current applied from an external circuit. For this reason, the current collector is connected to a terminal from the external circuit and has a function of propagating the voltage/current signal applied from the external circuit to the conductive pattern 24P. FIG. 3 schematically shows the positional relationship between the conductive pattern 24P provided on the transparent substrate 22 and the second conductive pattern 26P electrically connected to the conductive pattern 24P and functioning as a current collector. is a top view. However, the specific shapes of the conductive pattern 24P and the second conductive pattern 26P are omitted in FIG.

The current collector is not particularly limited as long as it can be electrically connected to the conductive pattern 24P, and conventionally known materials and structures generally used for the organic EL element 10 can be applied. Materials used for the current collector include metals such as gold, silver, copper, aluminum and molybdenum, metal laminates such as molybdenum/aluminum/molybdenum, and metal alloys thereof.

Further, the organic EL element 10 of the present embodiment includes a current collector (bus bar) having a second conductive pattern 26P formed on the transparent substrate 22 and electrically connected to the conductive pattern 24P. can be provided. The second conductive pattern 26P may use the same constituent material, structure, and design adjustment range as the conductive pattern 24P of the [metal grid transparent electrode 20]. For the purpose of simplifying the manufacturing process, the second conductive pattern 26P is preferably formed together with the conductive pattern 24P by the above-described [Manufacturing Method of Metal Grid Transparent Electrode 20]. In addition, from the viewpoint of suppressing deterioration in light emission uniformity of the organic EL element 10 due to voltage drop in the current collector, the above-described metal, metal laminate, or metal alloy is further deposited on the second conductive pattern 26P by a vacuum deposition method or the like. It can also be laminated by a sputtering method or the like.
(Occupied area ratio)

The occupied area ratio S _Bus of the second conductive pattern 26P is preferably 50% or more and less than 100%. The lower limit of S _Bus is more preferably 60% or more, and still more preferably 70% or more. When the occupied area ratio S _Bus of the second conductive pattern 26P is within the above range, the electrical connection with the external terminal is further improved, the resistance of the current collector can be reduced, and the voltage drop of the applied voltage can be reduced. tend to be suppressed.

The "occupied area ratio" of the conductive pattern can be calculated by the following formula for the area on the transparent substrate 22 where the conductive pattern is formed.

Occupied area ratio=(Area occupied by the conductive pattern/Area of the transparent substrate 22 in the region where the conductive pattern is formed)×100

For example, when the second conductive pattern 26P is the square mesh pattern shown in FIG. 4A, the line width is 2 μm and the gap is 2 μm. occupied area) is 75%, the occupied area ratio S _Bus is 75%. Similarly, if the line width is 5 μm and the gap is 12 μm, the occupied area ratio S _Bus is 50%.
(line width, gap)

The line width W _Bus of the fine metal wires 24 forming the second conductive pattern 26P is preferably 0.25 μm or more and 10 μm or less, more preferably 0.5 μm or more and 8 μm or less, and still more preferably 1 μm or more and 5 μm or less. When W _Bus is within the above range, the connectability with the external terminal is further improved, the sheet resistance of the current collecting portion can be reduced, and the voltage drop of the applied voltage tends to be suppressed. The gap G _Bus of the second conductive pattern 26P can be appropriately set according to the conductive pattern and W _Bus so that the occupied area ratio S _Bus is within the above range.
[Organic functional layer 40]
[Doped hole injection layer 42]

The organic EL device 10 of this embodiment has a doped hole injection layer 42 made of a low-molecular-weight organic material in the organic functional layer 40 . A doped hole injection layer 42 is provided on the conductive pattern 24P of the metal grid transparent electrode 20 . Since the doped hole injection layer 42 of the present embodiment can be formed by a vapor deposition method, it can be suitably applied to the metal grid transparent electrode 20 having the fine metal wires 24 containing an oxide of the metal component M such as copper oxide having low acid resistance. Further, the doped hole injection layer 42 suppresses electrical shorts in the organic EL element 10 by increasing the film thickness, reduces leakage current, diffuses holes injected from the fine metal wires 24 into the openings of the conductive pattern 24P, It has the function of injecting holes into the hole transport layer 44 .

When the doped hole injection layer 42 is provided on the conductive pattern 24P in contact with the upper surfaces of the metal wires 24 as shown in the enlarged view of the region A in FIG. The layer 42 is the interface of the metal fine wires 24 on the transparent substrate 22 side (the surface of the transparent substrate 22, or the conductive inorganic compound layer provided on the surface of the transparent substrate 22 and the metal fine wires 24 on the conductive inorganic compound layer). is provided, it approaches the surface of the conductive inorganic compound layer) and contacts the surface including the metal fine wire 24 interface on the transparent substrate 22 side. Therefore, it becomes possible to cover the thin metal wires 24 . In addition, when the conductive inorganic compound layer is provided on the conductive pattern 24P in contact with the upper surface of the metal fine wires 24, the conductive inorganic compound layer in the region between the adjacent metal fine wires 24 is the metal layer on the transparent substrate 22 side. The surface including the interface of the fine wire 24 is approached to contact the surface including the interface of the metal fine wire 24 on the side of the transparent substrate 22 .

The doped hole injection layer 42 is composed of at least one low-molecular-weight host material and at least one low-molecular-weight dopant, and conventionally known materials and structures generally used in the organic EL device 10 can be used. can.
(Low-molecular-weight host material)

The low-molecular-weight host material is preferably a material used for the hole transport layer 44 or a material having a HOMO level close to that of the hole transport layer 44 from the viewpoint of reducing the energy barrier in hole injection into the hole transport layer 44 . The low-molecular-weight host material is not particularly limited, but for example, (1) BF-DPB (N,N'-[(Diphenyl-N,N'-bis)9,9,-dimethyl-fluoren-2-yl] -benzidine), (2) MeO-TPD (N,N,N',N'-tetrakis (4-methylphenyl)-benzidine), (3) Spiro-TTB (2,2',7,7'-tetrakis ( N,N'-di-p-methylphenylamino)-9,9'-spirobifluorene), (4) NPB (N,N'-di(naphtalene-1-yl)-N,N'-diphenylbenzidine), (5) PV-TPD (N,N'-di(4-(2,2-diphenyl-ethen-1-yl)-phenyl)-N,N'-di(4-methylphenylphenyl) benzidine), (6) ZnPc (zinc -phthalocyanine), (7) TDATA, (8) m-MTDATA, (9) TPD, (10) CuPc, (11) HAT, (12) F ₁₆ CuPc, (13) 1-TNATA (4,4′, 4″-Tris (N-(1-naphthyl)-N-phenylamino) triphenylamine), (14) 2-TNATA (4,4′,4″-Tris[2-naphthyl(phenyl)amino]triphenylamine), (15) NPNPB (N,N'-diphenyl-N,N'-di-[4-(N,N-diphenyl-amino)phenyl]benzidine), (16) DNTPD (N1,N1'-(Biphenyl-4 ,4′-diyl)bis(N1-phenyl-N4,N4-di-m-tolylbenzene-1,4-diamine), (17) HAT-CN(1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile) , (18) PPDN (Pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile), etc. (The structure and materials of the organic EL element including each organic functional layer are, for example, , Caroline Murawski et al., Alternative p-doped hole transport material for low operating voltage and high efficiency organic light-emitting diodes, Applied Physics Letters, September 2014, Vol. 105, P. 113303, S. Olthof et al. , Journal of Applied Physics, Photoelectron spectroscopy study of systematically varied doping concentrations in an organic semiconductor layer using a molecular p-dopant, October 2009, Vol. 106, P. 103711, M Pfeiffer et al., Doped organic semiconductors: Physics and application in light emitting diodes, Organic Electronics, Sep. 2003, Vol. 4, P. 89-103, Seiji Tokito, Organic EL Display, Aug. 2004, Ohmsha, P. 101-120, 114-119, 217-219, 224-269, etc., it can be understood by those skilled in the art.
Furthermore, as described below, the structure and materials of organic EL elements are also described on the Internet, and therefore can be understood by those skilled in the art (materials, etc. are listed below without exemplifying specific literature names, etc.).
"Hole Injection Layer (HIL) Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat2-lang1.html>,
"Hole Transport Layer (HTL) Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat15-lang1.html>,
"Fluorescent Host Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat3-lang1.html>,
"Phosphorescent Host Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat4-lang1.html>,
"Hole Blocking / Electron Transporting Layer Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat16-lang1.html>,
"Blue Dopant Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat17-lang1.html>,
"Green Dopant Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat18-lang1.html>,
"Red Dopant Materials", [online], Shine Materials Technology Co., Ltd., [searched on September 6, 2021], Internet
<URL: https://www.shinematerials.com/goods1-cat19-lang1.html>
(low-molecular-weight dopant)

The low-molecular-weight dopant is not particularly limited as long as it is a material that imparts electrical conductivity to the doped hole injection layer 42 and improves hole diffusion in the layer. (2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile), (2) F4-TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), (3) F2 -TCNQ (3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane), (4) TCNQ (tetracynoquinodimethane), (5) NDP-2 (manufactured by Novaled), (6) NDP-9 (manufactured by Novaled), (7) ortho-chloranil, (8) DDQ (dicyano-dichloroquinone), (9) TPT9, (10) BSB-Cz, etc. (references and the like are the same as above).

The doped hole injection layer 42 may thus comprise, for example, BF-DPB doped with F6-TCNNQ.
(dopant density)

The dopant density N _p in this specification refers to the content equivalent volume (vol %) occupied by the low-molecular-weight dopant contained in the doped hole injection layer 42 with respect to the total area of the doped hole injection layer 42 . By increasing or decreasing the dopant density, the electrical conductivity (and sheet resistance) of the doped hole injection layer 42 and the absorption coefficient (and visible light transmittance) in the visible light region can be adjusted within preferred ranges. _Np is preferably 3 vol% or more and 18 vol% or less, more preferably 4 vol% or more and 15 vol% or less, and still more preferably 5 vol% or more and 10 vol% or less. When N _p is 3 vol % or more, the electrical conductivity of the doped hole injection layer 42 tends to be improved. On the other hand, when N _p is 18 vol % or less, the absorption of visible light by the dopant is suppressed and the visible light transmittance tends to be improved.

In the co-evaporation process of a low-molecular-weight host material and a low-molecular-weight dopant, N _p is determined by adjusting the deposition rate of each material (for example, Å/sec: deposited film thickness per unit time) and the deposition time (sec). You can control it. For example, based on the previously obtained calibration curves of the deposition rates of the low-molecular-weight host material and the low-molecular-weight dopant, the deposition rate of the low-molecular-weight host material is set to 0.9 × α (Å / sec), and the low-molecular-weight dopant N _p can be 10 vol % by adjusting the vapor deposition rate of to 0.1×α (Å/sec). Any numerical value can be used for α.
(film thickness)

The film thickness t _HIL of the doped hole injection layer 42 is preferably 30 nm or more and 200 nm or less, more preferably 40 nm or more and 150 nm or less, still more preferably 50 nm or more and 100 nm or less. When t _HIL is 30 nm or more, there is a tendency that electrical shorts can be suppressed and leak current can be reduced by increasing the thickness of the organic functional layer 40 . In addition, since the sheet resistance of the doped hole injection layer 42 can be reduced, holes injected from the thin metal wire 24 can easily diffuse through the doped hole injection layer 42 into the opening of the conductive pattern 24P. This tends to make the spatial luminance distribution in the opening uniform. On the other hand, when t _HIL is 200 nm or less, the visible light transmittance of the doped hole injection layer 42 tends to be improved, so that the light emitted from the organic light emitting layer 46 can be easily extracted to the outside. Also, it is possible to suppress a decrease in current density due to an increase in the thickness of the organic functional layer 40 .

t _HIL can be controlled by adjusting the deposition rate and deposition time of each material in the co-evaporation process of the low-molecular-weight host material and low-molecular-weight dopant. Also, as _tHIL , a numerical value calculated from vapor deposition process conditions can be used.
(Electrical conductivity)

The lower limit of the electrical conductivity σ _HIL of the doped hole injection layer 42 is preferably 5×10 ⁻⁵ S/cm or more, more preferably 7×10 ⁻⁵ S/cm or more, and still more preferably 8×10 ⁻⁵ S/cm. / cm or more. Although σ _HIL increases as the dopant density increases, it tends to saturate when the dopant density exceeds a certain level (for example, 10 vol %). 4,4′,4″-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), which is a representative example of a hole injection layer made of a low-molecular-weight organic material, has an electric conductivity of about 10 ^{−10 .} S/cm. The doped hole injection layer 42 of the present embodiment has electrical conductivity five orders of magnitude higher than that of a general hole injection layer made of a conventional low-molecular-weight organic material due to the addition of a low-molecular-weight dopant. When σ _HIL is 5×10 ⁻⁵ S/cm or more, the sheet resistance of the doped hole injection layer 42 can be reduced. It becomes easier to diffuse into the opening of 24P. This tends to make the spatial luminance distribution in the opening uniform. Although the upper limit of σ _HIL is not particularly limited, it can be, for example, 3.0×10 ⁻⁴ S/cm or less. Thereby, it is possible to suppress the decrease in the visible light transmittance of the doped hole injection layer 42 due to the increase in the dopant density.
σ _HIL is the sheet resistance of the thin film of the doped hole injection layer 42 measured by a four-terminal method conforming to JIS K 7194:1994 or a non-contact method using eddy current conforming to ASTM F 673-02. can be calculated from the film thickness t _HIL of the doped hole injection layer 42 used for . σ _HIL can also be measured by the following method. First, a measurement sample is prepared by forming a doped hole injection layer 42 on comb-shaped electrodes formed on a glass substrate. For the measurement sample, the electrical resistance R at both ends of the comb-shaped electrode is measured. Using the film thickness t _HIL of the doped hole injection layer 42, the channel length L _CH and the total channel width W _CH of the comb-shaped electrodes, σ _HIL (S/cm) can be calculated by the following equation.

σ _HIL =L _CH /(R×t _HIL ×W _CH )
(sheet resistance)

The sheet resistance of the doped hole injection layer 42 can be calculated from the electrical conductivity and film thickness of the doped hole injection layer 42 . The upper limit of the sheet resistance of the doped hole injection layer 42 is preferably 6.5×10 ⁹ Ω/sq. Below, more preferably 4.5×10 ⁹ Ω/sq. Below, more preferably 3.0×10 ⁹ Ω/sq. Below, particularly preferably 2.5×10 ⁹ Ω/sq. It is below. The sheet resistance of the doped hole injection layer 42 is 6.5×10 ⁹ Ω/sq. Since the holes injected from the metal thin wire 24 are easily diffused into the opening of the conductive pattern 24P through the doped hole injection layer 42, the spatial luminance distribution in the opening tends to be made uniform. . Although the lower limit of the sheet resistance of the doped hole injection layer 42 is not particularly limited, it is, for example, 1.5×10 ⁸ Ω/sq. The above can be mentioned. As a result, it is possible to suppress a decrease in the visible light transmittance of the doped hole injection layer 42 due to an increase in the film thickness of the doped hole injection layer 42 and an increase in the dopant density. tend to become
(visible light transmittance)

The visible light transmittance of the doped hole injection layer 42 tends to be increased by decreasing the dopant density or decreasing the film thickness of the doped hole injection layer 42 . The visible light transmittance of the doped hole injection layer 42 is preferably 80% or more and 100% or less, more preferably 82% or more and 97% or less, and still more preferably 84% or more and 95% or less. When the visible light transmittance of the doped hole injection layer 42 is 80% or more, the light emitted from the organic light emitting layer 46 tends to be easily extracted to the outside.

The visible light transmittance of the doped hole injection layer 42 can be confirmed by the following method. A measurement sample is prepared by forming a doped hole injection layer 42 on a glass substrate. The optical absorption spectrum of the doped hole injection layer 42 with the effect of the glass substrate removed is measured by UV-vis spectroscopy using the glass substrate as the measurement sample and the reference sample. A transmission spectrum is calculated from the acquired light absorption spectrum. Visible light transmittance can be calculated from the transmission spectrum of the doped hole injection layer 42 according to JIS R 3106:2019 or ISO9050:2003.
[Hole transport layer 44]

The organic EL device 10 of this embodiment has a hole transport layer 44 made of a low-molecular-weight organic material in the organic functional layer 40 . A hole transport layer 44 is provided on the doped hole injection layer 42 by vapor deposition. The hole transport layer 44 of the present embodiment suppresses electrical shorts in the organic EL element 10 by increasing the film thickness, reduces leakage current, and transports holes injected from the doped hole injection layer 42 to the organic light emitting layer 46 and the like. It has the function of However, the hole transport layer 44 and the doped hole injection layer 42 may be composed of the same material.

The hole transport layer 44 is made of a material used as a low-molecular-weight host material for the doped hole-injection layer 42 or a low-molecular-weight host material for the doped hole-injection layer 42 from the viewpoint of reducing an energy barrier in hole injection from the doped hole-injection layer 42 . It is preferably formed of a material having a HOMO level close to that of the host material. Similarly, from the viewpoint of reducing the energy barrier in hole injection from the hole transport layer 44 to the organic light emitting layer 46, it is preferably formed of a material having a HOMO level close to that of the organic light emitting layer 46. From this point of view, the hole transport layer 44 may be made of one kind of material, or by laminating two or more kinds of materials, the HOMO of the hole transport layer 44 may be similar to that of the doped hole injection layer 42 . A configuration in which the level is changed stepwise from the level to the level close to the organic light-emitting layer 46 may be employed. The material used for the hole transport layer 44 is not particularly limited as long as it is a low-molecular-weight organic material, and conventionally known materials generally used for the organic EL device 10 can be used. Materials used for the hole transport layer 44 include, in addition to the materials described above for the doped hole injection layer 42, (1) Spiro-TAD (2,2′,7,7′-Tetrakis (N, N-diphenylamino)-9,9′-spirobifluorene), (2) VNPB (N4,N4′-Di(naphthalen-1-yl)-N4,N4′-bis(4-vinylphenyl)biphenyl-4,4′- diamine), (3) Tris-PCz (9-Phenyl-3,6-bis(9-phenyl-9Hcarbazol-3-yl)-9H-carbazole), (4) TAPC (1,1-Bis[(di- 4-tolylamino)phenyl]cyclohexane), (5) BF-DPB (N4,N4'-Bis(9,9-dimethyl-9H-fluoren-2-yl)-N4,N4'-diphenylbiphenyl-4,4'- diamine), (6) α-NPD (N,N'-Di-1-naphthyl-N,N'-diphenylbenzidine), (7) (DTP) DPPD, (8) HTM1, (9) TPTE1, (10) TCTA (tris(4-carbazoyl-9-ylphenyl)amine), (11) NTPA, (12) TFLFL, (13) TPTR, (14) TPTE, (15) TPPE, etc. as well).

The film thickness t _HTL of the hole transport layer 44 is preferably 30 nm or more and 200 nm or less, more preferably 50 nm or more and 180 nm or less, still more preferably 80 nm or more and 170 nm or less, and particularly preferably 100 nm or more and 160 nm or less. When the hole transport layer 44 has a structure in which two or more materials are laminated, t _HTL is the total film thickness of the hole transport layer 44 .

t _HTL can be controlled by adjusting the deposition rate and deposition time of the material used for the hole transport layer 44 in the deposition process. Also, t _HTL can use a numerical value calculated from the vapor deposition process conditions.
[Organic light-emitting layer 46]

For the organic light-emitting layer 46, conventionally known materials generally used for the organic EL element 10 can be used. Examples of host materials used in the organic light-emitting layer 46 for fluorescence emission due to radiative transition from an excited singlet state include (1) Alq ₃ (Tris (8-quinolinolato) aluminum (purified by sublimation)), ( 2) TBADN (2-tert-Butyl-9,10-di(naphth-2-yl)anthracene), (3) TPB3 (1,3,5-Tri(pyren-1-yl)benzene), (4) ADN (9,10-Bis(2-naphthyl)anthracene), (5) MADN (2-methyl-9,10-bis(naphthalen-2-yl)anthracene), (6) Alq, (7) Almq, ( 8) Mgq, (9) _BeBq2 , (10) ZnPBO, (11) ZnPBT, (12) Be(5Fla) ₂ , (13) BpVBi, (14) Eu complex, (15) APD, (16) BSB, (17) BAlq (Bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum), (18) azomethine metal complex, (19) distyrylbenzene derivative, (20) DTVBi derivative, (21) DSB derivative etc. As a material that serves both as the electron transport layer 48 and the organic light emitting layer 46, both the electron transport layer 48 and the organic light emitting layer 46 may be made of _Alq3 (the same applies to the cited documents, etc.).

The organic light-emitting layer 46 includes perylene, DPT, PMDFB, quinacridone, rubrene, BTX, ABTX, DCM, DCJT, DCJTB, DCJMTB, TDPF, PtOEP, Btp ₂ Ir (acac), coumarin derivative (C540) as a guest material. , distyryl compounds (BCzVBi), ADN, TBP, FIrpic, FIr6, europium complexes (Eu(TTA) ₃ phen) (as above for references etc.).

For example, it is known that the organic light emitting layer 46 can improve the efficiency of blue light emission by combining ADN having an anthracene skeleton and a perylene derivative TBP. For the organic light-emitting layer 46, for example, a dimer of anthracene as a host material may be doped with 1% C545T as a guest material to improve the efficiency of green light emission. Also, the organic light-emitting layer 46 may obtain red light emission by doping _Alq3 as a host material with DCM1 or DCM2 as a guest material.

Further, the organic light-emitting layer 46 may contain a phosphorescent material for emitting phosphorescence due to radiation transition from an excited triplet state in addition to fluorescence due to radiation transition from an excited singlet state. Materials include, for example, (1) CBP (4,4′-Bis(N-carbazolyl)-1,1′-biphenyl), (2) TCTA, (3) UGH-2 (1,4-Bis(triphenylsilyl ) benzene), (4) 26DCzPPy (2,6-bis(3-(carbazol-9-yl)phenyl)pyridine), (5) DPDT (2,8-Bis(diphenyl-phosphoryl)-dibenzo[b,d ]thiophene), (6) DPEPO (Bis[2-(diphenylphosphino)phenyl]ether oxide), (7) mCPSOB (9-(3-(9H-Carbazol-9-yl)-5-(phenylsulfonyl)phenyl)- 9H-carbazole), (8) DCzDCN (5-(4,6-Diphenyl-1,3,5-triazin-2-yl)benzene-1,3-dinitrile), (9) Spiro-2CBP (2,7 -Bis(carbazol-9-yl)-9,9-spirobifluorene), (10) mCP (1,3-Bis(N-carbazolyl)benzene), (11) TCP (1,3,5-tris(carbazol- 9-yl) benzene), (12) CzSi (1,3,5-tris(carbazol-9-yl) benzene), (13) BCBP (2,2′-bis(4-(carbazol-9-yl) phenyl)-biphenyl), (14) BCPO (Bis-4-(N-carbazolyl) phenyl) phenylphosphine oxide), (15) DCzDBT (2,8-Di(9-carbazolyl) dibenzothiophene), (16) mCBP (3 , 3-Di(9H-carbazol-9-yl)biphenyl), (17) CPCB (3-(3-(9H-Carbazol-9-yl)phenyl)-9-(3-(3-(3-( 9H-carbazol-9-yl)phenyl)-9Hcarbazo-9-yl)phenyl)-9H-carbazole), (18) Spiro-CBP (2,2′,7,7′-Tetrakis(carbazol-9-yl) -9,9-spirobifluoren). In addition, Btp ₂ Ir(acac), iridium complex Ir(ppy) ₃ , carbazole derivative CBP, FIrpic, Fir6, Ir(thpy) ₃ , Ir(t5m-thpy) ₃ , Ir(t-5CF ₃ -py) ₃ , Ir(t-5t-py) ₃ , Ir(mt-5mt-py) ₃ , Ir(btpy) ₃ , Ir(tflpy) ₃ , Ir(piq) ₃ , Ir(tiq) ₃ , Ir(fliq) ₃ , ppy, tpy, bzq, thp, оp, bо, bt, bon, αbsn, btp, ppо, C6, pq, β-bsn, ppz, Ir(Fppy) ₃ , Ir(Fppy) ₂ (acac), or Ir (ppy) ₂ (acac) (same as above for cited references, etc.).

A rare earth complex can be used as the organic light-emitting layer 46 in addition to the above-described fluorescent light-emitting materials centered on organic low-molecular-weight compounds and phosphorescent light-emitting materials such as platinum and iridium complexes. The rare earth complex is composed of ions of rare earth elements (atomic numbers 58 to 71, lanthanum (La), scandium (Sc), yttrium (Y)) and organic ligands. Specifically, the organic light-emitting layer 46 may include a Tb(III) complex Tb(acac) ₃ , an Eu(III) complex. For example, organic light-emitting layer 46 may be composed of poly(methylphenylsilane) (PMPS) doped with an Eu(III) complex. Also, the organic light emitting layer 46 may be composed of CBP or the like doped with Eu(dbm) ₃ (Tmphen), Eu(dbm) ₃ (phen), or Tb(dbm) ₃ (phen). The organic light emitting layer 46 may comprise Eu _x Tb _1-x (acac) ₃ (phen). Furthermore, DCJTB and FIrpic may be doped as assist dopants.

Note that the organic light-emitting layer 46 may be configured to emit light using the thermal activation delay tendency. That is, by reducing the energy difference between the excited singlet state and the excited triplet state, or by thermal energy, the reverse energy transition from the excited triplet state to the excited singlet state is caused with high efficiency, resulting in thermal activation. It becomes possible to express delayed fluorescence (TDFM). Specifically, the organic light-emitting layer 46 may be composed of PVCz (host material) doped with, for example, 2% by weight SnF ₂ (OEP) (guest material). Alternatively, the organic light-emitting layer 46 may be composed of 1,3-bis(9-carbazolyl)benzene (mCP) doped with 6% by weight of PIC-TRZ.

Note that the organic light-emitting layer 46 may include a plurality of light-emitting layers that emit different colors. By stacking a plurality of light-emitting layers that emit different colors, it is possible to adjust the finally emitted color. For example, the organic light-emitting layer 46 may comprise a blue-emitting TPD layer and a green- and red-emitting Nile-Red doped _Alq3 layer stacked on the TPD layer via an adjustment layer. Such a configuration enables the organic light-emitting layer 46 to emit white light.
[Electron transport layer 48]

For the electron transport layer 48, conventionally known materials generally used in the organic EL element 10 can be used. Materials used for the electron transport layer 48 include, for example, (1) Alq ₃ , (2) Bphen (4,7-Diphenyl-1,10-phenanthroline), (3) TPBi (2,2′,2′). '-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzomidazole)), (4) TAZ (3-(4-Biphenyl)-4-phenyl-5-tert-butylphenyl-1 ,2,4-triazole), (5) TmPyPB (1,3,5-Tris(3-pyridyl-3-phenyl)benzene), (6) BeBq2 (1,3,5-Tris(3-pyridyl-3 -phenyl)benzene), (7) TSPO1 (iphenyl[4-(triphenylsilyl)phenyl]phosphine oxide), (8) T2T (2,4,6-tris(biphenyl-3-yl)-1,3,5- triazine), (9) BAlq (Bis (2-methyl-8-quino; -Biphenyl-4-olato) aluminum), (10) BCP (Bis (2-methyl-8-quino; -Biphenyl-4-olato) aluminum), (11) Liq (8-Hydroxyquinolinolato-lithium), (12) NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), (13) Be(PP)2(Bis[2-(2-hydroxyphenyl)-pyridine]beryllium), (14) B3PyPB(1,3-Bis[3,5-di(pyridin-3-yl)phenyl]benzene), ( 15) 3TPYMB (Tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane), (16) DPPS (Diphenyl-bis(4-(pyridin-3-yl)phenyl)silane) etc. Furthermore, oxadiazole derivative (tBu-PBD), oxadiazole dimer (OXD-7), starburst oxadiazole, TRAZ, phenylquinoxaline derivative (TPQ), silole derivative (PyPySPyPy), CBP, benzimidazole derivative (TPBI), pyrimidine derivatives (B3PymPm), or BpyOXD. Further, the material of the electron transport layer 48 may contain a boron derivative (BMB-nT) or a phosphine oxide derivative (POPy ₂ ) in order to introduce a typical element other than carbon and nitrogen (similar to the above references, etc.). ).
[Electron injection layer 50]

The electron injection layer 50 can use conventionally known materials generally used in the organic EL element 10 . Materials used for the electron injection layer 50 include, for example, materials with _a small work function and high activity such as LiF, _Li2O3 , Ca, Ba, Cs, and LiF/Ca.
[Cathode 60]

The cathode 60 can use conventionally known materials generally used for the organic EL element 10 . Materials used for the cathode 60 include, for example, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, metals such as terbium, ytterbium, and alloys of two or more thereof; or one or more thereof together with gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin alloys with one or more; graphite or graphite intercalation compounds; These 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. For example, the cathode 60 may be composed of an alloy of MgAg, MgIn, or AlLi (as above for references etc.).
[Thin film sealing layer 70]

The thin-film encapsulating layer 70 is a layer having high shielding performance against moisture and oxygen, like the barrier layer described above. The provision of the thin-film encapsulating layer 70 contributes to suppressing deterioration in the characteristics of the organic EL element 10 due to penetration of moisture and oxygen into the organic EL element 10 . The thin-film encapsulating layer 70 is provided on the cathode 60, and can be formed so as to cover the organic EL element 10 other than a partial region of the current collecting portion exposed for connection with an external terminal. The thin-film encapsulating layer 70 can employ a conventionally known composition, structure, and formation method that are commonly used in the organic EL device 10, and preferably have the same composition and structure as the barrier layer described above. . As the thin film encapsulation layer 70, it is particularly preferable to apply the thin film encapsulation layer 70 (TFE) disclosed in Non-Patent Document 3.

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.
<<Reference example S1>>

The suitability of the metal grid transparent electrode composed of fine metal wires containing copper and copper oxide to the PEDOT:PSS film forming process will be specifically described below.
<<Manufacturing of Metal Grid Transparent Electrode>>
[Preparation of transparent substrate S]
A polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name: Cosmoshine A4100, film thickness 50 μm) with an easy-adhesion layer formed on one side is used as a core layer, and the one side on which the easy-adhesion layer is not formed is used. 2% by mass of silicon oxide nanoparticles, 1% by mass of a conductive organic silane compound, 65% by mass of 2-propanol, 25% by mass of 1-butanol, and 7% by mass of water. After drying, a transparent substrate S having a 150 nm-thick intermediate layer containing silicon oxide was obtained.
[Ink 1]

20 parts by mass of cuprous oxide nanoparticles with a particle size of 21 nm, 4 parts by mass of a dispersant (manufactured by Big Chemie, product name: Disperbyk-145), and a surfactant (manufactured by Seimi Chemical Co., product name: S-611). 1 part by mass and 75 parts by mass of ethanol were mixed and dispersed to prepare Ink 1 containing 20% by mass of cuprous oxide nanoparticles.
[Manufacture of metal grid transparent electrode S]

First, the ink 1 is applied to the surface of the transfer medium, and then the surface of the transfer medium coated with the ink and the plate having the grooves of the conductive pattern are opposed to each other, pressed, and brought into contact with each other so that the convex surface of the plate is applied to the surface of the transfer medium. part of the ink was transferred. After that, the surface of the transfer medium coated with the remaining ink and the transparent base material S are opposed to each other, pressed and brought into contact with each other, and the desired conductive patterned ink 1 is transferred onto the intermediate layer of the transparent base material S. rice field. Next, the conductive patterned ink coating film (dispersion coating film) on the transparent substrate is irradiated with plasma of 0.9 kW for 180 seconds in a reducing atmosphere to remove cuprous oxide in the dispersion coating film. was reduced to copper, and a mesh pattern metal grid transparent electrode S was obtained by a firing process for forming a sintered film of the metal component of copper.
<<Evaluation of metal grid transparent electrode>>
[Measurement of line width, gap and film thickness]

For the obtained metal grid transparent electrode S, the line width W _TCE and film thickness t _TCE of the metal thin line, and the gap G _TCE of the conductive pattern 24P were calculated from a planar photograph taken with a confocal laser microscope. The metal grid transparent electrode S had a W _TCE of 1.1 μm, a t _TCE of 153 nm, and a G _TCE of 98.5 μm.
[STEM-EDX analysis of metal fine wire cross section]

Using a focused ion beam (FIB), the metal grid transparent electrode S thus obtained was cut into slices having a thickness of 200 nm or less, including the cross section of the fine metal wire perpendicular to the extending direction of the fine metal wire. The obtained thin section was attached to the tip of a silicon sample stage, and STEM-EDX measurement was performed as a measurement sample under the following conditions.

STEM: Scanning transmission electron microscope HD-2300A manufactured by Hitachi High-Technologies Corporation
EDX: Energy dispersive X-ray spectrometer manufactured by EDAX, GENESIS
Accelerating voltage: 200 kV
Measurement magnification: 25,000 times Electron beam incident angle: 90°
X-ray extraction angle: 18°
Mapping elements: Cu, O
Accumulation times: 200 dwell time: 200 μsec.
Resolution: 256 x 200 pixels

Next, the measurement sample obtained as described above was observed with an STEM to obtain an STEM image of the cross section of the fine metal wire. At the same time, elemental mapping of the cross section of the metal wire was performed by energy dispersive X-ray analysis (EDX). Specifically, the EDX intensity of the K-shell of the oxygen atom O and the EDX intensity of the K-shell of the copper atom Cu were measured at each cross-sectional location, and this operation was performed for the entire cross-section of the metal thin wire.

On the other hand, from the STEM image, the maximum thickness t _TCE from the metal fine wire interface on the transparent _substrate side to the metal fine wire in the measurement field is calculated. Calculate the integrated value of the EDX intensity of the K shell of the oxygen atom O and the integrated value of the EDX intensity of the K shell of the copper atom in the thickness region up to _TCE , and the ratio of these integrated values is the atomic % ratio O / Cu _0.10 ~ obtained as _0.90 . Similarly, for the thickness regions from 0.10t _TCE to 0.25t _TCE and 0.75T to 0.90T from the metal fine wire interface on the transparent substrate side, the atomic % ratio O/Cu _0.10-0.25 was obtained by the same method. and the atomic % ratio O/Cu _0.75-0.90 were calculated. It is believed that the oxygen atoms O are primarily derived from copper oxide (cuprous oxide, cupric oxide, and/or copper hydroxide). Therefore, the atomic % ratio O/Cu _0.10 to _0.25 indicates uneven distribution of copper oxide on the interface side with the transparent substrate, and the atomic % ratio O/Cu _0.75-0.90 indicates the uneven distribution of copper oxide on the surface side. Table 1 shows the results.

From Table 1, it can be seen that relatively many oxygen atoms O (that is, copper oxide) in the fine metal wires of the metal grid transparent electrode S are present near the interface on the transparent substrate side. This is presumably because the reduction of cuprous oxide in plasma firing proceeds from the surface of the fine metal wire, and a large amount of unreduced cuprous oxide such as cuprous oxide remains near the interface of the transparent substrate.
[PEDOT: compatibility test for PSS film formation process]
Next, a water-based coating solution of PEDOT:PSS (product name: Clevios PVP AI 4083, pH 1.5 to 2.5) was spin-coated on the metal grid transparent electrode prepared in the same manner as the metal grid transparent electrode S, and PEDOT:PSS was applied. A hole injection layer consisting of was formed. The sheet resistance of the metal grid transparent electrode S before PEDOT:PSS film formation is 330Ω/sq. However, the sheet resistance after film formation was unmeasurable (Range Over), and it was confirmed that the fine metal wires were separated from the transparent substrate S. This is because the copper oxide existing near the interface of the transparent substrate dissolved in the organic sulfonic acid derived from PSS in the water-based coating liquid, and the fine metal wires were under-etched, and the fine metal wires were peeled off from the transparent substrate. Infer. From this result, it can be seen that PEDOT:PSS cannot be wet film-formed on a metal grid transparent electrode provided with fine metal wires containing copper and copper oxide.
<<Example A>>

Hereinafter, an organic EL device using a metal grid transparent electrode provided with fine metal wires containing copper and copper oxide will be specifically described.
[Example A1]
<<Manufacturing of Metal Grid Transparent Electrode>>
[Preparation of transparent substrate A]

Alkali-free glass (manufactured by Corning, product name: EAGLE XG, thickness 1.1 mm) was used as the transparent substrate A.
[Production of Metal Grid Transparent Electrode A1]

First, the ink 1 is applied to the surface of the transfer medium, then the surface of the transfer medium to which the ink is applied and the plate having the grooves of the conductive pattern and the second conductive pattern are opposed to each other, pressed, and brought into contact with each other to form convex portions of the plate. Some of the ink on the transfer medium surface was transferred to the surface. After that, the surface of the transfer medium coated with the remaining ink and the transparent base material A were opposed to each other, pressed and brought into contact with each other, so that the desired conductive patterned ink 1 was transferred onto the transparent base material A. Next, the conductive patterned ink coating film (dispersion coating film) on the transparent substrate is irradiated with plasma of 1.2 kW for 600 seconds in a reducing atmosphere to remove cuprous oxide in the dispersion coating film. was reduced to copper, and a metal grid transparent electrode A1 having a mesh pattern conductive pattern and a second conductive pattern was obtained by a firing process of forming a sintered film of copper metal component.
<<Evaluation of metal grid transparent electrode>>
[Measurement of line width, gap, film thickness, and calculation of aperture ratio]

For the obtained metal grid transparent electrode A1, the line width W _TCE and film thickness t _TCE of the metal thin line of the conductive pattern, and the gap G _TCE of the conductive pattern were calculated from a plane photograph taken with a confocal laser microscope. Table 3 shows the results. The line width _WBus of the fine metal wires of the second conductive pattern of the metal grid transparent electrode A1 was 2 μm, the gap _GBus was 2 μm, and the occupied area ratio _SBus was 75%. The second conductive pattern was electrically connected to the conductive pattern and was used as the current collector on the anode side.
[Measurement of Visible Light Transmittance]

The visible light transmittance T _VLT of the metal grid transparent electrode A1 was calculated by multiplying the visible light transmittance 92.8% of the transparent substrate A by the aperture ratio A _TCE of the conductive pattern. Table 3 shows the results.
[Measurement of sheet resistance]

The sheet resistance of the conductive pattern of the metal grid transparent electrode A1 was measured by a non-contact method using eddy current according to ASTM F 673-02. Table 3 shows the results.
<<Adjustment of Doped Hole Injection Layer>>
[Preparation of doped hole injection layer]

Using a low-molecular-weight host material and a low-molecular-weight dopant obtained from Shine Materials Technology Co. Ltd., co-evaporation with a vacuum deposition device (manufactured by Kurt J. Lesker, product name: Super Spectros thin-film deposition system), A plurality of measurement samples were prepared by depositing doped hole injection layers on the glass substrate and on the comb-shaped electrodes on the glass substrate. The doped hole injection layer of each measurement sample had a dopant density _Np of 5 vol% and 10 vol% by adjusting the deposition rate (Å/sec) and deposition time (sec) of the low-molecular-weight host material and the low-molecular-weight dopant. , 15 vol %, and the film thickness t _HIL was adjusted in the range of 30 nm to 170 nm.
[Measurement of electrical conductivity]

［可視光透過率の測定］ The electrical resistance between comb-shaped electrodes of the measurement sample was measured by Keithley 2440 source measure manufactured by Keithley, and the electrical conductivity σ _HIL was calculated by the method described above. Table 2 summarizes the results of averaging the calculated σ _HIL for each dopant density.

[Measurement of Visible Light Transmittance]

The visible light transmittance of the doped hole injection layer on the glass substrate of each measurement sample was calculated by the following method. By UV-vis spectroscopy using glass substrates as each measurement sample and a reference sample, the light absorption spectrum of the doped hole injection layer with the influence of the glass substrate removed was measured. A transmission spectrum was calculated from the obtained light absorption spectrum, and a visible light transmittance was calculated from the transmission spectrum of the doped hole injection layer according to JIS R 3106:2019 or ISO9050:2003. Thereby, a calibration curve of the visible light transmittance of the doped hole injection layer with respect to the dopant density and film thickness was obtained.
<<Manufacturing of organic EL elements>>
[Deposition of organic functional layer]

A low-molecular-weight organic material obtained from Shine Materials Technology Co. Ltd. was used on the metal grid transparent electrode A1, and a vacuum was applied using a vacuum deposition apparatus (manufactured by Kurt J. Lesker, product name: Super Spectros thin-film deposition system). An organic functional layer having the following structure was formed by a vapor deposition method. The dopant density and film thickness of the doped hole injection layer were adjusted by adjusting the vapor deposition rate (Å/sec) and vapor deposition time (sec) in co-evaporation of the low-molecular-weight host material and the low-molecular-weight dopant.

・Doped hole injection layer: film thickness t _HIL 50 nm, dopant density N _p 5 vol%
・Hole injection layer: film thickness t _HTL 150 nm
・Organic light emitting layer: 15 nm thick, containing blue and yellow fluorescent guest materials ・Electron transport layer: 35 nm thick

The film thickness t _org-TCE of the organic functional layer is 250 nm. For the film thickness of each layer in the organic functional layer, a value calculated from the deposition rate and deposition time when forming each layer was used. As the film thickness of the organic functional layer, the total film thickness of each layer was used. Table 3 shows the sheet resistance and visible light transmittance of the doped hole injection layer calculated from the σ _HIL obtained in <<Adjustment of Doped Hole Injection Layer>> and the calibration curve of the visible light transmittance.
[Deposition of Electron Injection Layer and Cathode]

LiF (thickness: 1 nm) was vacuum-deposited as an electron injection layer on the formed organic functional layer, and Al (thickness: 100 nm) was deposited thereon as a cathode by a vacuum deposition method.

[Formation of sealing layer]
Finally, a thin film encapsulating layer (TFE) disclosed in Non-Patent Document 3 covers the entire organic EL element except for a partial region of the current collector exposed for connection with an external terminal, and the organic EL element is manufactured.

<<Evaluation of current density-voltage-luminance characteristics (JVL characteristics) of organic EL elements>>
JVL characteristics were evaluated for the obtained organic EL device. FIG. 8 shows JVL characteristics. Also, FIG. 9 shows a photograph of the appearance of the organic EL device when 4 V is applied. It was found from the JVL characteristics that the threshold voltage for light emission was 2.3V. Therefore, the leakage current of this organic EL element was defined as the current density when the applied voltage was 1V. Table 3 shows the leakage current and the luminance when 4V is applied.

[Examples A2 to A7 and Comparative Examples A1 to A2]
The line width W _TCE and the gap G _TCE in the conductive pattern of the metal grid transparent electrode were changed as shown in Table 3 by changing the groove pattern of the plate used in the pattern formation process. In addition, the film thickness t _TCE of the thin metal wire was changed as shown in Table 3 by changing the coating film thickness of the ink on the surface of the transfer medium in the pattern forming process. Further, for Examples A1 to A7, the dopant density N _p and film thickness t _HIL of the doped hole injection layer were changed as shown in Table 3 by changing the vapor deposition rate and vapor deposition time during co-evaporation. In Comparative Examples A1 and A2, instead of the doped hole injection layer, a hole injection layer (thickness: 10 nm) made of only a low-molecular-weight host material different from that of Examples A1 to A7 was formed on the electrode portion of the metal grid transparent electrode. was formed by vacuum deposition, and a hole transport layer (thickness: 40 nm) composed of a combination of low-molecular-weight host materials different from those of Examples A1 to A7 was formed on the hole injection layer by vacuum deposition. Other than that, a metal grid transparent electrode and an organic EL device using the metal grid transparent electrode were produced and evaluated in the same manner as in Example A1. Table 3 shows the results.

〔実施例Ａ８〕

[Example A8]

<<Cross-sectional SEM analysis of organic EL element>>
The conductive pattern of the metal grid transparent electrode was adjusted so that the line width W _TCE of the thin metal line was 3 μm, the film thickness t _TCE was 159 nm, and the gap G _TCE of the conductive pattern was 27 μm. A metal grid transparent electrode was produced in the same manner. Further, on the obtained metal grid transparent electrode, a doped hole injection layer adjusted to have a dopant density N _p of 10 vol % and a film thickness t _HIL of 100 nm was provided, in the same manner as in Example A1. device was manufactured. For the obtained organic EL element, using Nova200 NanoLab FIB-SEM manufactured by FEI, an observation cross section including a cross section of the metal fine wire perpendicular to the extending direction of the metal fine wire was formed, and a cross-sectional SEM of the laminate of the organic EL device was performed. got the image. A cross-sectional SEM image is shown in FIG. It can be seen from FIG. 10 that the organic functional layer can completely cover the fine metal wires.

From Examples A1 to A7 and Reference Example S1, a low-molecular-weight organic material is formed on a conductive pattern composed of fine metal wires containing a metal component M (eg, copper) and an oxide of the metal component M (eg, copper oxide). By forming the doped hole injection layer and the hole transport layer by a vapor deposition method, it is possible to solve the problems in the manufacturing process of the organic EL element, such as damage to the fine metal wires and peeling of the fine metal wires from the transparent base material. It can be seen that an organic EL element using a metal grid transparent electrode having thin wires can be realized. Furthermore, from the cross-sectional SEM images of the organic EL devices of Examples A1 to A7, Comparative Examples A1 to A2, and Example A8, the metal grid transparent electrode having a thickness t _TCE of the metal fine wire of 50 nm or more and 250 nm or less, the dope hole By making the injection layer and the hole transport layer thicker than before and adjusting the total film thickness t _org-TCE of the organic functional layers so that (t _org-TCE −t _TCE ) is in the range of 50 nm to 300 nm, It can be seen that an organic EL element using a metal grid transparent electrode with high brightness can be obtained in which short circuits and leak currents are suppressed.

That is, Examples A1 to A7 and Comparative Examples A1 to A2 are common in that the thickness t _TCE of the metal fine wires of the metal grid transparent electrode is 50 nm or more and 250 nm or less, respectively, but the hole injection layer of Comparative Examples A1 to A2 and the thickness of the hole transport layer is 10 nm and 40 nm, respectively, the thicknesses of the hole injection layer and the hole transport layer of Examples A1 to A7 are 30 to 120 nm and 150 nm, respectively, which are large, and as a result, the comparative The thickness of the organic functional layer of Examples A1 to A7 is 230 to 320 nm, compared with the thickness of the organic functional layer of Examples A1 to A2, which is 140 nm.

Since it is known that the luminance decreases as the film thickness increases, the film thickness of the organic functional layer in a normal organic EL element is 100 to 200 nm as in Comparative Examples A1 and A2. However, the organic functional layers of Examples A1 to A7 have a film thickness of 230 to 320 nm by intentionally increasing the film thickness of the hole injection layer and the hole transport layer. By adopting such a configuration, it is possible to suppress leakage current and improve luminance. In addition, by mounting a doped hole injection layer, it became possible to improve the uniformity of luminance. By adopting the configurations of Examples A1 to A7 in this way, it is possible to provide an organic EL device having a metal grid transparent electrode mounted thereon, in which problems such as peeling are suppressed and the luminance is improved. becomes.
<<Example B>>

A preferred range of design of the metal grid transparent electrode for improving the brightness of the organic EL element using the metal grid transparent electrode will be specifically described below.
<<Simulation of organic EL element using metal grid transparent electrode>>
〔simulation〕

The organic EL element using the metal grid transparent electrode of Example A1 was simulated using LAOSS, a large-area organic semiconductor simulator software manufactured by FLUXiM AG. The voltage distribution and spatial luminance distribution of the doped hole injection layer/metal grid transparent electrode were calculated by two-dimensional finite element modeling (2D FEM). Specifically, the local current density is calculated based on the voltage in each element and the J-V (current density-voltage) characteristics converted from experiments, and the local current density diffuses in the planar direction of the metal grid transparent electrode. Calculations were performed until the differential equation representing the relationship between voltage drop and voltage drop according to Ohm's law in the process of applying voltage converged for the entire system, and the voltage distribution was calculated. The spatial luminance distribution was calculated based on the calculated voltage distribution (surface potential distribution) and the LV (luminance-voltage) characteristics converted from the experiment. The input parameters for the simulation are as follows.

・Conductive pattern setting: Mesh pattern, W _TCE 3 μm, G _TCE 27 μm
- Sheet resistance of the metal wiring portion of the metal grid transparent electrode: 1.257Ω/sq.
- Sheet resistance of doped hole injection layer: 2.129×10 ⁹ Ω/sq.
・Applied voltage: 4V
[Comparison between simulation and actual measurement]

FIG. 11 shows a simulation of the spatial luminance distribution when the applied voltage is 4 V in the square mesh pattern 24P1 ((A) in the same figure) and actual measurement (an optical microscope image of the organic EL element during light emission in Example A1) ((B in the same figure). )) shows a comparison. It was confirmed by the simulation that the measured spatial luminance distribution was qualitatively reproduced. Specifically, a tendency was reproduced in which the brightness was highest near the outside of the metal wiring, and decreased sharply as the distance from the metal wiring increased. The luminance of the organic EL device calculated by simulation was 569 cd/m ² , which was close to the measured value of 357 cd/m ² .
More specifically, according to the simulation shown in FIG. 4A, the brightness is highest near the fine metal wire 24, and decreases as the distance from the fine metal wire 24 approaches the center of the rectangular area surrounded by the fine metal wire 24. Similarly, according to the actual measurement in FIG. 4B, the brightness is highest near the metal fine wire 24, and the closer to the center of the rectangular area surrounded by the metal fine wire 24 and away from the metal fine wire 24, the higher the brightness becomes. A spatial luminance distribution with decreasing luminance was observed.
[Design optimization of metal grid transparent electrode by simulation]

Using this simulation, the line width W _TCE of the metal wiring was changed from 0.25 μm to 10 μm, and the gap G _TCE of the conductive pattern was changed in the range of G _TCE /W _TCE of 1.0 or more and G _TCE of 100 μm or less. The luminance in the case was calculated by simulation. FIG. 12 shows the gap _GTCE dependence of the simulated brightness for each line width. Similarly, FIG. 13 shows the (G _TCE · _ATCE ) dependence of the simulated luminance at each line width.

From FIG. 12, the line width W _TCE of the metal wiring of the metal grid transparent electrode is adjusted to 0.25 μm or more and 5.0 μm or less, and at the same time, the gap G _TCE of the conductive pattern is set to G _TCE /W _TCE of 1.0 or more and It can be seen that the brightness of the organic EL element using the metal grid transparent electrode can be improved by adjusting the G _TCE to 50 μm or less. Further, when the aperture ratio of the conductive pattern is A _TCE , the luminance of the organic EL element using the metal grid transparent electrode is increased by adjusting (G _TCE ·A _TCE ) to 0.6 µm·% or more and 30 µm·% or less. It can be seen that further improvement is possible. This reduces the hole diffusion distance (G _TCE ) in the in-plane direction in the opening of the conductive pattern to make the spatial luminance distribution uniform, and at the same time reduces the W _TCE of the metal wiring to reduce the aperture ratio ( _ATCE ). By increasing (reducing the light shielding effect), the brightness of the organic EL element can be improved.
<<Example C>>

An organic EL device using a metal grid transparent electrode having a transparent conductive inorganic compound layer will be specifically described below.
[Example C1]
<<Production and Evaluation of Metal Grid Transparent Electrode C1>>

A metal grid transparent electrode C1 was manufactured in the same manner as the metal grid transparent electrode A1, except that an ITO film having a thickness of 130 nm was formed on the conductive pattern by a sputtering method. For the obtained metal grid transparent electrode A1, the line width W _TCE and film thickness t _TCE of the metal thin line of the conductive pattern, and the gap G _TCE of the conductive pattern were calculated from a plane photograph taken with a confocal laser microscope. Table 4 shows the results.

<<Manufacturing and evaluation of organic EL elements>>
An organic EL device was fabricated in the same manner as in Example A1, except that a doped hole injection layer adjusted to have a dopant density N _p of 10 vol % and a film thickness t _HIL of 100 nm was provided on the obtained metal grid transparent electrode C1. was manufactured and evaluated. Table 4 shows the results. FIG. 14 shows an optical microscope image of the organic EL element during light emission of Example C1 at an applied voltage of 4V. As shown in the figure, sufficient brightness was obtained in the rectangular area surrounded by the thin metal wires 24 .

From Examples A1 and C1, it can be seen that the brightness is further improved by providing a transparent conductive inorganic compound layer such as ITO on the conductive pattern. From the comparison between the optical microscope image (FIG. 11B) of the organic EL device of Example A1 in FIG. 11 and FIG. It is considered that the spatial luminance distribution in the opening is made uniform and the luminance of the organic EL element is further improved.

The organic electroluminescence device using a metal grid transparent electrode that suppresses electrical shorts and leak currents of the present invention and further improves brightness can be suitably used for increasing the area and flexibility of organic EL devices, and industrial have availability on

As described above, the metal grid transparent electrode of the organic EL device according to the present embodiment has a thickness of 50 nm or more. It is possible to reduce the electrical resistance compared to a typical metal grid transparent electrode.

In addition, as the thickness of the metal grid transparent electrode is increased, it becomes necessary to improve the smoothness. The inventors of the present application paid attention to the fact that when applied to a metal grid transparent electrode having fine wires, the fine metal wires tend to peel off easily, and an organic functional layer including a doped hole injection layer made of a low-molecular-weight organic material is provided. We came up with the idea of coating thin metal wires using As described above, it is possible to suppress the problem of peeling by not covering the thin metal wire with PEDOT:PSS, which is a polymer. Furthermore, the use of a doped hole injection layer as the hole injection layer promotes the diffusion of holes into the opening, so that it is possible to improve the uniformity of luminance of the organic EL element.

In addition, when the thickness of the metal fine wire is 50 nm or more and 250 nm or less, the difference between the thickness of the organic functional layer and the thickness of the metal fine wire should be 50 nm or more, that is, the thickness of the organic functional layer should be 100 nm or more. As a result, it has become possible to cover thin metal wires and suppress problems such as short circuits and leak currents. On the other hand, by setting the difference between the thickness of the organic functional layer and the thickness of the thin metal wire to 750 nm or less, that is, by setting the thickness of the organic functional layer to 1000 nm or less, it is possible to suppress the decrease in luminance caused by the thickness. became.

For example, the sum of the thickness of the doped hole injection layer made of a low-molecular-weight organic material and the thickness of the doped hole-transport layer made of a low-molecular-weight organic material constituting the organic functional layer is equal to or greater than the thickness of the fine metal wire, and , 200 nm or more.

As described above, a transparent conductive inorganic compound layer such as ITO may be inserted between the fine metal wires and the organic functional layer. With such a configuration, it has become possible to improve the uniformity of luminance of the organic EL element.

Moreover, the fine metal wires of the metal grid transparent electrode may be manufactured by a printing method. By forming the thin metal wires by the printing method, it is possible to easily form the thin metal wires having a thickness of 50 nm or more. In addition, it becomes possible to easily change the gap between the thin metal wires, the wire width, and the like. The inventors of the present application have found that if the gap between the metal wires is too small, the metal wires block the light, resulting in a decrease in brightness. Focusing on the fact that the brightness is rather lowered due to the absence of the gap, the range of the product of the gap and the aperture ratio for increasing the brightness was derived as described above.

Also, the present invention can be modified in various ways without departing from the gist thereof. For example, some components in one embodiment can be added to other embodiments within the scope of ordinary creativity of those skilled in the art. Also, some components in one embodiment may be replaced with corresponding components in other embodiments.

10 Organic EL element 20 Metal grid transparent electrode 22 Transparent substrate 24 Metal fine wire 24P Conductive pattern (electrode part)
24P1 mesh pattern (square)
24P2 mesh pattern (rectangular)
24P3 mesh pattern (rhombus)
24P4 Honeycomb pattern 24P5 Line pattern 26P Second conductive pattern (current collector)
40 Organic functional layer 42 Doped hole injection layer 44 Hole transport layer 46 Organic light emitting layer 48 Electron transport layer 50 Electron injection layer 60 Cathode
70 thin film sealing layer (sealing layer)
A _TCE aperture ratio G _TCE conductive pattern gap J _leak leak current N _p dopant density of doped hole injection layer R _{s_TCE} sheet resistance of metal grid transparent electrode S _Bus occupied area ratio of second conductive pattern T _VLT metal grid transparent electrode Visible light transmittance t _HIL doped hole injection layer thickness t _HTL hole transport layer thickness t _TCE metal wire thickness t _org - _TCE organic functional layer thickness W _Bus Metal constituting the second conductive pattern Line width of fine line W _TCE Line width of metal fine line forming the first conductive pattern σ Electrical conductivity of _HIL- doped hole injection layer

Claims (21)

An organic electroluminescent element comprising a metal grid transparent electrode, a cathode facing the metal grid transparent electrode, and an organic functional layer provided between the metal grid transparent electrode and the cathode,
The metal grid transparent electrode comprises a transparent substrate and a conductive pattern having metal wiring provided on the transparent substrate,
the metal wiring comprises a metal and an oxide of the metal;
The organic functional layer is provided on the conductive pattern and comprises a doped hole injection layer made of a low-molecular-weight organic material, and a hole-transport layer provided on the doped hole-injection layer and made of a low-molecular-weight organic material,
Furthermore, when t _TCE is the thickness of the metal wiring and t _org-TCE is the thickness of the organic functional layer,
t _TCE is 50 nm or more and 250 nm or less,
(t _org-TCE - t _TCE ) is 50 nm or more and 750 nm or less. An organic electroluminescence device. When W _TCE is the line width of the metal wiring and G _TCE is the gap between the adjacent metal wirings extending in the same direction,
W _TCE is 0.25 μm or more and 5.0 μm or less,
G _TCE is 50 μm or less, and
(G _TCE /W _TCE ) is 1.0 or greater;
The organic electroluminescence device according to claim 1. When _ATCE is the aperture ratio of the conductive pattern,
(G _TCE * A _TCE ) is 0.6 μm·% or more and 30 μm·% or less;
The organic electroluminescence device according to claim 2. The aperture ratio _ATCE of the conductive pattern is 35% or more and less than 100%.
The organic electroluminescence device according to claim 3. When _tHIL is the thickness of the doped hole injection layer,
_tHIL is greater than or equal to 30 nm and less than or equal to 200 nm;
The organic electroluminescence device according to any one of claims 1 to 4. When t _HTL is the film thickness of the hole transport layer,
t _HTL is greater than or equal to 30 nm and less than or equal to 200 nm;
The organic electroluminescence device according to any one of claims 1 to 5. Let σ _HIL be the electrical conductivity of the doped hole injection layer,
σ _HIL is 5×10 ⁻⁵ S/cm or more,
The organic electroluminescence device according to any one of claims 1 to 6. The sheet resistance of the doped hole injection layer is 6.5×10 ⁹ Ω/sq. is the following
The organic electroluminescence device according to any one of claims 1 to 7. The visible light transmittance of the doped hole injection layer is 80% or more and 100% or less.
The organic electroluminescence device according to any one of claims 1 to 8. The dopant density _Np of the doped pole injection layer is 3 vol% or more and 18 vol% or less.
The organic electroluminescence device according to any one of claims 1 to 9. further comprising a transparent conductive inorganic compound layer disposed between the metal grid transparent electrode and the doped hole injection layer;
The organic electroluminescence device according to any one of claims 1 to 10. The transparent conductive inorganic compound layer contains indium tin oxide,
The organic electroluminescence device according to claim 11. The metal grid transparent electrode includes a current collector having a second conductive pattern provided on the transparent substrate and electrically connected to the conductive pattern,
When S _Bus is the occupied area ratio of the second conductive pattern per unit area,
S _Bus is 50% or more and less than 100%,
The organic electroluminescence device according to any one of claims 1 to 12. 14. The organic electroluminescence device according to claim 1, wherein said metal is copper. In the STEM-EDX analysis of the cross section of the metal wiring of the conductive pattern perpendicular to the extending direction of the metal wiring, in the thickness region from the metal wiring interface on the transparent substrate side to 0.10t _TCE to 0.90t _TCE 15. The organic material according to any one of claims 1 to 14, wherein the atomic % ratio O/M _0.10 to _0.90 of oxygen atoms contained in the metal oxide to the metal is 0.01 or more and 1.00 or less. Electroluminescence device. the conductive pattern comprises a mesh pattern;
The organic electroluminescence device according to any one of claims 1 to 15. The conductive pattern is
printing the ink containing the metal on the surface of the transparent substrate by a plate printing process so as to form the conductive pattern;
By a firing step, the printed ink is fired to fuse the metal so as to form a sintered metal component film.
17. The organic electroluminescence device according to any one of claims 1 to 16. The doped hole injection layer is
provided by at least two or more low-molecular-weight organic materials;
The organic electroluminescence device according to any one of claims 1 to 17. The doped hole injection layer is
Provided by co-evaporation of a low-molecular-weight host material and a low-molecular-weight dopant so that the dopant density _Np is 3 vol% or more and 18 vol% or less,
The organic electroluminescence device according to any one of claims 1 to 18. Each layer constituting the organic functional layer is formed of a low-molecular-weight organic material,
The organic electroluminescence device according to any one of claims 1 to 19. further comprising a second transparent conductive inorganic compound layer disposed on the transparent substrate;
21. The organic electroluminescence device according to claim 1, wherein said metal grid transparent electrode is provided on said second transparent conductive inorganic compound layer.

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