JP2015008133A - Transparent electrode, electronic device, and organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a transparent electrode having both of adequate optical transparency and conductivity, and superior durability; an electronic device including such the transparent electrode; and an organic electroluminescent element.SOLUTION: A transparent electrode 1 comprises: a conductive layer 1b; and an intermediate layer 1a provided adjoining the conductive layer. The conductive layer contains silver as a primary component. The intermediate layer contains a compound having represented by the following general formula (1). [In the general formula (1), R, Rand Rindependently represent a hydrogen atom or a substituent group; and Lrepresents a nitrogen-containing aromatic heterocyclic group bonded with a nitrogen atom of an imidazole ring.]

Description

  The present invention relates to a transparent electrode, an electronic device, and an organic electroluminescence element. More specifically, the present invention relates to a transparent electrode having both light transmittance and conductivity, and further excellent in durability, and an electronic device and an organic electroluminescence element including the transparent electrode.

  An organic EL element (also referred to as an organic electroluminescent element) using electroluminescence of an organic material (hereinafter referred to as EL) is a thin film type capable of emitting light at a low voltage of about several V to several tens V. It is a complete solid-state device and has many excellent features such as high brightness, high luminous efficiency, thinness, and light weight. For this reason, it has been attracting attention in recent years as surface light emitters such as backlights for various displays, display boards such as signboards and emergency lights, and illumination light sources.

  Such an organic EL element has a configuration in which a light emitting layer made of an organic material is disposed between two electrodes, and emitted light generated in the light emitting layer passes through the electrode and is extracted outside. For this reason, at least one of the two electrodes is configured as a transparent electrode.

As the transparent electrode, an oxide semiconductor material such as indium tin oxide (SnO ₂ -In ₂ O ₃ : Indium Tin Oxide: ITO) is generally used. Studies aiming at resistance have also been made (see, for example, Patent Documents 1 and 2). However, since ITO uses rare metal indium, the material cost is high, and it is necessary to anneal at about 300 ° C. after film formation in order to reduce resistance.

Therefore, a technique for achieving both light transmittance and conductivity by forming a thin film using an alloy of silver (Ag) and magnesium (Mg) having high electrical conductivity, and zinc ( A technique for forming a thin film using Zn) or tin (Sn) as a raw material, a technique for transmitting light in a short wavelength region by forming a thin film using an alloy of silver and aluminum, and the like have been proposed (for example, patents). See references 3-5.)
However, the resistance value of the electrode disclosed in Patent Document 3 is at most about 100Ω / □, which is insufficient as the conductivity of the electrode. In addition, since magnesium is easily oxidized, there is a problem that deterioration with time is remarkable. there were.
The electrode disclosed in Patent Document 4 has a problem that a sufficient resistance value cannot be obtained. In addition, ZnO-based thin films containing Zn are likely to react with water and change their performance, and SnO ₂ -based thin films containing Sn are difficult to etch.
The resistance value of the electrode disclosed in Patent Document 5 is at most 128 Ω / □, and it cannot be said that the electrode is a transparent electrode having both sufficient light transmittance and conductivity.

On the other hand, an organic EL element in which silver is deposited as a cathode with a film thickness of 15 nm is disclosed (for example, see Patent Document 6).
However, in the silver film disclosed in Patent Document 6, when the film is thinned, it is difficult to maintain electrode characteristics because silver easily migrates, and development of a new technique is desired.

JP 2002-015623 A Japanese Unexamined Patent Publication No. 2006-164961 JP 2006-344497 A JP 2007-031786 A JP 2009-151963 A US Patent Application Publication No. 2011/0260148

  The present invention has been made in view of the above-described problems and circumstances, and the solution to the problem is a transparent electrode having sufficient light transmission and conductivity, and excellent in durability, an electronic device including the transparent electrode, and An organic electroluminescence device is provided.

  As a result of examining the cause of the above-mentioned problem in order to solve the above-mentioned problems, the present inventor is a transparent electrode comprising a conductive layer and an intermediate layer provided adjacent to the conductive layer, The conductive layer contains silver as a main component, and the intermediate layer contains a compound having a structure represented by the following general formula (1), thereby achieving both excellent light transmittance and conductivity. And it discovered that the transparent electrode excellent in durability was realizable, and came to this invention.

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

〔一般式（１）中、Ｒ_１、Ｒ_２及びＲ_３は、それぞれ独立に、水素原子又は置換基を表す。Ｌ_１は、イミダゾール環の窒素原子と結合している含窒素芳香族複素環基を表す。〕 1. A transparent electrode comprising a conductive layer and an intermediate layer provided adjacent to the conductive layer,
The conductive layer contains silver as a main component,
The said intermediate | middle layer contains the compound which has a structure represented by following General formula (1), The transparent electrode characterized by the above-mentioned.

[In General Formula (1), R ₁ , R ₂ and R ₃ each independently represents a hydrogen atom or a substituent. L ₁ represents a nitrogen-containing aromatic heterocyclic group bonded to the nitrogen atom of the imidazole ring. ]

2. 2. The transparent electrode according to item ₁ , wherein L ₁ in the general formula (1) has a nitrogen-containing aromatic six-membered ring skeleton.

3. 3. The transparent electrode according to item 2, wherein L ₁ in the general formula (1) has a pyrimidine ring skeleton or a triazine ring skeleton.

  4). Any one of Items 1 to 3, wherein the intermediate layer contains a compound having a structure represented by General Formula (1) having two or more imidazole ring skeletons in the molecule. The transparent electrode according to one item.

〔一般式（２）中、Ｒ_４〜Ｒ_９は、それぞれ独立に、水素原子又は置換基を表す。Ｌ_２は、芳香族炭化水素環基又は芳香族複素環基を表す。Ｘ_１、Ｘ_２及びＸ_３は、それぞれ独立に、窒素原子又は−ＣＲ_１０を表し、少なくとも一つは窒素原子を表す。Ｒ_１０は、水素原子又は置換基を表す。〕 5. The said intermediate | middle layer contains the compound which has a structure represented by following General formula (2), The transparent electrode as described in any one of Claim 1 to 4 characterized by the above-mentioned.

[In General Formula (2), R < ₄ > -R < ₉ > represents a hydrogen atom or a substituent each independently. L ₂ represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group. X ₁ , X ₂ and X ₃ each independently represent a nitrogen atom or —CR ₁₀ , and at least one represents a nitrogen atom. R ₁₀ represents a hydrogen atom or a substituent. ]

〔一般式（３）中、Ｒ_１１〜Ｒ_１６は、それぞれ独立に、水素原子又は置換基を表す。Ｘ_４、Ｘ_５及びＸ_６は、それぞれ独立に、窒素原子又は−ＣＲ_１７を表し、少なくとも一つは窒素原子を表す。Ｒ_１７は水素原子又は置換基を表す。Ｙ_１〜Ｙ_４は、それぞれ独立に、窒素原子又は−ＣＲ_１８を表し、これらが互いに結合して新たな環を形成しても良い。Ｒ_１８は、水素原子又は置換基を表す。Ｚ_１〜Ｚ_４は、それぞれ独立に、窒素原子又は−ＣＲ_１９を表し、少なくとも一つは窒素原子を表す。これらは互いに結合して新たな環を形成してもよい。Ｒ_１９は、水素原子又は置換基を表す。〕 6). 6. The transparent electrode according to item 5, wherein the structure represented by the general formula (2) is a structure represented by the following general formula (3).

[In General Formula (3), R _{11 to} R ₁₆ each independently represents a hydrogen atom or a substituent. X ₄ , X ₅ and X ₆ each independently represent a nitrogen atom or —CR ₁₇ , and at least one represents a nitrogen atom. R ₁₇ represents a hydrogen atom or a substituent. Y _{1 to} Y ₄ each independently represent a nitrogen atom or —CR ₁₈ , and these may be bonded to each other to form a new ring. R ₁₈ represents a hydrogen atom or a substituent. Z _{1 to} Z ₄ each independently represent a nitrogen atom or —CR ₁₉ , and at least one represents a nitrogen atom. These may combine with each other to form a new ring. R ₁₉ represents a hydrogen atom or a substituent. ]

  7). An electronic device comprising the transparent electrode according to any one of items 1 to 6.

  8). An organic electroluminescence device comprising the transparent electrode according to any one of items 1 to 6.

  According to the present invention, it is possible to provide a transparent electrode having both sufficient light transmittance and conductivity and excellent durability, an electronic device including the transparent electrode, and an organic electroluminescence element.

  Although the expression mechanism and action mechanism of the effect of the present invention are not clarified, it is presumed as follows.

  In the transparent electrode of the present invention, a conductive layer containing silver as a main component is provided adjacent to the intermediate layer, and the intermediate layer comprises a compound having a structure represented by the general formula (1). Contains.

In the general formula (1), a nitrogen atom not bonded to L ₁ is “a nitrogen atom having an unshared electron pair not involved in aromaticity”. As a result, when forming a conductive layer on the upper part of the intermediate layer, the silver atoms constituting the conductive layer interact with nitrogen atoms having unshared electron pairs not involved in the aromaticity contained in the intermediate layer. Thus, the diffusion distance of silver atoms on the surface of the intermediate layer is reduced, and aggregation of silver at a specific location can be suppressed.

  When the compound of the present invention is used for the intermediate layer, the silver atom first forms a two-dimensional nucleus on the surface of the intermediate layer containing the silver affinity compound having an atom having an affinity for the silver atom, The film is formed by a layer growth type (Frank-van der Merwe: FM type) film growth in which a two-dimensional single crystal layer is formed.

In general, silver atoms attached on the surface of the intermediate layer are bonded while diffusing on the surface to form three-dimensional nuclei and grow into three-dimensional islands (Volume- It is considered that the film is easily formed into an island shape by the film growth using the Weber (VW type).
However, in the present invention, island-like growth is caused by the compound having an imidazole skeleton, which is a structure represented by the general formula (1) to the general formula (3), which is a silver affinity compound contained in the intermediate layer. It is presumed that the growth is suppressed and layer growth is promoted.
Accordingly, it is possible to obtain a conductive layer having a uniform thickness even though the layer thickness is thin. As a result, it is possible to obtain a transparent electrode in which conductivity is ensured while maintaining light transmittance with a thinner layer thickness.

Schematic sectional view showing an example of the configuration of the transparent electrode of the present invention Schematic sectional view showing a first example of an organic EL device using the transparent electrode of the present invention Schematic sectional view showing a second example of an organic EL device using the transparent electrode of the present invention Schematic sectional view showing a third example of an organic EL element using the transparent electrode of the present invention Schematic cross-sectional view of an illuminating device having a light-emitting surface enlarged using an organic EL element having a transparent electrode of the present invention Schematic cross-sectional view of a light-emitting panel equipped with an organic EL device produced in the examples

  The transparent electrode of the present invention includes a conductive layer and an intermediate layer provided adjacent to the conductive layer, the conductive layer contains silver as a main component, and the intermediate layer has the general formula ( It contains a compound having a structure represented by 1). This feature is a technical feature common to the inventions according to claims 1 to 8.

In an embodiment of the present invention, from the viewpoint that various molecular structures can be designed and modification is easy organically, L ₁ in the general formula (1) is a nitrogen-containing aromatic six-membered member. It preferably has a ring skeleton. In the general formula (1), it is more preferable that L ₁ has a pyrimidine ring skeleton or a triazine ring skeleton.

  As an embodiment of the present invention, the intermediate layer preferably contains a compound having a structure represented by the general formula (1) having two or more imidazole ring skeletons in the molecule.

  As an embodiment of the present invention, it is preferable that the intermediate layer contains a compound having a structure represented by the general formula (2). As a result, it is possible to achieve both the effect of having a strong interaction and the effect from the point of easiness of synthesis, economical advantages and time advantages.

  As an embodiment of the present invention, the structure represented by the general formula (2) is used from the viewpoint that the crystallinity is lowered when forming a film by eliminating the 120-degree symmetry axis and the film quality is good. The structure represented by the general formula (3) is preferable.

  Moreover, the transparent electrode of this invention can be comprised suitably for an electronic device. Thereby, it is possible to obtain an electronic device having both sufficient light transmission and conductivity and excellent durability.

  Moreover, the transparent electrode of this invention can be comprised suitably for an organic electroluminescent element. Thereby, it is possible to obtain an organic electroluminescence element having both sufficient light transmittance and conductivity and excellent in durability.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.
In addition, "-" shown in this invention is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< 1. Transparent electrode >>
<Configuration of transparent electrode>
As shown in FIG. 1, the transparent electrode 1 includes a conductive layer 1b and an intermediate layer 1a provided adjacent to the conductive layer 1b. Specifically, the transparent electrode 1 has a two-layer structure in which an intermediate layer 1a and a conductive layer 1b are stacked on the intermediate layer 1a. The layers 1b are provided in this order. The intermediate layer 1a is a layer containing a compound having a structure represented by the general formula (1). The conductive layer 1b is a layer composed mainly of silver.
The main component of the conductive layer 1b is a component having the highest component ratio among the components constituting the conductive layer 1b. The composition ratio of silver in the conductive layer 1b is preferably 60% by mass or more, more preferably 90% by mass or more, and particularly preferably 98% by mass or more.
Moreover, the transparency of the transparent electrode 1 means that the light transmittance at a measurement light wavelength of 550 nm is 50% or more.
Further, the sheet resistance value as the transparent electrode 1 is preferably 20Ω / □ or less, and the film thickness is usually selected in the range of 5 to 20 nm, preferably 5 to 12 nm.

  Next, the detailed configuration will be described in the order of the substrate 11 on which the transparent electrode 1 having such a laminated structure is provided, the intermediate layer 1a constituting the transparent electrode 1 and the conductive layer 1b.

(substrate)
Examples of the substrate 11 on which the transparent electrode 1 of the present invention is formed include, but are not limited to, glass and plastic. Further, the substrate 11 may be transparent or opaque. When the transparent electrode 1 of the present invention is used in an electronic device that extracts light from the substrate 11 side, the substrate 11 is preferably transparent. Examples of the transparent substrate 11 that is preferably used include glass, quartz, and a transparent resin film.

  Examples of the glass include silica glass, soda-lime silica glass, lead glass, borosilicate glass, and alkali-free glass. From the viewpoints of adhesion to the intermediate layer 1a, durability, and smoothness, the surface of these glass materials may be subjected to physical treatment such as polishing, if necessary, or from an inorganic or organic material. Or a hybrid film obtained by combining these films may be formed.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Is mentioned.

As described above, a film made of an inorganic material or an organic material, or a hybrid film combining these films may be formed on the surface of the resin film. Such coatings and hybrid coatings have a water vapor permeability (25 ± 0.5 ° C., relative humidity 90 ± 2% RH) measured by a method according to JIS K 7129-1992, 0.01 g / m ² · 24 h. The following barrier films (also referred to as barrier films) are preferable. Furthermore, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ⁻³ ml / m ² · 24 h · atm or less, and the water vapor permeability is 1 × 10 ⁻⁵ g / m ² · A high barrier film of 24 hours or less is preferable.

  The material for forming the barrier film as described above may be any material that has a function of suppressing intrusion of factors that cause deterioration of electronic devices such as moisture and oxygen and organic EL elements. Silicon, silicon nitride, or the like can be used. Furthermore, in order to improve the brittleness of the barrier film, it is more preferable to have a laminated structure of a layer made of these inorganic materials (inorganic layer) and a layer made of organic material (organic layer). Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for producing the barrier film is not particularly limited. For example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method described in JP-A-2004-68143 is particularly preferable.

  On the other hand, when the substrate 11 is made of an opaque material, for example, a metal substrate such as aluminum or stainless steel, a film, an opaque resin substrate, a ceramic substrate, or the like can be used.

(Middle layer)
In the transparent electrode of the present invention, a conductive layer containing silver as a main component is provided adjacent to the intermediate layer, and the intermediate layer comprises a compound having a structure represented by the following general formula (1). Contains.

In general formula (1), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a substituent. L ₁ represents a nitrogen-containing aromatic heterocyclic group bonded to the nitrogen atom of the imidazole ring.

In the general formula (1), a nitrogen atom not bonded to L ₁ is “a nitrogen atom having an unshared electron pair not involved in aromaticity”. Thus, when forming a conductive layer adjacent to the intermediate layer, the silver atoms constituting the conductive layer are contained in the intermediate layer and nitrogen atoms having unshared electron pairs not involved in the aromaticity By interacting with each other, the diffusion distance of silver atoms on the surface of the intermediate layer is reduced, and aggregation of silver at a specific location can be suppressed.

  In the present invention, the “nitrogen atom having an unshared electron pair not involved in aromaticity” is a nitrogen atom having an unshared electron pair, and the unshared electron pair becomes an aromatic property of the unsaturated cyclic compound. A nitrogen atom that is not directly involved as an essential element. That is, a non-localized π electron system on a conjugated unsaturated ring structure (aromatic ring) has a nitrogen atom in which a lone pair is not involved as an essential element for aromatic expression in the chemical structural formula Say.

  Hereinafter, the “nitrogen atom having an unshared electron pair not involved in aromaticity” according to the present invention will be described.

  The nitrogen atom is a Group 15 element and has 5 electrons in the outermost shell. Of these, three unpaired electrons are used for covalent bonds with other atoms, and the remaining two become a pair of unshared electron pairs, so that the number of bonds of nitrogen atoms is usually three.

For example, an amino group (—NR ¹ R ² ), an amide group (—C (═O) NR ¹ R ² ), a nitro group (—NO ₂ ), a cyano group (—CN), a diazo group (—N ₂ ), An azide group (—N ₃ ), a urea bond (—NR ¹ C═ONR ² —), an isothiocyanate group (—N═C═S), a thioamide group (—C (═S) NR ¹ R ² ), and the like. These correspond to the “nitrogen atom having an unshared electron pair not involved in aromaticity” of the present invention. R ¹ and R ² each represent a substituent.

Among these, for example, the resonance formula of a nitro group (—NO ₂ ) can be expressed as follows. Strictly speaking, the unshared electron pair of the nitrogen atom in the nitro group is used for the resonance structure with the oxygen atom, but in the present invention, it is defined that the nitrogen atom of the nitro group also has an unshared electron pair.

On the other hand, a nitrogen atom can also create a fourth bond by utilizing an unshared electron pair. For example, as shown below, tetrabutylammonium chloride (abbreviation: TBAC) is a quaternary ammonium salt in which a fourth butyl group is ionically bonded to a nitrogen atom and has a chloride ion as a counter ion. . Tris (2-phenylpyridine) iridium (III) (abbreviation: Ir (ppy) ₃ ) is a neutral metal complex in which an iridium atom and a nitrogen atom are coordinated. Although these compounds have a nitrogen atom, the lone pair of electrons is used for ionic bond and coordinate bond, respectively. Is not applicable.

  That is, the present invention effectively uses a lone pair of nitrogen atoms that are not used for bonding.

In the structural formulas shown below, the left side shows the structure of tetrabutylammonium chloride (abbreviation: TBAC), and the right side shows the structure of tris (2-phenylpyridine) iridium (III) (abbreviation: Ir (ppy) ₃ ).

  Moreover, a nitrogen atom is general as a hetero atom which can comprise an aromatic ring, and can contribute to the expression of aromaticity. Examples of the “nitrogen-containing aromatic ring” include a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, and a tetrazole ring.

  In the case of a pyridine ring, as shown below, in a conjugated (resonant) unsaturated ring structure arranged in a 6-membered ring, the number of delocalized π electrons is 6, so that 4n + 2 (n = 0 or natural number) ) Satisfies the Hückel rule. Since the nitrogen atom in the 6-membered ring is substituted with —CH═, only one unpaired electron is mobilized to the 6π-electron system, and an unshared electron pair is essential for aromatic expression. Not involved as a thing.

  Therefore, the nitrogen atom of the pyridine ring corresponds to the “nitrogen atom having an unshared electron pair not involved in aromaticity” according to the present invention. The molecular orbital of the pyridine ring is shown below.

  In the case of a pyrrole ring, as shown below, one of the carbon atoms constituting the five-membered ring is substituted with a nitrogen atom, but the number of π electrons is six and satisfies the Hückel rule. A nitrogen-containing aromatic ring. Since the nitrogen atom of the pyrrole ring is also bonded to a hydrogen atom, an unshared electron pair is mobilized to the 6π electron system.

  Therefore, although the nitrogen atom of the pyrrole ring has an unshared electron pair, it has been utilized as an essential element for the expression of aromaticity, and therefore the “unshared electron pair not involved in aromaticity” of the present invention. Does not correspond to "nitrogen atom having".

  The molecular orbital of the pyrrole ring is shown below.

On the other hand, as shown below, the imidazole ring is a nitrogen-containing aromatic ring having a structure in which two nitrogen atoms are substituted at the 1- and 3-positions in a 5-membered ring, and also has 6 π electrons. . The nitrogen atom N ¹ is a pyridine ring-type nitrogen atom in which only one unpaired electron is mobilized to the 6π-electron system, and the unshared electron pair is not used for aromaticity expression. On the other hand, the nitrogen atom N ² is a pyrrole-ring nitrogen atom that mobilizes an unshared electron pair to the 6π electron system.

Therefore, the nitrogen atom N ¹ of the imidazole ring corresponds to the “nitrogen atom having an unshared electron pair not involved in aromaticity” in the present invention. The molecular orbital of the imidazole ring is shown below.

The same applies to a condensed ring compound having a nitrogen-containing aromatic ring skeleton. For example, as shown below, δ-carboline is an azacarbazole compound in which a benzene ring skeleton, a pyrrole ring skeleton, and a pyridine ring skeleton are condensed in this order. The nitrogen atom N ³ of the pyridine ring mobilizes only one unpaired electron, and the nitrogen atom N ⁴ of the pyrrole ring mobilizes an unshared electron pair to the π-electron system, respectively, to form a ring. Together with 11 π electrons from the atoms, the total number of π electrons is 14 aromatic rings.

Therefore, among the two nitrogen atoms of δ-carboline, the nitrogen atom N ³ of the pyridine ring corresponds to the “nitrogen atom having an unshared electron pair not involved in aromaticity” according to the present invention, but the nitrogen of the pyrrole ring The atom N ⁴ does not fall under this.

  Thus, even when the pyridine ring or pyrrole ring is incorporated in a condensed ring compound, its effect is not inhibited or suppressed, and there is no difference from when it is used as a single ring. Absent. The molecular orbital of δ-carboline is shown below.

  As described above, the “nitrogen atom having an unshared electron pair not involved in aromaticity” defined in the present invention expresses a strong interaction between the unshared electron pair and silver which is the main component of the conductive layer. Is important for. Such a nitrogen atom is preferably a nitrogen atom in a nitrogen-containing aromatic ring from the viewpoint of stability and durability.

  The strength of the interaction between the nitrogen atom and silver can be inferred from the strength of the nucleophilicity of the nitrogen atom. That is, the stronger the nucleophilicity, the stronger the coordination power to silver atoms and the stronger the interaction.

  Furthermore, it is known that the strength of nucleophilicity is correlated with the strength of basicity. Since the basicity according to the definition of Bronsted Raleigh is a property of receiving protons, in other words, it can be said that the attack target is a proton.

In order to quantitatively understand the basic strength, it is preferable to refer to the pKa value (acid dissociation constant) of the conjugate acid. The conjugate acid is a form in which protons are added to the base, and the pKa value indicates that the smaller the value, the stronger the acidity (proton releasing ability).
Therefore, the larger the pKa value of the conjugate acid, the stronger the basicity.

HA represents an acid, B represents a base, A ⁻ represents a conjugate base, and HB ⁺ represents a conjugate acid.

  The present invention utilizes the interaction between the nitrogen-containing aromatic ring compound in the intermediate layer and silver. Therefore, from the above viewpoint, the pKa value of the conjugate acid of the main nitrogen-containing aromatic ring compound was referred. For the pKa value, the list at the end of the volume was used (see Table 1), Hiroshi Yamanaka, Satoshi Hino, Masako Nakagawa, Naoko Sakamoto, “New edition of heterocyclic compounds”, Kodansha Scientific, March 1, 2004. .

  From the above viewpoint, it is considered that a stronger interaction is expressed when the intermediate layer contains a compound having many structures derived from the structure represented by the general formula (1). From this, it is preferable that an intermediate | middle layer contains the compound which has a structure represented by General formula (1) which has two or more imidazole frame | skeletons in a molecule | numerator.

  A further preferred embodiment of the present invention is to contain a compound having a structure represented by the general formula (2) in the intermediate layer. The structure of the general formula (2) is a six-membered meta-substituted product, which is preferable in that the site capable of interacting with silver is more effectively arranged.

  Furthermore, from the experimental results, the physical properties of the compound having many structures represented by the general formula (1) are not necessarily excellent. From the experimental results, it is considered that a substituent substituted at positions 1, 3, and 5 represented by the general formula (2) is most preferable from the viewpoint of ease of synthesis, economics, and time.

  The present inventors have also found a preferable form from the viewpoint of improving the film quality of the intermediate layer. The compound contained in the intermediate layer is preferably a highly amorphous film with suppressed crystallinity. In order to suppress crystallinity, it is considered that the symmetry of the structure of the compound should be low to some extent, and the structure represented by the general formula (3) is found to be suitable.

  In the general formula (3), a structure different from that in the general formula (1) is substituted at the 5-position, and a substituted product having substitution positions at the 1, 3, and 5 positions. Since the compound represented by the general formula (3) does not have a 120-degree symmetry axis, the symmetry is lowered, and a better film quality is obtained when a film is formed.

The skeleton formed by Z _{1 to} Z ₄ in the structure substituted at the 5-position of the structure represented by the general formula (3) is a pyridine ring skeleton, and the nitrogen atom contained in the pyridine ring also interacts with silver. To do. Here, the pyridine ring skeleton means that a pyridine ring is included as a partial structure in the structure of the compound.

  In order to realize a highly amorphous film, it is preferable that the whole molecule has a twisted structure. It is because crystallinity is suppressed by making it a three-dimensional structure rather than a planar structure.

  In order to obtain a twisted structure, the rotational movement of each unit around its coupling axis may be inhibited or suppressed. One of the methods is to use a rotation barrier of hydrogen atoms.

  In order to have a twisted structure, it is considered effective to design a hydrogen atom bonded to a ring carbon atom located at the center of the compound and its adjacent unit so that a rotation barrier is generated. . For example, according to the results of molecular orbital calculation, I-53 in which positions 1, 3, and 5 of the benzene ring are substituted shows that the entire molecule has a planar structure without a rotation barrier around the bond axis.

  The unit substituted at the 5-position of the structure represented by the general formula (3) is a 6-membered + 5-membered + 6-membered condensed aromatic heterocycle. For example, I-95 in which carboline is substituted at the 5-position of the benzene ring has a twisted structure according to the molecular orbital calculation result.

  It is clear that a rotation barrier is created between the two hydrogen atoms contained in the six-membered ring of the carboline skeleton and the two hydrogen atoms bonded to the carbon atoms of the central benzene ring skeleton, resulting in a twisted structure. did. Similarly, it was found that a twisted structure was similarly formed when the compound had a nitrogen-containing heterocyclic group at the center. Although the benzene ring also has a twisted structure, it is considered that a strong interaction with silver, which is the main component of the conductive layer, can be expressed by the nitrogen-containing aromatic heterocyclic group.

  From these molecular orbital calculation results, the most preferable form for exhibiting the effect of the present invention is a compound having a structure represented by the general formula (3).

In the present invention, the energy level of LUMO is Gaussian 03 (Gaussian 03, Revision D02, MJ Frisch, et al, Gaussian, Inc., Wallingford CT, 2004. Software for molecular orbital calculation manufactured by Gaussian, USA). ) And using B3LYP / 6-31G * as a keyword to optimize the structure of the target molecular structure (eV unit conversion value).
It is known that the correlation between the calculated value obtained by this method and the experimental value is high as a background to the effectiveness of this calculated value.

  When the compound of the present invention is used for the intermediate layer, the silver atom first forms a two-dimensional nucleus on the surface of the intermediate layer containing the silver affinity compound having an atom having an affinity for the silver atom, The film is formed by layer growth (FM type) film growth in which a two-dimensional single crystal layer is formed.

In general, an island-like growth type (VW type) in which silver atoms attached on the surface of the intermediate layer are bonded while diffusing the surface to form a three-dimensional nucleus and grow into a three-dimensional island shape. It is thought that it is easy to form an island shape by the film growth at
However, in the present invention, island-like growth is caused by the compound having an imidazole skeleton, which is a structure represented by the general formula (1) to the general formula (3), which is a silver affinity compound contained in the intermediate layer. It is presumed that the growth is suppressed and layer growth is promoted.
Accordingly, it is possible to obtain a conductive layer having a uniform thickness even though the layer thickness is thin. As a result, it is possible to obtain a transparent electrode in which conductivity is ensured while maintaining light transmittance with a thinner layer thickness.

  Next, the structures represented by the general formulas (1) to (3) according to the present invention will be described in detail.

[Compound having the structure represented by the general formula (1)]
The intermediate layer 1a according to the present invention is characterized by containing a compound having a structure represented by the following general formula (1).

In general formula (1), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a substituent. L ₁ represents a nitrogen-containing aromatic heterocyclic group bonded to the nitrogen atom of the imidazole ring.

In the general formula (1), examples of the substituent represented by R ₁ , R ₂ and R ₃ include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group). Group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg , Ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl Group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl Group, biphenylyl group, etc.), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, carbazolyl group , A carbolinyl group, a diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), a phthalazinyl group, etc.), a heterocyclic group (eg, a pyrrolidyl group) Imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, , Cyclopentyloxy group, cyclohex Ruoxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio Groups (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio groups (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl groups (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxy) Carbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, Tylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group Etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridyl) Carbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyl) Ruoxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group Dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group) Group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group) Group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, Rusulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group ( For example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, piperidyl group (also called piperidinyl group) ), 2,2,6,6-tetramethylpiperidinyl group), halogen atom (eg, fluorine atom, chlorine atom, bromine atom), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl) Group, pentafluoroethyl Group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphate ester Examples include a group (for example, dihexyl phosphoryl group), a phosphite group (for example, diphenylphosphinyl group), a phosphono group, and the like.
The substituents represented by R ₁ , R ₂ and R ₃ may be further substituted with the above substituents.

In general formula (1), L ₁ preferably has a nitrogen-containing aromatic six-membered ring skeleton. For example, those having a pyridyl group, a pyridazyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, and the like are preferable. In particular, L ₁ preferably has a pyrimidine ring skeleton or a triazine ring skeleton. Here, the nitrogen-containing aromatic six-membered ring skeleton, the pyrimidine ring skeleton, and the triazine ring skeleton represent that the respective partial structures are included as in the pyridine ring skeleton.
The nitrogen-containing aromatic heterocyclic group represented by L ₁ may be substituted with the substituents represented by R ₁ , R ₂ and R ₃ .
The compound having the structure represented by the general formula (1) preferably has a branched substituent in the molecule from the viewpoint of improving heat resistance and excellent long-term storage after film formation. Examples of the substituent having a branched structure include a branched alkyl group, a silyl group having two or more substitutions (for example, a trialkylsilyl group, a triarylsilyl group, etc.), a disubstituted amino group (for example, a dialkylamino group, a diarylamino group). 2) or more substituted groups such as a tolyl group, a xylyl group, a dimethylpyridyl group (preferably a linear or branched substituent group) ) And the like. In addition, as long as the branched structure is maintained, the constituent atoms contained in these branched substituents can be appropriately replaced with other atoms such as an oxygen atom, a nitrogen atom, and a sulfur atom.
Particularly preferred is a branched alkyl group having 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, neopentyl group, dimethyl group. A hexyl group etc. are mentioned.

  Moreover, it is preferable that the intermediate | middle layer 1a contains the compound which has a structure represented by General formula (1) in which the said intermediate | middle layer has two or more imidazole ring frame | skeletons in a molecule | numerator.

  As a method of forming such an intermediate layer 1a, a method using a wet process such as a coating method, an ink jet method, a coating method, a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, etc. And a method using the dry process.

[Compound having structure represented by general formula (2)]
Moreover, it is preferable that the intermediate | middle layer 1a contains the structure represented by following General formula (2).

In General Formula (2), R _{4 to} R ₉ each independently represent a hydrogen atom or a substituent. L ₂ represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group. X ₁ , X ₂ and X ₃ each independently represent a nitrogen atom or —CR ₁₀ , and at least one represents a nitrogen atom. R ₁₀ represents a hydrogen atom or a substituent.

In the general formula (2), examples of the substituent represented by R _{4 to} R ₁₀ include the same substituents as those represented by R ₁ in the general formula (1).
Moreover, the aromatic hydrocarbon ring group or aromatic heterocyclic group represented by L ₂ may be substituted with the substituents represented by R ₁ , R ₂ and R ₃ .

[Compound having structure represented by general formula (3)]
Moreover, it is preferable that the structure represented by General formula (2) is a structure represented by following General formula (3).

In General Formula (3), R _{11 to} R ₁₆ each independently represent a hydrogen atom or a substituent. X ₄ , X ₅ and X ₆ each independently represent a nitrogen atom or —CR ₁₇ , and at least one represents a nitrogen atom. R ₁₇ represents a hydrogen atom or a substituent. Y _{1 to} Y ₄ each independently represent a nitrogen atom or —CR ₁₈ , and these may be bonded to each other to form a new ring. R ₁₈ represents a hydrogen atom or a substituent. Z _{1 to} Z ₄ each independently represent a nitrogen atom or —CR ₁₉ , and at least one represents a nitrogen atom. These may combine with each other to form a new ring. R ₁₉ represents a hydrogen atom or a substituent.

In the general formula (3), examples of the substituent represented by R _{11 to} R ₁₉ include the same substituents as those represented by R ₁ in the general formula (1).

  Although the specific example of the organic compound contained in the intermediate | middle layer 1a of this invention is shown below, it is not limited to this.

The organic compound according to the present invention can be easily synthesized according to a conventionally known synthesis method.
Hereinafter, although an example of the synthesis | combining method of the organic compound contained in the intermediate | middle layer 1a of this invention is shown, this invention is not limited to this.

  [Synthesis Example: Synthesis of Exemplary Compound I-73]

(1) Synthesis of Exemplary Compound I-73 In a 100 ml eggplant flask, a THF (50 ml) solution of δ-carboline (5.5 g, 0.033 mol) was stirred at 0 ° C. for 1 hour. Thereafter, η-BuLi (1.2 eq.) Was gradually added dropwise and stirred until the temperature reached room temperature.
In a 200 ml eggplant flask, a solution of trichlorotriazine (5 g, 0.027 mol) in THF (100 ml) was stirred at room temperature under a nitrogen atmosphere.
To this solution, a η-BuLi solution of δ-carboline was gradually added dropwise from a 100 ml eggplant flask and stirred at room temperature for 4 hours.
Further, a solution of imidazole (4.0 eq.) In THF (50 ml) was added to this solution, and the mixture was stirred at room temperature for 10 hours.
Thereafter, the solution was transferred to a separatory funnel and extracted. Ethyl acetate and saturated brine were added to separate the organic phase and the aqueous phase, and then the organic phase was taken out and evaporated under reduced pressure. The obtained solid was purified by silica gel column chromatography to obtain a white solid (7.4 g, yield 71%) of exemplary compound I-73.

(Conductive layer)
The conductive layer 1b according to the present invention contains silver as a main component. The conductive layer 1b is a layer formed on the intermediate layer 1a.
The conductive layer 1b may have a configuration in which a layer mainly composed of silver is divided into a plurality of layers as necessary.

The conductive layer 1b preferably has a layer thickness in the range of 5 to 20 nm, and more preferably in the range of 5 to 12 nm.
When the layer thickness is less than 20 nm, the absorption component or reflection component of the layer is reduced, and the light transmittance of the transparent electrode 1 is preferably improved. Further, it is preferable that the layer thickness is thicker than 5 nm because the conductivity of the layer becomes sufficient.

  Note that, in the transparent electrode 1 having a laminated structure including the intermediate layer 1a as described above and the conductive layer 1b formed thereon, the upper part of the conductive layer 1b may be covered with a protective film. Another conductive layer may be laminated. In this case, it is preferable that the protective film and another conductive layer have light transmittance so that the light transmittance of the transparent electrode 1 is not impaired. Moreover, it is good also as a structure which provided the layer as needed also under the intermediate | middle layer 1a, ie, between the intermediate | middle layer 1a and the board | substrate 11. FIG.

  The conductive layer 1b may be composed of an alloy containing silver (Ag) as a main component. Examples of such an alloy include silver magnesium (AgMg), silver copper (AgCu), and silver palladium (AgPd). ), Silver palladium copper (AgPdCu), silver indium (AgIn), and the like.

As a method for forming the conductive layer 1b, a wet process such as a coating method, an inkjet method, a coating method, or a dip method, a dry method such as a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like is used. Examples include a method using a process.
When forming the conductive layer 1b by a wet method, it is preferable to use a conductive ink containing silver as a main component and containing an organic solvent. As an organic solvent, a conventionally well-known thing can be especially used without a restriction | limiting, unless the effect of the transparent electrode 1 of this invention is inhibited.

  Further, the conductive layer 1b is formed on the intermediate layer 1a, so that the conductive layer 1b is sufficiently conductive even without a high-temperature annealing process (for example, a heating process at 150 ° C. or higher) after the formation of the conductive layer. Although it is characterized by having, it may have been subjected to high-temperature annealing treatment after film formation, if necessary.

<Effect of transparent electrode>
The transparent electrode 1 having the above-described configuration is composed mainly of silver on the intermediate layer 1a containing the compound having the structure represented by any one of the general formulas (1) to (3). A conductive layer 1b is provided. Thereby, when forming the conductive layer 1b on the upper part of the intermediate layer 1a, the silver atoms contained in the conductive layer 1b of the above general formulas (1) to (3) are contained in the intermediate layer 1a. It interacts with a compound having a structure represented by any one, the diffusion distance of silver atoms on the surface of the intermediate layer 1a is reduced, and aggregation of silver is suppressed.

Here, in the formation of a conductive layer generally composed of silver as a main component, the thin film is grown in an island-like growth type (VW type), so that silver particles are easily isolated in an island shape. When the thickness is thin, it is difficult to obtain conductivity, and the sheet resistance value becomes high.
Therefore, it is necessary to increase the film thickness in order to ensure conductivity. However, if the film thickness is increased, the light transmittance is lowered, which is not suitable as a transparent electrode.

  However, according to the transparent electrode 1 of the configuration of the present invention, since aggregation of silver is suppressed on the intermediate layer 1a as described above, in the film formation of the conductive layer 1b composed mainly of silver, the layered A thin film is grown by the growth type (FM type).

  In addition, the transparency of the transparent electrode 1 of the present invention means that the light transmittance at a measurement light wavelength of 550 nm is 50% or more, but each of the above materials used as the intermediate layer 1a is mainly composed of silver. Compared with the conductive layer 1b, a film having sufficiently good light transmittance is formed. On the other hand, the conductivity of the transparent electrode 1 is ensured mainly by the conductive layer 1b. Therefore, as described above, the conductive layer 1b composed mainly of silver has a thinner layer to ensure conductivity, thereby improving the conductivity and light transmission of the transparent electrode 1. It is possible to achieve a balance with improvement in performance.

≪2. Applications of transparent electrodes >>
The transparent electrode 1 having the above-described configuration can be used for various electronic devices. Examples of electronic devices include organic EL elements, LEDs (Light Emitting Diodes), liquid crystal elements, solar cells, touch panels, etc. As electrode members that require light transmission in these electronic devices, the above-mentioned transparent The electrode 1 can be used.
Below, embodiment of the organic EL element using the transparent electrode 1 of this invention is described as an example of a use.

≪3. First example of organic EL element >>
<Configuration of organic EL element>
FIG. 2 is a schematic cross-sectional view showing a first example of an organic EL element using the transparent electrode 1 described above as an example of the electronic device of the present invention.
Below, the structure of an organic EL element is demonstrated based on this figure.

  As shown in FIG. 2, the organic EL element 100 is provided on a transparent substrate (substrate) 13, and in order from the transparent substrate 13 side, an organic functional layer 3 configured using the transparent electrode 1, an organic material, and the like. The counter electrode 5a is laminated in this order. In the organic EL element 100, the transparent electrode 1 of the present invention described above is used as the transparent electrode 1. For this reason, the organic EL element 100 is configured to extract the generated light (hereinafter referred to as emission light h) from at least the transparent substrate 13 side.

  Further, the layer structure of the organic EL element 100 is not limited to the example described below, and may be a general layer structure. Here, the transparent electrode 1 functions as an anode (that is, an anode), and the counter electrode 5a functions as a cathode (that is, a cathode). In this case, for example, the organic functional layer 3 has a structure in which a hole injection layer 3a / a hole transport layer 3b / a light emitting layer 3c / an electron transport layer 3d / an electron injection layer 3e are stacked in this order from the transparent electrode 1 side which is an anode. Although illustrated, it is essential to have at least the light emitting layer 3c composed of an organic material. The hole injection layer 3a and the hole transport layer 3b may be provided as a hole transport injection layer. The electron transport layer 3d and the electron injection layer 3e may be provided as an electron transport injection layer. Of these organic functional layers 3, for example, the electron injection layer 3e may be made of an inorganic material.

  In addition to these layers, the organic functional layer 3 may have a hole blocking layer, an electron blocking layer, or the like laminated as necessary. Furthermore, the light emitting layer 3c may have a structure in which each color light emitting layer that generates light emitted in each wavelength region is laminated, and each of these color light emitting layers is laminated via a non-light emitting auxiliary layer. The auxiliary layer may function as a hole blocking layer or an electron blocking layer. Furthermore, the counter electrode 5a as a cathode may also have a laminated structure as necessary. In such a configuration, only a portion where the organic functional layer 3 is sandwiched between the transparent electrode 1 and the counter electrode 5 a becomes a light emitting region in the organic EL element 100.

  In the layer configuration as described above, the auxiliary electrode 15 may be provided in contact with the conductive layer 1 b of the transparent electrode 1 for the purpose of reducing the resistance of the transparent electrode 1.

  The organic EL element 100 having the above configuration is sealed with a sealing material 17 described later on the transparent substrate 13 for the purpose of preventing deterioration of the organic functional layer 3 configured using an organic material or the like. ing. The sealing material 17 is fixed to the transparent substrate 13 side with an adhesive 19. However, it is assumed that the terminal portions of the transparent electrode 1 and the counter electrode 5a are provided on the transparent substrate 13 so as to be exposed from the sealing material 17 in a state of being insulated from each other by the organic functional layer 3.

  Hereinafter, the details of the main layers for constituting the organic EL element 100 described above will be described in terms of the transparent substrate 13, the transparent electrode 1, the counter electrode 5a, the light emitting layer 3c of the organic functional layer 3, the other layers of the organic functional layer 3, and the auxiliary. The electrode 15 and the sealing material 17 will be described in this order.

(Transparent substrate)
The transparent substrate 13 is the substrate 11 on which the transparent electrode 1 of the present invention described above is provided, and among the substrates 11 described above, the transparent substrate 11 having optical transparency is used.

(Transparent electrode (anode))
The transparent electrode 1 is the transparent electrode 1 of the present invention described above, and has a configuration in which an intermediate layer 1a and a conductive layer 1b are sequentially formed from the transparent substrate 13 side. Here, in particular, the transparent electrode 1 functions as an anode, and the conductive layer 1b is a substantial anode.

(Counter electrode (cathode))
The counter electrode 5a is an electrode film that functions as a cathode for supplying electrons to the organic functional layer 3, and is made of a metal, an alloy, an organic or inorganic conductive compound, or a mixture thereof. Specifically, aluminum, silver, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO ₂ , An oxide semiconductor such as SnO ₂ can be given.

The counter electrode 5a can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering.
Further, the sheet resistance value as the counter electrode 5a is preferably several hundred Ω / □ or less, and the film thickness is usually selected within a range of 5 nm to 5 μm, preferably 5 to 200 nm.

  In addition, when this organic EL element 100 takes out the emitted light h also from the counter electrode 5a side, the counter electrode is made of a conductive material having a good light transmission property selected from the above-described conductive materials. 5a should just be comprised.

(Light emitting layer)
The light emitting layer 3c contains a light emitting material, and among them, it is preferable that a phosphorescent dopant (phosphorescent material, phosphorescent compound, phosphorescent compound) is contained as the light emitting material.

  The light emitting layer 3c is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer 3d and holes injected from the hole transport layer 3b, and the light emitting portion is the light emitting layer 3c. Even within the layer, it may be the interface between the light emitting layer 3c and the adjacent layer.

  There is no restriction | limiting in particular in the structure as such a light emitting layer 3c, if the light emitting material contained satisfies the light emission requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. In this case, it is preferable to have a non-light emitting auxiliary layer (not shown) between the light emitting layers 3c.

  The total thickness of the light emitting layer 3c is preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 30 nm because a lower driving voltage can be obtained. In addition, the sum total of the layer thickness of the light emitting layer 3c is a layer thickness also including the said auxiliary layer, when a nonluminous auxiliary layer exists between the light emitting layers 3c.

  In the case of the light emitting layer 3c having a configuration in which a plurality of layers are laminated, the thickness of each light emitting layer is preferably adjusted within a range of 1 to 50 nm, and more preferably adjusted within a range of 1 to 20 nm. When the plurality of stacked light emitting layers correspond to the respective emission colors of blue, green, and red, there is no particular limitation on the relationship between the thicknesses of the blue, green, and red light emitting layers.

  The light emitting layer 3c configured as described above is formed by using a known thin film forming method such as a vacuum evaporation method, a spin coating method, a casting method, an LB method, or an ink jet method, for example, by using a light emitting material or a host compound described later. Can be formed.

  The light emitting layer 3c may be configured by mixing a plurality of light emitting materials, and a phosphorescent light emitting dopant (phosphorescent compound) and a fluorescent dopant (fluorescent light emitting material, fluorescent compound) are mixed. It may be configured.

  The light emitting layer 3c contains a host compound (light emitting host) and a light emitting material (light emitting dopant), and it is preferable that the light emitting material emits more light.

(Host compound)
As the host compound contained in the light emitting layer 3c, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in the light emitting layer 3c.

  As a host compound, a well-known host compound may be used independently, or multiple types may be used. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. In addition, by using a plurality of kinds of light emitting materials described later, it is possible to mix different light emission, thereby obtaining an arbitrary light emission color.

  The host compound used may be a conventionally known low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). .

As the known host compound, a compound having a hole transporting ability and an electron transporting ability while preventing the emission of light from being increased in wavelength and having a high Tg (glass transition temperature) is preferable.
The glass transition temperature here is a value obtained by a method based on JIS K 7121-2012 using DSC (Differential Scanning Colorimetry).

  As specific examples of known host compounds, compounds described in the following documents may be used. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. No. 2002-302516, No. 2002-305083, No. 2002-305084, No. 2002-308837, No. 2003/0175553, No. 2006/0280965. US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0017330, US Patent Application Publication No. 2009/0030202, US Patent Application Publication No. 2005/0238919 ,Country Publication No. 2001/039234, International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/063796, International Publication No. International Publication No. 2007/063754, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. Examples include 2012/023947, JP 2008-074939 A, JP 2007-254297 A, and European Patent No. 2034538.

(Luminescent material)
(1) Phosphorescence emission dopant As a luminescent material which can be used by this invention, a phosphorescence emission dopant is mentioned.

  A phosphorescent dopant is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.). Although defined as being a compound of 01 or more, a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in a solution can be measured using various solvents, but when using a phosphorescent dopant in the present invention, the above phosphorescence quantum yield (0.01 or more) is achieved in any solvent. It only has to be done.

There are two types of light emission principles of the phosphorescent dopant.
One is that recombination of carriers occurs on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant to obtain light emission from the phosphorescent dopant. It is an energy transfer type.
The other is a carrier trap type in which the phosphorescent dopant becomes a carrier trap, and carrier recombination occurs on the phosphorescent dopant to emit light from the phosphorescent dopant. In any case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  The phosphorescent light emitting dopant can be appropriately selected from known materials used for the light emitting layer of a general organic EL device, and preferably contains a group 8-10 metal in the periodic table of elements. A complex compound, more preferably an iridium compound, an osmium compound, a platinum compound (platinum complex compound), or a rare earth complex, and most preferably an iridium compound.

  In the present invention, at least one light emitting layer 3c may contain two or more phosphorescent light emitting dopants, and the concentration ratio of the phosphorescent light emitting dopant in the light emitting layer 3c varies in the thickness direction of the light emitting layer 3c. It may be.

  The phosphorescent dopant is preferably 0.1% by volume or more and less than 30% by volume with respect to the total amount of the light emitting layer 3c.

Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.
Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 /. No. 0202194, U.S. Patent Application Publication No. 2007/0087321, U.S. Patent Application Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Application Publication No. 2002/0034656, and US Pat. No. 7,332,232. US Patent Application Publication No. 2009/0108737, US Patent Application Publication No. 2009/0039776, US Patent No. 6921915, US Patent No. 6,687,266, US Patent Application Publication No. 2007/0190359. Specification, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/0165846, US Patent Application Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. No. 7396598 , U.S. Patent Application Publication No. 2006/0263635, U.S. Patent Application Publication No. 2003/0138657, U.S. Patent Application Publication No. 2003/0152802, U.S. Patent No. 7090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Application Publication No. 2006/0251923, US Patent Application Publication No. 2005/0260441, US Pat. No. 7,393,599. Description, US Pat. No. 7,534,505, US Pat. No. 7,445,855, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2008/0297033, US Pat. No. 7,338,722 , US special Published Patent Application No. 2002/0134984, U.S. Pat. No. 7,279,704, U.S. Patent Application Publication No. 2006/098120, U.S. Patent Application Publication No. 2006/103874, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228583, USA No. 2012/212126, JP 2012-069737, JP 2011-181303, JP 2009-1114086, JP 2003-81988, JP 2002-302671. Japanese Patent Laid-Open No. 2002-363552.
Among these, a preferable phosphorescent dopant includes an organometallic complex having Ir as a central metal. More preferably, a complex containing at least one coordination mode among a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond is preferable.

(2) Fluorescent dopant The fluorescent luminescent dopant (henceforth "fluorescent dopant") based on this invention is demonstrated.
The fluorescent dopant according to the present invention is a compound that can emit light from an excited singlet, and is not particularly limited as long as light emission from the excited singlet is observed.
The fluorescent dopant according to the present invention includes coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes. Stilbene dyes, polythiophene dyes, rare earth complex phosphors, and the like.
In recent years, light emitting dopants utilizing delayed fluorescence have been developed, and these may be used.
Specific examples of the luminescent dopant using delayed fluorescence include, for example, the compounds described in International Publication No. 2011/156793, Japanese Patent Application Laid-Open No. 2011-213643, Japanese Patent Application Laid-Open No. 2010-93181, and the like. Is not limited to these.

(Injection layer: hole injection layer, electron injection layer)
The injection layer is a layer provided between the electrode and the light emitting layer 3c in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and the forefront of its industrialization (November 30, 1998, NT. 2) Chapter 2 “Electrode Materials” (pages 123 to 166) of the 2nd volume of “S. Co., Ltd.”, which includes a hole injection layer 3a and an electron injection layer 3e.

  The injection layer can be provided as necessary. The hole injection layer 3a may be present between the anode and the light emitting layer 3c or the hole transport layer 3b, and the electron injection layer 3e may be present between the cathode and the light emitting layer 3c or the electron transport layer 3d. Good.

  The details of the hole injection layer 3a are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, and the like. Specific examples thereof include phthalocyanine represented by copper phthalocyanine. Examples thereof include a layer, an oxide layer typified by vanadium oxide, an amorphous carbon layer, and a polymer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the electron injection layer 3e are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specifically represented by strontium, aluminum and the like. Examples thereof include a metal layer, an alkali metal halide layer typified by potassium fluoride, an alkaline earth metal compound layer typified by magnesium fluoride, and an oxide layer typified by molybdenum oxide. The electron injection layer 3e is preferably a very thin film, and the layer thickness is preferably in the range of 1 nm to 10 μm, although it depends on the material.

(Hole transport layer)
The hole transport layer 3b is made of a hole transport material having a function of transporting holes, and in a broad sense, the hole injection layer 3a and the electron blocking layer are also included in the hole transport layer 3b. The hole transport layer 3b can be provided as a single layer or a plurality of layers.

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

  Although the above-mentioned thing can be used as a positive hole transport material, It is preferable to use a porphyrin compound, an aromatic tertiary amine compound, and a styryl amine compound, especially an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl, N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD), 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl, 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) quadriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N-diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4'-N, N-diphenylaminostilbenzene, N-phenylcarbazole, and also two fused aromatic rings described in US Pat. No. 5,061,569 In the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308688 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units described in the publication are linked in a starburst type Etc.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. , Applied Physics Letters, 80 (2002), p. A so-called p-type hole transport material as described in 139 can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer 3b is formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. be able to. Although there is no restriction | limiting in particular about the layer thickness of the positive hole transport layer 3b, Usually, 5 nm-about 5 micrometers, Preferably it exists in the range of 5-200 nm. The hole transport layer 3b may have a single layer structure composed of one or more of the above materials.

  Also, the p-type can be enhanced by doping impurities into the material of the hole transport layer 3b. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  Thus, it is preferable to increase the p property of the hole transport layer 3b because an element with lower power consumption can be manufactured.

(Electron transport layer)
The electron transport layer 3d is made of a material having a function of transporting electrons, and in a broad sense, the electron injection layer 3e and the hole blocking layer are also included in the electron transport layer 3d. The electron transport layer 3d can be provided as a single layer structure or a multilayer structure of a plurality of layers.

  An electron transport material for the electron transport layer 3d having a single layer structure and an electron transport material (also serving as a hole blocking material) constituting a layer portion adjacent to the light emitting layer 3c in the electron transport layer 3d having a multilayer structure are injected from the cathode. What is necessary is just to have a function to transmit the emitted electrons to the light emitting layer 3c. As such a material, any one of conventionally known compounds can be selected and used. Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, and oxadiazole derivatives. Further, in the above oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group are also used as the material for the electron transport layer 3d. Can do. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced by Cu, Ca, Sn, Ga, or Pb can also be used as the material for the electron transport layer 3d.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the material for the electron transport layer 3d. Further, a distyrylpyrazine derivative that is also used as the material of the light emitting layer 3c can be used as the material of the electron transport layer 3d, and n-type-Si, n-type as in the case of the hole injection layer 3a and the hole transport layer 3b. An inorganic semiconductor such as -SiC can also be used as the material of the electron transport layer 3d.

  The electron transport layer 3d can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the layer thickness of 3 d of electron carrying layers, Usually, 5 nm-about 5 micrometers, Preferably it exists in the range of 5-200 nm. The electron transport layer 3d may have a single-layer structure made of one or more of the above materials.

  In addition, the electron transport layer 3d can be doped with impurities to increase the n property. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like. Furthermore, it is preferable that the electron transport layer 3d contains potassium, a potassium compound, or the like. As the potassium compound, for example, potassium fluoride can be used. Thus, when the n property of the electron transport layer 3d is increased, an element with lower power consumption can be manufactured.

  Further, as the material (electron transporting compound) of the electron transport layer 3d, the same material as that constituting the intermediate layer 1a described above may be used. The same applies to the electron transport layer 3d also serving as the electron injection layer 3e.

(Blocking layer: hole blocking layer, electron blocking layer)
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic functional layer 3 described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has the function of the electron transport layer 3d in a broad sense. The hole blocking layer is made of a hole blocking material that has a function of transporting electrons but has a very small ability to transport holes, and recombines electrons and holes by blocking holes while transporting electrons. Probability can be improved. Moreover, the structure of said electron carrying layer 3d can be used as a hole-blocking layer as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer 3c.

On the other hand, the electron blocking layer has the function of the hole transport layer 3b in a broad sense. The electron blocking layer is made of a material that has a function of transporting holes but has a very small ability to transport electrons, and improves the probability of recombination of electrons and holes by blocking electrons while transporting holes. be able to. Moreover, the structure of said positive hole transport layer 3b can be used as an electron blocking layer as needed.
The thickness of the hole blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

(Auxiliary electrode)
The auxiliary electrode 15 is provided for the purpose of reducing the resistance of the transparent electrode 1, and is provided in contact with the conductive layer 1 b of the transparent electrode 1. The material for forming the auxiliary electrode 15 is preferably a metal with low resistance such as gold, platinum, silver, copper, or aluminum. Since these metals have low light transmittance, a pattern is formed in a range not affected by extraction of the emitted light h from the light extraction surface 13a. Examples of a method for producing such an auxiliary electrode 15 include a vapor deposition method, a sputtering method, a printing method, an ink jet method, an aerosol jet method, and the like. The line width of the auxiliary electrode 15 is preferably 50 μm or less from the viewpoint of the aperture ratio for extracting light, and the thickness of the auxiliary electrode 15 is preferably 1 μm or more from the viewpoint of conductivity.

(Encapsulant)
The sealing material 17 covers the organic EL element 100 and may be a plate-like (film-like) sealing member that is fixed to the transparent substrate 13 side by the adhesive 19. It may be a stop film. Such a sealing material 17 is provided in a state of covering at least the organic functional layer 3 in a state in which the terminal portions of the transparent electrode 1 and the counter electrode 5a in the organic EL element 100 are exposed. In addition, an electrode may be provided on the sealing material 17 so that the transparent electrode 1 and the terminal portion of the counter electrode 5a of the organic EL element 100 are electrically connected to this electrode.

  Specific examples of the plate-like (film-like) sealing material 17 include a glass substrate, a polymer substrate, a metal substrate, and the like. These substrate materials may be used in the form of a thin film. Examples of the glass substrate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer substrate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal substrate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  Among them, since the element can be thinned, a thin film-like polymer substrate or metal substrate can be preferably used as the sealing material.

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

  Further, the above substrate material may be processed into a concave plate shape and used as the sealing material 17. In this case, the above-described substrate material is subjected to processing such as sandblasting and chemical etching to form a concave shape.

The adhesive 19 for fixing the plate-shaped sealing material 17 to the transparent substrate 13 side seals the organic EL element 100 sandwiched between the sealing material 17 and the transparent substrate 13. It is used as a sealing agent. Specifically, such an adhesive 19 is a photocuring and thermosetting adhesive having a reactive vinyl group of an acrylic acid-based oligomer, a methacrylic acid-based oligomer, a moisture-curing type such as 2-cyanoacrylic acid ester, or the like. Can be mentioned.
In addition, epoxy-based heat and chemical curing type (two-component mixing), hot-melt type polyamide, polyester, polyolefin, and cationic curing type UV-curable epoxy resin adhesive can also be exemplified.

  In addition, the organic material which comprises the organic EL element 100 may deteriorate with heat processing. For this reason, the adhesive 19 is preferably one that can be adhesively cured from room temperature (25 ° C.) to 80 ° C. Further, a desiccant may be dispersed in the adhesive 19.

  Application | coating of the adhesive agent 19 to the adhesion part of the sealing material 17 and the transparent substrate 13 may use a commercially available dispenser, and may print like screen printing.

  In addition, when a gap is formed between the plate-shaped sealing material 17, the transparent substrate 13, and the adhesive 19, in this gap, in the gas phase and the liquid phase, an inert gas such as nitrogen or argon or a fluorine is used. It is preferable to inject an inert liquid such as activated hydrocarbon or silicon oil. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

  On the other hand, when a sealing film is used as the sealing material 17, the organic functional layer 3 in the organic EL element 100 is completely covered and the terminal portions of the transparent electrode 1 and the counter electrode 5a in the organic EL element 100 are exposed. A sealing film is provided on the transparent substrate 13.

  Such a sealing film is configured using an inorganic material or an organic material. In particular, it is made of a material having a function of suppressing entry of a substance that causes deterioration of the organic functional layer 3 in the organic EL element 100 such as moisture and oxygen. As such a material, for example, inorganic materials such as silicon oxide, silicon dioxide, and silicon nitride are used. Furthermore, in order to improve the brittleness of the sealing film, a laminated structure may be formed by using a film made of an organic material together with a film made of these inorganic materials.

  The method for producing these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

(Protective film, protective plate)
A protective film or a protective plate may be provided so as to sandwich the organic EL element 100 and the sealing material 17 together with the transparent substrate 13. This protective film or protective plate is for mechanically protecting the organic EL element 100, and in particular when the sealing material 17 is a sealing film, sufficient mechanical protection is provided for the organic EL element 100. Therefore, it is preferable to provide such a protective film or protective plate.

  As the protective film or protective plate as described above, a glass plate, a polymer plate, a thinner polymer film, a metal plate, a thinner metal film, a polymer material film or a metal material film is applied. In particular, it is preferable to use a polymer film because it is lightweight and thin.

<Method for producing organic EL element>
Here, as an example, a method for manufacturing the organic EL element 100 shown in FIG. 2 will be described.

  First, an intermediate layer 1a containing a compound having a structure represented by any one of the general formulas (1) to (3) on the transparent substrate 13 is a layer of 1 μm or less, preferably 10 to 100 nm. It forms by appropriate methods, such as a vapor deposition method, so that it may become thick. Next, the conductive layer 1b containing silver (or an alloy containing silver) as a main component is appropriately formed by an evaporation method or the like so as to have a layer thickness within a range of 5 to 20 nm, preferably within a range of 8 to 12 nm. A transparent electrode 1 which is formed on the intermediate layer 1a by the method and serves as an anode is produced.

Next, a hole injection layer 3a, a hole transport layer 3b, a light emitting layer 3c, an electron transport layer 3d, and an electron injection layer 3e are formed in this order on this, and the organic functional layer 3 is formed. The film formation of each of these layers includes spin coating, casting, ink jet, vapor deposition, and printing, but vacuum vapor deposition is easy because a homogeneous film is easily obtained and pinholes are difficult to generate. The method or spin coating method is particularly preferred. Further, different film formation methods may be applied for each layer. When employing a vapor deposition method for forming each of these layers, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C. and a degree of vacuum of 1 × 10 ⁻⁶ to 1 × 10 ^−2. It is desirable to appropriately select each condition within the ranges of Pa, vapor deposition rate of 0.01 to 50 nm / second, substrate temperature of −50 to 300 ° C., and layer thickness of 0.1 to 5 μm.

  After the organic functional layer 3 is formed as described above, the counter electrode 5a serving as a cathode is formed thereon by an appropriate film forming method such as a vapor deposition method or a sputtering method. At this time, the counter electrode 5 a is patterned in a shape in which a terminal portion is drawn from the upper side of the organic functional layer 3 to the periphery of the transparent substrate 13 while being kept insulated from the transparent electrode 1 by the organic functional layer 3. Thereby, the organic EL element 100 is obtained. Thereafter, the sealing material 17 that covers at least the organic functional layer 3 is provided in a state where the terminal portions of the transparent electrode 1 and the counter electrode 5a in the organic EL element 100 are exposed.

  As described above, a desired organic EL element is obtained on the transparent substrate 13. In the production of such an organic EL element 100, it is preferable that the organic functional layer 3 to the counter electrode 5a are consistently produced by a single evacuation. A film method may be applied. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  When a DC voltage is applied to the organic EL element 100 thus obtained, the transparent electrode 1 as an anode has a positive polarity, the counter electrode 5a as a cathode has a negative polarity, and a voltage of about 2 to 40V. Luminescence can be observed by applying. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Effect of organic EL element>
The organic EL element 100 described above has a configuration in which the transparent electrode 1 having both light transmittance and conductivity according to the present invention is used as an anode, and an organic functional layer 3 and a counter electrode 5a serving as a cathode are provided thereon. is there. For this reason, the extraction efficiency of the emitted light h from the transparent electrode 1 side is improved while applying a sufficient voltage between the transparent electrode 1 and the counter electrode 5a to realize high luminance light emission in the organic EL element 100. Therefore, it is possible to increase the luminance. Further, it is possible to improve the light emission life by reducing the drive voltage for obtaining a predetermined luminance.

<< 4. Second example of organic EL element >>
<Configuration of organic EL element>
FIG. 3 is a schematic cross-sectional view showing a second example of an organic EL element using the transparent electrode 1 described above as an example of the electronic device of the present invention. The organic EL element 200 of the second example shown in FIG. 3 is different from the organic EL element 100 of the first example shown in FIG. 2 in that the transparent electrode 1 is used as a cathode.
Hereinafter, a detailed description of the same components as those in the first example will be omitted, and a characteristic configuration of the organic EL element 200 in the second example will be described.

  As shown in FIG. 3, the organic EL element 200 is provided on the transparent substrate 13, and the transparent electrode 1 of the present invention described above is used as the transparent electrode 1 on the transparent substrate 13 as in the first example. ing. For this reason, the organic EL element 200 is configured to extract the emitted light h from at least the transparent substrate 13 side. However, the transparent electrode 1 is used as a cathode (cathode). For this reason, the counter electrode 5b is used as an anode.

  The layer structure of the organic EL element 200 configured as described above is not limited to the example described below, and may be a general layer structure as in the first example.

  As an example of the second example, an electron injection layer 3e / electron transport layer 3d / light emitting layer 3c / hole transport layer 3b / hole injection layer 3a are laminated in this order on the transparent electrode 1 functioning as a cathode. The configuration is exemplified. However, it is essential to have at least the light emitting layer 3c made of an organic material.

  In addition to these layers, the organic functional layer 3 employs various configurations as necessary, as described in the first example. In such a configuration, only the portion where the organic functional layer 3 is sandwiched between the transparent electrode 1 and the counter electrode 5 b becomes the light emitting region in the organic EL element 200 as in the first example.

  In the layer structure as described above, the auxiliary electrode 15 may be provided in contact with the conductive layer 1b of the transparent electrode 1 for the purpose of reducing the resistance of the transparent electrode 1. The same as in the example.

Here, the counter electrode 5b used as the anode is composed of a metal, an alloy, an organic or inorganic conductive compound, or a mixture thereof. Specific examples include metals such as gold (Au), oxide semiconductors such as copper iodide (CuI), ITO, ZnO, TiO ₂ , and SnO ₂ .

The counter electrode 5b configured as described above can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering.
Further, the sheet resistance value as the counter electrode 5b is preferably several hundred Ω / □ or less, and the film thickness is usually selected within a range of 5 nm to 5 μm, preferably 5 to 200 nm.

  In addition, when this organic EL element 200 is comprised so that emitted light h can be taken out also from the counter electrode 5b side, as a material which comprises the counter electrode 5b, favorable light transmittance is mentioned among the electrically conductive materials mentioned above. A suitable conductive material is selected and used.

  The organic EL element 200 having the above configuration is sealed with the sealing material 17 in the same manner as in the first example for the purpose of preventing the deterioration of the organic functional layer 3.

  Of the main layers constituting the organic EL element 200 described above, the detailed structure of the constituent elements other than the counter electrode 5b used as the anode and the method for manufacturing the organic EL element 200 are the same as in the first example. For this reason, detailed description is omitted.

<Effect of organic EL element>
The organic EL element 200 described above has a configuration in which the transparent electrode 1 having both light transmittance and conductivity according to the present invention is used as a cathode, and an organic functional layer 3 and a counter electrode 5b serving as an anode are provided thereon. is there. For this reason, as in the first example, a sufficient voltage is applied between the transparent electrode 1 and the counter electrode 5b to realize high-luminance light emission in the organic EL element 200, and light emitted from the transparent electrode 1 side. It is possible to increase the luminance by improving the extraction efficiency of h. Further, it is possible to improve the light emission life by reducing the drive voltage for obtaining a predetermined luminance.

≪5. Third example of organic EL element >>
<Configuration of organic EL element>
FIG. 4 is a schematic cross-sectional view showing a third example of the organic EL element using the transparent electrode 1 described above as an example of the electronic device of the present invention. The organic EL element 300 of the third example shown in FIG. 4 is different from the organic EL element 100 of the first example shown in FIG. 2 in that the counter electrode 5c is provided on the substrate 131 side, and the organic functional layer 3 and It is in the place which laminated | stacked the transparent electrode 1 in this order.
Hereinafter, the detailed description of the same components as those in the first example will be omitted, and the characteristic configuration of the organic EL element 300 in the third example will be described.

  The organic EL element 300 shown in FIG. 4 is provided on a substrate 131, and the counter electrode 5c serving as an anode, the organic functional layer 3, and the transparent electrode 1 serving as a cathode are laminated in this order from the substrate 131 side. . Among these, the transparent electrode 1 of the present invention described above is used as the transparent electrode 1. For this reason, the organic EL element 300 is configured to extract the emitted light h from at least the transparent electrode 1 side opposite to the substrate 131.

  The layer structure of the organic EL element 300 configured as described above is not limited to the example described below, and may be a general layer structure as in the first example.

  An example of the case of the third example is a configuration in which a hole injection layer 3a / a hole transport layer 3b / a light emitting layer 3c / an electron transport layer 3d are stacked in this order on the counter electrode 5c functioning as an anode. The However, it is essential to have at least the light emitting layer 3c configured using an organic material. The electron transport layer 3d also serves as the electron injection layer 3e, and is provided as an electron transport layer 3d having electron injection properties.

  In particular, the characteristic structure of the organic EL element 300 of the third example is that an electron transport layer 3 d having electron injection properties is provided as the intermediate layer 1 a in the transparent electrode 1. That is, in the third example, the transparent electrode 1 used as a cathode is composed of an intermediate layer 1a also serving as an electron transport layer 3d having electron injection properties, and a conductive layer 1b provided on the intermediate layer 1a. It is.

  Such an electron transport layer 3d is configured by using the material constituting the intermediate layer 1a of the transparent electrode 1 described above.

  In addition to these layers, the organic functional layer 3 employs various configurations as necessary, as described in the first example. However, the electron serving as the intermediate layer 1a of the transparent electrode 1 is also used. No electron injection layer or hole blocking layer is provided between the transport layer 3d and the conductive layer 1b of the transparent electrode 1. In the above configuration, only the portion where the organic functional layer 3 is sandwiched between the transparent electrode 1 and the counter electrode 5c becomes the light emitting region in the organic EL element 300, as in the first example.

  In the layer structure as described above, the auxiliary electrode 15 may be provided in contact with the conductive layer 1b of the transparent electrode 1 for the purpose of reducing the resistance of the transparent electrode 1. The same as in the example.

Furthermore, the counter electrode 5c used as the anode is composed of a metal, an alloy, an organic or inorganic conductive compound, or a mixture thereof. Specific examples include metals such as silver (Ag) and gold (Au), and oxide semiconductors such as copper iodide (CuI), ITO, ZnO, TiO ₂ and SnO ₂ .

The counter electrode 5c configured as described above can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering.
Further, the sheet resistance value as the counter electrode 5c is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 5 nm to 5 μm, preferably 5 to 200 nm.

  In addition, when this organic EL element 300 is comprised so that the emitted light h can be taken out also from the counter electrode 5c side, as a material which comprises the counter electrode 5c, light transmittance is favorable among the electrically conductive materials mentioned above. A suitable conductive material is selected and used. In this case, the substrate 131 is the same as the transparent substrate 13 described in the first example, and the surface facing the outside of the substrate 131 is the light extraction surface 131a.

<Effect of organic EL element>
In the organic EL element 300 described above, the electron transport layer 3d having the electron injecting property constituting the uppermost part of the organic functional layer 3 is used as the intermediate layer 1a, and the conductive layer 1b is provided on the intermediate layer 1a. The transparent electrode 1 composed of the conductive layer 1b is provided as a cathode. Therefore, similarly to the first example and the second example, a sufficient voltage is applied between the transparent electrode 1 and the counter electrode 5c to realize high-luminance light emission in the organic EL element 300, while the transparent electrode 1 side. It is possible to increase the luminance by improving the extraction efficiency of the emitted light h from the light source. Further, it is possible to improve the light emission life by reducing the drive voltage for obtaining a predetermined luminance. Further, when the counter electrode 5c is light transmissive, the emitted light h can be extracted from the counter electrode 5c.

  In the third example described above, the intermediate layer 1a of the transparent electrode 1 has been described as also serving as the electron transport layer 3d having electron injection properties. However, the present example is not limited to this, and the intermediate layer 1a may also serve as an electron transport layer 3d that does not have electron injection properties, or the intermediate layer 1a may serve as an electron injection layer instead of an electron transport layer. In addition, the intermediate layer 1a may be formed as an extremely thin film that does not affect the light emitting function of the organic EL element. In this case, the intermediate layer 1a has electron transport properties and electron injection properties. Not.

  Further, when the intermediate layer 1a of the transparent electrode 1 is formed as an extremely thin film that does not affect the light emitting function of the organic EL element, the counter electrode 5c on the substrate 131 side is used as a cathode, The transparent electrode 1 may be an anode. In this case, the organic functional layer 3 is, for example, in order from the counter electrode (cathode) 5c side on the substrate 131, for example, an electron injection layer 3e / electron transport layer 3d / light emitting layer 3c / hole transport layer 3b / hole injection layer 3a. Are stacked. And the transparent electrode 1 which consists of a laminated structure of the ultra-thin intermediate | middle layer 1a and the electroconductive layer 1b is provided in this upper part as an anode.

≪6. Applications of organic EL elements >>
Since the organic EL elements having the above-described configurations are surface light emitters as described above, they can be used as various light emission sources. For example, lighting devices such as home lighting and interior lighting, backlights for watches and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, Examples include a light source of an optical sensor. In particular, it can be effectively used for a backlight of a liquid crystal display device combined with a color filter and a light source for illumination.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a type for directly viewing a still image or a moving image. It may be used as a display device (display). In this case, with the recent increase in the size of lighting devices and displays, the light emitting surface may be enlarged by so-called tiling, in which light emitting panels provided with organic EL elements are joined together in a plane.

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. In addition, a color or full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

  Hereinafter, a lighting device will be described as an example of the application, and then a lighting device in which the light emitting surface is enlarged by tiling will be described.

≪7. Lighting device-1 >>
The lighting device according to the present invention can include the organic EL element.

  The organic EL element used in the lighting device according to the present invention may be designed such that each organic EL element having the above-described configuration has a resonator structure. The purpose of use of the organic EL element configured to have a resonator structure includes a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, a light source of an optical sensor, etc. It is not limited to. Moreover, you may use for the said use by making a laser oscillation.

  In addition, the material used for the organic EL element of this invention is applicable to the organic EL element (white organic EL element) which produces substantially white light emission. For example, a plurality of luminescent colors can be simultaneously emitted by a plurality of luminescent materials, and white light emission can be obtained by mixing colors. As a combination of a plurality of emission colors, those containing the three emission maximum wavelengths of the three primary colors of red, green and blue may be used, or two emission using the complementary colors such as blue and yellow, blue green and orange, etc. It may contain a maximum wavelength.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and excitation of light from the light emitting materials. Any combination with a pigment material that emits light as light may be used, but in a white organic EL element, a combination of a plurality of light-emitting dopants may be used.

  Such a white organic EL element is different from a configuration in which organic EL elements each emitting light are individually arranged in parallel in an array to obtain white light emission, and the organic EL element itself emits white light. For this reason, a mask is not required for film formation of most layers constituting the element, and deposition can be performed on one side by vapor deposition, casting, spin coating, ink jet, printing, etc., and productivity is also improved. To do.

  Moreover, there is no restriction | limiting in particular as a light emitting material used for the light emitting layer of such a white organic EL element, For example, if it is a backlight in a liquid crystal display element, it will fit in the wavelength range corresponding to CF (color filter) characteristic. As described above, any one of the above-described metal complexes and known light-emitting materials may be selected and combined to be whitened.

  If the white organic EL element demonstrated above is used, it is possible to produce the illuminating device which produces substantially white light emission.

≪8. Lighting device-2 >>
FIG. 5 is a schematic cross-sectional view of an illuminating device having a large light emitting surface using a plurality of organic EL elements having the above-described configurations.
As shown in FIG. 5, the illuminating device 21 has a light emitting surface having a large area by arranging a plurality of light emitting panels 22 including the organic EL elements 100 on the transparent substrate 13 on the support substrate 23 (tiling). This is a structured. The support substrate 23 may also serve as the sealing material 17, and each light-emitting panel 22 is tied with the organic EL element 100 sandwiched between the support substrate 23 and the transparent substrate 13 of the light-emitting panel 22. Ring. An adhesive 19 may be filled between the support substrate 23 and the transparent substrate 13, thereby sealing the organic EL element 100. In addition, the edge part of the transparent electrode 1 which is an anode, and the counter electrode 5a which is a cathode are exposed around the light emission panel 22. FIG. However, only the exposed part of the counter electrode 5a is shown in FIG.
In FIG. 5, as the organic functional layer 3 constituting the organic EL element 100, the hole injection layer 3a / the hole transport layer 3b / the light emitting layer 3c / the electron transport layer 3d / the electron injection layer 3e are formed on the transparent electrode 1. A configuration in which the layers are sequentially stacked is shown as an example.

  In the lighting device 21 having such a configuration, the center of each light emitting panel 22 is a light emitting area A, and a non-light emitting area B is generated between the light emitting panels 22. For this reason, a light extraction member for increasing the light extraction amount from the non-light-emitting region B may be provided in the non-light-emitting region B of the light extraction surface 13a. As the light extraction member, a light collecting sheet or a light diffusion sheet can be used.

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

[Example 1]
<< Preparation of transparent electrode >>
As described below, the transparent electrodes 101 to 113, 117, and 120 were fabricated so that the area of the conductive region was 5 cm × 5 cm. The transparent electrodes 101 to 104 were prepared as transparent electrodes having a single layer structure composed of only a conductive layer, and the transparent electrodes 105 to 113, 117 and 120 were prepared as transparent electrodes having a laminated structure of an intermediate layer and a conductive layer. .

(1) Production of transparent electrode 101 First, a transparent non-alkali glass substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus and attached to a vacuum chamber of the vacuum deposition apparatus. Moreover, the resistance heating boat made from tungsten was filled with silver (Ag), and was attached in the said vacuum chamber. Next, after depressurizing the vacuum tank to 4 × 10 ⁻⁴ Pa, the resistance heating boat is energized and heated, and the layer thickness is 5 nm on the substrate within the range of the deposition rate of 0.1 to 0.2 nm / second. A conductive layer made of silver was formed to produce a transparent electrode 101 having a single layer structure.

(2) Production of transparent electrodes 102 to 104 Transparent electrodes 102 to 104 were produced in the same manner as the production of the transparent electrode 101 except that the thickness of the conductive layer was changed to 8 nm, 10 nm, and 15 nm, respectively.

(3) Production of transparent electrode 105 A transparent non-alkali glass substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, Alq ₃ shown below is filled in a tantalum resistance heating boat, and these substrate holder and heating are performed. The boat was attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, the resistance heating boat made from tungsten was filled with silver, and it attached in the 2nd vacuum chamber.

In this state, first, the first vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then heated by energizing a heating boat containing Alq ₃ , within a deposition rate range of 0.1 to 0.2 nm / second. Then, an intermediate layer made of Alq ₃ having a layer thickness of 30 nm was provided on the substrate.

Next, the substrate formed up to the intermediate layer was transferred to the second vacuum chamber in a vacuum, the second vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then the heating boat containing silver was energized and heated, A conductive layer made of silver having a layer thickness of 8 nm was formed within the range of the deposition rate of 0.1 to 0.2 nm / second, and a transparent electrode 105 having a laminated structure of an intermediate layer and a conductive layer was produced.

(4) Production of transparent electrodes 106 to 108 In production of the transparent electrode 105, the transparent electrode 105 was prepared in the same manner except that the constituent materials of the intermediate layer were changed to the comparative compounds (1), (2) and (3) shown above. Electrodes 106 to 108 were produced.

(5) Production of transparent electrode 109 In production of the transparent electrode 105, the transparent electrode 109 was produced in the same manner except that the constituent material of the intermediate layer was changed to I-1 and the layer thickness of the conductive layer was changed to 5 nm. did.

(6) Production of transparent electrodes 110 to 112 Transparent electrodes 110 to 112 were produced in the same manner as the production of the transparent electrode 109 except that the thickness of the conductive layer was changed to 8 nm, 10 nm, and 15 nm, respectively.

(7) Production of transparent electrodes 113 and 117 Transparent electrodes 113 and 117 were produced in the same manner as in the production of transparent electrode 110 except that the constituent material of the intermediate layer was changed to the compounds shown in Table 2.

(8) Production of Transparent Electrode 120 Transparent electrode 120 was produced in the same manner as in production of transparent electrode 117 except that the substrate was changed from a non-alkali glass to a PET (polyethylene terephthalate) film.

<< Evaluation of transparent electrode >>
About the produced transparent electrodes 101-113, 117, and 120, according to the following method, the light transmittance, sheet resistance value, and the light transmittance change (durability) under high temperature storage were measured.

(1) Measurement of light transmittance About each produced transparent electrode, using the spectrophotometer (U-3300 by Hitachi, Ltd.), the light transmittance (%) in the measurement light wavelength 550nm is set for the substrate of each transparent electrode as a reference. It was measured.
The measurement results are shown in Table 2.

(2) Measurement of sheet resistance value About each produced transparent electrode, sheet resistance value (ohm / square) was measured by the 4-probe method constant current application system using the resistivity meter (MCP-T610 by Mitsubishi Chemical Corporation).
The measurement results are shown in Table 2.

(3) Measurement of light transmittance change under high temperature storage Each of the produced transparent electrodes was stored in a temperature 80 ° C./relative humidity 90% RH atmosphere, and the light transmittance change was measured. Specifically, the change in light transmittance after the lapse of 500 hours was evaluated as compared with before the test was started, and the results are shown in Table 2. The light transmittance was measured using a spectrophotometer (U-3300 manufactured by Hitachi, Ltd.), and the light transmittance (%) at a measurement light wavelength of 550 nm was measured using the substrate of each transparent electrode as a reference. The change in light transmittance of each transparent electrode under high temperature storage is shown as a relative value with the change in light transmittance of the transparent electrode 110 as 100.

(4) Summary As is clear from Table 2, the transparent electrodes 109 to 113, 117, and 120 of the present invention in which a conductive layer mainly composed of silver (Ag) is provided on an intermediate layer formed by vapor deposition, In either case, the light transmittance is 54% or more, and the sheet resistance value is suppressed to 17.9Ω / □ or less. In contrast, the transparent electrodes 101 to 108 of the comparative example had a light transmittance of less than 54%, and the sheet resistance value exceeded 17.9Ω / □.
Moreover, also in durability (light transmittance change under high temperature storage), the transparent electrodes 109 to 113, 117, and 120 of the present invention are small in change and excellent as compared with the transparent electrodes 101 to 108 of the comparative example. You can see that
In addition, even in a resin film such as PET (polyethylene terephthalate), by using the compound of the present invention for the intermediate layer, an evaluation result equivalent to that of non-alkali glass was obtained, so that the effect is exhibited regardless of the substrate. I was able to confirm.

  From the above, it was confirmed that the transparent electrode of the present invention has high light transmittance and conductivity, and is further excellent in durability.

[Example 2]
<< Preparation of transparent electrode >>
As described below, the transparent electrodes 201 to 209, 211, 213, and 216 were prepared so that the area of the conductive region was 5 cm × 5 cm. The transparent electrodes 201 and 202 are produced as a single-layer transparent electrode composed of only a conductive layer, and the transparent electrodes 203 to 209, 211, 213, and 216 are transparent electrodes having a laminated structure of an intermediate layer and a conductive layer. Produced.

(1) Production of transparent electrode 201 On a transparent non-alkali glass base material, 0.1 mL of inkjet ink (manufactured by Ink Tec Co., Ltd., TEC-IJ-010) made of complex silver as a conductive layer material, After coating and patterning by spin coating, baking was performed at 130 ° C. for 5 minutes to form a conductive layer made of silver having a layer thickness of 12 nm, and a transparent electrode 201 having a single layer structure was produced.

(2) Production of transparent electrode 202 Transparent electrode 202 was produced in the same manner as in production of transparent electrode 201 except that the thickness of the conductive layer was changed to 20 nm.

(3) Preparation on an alkali-free glass substrate of the transparent electrode 203, using a toluene solution of Alq _3, a thin film was formed by spin coating. An intermediate layer containing Alq ₃ having a layer thickness of 50 nm was provided by heating and drying at 150 ° C. for 1 hour.

  On this intermediate layer, 0.1 mL of inkjet ink (TEC-IJ-010, manufactured by Ink Tec Co., Ltd.) made of complex silver as a conductive layer material was applied and patterned by a spin coating method, and then 5 ° C. at 130 ° C. After baking for a minute, a conductive layer made of silver having a thickness of 12 nm was formed, and a transparent electrode 203 having a laminated structure of an intermediate layer and a conductive layer was produced.

(4) Preparation of transparent electrodes 204 to 206 In the preparation of the transparent electrode 203, the transparent electrodes 204 to 206 were similarly prepared except that the constituent material of the intermediate layer was changed to the comparative compound (1), (2) or (3). Was made.

(5) Production of transparent electrode 207 Transparent electrode 207 was produced in the same manner as production of transparent electrode 203 except that the constituent material of the intermediate layer was changed to I-2.

(6) Production of transparent electrode 208 Transparent electrode 208 was produced in the same manner as production of transparent electrode 207 except that the thickness of the conductive layer was changed to 20 nm.

(7) Production of transparent electrodes 209, 211, and 213 Transparent electrodes 209, 211, and 213 were produced in the same manner as in production of transparent electrode 207, except that the constituent material of the intermediate layer was changed to the compounds shown in Table 3. .

(8) Production of transparent electrode 216 Transparent electrode 216 was produced in the same manner as in production of transparent electrode 213 except that the substrate was changed from non-alkali glass to a PET (polyethylene terephthalate) film.

<< Evaluation of transparent electrode >>
(1) Measurement of light transmittance, sheet resistance value, and light transmittance change under high temperature storage For the prepared transparent electrodes 201-209, 211, 213, and 216, the light transmittance and sheet were the same as in Example 1. The resistance value and light transmittance change (durability) under high temperature storage were measured. The light transmittance change under high temperature storage was measured by storing each of the produced transparent electrodes in a temperature 80 ° C./relative humidity 90% RH atmosphere and measuring the light transmittance change. Specifically, the change in light transmittance after 300 hours was evaluated as compared to before the test was started, and the results are shown in Table 3. The light transmittance was measured using a spectrophotometer (U-3300 manufactured by Hitachi, Ltd.), and the light transmittance (%) at a measurement light wavelength of 550 nm was measured using the substrate of each transparent electrode as a reference. The light transmittance change of each transparent electrode under high-temperature storage is shown as a relative value with the light transmittance change of the transparent electrode 207 of Example 2 as 100.
The results are shown in Table 3.

(2) Summary As is clear from Table 3, the transparent electrodes 207 to 209, 211, 213, and 216 of the present invention in which a conductive layer mainly composed of silver (Ag) is provided on the intermediate layer formed by coating. All have a light transmittance of 50% or more and a sheet resistance value of 13.3 Ω / □ or less. On the other hand, the transparent electrodes 201 to 206 of the comparative example had a light transmittance of 37% or less, and a sheet resistance value greatly exceeding 13.3Ω / □ and 197Ω / □ or more.
Moreover, also in durability (light transmittance change under high temperature storage), the transparent electrodes 207 to 209, 211, 213, and 216 of the present invention are superior to the transparent electrodes 201 to 206 of the comparative example. I understand that.
In addition, even in a resin film such as PET (polyethylene terephthalate), by using the compound of the present invention for the intermediate layer, an evaluation result equivalent to that of non-alkali glass was obtained, so that the effect is exhibited regardless of the substrate. I was able to confirm.

  From the above, it was confirmed that the transparent electrode of the present invention has high light transmittance and conductivity, and is further excellent in durability.

[Example 3]
<Production of light emitting panel>
Double-sided light emitting panels 401 to 408, 410, 413 to 417, 419, and 420 using the transparent electrode of the present invention as an anode were manufactured. Hereinafter, the manufacturing procedure will be described with reference to FIG.

(1) Production of Light-Emitting Panel 401 First, the transparent substrate 101 produced in Example 1, that is, the transparent substrate 13 on which the transparent electrode 1 having only the conductive layer 1b is formed is used as a substrate holder of a commercially available vacuum deposition apparatus. It fixed and the vapor deposition mask was opposingly arranged by the formation surface side of the transparent electrode 1. FIG. Moreover, each material which comprises the organic functional layer 3 was filled in each heating boat in a vacuum evaporation apparatus in the optimal quantity for film-forming of each layer. In addition, what was produced with the resistance heating material made from tungsten was used for the heating boat.

Next, the inside of the vapor deposition chamber of the vacuum vapor deposition apparatus was depressurized to a vacuum degree of 4 × 10 ⁻⁴ Pa, and each layer was formed as follows by sequentially energizing and heating the heating boat containing each material.

  First, a hole-injecting injection layer 31 that serves as both a hole-injecting layer and a hole-transporting layer made of α-NPD is heated by energizing a heating boat containing α-NPD shown below as a hole-transporting injecting material. Was formed on the conductive layer 1 b constituting the transparent electrode 1. At this time, the deposition rate was 0.1 to 0.2 nm / second, and the layer thickness was 20 nm.

  Next, the heating boat containing the host material H4 and the heating boat containing the phosphorescent dopant Ir-4 are energized independently, and the light emitting layer 3c containing the host material H4 and the phosphorescent dopant Ir-4. Was formed on the hole transport injection layer 31. At this time, the energization of the heating boat was adjusted so that the deposition rate was host material H4: phosphorescent dopant Ir-4 = 100: 6. The layer thickness was 30 nm.

  Next, a heating boat containing BAlq shown below as a hole blocking material was energized and heated to form a hole blocking layer 33 made of BAlq on the light emitting layer 3c. At this time, the deposition rate was 0.1 to 0.2 nm / second, and the layer thickness was 10 nm.

  Thereafter, a heating boat containing ET-6 shown below as an electron transporting material and a heating boat containing potassium fluoride were energized independently, and an electron transporting layer 3d containing ET-6 and potassium fluoride. Was formed on the hole blocking layer 33. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-6: potassium fluoride = 75: 25. The layer thickness was 30 nm.

  Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer 3e made of potassium fluoride on the electron transport layer 3d. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 1 nm.

  Thereafter, the transparent substrate 13 formed up to the electron injection layer 3e was transferred from the vapor deposition chamber of the vacuum vapor deposition apparatus to the processing chamber of the sputtering apparatus to which an ITO target as a counter electrode material was attached while maintaining the vacuum state. Next, in the processing chamber, a film was formed at a film forming rate of 0.3 to 0.5 nm / second, and a light-transmitting counter electrode 5a made of ITO having a film thickness of 150 nm was formed as a cathode. As described above, the organic EL element 400 was formed on the transparent substrate 13.

  Thereafter, the organic EL element 400 is covered with a sealing material 17 made of a glass substrate having a thickness of 300 μm, and the adhesive 19 (sealing material) is interposed between the sealing material 17 and the transparent substrate 13 so as to surround the organic EL element 400. ). As the adhesive 19, an epoxy photocurable adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) was used. The adhesive 19 filled between the sealing material 17 and the transparent substrate 13 is irradiated with UV light from the glass substrate (sealing material 17) side to cure the adhesive 19 and seal the organic EL element 400. Stopped.

  In forming the organic EL element 400, an evaporation mask is used for forming each layer, and the central 4.5 cm × 4.5 cm of the 5 cm × 5 cm transparent substrate 13 is defined as the light emitting region A, and the entire circumference of the light emitting region A is formed. A non-light emitting region B having a width of 0.25 cm was provided. Further, the transparent electrode 1 serving as the anode and the counter electrode 5a serving as the cathode are insulated by the organic functional layer 3 from the hole transport injection layer 31 to the electron injection layer 3e, and a terminal portion is provided on the periphery of the transparent substrate 13. Was formed in a drawn shape.

As described above, the light emitting panel 401 in which the organic EL element 400 was provided on the transparent substrate 13 and sealed with the sealing material 17 and the adhesive 19 was manufactured.
In the light emitting panel 401, the emitted light h of each color generated in the light emitting layer 3c is extracted from both the transparent electrode 1 side, that is, the transparent substrate 13 side, and the counter electrode 5a side, that is, the sealing material 17 side.

(2) Production of light-emitting panels 402 to 404 In production of the light-emitting panel 401, the thickness of the conductive layer 1b was changed to 8 nm (transparent electrode 102), 10 nm (transparent electrode 103), and 15 nm (transparent electrode 104), respectively. Similarly, light emitting panels 402 to 404 were manufactured.

(3) Production of Light-Emitting Panel 405 A light-emitting panel 405 was produced in the same manner except that the light-emitting panel 401 was produced using the transparent electrode 105.

(4) Production of light-emitting panels 406 to 408 In production of the light-emitting panel 405, the light-emitting panels 406 to 406 are manufactured in the same manner except that the constituent material of the intermediate layer 1a is changed to the comparative compound (1), (2) or (3). 408 was produced.

(5) Production of light-emitting panels 410 and 413 to 417 In the production of light-emitting panel 405, light-emitting panels 410 and 413 to 417 were produced in the same manner except that the constituent material of intermediate layer 1a was changed to the compounds shown in Table 4. did.

(6) Production of light-emitting panels 419 and 420 Light-emitting panels 419 and 420 were produced in the same manner as the light-emitting panels 416 and 417 except that the substrate was changed from non-alkali glass to a PET (polyethylene terephthalate) film.

<Evaluation of luminous panel>
About the produced light emitting panels 401-408, 410, 413-417, 419, 420, according to the following method, the light transmittance, the sheet resistance value, and the external quantum efficiency (durability) under high temperature storage were measured.

(1) Measurement of light transmittance About each produced light emission panel, using the spectrophotometer (U-3300 by Hitachi, Ltd.), the light transmittance (measurement light wavelength 550nm) with reference to the transparent electrode substrate of each light emission panel ( %).
Table 4 shows the measurement results.

(2) Measurement of sheet resistance value About each transparent electrode contained in the produced light emitting panel, sheet resistance value (Ω / □) was measured by a four-probe method constant current application method using a resistivity meter (MCP-T610 manufactured by Mitsubishi Chemical Corporation). ) Was measured.
Table 4 shows the measurement results.

(3) Measurement of external quantum efficiency (EQE) change under high temperature storage Each of the organic EL devices prepared above was allowed to emit light at room temperature (about 25 ° C.) under a constant current condition of ^2.5 mA / cm ^2. The emission luminance immediately after the start and the emission luminance after 400 hours from the start were measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). Table 4 shows the measurement results.
Relative light emission luminance after 400 hours from the light emission luminance immediately after the start of light emission was obtained, and this was used as a measure of External Quantum Efficiency (EQE). The smaller the value, the smaller the change in emission luminance and the better the external quantum efficiency. The change in external quantum efficiency of each light-emitting panel under high-temperature storage is shown as a relative value where the change in external quantum efficiency of the light-emitting panel 410 of Example 3 (Table 4) is 100.

(4) Summary As is clear from Table 4, each of the light emitting panels 413 to 417, 419, and 420 using the transparent electrode of the present invention as the anode of the organic EL element has a light transmittance of 62% or more. Yes, the sheet resistance value is suppressed to 9.6Ω / □ or less. On the other hand, the light emitting panels 401 to 408 using the transparent electrode of the comparative example as the anode of the organic EL element have a light transmittance of less than 62%, and the sheet resistance value is larger than 9.6Ω / □. The value is shown.
Moreover, it turned out that the light emission panels 413-421 of this invention are excellent also in durability (external quantum efficiency change under high temperature storage) compared with the light emission panels 401-408 of a comparative example.

[Example 4]
<< Preparation of transparent electrode >>
As will be described below, the transparent electrodes 501 to 507 were produced as transparent electrodes having a laminated structure of an intermediate layer and a conductive layer so that the area of the conductive region was 12 cm × 3 cm.

(1) Fabrication of transparent electrode 501 A transparent PET (polyethylene terephthalate) film substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, and the following comparative compound (4) is filled in a tantalum resistance heating boat. The substrate holder and the heating boat were attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, the resistance heating boat made from tungsten was filled with silver, and it attached in the 2nd vacuum chamber.

In this state, first, the first vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then the heating boat containing the comparative compound (4) was energized and heated, and the deposition rate was 0.1 to 0.2 nm / second. In this range, an intermediate layer made of the comparative compound (4) having a layer thickness of 30 nm was provided on the substrate.

Next, the substrate formed up to the intermediate layer was transferred to the second vacuum chamber in a vacuum, the second vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then the heating boat containing silver was energized and heated, A conductive layer made of silver having a layer thickness of 8 nm was formed within a range of a deposition rate of 0.1 to 0.2 nm / second, and a transparent electrode 501 having a laminated structure of an intermediate layer and a conductive layer was produced.

(2) Production of transparent electrode 502 Transparent electrode 502 was produced in the same manner as in production of transparent electrode 501, except that the constituent material of the intermediate layer was changed to comparative compound (5) shown above.

(3) Preparation of transparent electrodes 503 to 507 Transparent electrodes 503 to 507 were prepared in the same manner as in the preparation of the transparent electrode 502 except that the constituent material of the intermediate layer was changed to the compounds shown in Table 5.

<< Evaluation of transparent electrode >>
About the produced transparent electrodes 501-507, according to the following method, the light transmittance and sheet resistance value after high-temperature storage were measured by making light transmittance, sheet resistance value, and a bending state.

(1) Measurement of light transmittance About each produced transparent electrode, using the spectrophotometer (U-3300 by Hitachi, Ltd.), the light transmittance (%) in the measurement light wavelength 550nm is set for the substrate of each transparent electrode as a reference. It was measured.
Table 5 shows the measurement results.

(2) Measurement of sheet resistance value About each produced transparent electrode, sheet resistance value (ohm / square) was measured by the 4-probe method constant current application system using the resistivity meter (MCP-T610 by Mitsubishi Chemical Corporation).
Table 5 shows the measurement results.

(3) Measurement of light transmittance and sheet resistance value after high-temperature storage in a bent state Each transparent electrode produced using a PET film substrate was wound around and fixed to a stainless steel roll having a diameter of 4 cm. These were stored for 200 hours in an atmosphere of 80 ° C./80% relative humidity, and the light transmittance and sheet resistance were measured. The light transmittance was measured using a spectrophotometer (U-3300 manufactured by Hitachi, Ltd.), and the sheet resistance was measured using a resistivity meter (MCP-T610 manufactured by Mitsubishi Chemical Corporation). The results are shown in Table 5.

(4) Summary As is clear from Table 5, the transparent electrodes 504 to 507 of the present invention in which a conductive layer mainly composed of silver (Ag) is provided on an intermediate layer formed by vapor deposition are all light transmissive. The rate is 62% or more, and the sheet resistance value is suppressed to 13.0Ω / □ or less. On the other hand, the transparent electrodes 501 and 502 of the comparative example had a light transmittance of less than 62%, and the sheet resistance value exceeded 13.0Ω / □.
In addition, regarding the durability in a bent state, it can be seen that the transparent electrodes 504 to 507 of the present invention are small and excellent in comparison with the transparent electrodes 501 and 502 of the comparative example.

  From the above, it was confirmed that the transparent electrode of the present invention has high light transmittance and conductivity and is excellent in durability in a bent state.

The transparent electrode using the compound having the structure represented by the general formulas (1) to (3) of the present invention can be used for various electronic devices. Among these, it has been found that the transparent electrode of the present invention can be effectively used in an organic electroluminescence element having the most severe restrictions among electronic devices from the viewpoint of sheet resistance.
Thus, the transparent electrode using the compound having the structure represented by the general formulas (1) to (3) of the present invention is also applied to other electronic devices such as a liquid crystal display device, a solar cell, electronic paper, and a touch panel. It is considered possible.
An organic thin film solar cell and a touch panel were actually produced using the electrode produced with the transparent electrode 117 of Example 1 and confirmed to work well.

  Thereby, it was confirmed that the light emitting panel using the transparent electrode of the present invention can emit light with high luminance with low sheet resistance.

DESCRIPTION OF SYMBOLS 1 Transparent electrode 1a Intermediate | middle layer 1b Conductive layer 3 Organic functional layer 3a Hole injection layer 3b Hole transport layer 3c Light emitting layer 3d Electron transport layer 3e Electron injection layer 31 Hole transport injection layer 33 Hole blocking layers 5a, 5b, 5c Counter electrode 11 Substrate 13, 131 Transparent substrate (substrate)
13a, 131a Light extraction surface 15 Auxiliary electrode 17 Sealing material 19 Adhesive 21 Illumination device 22 Light-emitting panel 23 Support substrate 100, 200, 300, 400 Organic EL element A Light-emitting region B Non-light-emitting region h Light-emitting light

Claims (8)

A transparent electrode comprising a conductive layer and an intermediate layer provided adjacent to the conductive layer,
The conductive layer contains silver as a main component,
The said intermediate | middle layer contains the compound which has a structure represented by following General formula (1), The transparent electrode characterized by the above-mentioned.

[In General Formula (1), R ₁ , R ₂ and R ₃ each independently represents a hydrogen atom or a substituent. L ₁ represents a nitrogen-containing aromatic heterocyclic group bonded to the nitrogen atom of the imidazole ring. ] The transparent electrode according to claim 1, wherein L ₁ in the general formula (1) has a nitrogen-containing aromatic six-membered ring skeleton. Wherein in Formula (1), L ₁ is a transparent electrode according to claim 2, characterized in that it comprises a pyrimidine ring skeleton or a triazine ring skeleton.   The said intermediate | middle layer contains the compound which has a structure represented by General formula (1) which has two or more imidazole ring frame | skeletons in a molecule | numerator, The any one of Claim 1- Claim 3 characterized by the above-mentioned. The transparent electrode according to one item. The said intermediate | middle layer contains the compound which has a structure represented by following General formula (2), The transparent electrode as described in any one of Claim 1- Claim 4 characterized by the above-mentioned.

[In General Formula (2), R < ₄ > -R < ₉ > represents a hydrogen atom or a substituent each independently. L ₂ represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group. X ₁ , X ₂ and X ₃ each independently represent a nitrogen atom or —CR ₁₀ , and at least one represents a nitrogen atom. R ₁₀ represents a hydrogen atom or a substituent. ] 6. The transparent electrode according to claim 5, wherein the structure represented by the general formula (2) is a structure represented by the following general formula (3).

[In General Formula (3), R _{11 to} R ₁₆ each independently represents a hydrogen atom or a substituent. X ₄ , X ₅ and X ₆ each independently represent a nitrogen atom or —CR ₁₇ , and at least one represents a nitrogen atom. R ₁₇ represents a hydrogen atom or a substituent. Y _{1 to} Y ₄ each independently represent a nitrogen atom or —CR ₁₈ , and these may be bonded to each other to form a new ring. R ₁₈ represents a hydrogen atom or a substituent. Z _{1 to} Z ₄ each independently represent a nitrogen atom or —CR ₁₉ , and at least one represents a nitrogen atom. These may combine with each other to form a new ring. R ₁₉ represents a hydrogen atom or a substituent. ]   An electronic device comprising the transparent electrode according to any one of claims 1 to 6.   An organic electroluminescence device comprising the transparent electrode according to any one of claims 1 to 6.

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