JP2009231798A - Organic electroluminescent element, lighting device, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: an organic electroluminescent (EL) element which provides both high light-emitting efficiency and high color purity; a lighting device; and a display. <P>SOLUTION: The organic EL element 1 is constituted by laminating a transparent electrode layer 2, hole injection layer 6, light-emitting layer 4, and reflection electrode layer 3, in this order, on a substrate 5. The distance La between the surface 4a of the transparent electrode layer 2 side of the light-emitting layer 4 and the surface 3b of the light-emitting layer 4 side of the reflection electrode layer 3 satisfies equation (1). In the equation (1), symbol "λo" represents peak wavelength of the derived light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element, a lighting device, and a display device.

  One of the light emitting elements is an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element). The organic EL element includes an anode, a cathode, and a light emitting layer containing an organic substance located between the anode and the cathode. When a voltage is applied to the organic EL element, holes are injected from the anode and electrons are injected from the cathode, and light is emitted by combining these holes and electrons in the light emitting layer. The light emitted from the light emitting layer is usually extracted outside from the anode or the cathode. Therefore, one of the anode and the cathode is composed of a transparent electrode layer that transmits light, and the other electrode is composed of a reflective electrode layer that reflects light emitted from the light emitting layer toward the transparent electrode layer.

  One of the characteristics of the organic EL element is that it can be formed thin, and the distance between the transparent electrode layer and the reflective electrode layer can be made as thin as the wavelength of light. In such a thin element, the light interference effect affects the characteristics of the extracted light. For example, when the interval between the transparent electrode layer and the reflective electrode layer is changed, the extracted light intensity changes in a vibrational manner. It is considered that the light is resonating near the maximum point of the light intensity. An organic EL element that emits light with high light emission efficiency by utilizing the light interference effect by setting the distance between the transparent electrode layer and the reflective electrode layer to a length at which light resonates has been proposed (for example, see Patent Document 1). .

JP 2004-165154 A

  Although the light emission efficiency is increased by designing the organic EL element so that light resonates, not only high light emission efficiency but also high color purity is required for the organic EL element as the light emitting element.

  Accordingly, an object of the present invention is to provide an organic electroluminescence element, a lighting device, and a display device that have both high luminous efficiency and high color purity.

  The light resonating lengths exist discretely. However, the thinner the organic EL element is, the lower the electric resistance of the element is. Therefore, from the viewpoint of light emission efficiency, it is usually the thinnest among light resonating conditions. Although the element is designed under the above conditions, as a result of intensive studies by the present inventors in view of the above problems, it is possible to realize an organic EL element having both high luminous efficiency and high color purity with an element structure different from normal conditions. As a result, the present invention has been completed. That is, this invention provides the following light emitting element, an illuminating device, and a display apparatus.

The present invention comprises a transparent electrode layer,
A reflective electrode layer disposed to face the transparent electrode layer;
A light emitting layer located between the transparent electrode layer and the reflective electrode layer,
A distance La between a surface of the light emitting layer on the transparent electrode layer side and a surface of the reflective electrode layer on the light emitting layer side satisfies the following formula (1).

（式（１）において記号「λｏ」は、取出される光のピーク波長を表す。）
また本発明は、透明電極層と、
前記透明電極層に対向して配置される反射電極層と、
前記透明電極層および前記反射電極層の間に位置する発光層とを含み、
前記発光層の前記反射電極層側の表面と、前記反射電極層の発光層側の表面との間の距離Ｌｂが、次式（２）を満たすことを特徴とする有機エレクトロルミネッセンス素子である。

(In formula (1), the symbol “λo” represents the peak wavelength of the extracted light.)
The present invention also includes a transparent electrode layer,
A reflective electrode layer disposed to face the transparent electrode layer;
A light emitting layer located between the transparent electrode layer and the reflective electrode layer,
A distance Lb between a surface of the light emitting layer on the reflective electrode layer side and a surface of the reflective electrode layer on the light emitting layer side satisfies the following formula (2).

（式（２）において記号「λｏ」は、取出される光のピーク波長を表す。）
また本発明は、前記有機エレクトロルミネッセンス素子を備える照明装置である。

(In formula (2), the symbol “λo” represents the peak wavelength of the extracted light.)
Moreover, this invention is an illuminating device provided with the said organic electroluminescent element.

  Moreover, this invention is a display apparatus provided with two or more said organic electroluminescent elements.

  ADVANTAGE OF THE INVENTION According to this invention, the organic EL element which has both high luminous efficiency and high color purity is realizable.

  FIG. 1 is a front view showing an organic EL element 1 according to an embodiment of the present invention. The organic EL device 1 of the present invention includes a transparent electrode layer 2, a reflective electrode layer 3 disposed opposite to the transparent electrode layer 2, and light emission positioned between the transparent electrode layer 2 and the reflective electrode layer 3. Layer 4. The distance La between the surface 4a of the light emitting layer 4 on the transparent electrode layer 2 side and the surface of the reflective electrode layer 3 on the light emitting layer 4 side (hereinafter sometimes referred to as a reflective surface) 3a is given by Satisfy (1).

式（１）において記号「λｏ」は、取出される光のピーク波長を表す。

In formula (1), the symbol “λo” represents the peak wavelength of the extracted light.

  The organic EL element may include a layer different from the light emitting layer 4 between the transparent electrode layer 2 and the reflective electrode layer 3, or may include a plurality of light emitting layers. The organic EL element 1 of the present embodiment includes a hole injection layer 6 between the light emitting layer 4 and the transparent electrode layer 2, and the transparent electrode layer 2, the hole injection layer 6, and the light emission on the surface of the substrate 5. The layer 4 and the reflective electrode layer 3 are laminated in this order.

  The substrate 5 and the transparent electrode layer 2 transmit visible light in the present embodiment. The reflective electrode layer 3 reflects visible light. When a voltage is applied to the organic EL element 1, light is emitted in all directions from the light emitting portion where light emission occurs in the light emitting layer 4. In a normal organic EL element, when the transparent electrode layer 2 is an anode and the reflective electrode layer 3 is a cathode, when a voltage is applied to the organic EL element, the surface portion of the light emitting layer 4 on the transparent electrode layer 2 side (this embodiment) In the form, light is emitted mainly at a portion in contact with the hole injection layer 6). Since light emission occurs at such a site, the following description will be made in an approximate manner that light emission occurs at the interface between the light emitting layer 4 and the hole injection layer 6 for easy understanding. The surface 4a on the layer 2 side may be referred to as a light emitting surface 4a. Light emitted from the light emitting surface 4a to the substrate 5 side (indicated by an arrow A1 in FIG. 1) is taken out through the hole injection layer 6, the transparent electrode layer 2, and the substrate 5 in this order. Further, light emitted from the light emitting surface 4a to the reflective electrode layer 3 side (indicated by an arrow A2 in FIG. 1) passes through the light emitting layer 4, is reflected by the reflective surface 3b, passes through the light emitting layer 4 again, and becomes a hole. It is taken out through the injection layer 6, the transparent electrode layer 2, and the substrate 5 in this order. That is, the organic EL element 1 of the present embodiment is a so-called bottom emission type element in which light is extracted from the substrate 5 side.

  The light reflected by the reflecting surface 3b and reciprocating once between the light emitting surface 4a and the reflecting surface 3b (hereinafter sometimes referred to as reflected light) and the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side are: Superimposed. The closer the phase difference between the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side and the reflected light (hereinafter, the unit of the light phase is radians unless otherwise specified) is closer to an integral multiple of about 2π. The more the combined light is intensified, and the closer the phase difference is to an odd multiple of π, the weaker the superimposed light is. Therefore, if the phase change of the light when it makes one round trip between the light emitting surface 4a and the reflecting surface 3b is an integral multiple of about 2π, the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side and the reflected light And the light emission efficiency of the organic EL element is increased.

  Specifically, the phase change θ when the light of wavelength λo reciprocates once between the light emitting surface 4a and the reflecting surface 3b is expressed by the following equation (3).

式（３）において、記号「Ｌｏ」は、発光面４ａと反射面３ｂとの間の光学的距離を表し、記号「Φ１」は、反射面３ｂで光が反射される際の位相変化を表す。光学的距離は、屈折率の実部と長さとの積であり、本実施の形態では発光面４ａと反射面３ｂとの間には発光層４のみが配置されるので、本実施の形態における光学的距離Ｌｏは、発光層４の層厚に、発光層４の屈折率の実部を乗じた値である。なお発光面４ａと反射面３ｂとの間に複数の層が設けられる場合には、光学的距離Ｌｏは、各層の表面間の光学的距離を積算した値である。したがって、距離Ｌａと光学的距離Ｌｏとは、１対１に対応する。また一般的に、屈折率ｎ１の物質を伝播する光が、屈折率ｎ１の物質と屈折率ｎ２の物質との界面に垂直入射して反射されると、該界面において反射される光の位相は、次式（４）で表される角度（ラジアン）だけ変化する。

In Expression (3), the symbol “Lo” represents an optical distance between the light emitting surface 4a and the reflecting surface 3b, and the symbol “Φ1” represents a phase change when light is reflected by the reflecting surface 3b. . The optical distance is the product of the real part and the length of the refractive index, and in the present embodiment, only the light emitting layer 4 is disposed between the light emitting surface 4a and the reflecting surface 3b. The optical distance Lo is a value obtained by multiplying the thickness of the light emitting layer 4 by the real part of the refractive index of the light emitting layer 4. When a plurality of layers are provided between the light emitting surface 4a and the reflecting surface 3b, the optical distance Lo is a value obtained by integrating the optical distances between the surfaces of the layers. Therefore, the distance La and the optical distance Lo correspond one-to-one. In general, when light propagating through a material having a refractive index n1 is reflected by being perpendicularly incident on an interface between a material having a refractive index n1 and a material having a refractive index n2, the phase of the light reflected at the interface is The angle changes by the angle (radian) expressed by the following equation (4).

式（４）において、記号「ａｒｇ」は、偏角を表す。式（４）のｎ１，ｎ２にそれぞれ発光層４の屈折率および反射電極層３の屈折率をそれぞれ代入すると、反射面３ｂでの位相変化Φ１が求められる。

In the formula (4), the symbol “arg” represents an argument. By substituting the refractive index of the light emitting layer 4 and the refractive index of the reflective electrode layer 3 respectively into n1 and n2 in Expression (4), the phase change Φ1 on the reflective surface 3b is obtained.

  The condition (θ = 2 × m × π) for which the phase change θ is an integral multiple of 2π is expressed by the following equation (5) when equation (3) is modified.

式（５）において記号「ｍ」は、｛Φ１／（２π）｝よりも大きい整数を表す。以下、説明の便宜のために、ｍのうちで、最も小さい値をｍ１と記載し、ｍ１に（ｓ−１）（記号「ｓ」は自然数を表す）を加算した値を、ｍｓと記載する。

In the formula (5), the symbol “m” represents an integer larger than {Φ1 / (2π)}. Hereinafter, for convenience of explanation, the smallest value among m is described as m1, and a value obtained by adding (s-1) (symbol “s” represents a natural number) to m1 is described as ms. .

  As shown in the equation (5), m takes a discrete value (integer), and therefore the optical distance Lo that satisfies the condition that the phase change θ is an integral multiple of 2π also exists discretely. This optical distance Lo becomes longer as m is larger. That is, as the optical distance Lo is increased, m = m1, m = m2, m = m3,... At the distance La corresponding to the optical distance Lo satisfying the equation (5), the phase change θ is an integral multiple of 2π, so that the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side and the reflected light are strengthened. Fit. Therefore, as the distance La is increased, the light is strengthened, the distances appear sequentially, and the emission intensity changes in a vibrational manner.

  The range represented by Expression (1) is a range including only the second shortest distance La among the distances that become the maximum point of the emission intensity that changes in vibration when the distance La is increased. That is, the distance La in the present embodiment is a distance that satisfies m = m2, or the vicinity thereof. Therefore, since the reflected light and the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side are intensified, an organic EL element with high emission intensity can be realized.

  The shorter the distance La, the lower the electrical resistance of the device and the higher the light emission efficiency. Therefore, in the conventional technique, an organic EL device that satisfies the condition of m = m1 among the optical distance Lo that satisfies the equation (5) is used. I have composed. However, in the present embodiment, by setting the optical distance Lo to m = m2 having a long distance, the spectral width is narrowed and high color purity is realized as will be described later.

  The light emitting layer 4 emits light having a certain spectral width. Therefore, the light emitted from the light emitting layer 4 includes light having a wavelength different from the wavelength λo. For example, when an organic EL element satisfying the formula (5) is configured, the phase changes by an integral multiple of about 2π when light having the wavelength λo makes one round trip between the light emitting surface 4a and the reflecting surface 3b as described above. When light having a wavelength λ1 different from the wavelength λo makes one round trip, the phase change deviates from an integer multiple of about 2π. Since this deviation increases as the deviation from the wavelength λo increases, the effect of strengthening the light decreases as the deviation from the wavelength λo increases in the spectral distribution of the light emitted from the light emitting layer 4. Therefore, by configuring the organic EL element that satisfies the formula (5), it is possible to narrow the extracted light around the wavelength λo.

  As shown in Expression (5), when m is different by 1, the optical distance Lo is different by λo / 2. Since the reflected light makes one round trip of the distance La, the optical distance at the time of one round trip differs by λo when m is different by one. This corresponds to the fact that when m is different by 1, the phase change θ of the wavelength λo is different by 2π. That is, in the case of light of wavelength λo, even if m is increased, the phase change θ does not deviate from an integer multiple of 2π as long as Expression (5) is satisfied. However, in the light of λ1 having a wavelength different from the wavelength λo, the difference between the phase change when the optical distance Lo is reciprocated once and the integer multiple of 2π increases as m increases. For example, if the shift between the phase change when the light of wavelength λ1 reciprocates one optical distance Lo satisfying m = m1 and an integer multiple of 2π is Δψ, the shift when m = m2 is 2Δψ, The deviation when m = m3 is 3Δψ, and the deviation increases as m increases. The greater the difference between the phase change when the optical distance Lo is reciprocated once and the integer multiple of 2π, the smaller the effect of strengthening the light. The greater the m, the greater the effect of narrowing the band. However, as described above, if m is increased and the distance La is increased, the light emission efficiency is lowered. Therefore, in this embodiment, the distance La is set to a length corresponding to m = m2 or the vicinity thereof. The organic EL element 1 having both high luminous efficiency and high color purity is realized.

  Here, the optical distance Lo satisfying m = m2 is specifically calculated based on the configuration of a normal organic EL element. The phase change Φ1 on the reflective surface 3b differs depending on the reflective electrode layer 3 and the members constituting the layer in contact with the reflective electrode layer 3 (the light emitting layer 4 in the present embodiment). Referring to Equation (5), since m1 = 0 and m2 = 1, the optical distance Lo corresponding to m = m2 is 2λo / 3. The distance corresponding to the optical distance Lo differs depending on the refractive index of the member provided between the reflecting surface 3b and the light emitting surface 4a, but the refractive index of this member is approximately the same as the refractive index of organic matter (1.6). ) Is estimated to be λo / 2.4. Expression (1) specifies a range including this λo / 2.4. The distance La is preferably 0.389λo or more and 0.5 or less.

  The present invention can be applied regardless of the emission color, but is preferably used for an organic EL element that emits blue light. In the case of blue, an element that emits blue light having a small y value in the CIE color coordinates is required. In blue, the y value decreases as the spectrum width decreases. By applying the present invention, the y value decreases. An organic EL element that emits blue light with high color purity can be realized.

  In the conventional technology, an organic EL element with high light emission efficiency is realized by setting the distance between the transparent electrode layer and the reflective electrode layer to a predetermined width. However, in the organic EL element 1 of the present embodiment, the distance is By simply defining the width of La, the distance between the surface of the transparent electrode layer 2 on the light emitting layer 4 side and the light emitting surface 4a can be set freely, so that the degree of design freedom is increased as compared with the prior art.

  Hereinafter, the configuration and manufacturing method of the organic EL element 1 will be described more specifically. The layer configuration of the organic EL element 1 can take a layer configuration different from the layer configuration shown in FIG. 1 as long as the distance La satisfies the formula (1) as described above, and is particularly limited to the manufacturing method shown below. Not.

As described above, the organic EL element may have another layer different from the light emitting layer between the reflective electrode layer and the light emitting layer and / or between the light emitting layer and the transparent electrode layer. In addition, a plurality of light emitting layers may be arranged between the reflective electrode layer and the transparent electrode layer without being limited to a single light emitting layer. Specifically, an electron injection layer, an electron transport layer, a hole block layer, a hole injection layer, a hole transport layer, an electron block layer, a buffer layer, and the like are appropriately provided between the reflective electrode layer and the transparent electrode layer. Can be provided.
<Board>
The substrate may be a flexible substrate or a rigid substrate, and those that do not change in the process of manufacturing the organic EL element are suitably used. For example, glass, plastic, polymer film, silicon substrate, and a laminate of these are used. Used. A commercially available substrate can be used as the substrate, and it can be produced by a known method. As described above, in the bottom emission type organic EL element, a transparent substrate is used. Note that a top emission type organic EL element described later may be a transparent substrate or an opaque substrate.
<Transparent electrode layer>
For the transparent electrode layer, a thin film of metal oxide, metal sulfide, metal or the like having high electrical conductivity can be used, and a material having a high light transmittance is preferably used. Specifically, a thin film made of indium oxide, zinc oxide, tin oxide, ITO, indium zinc oxide (abbreviated as IZO), gold, platinum, silver, copper, or the like is used. Among these, ITO, A thin film made of IZO or tin oxide is preferably used. Examples of the method for producing the transparent electrode layer include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Further, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used as the transparent electrode.
<Reflective electrode>
The reflective electrode layer is preferably a thin film made of a material having high light reflectivity, a low work function, easy electron injection into the light emitting layer, and high electrical conductivity. For the reflective electrode, for example, an alkali metal, an alkaline earth metal, a transition metal, a group III-B metal, or the like can be used. Examples of the material of the reflective electrode layer include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium. A metal such as two or more alloys of the metals, one or more of the metals, and one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin Or an alloy thereof, graphite, or a graphite intercalation compound. The thickness of the reflective electrode is appropriately set in consideration of electric conductivity and durability, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

Examples of the method for producing the reflective electrode include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded.
<Hole injection layer>
As the hole injection material constituting the hole injection layer, oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, phenylamine type, starburst type amine type, phthalocyanine type, amorphous carbon, polyaniline, And polythiophene derivatives.

  Examples of the method for forming the hole injection layer include film formation from a solution containing a hole injection material. The solvent used for film formation from a solution is not particularly limited as long as it dissolves the hole injection material. Chlorine solvents such as chloroform, methylene chloride, dichloroethane, ether solvents such as tetrahydrofuran, toluene, xylene And aromatic hydrocarbon solvents such as acetone, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate, and water.

  As a film forming method from a solution, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, a screen printing method, Examples of the application method include a flexographic printing method, an offset printing method, and an ink jet printing method.

The film thickness of the hole injection layer varies depending on the material used, and is set as appropriate so that the drive voltage and light emission efficiency are appropriate. If it is thick, the driving voltage of the element increases, which is not preferable. Therefore, the film thickness of the hole injection layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.
<Light emitting layer>
Although the polymer light emitter composition constituting the light emitting layer is not particularly limited, for example, the number average molecular weight in terms of polystyrene is usually from 10 ³ to 10 ⁸ . The polymer light emitters contained in the polymer light emitter composition may be one kind alone or two or more kinds. The polymer light emitter may be a homopolymer or a copolymer, and may be a conjugated polymer or a nonconjugated polymer, preferably a conjugated polymer.

  The conjugated polymer includes (1) a polymer consisting essentially of a structure in which double bonds and single bonds are arranged alternately, and (2) a structure in which double bonds and single bonds are arranged via nitrogen atoms. (3) a polymer consisting essentially of a structure in which double bonds and single bonds are arranged alternately, a polymer consisting essentially of a structure in which double bonds and single bonds are arranged via nitrogen atoms, etc. In the present specification, specifically, an unsubstituted or substituted fluorenediyl group, an unsubstituted or substituted benzofluorenediyl group, a dibenzofurandiyl group, an unsubstituted or substituted dibenzothiophenediyl group, an unsubstituted Or a substituted carbazolediyl group, an unsubstituted or substituted thiophenediyl group, an unsubstituted or substituted furandyl group, an unsubstituted or substituted pyrroldiyl group, an unsubstituted or substituted benzothiadiazolediyl group, an unsubstituted or substituted One or two or more types selected from the group consisting of an enylene vinylene diyl group, an unsubstituted or substituted thienylene vinylene diyl group, and an unsubstituted or substituted triphenylamine diyl group are used as repeating units, and the repeating units are directly Alternatively, it is a polymer or the like bonded through a linking group.

  In the conjugated polymer, when the repeating units are bonded via a linking group, examples of the linking group include phenylene, biphenylene, naphthalenediyl, anthracenediyl, and the like.

The conjugated polymer, film forming ability, from the viewpoint of solubility in solvents, it is preferred that the number average molecular weight of 10 ³ to 10 approximately ⁸ in terms of polystyrene, among others, 10 ³ number-average molecular weight in terms of polystyrene More preferably, it is about -10 < ⁶ >. It is preferable that the weight average molecular weight in terms of polystyrene is 10 ³ ~1 × 10 ^8, more preferably ^{1 × 10 3 ~1 × 10 6} .

  The conjugated polymer is prepared by synthesizing a monomer having a functional group suitable for the polymerization reaction to be used, and then dissolving the monomer in an organic solvent as necessary. For example, alkali, an appropriate catalyst, a ligand It can synthesize | combine by superposing | polymerizing using well-known polymerization methods, such as aryl coupling.

The polymerization method by aryl coupling is not particularly limited to the method exemplified below. For example, a monomer having a boric acid group or a boric acid ester group and a monomer having a halogen atom such as a bromine atom, an iodine atom or a chlorine atom as a functional group, or a sulfonate group such as a trifluoromethanesulfonate group or a p-toluenesulfonate group. Presence of inorganic bases such as sodium carbonate, potassium carbonate, cesium carbonate, tripotassium phosphate and potassium fluoride, and organic bases such as tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide and tetraethylammonium hydroxide Below, palladium [tetrakis (triphenylphosphine)], [tris (dibenzylideneacetone)] dipalladium, palladium acetate, bis (triphenylphosphine) palladium dichloride, bis (cyclooctadiene) nickele Pd or Ni complex such as triphenylphosphine, tri (2-methylphenyl) phosphine, tri (2-methoxyphenyl) phosphine, diphenylphosphinopropane, tri (cyclohexyl) phosphine, tri (tert- A method of polymerizing by a Suzuki coupling reaction using a catalyst comprising a ligand such as butyl) phosphine, a monomer having a sulfonate group such as a halogen atom or a trifluoromethanesulfonate group, and the like, and bis (cyclooctadiene) nickel Using a catalyst consisting of a nickel zero-valent complex and a ligand such as bipyridyl, or a Ni complex such as [bis (diphenylphosphino) ethane] nickel dichloride or [bis (diphenylphosphino) propane] nickel dichloride, if necessary In addition, a catalyst comprising a ligand such as triphenylphosphine, diphenylphosphinopropane, tri (cyclohexyl) phosphine, tri (tert-butyl) phosphine and a reducing agent such as zinc or magnesium, and dehydrating conditions as necessary A method of polymerizing by a Yamamoto coupling reaction, a compound having a magnesium halide group and a compound having a halogen atom, [bis (diphenylphosphino) ethane] nickel dichloride, [bis (diphenylphosphino) propane] Using Ni catalyst such as nickel dichloride, reacting under dehydrating conditions, polymerizing by aryl coupling reaction, polymerizing by Kumada-Tamao coupling reaction, polymerizing by oxidizing agent such as FeCl ₃ with hydrogen atom as functional group And electrochemical oxidation polymerization methods.

  The reaction solvent is selected in consideration of the polymerization reaction to be used, the solubility of the monomer and polymer, and specifically, tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N- Examples include dimethylformamide, organic solvents such as a mixed solvent of two or more thereof, or a two-phase system of these and water.

  In the Suzuki coupling reaction, an organic solvent such as tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N-dimethylformamide, a mixed solvent of two or more thereof, or with them A two-phase system with water is preferred. In general, the reaction solvent is preferably subjected to deoxygenation treatment in order to suppress side reactions.

  In the Yamamoto coupling reaction, organic solvents such as tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N-dimethylformamide, and a mixed solvent of two or more thereof are preferable. In general, the reaction solvent is preferably subjected to deoxygenation treatment in order to suppress side reactions.

  Among the aryl coupling reactions, the Suzuki coupling reaction and the Yamamoto coupling reaction are preferable from the viewpoint of reactivity, and the Suzuki coupling reaction and the Yamamoto coupling reaction using a nickel zero-valent complex are more preferable. More specifically, with respect to polymerization by Suzuki coupling, see, for example, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 39, 1533-1556 (2001) can be referred to. With respect to polymerization by Yamamoto coupling, for example, known methods described in Macromolecules 1992, 25, 1214-1223 can be referred to.

  The reaction temperature in these reactions is not particularly limited as long as the reaction solution is kept in a liquid state, but the lower limit is preferably −100 ° C., more preferably −20 from the viewpoint of reactivity. The upper limit is preferably 200 ° C., more preferably 150 ° C., and particularly preferably 120 ° C. from the viewpoint of the stability of the compound.

  The conjugated polymer can be taken out according to a known method. For example, the conjugated polymer can be taken out by filtering and drying a precipitate deposited by adding a reaction solution to a lower alcohol such as methanol. When the purity of the obtained conjugated polymer is low, the purity can be increased by purification by ordinary methods such as recrystallization, continuous extraction with a Soxhlet extractor, column chromatography and the like.

  In addition to the polymer light emitter, the polymer light emitter composition used for the light emitting layer may contain other components as long as the charge transport property and the charge injection property are not impaired.

  The light emitting layer is preferably formed by a coating method. The coating method is preferable in that the manufacturing process can be simplified and the productivity is excellent, and the casting method, spin coating method, bar coating method, blade coating method, roll coating method, gravure printing, screen printing, ink jet method, etc. Is mentioned. In the coating method, for example, a liquid composition containing the polymer light emitter, a metal alkoxide, and a coating solvent is prepared as a coating solution, and the coating solution is applied onto a desired layer or electrode and dried. A light emitting layer having a predetermined thickness can be formed.

  As the coating solvent, a stable solvent capable of uniformly dissolving or dispersing the polymer light emitter can be appropriately selected from known solvents and used. Examples of such solvents include alcohols (methanol, ethanol, isopropyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, etc.), organic chlorines (chloroform, 1,2-dichloroethane, etc.), and aromatic hydrocarbons (benzene, Toluene, xylene, etc.), aliphatic hydrocarbons (normal hexane, cyclohexane, etc.), amides (dimethylformamide, etc.), sulfoxides (dimethyl sulfoxide, etc.) and the like. These solvents may be used alone or in combination of two or more.

In addition, for example, a crosslinking agent that is photocrosslinked or thermally crosslinked is added to the coating solution, and after the coating solution is applied, the crosslinking agent is crosslinked to form a light-emitting layer with a desired thickness. Also good.
<Hole transport layer>
As the hole transport material constituting the hole transport layer, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine in a side chain or a main chain, a pyrazoline derivative, an arylamine derivative, a stilbene derivative, Triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) or derivative thereof, or poly (2,5-thienylene vinylene) or Examples thereof include derivatives thereof.

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

  The method for forming the hole transport layer is not particularly limited, but in the case of a low molecular hole transport material, film formation from a mixed solution containing a polymer binder and a hole transport material can be exemplified. Examples of molecular hole transport materials include film formation from a solution containing a hole transport material.

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

  Examples of the film forming method from a solution include the same coating method as the above-described film forming method of the in-hole injection layer.

  As the polymer binder to be mixed, those that do not extremely inhibit charge transport are preferable, and those that weakly absorb visible light are preferably used. For example, polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, poly Examples thereof include vinyl chloride and polysiloxane.

As the film thickness of the hole transport layer, the optimum value varies depending on the material to be used, the drive voltage and the light emission efficiency are appropriately set so as to have an appropriate value, and at least a thickness that does not cause pinholes is required. If the thickness is too thick, the drive voltage of the element becomes high, which is not preferable. Therefore, the film thickness of the hole transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.
<Electron transport layer>
As the electron transport material constituting the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthra Quinodimethane or derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene or derivatives thereof, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof, etc. Can be mentioned.

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

  There are no particular restrictions on the method for forming the electron transport layer, but for low molecular weight electron transport materials, vacuum deposition from powder or film formation from a solution or a molten state can be used. Examples of the material include film formation from a solution or a molten state. In the case of forming a film from a solution or a molten state, a polymer binder may be used in combination. Examples of the method for forming an electron transport layer from a solution include the same film formation method as the method for forming a hole transport layer from a solution described above.

The film thickness of the electron transport layer varies depending on the material used, and is set appropriately so that the drive voltage and the light emission efficiency are appropriate, and at least a thickness that does not cause pinholes is required, and is too thick. In such a case, the driving voltage of the element increases, which is not preferable. Therefore, the film thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.
<Electron injection layer>
As the material constituting the electron injecting layer, an optimum material is appropriately selected according to the type of the light emitting layer, and an alloy containing at least one of alkali metal, alkaline earth metal, alkali metal and alkaline earth metal, alkali A metal or alkaline earth metal oxide, halide, carbonate, or a mixture of these substances can be given. Examples of alkali metals, alkali metal oxides, halides, and carbonates include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride , Rubidium oxide, rubidium fluoride, cesium oxide, cesium fluoride, lithium carbonate, and the like. Examples of alkaline earth metals, alkaline earth metal oxides, halides and carbonates include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, barium oxide, Examples thereof include barium fluoride, strontium oxide, strontium fluoride, and magnesium carbonate. The electron injection layer may be composed of a laminate in which two or more layers are laminated, and examples thereof include LiF / Ca. The electron injection layer is formed by vapor deposition, sputtering, printing, or the like. The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

  FIG. 2 is a front view showing an organic EL element 11 according to another embodiment of the present invention. The organic EL element 1 of the above-described embodiment shown in FIG. 1 is a bottom emission type element, whereas the organic EL element 11 of this embodiment shown in FIG. 2 emits light from the side opposite to the substrate. This is a so-called top emission type element to be taken out.

  The organic EL element 11 of the present embodiment is positioned between the transparent electrode layer 12, the reflective electrode layer 13 disposed to face the transparent electrode layer 12, and the transparent electrode layer 12 and the reflective electrode layer 13. And the light emitting layer 14 to be configured. The distance Lb between the surface (light emitting surface) 14a on the reflective electrode layer 13 side of the light emitting layer 14 and the surface (reflective surface) 13b on the light emitting layer 14 side of the reflective electrode layer 13 is expressed by the following equation (2). Is satisfied.

式（２）において記号「λｏ」は、取出される光のピーク波長を表す。また距離Ｌｂは、好ましくは０.３６７λｏ以上０．４４０以下である。有機ＥＬ素子１１は、透明電極層１２と反射電極層１３との間に、発光層１４とは異なる層を備えていてもよく、また複数の発光層を備えていてもよい。本実施の形態の有機ＥＬ素子１１は、発光層１４と透明電極層１２との間に正孔注入層１６を備え、基板１５の表面上に、反射電極層１３、正孔注入層１６、発光層１４および透明電極層１２がこの順に積層されて構成される。すなわち本実施の形態の有機ＥＬ素子１１は、前述の図１に示す実施の形態の有機ＥＬ素子１における反射電極層と透明電極層との配置を入れ替えた構成である。

In the formula (2), the symbol “λo” represents the peak wavelength of the extracted light. The distance Lb is preferably 0.367λo or more and 0.440 or less. The organic EL element 11 may include a layer different from the light emitting layer 14 between the transparent electrode layer 12 and the reflective electrode layer 13, or may include a plurality of light emitting layers. The organic EL element 11 of the present embodiment includes a hole injection layer 16 between the light emitting layer 14 and the transparent electrode layer 12, and a reflective electrode layer 13, a hole injection layer 16, light emission on the surface of the substrate 15. The layer 14 and the transparent electrode layer 12 are laminated in this order. That is, the organic EL element 11 of the present embodiment has a configuration in which the arrangement of the reflective electrode layer and the transparent electrode layer in the organic EL element 1 of the embodiment shown in FIG.

  Since the organic EL element 11 of the present embodiment emits light on the surface portion of the light emitting layer 14 on the reflective electrode layer 13 side as in the above-described embodiment, the light emitting layer 14 and the hole injection for easy understanding. An explanation will be made by approximating that light emission occurs at the interface (light emitting surface 14a) with the layer 16.

The transparent electrode layer 12 is composed of the above-described members, for example, a thin metal film that is thin enough to transmit light, and as a more specific example, a thin film made of Ca disposed on the light emitting layer 14 side, A laminate with a thin film made of Al laminated on this thin film can be mentioned. The reflective electrode layer 13 is composed of the above-described member, and is composed of, for example, a laminate of a thin film made of Al arranged on the substrate 15 side and a thin film made of MoO ₃ arranged on the light emitting layer 14 side. . Moreover, since the organic EL element 11 of the present embodiment does not extract light from the substrate 15, the substrate 15 may be transparent or opaque.

  Light emitted from the light emitting surface 14a to the transparent electrode layer 12 side (indicated by an arrow B1 in FIG. 2) is sequentially taken out through the light emitting layer 14 and the transparent electrode layer 12. Light emitted from the light emitting surface 4a to the substrate 15 side (indicated by an arrow B2 in FIG. 2) is reflected by the reflecting surface 13b through the hole injection layer 16, and again passes through the hole injection layer 16. The light emitting layer 14 and the transparent electrode layer 12 are sequentially taken out.

  Since the reflected light that makes one round trip between the light emitting surface 14a and the reflecting surface 13b and the light emitted from the light emitting surface 14a to the transparent electrode layer 12 are overlapped, the distance Lb for the same reason as described above. As the length is increased, the emission intensity changes in a vibrational manner. The distance Lb in the present embodiment satisfies the formula (2). The range represented by the expression (2) is a range including only the second shortest distance Lb among the distances that become the maximum point of the emission intensity that changes in vibration when the distance Lb is increased. Therefore, the light emitted from the light emitting surface 4a to the transparent electrode layer 2 side and the reflected light are intensified, and the spectral width is narrowed. Thereby, the organic EL element 11 having both high light intensity and high color purity is realized.

  Similarly to the organic EL element 1 of the above-described embodiment, the organic EL element 11 of the present embodiment only defines the width of the distance Lb, and the surface of the transparent electrode layer 12 on the light-emitting layer 14 side and the light emission. Since the distance from the surface 14a (in this embodiment, the width of the light emitting layer 14) can be set freely, the degree of freedom in design is increased compared to the conventional technique.

  As described above, an electron injection layer, an electron transport layer, or the like may be provided between the reflective electrode layer 13 and the light emitting layer 14 and / or between the light emitting layer 14 and the transparent electrode layer 12. A transparent conductive thin film such as ITO, IZO and tin oxide may be provided between the reflective electrode layer 13 and the light emitting layer 14, and only this transparent conductive thin film is provided between the reflective electrode layer 13 and the light emitting layer 14. The structure provided in is preferable. The organic EL elements 1 and 11 of the above-described embodiments described above have the reflective electrode layer as an anode and the transparent electrode layer as a cathode, but the reflective electrode layer as a cathode and the transparent electrode layer as an anode. When the light is emitted on the transparent electrode layer side of the light emitting layer, an organic EL element satisfying the formula (1) is configured, and when the light is emitted on the reflective electrode layer side of the light emitting layer, the formula (2) What is necessary is just to comprise the organic EL element which satisfy | fills.

  Further, by using the organic EL element of each of the above-described embodiments, a lighting device including the organic EL element or a display device including a plurality of organic EL elements can be realized.

  The organic EL elements of the above-described embodiments can be used as a planar light source, a light source of a segment display device and a dot matrix display device, and a backlight of a liquid crystal display device.

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

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

  Examples of the present invention will be described below, but the present invention is not limited thereto.

  The produced organic EL element is a bottom emission type light emitting element, and is glass substrate / ITO thin film (150 nm) / hole injection layer (50 nm) / light emitting layer / LiF layer (4 nm) / Ca layer (5 nm) / Al layer. (100 nm). The ITO thin film corresponds to a transparent electrode layer, the LiF layer corresponds to a cathode buffer layer, and a laminate of a Ca layer and an Al layer corresponds to a reflective electrode layer. First, a synthesis example in which materials constituting the hole injection layer and the light emitting layer are synthesized will be described. In the following, the number average molecular weight in terms of polystyrene was determined by SEC (Size Exclusion Chromatography). The column used was TOSOH TSKgel SuperHM-H (2) + TSKgel SuperH2000 (4.6 mm I.d. × 15 cm), and the detector was RI (SHIMADZU RID-10A). Tetrahydrofuran (THF) was used as the mobile phase.

(Synthesis Example 1)
<Synthesis of Polymer Compound 1>
N, N′-bis (4-bromophenyl) -N, N′-bis (4-n-butylphenyl) -1,4-phenylenediamine (3.3 g, 4.8 mmol) and 2,2′-bipyridyl (1.9 g, 12 mmol) was dissolved in 132 mL of dehydrated tetrahydrofuran, and the system was purged with nitrogen by bubbling with nitrogen. Under a nitrogen atmosphere, bis (1,5-cyclooctadiene) nickel (0) {Ni (COD) ₂ } (3.3 g, 12 mmol) was added to this solution, and the temperature was raised to 60 ° C. The reaction was allowed for 5 hours. After the reaction, this reaction solution was cooled to room temperature (about 25 ° C.), dropped into a mixed solution of 25% ammonia water 30 mL / methanol 480 mL / ion exchanged water 160 mL and stirred for 1 hour, and then the deposited precipitate was filtered. It was dried under reduced pressure for 2 hours and dissolved in 150 mL of toluene. Thereafter, 120 g of 1N hydrochloric acid was added and stirred for 3 hours, the aqueous layer was removed, 140 mL of 25% aqueous ammonia was added to the organic layer, and the aqueous layer was removed after stirring for 3 hours. The organic layer was washed twice with 600 ml of water. The organic layer was divided into two parts, each was added dropwise to 600 mL of methanol, stirred for 1 hour, the deposited precipitate was filtered and dried under reduced pressure for 2 hours. The yield of the obtained polymer (hereinafter referred to as polymer compound 1) was 3.26 g. The average molecular weight and weight average molecular weight in terms of polystyrene were Mn = 1.6 × 10 ⁴ and Mw = 1.2 × 10 ⁵ , respectively.

不活性雰囲気下、３００ｍｌ三つ口フラスコに１‐ナフタレンボロン酸５．００ｇ（２９ｍｍｏｌ）、２−ブロモベンズアルデヒド６．４６ｇ（３５ｍｍｏｌ）、炭酸カリウム１０.０ｇ（７３ｍｍｏｌ）、トルエン３６ｍｌ、イオン交換水３６ｍｌを入れ、室温で撹拌しつつ２０分間アルゴンバブリングした。続いてテトラキス（トリフェニルホスフィン）パラジウム１６．８ｍｇ（０.１５ｍｍｏｌ）を入れ、さらに室温で撹拌しつつ１０分間アルゴンバブリングした。１００℃に昇温し、２５時間反応させた。室温まで冷却後、トルエンで有機層を抽出、硫酸ナトリウムで乾燥後、溶媒を留去した。トルエン：シクロヘキサン＝１：２混合溶媒を展開溶媒としたシリカゲルカラムで精製することにより、化合物Ａ５.１８ｇ（収率８６％）を白色結晶として得た。
¹Ｈ−ＮＭＲ（３００ＭＨｚ／ＣＤＣｌ₃）：
δ７．３９〜７．６２（ｍ、５Ｈ）、７．７０（ｍ、２Ｈ）、７．９４（ｄ、２Ｈ）、８．１２（ｄｄ、２Ｈ）、９．６３（ｓ、１Ｈ）
ＭＳ（ＡＰＣＩ（＋））：（Ｍ＋Ｈ）⁺ ２３３ Synthesis example 2
(Synthesis of Compound A)

Under an inert atmosphere, in a 300 ml three-necked flask, 5.00 g (29 mmol) of 1-naphthaleneboronic acid, 6.46 g (35 mmol) of 2-bromobenzaldehyde, 10.0 g (73 mmol) of potassium carbonate, 36 ml of toluene, 36 ml of ion-exchanged water And argon bubbling was performed for 20 minutes with stirring at room temperature. Subsequently, 16.8 mg (0.15 mmol) of tetrakis (triphenylphosphine) palladium was added, and argon was bubbled for 10 minutes while stirring at room temperature. The temperature was raised to 100 ° C. and reacted for 25 hours. After cooling to room temperature, the organic layer was extracted with toluene, dried over sodium sulfate, and the solvent was distilled off. Purification by a silica gel column using a toluene: cyclohexane = 1: 2 mixed solvent as a developing solvent gave 5.18 g (yield 86%) of Compound A as white crystals.
¹ H-NMR (300 MHz / CDCl ₃ ):
δ 7.39-7.62 (m, 5H), 7.70 (m, 2H), 7.94 (d, 2H), 8.12 (dd, 2H), 9.63 (s, 1H)
MS (APCI (+)): (M + H) ^<+> 233

不活性雰囲気下で３００ｍｌの三つ口フラスコに化合物Ａ８．００ｇ（３４.４ｍｍｏｌ）と脱水したテトラヒドロフラン（ＴＨＦ）４６ｍｌを入れ、−７８℃まで冷却した。
続いてｎ−オクチルマグネシウムブロミド（１.０ｍｏｌ／ｌＴＨＦ溶液）５２ｍｌを３０分かけて滴下した。滴下終了後０℃まで昇温し、１時間撹拌後、室温まで昇温して４５分間撹拌した。氷浴して１Ｎ塩酸２０ｍｌを加えて反応を終了させ、酢酸エチルで有機層を抽出、硫酸ナトリウムで乾燥した。溶媒を留去した後トルエン：ヘキサン＝１０：１混合溶媒を展開溶媒とするシリカゲルカラムで精製することにより、化合物Ｂ７．６４ｇ（収率６４％）を淡黄色のオイルとして得た。ＨＰＬＣ測定では２本のピークが見られたが、ＬＣ−ＭＳ測定では同一の質量数であることから、異性体の混合物であると判断した。 Synthesis example 3
(Synthesis of Compound B)

Under an inert atmosphere, 8.00 g (34.4 mmol) of Compound A and 46 ml of dehydrated tetrahydrofuran (THF) were placed in a 300 ml three-necked flask and cooled to -78 ° C.
Subsequently, 52 ml of n-octylmagnesium bromide (1.0 mol / l THF solution) was added dropwise over 30 minutes. After completion of dropping, the temperature was raised to 0 ° C., stirred for 1 hour, then warmed to room temperature and stirred for 45 minutes. The reaction was terminated by adding 20 ml of 1N hydrochloric acid in an ice bath, and the organic layer was extracted with ethyl acetate and dried over sodium sulfate. After distilling off the solvent, the residue was purified by a silica gel column using a mixed solvent of toluene: hexane = 10: 1 as a developing solvent to obtain 7.64 g (yield: 64%) of Compound B as a pale yellow oil. Although two peaks were observed in the HPLC measurement, they were judged to be a mixture of isomers because they were the same mass number in the LC-MS measurement.

不活性雰囲気下、５００ｍｌ三つ口フラスコに化合物Ｂ（異性体の混合物）５.００ｇ（１４.４ｍｍｏｌ）と脱水ジクロロメタン７４ｍｌを入れ、室温で撹拌、溶解させた。
続いて、三フッ化ホウ素のエーテラート錯体を室温で１時間かけて滴下し、滴下終了後室温で４時間撹拌した。撹拌しながらエタノール１２５ｍｌをゆっくりと加え、発熱がおさまったらクロロホルムで有機層を抽出、２回水洗し、硫酸マグネシウムで乾燥した。溶媒を留去後、ヘキサンを展開溶媒とするシリカゲルカラムで精製することにより、化合物Ｃの３．２２ｇ（収率６８％）を無色のオイルとして得た。
¹Ｈ−ＮＭＲ（３００ＭＨｚ／ＣＤＣｌ₃）：
δ０．９０（ｔ、３Ｈ）、１．０３〜１．２６（ｍ、１４Ｈ）、２．１３（ｍ、２Ｈ）、４．０５（ｔ、１Ｈ）、７．３５（ｄｄ、１Ｈ）、７．４６〜７．５０（ｍ、２Ｈ）、７．５９〜７．６５（ｍ、３Ｈ）、７．８２（ｄ、１Ｈ）、７．９４（ｄ、１Ｈ）、８．３５（ｄ、１Ｈ）、８．７５（ｄ、１Ｈ）
ＭＳ（ＡＰＣＩ（＋））：（Ｍ＋Ｈ）⁺ ３２９ Synthesis example 4
(Synthesis of Compound C)

Under an inert atmosphere, 5.00 g (14.4 mmol) of Compound B (mixture of isomers) and 74 ml of dehydrated dichloromethane were placed in a 500 ml three-necked flask and stirred and dissolved at room temperature.
Subsequently, an etherate complex of boron trifluoride was added dropwise at room temperature over 1 hour, and after completion of the addition, the mixture was stirred at room temperature for 4 hours. While stirring, 125 ml of ethanol was slowly added. When the exotherm subsided, the organic layer was extracted with chloroform, washed twice with water, and dried over magnesium sulfate. After distilling off the solvent, the residue was purified by a silica gel column using hexane as a developing solvent to obtain 3.22 g (yield 68%) of Compound C as a colorless oil.
¹ H-NMR (300 MHz / CDCl ₃ ):
δ 0.90 (t, 3H), 1.03-1.26 (m, 14H), 2.13 (m, 2H), 4.05 (t, 1H), 7.35 (dd, 1H), 7 .46-7.50 (m, 2H), 7.59-7.65 (m, 3H), 7.82 (d, 1H), 7.94 (d, 1H), 8.35 (d, 1H) ), 8.75 (d, 1H)
MS (APCI (+)): (M + H) ^<+> 329

不活性雰囲気下２００ｍｌ三つ口フラスコにイオン交換水２０ｍｌをいれ、撹拌しながら水酸化ナトリウム１８．９ｇ（０.４７ｍｏｌ）を少量ずつ加え、溶解させた。水溶液が室温まで冷却した後、トルエン２０ｍｌ、化合物Ｃ５.１７ｇ（１５.７ｍｍｏｌ）、臭化トリブチルアンモニウム１．５２ｇ（４.７２ｍｍｏｌ）を加え、５０℃に昇温した。
臭化ｎ−オクチルを滴下し、滴下終了後５０℃で９時間反応させた。反応終了後トルエンで有機層を抽出し、２回水洗し、硫酸ナトリウムで乾燥した。ヘキサンを展開溶媒とするシリカゲルカラムで精製することにより、化合物Ｄの５．１３ｇ（収率７４％）を黄色のオイルとして得た。
¹Ｈ−ＮＭＲ（３００ＭＨｚ／ＣＤＣｌ₃）：
δ０．５２（ｍ、２Ｈ）、０．７９（ｔ、６Ｈ）、１．００〜１．２０（ｍ、２２Ｈ）、２．０５（ｔ、４Ｈ）、７．３４（ｄ、１Ｈ）、７．４０〜７．５３（ｍ、２Ｈ）、７．６３（ｍ、３Ｈ）、７．８３（ｄ、１Ｈ）、７．９４（ｄ、１Ｈ）、８．３１（ｄ、１Ｈ）、８．７５（ｄ、１Ｈ）
ＭＳ（ＡＰＣＩ（＋））：（Ｍ＋Ｈ）⁺ ４４１ Synthesis example 5
(Synthesis of Compound D)

Under an inert atmosphere, 20 ml of ion-exchanged water was placed in a 200 ml three-necked flask, and 18.9 g (0.47 mol) of sodium hydroxide was added little by little with stirring to dissolve. After the aqueous solution was cooled to room temperature, 20 ml of toluene, 5.17 g (15.7 mmol) of Compound C and 1.52 g (4.72 mmol) of tributylammonium bromide were added, and the temperature was raised to 50 ° C.
N-Octyl bromide was added dropwise, and after completion of the addition, the mixture was reacted at 50 ° C. for 9 hours. After completion of the reaction, the organic layer was extracted with toluene, washed twice with water, and dried over sodium sulfate. By purifying with a silica gel column using hexane as a developing solvent, 5.13 g (yield 74%) of Compound D was obtained as a yellow oil.
¹ H-NMR (300 MHz / CDCl ₃ ):
δ 0.52 (m, 2H), 0.79 (t, 6H), 1.00-1.20 (m, 22H), 2.05 (t, 4H), 7.34 (d, 1H), 7 40 to 7.53 (m, 2H), 7.63 (m, 3H), 7.83 (d, 1H), 7.94 (d, 1H), 8.31 (d, 1H), 8. 75 (d, 1H)
MS (APCI (+)): (M + H) ^<+> 441

空気雰囲気下、５０ｍｌの三つ口フラスコに化合物Ｄ４．００ｇ（９．０８ｍｍｏｌ）と酢酸：ジクロロメタン＝１：１混合溶媒５７ｍｌを入れ、室温で撹拌、溶解させた。続いて三臭化ベンジルトリメチルアンモニウム７．７９ｇ（２０．０ｍｍｏｌ）を加えて撹拌しつつ、塩化亜鉛を三臭化ベンジルトリメチルアンモニウムが完溶するまで加えた。室温で２０時間撹拌後、５％亜硫酸水素ナトリウム水溶液１０ｍｌを加えて反応を停止し、クロロホルムで有機層を抽出、炭酸カリウム水溶液で２回洗浄し、硫酸ナトリウムで乾燥した。ヘキサンを展開溶媒とするフラッシュカラムで２回精製した後、エタノール：ヘキサン＝１：１、続いて１０：１混合溶媒で再結晶することにより、化合物Ｅの４．１３ｇ（収率７６％）を白色結晶として得た。
¹Ｈ−ＮＭＲ（３００ＭＨｚ／ＣＤＣｌ₃）：
δ０．６０（ｍ、２Ｈ）、０．９１（ｔ、６Ｈ）、１．０１〜１．３８（ｍ、２２Ｈ）、２．０９（ｔ、４Ｈ）、７．６２〜７．７５（ｍ、３Ｈ）、７．８９（ｓ、１Ｈ）、８．２０（ｄ、１Ｈ）、８．４７（ｄ、１Ｈ）、８．７２（ｄ、１Ｈ）
ＭＳ（ＡＰＰＩ（＋））：（Ｍ＋Ｈ）⁺ ５９８
合成例７
＜高分子化合物２の合成＞
化合物Ｅ２２．５ｇと２，２’−ビピリジル１７．６ｇとを反応容器に仕込んだ後、反応系内を窒素ガスで置換した。これに、あらかじめアルゴンガスでバブリングして、脱気したテトラヒドロフラン（脱水溶媒）１５００ｇを加えた。次に、この混合溶液に、ビス（１，５−シクロオクタジエン）ニッケル（０）を３１ｇ加え、室温で１０分間攪拌した後、６０℃で３時間反応した。なお、反応は、窒素ガス雰囲気中で行った。 Synthesis Example 6
(Synthesis of Compound E)

Under an air atmosphere, 4.00 g (9.08 mmol) of Compound D and 57 ml of a mixed solvent of acetic acid: dichloromethane = 1: 1 were placed in a 50 ml three-necked flask, and the mixture was stirred and dissolved at room temperature. Subsequently, 7.79 g (20.0 mmol) of benzyltrimethylammonium tribromide was added and stirred, and zinc chloride was added until benzyltribromide tribromide was completely dissolved. After stirring at room temperature for 20 hours, the reaction was stopped by adding 10 ml of 5% aqueous sodium bisulfite solution, and the organic layer was extracted with chloroform, washed twice with aqueous potassium carbonate solution, and dried over sodium sulfate. After purification twice with a flash column using hexane as a developing solvent, 4.13 g (76% yield) of Compound E was obtained by recrystallization with ethanol: hexane = 1: 1, followed by a 10: 1 mixed solvent. Obtained as white crystals.
¹ H-NMR (300 MHz / CDCl ₃ ):
δ 0.60 (m, 2H), 0.91 (t, 6H), 1.01-1.38 (m, 22H), 2.09 (t, 4H), 7.62-7.75 (m, 3H), 7.89 (s, 1H), 8.20 (d, 1H), 8.47 (d, 1H), 8.72 (d, 1H)
MS (APPI (+)): (M + H) ^<+> 598
Synthesis example 7
<Synthesis of Polymer Compound 2>
After charging 22.5 g of compound E and 17.6 g of 2,2′-bipyridyl in a reaction vessel, the inside of the reaction system was replaced with nitrogen gas. To this, 1500 g of tetrahydrofuran (dehydrated solvent) deaerated previously by bubbling with argon gas was added. Next, 31 g of bis (1,5-cyclooctadiene) nickel (0) was added to this mixed solution, and the mixture was stirred at room temperature for 10 minutes and then reacted at 60 ° C. for 3 hours. The reaction was performed in a nitrogen gas atmosphere.

  After the reaction, this reaction solution was cooled, and then a mixed solution of 25% aqueous ammonia 200 ml / methanol 900 ml / ion exchanged water 900 ml was poured into this solution and stirred for about 1 hour. Next, the produced precipitate was filtered and collected. This precipitate was dried under reduced pressure and then dissolved in toluene. The toluene solution was filtered to remove insoluble matters, and the toluene solution was purified by passing through a column packed with alumina. Next, this toluene solution was washed with a 1N aqueous hydrochloric acid solution, allowed to stand and separated, and then the toluene solution was recovered. Next, this toluene solution was washed with about 3% aqueous ammonia, allowed to stand and separated, and then the toluene solution was recovered. Next, this toluene solution was washed with ion-exchanged water, allowed to stand and separated, and then the toluene solution was recovered. Next, this toluene solution was poured into methanol and re-precipitated.

Next, the produced precipitate was recovered, washed with methanol, and then dried under reduced pressure to obtain 6.0 g of a polymer. This polymer is referred to as polymer compound 2. The obtained polymer compound 2 had a polystyrene-reduced weight average molecular weight of 8.2 × 10 ⁵ and a number average molecular weight of 1.0 × 10 ⁵ .

<Creation of hole injection layer>
Polymer compound 1 and crosslinking agent DPHA (dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd., trade name: KAYARAD DPHA) were mixed and dissolved in toluene at a ratio of 80/20 (weight ratio). Then, it filtered with the 0.2 micron diameter Teflon (trademark) filter, and prepared the coating solution. The above solution was formed by spin coating on a glass substrate with an ITO film having a thickness of 150 nm formed by sputtering, and baked at 300 ° C. for 20 minutes in a nitrogen atmosphere to produce a hole injection layer. The film thickness of the hole injection layer after the baking treatment was measured with a stylus type film thickness meter (manufactured by Beco, trade name: DEKTAK), and was about 50 nm.
<Preparation of solution composition for light emitting layer>
Polymer compound 2 was added to chlorobenzene at 0.5 wt%, and DCBP: 4,4′-bis (9-carbazoyl) -biphenyl (manufactured by Dojindo Laboratories Co., Ltd.) as an additive was added to polymer compound 2. The mixture was mixed and dissolved at a ratio of 160% by weight. Thereafter, the solution was filtered through a 0.2 micron diameter Teflon (registered trademark) filter to prepare a coating solution.

＜素子の作成及び評価＞
正孔注入層の上に前記発光層用溶液を用いてスピンコートにより発光層を成膜した。さらに、これを減圧下９０℃で１時間乾燥した後、陰極バッファー層としてフッ化リチウムを４ｎｍ、陰極としてカルシウムを５ｎｍ、次いでアルミニウムを１００ｎｍ蒸着して、高分子発光素子を作製した。蒸着のときの真空度は、すべて１×１０^-4Ｐａ〜９×１０^-4Ｐａであった。

<Creation and evaluation of element>
A light emitting layer was formed on the hole injection layer by spin coating using the solution for light emitting layer. Further, this was dried at 90 ° C. under reduced pressure for 1 hour, and then lithium fluoride was deposited at 4 nm as a cathode buffer layer, calcium was deposited at 5 nm as a cathode, and then aluminum was deposited at 100 nm to produce a polymer light emitting device. The degree of vacuum in vapor deposition were all ^{1 × 10 -4 Pa~9 × 10 -4} Pa.

Eight organic EL elements differing only in the thickness of the light emitting layer were prepared as described above. The light emitting part of each organic EL element was 2 mm × 2 mm (area 4 mm ² ). A voltage was applied to each organic EL element while changing the voltage stepwise, and the front luminance of EL light emitted from each organic EL element was measured. The value of external quantum efficiency was obtained from the measured value assuming Lambasian as the emission distribution. Since the peak wavelength λo of the extracted light is 450 nm, the minimum value of the distance La shown in Equation (1) is about 177 nm, and the maximum value is about 245 nm. Accordingly, among the produced organic EL elements, three organic EL elements having a light emitting layer thickness of 195 nm, 205 nm, and 232 nm satisfy Expression (1).

  Table 1 shows the maximum external quantum efficiency, full width at half maximum of EL emission, and chromaticity coordinates of the obtained device. FIG. 3 is a graph showing the maximum external quantum efficiency and full width at half maximum with respect to the thickness of the light emitting layer. In FIG. 3, the maximum external quantum efficiency is indicated by a solid line, the value is indicated by the left vertical axis, the full width at half maximum of the spectrum is indicated by a broken line, and the value is indicated by the right vertical axis.

  As shown in Table 1 and FIG. 3, when the thickness of the light emitting layer was 195 nm, 205 nm, and 232 nm, the full width at half maximum of the spectrum was narrow, blue light emission with high color purity was obtained, and the light emission efficiency was high.

  Next, with respect to the top emission type organic EL element, the change in the emission intensity and the full width at half maximum of the spectrum when the distance Lb was changed was analyzed using a time domain difference method (FDTD). Here, the peak intensity of the spectrum obtained by calculation was taken as the emission intensity.

  First, a top emission type organic EL element emitting blue light was analyzed. Materials for the hole transport layer (HT12) and the blue light emitting layer (BP371) were obtained from Summation. The element structure used as an analysis model is substrate / Al layer (100 nm) / PEDOT layer / HT12 layer (20 nm) / BP371 layer (60 nm) / Al layer (5 nm). In the analysis, the layer thickness of the layers other than the PEDOT layer was fixed, and only the film thickness of the PEDOT layer was changed to examine the characteristics of the extracted light when the distance Lb was changed. In addition, light is emitted at the interface between the BP371 layer corresponding to the light emitting layer and the HT12 layer. The spectrum of light generated at the interface was the same as the PL (photoluminescence) spectrum of the light emitting layer film. Since the peak wavelength λo of the extracted light is 460 nm, the minimum value of the distance Lb shown in Expression (2) is 144 nm, and the maximum value is 210 nm. Therefore, an organic EL element having a thickness of the PEDOT layer in the range of 122 nm or more and 190 nm or less satisfies the formula (2). The analysis results are shown in FIG. In FIG. 4, the peak intensity is indicated by a solid line, the value is indicated by the right vertical axis, and the difference in full width at half maximum from the reference width is indicated by a broken line with reference to the PL spectrum of the light emitting layer film. The vertical axis represents the value.

  As shown in FIG. 4, it was confirmed that an organic EL device having both high light intensity and high color purity can be realized by satisfying the formula (2).

  Next, a top emission type organic EL element that emits green light was analyzed. The material of the green light emitting layer (GP1300) was obtained from Summation. The element structure used as an analysis model is substrate Al (100 nm) / PEDOT layer / HT12 layer (20 nm) / GP1300 layer (80 nm) / Al layer (5 nm). In the analysis, the thickness of the layers other than the PEDOT layer was fixed, and only the film thickness of the PEDOT layer was changed to examine the characteristics of the light extracted when the distance Lb was changed. Further, light is emitted at the interface between the GP1300 layer corresponding to the light emitting layer and the HT12 layer. The spectrum of light generated at the interface was the same as the PL spectrum of the light emitting layer film. Since the peak wavelength λo of the extracted light is 545 nm, the minimum value of the distance Lb shown in Expression (2) is 171 nm, and the maximum value is 249 nm. Therefore, an organic EL element having a thickness of the PEDOT layer in the range of 151 nm or more and 229 nm or less satisfies the formula (2). The analysis results are shown in FIG. In FIG. 5, the peak intensity is indicated by a solid line, the value is indicated by the right vertical axis, the difference of the full width at half maximum from the reference width is indicated by a broken line with reference to the PL spectrum of the light emitting layer film, and the left The vertical axis indicates the value.

  As shown in FIG. 5, it was confirmed that an organic EL device having both high light intensity and high color purity can be realized by satisfying the formula (2).

It is a front view which shows the organic EL element 1 of one Embodiment of this invention. It is a front view which shows the organic EL element 11 of other embodiment of this invention. It is a graph which shows the maximum external quantum efficiency with respect to the layer thickness of a light emitting layer, and a half value full width. It is a graph which shows the maximum external quantum efficiency with respect to the layer thickness of a PEDOT layer, and a full width at half maximum. It is a graph which shows the maximum external quantum efficiency with respect to the layer thickness of a PEDOT layer, and a full width at half maximum.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Organic EL element 2,12 Transparent electrode layer 3,13 Reflective electrode layer 3b, 13b Reflective surface 4,14 Light emitting layer 4a, 4b Light emitting surface 5,15 Substrate 6,16 Hole injection layer

Claims (4)

A transparent electrode layer;
A reflective electrode layer disposed to face the transparent electrode layer;
A light emitting layer located between the transparent electrode layer and the reflective electrode layer,
A distance La between the surface of the light emitting layer on the transparent electrode layer side and the surface of the reflective electrode layer on the light emitting layer side satisfies the following formula (1).

(In formula (1), the symbol “λo” represents the peak wavelength of the extracted light.) A transparent electrode layer;
A reflective electrode layer disposed to face the transparent electrode layer;
A light emitting layer located between the transparent electrode layer and the reflective electrode layer,
A distance Lb between a surface of the light emitting layer on the reflective electrode layer side and a surface of the reflective electrode layer on the light emitting layer side satisfies the following formula (2).

(In formula (2), the symbol “λo” represents the peak wavelength of the extracted light.)   A lighting device comprising the organic electroluminescence element according to claim 1.   A display device comprising a plurality of the organic electroluminescence elements according to claim 1.

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