JP2014120334A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element having excellent power efficiency, a long light emission life, and toning aptitude, and capable of obtaining excellent light distribution characteristics (viewing angle dependency).SOLUTION: Each of organic electroluminescent elements 100 and 200 comprises: at least two light emitting units 3; and intermediate electrode layers 4 arranged between the light emitting units 3. The light emitting units 3 and the intermediate electrode layers 4 are arranged between a pair of main electrodes 2 and 6 one of which is a transparent electrode. The light emitting units 3 include a plurality of organic functional layers, including luminous layers. At least one of the intermediate electrode layers 4 is a conductive layer containing silver as a primary component. Among the luminous layers, a light emitting unit 3 which emits light having the shortest wavelength is arranged at the farthest position away from the transparent electrode at a main light emitting side of the organic electroluminescent element.

Description

  The present invention relates to an organic electroluminescence element. More specifically, the present invention relates to an organic electroluminescence device with improved viewing angle dependency.

  As a light-emitting electronic display device, there is an electroluminescence display (ELD). As a component of ELD, an inorganic electroluminescence element and an organic electroluminescence element (hereinafter also referred to as “organic EL element”) can be given. Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL element has a configuration in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are injected by injecting electrons and holes into the light emitting layer and recombining them. This is an element that emits light by utilizing light (fluorescence or phosphorescence) emitted when excitons are deactivated. As the performance of the organic EL element, it is possible to emit light at a voltage of about several V to several tens V, and since it is a self-luminous type, it has a wide viewing angle and high visibility. In addition, since the organic EL element is a thin-film type complete solid-state element, it has attracted attention from the viewpoints of space saving and portability. In addition, in order to make full use of the characteristics of a completely solid element, it has been studied to produce a flexible element from a rigid substrate to a flexible plastic or metal foil.

  Another major feature of the organic EL element is that it is a surface light source, unlike main light sources that have been practically used, such as light-emitting diodes and cold-cathode tubes. Applications that can effectively utilize this characteristic include illumination light sources and various display backlights. In particular, it is also suitable to be used as a backlight of a liquid crystal full color display whose demand has been increasing in recent years.

  Compared to conventional devices that can emit only a single color, the use of organic EL devices that can control the color tone and white color temperature for lighting enables new value creation, and research continues ( For example, see Patent Documents 1 and 2.) However, in the color tone control methods by these disclosed methods, the viewing angle dependency is difficult due to the increase in the thickness of the organic functional layer and the presence of intermediate electrodes with different refractive indexes sandwiched therebetween. There was a problem. Regarding viewing angle dependence, a method of providing a smooth particle layer between a substrate and an electrode is disclosed as a technique for efficiently extracting light in a useful mode of an organic EL element (see, for example, Patent Document 3). ). However, even with these techniques, sufficient light distribution cannot be obtained, and there is still a problem with respect to viewing angle dependency.

On the other hand, as a method for achieving both light emission efficiency and driving life that are in a trade-off relationship, an organic functional layer including a light emitting layer composed of an organic material is used as a single light emitting unit, and a plurality of light emission is performed through an intermediate electrode layer. An organic electroluminescence element having a so-called tandem structure has been proposed in which the units are stacked to achieve a long life while ensuring luminous efficiency. For example, Patent Document 4 discloses a configuration in which a conductive layer containing magnesium (Mg) as a main component and containing silver (Ag) is used in a floating state. Patent Document 5 discloses a metal layer having a small work function such as Mg, Mg / Ag, and arsenic (As), indium tin oxide (SnO ₂ —In ₂ O ₃ : Indium Tin Oxide: ITO), The structure which uses this laminated body as an intermediate electrode is disclosed. In Patent Document 6, a transparent conductive film such as ITO is used as an intermediate electrode, and in the electroluminescent layer (organic functional layer), a layer closest to the previous intermediate electrode is hardly etched with a benzoxazole derivative or a pyridine derivative. An arrangement using materials is disclosed.
However, with these disclosed methods, it is difficult to obtain sufficient luminous efficiency and lifetime characteristics sufficient for practical use.

JP 2009-146860 A International Publication No. 2007/083918 JP 2012-79515 A US Pat. No. 6,337,492 Japanese Patent No. 3496681 JP-A-2005-340187

  The present invention has been made in view of the above-described problems and circumstances, and the solution is to have excellent power efficiency and light emission lifetime, toning suitability, and excellent light distribution characteristics (viewing angle dependency). It is to provide an organic electroluminescent device capable of the above.

  In order to solve the above problems, the present inventor examined the cause of the above problems and the like. As a result, at least two light emitting units are disposed between a pair of main electrodes, one of which is a transparent electrode, and the light emitting units. In the organic electroluminescence device including the intermediate electrode layer, the intermediate electrode layer is a conductive layer containing silver as a main component, and is arranged appropriately for a specific light-emitting unit, so that power efficiency and light emission are achieved. The present inventors have found that an organic electroluminescence element having a long life, having a color matching property, and excellent light distribution characteristics (viewing angle dependency) can be realized.

That is, the said subject which concerns on this invention is solved by the following means.
1. An organic electroluminescent device comprising at least two light emitting units and an intermediate electrode layer disposed between the light emitting units between a pair of main electrodes, each of which is a transparent electrode,
(1) The light emitting unit has a plurality of organic functional layers including a light emitting layer,
(2) Among the intermediate electrode layers, at least one intermediate electrode layer is a conductive layer containing silver as a main component,
(3) Among the light emitting layers, a light emitting unit that emits light having the shortest wavelength is disposed at a position farthest from the transparent electrode on the main light emitting side of the organic electroluminescence element. Luminescence element.

  2. 2. The organic electroluminescence device according to item 1, wherein the intermediate electrode layer has a thickness of 3 to 20 nm.

3. The plurality of light emitting units have at least one light emitting layer among a blue light emitting layer that emits blue light, a green light emitting layer that emits green light, and a red light emitting layer that emits red light,
3. The organic electroluminescent element according to claim 1, wherein the light emitting unit that emits green light is disposed at a position closest to the transparent electrode on the light emitting side.

  4). The light emitting unit that emits light having the longest wavelength among the light emitting units is disposed between two intermediate electrode layers, according to any one of the first to third aspects. Organic electroluminescence device.

  5. The total thickness of the plurality of organic functional layers constituting the light emitting unit is within the range of the number of light emitting units × (100 to 200) nm, any one of items 1 to 4 The organic electroluminescent element of description.

〔ただし一般式（１）中、Ｙ_１は、アリーレン基、ヘテロアリーレン基又はそれらの組み合わせからなる２価の連結基を表す。Ｅ_１〜Ｅ_３４は、各々−Ｃ（Ｒ_１）＝又は−Ｎ＝を表し、Ｒ_１は水素原子又は置換基を表す。Ｅ_１７〜Ｅ_２５の少なくとも一つ及びＥ_２６〜Ｅ_３４の少なくとも一つは−Ｎ＝を表す。ｋ１及びｋ２は０〜４の整数を表すが、ｋ１＋ｋ２は２以上の整数である。一般式（２）中、Ｅ_１、Ｅ_２のうち少なくとも一つは窒素原子であり、Ｅ_６〜Ｅ_１０のうち少なくとも一つは窒素原子であり、Ｅ_１１〜Ｅ_１５のうち少なくとも一つは窒素原子である。Ｒ_１は置換基を表す。〕 6). The organic according to any one of Items 1 to 5, wherein the intermediate electrode layer has an underlayer containing a compound represented by the following general formula (1) or (2): Electroluminescence element.

[In General Formula (1), Y ₁ represents a divalent linking group composed of an arylene group, a heteroarylene group, or a combination thereof. E _{1 to} E ₃₄ each represent —C (R ₁ ) ═ or —N═, and R ₁ represents a hydrogen atom or a substituent. At least one of E _{17 to} E ₂₅ and at least one of E _{26 to} E ₃₄ represent -N =. k1 and k2 represent an integer of 0 to 4, and k1 + k2 is an integer of 2 or more. In general formula (2), at least one of E ₁ and E ₂ is a nitrogen atom, at least one of E _{6 to} E ₁₀ is a nitrogen atom, and at least one of E _{11 to} E ₁₅ is Nitrogen atom. R ₁ represents a substituent. ]

7). Each of the plurality of light emitting units has a hole transport layer as an organic functional layer, and
The layer thickness of the hole transport layer included in the other light-emitting unit is greater than the thickness of the hole transport layer included in the light-emitting unit disposed in the position closest to the transparent electrode on the light emitting side by 20 nm or more. The organic electroluminescent element according to any one of items 1 to 6, wherein:

  8). The organic electroluminescent element according to any one of claims 1 to 7, wherein one of the pair of main electrodes is a transparent electrode that functions as an anode.

By the above means of the present invention, it is possible to provide an organic electroluminescence device that is excellent in power efficiency and light emission lifetime, has toning suitability, and can obtain excellent light distribution characteristics (viewing angle dependency).
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

That is, since the intermediate electrode layer contains silver as a main component, the optical constant of the intermediate electrode layer is represented by ITO as the optical constant of the charge generation layer composed only of organic substances and metal salts in the entire device and the intermediate electrode layer. This is greatly different from the optical constant of the metal oxide. For this reason, it is speculated that the optical behavior is different by using silver as the main component of the intermediate electrode layer as compared with the case where a metal oxide typified by ITO is used as the intermediate electrode layer.
The present inventor Chutinan et al. (A. Chutinan, K. Ishihara, T. Asano, M. Fujita, and S. Noda, "Theoretical Analysis and Light-Effects of Tightness". Organic Electronics, vol. 6, pp. 3-9 (2005)), the light of an organic EL element having a structure in which a light emitting unit as in the present invention is separated by an intermediate electrode layer mainly composed of silver. As a result of simulating the distribution of the light distribution characteristics when the light emitting unit that emits light with the shortest wavelength is arranged farthest from the transparent electrode It was found that an organic EL element excellent in the above can be produced.
The intermediate electrode layer of the present invention has a base layer, and a conductive layer containing silver as a main component is formed adjacent to the base layer in the intermediate electrode layer. In addition, the base layer contains a compound having an atom having affinity for silver atoms (hereinafter referred to as “silver affinity compound”). The silver affinity compound is a nitrogen-containing aromatic compound, and has a high electron transport ability and can be suitably used as an electron transport material.
Thus, when the conductive layer is formed on the intermediate electrode layer adjacent to the base layer, the silver atoms constituting the conductive layer of the intermediate electrode layer are combined with the silver affinity compound contained in the base layer. By interacting, the diffusion distance of silver atoms on the surface of the underlayer is reduced, and aggregation of silver at a specific location is suppressed.
That is, the silver atoms first form a two-dimensional nucleus on the surface of the underlayer containing a compound having an atom having an affinity for silver atoms, and form a two-dimensional single crystal layer around it. The film is formed by growth-type (Frank-van der Merwe: FM type) film growth.
In general, an island-shaped growth type (Volume-Weber) in which silver atoms attached on the surface of the underlayer are bonded while diffusing the surface to form a three-dimensional nucleus and grow into a three-dimensional island shape. : VW type) is considered to be easily formed into islands by film growth, but in the present invention, the silver-affinity compound contained in the underlayer prevents such a mode of island growth, It is assumed that layer growth is promoted.
Accordingly, a conductive layer having a uniform layer thickness can be obtained even though the layer thickness is thin. As a result, it is possible to realize an organic electroluminescence element having an intermediate electrode layer with ensured conductivity while maintaining light transmittance with a thinner layer thickness.

Schematic sectional view showing an example of a configuration of an organic electroluminescence element having two light emitting units Schematic sectional view showing an example of a configuration of an organic electroluminescence element having three light emitting units

  The organic electroluminescence device of the present invention comprises an organic electroluminescence device comprising at least two light emitting units and an intermediate electrode layer disposed between the light emitting units between a pair of main electrodes, one of which is a transparent electrode (1) The light emitting unit has a plurality of organic functional layers including a light emitting layer, and (2) at least one of the intermediate electrode layers contains silver as a main component. (3) Among the light emitting layers, the light emitting unit that emits the light having the shortest wavelength is disposed at a position farthest from the transparent electrode on the main light emitting side of the organic electroluminescence element. It is characterized by. This feature is a technical feature common to the inventions according to claims 1 to 8.

  As an embodiment of the present invention, it is preferable that the thickness of the intermediate electrode layer is in the range of 3 to 20 nm in that the effects of the present invention can be further exhibited. Thereby, the absorption component or reflection component of the layer is kept low, and the light transmittance is maintained. Also, conductivity is ensured.

  In the present invention, the plurality of light emitting units have at least one light emitting layer among a blue light emitting layer that emits blue light, a green light emitting layer that emits green light, and a red light emitting layer that emits red light. The light emitting unit that emits green light is preferably disposed at a position closest to the transparent electrode on the light emitting side. Although the mechanism of effect expression by this is not clearly understood, it has been confirmed by experiments that it has an effect.

  Moreover, in this invention, it is preferable that the light emitting unit which light-emits light with the longest wavelength among the said light emitting units is arrange | positioned between two intermediate electrode layers. Although the mechanism of effect expression by this is not clearly understood, it has been confirmed by experiments that it has an effect.

  Moreover, in this invention, it is preferable that the total layer thickness of the some organic functional layer which comprises the said light emitting unit exists in the range of the number of light emitting units x (100-200) nm. By setting it within this range, it is considered that occurrence of a short circuit can be suppressed and an increase in driving voltage can be suppressed.

  Moreover, in this invention, it is preferable that the said intermediate electrode layer has a base layer containing the compound represented by the said General formula (1) or (2). Thus, when the conductive layer is formed on the intermediate electrode layer adjacent to the base layer, the silver atoms constituting the conductive layer of the intermediate electrode layer are combined with the silver affinity compound contained in the base layer. By interacting, the diffusion distance of silver atoms on the surface of the underlayer is reduced, and aggregation of silver at a specific location is suppressed.

  Further, in the present invention, each of the plurality of light emitting units includes a light emitting unit that has a hole transport layer as an organic functional layer and is disposed at a position closest to the transparent electrode on the light emitting side. It is preferable that the layer thickness of the hole transport layer included in the light emitting unit other than the layer thickness of the hole transport layer is 20 nm or more. Thereby, when the intermediate electrode functions as an anode, it is considered that silver ions contained in the intermediate electrode layer are prevented from diffusing up to the light emitting layer, thereby suppressing the occurrence of local electric field concentration.

  In the present invention, it is preferable that one of the pair of main electrodes is a transparent electrode that functions as an anode. Thereby, it is possible to efficiently extract emitted light from the light emitting layer by providing a light extraction film or the like on the anode side.

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

《Organic electroluminescence device》
The organic electroluminescence device of the present invention comprises an organic electroluminescence device comprising at least two light emitting units and an intermediate electrode layer disposed between the light emitting units between a pair of main electrodes, one of which is a transparent electrode Because
(1) The light emitting unit has a plurality of organic functional layers including a light emitting layer,
(2) Among the intermediate electrode layers, at least one intermediate electrode layer is a conductive layer containing silver as a main component,
(3) The light emitting unit that emits the light having the shortest wavelength in the light emitting layer is disposed at a position farthest from the transparent electrode on the main light emitting side of the organic electroluminescence element.
Below, the structure of the organic electroluminescent element of this invention, a component, etc. are demonstrated sequentially.
[Configuration of organic electroluminescence element]
First, an example of a basic configuration of the organic electroluminescence elements (hereinafter also referred to as “organic EL elements”) 100 and 200 of the present invention will be described with reference to the drawings. However, the organic EL elements 100 and 200 of the present invention are not limited to the configuration illustrated by using a specific example.

  The organic EL elements 100 and 200 of the present invention are provided between at least two light emitting units 3 and a light emitting unit 3 between a pair of main electrodes (first electrode 2 and second electrode 6), one of which is a transparent electrode. The intermediate electrode layer 4 is provided. The light emitting unit 3 has a plurality of organic functional layers including a light emitting layer. Of the intermediate electrode layers 4, at least one intermediate electrode layer 4 is a conductive layer containing silver as a main component. In addition, the light emitting unit 3 that emits the light having the shortest wavelength in the light emitting layer is disposed at a position farthest from the transparent electrode (first electrode 2) on the main light emission side of the organic EL elements 100 and 200. It is characterized by.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of an organic EL element 100 having two light emitting units 3A and 3B of the present invention. In FIG. 1, the organic EL element 100 includes a first electrode 2, a first light emitting unit 3 </ b> A, a base layer 41, an intermediate electrode layer 4 </ b> A, a second light emitting unit 3 </ b> B, and a second electrode 6 that are sequentially stacked on a transparent substrate 1. ,It is configured. Although the underlayer 41 is not an essential component, it includes a silver-affinity compound that is a nitrogen-containing aromatic compound, so that it has a high electron transport capability and can be suitably used as an electron transport material. Is preferred. A light extraction film (not shown) is formed on the opposite side of the transparent substrate 1 from the first electrode 2 side.
In the configuration of FIG. 1, the first electrode 2 is an anode that is a transparent electrode, and the second electrode 6 is a cathode. In this case, for example, when the first light emitting unit 3A is in the layer order of “hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer” from the transparent substrate 1 side, Similarly, the two light emitting units 3B are arranged in the order of “hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer” from the transparent substrate 1 side. In addition, an independent connection terminal (not shown) is disposed between the light emitting units 3A and 3B.

  The first electrode 2 and the intermediate electrode layer 4A are wired with lead wires, and the first light emitting unit 3A emits light when applied to each connection terminal as a drive power source V1 within a range of 2 to 40V. Similarly, between the intermediate electrode layer 4 </ b> A and the second electrode 6, the second light emitting unit 3 </ b> B is wired by a lead wire and applied to each connection terminal as a drive power source V <b> 2 within a range of 2 to 40 V. Emits light.

  Specifically, when driving the organic EL element 100, the drive voltage V1 applied between the first electrode 2 and the intermediate electrode layer 4A and the drive voltage V2 applied between the intermediate electrode layer 4A and the second electrode 6 are: When a DC voltage is applied, the first electrode 2 that is an anode has a positive polarity, the second electrode 6 that is a cathode has a negative polarity, and is applied within a voltage range of 2 to 40 V. Further, the intermediate electrode layer 4A For, an intermediate voltage between the voltage applied to the anode and the cathode is applied.

  The emitted light L emitted from the light emitting points h of the respective light emitting units 3A and 3B is extracted to the outside from the first electrode 2 side which is a transparent electrode. Further, the light emitted to the second electrode 6 side is reflected by the surface of the second electrode 6 and is similarly extracted from the first electrode 2 side.

The first electrode 2 and the second electrode 6 may be the anode, and the intermediate electrode layer 4A disposed between the two light emitting units 3A and 3B may be the cathode. In this case, as the drive voltage V1, a voltage of about 2 to 40V is applied so that the positive side is the first electrode 2 and the negative side is the intermediate electrode layer 4A, and the drive voltage V2 is a voltage of about 2 to 40V. The light emitting units 3A and 3B emit light by applying the second electrode 6 on the positive side and the intermediate electrode layer 4A on the negative side.
The layer configuration in this case is, for example, when the first light emitting unit 3A is in the layer order of “hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer” from the transparent substrate 1 side, for example In contrast, the second light emitting unit B has a reverse layer configuration of “electron injection layer, electron transport layer, light emitting layer, hole transport layer, hole injection layer” from the transparent substrate 1 side.

  FIG. 2 is a schematic cross-sectional view showing an example of the configuration of an organic EL element 200 having three light emitting units 3C, 3D, and 3E. In FIG. 2, the organic EL element 200 includes a first electrode 2, a first light emitting unit 3C, a first intermediate electrode layer 4B, a second light emitting unit 3D, a second intermediate electrode layer 4C, and a third light emitting on the transparent substrate 1. The unit 3E and the second electrode 6 are sequentially stacked and configured. In the first intermediate electrode layer 4B and the second intermediate electrode layer 4C on the transparent substrate 1 side, base layers 42 and 43 containing nitrogen atoms are provided, respectively. A light extraction film (not shown) is formed on the opposite side of the transparent substrate 1 from the first electrode 2 side. In the configuration of FIG. 2, the first electrode 2 is an anode that is a transparent electrode, and the second electrode 6 is a cathode. By providing a light extraction film or the like on the anode side, the emitted light L can be efficiently extracted from the light emitting layer. In this case, for example, when the first light emitting unit 3C is in the order of “hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer” from the transparent substrate 1 side, Similarly, the second light emitting unit 3D and the third light emitting unit 3E are arranged in the order of “hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer” from the transparent substrate 1 side.

  The first electrode 2 and the first intermediate electrode layer 4B are wired with lead wires, and the first light emitting unit 3C emits light by applying the driving voltage V1 to the respective connection terminals in the range of 2 to 40V. . Similarly, the first intermediate electrode layer 4B and the second intermediate electrode layer 4C are wired with lead wires, and applied to the respective connection terminals as a drive voltage V3 within a range of 2 to 40 V, whereby the second light emission. Unit 3D emits light. Similarly, the second intermediate electrode layer 4C and the second electrode 6 are also wired with lead wires, and applied to the respective connection terminals as a driving voltage V3 within a range of 2 to 40 V, whereby the third light emitting unit 3E. Emits light.

  When driving the organic EL element 200, as the driving voltage V1, the driving voltage V2, and the driving voltage V3, when a DC voltage is applied, the first electrode 2 that is an anode has a positive polarity and the second electrode that is a cathode. 6 is applied with a negative polarity within a voltage range of 2 to 40 V. Further, the first intermediate electrode layer 4B and the second intermediate electrode layer 4C are applied with a voltage between the anode and the cathode. Note that the organic EL element 200 having the three light emitting units 3C, 3D, and 3E also has the first electrode 2 and the second electrode 6 as anodes, as in the case of having the two light emitting units 3A and 3B. The intermediate electrode layer 4B and the second intermediate electrode layer 4C may be configured as cathodes.

[Configuration of light emitting unit]
In the organic EL elements 100 and 200 of the present invention, the light emitting unit 3 has a structure in which two or more light emitting units 3 are stacked between the first electrode 2 and the second electrode 6, and two or more light emitting units are provided. It is characterized in that the space between the three is separated by the intermediate electrode layer 4. In the present invention, three or more light emitting units 3 are stacked, and each light emitting unit 3 includes a light emitting unit 3 having a blue light emitting layer, a light emitting unit 3 having a green light emitting layer, and a light emitting unit 3 having a red light emitting layer. It can also be set as the structure which obtains the luminescent color of the desired hue including white.

  The total thickness of the plurality of organic functional layers constituting the light emitting unit 3 is preferably in the range of the number of light emitting units × (100 to 200) nm. By setting it within this range, it is considered that occurrence of a short circuit can be suppressed and an increase in driving voltage can be suppressed. Examples of the plurality of organic functional layers include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

  In addition, each of the plurality of light emitting units 3 has a hole transport layer as an organic functional layer, and the hole transport included in the light emitting unit 3 disposed at a position closest to the transparent electrode on the light emitting side. It is preferable that the layer thickness of the hole transport layer included in the light emitting unit 3 other than the layer thickness is 20 nm or more. Thereby, when the intermediate electrode functions as an anode, it is considered that silver ions contained in the intermediate electrode layer are prevented from diffusing up to the light emitting layer, thereby suppressing the occurrence of local electric field concentration.

  The overall layer structure of the light emitting unit 3 according to the present invention is not limited, and may have a general layer structure. As an example, a configuration in which “a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer” are stacked in this order from the first electrode 2 side serving as an anode is exemplified. Of this configuration, it is essential to have at least a light emitting layer using an organic material. The hole injection layer and the hole transport layer may be provided as a hole transport and injection layer. The electron transport layer and the electron injection layer may be provided as an electron transport and injection layer. Of the layers constituting the light emitting unit 3, for example, the electron injection layer may be made of an inorganic material.

  In addition to these layers, the light-emitting unit 3 may have a hole blocking layer, an electron blocking layer, and the like stacked as necessary. In addition, the light emitting layer may include each color light emitting layer that generates the emitted light L in each wavelength region, and the light emitting unit 3 may be formed by laminating each color light emitting layer via a non-light emitting intermediate layer. . The intermediate layer may function as a hole blocking layer and / or an electron blocking layer.

  Further, as illustrated in FIGS. 1 and 2, the light emitting unit 3 has a configuration in which three light emitting units 3C, 3D, and 3E are stacked, even though the two light emitting units 3A and 3B are stacked. There may be. Moreover, the structure from which the emitted light L of one color is obtained may be sufficient, and the emitted light L of a different color may be obtained.

[Light emitting unit arrangement]
An arrangement of a plurality of light emitting units having at least one light emitting layer among a blue light emitting layer that emits blue light, a green light emitting layer that emits green light, and a red light emitting layer that emits red light will be described. Specifically, for the organic EL elements 100 and 200 including two or more light emitting units 3, the arrangement of the light emitting units 3 is divided into a case where two light emitting units are provided (organic EL100) and a case where three light emitting units are provided (organic EL200). Will be explained.
When two light emitting units 3 are provided, as shown in FIG. 1, the organic EL element 100 includes an intermediate electrode layer 4A between the light emitting units 3 of the first light emitting unit 3A and the second light emitting unit 3B. The light emitting unit 3 that emits the light having the shortest wavelength among the light emitting layers may be arranged at a position farthest from the transparent electrode on the main light emission side of the organic EL element 100, and can be configured by various combinations. .
For example, when the organic EL element 100 includes two light-emitting units 3A and 3B, a light-emitting unit 3 having a red light-emitting layer that emits red light and a light-emitting unit 3 having a blue light-emitting layer that emits blue light. Since the blue light has a shorter wavelength, the light emitting unit 3 having the red light emitting layer is the light emitting unit 3 (first light emitting unit 3A) on the light emission side. On the other hand, the light emitting unit 3 having the blue light emitting layer is disposed in the light emitting unit 3 (second light emitting unit 3B) farthest from the transparent electrode on the light emission side.
Thereby, when the intermediate electrode layer 4 contains silver as a main component, it is excellent in power efficiency and light emission lifetime, has toning suitability, and has excellent light distribution characteristics (viewing angle dependency). The case where two light emitting layers are provided is not limited to the case where one light emitting unit 3 includes one light emitting layer. For example, one light emitting unit 3 may include a plurality of light emitting layers. For example, the first light emitting unit 3A may include a red light emitting layer and a green light emitting layer, and the second light emitting unit 3B may include a blue light emitting layer.

When three light emitting units 3 are provided, as shown in FIG. 2, the organic EL element 200 includes an intermediate electrode layer 4 between the light emitting units 3 of the first light emitting unit 3C, the second light emitting unit 3D, and the third light emitting unit 3E. (First intermediate electrode layer 4B and second intermediate electrode layer 4C) are provided. Also in the case where three light emitting units 3 are provided, the light emitting unit 3 that emits the light having the shortest wavelength in the light emitting layer is disposed at the farthest position from the transparent electrode on the main light emission side of the organic EL element 200. Thereby, the organic EL element 200 excellent in light distribution characteristics can be produced. Moreover, it is preferable that the light emitting unit 3 which has a green light emitting layer is arrange | positioned in the position nearest to the transparent electrode by the side of light emission.
Of the light emitting units 3, the light emitting unit 3 that emits light with the longest wavelength is preferably disposed between the two first intermediate electrode layers 4B and the second intermediate electrode layer 4C. Specifically, when each of the three light emitting units 3C, 3D, 3E includes one light emitting layer, for example, the light emitting unit 3 (first light emitting unit 3C) closest to the light emission side includes a green light emitting layer, The light emitting unit 3 (third light emitting unit 3E) furthest to the light emission side includes a blue light emitting layer, and is disposed between the two first intermediate electrode layers 4B and 4C among the three light emitting units 3. It is most preferable that the light emitting unit 3 (second light emitting unit 3D) to be provided includes a red light emitting layer. One light emitting unit 3 may have a plurality of light emitting layers, and the three light emitting units 3 may have a plurality of light emitting layers of the same color.

  Below, each component which comprises the organic EL elements 100 and 200 is demonstrated in detail.

[Transparent substrate]
Examples of the transparent substrate 1 applicable to the organic EL elements 100 and 200 include transparent materials such as glass and plastic. Examples of the transparent substrate 1 that is preferably used include glass, quartz, and resin films.

  Examples of the glass material include silica glass, soda lime silica glass, lead glass, borosilicate glass, and alkali-free glass. On the surface of these glass materials, from the viewpoint of adhesion with adjacent layers, durability, and smoothness, a physical treatment such as polishing, a coating made of an inorganic material or an organic material, or these coatings, if necessary. A combined hybrid coating can be formed.

  Examples of the constituent material 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 pro Cellulose esters such as pionate (CAP), cellulose acetate phthalate, cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether Ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, police Phones, polyether imides, polyether ketone imides, polyamides, fluororesins, nylon, polymethyl methacrylate, acrylics and polyarylates, cyclones such as Arton (trade name, manufactured by JSR) and Appel (trade name, manufactured by Mitsui Chemicals) An olefin resin etc. can be mentioned.

  The surface of the transparent substrate 1 is preferably cleaned by surface activation treatment. Examples of such surface activation treatment include corona treatment, plasma treatment, and flame treatment.

[Gas barrier layer]
The organic EL elements 100 and 200 of the present invention preferably have a configuration in which a gas barrier layer is provided on the transparent substrate 1 according to the present invention.
The transparent substrate 1 on which the gas barrier layer is formed has a water vapor permeability of 1 × 10 ⁻³ at a temperature of 25 ± 0.5 ° C. and a relative humidity of 90 ± 2% RH measured by a method according to JIS K 7129-1992. is preferably g ^/ m 2 · 24h or less, more, oxygen permeability measured by the method based on JIS K 7126-1987 ^{is, 1 × 10 -3 ml / m} 2 · 24h · atm (1atm is , 1.01325 × a ¹⁰ 5 Pa) equal to or lower than a temperature of 25 ± 0.5 ° C., water vapor permeability at a relative humidity of 90 ± 2% RH is below ^{1 × 10 -3 g / m 2} · 24h Preferably there is.

  As a material for forming the gas barrier layer, any material may be used as long as it has a function of suppressing intrusion of elements such as moisture and oxygen that cause deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Furthermore, in order to improve the brittleness of the gas barrier layer, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. 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 forming the gas barrier layer is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is also preferable. In addition, the polysilazane-containing liquid is applied and dried by a wet coating method, and the formed coating film is irradiated with vacuum ultraviolet light (VUV light) having a wavelength of 200 nm or less, and the formed coating film is subjected to a modification treatment, and gas A method of forming a barrier layer is also preferable.

  The thickness of the gas barrier layer is preferably in the range of 1 to 500 nm, more preferably in the range of 10 to 300 nm. If the thickness of the gas barrier layer is 1 nm or more, a desired gas barrier performance can be exhibited, and if it is 500 nm or less, film quality deterioration such as generation of cracks in a dense silicon oxynitride film can be prevented. Can do.

[First electrode]
The first electrode 2 is a transparent electrode that functions as an anode when provided on one surface side of the transparent substrate 1. When the anode is a transparent electrode, it is possible to efficiently extract emitted light from the light emitting layer by providing a light extraction film on the anode side. The first electrode 2 is an extremely thin metal film to such an extent that the light transmission can be maintained and the irradiated light is not lost to plasmon. Specifically, the light transmittance at a wavelength of 550 nm is 60% or more, the film thickness is 1 to 30 nm, and the sheet resistance is 0.0001 to 50Ω / □, preferably 0.01 to 30Ω / □.

When the first electrode 2 is used as an anode in the organic EL elements 100 and 200, a material having a high work function (4 eV or more) metal, alloy, electrically conductive compound, or a mixture thereof is preferably used. . Specific examples of such an electrode material include metals such as Au, conductive transparent materials such as CuI, indium-tin composite oxide (ITO), SnO ₂ and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. The anode may be formed by depositing a thin film of these electrode materials by vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.
Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used.

[Intermediate electrode layer]
The organic EL elements 100 and 200 of the present invention have a structure in which two or more light emitting units 3 are stacked between the first electrode 2 and the second electrode 6, and between the two or more light emitting units 3, It is characterized by having a structure separated by an intermediate electrode layer 4 (4A or 4B and 4C) having independent connection terminals for obtaining electrical connection.
As the intermediate electrode layer 4 according to the present invention, at least one intermediate electrode layer 4 is a conductive layer containing silver as a main component. The intermediate electrode layer 4 is a transparent layer having a light transmittance of 60% or more at a wavelength of 550 nm.
Further, the intermediate electrode layer 4 is not particularly limited, but a configuration having the base layers 41, 42, and 43 is preferable. Details of the underlayers 41, 42, and 43 will be described later.

  The intermediate electrode layer 4 preferably has a layer thickness in the range of 1 to 30 nm, and more preferably in the range of 3 to 20 nm. By making the layer thickness within the above range, the absorption component or reflection component of the layer can be kept low, and the light transmittance is maintained, which is preferable. Also, conductivity is ensured.

  As a method for forming such an intermediate electrode layer 4, a method using a wet process such as a coating method, an inkjet method, a coating method, a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like. And a method using a dry process such as Of these, the vapor deposition method is preferably applied. The intermediate electrode layer 4 is preferably formed on the layer containing nitrogen atoms of the underlayers 41, 42, and 43, and has sufficient conductivity even without high-temperature annealing after the film formation. Although it is characterized, high-temperature annealing treatment or the like may be performed after the film formation, if necessary.

The purity of silver constituting the intermediate electrode layer 4 is preferably 99% or more. Further, palladium (Pd), copper (Cu), gold (Au), or the like may be added to ensure the stability of silver.
Moreover, when the intermediate electrode layer 4 is comprised from the alloy which has silver as a main component, it is preferable that the silver content rate is 50% or more. Examples of such alloys include silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), silver indium (AgIn), silver gold (AgAu), silver aluminum (AgAl) Silver zinc (AgZn), silver tin (AgSn), silver platinum (AgPt), silver titanium (AgTi), silver bismuth (AgBi), and the like.

  Further, the intermediate electrode layer 4 as described above may have a structure in which silver or an alloy layer mainly containing silver is divided into a plurality of layers as necessary. That is, a configuration in which silver layers and alloy layers are alternately stacked a plurality of times may be used, or a configuration in which a plurality of layers of different alloys are stacked may be used. Further, as an example in which the intermediate electrode layer 4 has a two-layer structure, a configuration in which a silver layer is stacked on the base layers 41, 42, and 43 via an aluminum (Al) layer can be given. In this case, the aluminum layer may not be a continuous layer, but may be a layer having islands or holes. A part of the silver layer is provided adjacent to the base layers 41, 42 and 43. Thus, the structure which pinched | interposed another metal between the base layers 41, 42, and 43 and the layer which has silver as a main component may be sufficient.

[Underlayer]
In the organic EL elements 100 and 200 of the present invention, a configuration in which the underlayers 41, 42, and 43 provided on at least one surface side of the intermediate electrode layer 4 include a compound containing a nitrogen atom is a preferred embodiment.
The nitrogen atom-containing compound contained in the underlayers 41, 42 and 43 is not particularly limited as long as it is a compound containing a nitrogen atom in the molecule, but a compound having a heterocycle having a nitrogen atom as a hetero atom is preferable. . Examples of the heterocycle having a nitrogen atom as a hetero atom include aziridine, azirine, azetidine, azeto, azolidine, azole, azinane, pyridine, azepan, azepine, imidazole, pyrazole, oxazole, thiazole, imidazoline, pyrazine, morpholine, thiazine, indole, Examples include isoindole, benzimidazole, purine, quinoline, isoquinoline, quinoxaline, cinnoline, pteridine, acridine, carbazole, benzo-C-cinnoline, porphyrin, chlorin and choline.

Furthermore, the nitrogen atom-containing compound contained in the underlayers 41, 42 and 43 is preferably an aromatic heterocyclic compound having a nitrogen atom having an unshared electron pair not involved in aromaticity.
In the present invention, a nitrogen atom having an unshared electron pair not involved in aromaticity is a nitrogen atom having an unshared electron pair (also referred to as “lone electron pair”), and is an aromatic of an unsaturated cyclic compound. The nitrogen atom in which the unshared electron pair is not directly involved as an essential element. That is, the unshared electron pair is involved in the delocalized π-electron system on the conjugated unsaturated ring structure (aromatic ring) as an essential element for the expression of aromaticity in the chemical structural formula. No nitrogen atom.

  The aromaticity here means that in a conjugated (resonant) unsaturated ring structure in which atoms having π electrons are arranged in a ring, the number of electrons contained in a delocalized π electron system on the ring is 4n + 2 ( n = 0 or a natural number) (so-called Hückel rule). For example, a nitrogen atom of pyridine, a nitrogen atom of an amino group as a substituent, and the like correspond to “a nitrogen atom having an unshared electron pair not involved in aromaticity” according to the present invention.

  The aromatic heterocyclic compound contained in the nitrogen atom-containing layer is not particularly limited as long as it has a nitrogen atom having an unshared electron pair not involved in aromaticity in the molecule. Preferably has a pyridine ring in the molecule, more preferably has an azacarbazole ring, azadibenzofuran ring or azadibenzothiophene ring in the molecule, and more preferably γ, γ′-dia in the molecule. It has a carbazole ring or σ-carboline ring.

  The aromatic heterocyclic compound contained in the underlayers 41, 42 and 43 containing nitrogen atoms is preferably a compound represented by the general formula (1) or (2). In addition, the compound represented by any one of the general formula (3), the general formula (4), the general formula (5), or the general formula (6) is also an aromatic heterocyclic ring contained in the underlayers 41, 42, and 43. It can be preferably used as a compound.

In the general formula (1), Y ₁ represents a divalent linking group composed of an arylene group, a heteroarylene group, or a combination thereof. E _{1 to} E ₃₄ each represent C (R ₁ ) or N, and R ₁ represents a hydrogen atom or a substituent. However, at least one of E _{17 to} E ₂₅ and at least one of E _{26 to} E ₃₄ represent N. k1 and k2 represent an integer of 0 to 4, and k1 + k2 is an integer of 2 or more.

In the general formula (1), examples of the arylene group represented by Y ₁ include o-phenylene group, p-phenylene group, naphthalenediyl group, anthracenediyl group, naphthacenediyl group, pyrenediyl group, naphthylnaphthalenediyl group, and biphenyl. Diyl group (for example, [1,1′-biphenyl] -4,4′-diyl group, 3,3′-biphenyldiyl group, 3,6-biphenyldiyl group), terphenyldiyl group, quaterphenyldiyl Group, kinkphenyldiyl group, sexiphenyldiyl group, septiphenyldiyl group, octiphenyldiyl group, nobiphenyldiyl group, and deciphenyldiyl group.

In the general formula (1), examples of the heteroarylene group represented by Y ₁ include a carbazole ring, a carboline ring, a diazacarbazole ring (also referred to as a monoazacarboline ring, and one of carbon atoms constituting the carboline ring). Derived from the group consisting of triazole ring, pyrrole ring, pyridine ring, pyrazine ring, quinoxaline ring, thiophene ring, oxadiazole ring, dibenzofuran ring, dibenzothiophene ring and indole ring) And the like.

As a preferable embodiment of the divalent linking group composed of an arylene group, heteroarylene group or a combination thereof represented by Y ₁ , a condensed aromatic heterocycle formed by condensation of three or more rings among heteroarylene groups The group derived from a condensed aromatic heterocycle formed by condensation of three or more rings is preferably a group derived from a dibenzofuran ring or a dibenzothiophene ring. Preferred are the groups

In the general formula _(1), indicating -C _(R 1) = of _{R 1} represented by each of E 1 _{to E 34} is an example of a substituent when a substituent below.

  Examples of this substituent include alkyl groups (eg, methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl and pentadecyl groups. Etc.), cycloalkyl groups (eg, cyclopentyl and cyclohexyl groups), alkenyl groups (eg, vinyl and allyl groups), alkynyl groups (eg, ethynyl and propargyl groups), aromatic hydrocarbon groups (aromatic For example, a 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 and biphenylyl groups), aromatic hetero Groups (e.g. furyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, imidazolyl, pyrazolyl, thiazolyl, quinazolinyl, carbazolyl, carbolinyl, diazacarbazolyl ( Any carbon atom constituting the carboline ring of the carbolinyl group is substituted with a nitrogen atom) and phthalazinyl group), a heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.) An alkoxy group (for example, a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group and a dodecyloxy group), a cycloalkoxy group (for example, a cyclopentyloxy group and a cyclohexyloxy group), Ally An oxy group (for example, phenoxy group and naphthyloxy group), an alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group and dodecylthio group), a cycloalkylthio group (for example, cyclopentylthio group) Group and cyclohexylthio group), arylthio group (for example, phenylthio group and naphthylthio group), alkoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group and dodecyloxycarbonyl group) Group), aryloxycarbonyl group (for example, phenyloxycarbonyl group and naphthyloxycarbonyl group), sulfamoyl group (for example, aminosulfonyl group, methylaminos) Sulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group and 2-pyridylaminosulfonyl group) An 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 and pyridylcarbonyl group) Etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group) , Dodecylcarbonyloxy group and phenylcarbonyloxy group), 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, propylaminocarbonyl group) Pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, Silaminocarbonyl 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 and 2-pyridylaminoureido group), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group) Group, naphthylsulfinyl group and 2-pyridylsulfinyl group), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, Acetylsulfonyl 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, etc.], halogen atoms (for example, fluorine atom, chlorine atom and bromine atom), fluorinated hydrocarbon groups (for example, fluoromethyl group, trifluoromethyl) Group, pentaf Oroethyl group and pentafluorophenyl group), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group and phenyldiethylsilyl group), phosphate ester Examples thereof include a group (for example, dihexyl phosphoryl group), a phosphite group (for example, diphenylphosphinyl group), a phosphono group, and the like.

  Some of these substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

In the general formula (1), it is preferable that six or more of E _{1 to} E ₈ and six or more of E _{9 to} E ₁₆ are each represented by —C (R ₁ ) ═.

In the general formula (1), it is preferable that at least one of E _{21 to} E ₂₅ and at least one of E _{30 to} E ₃₄ represent —N═.

Further, in the general formula _(1), any one of any one and _E 30 _{to E 34} of E 21 _{to E 25} is preferably representative of the -N =.

In the general formula _{(1), E} 17 ~E ₂₀ and _E 26 _{to E 29} may be mentioned as each -C _(R 1) = are preferable embodiments be represented by.

Furthermore, in the compound represented by the general formula (1), it is preferable that E ₃ is represented by —C (R ₁ ) ═ and R ₁ represents a linking site, and E ₁₁ is also represented by —C (R ₁ ) = and R ₁ preferably represents a linking site.

Further, E ₂₁ and E ₃₀ are preferably represented by —N═, and E _{17 to} E ₂₀ and E _{26 to} E ₂₉ are each preferably represented by —C (R ₁ ) ═.

In the formula of the general formula (2), at least one of E ₁ and E ₂ is a nitrogen atom, at least one of E _{6 to} E ₁₀ is a nitrogen atom, and E _{11 to} E ₁₅ At least one of them is a nitrogen atom. R ₁ represents a substituent.

In the general formula (2), when R ₁ represents a substituent, examples of the substituent include the substituents exemplified as R _{1 in the} general formula (1).

In the formula of the general formula (3), E _{1 to} E ₈ each represent C (R ₂ ) or N, and at least one of E _{1 to} E ₈ is N. Further, _{R 1} in general formula (3), and said _{R 2} represents a hydrogen atom or a substituent. As the substituent, the substituents exemplified as R ₁ in the general formula (1) are similarly applied.

The general formula (4) is also an embodiment of the general formula (3). In the formula of the general formula (4), E _{1 to} E ₁₂ each represent —C (R ₁ ) ═, and R ₁ represents a hydrogen atom or a substituent. Y ₁ represents a divalent linking group composed of an arylene group, a heteroarylene group, or a combination thereof.

In the general formula _(4), if -C _(R 1) = of _{R 1} represented by each of E 1 _{to E 12} is a substituent, and examples of the substituent of the general formula (3) R _The substituents exemplified as ₁ apply analogously.

In general formula (4), the arylene group represented by Y _1, a preferred embodiment of the divalent linking group of a heteroarylene group, or a combination thereof, is the same as Y ₁ in the general formula (1) Can be mentioned.

The general formula (5) is also an embodiment of the general formula (3). In the formula (5), E _{1 to} E ₁₄ each represent —C (R ₁ ) ═, and R ₁ represents a hydrogen atom or a substituent. Ar ₁ represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocyclic ring. Furthermore, k1 represents an integer of 3 or more.

In the general formula _(5), if -C _(R 1) = of _{R 1} represented by each of E 1 _{to E 14} is a substituent, and examples of the substituent of the general formula (1) R _The substituents exemplified as ₁ apply analogously.

In the general formula (5), when Ar ₁ represents an aromatic hydrocarbon ring, examples of the aromatic hydrocarbon ring include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, Chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, Examples include a pentaphen ring, a picene ring, a pyrene ring, a pyranthrene ring, and an anthraanthrene ring. These rings may further have the substituents exemplified as R _{1 in the} general formula (3).

In the general formula (5), when Ar ₁ represents an aromatic heterocyclic ring, the aromatic heterocyclic ring includes a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, and a pyrazine ring. , Triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole And a ring and an azacarbazole ring. The azacarbazole ring refers to one in which at least one carbon atom of the benzene ring constituting the carbazole ring is replaced with a nitrogen atom. These rings may further have the substituent exemplified as R ₁ in the general formula (1).

In the formula (6), E _{1 to} E ₁₂ each represent —C (R ₁ ) ═ or N═, and R ₁ represents a hydrogen atom or a substituent. Ar ₁ represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocyclic ring.

In the general formula _(6), if -C _(R 1) = of _{R 1} represented by each of E 1 _{to E 12} is a substituent, and examples of the substituent of the general formula (1) R _The substituents exemplified as ₁ apply analogously.

In general formula (6), represented by Ar _1, substituted or unsubstituted, aromatic hydrocarbon ring or aromatic heterocyclic ring include the same as Ar ₁ in formula (5).

[Specific examples of aromatic heterocyclic compounds contained in the underlayer]
Specific examples No. of aromatic heterocyclic compounds containing nitrogen atoms having unshared electron pairs not involved in aromaticity, contained in the underlayers 41, 42 and 43 according to the present invention will be described below. 1-No. 40. No. 1-No. 40 is a specific example of a compound represented by the general formulas (1), (2), (3), (4), (5) and (6).

  Specific examples AN1 to 118 of aromatic heterocyclic compounds containing nitrogen atoms having unshared electron pairs not involved in aromaticity, contained in the base layers 41, 42 and 43 according to the present invention are shown below. AN1 to 118 show specific examples other than the compounds represented by the general formulas (1), (2), (3), (4), (5) and (6), but are not limited thereto. Absent.

(Formation method of underlayer)
As a formation method of the underlayers 41, 42 and 43 having a layer containing nitrogen atoms, a method using a wet process such as a coating method, an inkjet method, a coating method or a dip method, a vapor deposition method (resistance heating or EB method, etc.) ), A method using a dry process such as a sputtering method or a CVD method. Of these, the vapor deposition method is preferably applied.

  In particular, when the underlying layers 41, 42, and 43 are formed using a plurality of compounds, there is a film forming method in which a plurality of compounds are simultaneously supplied from a plurality of evaporation sources or a plurality of compounds are sequentially stacked. Applied. Specifically, a film forming method in which a compound that can be used for the above-described base layers 41, 42, and 43 and, for example, potassium fluoride or lithium is co-evaporated or stacked is applied. Moreover, if a polymer material is used as the compound, a coating method is preferably applied. In this case, a coating solution in which the compound is dissolved in a solvent is used. The solvent is not limited as long as it can dissolve the compound. Furthermore, if the underlayers 41, 42, and 43 containing nitrogen atoms are formed using a plurality of compounds, a coating solution may be prepared using a solvent that can dissolve the plurality of compounds. .

[Light emitting unit]
Hereinafter, each layer constituting the light emitting unit 3 will be described in the order of the light emitting layer, the injection layer, the hole transport layer, the electron transport layer, and the blocking layer.

(Light emitting layer)
The light emitting layer constituting the light emitting unit 3 of the organic EL elements 100 and 200 preferably includes a phosphorescent light emitting compound as a light emitting material.

  This light emitting layer is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer and holes injected from the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer.

  As such a light emitting layer, there is no restriction | limiting in particular in the structure, if the light emitting material contained satisfy | fills 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 intermediate layer between the light emitting layers.

  The total thickness of the light emitting layers 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 thickness of a light emitting layer is the thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  In the case of a light emitting layer having a configuration in which a plurality of layers are laminated, the thickness of each light emitting layer is preferably adjusted within the range of 1 to 50 nm, more preferably adjusted within the range of 1 to 20 nm. More preferred. 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.

  For the light emitting layer as described above, a light emitting material and a host compound to be described later may be used by publicly known methods such as a vacuum deposition method, a spin coating method, a casting method, an LB method (Langmuir-Blodget, Langmuir Broadgett method), and an ink jet method. Can be formed.

  In the light emitting layer, a plurality of light emitting materials may be mixed, and a phosphorescent light emitting material and a fluorescent light emitting material (also referred to as a fluorescent dopant or a fluorescent compound) may be mixed and used in the same light emitting layer. The structure of the light-emitting layer preferably includes a host compound (also referred to as a light-emitting host) and a light-emitting material (also referred to as a light-emitting dopant compound), and emits light from the light-emitting material.

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

  As the host compound, a known host compound may be used alone, or a plurality of types of host compounds may be used. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the efficiency of the organic electroluminescent device can be improved. 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 in the light emitting layer may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )

  The known host compound is preferably a high Tg (glass transition point) compound that has a hole transporting ability or an electron transporting ability and prevents emission of longer wavelengths. The glass transition point (Tg) here is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Hereinafter, H1 to H79 are shown as specific examples of the host compound applicable to the light emitting unit 3, but are not limited thereto. In the host compound H68, x and y represent the ratio of the random copolymer. The ratio can be, for example, x: y = 1: 10. Moreover, also about the host compound H69, p, q, and r represent a ratio.

  Specific examples of known host compounds applicable to the present invention include compounds described in the following documents. 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. , 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

<Light emitting material>
Examples of the light-emitting material that can be used in the present invention include phosphorescent compounds (also referred to as phosphorescent compounds or phosphorescent materials) and fluorescent compounds (also referred to as fluorescent compounds or fluorescent materials). It is done.

<Phosphorescent compound>
A phosphorescent compound 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.), and the phosphorescence quantum yield is 0 at 25 ° C. A preferred phosphorescence quantum yield is 0.1 or more, although it is defined as 0.01 or more compounds.

  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 the solution can be measured using various solvents, but when using a phosphorescent compound in the present invention, the phosphorescence quantum yield is 0.01 or more in any solvent. Should be achieved.

  There are two methods as the principle of light emission of the phosphorescent compound. One method is that the carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent compound to transfer the energy from the phosphorescent compound. It is an energy transfer type that obtains luminescence. Another method is a carrier trap type in which a phosphorescent compound serves as a carrier trap, carrier recombination occurs on the phosphorescent compound, and light emission from the phosphorescent compound is obtained. In either case, the condition is that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

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

  In the present invention, at least one light emitting layer may contain two or more phosphorescent compounds, and the concentration ratio of the phosphorescent compound in the light emitting layer varies in the thickness direction of the light emitting layer. It may be an embodiment.

  As content of a phosphorescence-emitting compound, Preferably it is the range of 0.1-30 volume% with respect to the total amount of a light emitting layer.

<1> Compound Represented by General Formula (A) In the present invention, a compound represented by the following general formula (A) is preferably used as the phosphorescent compound.

  The phosphorescent compound represented by the following general formula (A) (also referred to as a phosphorescent metal complex) is preferably contained in the light emitting layer of the organic EL elements 100 and 200 as a light emitting dopant. Although it is an aspect, you may contain in light emission units 3 other than a light emitting layer.

In the general formula (A), P and Q each represent a carbon atom or a nitrogen atom. A ₁ represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocyclic ring together with P—C. A ₂ represents an atomic group that forms an aromatic heterocycle with QN. P ₁ -L ₁ -P ₂ represents a bidentate ligand, and P ₁ and P ₂ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L ₁ represents an atomic group that forms a bidentate ligand together with P ₁ and P ₂ . j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table.

In the general formula (A), examples of the aromatic hydrocarbon ring that A ₁ forms with P—C include, for example, a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, Naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, Examples include a picene ring, a pyrene ring, a pyranthrene ring and an anthraanthrene ring.

  These rings may further have a substituent. Examples of such a substituent include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group). Hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group and pentadecyl group), cycloalkyl group (for example, cyclopentyl group and cyclohexyl group), alkenyl group (for example, vinyl group and allyl group), alkynyl group (For example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (also called 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, indium Nyl, pyrenyl and biphenylyl groups), aromatic heterocyclic groups (eg furyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, imidazolyl, pyrazolyl, thiazolyl, quinazolinyl) Group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom) and a phthalazinyl group), a heterocyclic group ( For example, 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.), cyclo An alkoxy group (eg, cyclope Tiloxy group and cyclohexyloxy group), aryloxy group (for example, phenoxy group and naphthyloxy group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc. ), A cycloalkylthio group (for example, cyclopentylthio group and cyclohexylthio group), an arylthio group (for example, phenylthio group and naphthylthio group), an alkoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl) Group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfa Moyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthyl) Aminosulfonyl group and 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, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group) Butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group) Group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group and naphthylcarbonylamino group), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, Dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl Bonyl 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, 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, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (For example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group and 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 referred to as piperidinyl group) and 2,2,6,6-tetramethylpiperidinyl group), halogen atom (for example, fluorine atom, chlorine atom and bromine atom), fluorinated hydrocarbon Group , Fluoromethyl group, trifluoromethyl group, pentafluoroethyl group and pentafluorophenyl group), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group) Group and phenyldiethylsilyl group), phosphoric ester group (for example, dihexyl phosphoryl group, etc.), phosphite group (for example, diphenylphosphinyl group, etc.) and phosphono group.

The general formula (A), the aromatic heterocyclic ring A ₁ is formed together with P-C, for example, furan ring, thiophene ring, oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, Triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring And an azacarbazole ring.

  Here, the azacarbazole ring refers to one in which one or more carbon atoms of the benzene ring constituting the carbazole ring are replaced with nitrogen atoms.

  These rings may further have the above-described substituent.

In the general formula (A), examples of the aromatic heterocycle formed by A ₂ together with QN include an oxazole ring, an oxadiazole ring, an oxatriazole ring, an isoxazole ring, a tetrazole ring, a thiadiazole ring, and a thiatriazole ring. , Isothiazole ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, pyrazole ring and triazole ring.

  These rings may further have the above-described substituent.

In the general formula (A), P ₁ -L ₁ -P ₂ represents a bidentate ligand, and P ₁ and P ₂ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L ₁ represents an atomic group forming a bidentate ligand together with P ₁ and P ₂ .

Examples of the bidentate ligand represented by P ₁ -L ₁ -P ₂ include phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, acetylacetone, and picolinic acid.

  In the general formula (A), j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 represents 2 or 3. Among these, j2 is preferably 0.

In General Formula (A), as M ₁ , a transition metal element of Group 8 to Group 10 (also simply referred to as a transition metal) in the periodic table is used, and among these, iridium is preferable.

<2> Compound Represented by General Formula (B) The compound represented by the general formula (A) described above is preferably a compound represented by the following general formula (B).

In the general formula (B), Z represents a hydrocarbon ring group or a heterocyclic group. P and Q each represent a carbon atom or a nitrogen atom. A ₁ represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocyclic ring together with P—C. A ₃ represents -C (R ₀₁ ) = C (R ₀₂ )-, -N = C (R ₀₂ )-, -C (R ₀₁ ) = N- or -N = N-, and R ₀₁ and R ₀₂ Each represents a hydrogen atom or a substituent. P ₁ -L ₁ -P ₂ represents a bidentate ligand. P ₁ and P ₂ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L ₁ represents an atomic group that forms a bidentate ligand together with P ₁ and P ₂ . j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table.

In the general formula (B), examples of the hydrocarbon ring group represented by Z include a non-aromatic hydrocarbon ring group and an aromatic hydrocarbon ring group, and examples of the non-aromatic hydrocarbon ring group include a cyclopropyl group. , Cyclopentyl group, cyclohexyl group and the like. These groups may be unsubstituted or may have the same substituents that the ring represented by A ₁ in the general formula (A) may have.

  Examples of the aromatic hydrocarbon ring group (also referred to as an aromatic hydrocarbon group or an aryl group) include, for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, and azulenyl. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like.

These groups may be unsubstituted or may have a substituent. Examples of such a substituent include the same substituents that the ring represented by A ₁ in the general formula (A) may have.

  In the general formula (B), examples of the heterocyclic group represented by Z include a non-aromatic heterocyclic group and an aromatic heterocyclic group. Examples of the non-aromatic heterocyclic group include an epoxy ring and an aziridine group. Ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε- Caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine Ring, thiomorpholine-1,1-dioxy And groups derived from a dodo ring, a pyranose ring and a diazabicyclo [2,2,2] -octane ring.

These groups may be unsubstituted or may have a substituent, and as such a substituent, the ring represented by A ₁ in the general formula (A) may have. The same thing as a substituent is mentioned.

  Examples of the aromatic heterocyclic group include pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl). Group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group , Benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), quinoxalinyl Group, pyridazinyl group, triazinyl group, Nazoriniru group and a phthalazinyl group, and the like.

These groups may be unsubstituted or may have a substituent, and as such a substituent, the ring represented by A ₁ in the general formula (A) may have. The same thing as a substituent is mentioned.

  Preferably, the group represented by Z is an aromatic hydrocarbon ring group or an aromatic heterocyclic group.

In the general formula (B), examples of the aromatic hydrocarbon ring that A ₁ forms with P—C include, for example, a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, Naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, Examples include a picene ring, a pyrene ring, a pyranthrene ring and an anthraanthrene ring.

These rings may further have a substituent, and the substituent is the same as the substituent that the ring represented by A ₁ in the general formula (A) may have. Things.

In the general formula (B), examples of the aromatic heterocycle formed by A ₁ together with P—C include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine. Ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, And a carboline ring and an azacarbazole ring.

  Here, the azacarbazole ring refers to one in which one or more carbon atoms of the benzene ring constituting the carbazole ring are replaced with nitrogen atoms.

These rings may further have a substituent, and the substituent is the same as the substituent that the ring represented by A ₁ in the general formula (A) may have. Things.

In -C (R ₀₁ ) = C (R ₀₂ )-, -N = C (R ₀₂ )-, or -C (R ₀₁ ) = N- represented by A ₃ in the general formula (B), R ₀₁ And the substituent represented by R ₀₂ has the same meaning as the substituent which the ring represented by A ₁ in the general formula (A) may have.

In the general formula (B), examples of the bidentate ligand represented by P ₁ -L ₁ -P ₂ include phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, acetylacetone, and picoline. An acid etc. are mentioned.

  J1 represents an integer of 1 to 3, and j2 represents an integer of 0 to 2, j1 + j2 represents 2 or 3, and j2 is preferably 0.

Element in the general formula (B), (also referred to simply as a transition metal) group 8-10 transition metal elements in the periodic table represented by M _1, the In the formula (A), represented by M ₁ It is synonymous with the transition metal element of 8th group-10th group in a periodic table.

<3> Compound Represented by General Formula (C) In the present invention, one preferred embodiment of the compound represented by the general formula (B) is a compound represented by the following general formula (C). It is done.

In the above general formula (C), R ₀₃ represents a substituent. R ₀₄ represents a hydrogen atom or a substituent, and a plurality of R ₀₄ may be bonded to each other to form a ring. n01 represents an integer of 1 to 4. R ₀₅ represents a hydrogen atom or a substituent, and a plurality of R ₀₅ may be bonded to each other to form a ring. n02 represents an integer of 1 to 2. R ₀₆ represents a hydrogen atom or a substituent, and may combine with each other to form a ring. n03 represents an integer of 1 to 4. Z ₁ represents an atomic group necessary for forming a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle together with C—C. Z ₂ represents an atomic group necessary for forming a hydrocarbon ring group or a heterocyclic group. P ₁ -L ₁ -P ₂ represents a bidentate ligand, and P ₁ and P ₂ each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L ₁ represents an atomic group forming a bidentate ligand together with P ₁ and P ₂ . j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table. R ₀₃ and R ₀₆ , R ₀₄ and R _06, and R ₀₅ and R ₀₆ may be bonded to each other to form a ring.

In the general formula (C), each of the substituents represented by R ₀₃ , R ₀₄ , R ₀₅ and R ₀₆ may be substituted by the ring represented by A ₁ in the general formula (A). Synonymous with group.

In the general formula (C), examples of the 6-membered aromatic hydrocarbon ring formed by Z ₁ together with C—C include a benzene ring.

These rings may further have a substituent, and such a substituent is the same as the substituent which the ring represented by A ₁ in the general formula (A) may have. Things.

In the general formula (C), examples of the 5-membered or 6-membered aromatic heterocycle formed by Z ₁ together with C—C include an oxazole ring, an oxadiazole ring, an oxatriazole ring, an isoxazole ring, a tetrazole ring, Examples include thiadiazole ring, thiatriazole ring, isothiazole ring, thiophene ring, furan ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, pyrazole ring and triazole ring.

These rings may further have a substituent, and such a substituent is the same as the substituent which the ring represented by A ₁ in the general formula (A) may have. Things.

In the general formula (C), examples of the hydrocarbon ring group represented by Z ₂ include a non-aromatic hydrocarbon ring group and an aromatic hydrocarbon ring group, and examples of the non-aromatic hydrocarbon ring group include cyclopropyl. Group, cyclopentyl group, cyclohexyl group and the like. These groups may be unsubstituted or may have a substituent. Examples of such a substituent include a substituent that the ring represented by A ₁ in General Formula (A) may have. The same thing as a group is mentioned.

Examples of the aromatic hydrocarbon ring group (also referred to as an aromatic hydrocarbon group or an aryl group) include, for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, and azulenyl. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like. These groups may be unsubstituted or may have a substituent. Examples of such a substituent include a substituent that the ring represented by A ₁ in General Formula (A) may have. The same thing as a group is mentioned.

In the general formula (C), examples of the heterocyclic group represented by Z ₂ include a non-aromatic heterocyclic group and an aromatic heterocyclic group. Examples of the non-aromatic heterocyclic group include an epoxy ring, Aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε -Caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thio Morpholine ring, thiomorpholine-1,1-dioxy De ring, pyranose ring, a diazabicyclo [2,2,2] - and the groups derived from the octane ring. These groups may be unsubstituted or may have a substituent. Examples of such a substituent include the same substituents that the ring represented by A ₁ in the general formula (A) may have.

  Examples of the aromatic heterocyclic group include pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl). Group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group , Benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), quinoxalinyl Group, pyridazinyl group, triazinyl group, Nazoriniru group and a phthalazinyl group, and the like.

These rings may be unsubstituted or may have a substituent. Examples of such a substituent include the same substituents that the ring represented by A ₁ in the general formula (A) may have.

In the general formula (C), the group formed by Z ₁ and Z ₂ is preferably a benzene ring.

In formula _(C), bidentate ligand represented by P 1 _-L 1 -P _2, the In formula _(A), the bidentate represented by P 1 _-L 1 -P ₂ Synonymous with ligand.

In the formula (C), expressed group 8-10 transition metal elements in the periodic table is at _{M 1,} wherein in the general formula (A), group 8 in the periodic table represented by _{M 1} to 10 It is synonymous with the group transition metal element.

  Further, the phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL element 100 and used.

  The phosphorescent compound according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound) ), Rare earth complexes, and most preferred are iridium compounds.

  Specific examples (Pt-1 to Pt-3, Os-1, Ir-1 to Ir-50) of the phosphorescent compounds according to the present invention are shown below, but the present invention is not limited thereto. In these compounds, m and n each represent the number of repetitions.

  The phosphorescent compound (also referred to as a phosphorescent metal complex) is described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and the methods described in references in these documents should be applied. Can be synthesized.

<Fluorescent compound>
Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. And dyes, polythiophene dyes, and rare earth complex phosphors.

(Injection layer)
An injection layer (a hole injection layer and an electron injection layer) is a layer provided between an electrode and a light-emitting layer in order to reduce drive voltage or improve light emission luminance. The details are described in Chapter 2, “Electrode Materials” (pp. 123-166) of Volume 2 of “November 30, 1998, issued by NTS Corporation”. There is.

  The injection layer can be provided as necessary. If it is a hole injection layer, it may be present between the anode and the light emitting layer or the hole transport layer, and if it is an electron injection layer, it may be present between the cathode and the light emitting layer or the electron transport layer.

  The details of the hole injection layer are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, and the like. As specific examples, a phthalocyanine layer represented by copper phthalocyanine, Examples thereof include 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 are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, a metal layer represented by strontium, aluminum, or the like. And 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. In the present invention, the electron injection layer is preferably a very thin film, and although depending on the constituent material, the layer thickness is preferably in the range of 1 nm to 10 μm.

(Hole transport layer)
The layer thickness of the hole transport layer of another light-emitting unit is preferably 20 nm or more than the thickness of the hole transport layer of the light-emitting unit disposed at the position closest to the transparent electrode on the light emission side. Thereby, when the intermediate electrode functions as an anode, it is considered that silver ions contained in the intermediate electrode layer are prevented from diffusing up to the light emitting layer, thereby suppressing the occurrence of local electric field concentration. The hole transport layer is composed of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Moreover, a positive hole transport layer can be provided in single layer or multiple 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, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, and thiophene oligomers.

  As the hole transport material, those described above can be used, but porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can be used, and in particular, aromatic tertiary amine compounds can be used. preferable.

  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 (abbreviation: 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 -Tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, '-Di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) c Audriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N- Examples include diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4′-N, N-diphenylaminostilbenzene, N-phenylcarbazole and the like. Further, those having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] Biphenyl (abbreviation: NPD), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) in which triphenylamine units described in JP-A-4-308688 are linked in a three star burst type ) -N-phenylamino] triphenylamine (abbreviation: MTDATA).

  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, these materials are preferably used from the viewpoint of obtaining a light-emitting element with higher efficiency.

  For the hole transport layer, known methods such as vacuum deposition, spin coating, casting, printing including ink jet, and LB (Langmuir Brodget, Langmuir Broadgett) are used as the hole transport material. Thus, it can be formed by thinning. Although there is no restriction | limiting in particular about the layer thickness of a positive hole transport layer, Usually, about 5 nm-5 micrometers, Preferably it is the range of 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Moreover, p property can also be made high by doping the material of a positive hole transport layer with an impurity. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175 and J.P. Appl. Phys. 95, 5773 (2004), and the like.

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

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

  In the electron transport layer having a single-layer structure and the electron transport layer having a multilayer structure, an electron transport material (also serving as a hole blocking material) constituting a layer portion adjacent to the light emitting layer is used as an electron transporting material. What is necessary is just to have the function to transmit. 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. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the 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 can also be used as a material for the electron transport layer. it can. Furthermore, a polymer material in which these materials are introduced into a polymer chain, or a polymer material having these materials as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (abbreviation: 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 (abbreviation: Znq), etc. and the central metal of these metal complexes A metal complex replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as a material for the electron transport layer.

  In addition, metal-free or metal phthalocyanine or those having terminal ends substituted with alkyl groups or sulfonic acid groups can be preferably used as the material for the electron transport layer. In addition, distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the material of the electron transport layer. Like the hole injection layer and the hole transport layer, n-type-Si, n-type-SiC, etc. These inorganic semiconductors can also be used as a material for the electron transport layer.

  The electron transport layer 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 inkjet method, and an LB method. Although there is no restriction | limiting in particular about the layer thickness of an electron carrying layer, Usually, about 5 nm-5 micrometers, Preferably it exists in the range of 5-200 nm. The electron transport layer may have a single structure composed of one or more of the above materials.

  In addition, the electron transport layer 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 and J.P. Appl. Phys. 95, 5773 (2004), and the like. Furthermore, it is preferable to contain potassium, a potassium compound, etc. in an electron carrying layer. As the potassium compound, for example, potassium fluoride can be used. Thus, by increasing the n property of the electron transport layer, an organic EL element with lower power consumption can be obtained.

  Further, as the material (electron transporting compound) of the electron transport layer, the same material as that constituting the intermediate layer described above may be used. This is the same for the electron transport layer that also serves as the electron injection layer, and the same material as that for the intermediate layer described above may be used.

(Blocking layer)
The blocking layer (hole blocking layer and electron blocking layer) is a layer provided as necessary in addition to the constituent layers of the light emitting unit 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). Hole blocking (hole block) layer and the like.

  The hole blocking layer has a function of an electron transport layer 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 an electron carrying layer can be used as a hole-blocking layer as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

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

[Second electrode]
The second electrode 6 is an electrode film that functions to supply holes to the second light emitting unit 3B or the third light emitting unit 3E, and a metal, an alloy, an organic or inorganic conductive compound, or a mixture thereof is used. . Specifically, gold, 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 Oxide semiconductors such as ₂ and SnO ₂ .

  The second electrode 6 can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering. The sheet resistance as the second electrode 6 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 the case where the organic EL elements 100 and 200 are of the double-sided emission type in which the emitted light L is also extracted from the second electrode 6, the second electrode 6 having good light transmittance may be selected and configured. In this case, the above-described base layers 41, 42 and 43 may be provided on the surface of each light emitting unit 3 on the second electrode 6 side.

[Sealing member]
Examples of the sealing means used for sealing the organic EL elements 100 and 200 include a method of bonding the sealing member, the second electrode 6 and the transparent substrate 1 with an adhesive.

  As a sealing member, it should just be arrange | positioned so that the display area of the organic EL elements 100 and 200 may be covered, and it may be concave plate shape or flat plate shape. Further, transparency and electrical insulation are not particularly limited.

  Specifically, a glass plate, a polymer plate, a film, a metal plate, a film, etc. are mentioned. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include 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.

As the sealing member, since the organic EL elements 100 and 200 can be thinned, a polymer film and a metal film can be preferably used. Further, the polymer film has a water vapor transmission rate of 1 × 10 ⁻³ g / m ² .multidot.m at a temperature of 25 ± 0.5 ° C. and a relative humidity of 90 ± 2% RH measured by a method according to JIS K 7129-1992. The oxygen permeability measured by a method according to JIS K 7126-1987 is preferably 1 × 10 ⁻³ ml / m ² · 24 h · atm (1 atm is 1.01325 × 10 ⁵ a Pa) equal to or lower than a temperature of 25 ± 0.5 ° C., water vapor permeability at a relative humidity of 90 ± 2% RH is preferably not more than ^{1 × 10 -3 g / m 2} · 24h.

  For processing the sealing member into a concave shape, sandblasting or chemical etching is used. Specific examples of adhesives include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. An agent can be mentioned. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since the organic EL elements 100 and 200 may be deteriorated by heat treatment, an adhesive that can be adhesively cured from room temperature to 80 ° C. is preferable. Further, a desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing member may use commercially available dispenser, and may print like screen printing.

  In addition, the second electrode 6 and the light emitting unit 3 are covered outside the second electrode 6 on the side facing the transparent substrate 1 with the light emitting unit 3 interposed therebetween, and an inorganic or organic layer is formed in contact with the transparent substrate 1. Thus, a sealing film can be suitably used. In this case, the material for forming the sealing film may be any material that has a function of suppressing the intrusion of moisture, oxygen, or the like that degrades the organic EL elements 100 and 200, such as silicon oxide, silicon dioxide, and silicon nitride. Etc. can be used. Furthermore, in order to improve the brittleness of the sealing film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, 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.

  In the gap between the sealing member and the display area of the organic EL elements 100 and 200, an inert gas such as nitrogen or argon, an inert liquid such as fluorinated hydrocarbon, or silicon oil is injected in the gas phase and the liquid phase. It is preferable. Further, the gap between the sealing member and the display area of the organic EL elements 100 and 200 can be evacuated, or a hygroscopic compound can be sealed in the gap.

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

《Light extraction》
The organic EL elements 100 and 200 emit light inside a layer having a refractive index higher than that of air (refractive index of about 1.6 to 2.1), and light of about 15% to 20% of light generated in the light emitting layer. It is generally said that it can only be taken out. This is because light incident on the interface (the interface between the transparent substrate 1 and air) at an angle θ equal to or greater than the critical angle causes total reflection and cannot be extracted outside the device. This is because the light undergoes total reflection between the light and the light, and the light is guided through the transparent electrode or the light emitting layer.

  As a technique for improving the light extraction efficiency, for example, a method of forming irregularities on the substrate surface to prevent total reflection at the interface between the substrate and the air (for example, US Pat. No. 4,774,435), condensing light on the substrate. A method for improving the efficiency by imparting a property (for example, Japanese Patent Laid-Open No. Sho 63-314795), a method for forming a reflective surface on the side surface of the element (for example, Japanese Patent Laid-Open No. Hei 1-220394), a substrate and light emission A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between bodies (for example, Japanese Patent Application Laid-Open No. Sho 62-172691), and lowering the refractive index between the substrate and the light emitter than the substrate. And a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside) (for example, Japanese Patent Laid-Open No. 2001-202827). 11- No. 83751 publication), and the like.

  In the present invention, these methods can be used in combination with the organic EL elements 100 and 200 of the present invention. A flat layer having a lower refractive index than the transparent substrate 1 is provided between the transparent substrate 1 and the light emitting unit 3. A method of introducing or a method of forming a diffraction grating between any layers of the transparent substrate 1, the transparent electrode (first electrode 2) and the light emitting unit 3 (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a low refractive index medium is formed between the transparent electrode (first electrode 2) and the transparent substrate 1 with a thickness longer than the wavelength of light, the light emitted from the transparent electrode (first electrode 2) The lower the refractive index, the higher the extraction efficiency to the outside.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate 1 is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less, more preferably 1.35 or less. .

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low-refractive index layer is reduced when the thickness of the low-refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the transparent substrate 1.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction or second-order diffraction. The light that cannot be emitted due to total reflection between layers is diffracted by introducing a diffraction grating into any layer or medium (inside the transparent substrate 1 or the transparent electrode). , Trying to extract light out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  The position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate 1 or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

  In addition, the organic EL elements 100 and 200 of the present invention are processed so as to provide, for example, a structure on the microlens array on the light extraction side of the transparent substrate 1 or combined with a light collecting sheet described later. Thus, by focusing light in a specific direction, for example, in the front direction with respect to the element light emitting surface, the luminance in the specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, a triangle stripe having a vertex angle of 90 degrees and a pitch of 50 μm may be formed on the substrate, the vertex angle may be rounded, and the pitch may be changed randomly. Or other shapes.

  In addition, the light extraction film not only controls the light emission angle but also scatters different emission colors in the surface direction region to obtain white light emission. You may use a light-diffusion plate and a film together with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<Application>
The organic EL elements 100 and 200 of the present invention can be used as display devices, displays, and various light sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Etc. Although it is not limited to this, it can be effectively used as a backlight of a liquid crystal display device combined with a color filter and a light source for illumination. When used as a backlight of a display in combination with a color filter, it is preferably used in combination with a light collecting sheet in order to further increase the luminance.

  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 "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

[Example 1]
<< Sample preparation >>
[Organic EL element No. 1: Number of light emitting units 2]
An example of sample preparation of the organic EL element 100 having two light emitting units is shown in organic EL element No. 1 will be used for explanation.
(Preparation of transparent substrate)
As the transparent substrate 1, a transparent alkali-free glass having a thickness of 150 μm was used.
A UV curable organic / inorganic hybrid hard coat material OPSTAR Z7501 (manufactured by JSR Corporation) was applied to the easy adhesion surface of the transparent substrate 1 with a wire bar so that the film thickness after drying was 4 μm. After drying at 80 ° C. for 3 minutes, it was cured by irradiation with 1.0 J / cm ² using a high-pressure mercury lamp in an air atmosphere.

(Formation of gas barrier layer)
Next, a gas barrier layer having a thickness of 300 nm was formed on the thin film layer according to the following excimer method.

<Preparation of coating solution for forming polysilazane layer>
A 10 mass% dibutyl ether solution of perhydropolysilazane (Aquamica NN120-10, non-catalytic type, manufactured by AZ Electronic Materials Co., Ltd.) was used as a coating liquid for forming a polysilazane layer.

<Formation of polysilazane layer>
The prepared polysilazane layer-forming coating solution is applied with a wireless bar so that the (average) layer thickness after drying is 300 nm, and treated for 1 minute in an atmosphere at a temperature of 85 ° C. and a relative humidity of 55%. The polysilazane layer was formed by drying and further holding in an atmosphere of a temperature of 25 ° C. and a relative humidity of 10% (dew point temperature −8 ° C.) for 10 minutes to perform dehumidification.

<Formation of gas barrier layer: Silica conversion of polysilazane layer by ultraviolet light>
Next, the following ultraviolet device was installed in the vacuum chamber for the polysilazane layer formed above, and the pressure in the device was adjusted to carry out a silica conversion treatment.

<Ultraviolet irradiation device>
Apparatus: M.com Co., Ltd. excimer irradiation apparatus MODEL: MECL-M-1-200
Irradiation wavelength: 172 nm
Lamp filled gas: Xe
<Reforming treatment conditions>
The substrate on which the polysilazane layer fixed on the operation stage was formed was modified under the following conditions to form a gas barrier layer.

Excimer lamp light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 1mm
Stage heating temperature: 70 ° C
Oxygen concentration in the irradiation device: 1.0%
Excimer lamp irradiation time: 5 seconds

(Formation of the first electrode)
On the transparent substrate 1, an ITO (Indium Tin Oxide) film having a thickness of 150 nm was formed by a sputtering method and patterned by a photolithography method to form a first electrode 2 (anode). The pattern was formed as a pattern having a light emitting area of 50 mm square.

(Formation of first light emitting unit)
Subsequently, after reducing the pressure to 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the compound HAT-CN was deposited at a deposition rate of 0.1 nm / second while moving the substrate, and 10 nm hole injection was performed. A layer was provided.

  Next, Compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide a 40 nm hole transport layer (HTL). A heating boat containing the host material H-1, and phosphorescent compound A-3 (blue light emitting dopant), compound A-1 (green light emitting dopant), and compound A-2 (red light emitting dopant), respectively. A 30 nm light emitting layer having the host material H-1 and a blue phosphorescent compound was formed on the hole transport layer. Under the present circumstances, the electricity supply of the heating boat was adjusted so that vapor deposition rate might become host compound H-1: compound A-3 (blue light emission dopant) = 93: 7 (volume ratio).

  Thereafter, Compound ET-1 was vapor-deposited to form a 20 nm electron transport layer.

(Formation of underlayer and intermediate electrode layer)
Next, the sample formed up to the first light emitting unit 3A was fixed to a substrate holder of a commercially available vacuum deposition apparatus and attached to a vacuum chamber of the vacuum deposition apparatus.

  As the nitrogen atom-containing compound, Exemplified Compound No. 10 was placed in a resistance heating boat made of tantalum. These substrate holder and heating boat were attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, silver (Ag) was put into the resistance heating boat made from tungsten, and it attached in the 2nd vacuum chamber.

After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the resistance heating boat of the first vacuum chamber was energized and heated. Next, the resistance heating boat of the second vacuum tank was energized and heated to form an intermediate electrode layer 4A containing silver (Ag) with a thickness of 10 nm.

(Formation of second light emitting unit)
On the intermediate electrode layer 4A, in the same manner as the formation of the first light emitting unit, using a commercially available vacuum deposition apparatus, after reducing the pressure to 1 × 10 ⁻⁴ Pa, the compound HAT-CN was moved while moving the substrate. Vapor deposition was performed at a deposition rate of 0.1 nm / second, and a 10 nm hole injection layer was provided.

Next, the second light emitting unit 3B was formed in the same manner as the first light emitting unit 3A. Specifically, Compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide an 80 nm hole transport layer (HTL). A 30 nm light emitting layer having the host material H-1, a green phosphorescent compound and a red phosphorescent compound was formed on the hole transport layer. At this time, the heating boat was adjusted so that the deposition rate was host compound H-1: compound A-1 (green light emitting dopant): compound A-2 (red light emitting dopant) = 89: 10: 1 (volume ratio). The energization was adjusted.
Thereafter, Compound ET-1 was vapor-deposited to form a 20 nm electron transport layer.

(Formation of second electrode)
Next, after forming potassium fluoride (KF) with a thickness of 2 nm, aluminum was vapor-deposited with a thickness of 110 nm to form a second electrode 6 (cathode).

(Sealing)
Using a sealing member in which a sample prepared up to the second electrode 6 (cathode) is coated with a thermosetting liquid adhesive (epoxy resin) at a thickness of 30 μm on one side of an aluminum foil having a thickness of 100 μm. The adhesive surface of the sealing member and the layer surface of the second electrode 6 of the organic EL element 100 are continuously arranged so that the ends of the extraction electrodes of the first electrode 2 and the second electrode 6 of the organic EL element 100 come out. The organic EL element 100 having a two-layer structure in which the sealed light emitting unit 3 was formed was bonded by a dry lamination method.

  The sealing step is performed under atmospheric pressure and in a nitrogen atmosphere with a moisture content of 1 ppm or less, in accordance with JIS B 9920, with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or less, and an oxygen concentration of 0.8 ppm or less. At atmospheric pressure. In addition, the description regarding formation of the lead-out wiring from an anode and a cathode is abbreviate | omitted.

  In addition, the said compound HAT-CN, HT-1, compound A-1 to 3, compound H-1, and compound ET-1 are the compounds shown below.

  In addition, organic EL element No. 2, 3, 7, 9, 11, 13, and 15 to 23, the conditions shown in Table 1 (the HTL layer thickness and emission color of the light emitting units 3A and 3B, the compound used for the underlayer 41 of the intermediate electrode layer 4A, According to the material and layer thickness and the total thickness of the organic functional layer), the organic EL element No. An organic EL element was produced in the same manner as in 1. Organic EL element No. 8, 10, 12, and 14, except that the second electrode 6 was replaced with Al and Ag was used, the organic EL element No. In the same manner as in Example 1, organic EL elements were produced according to the conditions in Table 1. In addition, organic EL element No. For 4 to 6, in the preparation of the above-described sample, an ITO film is formed by sputtering instead of forming the intermediate electrode layer 4A made of silver (Ag). At this time, in order to prevent damage to the first light emitting unit 3A, an intermediate electrode layer made of ITO having a layer thickness of 120 nm was formed at a deposition rate of 0.01 nm / sec. Except for this, an organic EL device was produced in the same procedure according to the conditions shown in Table 1. The organic EL element No. For 1 to 23, a transparent non-alkali glass is commonly used as the transparent substrate 1, and an ITO film is formed on the transparent substrate 1 as the first electrode 2 (anode) by sputtering. .

[Organic EL element No. 30: 3 light emitting units]
(Preparation of substrate)
Organic EL element No. A transparent substrate 1 similar to that used for manufacturing 1 was prepared.

(Formation of gas barrier layer)
Next, the organic EL element No. The gas barrier layer was formed by the same method as the gas barrier layer forming method (excimer method) used in the production of 1.

(Formation of the first electrode)
An ITO film having a thickness of 150 nm was formed on the transparent substrate 1 by a sputtering method and patterned by a photolithography method to form a first electrode 2 (anode). The pattern was formed as a pattern having a light emitting area of 50 mm square.

(Formation of first light emitting unit including red light emitting layer)
Subsequently, after reducing the pressure to 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the compound HAT-CN was deposited at a deposition rate of 0.1 nm / second while moving the substrate, and 10 nm hole injection was performed. A layer was provided.

  Next, Compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide a 40 nm hole transport layer (HTL). The heating boat containing the host material H-1 and the heating boat containing the compound A-2 (red light emitting dopant) are energized independently to emit 30 nm red light emitted from the host material H-1 and the red light emitting dopant. A layer was deposited on the hole transport layer. Under the present circumstances, the electricity supply of the heating boat was adjusted so that vapor deposition rate might become host compound H-1: compound A-2 (red light emission dopant) = 95: 5 (volume ratio).

  Thereafter, Compound ET-1 was deposited to a layer thickness of 20 nm to form an electron transport layer.

(Formation of underlayer and second intermediate electrode layer)
Next, the sample formed up to the first light emitting unit 3C was fixed to a substrate holder of a commercially available vacuum deposition apparatus and attached to a vacuum chamber of the vacuum deposition apparatus.

  As the nitrogen atom-containing compound, Exemplified Compound No. 10 was placed in a resistance heating boat made of tantalum. These substrate holder and heating boat were attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, silver (Ag) was put into the resistance heating boat made from tungsten, and it attached in the 2nd vacuum chamber.

After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the resistance heating boat of the first vacuum chamber was energized and heated. Next, the resistance heating boat of the second vacuum tank was energized and heated to form a first intermediate electrode layer 4B containing silver (Ag) with a thickness of 10 nm.

(Formation of second light emitting unit having green light emitting layer)
Subsequently, after reducing the pressure to 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the compound HAT-CN was deposited at a deposition rate of 0.1 nm / min while moving the substrate provided with the first intermediate electrode layer 4B. Vapor deposition was performed in seconds, and a 10 nm hole injection layer was provided.

  Next, Compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide an 80 nm hole transport layer (HTL). The heating boat containing the host material H-1 and the heating boat containing the phosphorescent compound A-1 (green light emitting dopant) are independently energized, and 30 nm comprising the host material H-1 and the green light emitting dopant. The green light emitting layer was formed on the hole transport layer. Under the present circumstances, the electricity supply of the heating boat was adjusted so that vapor deposition rate might become host compound H-1: compound A-1 (green light emission dopant) = 90: 10 (volume ratio).

  Thereafter, Compound ET-1 was deposited to a layer thickness of 20 nm to form an electron transport layer.

(Formation of underlayer and second intermediate electrode layer)
Next, the sample formed up to the second light emitting unit 3D was fixed to a substrate holder of a commercially available vacuum deposition apparatus and attached to a vacuum chamber of the vacuum deposition apparatus.

  As the nitrogen atom-containing compound, Exemplified Compound No. 10 was placed in a resistance heating boat made of tantalum. These substrate holder and heating boat were attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, silver (Ag) was put into the resistance heating boat made from tungsten, and it attached in the 2nd vacuum chamber.

After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the resistance heating boat of the first vacuum chamber was energized and heated. Next, the resistance heating boat of the second vacuum tank was energized and heated to form a second intermediate electrode layer 4C containing silver (Ag) with a thickness of 10 nm.

(Formation of a third light emitting unit having a blue light emitting layer)
Subsequently, after reducing the pressure to 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the compound HAT-CN was deposited at a deposition rate of 0.1 nm / second while moving the substrate, and 10 nm hole injection was performed. A layer was provided.

  Next, Compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide an 80 nm hole transport layer (HTL). A heating boat containing the host material H-1 and a thermal boat containing the phosphorescent compound A-3 (blue light emitting dopant) are energized independently to form 30 nm comprising the host material H-1 and the blue light emitting dopant. The blue light emitting layer was formed on the hole transport layer. Under the present circumstances, the electricity supply of the heating boat was adjusted so that vapor deposition rate might become host compound H-1: compound A-3 (blue light emission dopant) = 93: 7 (volume ratio).

  Then, the compound ET-1 was vapor-deposited with a layer thickness of 20 nm to provide an electron transport layer, thereby forming a third light emitting unit 3E having a blue light emitting layer.

(Formation and sealing of the second electrode)
Subsequently, organic EL element No. 1 is formed and sealed on the third light emitting unit 3E, so that the light emitting unit 3 has a three-layer structure. 30 was produced.

  The organic EL element No. The conditions shown in Table 2 for 24 to 27, 32, and 34 to 51 (HTL layer thickness and emission color of the light emitting unit, materials and layer thicknesses used for the first intermediate electrode layer 4B and the second intermediate electrode layer 4C, and organic functions) In accordance with the total layer thickness), an organic EL device was similarly produced. Organic EL element No. 31, 33, and 53 to 56, except that the second electrode 6 was replaced with Al and Ag was used, except that the organic EL element No. In the same manner as in 30, organic EL elements were produced according to the conditions in Table 2. In addition, organic EL element No. For 28 and 29, instead of forming the intermediate electrode layer 4B and the second intermediate electrode layer 4C made of silver (Ag) in the preparation of the above-described sample, an ITO film was formed by sputtering. ing. At this time, in order to prevent damage to the first light emitting unit 3C and the second light emitting unit 3D, an intermediate electrode layer made of ITO having a layer thickness of 120 nm was formed at a film formation rate of 0.01 nm / sec. Except for this, an organic EL device was produced in the same procedure according to the conditions shown in Table 2. The organic EL element No. Also for 24-56, a transparent non-alkali glass is commonly used as the transparent substrate 1, and an ITO film is formed on the transparent substrate 1 as the first electrode 2 (anode) by sputtering. . In addition, organic EL element No. The base compound 42 of the first intermediate electrode layer 4B of Nos. 24-56 and the base layer 43 of the second intermediate electrode layer 4C are commonly used for the example compound Nos. 10 is used.

<< Evaluation of organic EL elements >>
[Power efficiency]
Using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics Co., Ltd.), the organic EL element No. constituting each lighting device. The front luminance and luminance angle dependency of each of the light emitting units 3 of 1 to 56 were measured, and the power efficiency at the front luminance of 1000 cd / m ² was obtained. In addition, evaluation of power efficiency is organic EL element No.2. The power efficiency of 7 is shown as a relative value with 100 as the power efficiency. The larger the value, the better the power efficiency.

[Luminescence life]
Under an environment of 23 ° C. and 50% RH, each light emitting unit 3 emits light continuously under a constant current condition of 50 mA / cm ² , and an initial luminance is obtained using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). The time (half-life: τ1 / 2) required to obtain half the brightness of was measured. The evaluation of the light emission lifetime is based on the organic EL element No. A relative value with a half-life (time) of 7 as 100 is shown. The larger the value, the longer the light emission lifetime.

[Light distribution characteristics]
Organic EL Study Group (2012) 14th Regular Meeting Proceedings Organic EL Element No. 1 using the viewing angle dependency evaluation method described in p11-12. Each light emitting unit 3 of 1 to 56 was evaluated. The evaluation results are as follows. The viewing angle dependence (light distribution) of 7 was set to B, and if it was better than that, it was determined to be A, and C that was slightly inferior but showed sufficient performance. In addition, organic EL element No. With respect to the viewing angle dependency (light distribution) of 7, the performance was judged as D if the performance was inferior, and as E if the performance was extremely inferior.

<Summary>
As is clear from the results shown in Table 3, the organic EL elements 100 and 200 of the present invention having the configuration defined in the present invention are superior in power efficiency and light emission lifetime to the comparative example, and in addition, depend on the viewing angle. It can be seen that the property (light distribution) and durability are improved.

  In the organic EL elements 100 and 200 of the present invention, the layer thickness of the intermediate electrode layer 4 is in the range of 3 to 20 nm, and the plurality of light emitting units 3 emit blue light. The light emitting unit 3 that has at least one of a green light emitting layer that emits green light and a red light emitting layer that emits red light and that emits green light is disposed at a position closest to the transparent electrode on the light emission side The light emitting unit 3 that emits the light having the longest wavelength among the light emitting units 3 is disposed between the two intermediate electrode layers 4, and the plurality of organic functional layers constituting the light emitting unit 3 The total layer thickness is within the range of the number of light emitting units × (100 to 200) nm, and the intermediate electrode layer 4 is a base layer 41, 42 containing a compound represented by the general formula (1) or (2) or 43 adjacent to And the plurality of light emitting units 3 each have a hole transport layer as an organic functional layer, and the light emitting unit 3 disposed at a position closest to the transparent electrode on the light emission side has the hole transport layer The thickness of the hole transport layer of the light emitting unit 3 other than the thickness of the layer is 20 nm or more, and one of the pair of main electrodes is a transparent electrode functioning as an anode, It can be seen that the above effects are more exhibited by the configuration.

100, 200 Organic EL element 1 Transparent substrate 2 First electrode (main electrode)
3 (3A, 3B, 3C, 3D, 3E) Light-emitting unit 4 (4A, 4B, 4C) Intermediate electrode layers 41, 42, 43 Underlayer 6 Second electrode (main electrode)

Claims (8)

An organic electroluminescent device comprising at least two light emitting units and an intermediate electrode layer disposed between the light emitting units between a pair of main electrodes, each of which is a transparent electrode,
(1) The light emitting unit has a plurality of organic functional layers including a light emitting layer,
(2) Among the intermediate electrode layers, at least one intermediate electrode layer is a conductive layer containing silver as a main component,
(3) Among the light emitting layers, a light emitting unit that emits light having the shortest wavelength is disposed at a position farthest from the transparent electrode on the main light emitting side of the organic electroluminescence element. Luminescence element.   The organic electroluminescence device according to claim 1, wherein the thickness of the intermediate electrode layer is in the range of 3 to 20 nm. The plurality of light emitting units have at least one light emitting layer among a blue light emitting layer that emits blue light, a green light emitting layer that emits green light, and a red light emitting layer that emits red light,
3. The organic electroluminescence element according to claim 1, wherein the light emitting unit that emits the green light is disposed at a position closest to the transparent electrode on the light emitting side. 4.   4. The light-emitting unit that emits light having the longest wavelength among the light-emitting units is disposed between two intermediate electrode layers. 5. Organic electroluminescence device.   5. The total thickness of the plurality of organic functional layers constituting the light emitting unit is in the range of the number of light emitting units × (100 to 200) nm. 5. The organic electroluminescent element of description. The said intermediate electrode layer has a base layer containing the compound represented by the following general formula (1) or (2), The organic as described in any one of Claim 1-5 characterized by the above-mentioned. Electroluminescence element.

[In General Formula (1), Y ₁ represents a divalent linking group composed of an arylene group, a heteroarylene group, or a combination thereof. E _{1 to} E ₃₄ each represent —C (R ₁ ) ═ or —N═, and R ₁ represents a hydrogen atom or a substituent. At least one of E _{17 to} E ₂₅ and at least one of E _{26 to} E ₃₄ represent -N =. k1 and k2 represent an integer of 0 to 4, and k1 + k2 is an integer of 2 or more. In general formula (2), at least one of E ₁ and E ₂ is a nitrogen atom, at least one of E _{6 to} E ₁₀ is a nitrogen atom, and at least one of E _{11 to} E ₁₅ is Nitrogen atom. R ₁ represents a substituent. ] Each of the plurality of light emitting units has a hole transport layer as an organic functional layer, and
The layer thickness of the hole transport layer included in the other light-emitting unit is greater than the thickness of the hole transport layer included in the light-emitting unit disposed in the position closest to the transparent electrode on the light emitting side by 20 nm or more. The organic electroluminescence element according to claim 1, wherein the organic electroluminescence element is characterized in that:   8. The organic electroluminescent element according to claim 1, wherein one of the pair of main electrodes is a transparent electrode that functions as an anode. 9.

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