JPH0446312B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to an electroluminescent device (electroluminescent (EL) device) that performs electroluminescence.
In detail, it is a three-terminal EL element that has two independent light-emitting layers, and by controlling each of these layers individually, the color tone and intensity of light emission can be freely controlled, and also has sufficient brightness. Regarding. [Prior Art] EL devices generally have a structure in which a light-emitting layer containing a material with an EL function, that is, a material that emits light when placed in an electric field, is placed between two electrodes. A light-emitting element that generates light by applying a voltage between them to generate an electric field and converting electrical energy directly into light. Unlike conventional light emitting methods in which a gas electrically excited gives energy to a phosphor and causes it to emit light, it can be used in various shapes such as a thin panel shape, belt shape, cylindrical shape, etc.
It is attracting attention as a component of display media used to display lamps, lines, diagrams, images, etc., or as a material that has the potential to realize light-emitting bodies such as large-area panel lamps. Conventionally, inorganic metal materials such as ZnS containing Mn, Cu, or ReF ₃ (Re represents a rare earth) as an activator have been mainly used as materials with an EL function used in EL elements. Recently, EL devices using anthracene, pyrene, perylene, or their derivatives as materials for the light-emitting layer have been disclosed in Japanese Patent Application Laid-Open No. 58-172891, and various thin film forming methods have been used to form thin films with high precision. Organic compound materials that can be formed are attracting attention as materials for EL devices. The color of the light emitted by such an EL element is mainly
It is possible to control by appropriately selecting and combining the materials used for the light-emitting layer or by changing the intensity of the electric field. However, when an EL element is formed using materials that can form the light-emitting layer of currently known EL elements, the color and intensity of the emitted light are limited to some extent, and furthermore, in one EL element,
It has been almost difficult to greatly change the color of the emitted light, to subtly adjust the color tone, or to freely control the intensity of the emitted light. On the other hand, when a so-called thin film type EL element is manufactured by forming a thin film emitting layer using a thin film forming method such as vapor deposition using the above-mentioned inorganic metal material mainly composed of ZnS, the manufacturing cost becomes extremely high. There is a problem of storage, and it is extremely difficult to form a light-emitting layer made of a uniform thin film over a large area, so it has not been possible to mass-produce high-quality, large-area EL elements. On the other hand, as an EL element that is easy to mass-produce and is advantageous in terms of cost, the above-mentioned ZnS is mainly used.
An organic powder type EL element of an intrinsic EL type is known, in which a light-emitting layer is formed by dispersing an EL inorganic material in an organic binder. However, in this powder type EL element,
If the layer thickness is thin, defects such as pinholes are likely to occur in the light-emitting layer.There are structural limits to reducing the layer thickness of the light-emitting layer beyond a certain level in order to sufficiently improve the light-emitting characteristics. It is not possible to emit light, especially high brightness, and since the layer thickness is relatively thick, there have been problems such as increased power consumption in order to generate a stronger electric field. This is an improved powder type EL device with an intermediate dielectric layer made of vinylidene fluoride polymer in the light emitting layer of this powder type EL element to generate a stronger electric field.
Although a device is known from Japanese Patent Application Laid-Open No. 172891/1989, the device currently does not have satisfactory performance in terms of brightness, power consumption, etc. Even in this EL device using organic materials such as anthracene mentioned above, although the emissive layer is formed as a thin film with high precision, the density of carrier electrons or holes is very low, and carrier movement and At present, the probability of excitation of functional molecules due to recombination and the like is low, making it difficult to obtain efficient light emission, and the current situation is that it is not particularly satisfactory in terms of power consumption and brightness. [Objective of the Invention] The object of the present invention is to provide a novel structure that allows a single EL element to greatly change the color of emitted light, finely adjust the color tone, and freely control the intensity of emitted light. The purpose of this invention is to provide an EL device with a high quality. Another object of the present invention is to be able to appropriately select various materials for EL elements and combine them with the optimal thin film formation method to form a thin film, which has good luminous efficiency and can be driven at low voltage. The object of the present invention is to provide a novel EL element that provides sufficient brightness, is inexpensive, and has a structure that is easy to manufacture. [Structure of the Invention] That is, the electroluminescent device of the present invention comprises two electrode layers, at least one of which is transparent, two light-emitting layers provided between these two electrode layers, and a light-emitting layer provided between these two light-emitting layers. A three-terminal electroluminescent device comprising a transparent or semi-transparent electrode layer, at least one of the luminescent layers comprising:
A first compound containing an organic compound that is relatively electron-accepting.
a second layer containing an organic compound relatively exhibiting electron-donating properties, and a third layer having electrically insulating properties, and these layers are arranged in a direction from one of the electrode layers to the other. Once, the first layer, the second layer, and the third layer were repeatedly stacked in this order twice or more on the third layer, and then the first layer, the second layer
At least one of the layer and the third layer is
It is characterized by being composed of a monomolecular film or a monomolecular cumulative film. The three-terminal electroluminescent device (hereinafter simply EL) of the present invention
(referred to as an element) is a two-electrode element provided between a pair of electrode layers.
It has a structure in which two independent light-emitting layers are stacked, and each light-emitting layer can be individually controlled to change the color and intensity of the light emission as desired, and it is also possible to emit light with sufficient brightness. It is something that can be done. Hereinafter, an example of the EL element of the present invention will be explained in detail using the drawings. FIG. 1 is a schematic cross-sectional view of the EL element of the present invention. 1, 2, and 3 are electrode layers for generating an electric field by applying a voltage, and 1 is a transparent electrode layer from which light generated in the light emitting layer 4 and the light emitting layer 5 is combined and extracted. It is. 4 and 5 are EL
The light emitting layer 4 emits light due to the electric field generated by the electrode layers 1 and 3, and the light emitting layer 5 emits light due to the electric field generated by the electrode layers 2 and 3. Therefore, the electrode layer 3 serves as a common electrode for the light-emitting layers 4 and 5, and has the function of transmitting the light generated in the light-emitting layer 5 to the light-emitting layer 4 side. A semi-transparent layer may be used so that light is transmitted only to the fourth side. In the example of the EL device of the present invention shown in FIG. 1, the electrode layer 1 is provided as a transparent electrode among the electrode layer 1 and the electrode layer 2;
Only or both of these may be transparent. When only the electrode layer 2 is transparent, the electrode layer 3 is provided so as to have the function of transmitting at least light from the light emitting layer 4 to the light emitting layer 5 side, and both the electrode layer 1 and the electrode layer 2 are transparent. When transparent, the electrode layer 3 is provided so as to transmit light from the light-emitting layer 4 to the light-emitting layer 5 side, and also to transmit light to the opposite aroma. The light-emitting layer 4 and the light-emitting layer 5 may each have the same function, or may have different functions, such as emitting different colors and brightness. The basic structures of the light-emitting layer 4 and the light-emitting layer 5 included in the EL element of the present invention will be explained below. The light-emitting layers 4 and 5 consist of a first layer mainly containing an organic compound relatively exhibiting electron-accepting properties, a second layer mainly containing an organic compound relatively exhibiting electron-donating properties, and an electrically insulating layer. and a third layer having the following properties, and these layers are stacked by repeating the first layer, second layer, and third layer in this order two or more times on the third layer. It has a basic structure. and,
At least one layer among the first layer, second layer, and third layer of either the light-emitting layer 4 or the light-emitting layer 5 is a monomolecular film of an organic compound capable of forming the layer, or It is formed from a monomolecular cumulative film. That is, the light emitting layer of the EL element of the present invention is
Organic compounds that exhibit relative electron-accepting properties (hereinafter referred to as EA)
It has a structure in which a relatively electron-donating organic compound (hereinafter referred to as an ED compound) is placed in contact with each other, and when these compounds are placed in an electric field, These compounds have a luminescence effect based on the formation of an exciplex associated with the exchange of electrons between these compounds as a main luminescence source, and are suitable for efficiently forming such an exciplex with the generation of an electric field. It has a structure. An example of the light emitting layers 4 and 5 having such a structure is shown in the schematic cross-sectional view of FIG. 25 and 26 are electrode layers for generating an electric field by applying a voltage, and 20 is an EL layer.
It is a light-emitting layer that has a function. Among the electrode layers shown in FIG. 2, the electrode layer 25 corresponds to the electrode layer 3 of the EL element of the present invention shown in FIG.
This corresponds to electrode layer 1 or 2 of the EL element, respectively. The light-emitting layer 20 includes a first layer 21-1, 21-2, a second layer 22, and a third layer 23-1, 23-3 laminated on both the upper and lower ends and functioning as an insulating layer.
-1, 22-2 and the third layer 23-2 are alternately stacked to form a multilayer structure. In addition, in the case of a light-emitting layer having a monomolecular film or a monomolecular cumulative film, the first layer 21-1, 21-2, the second layer
layers 22-1, 22-2 and a third layer 23-1,
At least one of the layers 23-2 and 23-3 is formed from a monomolecular film of an organic compound capable of forming the layer or a cumulative film thereof. The first layer 21-1 of the light-emitting layer contains a compound that can be an EA compound with respect to the above-mentioned ED compound mainly contained in the second layer 22-1, and directly The second layer 22-1 stacked in contact with each other was mainly contained in the first layer 21-1.
These first layer 21-1 and second layer 22-1 contain a compound that can be an ED compound with respect to an EA compound.
The interface 24-1 serves as a contact surface between the EA compound and the ED compound. First layer 21-2 and second layer 2
The relationship 2-2 is similar to this, and an interface 24-2 is uniquely formed by these layers. At these interfaces 24-1 and 24-2, when a voltage is applied to the electrodes 1 and 2 and an electric field is applied to the light emitting layer 3, the EA compound and the ED compound form a complex in an excited state. , when this exciplex returns to the ground state, excitation energy is generated as light from the complex, EA compound, and/or ED compound in the excited state. As described above, the main source of light emission in the EL element of the present invention is light emission at the interfaces 24-1 and 24-2. First layers 21-1, 21-2 and second layer 22- constituting the light emitting layer of the EL element of the present invention
1,22-2 contains a compound molecule that directly participates in the formation of a field-excited complex as shown below, or a compound molecule having as at least one functional part of the compound molecule. As for the arrangement of compound molecules directly involved in the formation of such an electric field excited complex in the light emitting layer 20, the following combinations can be cited as typical examples. (a) First layer 21-1, 21-2 and second layer 22
A compound molecule having an EL function (mainly emitting light) based on exciplex formation is arranged at each of -1 and 22-2. (b) Compound molecules having an EL function based on exciplex formation are arranged in the first layers 21-1 and 21-2, and molecules of compounds (ED compounds) that can serve as electron donors for these compound molecules are arranged in the first layers 21-1 and 21-2, respectively. 2 layers 22-1 and 22-2. (c) Compound molecules having an EL function based on exciplex formation are arranged in the second layers 22-1 and 22-2, and molecules of a compound (EA compound) that can act as an electron acceptor for these compounds are placed in the first layer 22-1 and 22-2, respectively. It is arranged in the layers 21-1 and 21-2. As the compound having the EL function based on the formation of an exciplex, an organic compound that has a high luminescence quantum efficiency, has a π-electron system that is susceptible to external perturbation, and is easily excited by an electric field is suitably used. Examples of such compounds include fused polycyclic aromatic hydrocarbons, p-terphenyl, 2,5-diphenyloxazole, 1,4-bis-(2-methylstyryl)-benzene, xanthine, coumarin,
Acridine, cyanine dye, benzophenone, phthalocyanine, metal complex of phthalocyanine, polyphyrin, metal complex of porphyrin, 8-hydroxyquinoline, metal complex of 8-hydroxyquinoline, ruthenium complex, rare earth complex, and derivatives of these compounds, and other than the above Among the heterocyclic compounds and their derivatives, aromatic amines, aromatic polyamines, and compounds with a quinone structure, compounds having an EL function based on exciplex formation can be mentioned.
One or more compounds that can become EA compounds and one or more kinds that can become ED compounds are selected and combined as desired, and thin film formation methods such as vapor deposition, CVD, and single-molecule accumulation methods described later are applied appropriately. In this way, a light-emitting layer having the above-described structure (a) of the first layer and the second layer can be formed. Furthermore, compounds that can serve as electron acceptors or electron donors for the above-mentioned compounds having an EL function based on exciplex formation include heterocyclic compounds other than the above-mentioned compounds and their derivatives, aromatic amines, and aromatic polyamines. , a compound having a quinone structure, tetracyanoquinodimethane, tetracyanoethylene, etc., and by appropriately selecting and combining the above-mentioned compounds and these compounds, the above-mentioned first layer and second layer can be formed. Layer composition (b) or
A light emitting layer having (c) can be formed. Note that the compounds that can form the functional moieties mentioned above may be compounds that have a function of emitting light that is not based on exciplex formation, and the light emission in the EL element of the present invention is caused by the The light emission is not limited to only at the interfaces 24-1 and 24-2 between the first layer 21 and the second layer.
-1, 21-2 and/or second layer 22-1,
It may also include a case where light is emitted within 22-2. In addition to the EA compound, the first layers 21-1 and 21-2 also contain EA compounds that increase the electric field excitation efficiency of the EA compound through electrochemical interaction with the EA compound.
Other components may be included to control the luminescent color, increase the strength of the first layer, improve adhesion with other layers, etc., and the second layer may also contain other components. Similarly, it may contain compounds other than ED compounds. Compounds other than these EA compounds and ED compounds also have EL
It may be something that has a function. Compounds that can increase the field excitation efficiency of EA compounds through electrochemical interaction with EA compounds or ED compounds include compounds that can act as electron acceptors or electron donors for EA compounds;
Compounds that can be incorporated into the ED compound and serve as electron acceptors or electron donors can be mentioned. Such compounds include compounds that have an EL function (mainly emit light) based on the formation of an exciplex described above, compounds that can act as electron donors or acceptors for the compound, and compounds that can act as electron donors or acceptors for the compound, and by transfer of excitation energy, At least one compound that can be a light emitter and a functional moiety of these compound molecules
When forming the first layer and the second layer, one or more of these compounds can be used as the main component of the first layer and the second layer. It can be appropriately selected and used depending on the compound (EA compound and ED compound). Such a compound may be added to the first layer and/or the second layer.
The amount to be mixed in the EA layer varies depending on the compounds used in the first layer and the second layer, and cannot be unconditionally specified, but usually, the amount of the EA compound added to the EA compound is an electron acceptor or an electron donor. Regarding the compound contained in the first layer that can act as an electron acceptor or electron donor for the EA compound, the amount is 10 mol% to 0.1 mol% for the EA compound, and the second layer that can act as an electron acceptor or electron donor for the ED compound
For compounds contained in the layer, 10 mol%~
It is estimated to be around 0.1 mol%. First layer 21-1, 21-2 and second layer 22
-1, 22-2 at least one layer,
When forming the layer as a monomolecular film or a monomolecular cumulative film of a compound capable of forming the layer, the so-called single-molecule cumulative method enables highly ordered molecular orientation and arrangement and easily forms an ultra-thin film layer. can be suitably applied. This single molecule accumulation method is based on the following principle. In other words, for example, in a molecule that has a hydrophilic part and a hydrophobic part, when the balance between the two (amphipathic balance) is maintained appropriately, many of these molecules will be hydrophilic and hydrophobic on the water surface. Form a monomolecular layer with the sexual part facing down. This monomolecular layer has the characteristics of a two-dimensional system, and when these molecules are sparsely dispersed, the two-dimensional ideal gas equation is expressed between the area A per molecule and the surface pressure Π.
ΠA=kT (k: Boltzmann constant, T: absolute temperature)
holds true, and these molecules form a "gas film." However, when A is made sufficiently small, the intermolecular interaction becomes stronger, and these molecules form a two-dimensional solid "condensation film (or solid film)." This condensed film can be transferred to the surface of a substrate such as glass, and an ultra-thin monomolecular film or a cumulative film thereof can be formed on the substrate. According to this method, the molecules forming the monolayer are arranged in such a way that, for example, almost all of the hydrophilic parts of the constituent molecules are oriented toward the substrate in a highly ordered manner.
It can be made uniform within one monolayer. Therefore, by making the first layer and/or the second layer of the EL element of the present invention a monomolecular film or a monomolecular cumulative film, the layer formed as a monomolecular film or a monomolecular cumulative film can be It becomes possible to arrange the functional portion, which is comprised of compound molecules directly involved in the formation of an exciplex, at a high density at the interface between the first layer and the second layer. Various solutions can be used as a solution for forming a single molecule in this single molecule accumulation method, and depending on the solution used, a well-balanced number of molecules having different affinity for the solution can be used. A monomolecular film can be formed by appropriately selecting a compound for forming a molecular film. Among such solutions for forming a monomolecular film, water or a solution containing water as a main component is preferably used because it is inexpensive, easy to handle, and safe. The structure of the light-emitting layer having a monomolecular film of the EL element of the present invention will be described below, taking as an example the case where a monomolecular accumulation method using water or a solution containing water as a main component is applied. Basically, the compound that can form the first layer and the second layer of the light-emitting layer of the EL device of the present invention is a compound that can form the above-mentioned functional portion or a compound that can function as a compound molecule. A compound having at least one sexual moiety. Among these compounds, compounds that can form a monomolecular film or a monomolecular cumulative film, for example, take a compound for forming a monomolecular film that has one functional moiety, depending on the position within the molecule that has the functional moiety. Therefore, as shown in the schematic diagram of the molecular structure in FIG. 3, (a) the functional part 31 is on the hydrophilic part 32 side,
- Figure 3a (b) The functional part 31 is on the hydrophobic part 33 side,
- Fig. 3b (c) Functional part 31 is located approximately midway between hydrophobic part 33 and hydrophilic part 32 - Broadly classified into three types as shown in Fig. 3c. Components of the hydrophilic portion 32 of these compounds include, for example, carboxyl groups and metal salts thereof;
Amine salts and esters, sulfonic acid groups and their metal salts and amine salts, sulfonamide groups, amide groups, amino groups, imino groups, hydroxyl groups, 4
grade amino group, oxyamino group, oxyimino group,
Diazonium group, guanidine group, hydrazine group,
Examples include a phosphoric acid group, a silicic acid group, and an aluminate group, and each of them can be used alone or in combination to constitute the hydrophilic portion 32 in the above compound. Further, as the constituent elements of the hydrophobic portion 33, linear or branched alkyl groups, olefinic hydrocarbons such as vinylene, vinylidene, and acetylene, fused polycyclic phenyl groups such as phenyl, naphthyl, and anthranyl, and biphenyl Hydrophobic groups such as chain polycyclic phenyl groups can be mentioned, and these can also constitute the hydrophobic moiety 33 in the above compound either alone or in combination. On the other hand, interfaces 24-1 and 24-2 between the first layer and the second layer of the light-emitting layer having a monomolecular film or a monomolecular cumulative film of the EL element of the present invention (portions where light is mainly emitted) The orientation and arrangement of the monolayer in
FIG. 4 is a schematic partial cross-sectional view of the vicinity of the interface 24-1 (in this figure, both the first layer and the second layer are formed from a monomolecular film consisting only of a compound having a functional portion). As shown, (1) a hydrophilic portion 32 having a functional portion 31 of molecules forming a monolayer of the first layer 21-1;
A hydrophilic portion 32' having a functional portion 31' of molecules forming a monolayer of the second layer 32-1 is oriented at the interface 24-1. - FIG. 4a (2) A hydrophobic portion 33 having a functional portion 31 of molecules forming a monolayer of the first layer 21-1;
A hydrophobic portion 33' having a functional portion 31' of molecules forming a monolayer of the second layer 22-1 is oriented at the interface 24-1. - FIG. 4b (3) a hydrophobic portion 33 having a functional portion 31 of molecules forming a monolayer of the first layer 21-1;
A hydrophilic portion 32' having a functional portion 31' of molecules forming a monolayer of the second layer 22-1 is oriented at the interface 24-1. - FIG. 4c (4) A hydrophilic portion 32 having a functional portion 31 of molecules forming a monomolecular film of the first layer 21-1;
Hydrophobic portions 33' having functional portions 31' of molecules forming a monolayer of the second layer 6-1 are oriented at the interface 24-1. - It can be basically divided into four patterns as shown in Figure 4d. Incidentally, in the example shown in FIG. 4, both the first layer and the second layer of the light-emitting layer having a monomolecular film are made of a monomolecular film, but as mentioned earlier, of course, Only one layer or only the second layer may be composed of a monomolecular film, and in such a case, the layer that is not a monomolecular film cannot be formed by a thin film forming method such as vapor deposition or CVD. It is provided as a thin film layer formed in this way. In order to form the interface pattern of the light-emitting layer as shown in FIG. 4, compounds belonging to types a and b of the monomolecular film forming compounds listed above are preferably used. Further, in order to form the above-mentioned interface pattern (1), it is preferable to use a compound belonging to the above-mentioned type a in the first layer and the second layer, and to form the above-mentioned interface pattern (2), It is preferable to use a compound belonging to type b in the first layer and the second layer. Furthermore, in order to form the above-mentioned interface pattern (3), it is preferable to use the compound belonging to the type a in the first layer and the compound belonging to the type b in the second layer, and form the above-mentioned interface pattern (3). In order to form 4), it is preferable to use a compound belonging to type b in the first layer and a compound belonging to type a in the second layer. In the example explained above, the first layer and the second layer are formed from a monomolecular film, but the first layer 5-1, 5-2 and/or the second layer 6-1 ，
Even when 6-2 is composed of a monomolecular cumulative film,
The interface between the first layer and the second layer 7-
What is necessary is to form a monomolecular film constituting 1 and 7-2. In addition, when the first layer 5-1, 5-2 and/or the second layer 6-1, 6-2 consists of a monomolecular cumulative film, each monomolecular film constituting the cumulative film is may be the same, or one or more of the monolayers may be different from the other monolayers. Furthermore, the structure of the monomolecular cumulative film due to the orientation state of the molecules forming each monolayer is the so-called Y type (between each film, a hydrophilic part and a hydrophilic part or a hydrophobic part and a hydrophobic part are mutually separated). Various types of structures are available, such as the X-type (a structure in which the hydrophobic part of each film faces the substrate side), the Z-type (a structure in which the hydrophilic part of each film faces the substrate side), and variations thereof. It can be a structure. Further, the monomolecular film included in the first layer or the second layer of the light emitting layer of the EL element of the present invention may be a multicomponent monomolecular film formed of two or more kinds of compounds. In such a case,
As explained above about the structure of the light emitting layer, a combination of two or more types of compounds having a functional moiety, or a compound having a functional moiety and a compound having a functional moiety but not having a functional moiety. It may be a combination with a compound that can control the electrochemical properties of the light-emitting layer, such as electronegativity, by interaction with the light-emitting layer, or it may further increase the strength of the monomolecular layer that makes up the light-emitting layer. , other components may be added to improve adhesion between each layer. The structure of such a monomolecular film or a monomolecular cumulative film depends on the desired electrical properties of the first layer or the second layer, that is, the structure of the compound forming the first layer or the second layer or An appropriate selection may be made depending on the combination of compounds, for example, monolayers made of compounds belonging to type a, b, or c of the monolayer-forming compounds are combined and accumulated to form a layer perpendicular to the surface direction of the monolayer. It is possible to control the potential curve of π electrons in various directions. Compounds that can be used to form the first layers 21-1, 21-2 and/or the second layers 22-1, 22-2 as a monomolecular film or a monomolecular cumulative film include Among the above-mentioned compounds capable of forming a hydrophilic moiety or compounds having one or more of these compounds, compounds having a good balance of hydrophilic moieties and hydrophobic moieties can be used as is for monolayer formation. It can be used as
If this is not the case, a hydrophilic group and/or a hydrophobic group such as those mentioned above can be newly introduced into the molecule to form a compound for forming a monomolecular film. Examples of such compounds include compounds represented by the following structural formulas. In addition, in the structural formula shown below, X and Y
represents a hydrophilic group as mentioned above, but when both of these exist in one molecule, it is sufficient that one of them is a hydrophilic group, and in such a case, the other one is hydrogen. Further, R represents a linear or side chain alkyl group having about 4 to 30 carbon atoms, preferably about 10 to 25 carbon atoms. Among these compounds, the compounds with structural formulas No. 1 to No. 35 are compounds that have an EL function based on the formation of an exciplex among the compounds that can form the functional moiety listed above, by combining them with hydrophobic groups and/or It is modified with a hydrophilic group to form a monomolecular film-forming compound.
The compounds with structural formulas No. 42 to No. 54 and No. 85 to No. 86 have a structure in which an alkyl chain is directly bonded to a functional moiety; The bond may be, for example, an ether bond, a bond via a carbonyl group, or the like. Third layer 23-1, 23-2, 23-3 which is another layer of the light emitting layer of the EL element of the present invention
is a layer having insulating properties, especially the third layer 23
-1 and 23-3 have the function of increasing the insulation of the capacitor structure of the EL element of the present invention, and the third layer 2
3-2 has a function of confining the movement of electrons within a necessary minimum area and emitting light by efficient exchange of electrons. These third layers can also be formed by a thin film formation method such as a vapor deposition method or a CVD method, or a single molecule accumulation method. When this third layer is formed by the monomolecular accumulation method, the general formula that allows formation of a monomolecular film with precise and uniform insulation properties is: CH ₃ − (CH ₂ ) _o -X, or (In the above formula, n is 10≦n≦30, and
are −COOH, −CONH ₂ , −COOR, −N ⁺ (CH ₃ ) ₃・
Cl- ^,

【formula】

One or more compounds represented by the following formula can be used as the material for forming the third layer. Furthermore, when forming by vapor deposition, one or more of the above compounds or inorganic compounds such as SiO ₂ can be used as the third layer forming material. When the third layer is formed as a monomolecular cumulative film, each monomolecular film may be the same, or one or more of each monomolecular film may be different from other monomolecular films. . In addition, until now, using Figures 2 and 3,
The EL element of the present invention having two interfaces formed by the layer and the second layer has been described.
The number of interfaces in the light emitting layer 20 of the EL element of the present invention is not limited to this, and may be three or more. The thickness of each layer forming the light-emitting layer 20 of the EL device of the present invention having the above structure varies depending on the number of interfaces the EL device has and the configuration of each layer itself. , 500 Å or less, preferably 200 Å or less, for the second layer, 500 Å or less,
Preferably less than 200 Å, for the third layer 500 Å
Å or less, preferably 200 Å or less, and the total layer thickness of the light emitting layer is 5000 μm or less, preferably 3000 μm or less
It is desirable that the thickness be Å or less in order to obtain a good light emission state even in low voltage driving. As described above, two layers having the same function are selected from the light emitting layer 20 having the structure explained using FIGS. 2 and 3 so that the EL element of the present invention has the desired EL function.
Alternatively, the EL element of the present invention can be formed by selecting two layers having different functions such as different emission colors and brightness as the light-emitting layer 4 and the light-emitting layer 5. Two electrode layers 1 and 2 of the EL element of the present invention
As mentioned above, at least one of the
It is provided as a transparent electrode for extracting light. When forming an electrode layer as a transparent electrode,
InO ₂ on a film or sheet such as PMMA, polyester, or a transparent substrate such as a glass plate.
SnO ₂ , indium tein oxide (ITO)
The light emitting layer can be formed by laminating these materials by a vapor deposition method or the like, or by directly laminating these materials on the light emitting layer. The electrode layer 3 is provided as a transparent electrode or as a translucent electrode that transmits light only in one direction in the thickness direction of the electrode layer. When the electrode layer 3 is provided as a transparent electrode, the light emitting layer 4 or the light emitting layer 5 formed using the transparent electrode forming material described above.
It should be formed on top. When the electrode layer 3 is provided as a semi-transparent electrode, a material such as ITO, Au, InO ₂ , SnO ₂ or the like is used, taking into account the direction of light transmission.
What is necessary is just to form it on the formed light emitting layer 4 or the light emitting layer 5. In addition, non-transparent electrode layers can be formed by thin plates made of materials that can form normal electrodes with sufficient conductivity, or by directly depositing Al, Ag, Au, etc. on a suitable substrate or on a light-emitting layer formed. It can be formed by laminating layers by a vapor deposition method or the like. The thickness of these electrode layers is approximately 0.01 μm to 0.3 μm,
Preferably it is about 0.05 μm to 0.2 μm. Note that the shape and size of the EL element of the present invention are as follows:
Various shapes can be formed as desired. For example, the substrate for forming the transparent electrode is used as a substrate for forming a light-emitting layer, and this substrate can be shaped like a plate, a belt, or a cylinder to form the desired shape. It can be the size. In addition, three electrode layers 1, 2, 3
may be patterned into various shapes as desired. In the EL element of the present invention having the above configuration,
For example, a direct current or an alternating current is applied between the two electrodes 1 and 3 and between the electrodes 2 and 3 of the EL element so that an electric field of about 1×10 ⁵ to 3×10 ⁶ is applied to each of the light emitting layers 4 and 5, for example. Alternatively, good light emission can be obtained through the transparent electrode 1 by applying a pulse voltage. In addition, two light emitting layers having different luminescent colors and brightness are used as the light emitting layer 4 and the light emitting layer 5, and the electrode 1,
The color and intensity of the light from the transparent electrode 1 can be varied over a wide range by independently controlling the voltage between the transparent electrode 1 and the voltage between the electrodes 2 and 3. Hereinafter, typical operations of the monomolecular accumulation method, typified by the Langmuir-Blodget method (LB method), applied to the formation of a monomolecular film or a monomolecular cumulative film having a light-emitting layer of the EL device of the present invention will be explained. An aqueous phase for forming a monomolecular film is provided in a water tank, and a clean substrate is immersed in the aqueous phase. Next, a predetermined amount of a solution of a monomolecular film-forming compound dissolved or dispersed in an appropriate solvent is spread into the aqueous phase,
This compound is deposited in the form of a film on the surface of the aqueous phase. At this time, in order to prevent this precipitate from freely diffusing on the water phase and spreading too much, a partition plate (or float) is provided to limit the area of development and control the state of aggregation of the membrane substance. Obtain a proportional surface pressure Π. Then, activate the partition plate to reduce the expansion area,
The surface pressure Π is gradually increased and set to a surface pressure Π suitable for forming a monomolecular film. Here, this surface pressure Π
When the previously immersed substrate is gently moved up and down in a direction perpendicular to the aqueous phase surface while maintaining the temperature, the monomolecular film is transferred onto the substrate as the substrate moves upward and downward. , a monomolecular cumulative film is formed. To transfer a monomolecular film onto a substrate, in addition to the vertical immersion method mentioned above, there are also horizontal attachment methods in which the substrate is brought into contact with the water phase horizontally while keeping it parallel to the surface, and a cylindrical substrate is rotated on the water surface. Various methods can be applied, such as a rotating cylinder method in which a monomolecular film is transferred to the surface of a substrate using a rotating cylinder method, or a method in which the substrate is extruded from a substrate roll into an aqueous phase. In the vertical dipping method, the orientation of the film-forming molecules is usually reversed between the substrate pulling process and the dipping process, so that a so-called Y-shaped film is formed. In addition, according to the horizontal deposition method, a monomolecular film with the hydrophobic groups facing the substrate side is formed, and when it is made into a cumulative film, the so-called
A mold film is formed. However, the orientation of such hydrophilic groups and hydrophobic groups can also be changed by surface treatment of the substrate. Furthermore, the PH of the aqueous phase when forming a monomolecular film by the monomolecular accumulation method, the type and amount of additives for adjusting the PH of the aqueous phase, the temperature of the aqueous phase, the rate of raising and lowering the substrate, or the surface. Operating conditions such as pressure may be appropriately selected depending on the type of monomolecular film-forming compound used, the characteristics of the film to be formed, and the like. The EL element of the present invention can be formed, for example, in the following manner using the single molecule accumulation method as described above and other thin film forming methods such as vapor deposition. First, a third layer having a desired configuration is formed using the third layer forming material described above on the substrate on which the transparent electrode layer is provided, and then the third layer is further formed on the substrate provided with the transparent electrode layer described above. Using a material capable of forming the second layer, a desired structure is laminated in this order on the first layer and the second layer on the previously formed third layer. Next, a third layer is laminated on this second layer,
Depending on the desired number of interfaces between the first layer and the second layer, the operation for forming the first layer to the third layer is repeated two or more times to form the light emitting layer 4. After the light-emitting layer 4 is formed in this way, a metal such as Au is laminated on the third layer located at the top of the light-emitting layer 4 by vapor deposition or the like to form a semi-transparent electrode layer 3. Form. Furthermore, a light emitting layer 5 is formed on the electrode layer 3 using the same material as the light emitting layer 4 or a different material in the same manner as in the formation of the light emitting layer 4, and finally, the light emitting layer 5 is
The EL element of the present invention can be formed by laminating a metal such as Al, Ag, or Au on the third layer by a vapor deposition method or the like. In addition, when the two electrodes are both transparent, the transparent electrode layer is formed using the above-mentioned material on the transparent substrate for forming the light emitting layers 4 and 5, and the transparent electrode layer is formed after the formation of the light emitting layer 5 is completed. All you have to do is laminate them. When forming the EL device of the present invention as described above, the first layer of the light emitting layer 4 and the light emitting layer 5,
Each layer of the second layer and the third layer is formed by a material for forming these layers and a thin film forming method adapted to these materials, and either one of the light emitting layer 4 and the light emitting layer 5 is formed as a monomolecular film formed by a monomolecular accumulation method or a multilayer structure having a monomolecular accumulation film. At that time, in the above operation, at least one of the first layer, second layer, and third layer of either the light-emitting layer 4 or the light-emitting layer 5 is processed by a single-molecule accumulation method. It can be formed using Further, the plurality of first layers having a light emitting layer of the EL element of the present invention may each have the same structure, and the structure of one or more of the plurality of first layers may be different from each other. The structure may be different from that of other first layers, and the same applies to the second and third layers. Further, an adhesive layer may be provided between each layer constituting the EL element of the present invention in order to improve the adhesiveness of each layer. Furthermore, the present invention
It is desirable that the EL element be provided with a protective structure to protect the element from the effects of moisture and oxygen in the air. The EL device of the present invention as described above has two light-emitting layers that can be controlled independently, and these light-emitting layers can be individually controlled to change the color of the emitted light,
It has become possible to subtly adjust the color tone and freely control the intensity of light emission. Furthermore, the light-emitting layer of the EL element of the present invention mainly emits light at the interface between two layers having different electrochemical properties, and moreover, a plurality of such interfaces are provided in the light extraction direction of the EL element. The device has a structure that allows the amount of light emitted per unit of light extraction surface to be significantly increased compared to conventional EL devices. In addition, in the EL element of the present invention, the composition of the two layers constituting the interface is changed for each interface with respect to the plurality of interfaces that mainly emit light, and these are combined to adjust the emitted light color etc. as desired. It has also become possible to control it accordingly. In addition to these, the light-emitting layer of the EL device of the present invention is mainly formed by combining an organic compound material and a thin film suitable for the material, and is a multilayer layer having a plurality of interfaces that emit light as described above. Despite the structure, the overall thickness of the light emitting layer is thinner, and an efficient light emitting state can be obtained even when driven at a low voltage, and sufficient brightness can be obtained. In particular, in a light emitting layer having a monomolecular film, the thickness of the entire light emitting layer can be further increased by forming at least one of the layers constituting the light emitting layer as a monomolecular film or a monomolecular cumulative film. Furthermore, when the light-emitting layer is formed as a monomolecular cumulative film, the layer thickness of the light-emitting layer can be made very thin, and the above effects can be further enhanced. Moreover, in the light-emitting layer of the EL element of the present invention, when the first layer and/or the second layer is formed of a monomolecular film or a monomolecular cumulative film, the light-emitting layer is directly involved in light emission. The functional part of the compound is
The present invention further provides light emission based on the formation of an exciplex that is highly ordered and precisely oriented and arranged toward the interface between the first layer and the second layer, and accompanied by more efficient transfer of electrons. Each layer of the light-emitting layer of an EL element can be easily formed as a thin film with high precision mainly from various organic compound materials, and in particular, the first layer when formed as a monomolecular film or a monomolecular cumulative film, The second layer or the third layer can be formed at approximately normal temperature and normal pressure, and heat-sensitive material compounds that cannot be used in vapor deposition methods etc. may also be used to form these layers. As a result, the EL device of the present invention has become an inexpensive and mass-producible EL device. In addition, even when the EL device of the present invention is formed as a large-area EL device, the light-emitting layer is formed with high accuracy, and it has good functionality even as a large-area EL device. The EL of the present invention will be described below using reference examples and examples.
The device will be explained in more detail. Reference Example 1 [Formation of Light Emitting Layers No. 1 and No. 2] An ITO layer with a thickness of 1500 Å was formed on a 50 mm square glass surface by sputtering, and this was used as a substrate for forming a light emitting layer. This substrate was placed in Langmuir-Trough4 manufactured by Joyce-Loebel at 4×10 ^-4 mol/
of CdCl ₂ in an aqueous phase whose pH was adjusted to 6.5. Next, add arachidic acid to chloroform 1x
0.5 ml of the solution dissolved at a concentration of 10 ^-3 mol/was developed on the aqueous phase. After evaporating chloroform from the surface of the water phase, the surface pressure of the water phase was reduced to 30dyne/cm.
arachidic acid in the form of a film was precipitated on the surface of the aqueous phase. Furthermore, while keeping the surface pressure constant, the substrate was gently pulled up at a speed of 2 cm/min across the water surface, and a third layer, a monomolecular insulating layer made of arachidic acid molecules, was placed on the electrode layer of the substrate. formed, which was pulled out of the aqueous phase and left to dry at room temperature for more than 30 minutes. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and the substrate on which the monomolecular insulating layer made of arachidic acid has been formed is again immersed in the aqueous phase, and then a new 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was developed on this aqueous phase, and the surface pressure was increased.
After adjusting to 30 dyne/cm, the substrate was gently pulled up at a speed of 2 cm/min in the direction across the water surface, and a monomolecular film made of the above compound molecules was formed as a second layer on the insulating layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Furthermore, the above compounds left on the surface of the water phase are completely removed, the substrate is immersed in the water phase, and a new one is added. 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was developed on this aqueous phase, and the surface pressure was increased.
After adjusting to 30 dyne/cm, the substrate was gently pulled up at a speed of 2 cm/min in the direction across the water surface, and a monomolecular film made of the above compound molecules was formed as a first layer on the second layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated 16 times, and finally the third layer is laminated to form a light emitting layer No. 1 having 16 interfaces between the first layer and the second layer. .
1 (layer thickness: approximately 1600 Å). Furthermore, the formation operation from the third layer to the second layer is
Light-emitting layer No. 2 having 12 interfaces between the first layer and the second layer was prepared in the same manner as above except that the procedure was repeated 12 times.
(layer thickness: about 1200 Å) was formed. Reference Example 2 [Formation of Light Emitting Layer No. 3] The same substrate as that used in Reference Example 1 was used in Reference Example 1.
It was immersed in the same aqueous phase for forming a monolayer as used in . Next, add arachidic acid to chloroform 1x
0.5 ml of the solution dissolved at a concentration of 10 ^-3 mol/was developed on the aqueous phase. After evaporating chloroform from the surface of the water phase, the surface pressure of the water phase was reduced to 30dyne/cm.
arachidic acid in the form of a film was precipitated on the surface of the aqueous phase. Furthermore, while keeping the surface pressure constant, the substrate was gently reciprocated vertically twice at a speed of 2 cm/min in the direction across the water surface. A layer of 3 was formed on the electrode layer of the substrate, and this was pulled out of the aqueous phase.
It was left to dry at room temperature for more than a minute. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and the substrate on which the monomolecular insulating layer made of arachidic acid has been formed is again immersed in the aqueous phase. 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was spread on the external aqueous phase, and the surface pressure was
After adjusting to 30dyne/cm, gently pull the board across the water surface at a speed of 2cm/min.
Furthermore, pulling down and pulling up was performed once each to form a first layer of three accumulated monomolecular films made of the above compound on the insulating layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Next, the above compounds left on the surface of the aqueous phase are completely removed, the substrate is immersed in the aqueous phase, and a new one is added. 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was developed on the aqueous phase, and the surface pressure was increased.
After adjusting to 30dyne/cm, gently pull the board across the water surface at a speed of 2cm/min.
Furthermore, pulling down and pulling up was performed once each, and a second layer consisting of three monomolecular films of the above compound was formed on the previously formed first layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated four times, and finally the third layer is further laminated to form a light-emitting layer having four interfaces between the first layer and the second layer. No. 3 (layer thickness: about 1100 Å) was formed. Reference Example 3 [Formation of Light Emitting Layer No. 4] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, add arachidic acid to chloroform 1x
0.5 ml of the solution dissolved at a concentration of 10 ^-3 mol/was developed on the aqueous phase. After evaporating chloroform from the surface of the water phase, the surface pressure of the water phase was reduced to 30dyne/cm.
was adjusted to precipitate a film of arachidic acid on the surface of the aqueous phase. Furthermore, while keeping the surface pressure constant, the substrate was gently pulled up at a speed of 2 cm/min across the water surface to form a monomolecular film of arachidic acid molecules on the electrode layer of the substrate, and this was removed from the water phase. It was pulled up to a room temperature and left to dry at room temperature for 30 minutes or more. This operation was repeated once again to form an insulating layer in which two arachidic acid monomolecular films were accumulated as a third layer. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and freshly added to chloroform. and

[Formula] at a ratio of 100mol:1mol, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
Spread 0.5 ml on this aqueous phase and increase the surface pressure.
After adjusting the temperature to 30 dyne/cm, the substrate on which the insulating layer made of arachidic acid was formed was gently immersed in the water phase again at a speed of 2 cm/min in the direction across the water surface of the water phase, and the above two types were added. A monomolecular film consisting of compound molecules was formed as a first layer on the insulating layer. Next, this substrate was pulled out of the water phase and again
It was left to dry at room temperature for more than a minute. Furthermore, the above compounds left on the surface of the aqueous phase were completely removed and freshly added to chloroform.

[Formula] and

[Formula] at a ratio of 100nol:1mol, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
Spread 0.5 ml on this aqueous phase and increase the surface pressure.
After adjusting to 30 dyne/cm, repeat the above first layer forming operation to form a second monomolecular film consisting of the above two types of compounds on the previously formed first layer.
Formed as a layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated 15 times, and finally the third layer is laminated to form a light emitting layer No. 1 having 15 interfaces between the first layer and the second layer. .
4 (layer thickness: about 1500 Å) was formed. Reference Example 4 [Formation of Light Emitting Layer No. 5] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, the operation for forming a monomolecular film made of arachidic acid in Reference Example 3 was repeated five times to form an insulating layer made of a five-layer cumulative film of monomolecular arachidic acid as a third layer. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and freshly added to chloroform. and

[Formula] at a ratio of 100 mol: 1 mol, the total amount of these is 1
0.5 ml of the solution dissolved at a concentration of ×10 ^-3 mol/was spread on this aqueous phase, and the surface pressure was
After adjusting the concentration to 30 dyne/cm, the substrate on which the monomolecular cumulative film insulating layer made of arachidic acid was formed was again placed in the water phase for 2 minutes in a direction across the water surface of the water phase.
It was gently immersed at a speed of cm/min, and further moved up and down to form a first layer, which was a stack of three monomolecular films made of the above two types of compound molecules, on the previously formed insulating layer. Next, pull this substrate out of the water phase and again for 30 minutes.
It was left to dry at room temperature for more than a minute. Furthermore, the above compounds left on the surface of the aqueous phase were completely removed and freshly added to chloroform. and

[Formula] at a ratio of 10 moles: 1 mole, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
Spread 0.5 ml on this aqueous phase and increase the surface pressure.
After adjusting to 30 dyne/cm, a monomolecular film consisting of three monolayers of the above two types of compounds was deposited on the previously formed first layer in the same manner as the formation of the first layer. A cumulative film was formed as the second layer. Next, the operation of forming a monomolecular film made of arachidic acid in Reference Example 3 was repeated four times to form a second insulating film made of four layers of cumulative monomolecular arachidic acid films as the third layer. After that, the above-described formation operation from the first layer to the third layer (four layers of arachidic acid monomolecular cumulative film) was repeated four times,
Light-emitting layer No. with four interfaces between the first layer and the second layer.
5 (layer thickness: approximately 1100 Å). Reference Example 5 [Formation of Light Emitting Layer No. 6] The same substrate as that used in Reference Example 1 was used in Reference Example 1.
The arachidic acid monolayer as the third layer was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 3, and the operation for forming a monomolecular film consisting of arachidic acid in Reference Example 3 was repeated twice. An insulating layer consisting of two stacked molecular films was formed on the electrode layer of the substrate. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and freshly added to chloroform. and at a ratio of 10mol:1mol, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
Spread 0.5 ml on this aqueous phase and increase the surface pressure.
After adjusting the temperature to 30 dyne/cm, the substrate on which the insulating layer made of arachidic acid was formed was gently immersed in the water phase again at a speed of 2 cm/min in the direction across the water surface of the water phase, and the above two types were added. A monomolecular film consisting of compound molecules was formed as a first layer on the insulating layer. Next, this substrate was pulled out of the water phase and again
It was left to dry at room temperature for more than a minute. Furthermore, the above compounds left on the surface of the aqueous phase were completely removed and freshly added to chloroform.

[Formula] and

[Formula] at a ratio of 10mol:1mol, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
Spread 0.5 ml on this aqueous phase and increase the surface pressure.
After adjusting to 30 dyne/cm, repeat the above first layer forming operation to form a second monomolecular film made of the above two types of compounds on the previously formed first layer.
Formed as a layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated 15 times, and finally the third layer is laminated to form a light emitting layer No. 1 having 15 interfaces between the first layer and the second layer. .
6 (layer thickness: about 1500 Å) was formed. Reference Example 6 [Formation of Light Emitting Layer No. 7] The same substrate as that used in Reference Example 1 was used in Reference Example 1.
It was immersed in the same aqueous phase for forming a monolayer as used in . Next, the operation for forming a monomolecular film made of arachidic acid in Reference Example 3 was repeated five times to form an insulating layer made of a five-layer cumulative film of monomolecular arachidic acid as the third layer. Here, the arachidic acid remaining on the surface of the aqueous phase is completely removed from the surface of the aqueous phase, and freshly added to chloroform.

[Formula] and

0.5 ml of a solution containing [Formula] dissolved in a ratio of 10 mol: 1 mol so that the total amount thereof has a concentration of 1 × 10 ^-3 mol / was spread on this aqueous phase, and the surface pressure was adjusted to 30 dyne. /cm, the substrate on which the monomolecular cumulative film insulating layer made of arachidic acid was formed was again gently immersed in the aqueous phase at a speed of 2 cm/min in the direction across the water surface of the aqueous phase, and then A first layer in which three monomolecular films made of the two types of compound molecules were stacked vertically was formed on the previously formed insulating layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Furthermore, apart from the aqueous phase used so far, [Eu
(BFA) ₄ ] Prepare an aqueous phase saturated with K, and add chloroform to the surface of this aqueous phase. and

[Formula] at a ratio of 10 moles: 1 mole, the total amount of these is 1×
of the solution dissolved to a concentration of 10 ^-3 mol/
After 0.5 ml was developed and the surface pressure was adjusted to 30 dyne/cm, a single molecule consisting of the above two types of compounds was placed on the previously formed first layer in the same manner as the formation of the first layer. A monomolecular cumulative film consisting of three film layers was formed as the second layer. Next, the operation of forming a monomolecular film made of arachidic acid in Reference Example 3 was repeated four times to form a second insulating film made of four layers of cumulative monomolecular arachidic acid films as the third layer. After that, the above-described formation operation from the first layer to the third layer (four layers of arachidic acid monomolecular cumulative film) was repeated four times,
Light-emitting layer No. with four interfaces between the first layer and the second layer.
7 (layer thickness: about 1100 Å) was formed. Reference Example 7 [Formation of Light Emitting Layer No. 8] A substrate similar to that used in Reference Example 1 was set at a predetermined position in a vapor deposition tank of a resistance heating vapor deposition apparatus, and methyl stearate was further placed in a resistance heating boat. (mp. 38°C), and after first reducing the pressure in the tank to a vacuum level of 10 ^-6 Torr, the current flowing through the boat was adjusted so that the deposition rate was 2 Å/sec, and a 200 Å methyl stearate layer was deposited. A vapor deposited layer consisting of the following was formed as a third layer on the transparent electrode layer of the substrate. The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was 20°C. Furthermore, this substrate was immersed in the same aqueous phase for forming a monomolecular film as that used in Reference Example 1. next,

[Formula] and

[Formula] at a ratio of 1mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform at a concentration of 10 ^-3 mol/was developed on the aqueous phase, and the surface pressure was adjusted.
After the multi-component monomolecular film consisting of the above two compounds was deposited on the surface of the aqueous phase, the substrate was gently moved up and down twice at a speed of 2 cm/min across the water surface. A monomolecular cumulative film as a first layer in which four monomolecular films made of a mixture of the above compounds were stacked was formed on the previously formed third layer. Now, pull this substrate out of the aqueous phase and
It was left to dry at room temperature for more than a minute. Furthermore, the above compounds left on the surface of the water phase are completely removed, the substrate is immersed in the water phase, and a new one is added. 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was developed on this aqueous phase, and the surface pressure was increased.
30 dyne/cm, a monomolecular film made of this compound was deposited on the aqueous phase, the substrate was gently pulled up at a speed of 2 cm/min in the direction across the water surface, and the above compound was further immersed and pulled up once. A second monomolecular film consisting of three layers of monomolecular films
The second layer was formed on the previously formed first layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated four times, and finally the third layer is laminated to form a light-emitting layer No. 1 having four interfaces between the first layer and the second layer. .
8 (layer thickness: approximately 1800 Å). Reference Example 8 [Formation of Light Emitting Layer No. 9] The same substrate as that used in Reference Example 1 was used in Reference Example 1.
It was immersed in the same aqueous phase for forming a monolayer as used in . Next, add stearic acid to the chloroform solution 1x
0.5 ml of the solution dissolved at a concentration of 10 ^-3 mol/was developed on the aqueous phase. After evaporating chloroform from the surface of the water phase, the surface pressure of the water phase was reduced to 30dyne/cm.
A film of stearic acid was precipitated on the surface of the aqueous phase. Furthermore, while keeping the surface pressure constant, the substrate was gently pulled up at a speed of 2 cm/min in the direction across the water surface to form a monomolecular film made of stearic acid molecules as a third layer on the electrode layer of the substrate. This was then pulled out of the aqueous phase and allowed to stand at room temperature for 30 minutes or more to dry. Furthermore, this operation was repeated twice to form a monomolecular cumulative film in which three monomolecular films made of stearic acid molecules were laminated as a third layer on the electrode layer of the substrate. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. Next, this substrate was set in a predetermined position in the deposition tank of the resistance heating evaporation equipment, and anthracene (mp. 216°C) was placed in the resistance heating boat, and the tank was first heated to a vacuum of 10 ^-6 Torr. After reducing the pressure to 200 Å, the current flowing through the boat was adjusted so that the deposition rate was 2 Å/sec, and a 200 Å deposited layer of anthracene was deposited as the first layer on the insulating layer as the third layer. Formed. The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was 20°C. After forming the first layer in this way, the electrode substrate is again immersed in the aqueous phase used previously to form the third layer, from which the remaining stearic acid has been completely removed, and then a new layer is added. 0.5 ml of a chloroform solution containing a concentration of 1 x 10 ^-3 mol/was developed on this aqueous phase, and the surface pressure was increased.
30 dyne/cm, and after forming a monomolecular film of the above compound on the aqueous phase, the substrate was gently pulled up at a speed of 2 cm/min in the direction across the water surface, and further dipping and pulling were performed once each to form a monomolecular film of the above compound on the water phase. A monomolecular cumulative film consisting of three monomolecular films was formed as a second layer on the previously formed first layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Thereafter, on the second layer formed in this way, the above-described operation for forming a monomolecular film made of stearic acid is repeated twice to form two monomolecular films made of stearic acid.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 9 (layer thickness: about 1500 Å) was formed. Reference Example 9 [Formation of Light Emitting Layer No. 10] The same substrate as that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as that used in Reference Example 1. Next, the operation for forming a monomolecular film made of stearic acid in Reference Example 8 was repeated three times to form a monomolecular film made of stearic acid molecules on the electrode layer of the substrate.
A monomolecular cumulative film stacked in layers was formed as the third layer. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. Next, the substrate on which the third layer was formed in this way is immersed again in the aqueous phase from which the remaining stearic acid has been completely removed, and then a new layer is added.

[Formula] and

[Formula] at a ratio of 1mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform to a concentration of 10 ^-3 mol/was developed on this aqueous phase,
After adjusting the surface pressure to 30 dyne/cm and forming a monomolecular film of the above compound on the aqueous phase, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface to form a film composed of molecules of the above compound. Monolayer is 4
The monomolecular stacked film was formed as a first layer on the previously formed third layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Next, this substrate was set at a predetermined position in the deposition tank of the resistance heating evaporation apparatus, and 2,5-diphenyloxazole was placed in the resistance heating boat, and the tank was first kept under a vacuum of 10 ^-6 Torr. After the pressure was reduced to 200 Å, the current flowing through the resistance heating boat was adjusted so that the deposition rate was 2 Å/sec. formed on a layer of The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was 20°C. Thereafter, on the second layer formed in this way, the above-described operation for forming a monomolecular film made of stearic acid is repeated twice to form two monomolecular films made of stearic acid.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 10 (layer thickness: approximately 2200 Å) was formed. Reference Example 10 [Formation of Light Emitting Layer No. 11] On the same substrate as that used in Reference Example 1, a vapor deposition layer consisting of a 200 Å methyl stearate layer similar to that formed in Reference Example 7 was formed. As the third layer,
It was formed in the same manner as in Reference Example 7. The substrate on which the third layer was formed was immersed in the same aqueous phase for forming a monomolecular film as that used in Reference Example 1. next,

[Formula] and

【formula】 as well as

[Formula] was dissolved in chloroform at a ratio of 50 mol: 50 mol: 1 mol, the total amount of which was 1 x 10 ^-3 mol/, and 0.5 ml of a solution was developed on the aqueous phase, and the surface pressure was adjusted to 30 dyne/cm. After the multicomponent monomolecular film consisting of the above two compounds was deposited on the surface of the aqueous phase, the substrate was moved 2 cm/2 cm in the direction across the water surface.
The first film, which had four layers of monomolecular film made of the mixture of the above compounds accumulated, was
A monomolecular cumulative film as a layer was formed on the previously formed third layer. Here, this substrate was taken out of the aqueous phase and left to dry at room temperature for 30 minutes or more. Furthermore, the above compounds left on the water phase surface are completely removed, the substrate is immersed in the water phase, and a new one is added.

[Formula] and

[Formula] at a ratio of 100mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform at a concentration of 10 ^-3 mol/cm was spread on this aqueous phase, the surface pressure was adjusted to 30 dyne/cm, and a monomolecular film consisting of the above compound was deposited on the aqueous phase. Then, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface, and a monomolecular cumulative film consisting of three monomolecular films made of the above compound molecules was first formed as the second layer. formed on the first layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated four times, and finally the third layer is laminated to form a light-emitting layer No. 1 having four interfaces between the first layer and the second layer. .
12 (layer thickness: approximately 1600 Å). Reference Example 11 [Formation of Light Emitting Layer No. 12] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, the operation for forming a monomolecular film made of stearic acid in Reference Example 8 was repeated three times to form a monomolecular stack in which three monomolecular films made of stearic acid molecules were laminated on the electrode layer of the substrate. A membrane was formed as the third layer. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. Next, this substrate was set at a predetermined position in the evaporation tank of the resistance heating evaporation apparatus, and anthracene (mp. 216°C) was placed in one of the resistance heating boats, and anthraquinone (mp. 286°C) was placed in the other one. ℃), and after first reducing the pressure inside the tank to a vacuum level of 10 ^-6 Torr,
The current flowing through the boat containing anthraquinone is kept constant so that the deposition rate of anthraquinone is approximately 0.1 Å/sec, and the deposition rate of the entire deposited layer consisting of a mixture of anthracene and anthraquinone is 2.
The current flowing through the boat containing anthracene was adjusted so that the current was
This layer was formed on the insulating layer as the third layer formed previously. The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was 20°C. After forming the first layer in this way, the substrate is immersed in the aqueous phase from which the remaining stearic acid has been completely removed, and then a new layer is added.

[Formula] and

[Formula] at a ratio of 100mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform at a concentration of 10 ^-3 mol/was spread on this aqueous phase, and the surface pressure was
30 dyne/cm, and after forming a monomolecular film of the above compound on the water phase, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface to form a monomolecular film of the above compound molecules. A monomolecular cumulative film consisting of four films was formed as a second layer on the previously formed first layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Thereafter, the above-described operation for forming a monomolecular film made of stearic acid was repeated four times on the second layer formed in this way, so that four monomolecular films made of stearic acid were formed.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 12 (layer thickness: approximately 1600 Å) was formed. Reference Example 12 [Formation of Light Emitting Layer No. 13] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, the operation of forming a monomolecular film made of stearic acid in Reference Example 8 was repeated four times to form a monomolecular stack in which four monomolecular films made of stearic acid molecules were laminated on the electrode layer of the substrate. A membrane was formed as the third layer. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. Next, the electrode substrate on which the third layer was formed in this way is immersed again in the aqueous phase from which the remaining stearic acid has been completely removed, and then the electrode substrate is re-immersed.

[Formula] and

[Formula] and

[Formula] was dissolved in chloroform at a ratio of 50 mol: 50 mol: 1 mol so that the total concentration was 1 x 10 ^-3 mol/, and 0.5 ml of the solution was developed on this aqueous phase, and the surface pressure was increased to 30 dyne. /cm, and after forming a monomolecular film of the above compound on the aqueous phase, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface to form a monomolecular film of the above compound molecules. A monomolecular cumulative film consisting of four layers was formed as a first layer on the previously formed third layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Next, this substrate was set in a predetermined position in the vapor deposition tank of the resistance heating vapor deposition apparatus, and carbazole (mp. 245°C) was placed in one of the resistance heating boats, and 2,5-difluoride was added to the other one. Add enyloxazole,
After first reducing the pressure inside the tank to a vacuum level of 10 ^-6 Torr,
The current flowing through the resistance heating boat containing carbazole was kept constant so that the vapor deposition rate of carbazole was about 0.4 Å/sec, and the
-2, so that the deposition rate of the entire deposited layer consisting of the mixture of diphenyloxazole is 2 Å/sec,
The current flowing through the boat containing 5-diphenyloxazole was adjusted, and 200 Å of carbazole and 2,
A vapor deposited layer of a mixture of 5-diphenyloxazole was formed as a second layer on the previously formed first layer. The degree of vacuum in the tank during deposition was maintained at 9 × 10 ^-6 Torr, and the temperature of the substrate holder was
The temperature was 20℃. Thereafter, on the second layer formed in this way, the above-described operation for forming a monomolecular film made of stearic acid is repeated twice to form two monomolecular films made of stearic acid.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 13 (layer thickness: approximately 1600 Å) was formed. Reference Example 13 [Formation of light-emitting layer No. 14] On the electrode layer of the same substrate as that used in Reference Example 1, a 200 Å layer similar to that formed in Reference Example 7 was formed.
A vapor deposited layer consisting of a methyl stearate layer was formed as the third layer in the same manner as in Reference Example 7, and the substrate on which this third layer was formed was used in the same manner as that used in Reference Example 1. It was immersed in a similar aqueous phase for monolayer formation. next,

[Formula] and

[Formula] and

[Formula] was dissolved in chloroform at a ratio of 50 mol: 50 mol: 1 mol, the total amount of which was 1 x 10 ^-3 mol/, and 0.5 ml of a solution was developed on the aqueous phase, and the surface pressure was adjusted to 30 dyne/cm. After the multi-component monomolecular film consisting of the above two compounds was deposited on the surface of the aqueous phase, the substrate was moved 2 cm/2 cm in the direction across the water surface.
The first film was made by gently moving it up and down twice at a speed of
A monomolecular cumulative film as a layer was formed on the previously formed third layer. Here, this substrate was taken out of the aqueous phase and left to dry at room temperature for 30 minutes or more. Furthermore, the above compounds left on the surface of the water phase are completely removed, the substrate is immersed in the water phase, and a new one is added.

[Formula] and

[Formula] at a ratio of 100mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform at a concentration of 10 ^-3 mol/cm was spread on this aqueous phase, the surface pressure was adjusted to 30 dyne/cm, and a monomolecular film consisting of the above compound was deposited on the aqueous phase. Then, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface, and a monomolecular cumulative film consisting of four monomolecular films made of the above compound molecules was first formed as the second layer. formed on the first layer. Thereafter, the above-described formation operation from the third layer to the second layer is repeated four times, and finally the third layer is laminated to form a light-emitting layer No. 1 having four interfaces between the first layer and the second layer. .
14 (layer thickness: approximately 1800 Å) was formed. Reference Example 14 [Formation of Light Emitting Layer No. 15] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, the operation for forming a monomolecular film made of stearic acid in Reference Example 8 was repeated three times to form a monomolecular stack in which three monomolecular films made of stearic acid molecules were laminated on the electrode layer of the substrate. A membrane was formed as the third layer. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. This substrate was set in a predetermined position in the evaporation tank of the resistance heating evaporation equipment, and anthracene (mp. 216°C) was placed in one of the resistance heating boats, and indazole (mp. 145°C) was placed in the other one. After first reducing the pressure in the tank to a vacuum level of 10 ^-6 Torr, the current flowing through the boat containing indazole was kept constant so that the indazole evaporation rate was about 0.2 Å/sec, and the anthracene and indazole were The current flowing through the boat containing anthracene was adjusted so that the entire vapor deposition rate of the mixture was 2 Å/sec, and a 200 Å vapor deposition layer consisting of a mixture of anthracene and indazole was first formed as the first layer. It was formed on the insulating layer as the third layer. In addition, the degree of vacuum in the tank during vapor deposition is 9×
Maintain the temperature of the substrate holder at ^10-6 Torr, 20
℃. After forming the first layer in this way, the electrode substrate is immersed in the aqueous phase from which the remaining stearic acid has been completely removed, and then a new layer is added.

[Formula] and

[Formula] at a ratio of 100mol:1mol, the total amount of these is 1×
0.5 ml of a solution dissolved in chloroform at a concentration of 10 ^-3 mol/was spread on this aqueous phase, and the surface pressure was
30 dyne/cm, and after forming a monomolecular film of the above compound on the water phase, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface to form a monomolecular film of the above compound molecules. A monomolecular cumulative film consisting of four films was formed as a second layer on the previously formed first layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Thereafter, on the second layer formed in this way, the above-described operation for forming a monomolecular film made of stearic acid is repeated twice to form two monomolecular films made of stearic acid.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 15 (layer thickness: approximately 1500 Å) was formed. Reference Example 15 [Formation of Light Emitting Layer No. 16] A substrate similar to that used in Reference Example 1 was immersed in the same aqueous phase for forming a monomolecular film as used in Reference Example 1. Next, the operation for forming a monomolecular film made of stearic acid in Reference Example 8 was repeated three times to form a monomolecular film made of stearic acid molecules on the electrode layer of the substrate.
A monomolecular cumulative film stacked in layers was formed as the third layer. Note that the stearic acid remaining on the surface of the water phase was completely removed from the surface of the water phase. Next, the electrode substrate on which the third layer was formed in this way is immersed again in the aqueous phase from which the remaining stearic acid has been completely removed, and then the electrode substrate is re-immersed.

[Formula] and

[Formula] and

[Formula] was dissolved in chloroform at a ratio of 50 mol: 50 mol: 1 mol so that the total concentration was 1 x 10 ^-3 mol/, and 0.5 ml of the solution was developed on this aqueous phase, and the surface pressure was increased. 30 dyne/cm, and after forming a monomolecular film of the above compound on the aqueous phase, the substrate was gently moved up and down twice at a speed of 2 cm/min in the direction across the water surface to form a monomolecular film of the above compound molecules. A monomolecular cumulative film consisting of four layers was formed as a first layer on the previously formed third layer. Next, this substrate was taken out of the aqueous phase and left to dry again at room temperature for 30 minutes or more. Next, this substrate was set in a predetermined position in the evaporation tank of the resistance heating evaporation equipment, and carbazole (mp. 245°C) was placed in one of the resistance heating boats, and anthraquinone (mp. 286°C) was placed in the other one. ℃), and after first reducing the pressure inside the tank to a vacuum level of 10 ^-6 Torr,
The current flowing through the boat containing anthraquinone is kept constant so that the deposition rate of anthraquinone is approximately 0.1 Å/sec, and the deposition rate of the entire deposited layer consisting of a mixture of carbazole and anthraquinone is 2.
The current flowing through the boat containing carbazole was adjusted so that the current was
The second layer was formed on the previously formed first layer.
In addition, the degree of vacuum in the tank during vapor deposition was set to 9×
Maintain the temperature of the substrate holder at 10 ^-6 Torr, 20
℃. Thereafter, on the second layer formed in this way, the above-described operation for forming a monomolecular film made of stearic acid is repeated twice to form two monomolecular films made of stearic acid.
A light-emitting layer having four interfaces between the first layer and the second layer is formed by forming a third layer in which the layers are stacked, and repeating the forming operation from the first layer to the third layer four times.
No. 16 (layer thickness: approximately 1500 Å) was formed. Reference Example 16 [Formation of light-emitting layer No. 17] An ITO layer with a thickness of 1500 Å was formed on a 50 mm square glass surface by sputtering method to form a substrate for forming a light-emitting layer having a transparent electrode layer, and further on the layer. A SiO ₂ film with a thickness of 1000 Å was laminated by sputtering to form an insulating layer as a third layer. This substrate was set in a predetermined position in the evaporation tank of the resistance heating evaporation equipment, and then triphenylamine (mp. 127°C) was placed in the resistance heating boat, and the tank was first brought to a vacuum level of 10 ^-6 Torr. After reducing the pressure, adjust the current flowing through the resistance heating boat so that the deposition rate is 2 Å/sec, and first form a 200 Å vapor deposition layer of triphenylamine on the transparent electrode layer of the substrate. was formed on the third layer. In addition, the degree of vacuum in the tank during vapor deposition was set to 9×
Maintain the temperature of the substrate holder at 10 ^-6 Torr, 20
℃. Next, instead of triphenylamine, anthracene (mp. 216°C) was used, and a 300 Å vapor-deposited layer of anthracene was formed as the second layer in the same manner as in the formation of the first layer. formed on the first layer. Furthermore, methyl stearate (mp. 38°C) was used instead of anthracene, and a 300 Å deposited layer of methyl stearate was formed as a new third layer in the same manner as in the formation of the first layer. It was formed on the second layer formed in . Thereafter, the above-described formation operation from the first layer made of triphenylamine to the third layer made of methyl stearate is repeated once again to obtain light emitting layer No. 1 having two interfaces between the first layer and the second layer. 17 (layer thickness; approx.
1800 Å) was formed. Reference Example 17 [Formation of Light Emitting Layer No. 18] A film with a thickness of 1000 Å was formed in the same manner as in Reference Example 1 on the electrode layer of the same substrate as that used in Reference Example 1.
A SiO ₂ film was laminated by sputtering to form an insulating layer as a third layer. After forming the third layer in this way, the electrode substrates were set in the vapor deposition tank, and the electrode substrates were further coated with one containing anthracene (mp. 216°C) and one containing anthraquinone (mp. 286°C). Two resistance heating boats are set in a deposition tank, and the inside of the tank is first heated.
After reducing the pressure to a vacuum level of 10 ^-6 Torr, the current of the resistance heating boat was set so that the deposition rate of anthraquinone was approximately 0.1 Å/sec, and the deposition rate of the entire deposited layer consisting of a mixture of anthracene and anthraquine was Adjust the current flowing through the resistance heating boat containing anthracenone so that it is 2 Å/sec,
A vapor deposited layer consisting of a mixture of anthracene and anthraquinone was formed on the insulating layer as the third layer, which was previously formed as the first layer. The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was 20°C. Furthermore, one of the resistance heating boats was replaced with one containing triphenylamine (mp. 245°C), and the other
The tank was replaced with one containing indazole (mp. 145°C), and the inside of the tank was first reduced to a vacuum level of 10 ^-6 Torr, and the indazole deposition rate was 0.1 Å/sec.
The current of the resistance heating boat was set so that the deposition rate of the entire deposited layer consisting of a mixture of triphenylamine and indazole was 2 Å/sec.
Adjust the current flowing through the boat containing triphenylamine so that was formed. The degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder in this case was also 20°C. Next, set the substrate in the vapor deposition tank, and then add methyl stearate (mp.38
After reducing the pressure in the tank to a vacuum level of 10 ^-6 Torr, the current flowing through the resistance heating boat was adjusted so that the deposition rate was 2 Å/sec, and a 200 Å methyl stearate layer was deposited. A third layer was formed over the previously formed second layer. In addition, the degree of vacuum in the tank during vapor deposition is 9×
The temperature was maintained at 10 ^-6 Torr, and the temperature of the substrate holder in this case was also 20°C. Thereafter, the above-described formation operation from the first layer to the third layer was repeated four times to form light-emitting layer No. 18 (layer thickness: approximately 2400 Å) having four interfaces between the first layer and the second layer. Formed. Reference Example 18 [Formation of Light Emitting Layer No. 19] A film with a thickness of 1000 Å was formed in the same manner as in Reference Example 1 on the electrode layer of the same substrate as that used in Reference Example 1.
A SiO ₂ film was laminated by sputtering to form an insulating layer as a third layer. After forming the third layer in this way, the electrode substrate is set in the vapor deposition tank of the resistance heating vapor deposition apparatus,
Furthermore, two resistance heating boats, one containing triphenylamine (mp. 127°C) and the other containing anthraquinone (mp. 286°C), were set in the vapor deposition tank, and the tank was first heated to 10 ^-6 Torr. After reducing the pressure to a vacuum level, the current flowing through the boat containing anthraquinone was kept constant so that the deposition rate of anthraquinone was approximately 0.1 Å/sec, and the deposition rate of the entire deposited layer consisting of a mixture of triphenylamine and anthraquinone was Adjust the current flowing through the boat containing triphenylamine so that it is 2 Å/sec,
A vapor deposited layer of 200 Å of a mixture of triphenylamine and anthraquinone was formed on the insulating layer as the third layer that had been previously formed as the first layer. In addition, the degree of vacuum in the tank during vapor deposition was set to 9×
Maintain the temperature of the substrate holder at 10 ^-6 Torr, 20
℃. Furthermore, one of the resistance heating boats was replaced with one containing anthracene (mp. 216°C), and the other one was also replaced with one containing indazole (mp. 145°C), and the inside of the tank was first heated to 10 ^-6 After reducing the pressure to a vacuum level of Torr, the current flowing through the resistance heating boat containing Idal was kept constant so that the indazole deposition rate was approximately 0.1 Å/sec, and the entire deposited layer consisting of a mixture of anthracene and indazole was deposited. The current flowing through the boat containing anthracene was adjusted so that the speed was 2 Å/sec, and a second vapor-deposited layer consisting of a mixture of anthracene and indazole with a thickness of 200 Å was applied.
This layer was formed on the insulating layer as the third layer formed previously. In this case as well, the degree of vacuum in the tank during vapor deposition was maintained at 9 x 10 ^-6 Torr, and the temperature of the substrate holder was also set at 20°C. Next, set the substrate in the vapor deposition tank, and then add methyl stearate (mp.38
After reducing the pressure in the tank to a vacuum level of 10 ^-6 Torr, the current flowing through the resistance heating boat was adjusted so that the deposition rate was 2 Å/sec, and a 200 Å methyl stearate layer was deposited. A third layer was formed over the previously formed second layer. In this case as well, the degree of vacuum in the tank during deposition was maintained at 9 × 10 ^-6 Torr, and the temperature of the substrate holder was also controlled.
The temperature was 20℃. Thereafter, the above-described formation operation from the first layer to the third layer was repeated four times to form light-emitting layer No. 19 (layer thickness: approximately 2400 Å) having four interfaces between the first layer and the second layer. Formed. Example An EL element of the present invention having the structure shown in FIG. 1 was formed as follows. Transparent electrode layer 1 was formed by depositing an ITO layer with a thickness of 1500 Å on a 50 mm square glass surface by sputtering method.
was formed. Next, any one of the light emitting layers (No. 17 to No. 19) formed in Reference Examples 16 to 18 on this transparent electrode layer 1
After forming one light-emitting layer 4, the substrate on which the light-emitting layer 4 was formed was set at a predetermined position in a vapor deposition tank of a vacuum evaporation apparatus, and the inside of the tank was heated once by 1x.
After reducing the pressure to a vacuum level of 10 ^-6 Torr, the vacuum level in the tank was adjusted to 9 x 10 ^-6 Torr, and the deposition rate was 5 Å/
An Au layer with a thickness of 50 Å was formed on the third layer located at the top of the light-emitting layer 4 to form the semi-transparent electrode layer 3. Furthermore, any one of the light emitting layers (No. 1 to No. 16) formed in Reference Examples 1 to 15 on the semitransparent electrode layer 3
After forming one as a light-emitting layer 5 having a monomolecular film or a monomolecular cumulative film, the substrate on which this light-emitting layer 5 has been formed is again set at a predetermined position in the evaporation tank of the vacuum evaporation apparatus. After reducing the pressure to a vacuum level of 1 × 10 ^-6 Torr, this time the vacuum level inside the tank was reduced to 1 × 10 -6 Torr.
Adjusted to ×10 ^-5 Torr, 1500 at a deposition rate of 20 Å/sec
An Al layer with a thickness of 1.5 Å is formed on the third layer located at the top of the light-emitting layer 5, and one selected from light-emitting layers No. 1 to No. 16 as the non-transparent back electrode layer 2 and the light-emitting One selected from layers No. 17 to No. 19 was combined as the light emitting layer 4 and the light emitting layer 5 to form a total of 48 EL elements of the present invention. As shown in FIG. 5, each of these EL elements of the present invention is sealed with a sealing glass 51, and then silicone oil 52 that has been purified, degassed, and dehydrated according to a conventional method is injected into the seal. ,EL
A cell 50 was formed. For each of these EL cells, an AC voltage (20 V, 400 Hz) was applied between electrode layers 1 and 3 and between electrode layers 2 and 3 to cause them to emit light, and the brightness and current density of the light emission were measured. However, 0.08～
Current density in the range of 0.13mA/ ^cm2 and 20-40ft-L
A range of brightness was measured.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an EL device of the present invention, FIG. 2 is a schematic cross-sectional view of an example of a light-emitting layer included in an EL device of the present invention, and FIG. A schematic diagram, FIG. 4 is a schematic diagram showing an example of the arrangement of molecules at the interface between the first layer and the second layer of the EL device of the present invention, and FIG. FIG. 2 is a schematic cross-sectional view of an EL cell. 1: Transparent electrode layer, 3: Transparent or translucent electrode layer, 2: Electrode layer, 4, 5: Luminescent layer, 21-1, 2
1-2: first layer, 22-1, 22-2: second layer, 23-1, 23-2, 23-3: third layer,
24-1, 24-2: Interface, 31, 31': Functional part, 32, 32': Hydrophilic part, 33, 3
3': hydrophobic part, 50: EL element, 51: glass seal, 52: silicone oil, 53: EL cell.

Claims (1)

[Claims] 1 Comprising two electrode layers, at least one of which is transparent, two light-emitting layers provided between these two electrode layers, and a transparent or translucent electrode layer provided between these two light-emitting layers. a three-terminal electroluminescent device, in which at least one of the light-emitting layers includes a first layer containing an organic compound relatively exhibiting electron-accepting property and an organic compound relatively exhibiting electron-donating property. a second layer and a third layer having electrically insulating properties, and these layers are arranged on the third layer from one side of the electrode layer to the other. and the third layer are 2 in this order.
The first layer, the second layer, and the third layer are laminated repeatedly at least one time, and at least one of the first layer, the second layer, and the third layer is composed of a monomolecular film or a monomolecular cumulative film. 3-terminal electroluminescent device.