Light-emitting element

Abstract

In light-emitting devices using fluorescence emission and phosphorescence emission, a multi-color light-emitting device that is advantageous for practical application. The objective is to provide this. [Solution] A first light-emitting layer comprising a host material and a fluorescent light-emitting substance, and two layers forming an excitation complex. A second light-emitting layer containing a type of organic compound and a material capable of converting triplet excitation energy into light emission. The present invention provides a light-emitting element having a stacked structure. The light emitted from the first light-emitting layer is then emitted from the second layer. Light-emitting elements whose emission spectrum peaks are located at shorter wavelengths than the emission from the layer are more useful. be.

Description

[Technical Field]

[0001] The present invention relates to a product, method, or method of manufacture. Or, the present invention relates to a process, machine Relating to a manufacturer or composition of matter. In one aspect of the present invention, a semiconductor device, a display device, a light-emitting device, a power storage device, and a method for driving them are provided. The present invention relates to, or to methods for producing them. In particular, one aspect of the present invention relates to using an organic compound as a luminescent substance. Light-emitting elements, display modules, lighting modules, display devices, and light-emitting devices used as such. , relating to electronic equipment and lighting devices. [Background technology]

[0002] In recent years, electroluminescence (EL) using organic compounds has been developed. Research and development of light-emitting elements (organic EL elements) that utilize nescence are actively underway. The basic structure of these light-emitting devices is an organic compound layer (E) containing a light-emitting material between a pair of electrodes. It has an L layer sandwiched in between. By applying a voltage to this element, light is emitted from the light-emitting material. You can obtain this.

[0003] Because these light-emitting elements are self-illuminating, they have high visibility and do not require a backlight. These advantages make it suitable as a flat panel display element. Furthermore, a major advantage of displays using such light-emitting elements is that they can be manufactured to be thin and lightweight. This is an advantage. Furthermore, its fast response time is another notable feature.

[0004] These light-emitting elements can emit light in a planar manner, making it easy to form large-area elements. This is possible. This applies to point light sources such as incandescent bulbs and LEDs, or fluorescent lamps. Since it is a characteristic that is difficult to obtain with a line light source represented by it, its utility value as a light source for lighting etc. is also high.

[0005] In the case of such an organic EL element, electrons are emitted from the cathode and holes are emitted from the anode respectively into the EL layer, and current flows. Then, the injected electrons and holes recombine so that the light-emitting organic compound is excited and light emission can be obtained.

[0006] As the excited state of the organic compound, there are a singlet excited state (S * ) and a triplet excited state (T * ), and the light emission from the singlet excited state is called fluorescence and the light emission from the triplet excited state is called phosphorescence . And the statistical generation ratio in the light-emitting element is S * :T * = 1:3 and is considered to be so.

[0007] In a compound that emits light from the singlet excited state (hereinafter referred to as a fluorescent substance), at room temperature , usually, light emission from the triplet excited state (phosphorescence) is not observed, and only light emission from the singlet excited state (fluorescence) is observed. Therefore, the theoretical limit of the internal quantum efficiency (the ratio of photons generated with respect to the injected carriers) in a light-emitting element using a fluorescent substance is S * :T * = 1:3 and is taken as 25%.

[0008] On the other hand, if a compound that emits light from the triplet excited state (hereinafter referred to as a phosphorescent compound) is used , light emission from the triplet excited state (phosphorescence) is observed. Also, since intersystem crossing easily occurs in the phosphorescent compound, the internal quantum efficiency can theoretically reach 100%. That is, phosphorescence Light-emitting devices using luminescent materials achieve higher luminescence efficiency than light-emitting devices using fluorescent materials. It becomes easier. For this reason, in order to realize a highly efficient light-emitting element, phosphorescent light-emitting material In recent years, there has been a great deal of activity in developing light-emitting elements using materials.

[0009] Patent Document 1 describes a light-emitting region having multiple light-emitting dopants, wherein the light-emitting dopants A white light-emitting element that emits phosphorescence is disclosed. In addition, Patent Document 2 describes a fluorescent light-emitting layer An element (a so-called tandem element) is disclosed which has an intermediate layer (charge generation layer) between it and a light-emitting layer. It is being done. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Special Publication No. 2004-522276 [Patent Document 2] Japanese Patent Publication No. 2006-024791 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] As a multicolor light-emitting element, such as a white light-emitting element, there is an intermediate layer between the fluorescent light-emitting layer and the phosphorescent light-emitting layer. Devices incorporating an interlayer (charge generation layer) have been developed and some have been put into practical use (see, for example, patent documents). (See 2). In a light-emitting element having this structure, light emission on the short wavelength side is obtained from the fluorescent emission layer, and long wavelength The light emission from the side is obtained from the phosphorescent layer.

[0012] This configuration uses fluorescence for the short-wavelength emission, which has a limited lifespan, and phosphorescence for the long-wavelength emission. By doing so, although the efficiency is lower than elements that obtain all light emission from phosphorescence, it is more stable. This configuration aims to obtain a multi-color light-emitting element with specific characteristics.

[0013] Multicolor light-emitting elements with this structure, which prioritizes reliability over performance, still have lifespan issues. While organic EL elements, which have many components, are advantageous for practical use, obtaining a single light-emitting element requires... It also has the disadvantage of requiring a large number of films to be layered, which is detrimental to practical application.

[0014] In a multicolor light-emitting element having the said configuration, an intermediate layer is provided between the phosphorescent layer and the fluorescent layer. There are several reasons for this, but one of them is to suppress the quenching of phosphorescence by the fluorescent emitting layer. It is.

[0015] The fluorescent emitting layer typically contains a condensed aromatic ring, such as anthracene, as the host material. In particular, substances having a condensed aromatic hydrocarbon ring skeleton are used, but these condensed aromatic ring skeletons Many materials that exhibit fluorescence tend to have relatively low triplet energy levels. Therefore, the fluorescence emission layer and phosphorescence... When the light-emitting layer is placed in contact with the fluorescent layer, the triplet excitation energy generated in the phosphorescent layer is transferred to the fluorescent layer. The exciton moves to the triplet level of the host material and becomes inactive. Triplet excitons have a long lifetime. Therefore, the diffusion distance of excitons is long, and the excitation energy generated at the interface between the fluorescent and phosphorescent layers Not only ghee, but also the excitation energy generated inside the phosphorescent layer away from the fluorescent layer is also firefly The light-emitting layer becomes deactivated by the host material, resulting in a significant decrease in luminescence efficiency. cormorant.

[0016] On the other hand, if a host material with a large triplet excitation energy is used in the fluorescence emission layer, such The problem is solved, but in that case the singlet excitation energy of the host material is very large. Therefore, energy transfer from the host material to the fluorescent dopant becomes insufficient, and fluorescence Sufficient luminescence efficiency cannot be obtained in the light-emitting layer. As a result, the non-radiative deactivation process of the host material This can also increase the size of the host material, which can degrade the characteristics of the element (especially its lifespan). A large singlet excitation energy of the material indicates that the HOMO-LUMO balance of the host material is large. This is equivalent to having a large gap, which can lead to an excessive increase in the drive voltage.

[0017] Therefore, in one aspect of the present invention, in a light-emitting element using fluorescence emission and phosphorescence emission, The objective is to provide a light-emitting element that is advantageous for chemical applications. Furthermore, using fluorescence emission and phosphorescence emission... In light-emitting devices, having a relatively small number of film-forming layers results in fewer manufacturing steps, which is advantageous for practical application. The objective is to provide a light-emitting element.

[0018] Alternatively, in another aspect of the present invention, in a light-emitting element using fluorescence emission and phosphorescence emission, The objective is to provide a light-emitting element with good luminescence efficiency.

[0019] Alternatively, in another aspect of the present invention, in a light-emitting element using fluorescence emission and phosphorescence emission, A light-emitting element that has a relatively small number of deposition layers, is advantageous for practical application, and has good luminous efficiency. The objective is to provide a novel light-emitting element. Alternatively, in another aspect of the present invention, a novel light-emitting element is provided. The task is to accomplish this.

[0020] Alternatively, in one aspect of the present invention, by using the above-mentioned light-emitting element, a device that can be manufactured inexpensively is available. Display modules, lighting modules, light-emitting devices, display devices, electronic devices, and lighting devices The purpose is to provide each of these.

[0021] Alternatively, in one aspect of the present invention, power consumption is reduced by using the above-mentioned light-emitting element. Display modules, lighting modules, light-emitting devices, display devices, electronic devices, and lighting The purpose is to provide each device individually.

[0022] The present invention only needs to solve one of the above-mentioned problems. [Means for solving the problem]

[0023] A first light-emitting layer 113a containing a host material and a fluorescent light-emitting substance, and two types that form an excitation complex. A second light-emitting layer 1 comprising a type of organic compound and a substance capable of converting triplet excitation energy into light emission. A light-emitting element having a stacked structure with 13b can achieve the above objective. The emission from the light-emitting layer 113a has a shorter wavelength spectrum than the emission from the second light-emitting layer 113b. Light-emitting elements that exhibit a peak in the hyphen are more useful.

[0024] One aspect of the present invention has a pair of electrodes and an EL layer sandwiched between the pair of electrodes, and the E The L layer has a first light-emitting layer 113a and a second light-emitting layer 113b, and the first light-emitting layer 113 The emission spectrum from a is shorter wavelength than the emission spectrum from the second emission layer 113b. Located in a long region, the first light-emitting layer 113a comprises at least a fluorescent light-emitting material and a host material. The second light-emitting layer 113b has the ability to convert at least triplet excitation energy into light emission. The material comprises a substance, a first organic compound, and a second organic compound, and the further first organic compound, The light-emitting element is characterized in that the second organic compound described above forms an excited complex.

[0025] Furthermore, one aspect of the present invention comprises a pair of electrodes and an EL layer sandwiched between the pair of electrodes, The EL layer is laminated with a first light-emitting layer 113a and a second light-emitting layer 113b in contact with each other, The emission spectrum from the first light-emitting layer 113a is the emission spectrum from the second light-emitting layer 113b. It exists in a wavelength region shorter than the luminescence, and the first light-emitting layer 113a is at least a fluorescent light-emitting material. The second light-emitting layer 113b has a host material and a triplet excitation energy The material comprises a substance that can convert light into light, a first organic compound, and a second organic compound, the first A light-emitting element characterized in that an organic compound and the second organic compound form an excitation complex. That is the case.

[0026] Alternatively, in another aspect of the present invention, in the above configuration, the triplet excitation from the excitation complex. A light-emitting element characterized by the transfer of energy to a substance that can convert energy into light. He is a child.

[0027] Alternatively, in another aspect of the present invention, in the above configuration, the singlet excitation level of the host material The triplet excitation level of the host material is greater than the singlet excitation level of the fluorescent material. This light-emitting device is characterized by being smaller than the triplet excitation level of the aforementioned fluorescent material.

[0028] Alternatively, in another aspect of the present invention, in the above configuration, the triplet excitation level of the host material However, this is smaller than the triplet excitation levels of the first organic compound and the second organic compound. This is a light-emitting element characterized by the following:

[0029] Alternatively, in another aspect of the present invention, in the above configuration, the host material is a condensed aromatic ring skeleton. This is a light-emitting element that is an organic compound having [a certain characteristic].

[0030] Alternatively, in another aspect of the present invention, the host material in the above configuration is an anthracene skeleton. This is a light-emitting element that is an organic compound having [a certain characteristic].

[0031] Alternatively, in another aspect of the present invention, in the above configuration, the host material is anthracene bone. It is an organic compound having a specific characteristic, and the earlier fluorescent material is an organic compound having a pyrene skeleton. It is a light-emitting element.

[0032] Alternatively, in another aspect of the present invention, in the above configuration, the second light-emitting layer 113b is the As materials that can convert triplet excitation energy into light emission, each has a different emission spectrum. This is a light-emitting element characterized by containing a species (where n is an integer greater than or equal to 2) of material.

[0033] Alternatively, in another aspect of the present invention, in the above configuration, the second light-emitting layer 113b is an n-layer A material consisting of n layers, each of which has a different triplet excitation energy that can be converted into light emission. This is a light-emitting element characterized by containing [a specific component].

[0034] Alternatively, in another aspect of the present invention, in the above configuration, the second light-emitting layer 113b is the As materials that can convert triplet excitation energy into light emission, each has a different emission spectrum. This light-emitting element is characterized by comprising a phosphorescent material (1) and a phosphorescent material (2). .

[0035] Alternatively, in another aspect of the present invention, in the above configuration, the first phosphorescent material is red The second phosphorescent material exhibits emission in the green region, and the fluorescent material The material is a light-emitting element that emits light in the blue region.

[0036] Alternatively, in another aspect of the present invention, in the above configuration, the first phosphorescent material is 58 The second phosphorescent material has emission spectrum peaks between 0 nm and 680 nm, and is 5 The emission spectrum has peaks between 00 nm and 560 nm, and the fluorescent material is 400 nm This is a light-emitting element that has an emission spectrum peak between m and 480 nm.

[0037] Alternatively, in another aspect of the present invention, in the above configuration, the second light-emitting layer 113b is the first It consists of a phosphorescent layer and a second phosphorescent layer, and the first phosphorescent layer contains the first phosphor The second phosphorescent layer contains a photoluminescent material, and the second phosphorescent material is included in the second phosphorescent layer. Its distinguishing feature is its light-emitting element.

[0038] Alternatively, in another aspect of the present invention, in the above configuration, the first light-emitting layer 113a and the previous The first phosphorescent layer and the second phosphorescent layer are stacked in this order, which is a characteristic feature of this invention. It is an optical element.

[0039] Alternatively, in another aspect of the present invention, in the above configuration, the first light-emitting layer 113a is an anode. The second phosphorescent layer is formed on the cathode side of the light-emitting element.

[0040] Alternatively, in another aspect of the present invention, in the above configuration, the first phosphorescent material is A light-emitting element characterized by exhibiting carrier trapping properties within the first phosphorescent layer. be.

[0041] Alternatively, in another aspect of the present invention, in the above configuration, the carrier trapping property is electronic This light-emitting element is characterized by its trapping properties.

[0042] Alternatively, one aspect of the present invention is a display module having a light-emitting element as described above. It is a rule.

[0043] Alternatively, one aspect of the present invention is a lighting module having a light-emitting element as described above. be.

[0044] Alternatively, one aspect of the present invention includes a light-emitting element as described above, and a control of the light-emitting element. It is a light-emitting device equipped with means for doing so.

[0045] Alternatively, one aspect of the present invention is a display unit having a light-emitting element as described above, and the light emission This is a display device equipped with means for controlling elements.

[0046] Alternatively, one aspect of the present invention has a light-emitting element as described above in the illumination unit, and the light emission This is a lighting device equipped with means for controlling the elements.

[0047] Alternatively, one aspect of the present invention is an electronic device having a light-emitting element as described above.

[0048] In this specification, the term "light-emitting device" includes image display devices that use light-emitting elements. Furthermore, the light-emitting element may have a connector, such as an anisotropic conductive film or TCP (Tape Carburetor). A module with a rier package attached, and a printed circuit board at the end of the TCP. A module or light-emitting element equipped with a COG (Chip On Glass) system Furthermore, all modules with directly mounted ICs (integrated circuits) are also included in the definition of light-emitting devices. Furthermore, this also includes light-emitting devices used in lighting fixtures and the like. [Effects of the Invention]

[0049] In one aspect of the present invention, in a light-emitting device using fluorescence emission and phosphorescence emission, the number of film layers is relative. This allows for the provision of a multi-color light-emitting element that is relatively low in complexity and advantageous for practical application.

[0050] Furthermore, in another aspect of the present invention, in a light-emitting element using fluorescence emission and phosphorescence emission, This makes it possible to provide a multi-color light-emitting element with good luminescence efficiency.

[0051] Furthermore, in another aspect of the present invention, a film formation in a light-emitting element using fluorescence emission and phosphorescence emission. A multicolor light-emitting element with a relatively small number of layers, which is advantageous for practical application, and which also has good luminescence efficiency. We can provide this.

[0052] Furthermore, another aspect of the present invention is that by using the above-mentioned light-emitting element, it is possible to manufacture inexpensively. Display modules, lighting modules, light-emitting devices, display devices, electronic equipment, and lighting equipment Each can be provided with their own placement.

[0053] Furthermore, in another aspect of the present invention, by using the above-mentioned light-emitting element, power consumption is reduced. Display modules, lighting modules, light-emitting devices, display devices, electronic devices, and lighting Each lighting device can be provided. [Brief explanation of the drawing]

[0054] [Figure 1] Conceptual diagram of a light-emitting element. [Figure 2] Conceptual diagram of an active matrix light-emitting device. [Figure 3] Conceptual diagram of an active matrix light-emitting device. [Figure 4] Conceptual diagram of an active matrix light-emitting device. [Figure 5] Conceptual diagram of a passive matrix type light-emitting device. [Figure 6] A diagram representing a lighting device. [Figure 7] A diagram representing electronic devices. [Figure 8] A diagram representing a light source device. [Figure 9] A diagram representing a lighting device. [Figure 10]A diagram representing a lighting device. [Figure 11] A diagram showing an in-vehicle display device and lighting system. [Figure 12] A diagram representing electronic devices. [Figure 13] A diagram showing the current density-luminance characteristics of the light-emitting element 1. [Figure 14] A diagram showing the brightness-current efficiency characteristics of the light-emitting element 1. [Figure 15] A diagram showing the voltage-luminance characteristics of light-emitting element 1. [Figure 16] A diagram showing the luminance-external quantum efficiency characteristics of light-emitting element 1. [Figure 17] Emission spectrum of light-emitting element 1. [Figure 18] A diagram showing the normalized brightness change of light-emitting element 1 over time. [Figure 19] Emission spectra of light-emitting element 2 and light-emitting element 3. [Figure 20] Emission spectrum of light-emitting element 4. [Figure 21] A correlation diagram of the energy levels of each substance and the excited complex in a light-emitting element according to one aspect of the present invention. [Modes for carrying out the invention]

[0055] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is as follows The description is not limited to the present invention, and the form and details may not depart from the spirit and scope of the present invention. Those skilled in the art will readily understand that the parameters can be modified in various ways. Accordingly, the present invention is described below. This should not be interpreted as being limited to the contents described in the embodiment.

[0056] (Embodiment 1) A schematic diagram of a light-emitting element according to one embodiment of the present invention is shown in Figure 1(A). This light-emitting element comprises at least EL layer 1 has a pair of electrodes (first electrode 101, second electrode 102) and an emissive layer 113. It has 03. Also, the light-emitting layer 113 consists of a first light-emitting layer 113a and a second light-emitting layer 113b. I have it.

[0057] In Figure 1(A), the EL layer 103 is further divided into a hole injection layer 111 and a hole transport layer 1 12. An electron transport layer 114 and an electron injection layer 115 are shown, but this layered structure is just one example. Therefore, the configuration of the EL layer 103 in one embodiment of the present invention is not limited thereto. Oh, in Figure 1(A), the first electrode 101 functions as the anode, and the second electrode 102 is It is illustrated as functioning as a cathode.

[0058] The first light-emitting layer 113a contains a fluorescent light-emitting substance and a host material. The photolayer 113b contains a first organic compound, a second organic compound, and a phosphorescent material. Furthermore, in the light-emitting layer having the said configuration, the first organic compound and the second organic compound are energized. This combination is used to form a complex.

[0059] With this configuration, the first light-emitting layer 113a emits light originating from the fluorescent material. However, light emission originating from the phosphorescent material can be efficiently obtained from both the second light-emitting layer 113b and the phosphorescent material. In this light-emitting element, a charge generation layer is located between the first light-emitting layer 113a and the second light-emitting layer 113b. Even without a tandem element, both fluorescence and phosphorescence emission are efficient. It can be obtained easily.

[0060] Normally, when a fluorescent emitting layer and a phosphorescent emitting layer are introduced into the same EL layer and made to emit light, phosphorescent emission occurs. The triplet excitation energy of the layer is transferred to the host material which makes up the majority of the fluorescence emission layer. This causes a significant decrease in luminescence efficiency. This is because the fluorescent luminescence layer typically uses a host material. Condensed aromatic rings (especially condensed aromatic hydrocarbon rings) such as anthracene, which have a low triplet energy level. Because a material with a skeletal structure is used, the triplet excitation energy generated in the phosphorescent layer This is because the fluorescence emissive molecules migrate to the host material of the fluorescence-emitting layer and become non-radiatively deactivated. Currently, fluorescence In the optical layer, without using a material with a condensed aromatic ring skeleton, the desired emission wavelength and good device characteristics can be achieved. • Because it is difficult to achieve reliability, the fluorescent emitting layer and the phosphorescent emitting layer are introduced into the same EL layer. With such a configuration, it is difficult to obtain a light-emitting element with good characteristics.

[0061] Furthermore, in the triplet excited state, the relaxation time is long, resulting in a long diffusion distance of excitons, and the fluorescence emission layer Many of the excitons generated inside the phosphorescent layer that have moved away from it also migrate to the fluorescence-emitting layer by diffusion. The fact that it moves and undergoes non-radiative deactivation is making the situation more serious.

[0062] In this embodiment, the second light-emitting layer 113b is made of the first organic compound and the second organic compound The compound forms an excited complex, and from this excited complex, triplet excitation energy is transferred to the phosphorescent material. The above problem can be solved by creating a configuration that allows light to be emitted while moving.

[0063] An excited complex is an excited state consisting of two substances. And the excited complex releases energy. When it returns to the ground state by releasing, the two substances that formed the excited complex also return to their original state. They behave as separate substances. In other words, the excited complex does not have a ground state. Furthermore, energy transfer between excited complexes, and energy transfer from other substances to excited complexes, are fundamental to the principle of It is unlikely to happen.

[0064] The formation of the excited complex in the light-emitting element is due to the first organic compound and the second organic compound, When one cation and the other anion are adjacent to each other, they directly form an excited complex. The electroplex process is considered to be dominant. Also, the first organic compound Even if one of the two organic compounds enters an excited state, it quickly incorporates the other substance. And because they form an excitation complex, most of the excitons in the second light-emitting layer 113b It exists as an excited complex.

[0065] Furthermore, the singlet excitation energy of the excited complex is the H of the first organic compound and the second organic compound. Of the OMO and LUMO levels, the difference between the higher HOMO level and the lower LUMO level is... Since this corresponds to the energy difference, it is greater than the singlet excitation energy of either of the two organic compounds. This value is also small, indicating singlet excitation from the excited complex to the first and second organic compounds. No energy transfer occurs. Furthermore, the triplet excitation energy of the excited complex is the first Preferably the first organic compound and the second organic compound are smaller than the organic compound or the second organic compound. Select the first and second organic compounds such that they are smaller than the second organic compound. By selecting, the energy from the excited complex to the first organic compound and the second organic compound is obtained. Movement can be made to almost zero. Also, as mentioned above, the energy between excited complexes Since there is almost no energy transfer, the diffusion of excitons within the second light-emitting layer 113b is almost complete. This does not occur, and as a result, the aforementioned problems can be solved.

[0066] Here, the first light-emitting layer 113a and the second light-emitting layer 113b, which are fluorescent light-emitting layers, are in contact and form If this is done, at the interface, the excited complex is transferred to the host material of the first light-emitting layer 113a. Energy transfer to (especially triplet energy transfer) can occur. However, as mentioned above... Since there is almost no diffusion of excitons in the second light-emitting layer 113b, from the excited complex The range in which energy transfer from the first light-emitting layer 113a to the host material occurs is extremely localized. It remains in the enclosure (i.e., the interface between the first light-emitting layer 113a and the second light-emitting layer 113b), and the excited energy This does not result in a large loss of energy. Therefore, the first light-emitting layer 113a and the second light-emitting layer 113b does not necessarily need to be in contact, but even if they are in contact, high efficiency can be achieved. This can be said to be a characteristic of one aspect of the present invention. That is, the first light-emitting layer 113a and the second An element structure formed in contact with the light-emitting layer 113b is also one aspect of the present invention.

[0067] Thus, the triplet excitation energy of the host material contained in the fluorescent layer is used for phosphorescence emission. The triplet excitation energies of the first and second organic compounds contained in the layer are smaller than the triplet excitation energies of the first and second organic compounds contained in the layer. Even in cases where fluorescence emission and phosphorescence emission are not present, by applying one aspect of the present invention, This makes it possible to obtain a light-emitting element that has good luminescence efficiency.

[0068] Furthermore, in a light-emitting element according to one aspect of the present invention, a first light-emitting layer 113a and a second light-emitting layer At the interface with 113b, energy is transferred from the excited complex to the host material of the first light-emitting layer 113a. Ghee transfer (especially triplet energy transfer) and the first light-emitting layer 113a from the phosphorescent material Even if energy transfer occurs to the host material, some of it is transferred to the first light-emitting layer 113a The configuration is such that it can be converted into light in three places. That is, the first light-emitting layer 113a is three Singlet excited states are generated by multiplet-triplet annihilation (TT annihilation; TTA). By creating a configuration that makes it easy to do so, the excyplex to H at the above interface A portion of the triplet excitation energy transferred to the light-emitting material is emitted as fluorescence in the first light-emitting layer 113a. It becomes possible to convert it into light. As a result, the light-emitting element in one aspect of the present invention This allows for the creation of light-emitting devices with reduced energy loss. Singlet excited state by TTA. In order to create a configuration that facilitates the generation of the first light-emitting layer 113a, the host material is single layer The number excitation level is greater than the singlet excitation level of the fluorescent material, and the host material is triplet excited. The host material and the fluorescent material are configured such that the starting level is lower than the triplet excitation level of the fluorescent material. The quality should be selected. For selecting a host material and fluorescent substance that have this kind of relationship, Typically, the host material is a material with an anthracene skeleton, and the fluorescent material is pyrene. A combination of materials having a skeletal structure is preferable.

[0069] Furthermore, if the first light-emitting layer 113a is too thick, light emission from the second light-emitting layer 113b will be reduced. It becomes difficult to obtain. Also, if the film thickness is too thin, it becomes difficult to obtain light emission from the first light-emitting layer 113a. Therefore, the film thickness of the first light-emitting layer 113a should be between 5 nm and 20 nm. It is preferable.

[0070] Furthermore, if the first light-emitting layer 113a is formed on the anode side, the first light-emitting layer 113a is It is preferable that the host material has hole transport properties. In this case, the host material should have bipods with high hole transport properties. It is preferable to use materials that have a lattice property. Such materials include an anthracene skeleton. Materials having the property of fluorescent material are preferred. Furthermore, if the hole-trapping properties of the fluorescent material are high (for example) The condensed aromatic amine compounds (as described later) should have a concentration of 5% or less, preferably 1% or more. Setting the concentration to 4% or less, and more preferably 1% to 3%, balances phosphorescence and fluorescence emission. This configuration is preferable for obtaining the material with good balance and high efficiency. Hole trapping occurs when O is higher than the HOMO of the host material.

[0071] In the second light-emitting layer 113b, the first organic compound and the second organic compound form an excitation complex. The combination of substances is only acceptable if it is possible to form an excited complex, but one of them It is more preferable that one material has hole-transporting properties and the other has electron-transporting properties. In this case, it becomes easier to form a donor-acceptor type excited state, and the excitation complex is efficiently formed. It becomes possible to form a body. In addition, materials that have hole transport properties and electron transport properties The combination of the first organic compound and the second organic compound is constructed by combining them with other materials. In this case, the carrier balance can be easily controlled by the mixing ratio. In terms of material properties, the ratio of hole-transporting materials to electron-transporting materials is 1:9 to 9:1 (by weight). A range including 1:9 and 9:1 is preferred. In particular, to further increase quantum efficiency, the In the region closest to the anode in the light-emitting layer 113b of 2, the material having hole transport properties: electron Transportable materials = 5:5 to 9:1 (weight ratio, including 5:5 and 9:1) It is more preferable to do so. Furthermore, a light-emitting element having such a configuration can easily perform carrier balancing. Because it can be controlled, the recombination region can also be easily controlled. Furthermore, A light-emitting element in one aspect of the present invention generates light by controlling the carrier balance as described above. It also has the feature of allowing adjustment of the light color.

[0072] In the light-emitting element of this embodiment, the carrier recombination region has a certain distribution. It is preferable that this is formed. To achieve this, each light-emitting layer must have appropriate carrier trapping properties. It is preferable that the phosphorescent material has electron-trapping properties, and in particular, it is preferable that the phosphorescent material has electron-trapping properties. Examples of materials with high electron-trapping properties include diazine bones such as pyrimidines and pyrazines. Examples include transition metal complexes containing ligands (such as iridium complexes and platinum complexes). Furthermore, the LUMO of the phosphorescent material is determined to be the same for both the first and second organic compounds. When the level is lower than that of the compound, the electron trapping property occurs.

[0073] In this light-emitting device, the light emitted from the first light-emitting layer 113a is emitted from the second light-emitting layer 11 It is preferable to have a configuration in which the emission peak is on the shorter wavelength side than the emission from 3b. Light-emitting elements using phosphorescent materials that exhibit long-lasting luminescence tend to degrade in brightness quickly. By converting short-wavelength emission to fluorescent emission, a light-emitting element with minimal brightness degradation can be provided. It is possible.

[0074] Furthermore, this light-emitting element has fewer layers for forming the EL layer compared to a tandem-type element. Furthermore, because the layer thickness is thin, it is cost-effective and suitable for mass production. Also, as mentioned above... Because the number of layers required to form the EL layer is small, the thickness of the EL layer can be made thin, and light It is also a scientifically advantageous configuration (a configuration with high light extraction efficiency). Furthermore, the drive voltage is also small, 5 To create a light-emitting element that efficiently obtains both fluorescence emission and phosphorescence emission at a driving voltage of V or less. It is possible.

[0075] Furthermore, even if the fluorescent emitting layer and the phosphorescent emitting layer are in contact, as described above, an excitation complex is used. Therefore, deactivation of the triplet excitation energy is less likely to occur, and both phosphorescence and fluorescence emission can be achieved. It is a configuration that is easy to achieve.

[0076] Energy level correlation diagram of each substance and exciplex in the light-emitting element described in this embodiment is shown in FIG. 21. In the figure, S FH is the singlet excitation level of the host material in the first light-emitting layer 113a, T FH is the triplet excitation level of the host material in the first light-emitting layer 113a, S FG , T FG are respectively the singlet excitation levels of the guest material (fluorescent substance) in the first light-emitting layer 113a PH , triplet excitation levels, S PH , T are respectively the singlet excitation levels, triplet excitation levels of the host material (the first E organic compound or the second organic compound) in the second light-emitting layer 113b, S E , T PG are the singlet excitation level and triplet excitation level of the exciplex in the second light-emitting layer 113b, T is the triplet excitation level of the guest material (phosphorescent substance) in the second light-emitting layer 113b

[0077] As shown in FIG. 21, in the first light-emitting layer 113a, TTA occurs due to the collision of triplet excited molecules of the host material , and a part of the triplet excited molecules of the host material is converted into singlet excited molecules (a part undergoes thermal deactivation). Then, the singlet excitation energy generated by this TTA moves to the singlet excited state of the fluorescent substance, and the energy is converted into fluorescence.

[0078] Also, in the second light-emitting layer 113b, the excitation levels S E , T E of the exciplex are smaller than the excitation levels S of the host material (the first PH , T PH organic compound and the second organic compound), so the excitation No excitation energy transfer occurs from the complex to the host material. Furthermore, the excited complex does not transfer excitation energy to other excitations. Naturally, there is no energy transfer to the excited complex. The excitation energy of the excited complex is transferred to the guest material (phosphorescence). When it moves to the luminescent material, it is converted into light. In this way, in the second luminescent layer 113b In this case, there is almost no diffusion of the triplet excitation energy, and it is converted into luminescence.

[0079] Thus, because there is almost no diffusion of triplet excitation energy, the first light-emitting layer 113a and the second Although there is some energy transfer at the interface to which the light-emitting layer 113b is in contact (for example, at the interface T of phosphorescent material present in PG From T FH Ya T FG Energy transfer to, etc., the first Light emission can be obtained with good efficiency from both the first light-emitting layer 113a and the second light-emitting layer 113b. Yes, it is possible. In the first light-emitting layer 113a, the triplet excitation energy by TTA is Because singlet excited states are generated by this, the energy transfer that occurs at the interface is also Because a portion of the energy can be converted into fluorescence, energy loss can be reduced. That is the case.

[0080] Furthermore, the light-emitting element in this embodiment comprises a first light-emitting layer 113a and a second light-emitting layer 113 By obtaining light of different emission wavelengths at point b, a multi-color light-emitting element can be created. The emission spectrum of a light-emitting element is a composite of light with different emission peaks, The resulting emission spectrum has at least two maxima.

[0081] Furthermore, such a light-emitting element is also suitable for obtaining white light emission. First light-emitting layer 113 By making the light from layer a and the second light-emitting layer 113b complementary in color, white light emission is obtained. It is possible to have multiple light-emitting elements with different emission wavelengths in either or both of the light-emitting layers. By using quality, it is possible to obtain highly color-rendering white light consisting of three or more colors. It is also possible to do this. In this case, each light-emitting layer is further divided into layers, and each divided layer It is also possible to include different luminescent materials.

[0082] Furthermore, in the second light-emitting layer 113b, the lowest energy absorption of the phosphorescent material occurs. By superimposing the emission spectrum of the band with that of the excited complex, a light-emitting element with better emission efficiency can be obtained. This can be done. Furthermore, the peak wavelength of the lowest energy absorption band of the phosphorescent material and the excitation If the difference in the energy equivalent of the peak wavelengths of the emission spectra of the resulting complex is 0.2 eV or less, The large overlap is a desirable configuration. Furthermore, the lowest energy absorption of the phosphorescent material is also present. The band is preferably the absorption band of the triplet excitation level, and as described later, it can be replaced with phosphorescent material. When using TADF material, the lowest energy absorption band is the absorption band of the singlet excitation level. It is preferable that this be the case.

[0083] In Figure 1(A), the first light-emitting layer 113a functions as the first electrode 101 On the side where the second light-emitting layer 113b is formed, the second electrode 102 side which functions as a cathode is formed. The stacking order can be reversed. That is, the first light-emitting layer 113a can be the cathode. The second electrode 102 is formed on the side where it functions, and the second light-emitting layer 113b functions as the anode. It may also be formed on the electrode 101 side of 1.

[0084] In this embodiment, the luminescent material contained in the second light-emitting layer 113b is triple-excited. Any material that can convert electromotive energy into light emission will suffice, and in the above explanation, phosphorescent material Regarding the part described as quality, it is thermally activated delayed fluorescence. Ted delayed fluorescence (TADF) material and phosphorescent layer The part written as can be interpreted as TADF luminescent layer. TADF material is The triplet excited state is upconverted to a singlet excited state by a small amount of thermal energy. It is easy to perform reverse intersystem crossing, and it efficiently exhibits luminescence (fluorescence) from the singlet excited state. It refers to a substance. Conditions for efficiently obtaining thermally activated delayed fluorescence include the triplet excitation level. The energy difference between the singlet excitation level and the singlet excitation level is 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0 One characteristic is that the voltage is less than 0.1 eV. Both phosphorescent materials and TADF materials are triplet materials. It is a substance capable of converting excitation energy into light emission.

[0085] (Embodiment 2) In this embodiment, an example of the detailed structure of the light-emitting element described in Embodiment 1 is shown in Figure 1(A The following explanation uses the following method.

[0086] The light-emitting element in this embodiment has an EL layer consisting of multiple layers between a pair of electrodes. In this embodiment, the light-emitting element includes a first electrode 101, a second electrode 102, and a first It consists of an EL layer 103 provided between electrode 101 and second electrode 102. In this embodiment, the first electrode 101 functions as the anode, and the second electrode 102 functions as the cathode. The following explanation assumes that it functions as follows: In other words, the first electrode 101 is more like the second electrode 10 A voltage was applied to the first electrode 101 and the second electrode 102 so that the potential was higher than 2. Sometimes, the device is configured to emit light.

[0087] Since the first electrode 101 functions as an anode, it has a large work function (specifically 4.0e Formed using metals, alloys, conductive compounds, and mixtures thereof (V or higher). Preferred. Specifically, for example, indium tin oxide (ITO) indium oxide-tin oxide containing silicon or silicon oxide, Indium oxide containing zinc oxide, tungsten oxide, and zinc oxide ( Examples include IWZO. These conductive metal oxide films are usually produced by sputtering. Although it is formed by film deposition, it may also be fabricated using methods such as the sol-gel method. Indium oxide-zinc oxide is composed of 1 to 20 wt% zinc oxide relative to indium oxide. One method involves forming the material using a sputtering technique with an added target. Indium oxide (IWZO) containing tungsten and zinc oxide is indium oxide In contrast, a tungsten oxide containing 0.5 to 5 wt% and zinc oxide containing 0.1 to 1 wt% It can also be formed by sputtering using a GET. In addition, gold (Au), Platinum (Pt), Nickel (Ni), Tungsten (W), Chromium (Cr), Molybdenum ( Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or metals. Examples of materials include nitrides (e.g., titanium nitride). Graphene can also be used. Furthermore, the composite material described later is used in the layer that comes into contact with the first electrode 101 in the EL layer 103. This allows for the selection of electrode materials regardless of the work function.

[0088] The laminated structure of the EL layer 103 is such that the light-emitting layer 113 has the configuration shown in Embodiment 1. If that is the case, then other elements are not particularly limited. For example, hole injection layer, hole transport layer, light-emitting layer, electron The structure is constructed by appropriately combining a transport layer, electron injection layer, carrier block layer, intermediate layer, etc. Yes, it is possible. In this embodiment, the EL layer 103 is a hole layer that is sequentially stacked on top of the first electrode 101. Injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115 The following describes the configuration having the following characteristics. The materials that make up each layer are specifically shown below.

[0089] The hole injection layer 111 is a layer containing a material with high hole injection potential. This includes molybdenum oxide and vanadium. Uses materials such as zinc oxide, ruthenium oxide, tungsten oxide, and manganese oxide. This can be done. In addition, phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (CuPC) can be used. Phthalocyanine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl )-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis (3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl Aromatic amine compounds such as phenyl-4,4'-diamine (abbreviation: DNTPD), or por Li(3,4-ethylenedioxythiophene) / Poly(styrenesulfonic acid)(PEDOT The hole injection layer 111 can also be formed using polymers such as PSS.

[0090] Furthermore, the hole injection layer 111 contains a hole transporting substance and an acceptor substance. Composite materials can be used. Furthermore, the hole-transporting material may contain an acceptor material. By using this method, it is possible to select the material for forming the electrodes regardless of the work function of the electrodes. Yes, it is possible. In other words, not only materials with a large work function can be used as the first electrode 101, but also materials with a large work function. Smaller materials can also be used. Acceptable materials include 7, 7, 8 ,8-Tetracyano-2,3,5,6-Tetrafluoroquinodimethane (abbreviation: F4-TC Examples include NQ, chloranil, etc. Transition metal oxides can also be mentioned. Furthermore, oxides of metals belonging to groups 4 through 8 of the periodic table can be listed. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide. Den, tungsten oxide, manganese oxide, and rhenium oxide are preferred due to their high electron-accepting properties. In particular, molybdenum oxide is stable in the atmosphere, has low hygroscopicity, and is easy to handle. preferable.

[0091] Examples of hole-transporting substances used in composite materials include aromatic amine compounds and carbazole derivatives. Body, aromatic hydrocarbons, polymer compounds (oligomers, dendrimers, polymers, etc.), species Various organic compounds can be used. Note that the organic compounds used in the composite material are... It is preferable that the organic compound has high pore transport properties. Specifically, 10 -6 cm 2 / Vs or later It is preferable that the material has the above hole mobility. Below, hole transport in composite materials The following is a list of specific organic compounds that can be used as transportable substances.

[0092] For example, aromatic amine compounds include N,N'-di(p-tolyl)-N,N'-diph Phenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4- [Diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N ,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diph Phenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3 ,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene Examples include (abbreviated as DPA3B).

[0093] Carbazole derivatives that can be used in composite materials include, specifically, 3-[N- (9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarb Zol (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3 -yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2) , 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino] Examples include -9-phenylcarbazole (abbreviated as PCzPCN1).

[0094] In addition, other carbazole derivatives that can be used in composite materials include 4,4'- di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N- Carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl- 9-Anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[ Using 4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. It is possible to be there.

[0095] Furthermore, examples of aromatic hydrocarbons that can be used in composite materials include 2-tert -butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-Diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-Bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene Cene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn) th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthrace n, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl Chil-9,10-di(2-naphthyl)anthracene, 9,9'-biantril, 10,1 0'-Diphenyl-9,9'-biantryl, 10,10'-bis(2-phenylphenyl Ru)-9,9'-Biantrill, 10,10'-Bis[(2,3,4,5,6-Pentaf [phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, Examples include perylene and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 Using aromatic hydrocarbons with hole mobility of / Vs or higher and having 14 to 42 carbon atoms. It is preferable to do so.

[0096] Furthermore, aromatic hydrocarbons that can be used in composite materials may have a vinyl skeleton. i. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2- Diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2- Examples include diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA).

[0097] Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphen Nylamine (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl [amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( Abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis High molecular weight compounds such as (phenyl)benzidine (abbreviated as Poly-TPD) can also be used. can.

[0098] By forming a hole injection layer, hole injection performance is improved, and a low driving voltage is required. This makes it possible to obtain optical elements.

[0099] The hole transport layer 112 is a layer containing a hole-transporting substance. The hole-transporting substance is: For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated) Name: NPB) or N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1, 1'-Biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-Tris (N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4 Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (Abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene-2) -yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'- (9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), etc. Aromatic amine compounds and the like can be used. The substances described herein have high hole transport properties. , mainly 10 -6 cm 2 It is a material having a hole mobility of / Vs or greater. Also, the above-mentioned composite material The organic compounds listed as hole-transporting substances in the material can also be used in the hole transport layer 112. Yes, it is possible. Also, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyl carbazole) High molecular weight compounds such as riphenylamine (PVTPA) can also be used. The layer containing the hole-transporting material is not limited to a single layer, but may consist of two or more layers made of the above material. It may also be made into a stacked structure.

[0100] In a light-emitting element according to one aspect of the present invention, when the first light-emitting layer 113a is provided on the anode side, The HOMO level of the material used in the hole transport layer 112 and the HOMO level in the first light-emitting layer 113a It is preferable that the HOMO levels of the material are in close proximity (energy difference of 0.2 eV or less). This prevents the holes from being trapped too much in the trap level, thus preventing the first light-emitting layer from being over-trapped. Because it flows to 113a and the second light-emitting layer 113b, it balances fluorescence emission and phosphorescence emission. Often, it becomes easier to obtain it with good efficiency.

[0101] The light-emitting layer 113 has the configuration of the light-emitting layer 113 described in Embodiment 1. That is, The device is constructed by stacking a first light-emitting layer 113a and a second light-emitting layer 113b from the electrode side of 1. It is present. In addition, the first light-emitting layer 113a contains a host material and a fluorescent light-emitting substance, and the second The light-emitting layer 113b contains a first organic compound, a second organic compound, and triplet excitation energy This includes a substance (phosphorescent compound or TADF material) that can convert light into light. In the form of a light-emitting element, the first organic compound and the second organic compound form an excited complex. It is assumed to be a combination. Furthermore, the excited complex is capable of converting the triplet excitation energy into luminescence. It provides energy to the material, and both the first light-emitting layer 113a and the second light-emitting layer 113b emit light together This method allows for efficient emission of light.

[0102] In the first light-emitting layer 113a, the materials that can be used as fluorescent light-emitting materials are as follows: Examples include the following. In addition, various other fluorescent materials can be used. It is possible to be there.

[0103] 5,6-Bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyri Zin (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-antri [Lu)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N, N'-Bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N' -Diphenyl-pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'- Bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorene] -9-yl)phenyl]-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAP) rn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N' -Diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-Cal Bazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (Abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-di Phenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-di Phenyl-N-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazo 3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-ter t-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4' -(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCB) APA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4) ,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine ] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl- 2-Anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA) ), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N' -Triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N' ,N',N'',N'',N''',N'''-Octaphenyldibenzo[g,p]cri Sen-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9 ,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3 -amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2- [Iyl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviated) Name: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N’, N’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9, 10-bis(1,1’-biphenyl-2-yl)-2-anthryl]-N,N’,N’- triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis (1,1’-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl) phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 5 45T, N,N’-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12 -bis(1,1’-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl -4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2- methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quin olizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation : DCM2), N,N,N’,N’-tetrakis(4-methylphenyl)tetracene- 5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N’, N’-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3 ,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-( 1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile Trill (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7, 7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoli din-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation : DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl} -4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2- {2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7 -tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H -pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), etc. can be mentioned. In particular, condensed aromatic diamine compounds typified by pyrenediamine compounds such as 1,6FLPAPrn and 1,6mMemFLPAPrn have high hole trap properties and are preferable because of their excellent luminescence efficiency and reliability. In the first light-emitting layer 113a, substances that can be used as host materials include, for example, the following. 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9

[0104] -anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo For example, the following can be mentioned.

[0105] 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9 -anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo -anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo -anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo -anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo b)Naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{ 4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthra Examples include anthracene compounds such as sen (abbreviated as FLPPA). By using such a material as a host material, it is possible to realize a light-emitting layer with good luminescence efficiency and durability. This is possible. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are It exhibits very good characteristics, making it a preferable choice.

[0106] In the second light-emitting layer 113b, a substance that can convert triplet excitation energy into light emission. In terms of quality, phosphorescent materials and TADF materials fall into this category, and examples include the following: It is possible.

[0107] Examples of phosphorescent substances include tris{2-[5-(2-methylphenyl)-4-(2,6- Dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl- κC} Iridium(III) (abbreviation: Ir(mpptz-dmp)3), Tris(5-methyl) (Tyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) Abbreviation: Ir(Mptz)3), Tris[4-(3-biphenyl)-5-isopropyl-3] -phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(i) Organometallic iridium complexes with a 4H-triazole skeleton, such as Prptz-3b)3) The body, or Tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2 ,4-Triazolat] Iridium(III) (abbreviation: Ir(Mptz1-mp)3), RIS(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) 1H-triazoles such as Rydium(III) (abbreviation: Ir(Prptz1-Me)3) iridium organometallic complexes having a rib skeleton, fac-tris[(1-2,6-diisopropyl Iridium(III) (abbreviation: Ir) (iPrpmi)3), Tris[3-(2,6-dimethylphenyl)-7-methylimida Zo[1,2-f]phenantridinato]iridium(III) (abbreviation: Ir(dmpim) Organometallic iridium complexes having an imidazole skeleton such as pt-Me)3), bis[2 -(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium (III) Tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'- Difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviated) Name: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl] Pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Ir(CF3pp) y)2(pic)), bis[2-(4',6'-difluorophenyl)pyridinate-N, C 2’ ] Iridium(III) acetylacetonate (abbreviation: FIracac) Examples include organometallic iridium complexes using phenylpyridine derivatives with electron-withdrawing groups as ligands. These compounds exhibit blue phosphorescence, from 440 nm to 520 nm. It is a compound that exhibits a luminescence peak.

[0108] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), Tris(4-t-butyl-6-phenylpyrimidinato)iridium Iridium(III) (abbreviation: Ir(tBuppm)3), bis(6-methyl-4-phenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(mppm)2(acac)), bis(6-tert-butyl-4-phenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(tBuppm)2(acac)), bis[6-(2-norbornyl)-4-phenylpyrimidinato](acetylacetonato)iridium(III) (abbreviation: Ir(nbppm)2(acac)), bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato](acetylacetonato)iridium(III) (abbreviation: Ir(mpmppm)2(acac)), bis(4,6-diphenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(dppm)2(acac)), and other organometallic iridium complexes having a pyrimidine skeleton, or bis(3,5-dimethyl-2-phenylpyrazinato)(acetylacetonato)iridium(II) (abbreviation: Ir(mppr-Me)2(acac)), bis(5-isopropyl-3-methyl-2-phenylpyrazinato)(acetylacetonato)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)), and other organometallic iridium complexes having a pyrazine skeleton, tris(2-phenylpyridinato-N,C)iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N,C)iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)) bis(6-methyl-4-phenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(mppm)2(acac)), bis(6-tert-butyl-4-phenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(tBuppm)2(acac)), bis[6-(2-norbornyl)-4-phenylpyrimidinato](acetylacetonato)iridium(III) (abbreviation: Ir(nbppm)2(acac)), bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato](acetylacetonato)iridium(III) (abbreviation: Ir(mpmppm)2(acac)), bis(4,6-diphenylpyrimidinato)(acetylacetonato)iridium(III) (abbreviation: Ir(dppm)2(acac)), and other organometallic iridium complexes having a pyrimidine skeleton, or bis(3,5-dimethyl-2-phenylpyrazinato)(acetylacetonato)iridium(II) (abbreviation: Ir(mppr-Me)2(acac)), bis(5-isopropyl-3-methyl-2-phenylpyrazinato)(acetylacetonato)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)), and other organometallic iridium complexes having a pyrazine skeleton, tris(2-phenylpyridinato-N,C)iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N,C)iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)) bis(3,5-dimethyl-2-phenylpyrazinato)(acetylacetonato)iridium(II) (abbreviation: Ir(mppr-Me)2(acac)), bis(5-isopropyl-3-methyl-2-phenylpyrazinato)(acetylacetonato)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)), and other organometallic iridium complexes having a pyrazine skeleton, tris(2-phenylpyridinato-N,C)iridium(III) (abbreviation: Ir(ppy)3), 2’ bis(2-phenylpyridinato-N,C)iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)) 2’ bis(2-phenylpyridinato-N,C)iridium(III) acetylacetonate (abbreviation: Ir(ppy)2(acac)), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)) bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bzq)2(acac)) 2(acac), Tris(benzo[h]quinolinato) iridium(III) (abbreviation: I r(bzq)3), Tris(2-phenylquinolinato-N,C) 2’ Iridium (III )(Abbreviation: Ir(pq)3), bis(2-phenylquinolinato-N,C) 2’ )iridium (III) Pyridogenes such as acetylacetonate (abbreviation: Ir(pq)2(acac)) In addition to organometallic iridium complexes with a rib skeleton, tris(acetylacetonate)(monofe) Nanthroline terbium(III) (abbreviation: Tb(acac)3(Phen)) Rare earth metal complexes can also be used. These are mainly compounds that exhibit green phosphorescence. It has an emission peak between 500 nm and 600 nm. Furthermore, it possesses a pyrimidine skeleton. Organometallic iridium complexes are particularly preferred because they exhibit outstanding reliability and luminescence efficiency. .

[0109] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrim [Dinato] Iridium(III) (abbreviation: Ir(5mdppm)2(dibm)), Bis[ 4,6-Bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium Mu (III) (abbreviation: Ir(5mdppm)2(dpm)), Bis[4,6-ji(naphtha) [Len-1-yl)pyrimidinato](dipivaloylmethanato) Iridium(III) (abbreviation) :Organometallic iridium having a pyrimidine skeleton such as Ir(d1npm)2(dpm) Mu complexes, such as (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridi Um(III) (abbreviation: Ir(tppr)2(acac)), bis(2,3,5-trif) Iridium(III) (Abbreviation: Ir(tp) pr)2(dpm)),(acetylacetonate)bis[2,3-bis(4-fluorophosphate) Iridium (III) (abbreviation: Ir(Fdpq)2(acac)) ) an organometallic iridium complex having a pyrazine skeleton, such as tris(1-phenylisopropyl alcohol). Norinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(piq)3), bis(1- Phenylisoquinolinate-N,C 2’ Iridium(III) (abbreviation: Ir(piq)2) In addition to organometallic iridium complexes with a pyridine skeleton such as (acac), 2,3,7 ,8,12,13,17,18-Octaethyl-21H,23H-Porphyrin Platinum (I Platinum complexes such as I) (abbreviation: PtOEP), and tris(1,3-diphenyl-1,3- Propanedionato (monophenanthroline) europium(III) (abbreviation: Eu(D) BM)3(Phen)), Tris[1-(2-Tenoyl)-3,3,3-Trifluoro Setonato (monophenanthroline) europium(III) (abbreviation: Eu(TTA)3) Rare earth metal complexes such as (Phen) can also be used. These produce red phosphorescence. It is a luminescent compound with an emission peak between 600 nm and 700 nm. Organometallic iridium complexes with a radin skeleton produce a highly chromatic red emission.

[0110] Furthermore, in addition to the phosphorescent compounds mentioned above, various phosphorescent light-emitting materials can also be selected and used. good.

[0111] The following materials can be used as TADF materials.

[0112] Fullerenes and their derivatives, acridine derivatives such as proflavin, eosin, etc. Also, Magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt) Metal-containing porphyrins, including indium (In) or palladium (Pd), etc. Examples of metal-containing porphyrins include protoporphyrins shown in the following structural formula - Tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(H emato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (S nF2(Copro III-4Me), Octaethylporphyrin-Tin Fluoride Complex (SnF2(OEP)), Ethioporphyrin-tin fluoride complex (SnF2(Etio I)) Other examples include octaethylporphyrin-platinum chloride complex (PtCl2OEP). .

[0113] [ka]

[0114] Furthermore, the following structural formula shows 2-(biphenyl-4-yl)-4,6-bis(12-) Enylindoro[2,3-a]carbazole-11-yl)-1,3,5-triazine( Complexes having π-electron-rich and π-electron-deficient heteroaromatic rings such as PIC-TRZ Ring compounds can also be used. These heterocyclic compounds include a π-electron-rich heteroaromatic ring and π electrons. Because it has a deficient heteroaromatic ring, it has high electron transport and hole transport properties, which is desirable. A substance in which an electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is a π-electron-rich heteroaromatic ring. Both the donor properties of the heteroaromatic ring and the acceptor properties of the π-electron-deficient heteroaromatic ring become stronger, S1 This is particularly preferable because it reduces the energy difference between the level and the T1 level.

[0115] [ka]

[0116] Materials that can be used as the first organic compound and the second organic compound mentioned above include: There are no particular limitations as long as the combination satisfies the conditions described in Form of Implementation 1, and various types of k You can select the carrier transport materials.

[0117] For example, an electron-transporting material is bis(10-hydroxybenzo[h]quinoli Sodium beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolate) )(4-phenylphenolate)aluminum(III) (abbreviation: BAlq), bis(8- Zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl) [Phenolate]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl) Metal complexes such as phenolate zinc(II) (abbreviation: ZnBTZ) and 2-(4-biphenyl Ryl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation) :PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butyl) Enyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-te rt-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl) Phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5 -Benzenetriyl)tris(1-phenyl-1H-benzoimidazole) (abbreviation: TP) BI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H -Polyazole skeletons such as benzimidazole (abbreviation: mDBTBIm-II) Heterocyclic compounds, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f, [h]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothioff) [f,h]quinoxaline (abbreviation: 2m) DBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl -3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6- Bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP) 2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: Heterocyclic compounds having a diazine skeleton, such as 4,6mDBTP2Pm-II, and 3,5-bi Su[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPP) y), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyP) Examples include heterocyclic compounds having a pyridine skeleton, such as B). Among those mentioned above, diazine Heterocyclic compounds with a skeleton or heterocyclic compounds with a pyridine skeleton are highly reliable. Preferred. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton are electron It offers high transportability and contributes to reducing drive voltage.

[0118] Furthermore, as a material that possesses hole transport properties, 4,4'-bis[N-(1-naphthyl)-N- Phenylaminobiphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl) -N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TP) D) 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-fe [Nylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfull Oren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'- (9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenyl Min (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9- H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-( 1-Naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)-triphenyl Luamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-fe Nyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9 ,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3- [Iylphenyl]-fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [4-(9-phenyl-9H-carbazole-3-yl)phenyl]-spiro-9,9' Compounds having an aromatic amine skeleton such as -bifluorene-2-amine (abbreviated as PCBASF) Compounds, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di( N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenyl) Phenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl Compounds having a carbazole skeleton, such as ru-9H-carbazole (abbreviation: PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)( Abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-f Luoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldi Compounds containing a thiophene skeleton, such as benzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation) :DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl) Phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) and other furans Compounds having an aromatic amine skeleton are examples. Among those mentioned above, compounds having an aromatic amine skeleton are examples. Compounds with a carbazole skeleton are reliable and have high hole transport properties. This is preferable because it also contributes to reducing the drive voltage.

[0119] In addition to the carrier transport materials mentioned above, various other materials can be used as carrier transport materials. It is also acceptable to use three phosphorescent compounds as the first and second organic compounds. It has a triplet level that is greater than the multiplet level (the energy difference between the ground state and the triplet excited state). It is preferable to select a substance that contains phosphorus. Furthermore, the first organic compound and the second organic compound contain phosphorus. An excited complex that exhibits emission that overlaps with the wavelength of the lowest energy absorption band of the photoluminescent material. It is preferable to select a combination that forms a specific shape.

[0120] Furthermore, one of the combinations of the first and second organic compounds possesses electron transport properties. By using one material and the other a material with hole transport properties, it is advantageous for the formation of excited complexes. Furthermore, the transportability of the luminescent layer can be easily adjusted by changing the content of each compound. This allows for easy control of the recombination region. The ratio of the content of materials with electron transport properties is: materials with hole transport properties: materials with electron transport properties The ratio should be 1:9 to 9:1.

[0121] The light-emitting layer 113 having the above configuration can be co-deposited by vacuum deposition or as a mixed solution. It can be fabricated using methods such as inkjet printing, spin coating, and dip coating. ru.

[0122] In this embodiment, the first light-emitting layer 113a is on the anode side, and the second light-emitting layer is on the cathode side. Although the configuration in which layer 113b is formed has been described, the stacking order can be reversed. That is, A second light-emitting layer 113b may be formed on the anode side and a first light-emitting layer 113a on the cathode side. .

[0123] Furthermore, the second light-emitting layer 113b may be further divided into two or more layers, in which case each The layers may contain different light-emitting materials. In particular, the second light-emitting layer 113b may contain the first phosphorus It is divided into two layers: a light-emitting layer and a second phosphorescent layer. The first phosphorescent layer emits red light. The emission (emission with a peak in the emission spectrum between 580 nm and 680 nm) is present in the second glue. The light-emitting layer emits green light (with a peak in the emission spectrum between 500nm and 560nm). The configuration allows for the emission of light (at 400 nm), and the first light-emitting layer 113a emits blue light (at 400 nm). If the configuration is such that emission has a peak in the emission spectrum at 480 nm, then the color rendering This is a preferred configuration because it allows for good white light emission. In this case, each The order in which the light-emitting layers are stacked is: first light-emitting layer 113a, first phosphorescent light-emitting layer, second phosphor It is preferable that the first light-emitting layer be a light-emitting layer from the viewpoint of durability of the light-emitting element, and furthermore, the first light-emitting layer 11 It is preferable for 3a to be formed on the anode side in order to obtain better characteristics.

[0124] The configuration and effects of the light-emitting layer 113 other than those described above are those described in Embodiment 1. It is the same as above. Please refer to the description of Embodiment 1.

[0125] The electron transport layer 114 is a layer containing an electron-transporting material. For example, tris(8-quinoli) Aluminum (abbreviation: Alq), Tris(4-methyl-8-quinolinolato)al Minium (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beri Rium (abbreviation: BeBq2), bis(2-methyl-8-quinolinolate)(4-phenyl Enola aluminum (abbreviation: BAlq), etc., quinoline skeleton or benzoquinoline skeleton It is a layer consisting of metal complexes having a specific property. In addition, bis[2-(2-hydroxyphenyl] [Nyl)benzoxazolate]zinc (abbreviation: Zn(BOX)2), bis[2-(2-hydro Oxazoles such as xyphenyl)benzothiazolat]zinc (abbreviation: Zn(BTZ)2) Metal complexes having thiazole ligands can also be used. In addition, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3 ,4-oxadiazole (abbreviation: PBD) and 1,3-bis[5-(p-tert-butyric acid) [Oxadiazole-2-yl]benzene (abbreviation: OXD-7) ), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), vasophenanthroline (abbreviation: BPhe n) Vasocuproine (abbreviated as BCP) can also be used. It has high electron transport properties, mainly 10 -6 cm 2 It is a substance with an electron mobility of / Vs or greater. Furthermore, the electron-transporting host material described above may be used for the electron transport layer 114.

[0126] Furthermore, the electron transport layer 114 is not limited to a single layer, but can also consist of two or more layers made of the above material. It may also be considered as a layered structure.

[0127] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layer and the light-emitting layer. This involves adding a small amount of a substance with high electron-trapping properties to a material with high electron-transporting properties as described above. This layer adjusts the carrier balance by suppressing the movement of electron carriers. This becomes possible. In such a configuration, electrons penetrate the light-emitting layer, causing emission. It is highly effective in suppressing problems that may arise (for example, a decrease in the lifespan of the device).

[0128] Furthermore, between the electron transport layer 114 and the second electrode 102, electrons are in contact with the second electrode 102. An injection layer 115 may be provided. The electron injection layer 115 may be lithium fluoride (LiF), Alkali metals such as cesium fluoride (CsF) and calcium fluoride (CaF2) or Alkaline earth metals or compounds thereof can be used. For example, those with electron transport properties. A layer made of a substance contains alkali metals, alkaline earth metals, or compounds thereof. A material having electron transport properties can be used as the electron injection layer 115. By using a layer containing alkali metals or alkaline earth metals, This is more preferable because electron injection from the second electrode 102 is performed efficiently.

[0129] The material forming the second electrode 102 has a small work function (specifically 3.8 eV) The following can be used: metals, alloys, electrically conductive compounds, and mixtures thereof. Specific examples of such cathode materials include lithium (Li) and cesium (Cs). Potassium metals, as well as magnesium (Mg), calcium (Ca), and strontium (Sr) Elements belonging to Group 1 or Group 2 of the periodic table, and alloys containing these elements (MgAg Rare earth metals such as AlLi, europium (Eu), ytterbium (Yb), and Examples include alloys containing these. However, between the second electrode 102 and the electron transport layer By providing an electron injection layer, regardless of the magnitude of the work function, Al, Ag, ITO, Ke Various conductive materials such as indium oxide-tin oxide containing ion or silicon oxide are used in the second These conductive materials can be used as electrodes 102. The film can be deposited using methods such as the stencil method and spin coating method.

[0130] Furthermore, various methods can be used to form the EL layer 103, regardless of whether they are dry or wet methods. This can be done using methods such as vacuum deposition, inkjet printing, or spin coating. It is permissible to do so. Furthermore, different film deposition methods may be used for each electrode or layer. .

[0131] The electrodes can also be formed using a wet process with the sol-gel method, or they can be formed using a metallic base material. It may also be formed by a wet method using a t. Alternatively, dry methods such as sputtering or vacuum deposition may be used. It may also be formed using [a specific method / tool].

[0132] The light-emitting element having the above configuration has a first electrode 101 and a second electrode 102 between them. The resulting potential difference causes an electric current to flow, and in the light-emitting layer 113, which is a layer containing a highly luminescent material, Holes and electrons recombine and emit light. In other words, an luminescent region is formed in the luminescent layer 113. It is structured in such a way that it can be used.

[0133] The light is emitted through either the first electrode 101 or the second electrode 102, or both. It is removed to the outside. Therefore, either the first electrode 101 or the second electrode 102 Alternatively, both may consist of light-transmitting electrodes.

[0134] The configuration of the EL layer 103 provided between the first electrode 101 and the second electrode 102 is as follows: However, it is not limited to the above. However, it is used in the light-emitting region and electrodes and carrier injection layer. To suppress quenching caused by proximity to metal, the first electrode 101 and A configuration is preferred in which a light-emitting region where holes and electrons recombine is provided at a location away from the second electrode 102. It seems so.

[0135] Furthermore, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, and especially the light emission in the light-emitting layer 113, are also important. The carrier transport layer in contact with the region is responsible for energy transfer from excitons generated in the light-emitting layer. In order to suppress this, the band gap is contained in the luminescent material that makes up the luminescent layer or in the luminescent layer. The material is composed of a material having a band gap larger than the band gap of the luminescent central material. It is preferable to do so.

[0136] The light-emitting element in this embodiment is fabricated on a substrate made of glass, plastic, or the like. That's all that's needed. As for the order of fabrication on the substrate, even if you stack them in order from the first electrode 101 side, The electrodes 102 and 2 may be stacked in order from the electrode 102 side. The light-emitting device forms one light-emitting element on one substrate. It is acceptable to have only one such light-emitting element, but it is also acceptable to form multiple light-emitting elements on a single substrate. By creating multiple of these, it is possible to create lighting devices with segmented elements or passive matrix type light-emitting devices. It can be manufactured. Also, on a substrate made of glass, plastic, etc., for example, an electric field effect can be applied. A transistor (FET) is formed, and a light-emitting element is created on an electrode electrically connected to the FET. It may be manufactured as an active matrix that controls the driving of the light-emitting element by the FET. A cub-shaped light-emitting device can be fabricated. The structure of the FET is not particularly limited. The crystallinity of the semiconductor used for T is not particularly limited; an amorphous semiconductor may also be used. Crystalline semiconductors may also be used. Furthermore, the driving circuit formed on the FET substrate may also be N It may consist of type N and type P FETs, or it may consist of an N-type FET or a P-type FET. It may be from only one of T's.

[0137] Furthermore, this embodiment can be appropriately combined with other embodiments.

[0138] Next, a light-emitting element (hereinafter also referred to as a stacked element) has a configuration in which multiple light-emitting units are stacked. The embodiment will be explained with reference to Figure 1(B). This light-emitting element has a first electrode and a second This is a light-emitting element having multiple light-emitting units between the electrodes. One light-emitting unit is shown in Figure It has a similar configuration to the EL layer 103 shown in 1(A). In other words, it has the same light emission as shown in Figure 1(A). The element is a light-emitting element having one light-emitting unit, and in this embodiment, multiple light-emitting units It can be described as a light-emitting element with knitting.

[0139] In Figure 1(B), a first light-emitting element is placed between the first electrode 501 and the second electrode 502. The knit 511 and the second light-emitting unit 512 are stacked, and the first light-emitting unit 511 A charge generation layer 513 is provided between the first electrode and the second light-emitting unit 512. Electrode 501 and the second electrode 502 correspond to the first electrode 101 and the second electrode in Figure 1(A), respectively. This corresponds to 102, and the same explanation as described in Figure 1(A) can be applied. Furthermore, even if the first light-emitting unit 511 and the second light-emitting unit 512 have the same configuration, they are different. The configuration is also acceptable.

[0140] The charge generation layer 513 contains a composite material of an organic compound and a metal oxide. The composite material of the compound and metal oxide can be used in the hole injection layer 111 shown in Figure 1(A). Composite materials can be used. For organic compounds, a hole mobility of 1 × 10⁻⁶ is possible. -6 cm 2 It is preferable to use a value of / Vs or higher. However, this is more important for hole transport than electron transport. Other substances may be used if they have high efficacy. (Example: Organic compounds and metal oxides) Because composite materials have excellent carrier implantation and carrier transport properties, they are suitable for low-voltage and low-current operation. This can be achieved. Note that when the anode side of the light-emitting unit is in contact with the charge generation layer. In this case, the charge generation layer can also play the role of the hole transport layer of the light-emitting unit, The unit does not need to have a hole transport layer.

[0141] Furthermore, the charge generation layer 513 consists of a layer containing a composite material of an organic compound and a metal oxide, and other materials. It may be formed as a laminated structure by combining with other constituent layers. For example, organic compounds A layer containing a composite material of metal oxides, and one compound selected from electron-donating materials and electrons It may also be formed by combining layers containing highly transportable compounds. A layer containing a composite material of group oxides may be formed in combination with a transparent conductive film.

[0142] In any case, the electric light sandwiched between the first light-emitting unit 511 and the second light-emitting unit 512 When a voltage is applied to the first electrode 501 and the second electrode 502, the charge generation layer 513 generates a charge on one side. Any device that injects electrons into one light-emitting unit and holes into the other light-emitting unit will suffice. For example, in Figure 1(B), the potential of the first electrode is higher than the potential of the second electrode. When a voltage is applied in this manner, the charge generation layer 513 generates electrons in the first light-emitting unit 511. Any method that injects a hole into the second light-emitting unit 512 is acceptable.

[0143] Figure 1(B) illustrates a light-emitting element having two light-emitting units, but what if there are three or more? The same principle can be applied to light-emitting devices formed by stacking multiple light-emitting units. In the form of a light-emitting element, multiple light-emitting units are placed between a pair of electrodes in a charge generation layer. By cutting and arranging the elements, high-brightness illumination is possible while maintaining a low current density, and further extending the lifespan. This enables the creation of essential components. Furthermore, it allows for the realization of light-emitting devices that can be driven at low voltage and consume low power. It is possible.

[0144] Furthermore, the configuration of the light-emitting layer 113 is such that at least one of the multiple units is... Because it is used, the manufacturing process for the unit can be reduced, This allows us to provide multi-color light-emitting elements that are advantageous for practical application.

[0145] The above configuration may be appropriately combined with other embodiments or other configurations within this embodiment. This is possible.

[0146] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting element described in Embodiment 1 or Embodiment 2 is provided. I will explain this.

[0147] In this embodiment, the light-emitting element is manufactured using the light-emitting element described in Embodiment 1 or Embodiment 2. The light-emitting device will be explained using Figure 2. Figure 2(A) is a top view showing the light-emitting device. Figure 2(B) is a cross-sectional view of Figure 2(A) cut along lines AB and CD. This light-emitting device The drive circuit section (source line drive circuit), shown by the dotted line, controls the emission of light from the light-emitting element. It includes a path (601), a pixel section (602), and a drive circuit section (gate line drive circuit) (603). 604 is the sealing substrate, 605 is the sealing material, and the area inside the sealing material 605 is a space. It's set to 607.

[0148] The routing wiring 608 is connected to the source line drive circuit 601 and the gate line drive circuit 603. FPC (Flexible Printed Circuit) is a wiring used to transmit signals and serves as an external input terminal. (Lindt Circuit) Video signal, clock signal, start signal, reset signal from 609 Receives, etc. Note that only FPC is shown in the diagram here, but this FPC has print A circuit board (PWB) may be attached. The light-emitting device in this specification includes light-emitting This includes not only the device itself, but also the state in which the FPC or PWB is attached to it. do.

[0149] Next, the cross-sectional structure will be explained using Figure 2(B). The drive circuit is located on the element substrate 610. A section and a pixel section are formed, but here, the source line drive circuit 601 is the drive circuit section. This shows one of the pixels in the pixel section 602.

[0150] The source line drive circuit 601 consists of an n-channel FET 623 and a p-channel FET 62 A CMOS circuit is formed by combining it with 4. In addition, the drive circuit is a variety of CMOS circuits It may also be formed using PMOS or NMOS circuits. In this embodiment, the substrate The image above shows a driver integrated with a drive circuit, but this is not always necessary; the drive circuit can be... It can also be formed on an external surface rather than on the substrate.

[0151] Furthermore, the pixel section 602 includes a switching FET 611 and a current control FET 612 and It is formed by a plurality of pixels, each including a first electrode 613 electrically connected to a drain. Furthermore, an insulator 614 is formed covering the end of the first electrode 613. Here, positive It is formed by using a photosensitive acrylic resin film of a mold.

[0152] Furthermore, a curved surface with curvature is formed at the upper or lower end of the insulator 614. Preferably, when positive-type photosensitive acrylic is used as the material for the insulator 614. In addition, the upper end of the insulator 614 has a curved surface with a radius of curvature (0.2 μm to 3 μm). The insulating material 614 may be either a negative-type photosensitive resin or a positive-type photosensitive resin. It can be used.

[0153] An EL layer 616 and a second electrode 617 are formed on the first electrode 613, respectively. Here, the material used for the first electrode 613 which functions as an anode is, work function It is desirable to use a material with a large ion content. For example, ITO film or silicon-containing ink Dium-tin oxide film, indium oxide film containing 2 to 20 wt% zinc oxide, titanium nitride film In addition to single-layer films such as chromium films, tungsten films, Zn films, and Pt films, titanium nitride films and aluminum films are also available. Lamination with a film mainly composed of nium, titanium nitride film and aluminum-based film and nitride A three-layer structure with a titanium film can be used. Furthermore, if a laminated structure is used, the wiring... It has low resistance, provides good ohmic contact, and can even function as an anode. Cut.

[0154] Furthermore, the EL layer 616 can be coated using a deposition method with a deposition mask, an inkjet method, or a spin coat. It is formed by various methods such as the law. The EL layer 616 is formed by Embodiment 1 or Embodiment 2 It includes the configuration described above. Furthermore, other materials constituting the EL layer 616 include: It may be a low-molecular-weight compound or a high-molecular-weight compound (including oligomers and dendrimers). .

[0155] Furthermore, the material used for the second electrode 617, which is formed on the EL layer 616 and functions as a cathode As for materials, materials with a low work function (Al, Mg, Li, Ca, or alloys of these) It is preferable to use a compound such as MgAg, MgIn, AlLi. Note that the EL layer 6 If the light generated in 16 passes through the second electrode 617, then the second electrode 617 is a film. A thin metal film with reduced thickness and a transparent conductive film (ITO, containing 2 to 20 wt% zinc oxide). Lamination with indium, silicon-containing indium tin oxide, zinc oxide (ZnO), etc. It is good to use it.

[0156] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element. The light-emitting element is a light-emitting element having the configuration of Embodiment 1 or Embodiment 2. The pixel portion is formed by multiple light-emitting elements, but in this embodiment The optical device has a light-emitting element as described in Embodiment 1 or Embodiment 2, and other configurations. It may include both the light-emitting element and the light-emitting element.

[0157] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, A light-emitting element is placed in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The structure is equipped with child 618. Furthermore, the space 607 is filled with a filler material. In addition to cases where an inert gas (such as nitrogen or argon) is filled, it is also filled with sealant 605. In some cases, a recess is formed in the sealing substrate and a desiccant 625 is placed there, which reduces the effects of moisture. This configuration is preferable because it can suppress deterioration caused by [unspecified factor].

[0158] Furthermore, it is preferable to use epoxy resin or glass frit for the sealant 605. Furthermore, it is desirable that these materials be as impermeable to moisture and oxygen as possible. In addition to glass substrates and quartz substrates, FRP (Fiber Reinforced Plastic) is also used as a material for the sealing substrate 604. Reinforced Plastics, PVF (polyvinyl fluoride), polyethylene A plastic substrate made of sterling silver or acrylic can be used.

[0159] As described above, a light-emitting element is manufactured using the light-emitting element described in Embodiment 1 or Embodiment 2. A light-emitting device can be obtained.

[0160] Figure 3 shows a light-emitting element that emits white light, and a colored layer (color filter), etc. An example of a light-emitting device that has been made full-color by the above is shown. Figure 3(A) shows substrate 1001, underlay insulation Edge film 1002, gate insulating film 1003, gate electrodes 1006, 1007, 1008, 1 The interlayer insulating film 1020, the second interlayer insulating film 1021, the peripheral portion 1042, the pixel portion 1040, Drive circuit section 1041, first electrodes 1024W, 1024R, 1024G, 10 24B, partition wall 1025, EL layer 1028, second electrode 1029 of light-emitting element, sealing substrate 10 31. The sealing material 1032 and other components are shown in the illustration.

[0161] Furthermore, in Figure 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue) are shown. The colored layer (1034B) is provided on the transparent substrate (1033). In addition, the black layer (black mat) A further component (Tricks) 1035 may be provided. A transparent substrate having a colored layer and a black layer. 1033 is aligned and fixed to the substrate 1001. Note that the colored layer and the black layer are O It is covered with a supercoat layer 1036. Also, in Figure 3(A), light penetrates the colored layer. There is a light-emitting layer that allows light to escape to the outside without passing through, and a light-emitting layer that allows light to escape to the outside by passing through the colored layers of each color. Light that does not pass through the colored layer is white, and light that passes through the colored layer is red, blue, and green, thus producing four colors. Images can be represented using pixels.

[0162] Figure 3(B) shows the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer Example of forming layer 1034B) between the gate insulating film 1003 and the first interlayer insulating film 1020. This was shown. Thus, the colored layer is provided between the substrate 1001 and the sealing substrate 1031. That's good too.

[0163] Furthermore, in the light-emitting device described above, light is taken to the substrate 1001 side on which the FET is formed. Although the light-emitting device was designed with a bottom-emission structure, the light-emitting element was directed towards the sealing substrate 1031. It can also be used as a light-emitting device with an extraction structure (top emission type). Top emission type A cross-sectional view of the light-emitting device is shown in Figure 4. In this case, the substrate 1001 is a substrate that does not transmit light. This is possible. Until the connecting electrode that connects the FET and the anode of the light-emitting element is fabricated, the bottom It is formed in the same way as an emission-type light-emitting device. Then, the third interlayer insulating film 1037 is attached to the electrode. It is formed covering 1022. This insulating film may also play a planarizing role. Third interlayer The insulating film 1037 is formed using the same material as the second interlayer insulating film, as well as various other materials. It is possible.

[0164] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are positive here. This is referred to as the electrode, but it can also be the cathode. Furthermore, top-emission type light emission as shown in Figure 4 is also possible. In the case of a device, it is preferable that the first electrode be a reflective electrode. The configuration of the EL layer 1028 is The configuration is as described as the EL layer 103 in Embodiment 1 or Embodiment 2, Furthermore, the element structure is designed to produce white light emission.

[0165] In the top emission structure shown in Figure 4, the colored layer (red colored layer 1034R, green colored layer) The sealing is performed using a sealing substrate 1031 having a colored layer 1034G and a blue colored layer 1034B. This can be done. The encapsulating substrate 1031 has a black layer positioned between the pixels. A matrix 1035 may be provided. Colored layer (red colored layer 1034R, green colored layer Layer 1034G, the blue colored layer 1034B, and the black layer (black matrix) 1035 are It may be covered with an overcoat layer. The encapsulating substrate 1031 is translucent. A circuit board will be used.

[0166] Furthermore, while we have shown an example of full-color display using four colors—red, green, blue, and white—this is not particularly limited to... Alternatively, full-color display may be performed using three colors: red, green, and blue.

[0167] The light-emitting device in this embodiment uses the light-emitting element described in Embodiment 1 or Embodiment 2. Because it is used, a light-emitting device with good characteristics can be obtained. Specifically, the implementation The light-emitting element shown in Embodiment 1 or Embodiment 2 is a light-emitting element with good luminous efficiency and low power consumption. It can be used as a light-emitting device with reduced noise. Furthermore, it is a light-emitting element that is easy to mass-produce and inexpensive. We can provide a light-emitting device.

[0168] Up to this point, we have explained active matrix type light-emitting devices, but from here on we will discuss... This section describes a sib matrix type light-emitting device. Figure 5 shows a pack fabricated by applying the present invention. This shows a sib matrix type light-emitting device. Note that Figure 5(A) is a perspective view showing the light-emitting device, Figure 5 (B) is a cross-sectional view of Figure 5(A) taken along the XY line. In Figure 5, on the substrate 951 An EL layer 955 is provided between electrode 952 and electrode 956. The end of electrode 952 It is covered with an insulating layer 953. And a partition layer 954 is provided on top of the insulating layer 953. The side walls of the partition layer 954, as they approach the substrate surface, have a certain degree of separation between one side wall and the other side wall. It has a slope that narrows as the spacing decreases. In other words, the cross-section of the partition layer 954 in the short-side direction is It is trapezoidal in shape, with the base (facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) The upper edge (the side that faces the same direction as the plane direction of the insulating layer 953 and does not come into contact with the insulating layer 953) It is shorter than ). In this way, by providing the partition layer 954, light-emitting elements caused by static electricity, etc. This can prevent defects. Also, in passive matrix type light-emitting devices, the implementation is It uses a light-emitting element with good luminous efficiency as shown in Embodiment 1 or Embodiment 2, and has low power consumption. It can be a reduced-power light-emitting device. Furthermore, this light-emitting element is a light-emitting element that is easy to mass-produce. Therefore, we can provide an inexpensive light-emitting device.

[0169] The light-emitting device described above uses a number of tiny light-emitting elements arranged in a matrix. Because it can be controlled, it can be suitably used as a display device for representing images. It is a light device.

[0170] Furthermore, this embodiment can be freely combined with other embodiments.

[0171] (Embodiment 4) In this embodiment, the light-emitting element described in Embodiment 1 or Embodiment 2 is used as an illumination device. An example of its use will be explained with reference to Figure 6. Figure 6(B) is a top view of the lighting device, and Figure 6(A) is This is a cross-sectional view of ef in Figure 6(B).

[0172] The lighting device in this embodiment has a light-transmitting substrate 400 which is a support, and a first An electrode 401 is formed. The first electrode 401 is the first electrode 1 in Embodiment 1. This corresponds to 01. When light is extracted from the first electrode 401 side, the first electrode 401 is light-transmitting. It is formed from a material that possesses certain properties.

[0173] A pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0174] An EL layer 403 is formed on the first electrode 401. The EL layer 403 is in Embodiment 1 The configuration of the EL layer 103, or the light-emitting units 511, 512 and the charge generation layer 513 This corresponds to a combined configuration, etc. Please refer to the relevant description for details on these configurations.

[0175] The EL layer 403 is covered to form the second electrode 404. The second electrode 404 is in Embodiment 1 This corresponds to the second electrode 102 in the diagram. When light emission is taken from the first electrode 401 side, The second electrode 404 is formed from a highly reflective material. The second electrode 404 is attached to the pad 41 By connecting to 2, voltage is supplied.

[0176] The above describes a light-emitting element having a first electrode 401, an EL layer 403, and a second electrode 404. The lighting device shown in the embodiment has a light-emitting element with high luminous efficiency. Therefore, the lighting device in this embodiment can be a lighting device with low power consumption.

[0177] The light-emitting element having the above configuration is sealed to a substrate 407 using sealing materials 405 and 406. The lighting device is completed by attaching and sealing it. Either sealing material 405 or 406 is used. Either way is fine. Also, the inner sealing material 406 (not shown in Figure 6(B)) contains a desiccant. It can also be mixed in, which allows it to absorb moisture and leads to improved reliability. .

[0178] Furthermore, the pad 412 and a portion of the first electrode 401 are extended outside the sealing materials 405 and 406. By providing it, it can be used as an external input terminal. Also, a converter can be placed on top of it. An IC chip 420 or similar, which incorporates such features, may also be provided.

[0179] As described above, the lighting device described in this embodiment has an EL element in either Embodiment 1 or Embodiment 2. Because it has the described light-emitting element, it can be used as a lighting device with low power consumption. This allows for lighting devices with low driving voltages. Furthermore, it allows for inexpensive lighting devices. ru.

[0180] (Embodiment 5) In this embodiment, the light-emitting element described in Embodiment 1 or Embodiment 2 is included as a part thereof. Examples of electronic devices will be described. The light-emitting element described in Embodiment 1 or Embodiment 2 emits light. This light-emitting element has good efficiency and reduced power consumption. As a result, the following is described in this embodiment. The electronic device can be an electronic device having a light-emitting part with reduced power consumption. Furthermore, the light-emitting element described in Embodiment 1 or Embodiment 2 is a light-emitting element with a small number of film-forming layers. Therefore, it is possible to make it an inexpensive electronic device.

[0181] Examples of electronic devices to which the above light-emitting element is applied include television equipment (television, or television). (also called a revision receiver), monitors for computers, digital cameras, digital Video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) ), portable game consoles, personal digital assistants, sound playback devices, large game machines such as pachinko machines, etc. These include [examples of electronic devices]. Specific examples of these electronic devices are shown below.

[0182] Figure 7(A) shows an example of a television system. The television system is housed in a 710 enclosure. The display unit 7103 is incorporated into part 1. Also, the housing is connected by the stand 7105. This shows the configuration supporting 7101. The display unit 7103 can display video. The display unit 7103 is capable of composing the light-emitting element described in Embodiment 1 or Embodiment 2. They are arranged in a camphor-like pattern.

[0183] The television equipment is operated using the control switches on the housing 7101 or a separate remote control. This can be done using the device 7110. The remote control device 7110 has an operation key 7109. This allows you to control the channel and volume, and the video displayed on the display unit 7103 It can be operated. Also, the remote control unit 7110 A display unit 7107 that displays the information output from the unit may also be provided.

[0184] The television system shall consist of a receiver, modem, etc. It can receive television broadcasts, and also communicate via wired or wireless connection through a modem. By connecting to a network, one-way (sender to receiver) or two-way (sender to receiver) communication is possible. It is also possible to communicate information between recipients, or between recipients themselves.

[0185] Figure 7(B1) is a computer, consisting of the main unit 7201, the casing 7202, the display unit 7203, and a key - Includes board 7204, external connection port 7205, pointing device 7206, etc. Furthermore, this computer is similar to the one described in Embodiment 1 or Embodiment 2. It is manufactured by arranging optical elements in a matrix and using them in the display unit 7203. (Figure 7) The computer in B1) may take the form shown in Figure 7(B2). The computer uses a second keyboard 7204 and a pointing device 7206 instead of the first one. A display unit 7210 is provided. The second display unit 7210 is a touch panel type. By operating the input display shown on the second display unit 7210 with a finger or a special pen, This allows input. In addition, the second display unit 7210 not only displays input, but also... It is also possible to display other images. Furthermore, the display unit 7203 is a touch panel. Good. The two screens are connected by a hinge, which makes it easier to store and transport the device. This also prevents problems such as scratches and damage. The data is displayed by arranging the light-emitting elements described in Embodiment 1 or Embodiment 2 in a matrix. It is manufactured by using it in part 7203.

[0186] Figure 7(C) shows a portable gaming machine, which consists of two cabinets, cabinet 7301 and cabinet 7302. The housing 7301 is connected in an openable and closable manner by the connecting part 7303. Display unit manufactured by arranging the light-emitting elements described in Embodiment 1 or Embodiment 2 in a matrix. The 7304 is incorporated, and the display unit 7305 is incorporated into the housing 7302. The portable gaming machine shown in 7(C) also includes a speaker unit 7306 and a recording medium insertion unit 7307. LED lamp 7308, input means (operation key 7309, connection terminal 7310, sensor 73 11 (Force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical Chemical substances, sound, time, hardness, electric field, electric current, voltage, power, radiation, flow rate, humidity, gradient, vibration Equipped with a function to measure odor or infrared radiation, a microphone (7312), etc. Of course, the configuration of a portable gaming machine is not limited to those described above, and at least the display unit 73 Both or either of 04 and the display unit 7305 are described in Embodiment 1 or Embodiment 2. It is sufficient to use a display unit made by arranging light-emitting elements in a matrix, and other accessories The configuration can be configured with appropriate equipment. The portable gaming machine shown in Figure 7(C) has a recording medium Functions that read programs or data stored in the body and display them on the display unit, and other portable devices It has the function of sharing information by communicating wirelessly with a mobile gaming machine. The functions of a belt-type gaming machine are not limited to these, and it can have a variety of functions.

[0187] Figure 7(D) shows an example of a mobile phone. The mobile phone is incorporated into the housing 7401. In addition to the display unit 7402, there are operation buttons 7403, an external connection port 7404, and a speaker 74 05, It is equipped with a microphone 7406, etc. Note that the mobile phone is Embodiment 1 or the embodiment The display unit 7402 is made by arranging the light-emitting elements described in Embodiment 2 in a matrix. ru.

[0188] The mobile phone shown in Figure 7(D) allows information to be entered by touching the display unit 7402 with a finger or the like. It is also possible to configure it so that you can make a phone call or compose an email. Operations such as this can be performed by touching the display unit 7402 with a finger or the like.

[0189] The display unit 7402 has three main modes. The first is a display that primarily displays images. The first mode is display mode, the second is input mode which is primarily for inputting information such as characters. The third is display mode. This is a display + input mode, which is a combination of two modes: display mode and input mode.

[0190] For example, when making a phone call or composing an email, the display unit 7402 is used for text input. The primary mode is text input, and you should perform the input operation for the characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402. It seems so.

[0191] Furthermore, the mobile phone has sensors inside that detect tilt, such as a gyroscope and an accelerometer. By providing an output device, the orientation of the mobile phone (vertical or horizontal) is determined, and the image of the display unit 7402 is displayed accordingly. The display can be set to switch automatically.

[0192] Furthermore, screen modes can be switched by touching the display unit 7402 or by operating the housing 7401. This is done by operating button 7403. Also, the type of image displayed on display unit 7402 Therefore, it is also possible to switch between them. For example, the image signal displayed on the display unit is a video signal. Switch to display mode if it's data, or to input mode if it's text data.

[0193] Furthermore, in input mode, the signal detected by the optical sensor of the display unit 7402 is detected and displayed If there is no touch input on unit 7402 for a certain period of time, the screen mode will be changed to input mode. You may also control the system to switch from this mode to display mode.

[0194] The display unit 7402 can also function as an image sensor. For example, the display unit 74 By touching device 02 with the palm or fingers, the user can be authenticated by capturing images of their palm print, fingerprints, etc. Furthermore, the display unit may have a backlight that emits near-infrared light or a sensing light that emits near-infrared light. Using the appropriate source, it is also possible to image finger veins, palmar veins, and other veins.

[0195] The configuration shown in this embodiment is a combination of the configurations shown in Embodiments 1 to 4 as appropriate. They can be used together.

[0196] As described above, the scope of application of the light-emitting device equipped with the light-emitting element described in Embodiment 1 or Embodiment 2 Its applications are extremely broad, making it possible to apply this light-emitting device to electronic equipment in all fields. By using the light-emitting element described in Embodiment 1 or Embodiment 2, power consumption can be reduced. You can obtain advanced electronic devices.

[0197] Figure 8 shows a liquid crystal light source as described in Embodiment 1 or Embodiment 2 applied to a backlight. This is an example of a liquid crystal display device. The liquid crystal display device shown in Figure 8 consists of a housing 901, a liquid crystal layer 902, and It has a light unit 903 and a housing 904, and the liquid crystal layer 902 has a driver IC 905 and It is connected. Also, the backlight unit 903 is in Embodiment 1 or Embodiment The light-emitting element described in 2 is used, and current is supplied via terminal 906.

[0198] Apply the light-emitting element described in Embodiment 1 or Embodiment 2 to the backlight of a liquid crystal display device. As a result, a backlight with reduced power consumption can be obtained. Also, in Embodiment 2 By using the described light-emitting element, a surface-emitting illumination device can be fabricated, and it is also possible to scale it up to a large area. This makes it possible to increase the backlight area, and also to increase the liquid crystal display area. Furthermore, the light-emitting device to which the light-emitting element described in Embodiment 2 is applied has a thickness compared to the conventional device. Because it can be made smaller, it also becomes possible to make display devices thinner.

[0199] Figure 9 shows the light-emitting element described in Embodiment 1 or Embodiment 2 connected to an electrical station, which is a lighting device. This is an example of its use in a lamp. The lamp shown in Figure 9 has a housing 2001 and a light source 2002. Furthermore, the lighting device described in Embodiment 4 is used as the light source 2002.

[0200] Figure 10 shows the light-emitting element described in Embodiment 1 or Embodiment 2 in an indoor lighting device 300. This is an example of its use as 1. The light-emitting element described in Embodiment 1 or Embodiment 2 has a power consumption of Because the light-emitting element is reduced, it can be used as a lighting device with reduced power consumption. Furthermore, since the light-emitting element described in Embodiment 1 or Embodiment 2 can be made to have a large area, It can be used as a lighting device for stacks. Also, as described in Embodiment 1 or Embodiment 2. Because the light-emitting element is thin, it can be used in a miniaturized lighting device.

[0201] The light-emitting element described in Embodiment 1 or Embodiment 2 is used in automobile windshields and dash windows. It can also be mounted on a board. Figure 11 shows the light-emitting element described in Embodiment 2 on an automobile. This shows one embodiment for use on the windshield and dashboard. Display area 5000 to display area 5005 is a display provided using the light-emitting element described in Embodiment 1 or Embodiment 2. ru.

[0202] Display area 5000 and display area 5001 are provided in an actual form on the windshield of an automobile. This is a display device equipped with a light-emitting element as described in Embodiment 1 or Embodiment 2. The light-emitting element described in embodiment 2 is made of a first electrode and a second electrode made of a light-transmitting electrode. This will result in a display device that is transparent, allowing the other side to be seen through, a so-called see-through display device. This is possible. If the display is see-through, even if it is installed on the windshield of a car. It can be installed without obstructing the view. Furthermore, the transistor used for driving is When providing such a device, organic transistors made of organic semiconductor materials or oxide semiconductors are used. It is best to use transistors that are transparent to light, such as transistors.

[0203] The display area 5002 is provided in the pillar portion as described in Embodiment 1 or Embodiment 2. This is a display device equipped with an optical element. The display area 5002 is an imaging means provided on the vehicle body. By displaying these images, the view obstructed by the pillars can be compensated for. Similarly, the display area 5003 provided on the dashboard is obscured by the vehicle body. The blind spots are compensated for by displaying images from imaging devices installed on the outside of the vehicle. This can enhance safety. By projecting images to complement the parts that are not visible, This allows for a more natural and seamless safety check.

[0204] Display areas 5004 and 5005 display navigation information, speedometer, tachometer, and driving information. It can provide various information such as distance, fuel level, gear status, and air conditioning settings. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in display areas 5000 to 5003. Furthermore, display areas 5000 to 5005 can also be used as lighting devices. ru.

[0205] The light-emitting element described in Embodiment 1 or Embodiment 2 is a light-emitting element with high luminous efficiency. This is possible. Furthermore, it allows for the creation of light-emitting elements with low power consumption. Therefore, the display area Even if many large screens are provided in area 5000 or display area 5005, it puts a load on the battery. Because it is less likely to cause discomfort and can be used comfortably, Embodiment 1 or Embodiment 2 The light-emitting device or lighting device using the light-emitting element described above is a vehicle-mounted light-emitting device or lighting device. It can be used suitably in this way.

[0206] Figures 12(A) and 12(B) show examples of foldable tablet devices. 2(A) is in the open state, and the tablet terminal consists of a housing 9630 and a display unit 9631a Display unit 9631b, display mode switching switch 9034, power switch 9035, It has a power mode selector switch 9036, a fastener 9033, and an operation switch 9038. The tablet terminal is equipped with the light-emitting element described in Embodiment 1 or Embodiment 2. By using the light-emitting device in either or both of the display unit 9631a and the display unit 9631b It is made.

[0207] The display unit 9631a can be partially designated as a touch panel area 9632a, and the display will be Data can be entered by touching the operation key 9637. Note that the display unit 963 In 1a, as an example, one half of the area has a display-only function, and the other half of the area The diagram shows a configuration that includes touch panel functionality, but is not limited to this configuration. Display unit 963 The entire area of ​​1a may also be configured to have touch panel functionality. For example, the display unit 96 The entire surface of 31a is used as a touch panel with keyboard buttons, and the display unit 9631b is displayed. It can be used as a screen.

[0208] In addition, in the display unit 9631b, similar to the display unit 9631a, one of the display units 9631b The section can be designated as the touch panel area 9632b. Additionally, the touch panel keyboard... By touching the location where the display switch button 9639 is displayed with your finger or stylus, Keyboard buttons can be displayed on the display unit 9631b.

[0209] Furthermore, if you touch the touch panel area 9632a and the touch panel area 9632b simultaneously... You can also input "chi".

[0210] Additionally, the display mode switch 9034 selects the display orientation, such as portrait or landscape. You can switch between modes, such as black and white or color display. Power saving mode switching. Switch 9036 is detected by an optical sensor built into the tablet device when it is in use. The display brightness can be optimized according to the amount of light. In addition to sensors, other detection devices such as gyroscopes, accelerometers, and other sensors that detect tilt It may be built-in.

[0211] Furthermore, Figure 12(A) shows an example where the display area of ​​display unit 9631b and display unit 9631a are the same. However, this is not particularly limited, and one size may be different from the other. The quality of the display may also differ. For example, one display panel can provide a higher resolution display than the other. You can also use "ru".

[0212] Figure 12(B) shows the closed state, and in this embodiment, the tablet terminal has a casing. Body 9630, solar cell 9633, charge / discharge control circuit 9634, battery 9635, DCD An example is shown that includes a C converter 9636. Note that in Figure 12(B), the charge / discharge control circuit 963 As an example of 4, consider a configuration having a battery 9635 and a DC-DC converter 9636. It is showing.

[0213] Note that the tablet device is foldable, so when not in use, the casing 9630 is closed. This can be done. Therefore, the display units 9631a and 9631b can be protected. We can provide tablet devices that are highly durable and reliable from a long-term use perspective.

[0214] In addition, the tablet devices shown in Figures 12(A) and 12(B) are also available in various forms. Functions to display information (still images, videos, text images, etc.), calendar, date or time, etc. A function that displays information on the display unit, and a touch input operation or editing of the information displayed on the display unit. It has input capabilities, and functions to control processing through various software (programs), etc. It is possible.

[0215] The touch panel is powered by a solar cell 9633 mounted on the surface of the tablet device. It can be supplied to the display unit or the video signal processing unit, etc. Note that the solar cell 9633 is If provided on one or two sides of the housing 9630, efficient charging of the battery 9635 This configuration is preferable because it allows for the following actions to be performed.

[0216] Furthermore, the configuration and operation of the charge / discharge control circuit 9634 shown in Figure 12(B) are shown in Figure 12( A block diagram is shown and explained in C). Figure 12(C) shows solar cell 9633, battery 9 635, DC-DC converter 9636, converter 9638, switch SW1 to SW3 The display unit 9631 is shown, along with the battery 9635 and the DC-DC converter 963 6. Converter 9638 and switches SW1 to SW3 control the charge and discharge as shown in Figure 12(B). This corresponds to circuit 9634.

[0217] First, let's explain an example of how the solar cell 9633 operates when generating electricity using ambient light. The electricity generated by the solar panel is converted to DC to provide the voltage needed to charge the 9635 battery. The DC converter 9636 performs either a boost or a buck. Then, the display unit 9631 operates as follows: When power charged by solar cell 9633 is used, turn on switch SW1. The converter 9638 will boost or lower the voltage to the required level for the display unit 9631. When you do not want to display anything on the display unit 9631, turn SW1 off and turn SW2 on. The configuration should be designed to charge the 9635 battery.

[0218] While the solar cell 9633 is shown as an example of a power generation method, the power generation method is not particularly limited. It is not limited to other power generation devices such as piezoelectric elements (piezoelectric elements) and thermoelectric elements (Peltier elements). The battery 9635 may be charged by some means. A contactless power transmission module that charges by sending and receiving power, or a combination of other charging methods. This configuration is also acceptable, and it does not require a means of generating electricity.

[0219] Furthermore, if the above-mentioned display unit 9631 is included, it is a tablet terminal with the shape shown in Figure 12. Not limited to this. [Examples]

[0220] In this embodiment, a light-emitting element (light-emitting element 1) according to one aspect of the present invention will be described. Element 1 consists of a fluorescent light-emitting layer (first light-emitting layer 113a) and a phosphorescent light-emitting layer (second light-emitting layer 113b). It has a light-emitting layer 113 formed by contact with a phosphorescent light-emitting layer (second light-emitting layer 113b) It consists of a first phosphorescent layer (second phosphorescent layer 113b-1) that exhibits red phosphorescence, and a green glue. It consists of a lamination with a second phosphorescent layer (second light-emitting layer 113b-2) that exhibits light emission. The structural formula of the organic compound used in light-emitting element 1 is shown below.

[0221] [ka]

[0222] The method for fabricating the light-emitting element 1 of this embodiment is shown below.

[0223] (Method for fabricating light-emitting element 1) First, indium tin oxide (ITSO) containing silicon oxide is sputtered onto a glass substrate. The first electrode 101 was formed by depositing a film using the 3D method. The film thickness was set to 110 nm. The area was set to 2 mm x 2 mm. Here, the first electrode 101 functions as the anode of the light-emitting element. It is an electrode.

[0224] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0225] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate was left for approximately 30 minutes. It was allowed to cool.

[0226] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After applying pressure, the above structural formula (i) is applied to the first electrode 101 by a vapor deposition method using resistance heating. 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophen By co-depositing (abbreviation: DBT3P-II) and molybdenum(VI) oxide, holes An injection layer 111 was formed. Its film thickness was set to 40 nm, and it was made of DBT3P-II and molybdenum oxide. The ratio of ingredients is adjusted to be 4:2 by weight (=DBT3P-II:molybdenum oxide). Co-evaporation is a method of vapor deposition in which multiple evaporation sources are used to deposit vapor simultaneously within a single processing chamber. It is the law.

[0227] Next, on the hole injection layer 111, 9-phenyl-3-[4, represented by the above structural formula (ii), is injected. -(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCz) A film of PA was deposited to a thickness of 20 nm to form a hole transport layer 112.

[0228] Furthermore, on the hole transport layer 112, 7-[4-(10-F, represented by the above structural formula (iii)) [phenyl-9-antryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and N,N'-bis(3-methylphen) represented by the above structural formula (iv) (Lu)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl] -Pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) and by weight ratio 1: 10nm so that the value becomes 0.04 (=cgDBCzPA:1,6mMemFLPAPrn) A fluorescent emitting layer (first emitting layer 113a) was formed by co-deposition. Subsequently, the above structural formula (v) Represented as 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibe Nzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and the above structural formula (v i) is represented by N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl- 9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2 -amine (abbreviation: PCBBiF) and (dipivaloyl methyl amine) represented by the above structural formula (vii). Thanato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [ Ir(tppr)²(dpm)]) and a weight ratio of 0.6:0.4:0.05 (=2mDB) So that it becomes TBPDBq-II:PCBBiF:[Ir(tppr)2(dpm)]) A 5nm co-deposit was performed to form the first phosphorescent emitting layer (second emitting layer 113b-1), and then 2 mDBTBPDBq-II and PCBBiF and the screw represented by the above structural formula (viii) [2 -(6-tert-butyl-4-pyrimidinyl-κN3)phenyl-κC](2,4-pe Ntanzionato-κ 2 O,O') Iridium(III) (Abbreviation: [Ir(tBuppm) 2(acac)]) and the weight ratio 0.8:0.2:0.05 = (=2mDBTBPDBq -II:PCBBiF:[Ir(tBuppm)2(acac)]) so that 20n The second phosphorescent layer (second phosphorescent layer 113b-2) is formed by co-depositing m. A second light-emitting layer (113b) was formed.

[0229] Furthermore, in the phosphorescent emitting layer (second emitting layer 113b), 2mDBTBPDBq-II PCBBiF forms an excited complex with 2mDBTBPDBq-II. The photoluminescence wavelength of the co-evaporated film (i.e., the emission wavelength of the excited complex) is 515 nm. It is in the vicinity. Also, the emission wavelengths are [Ir(tppr)2(dpm)] and [Ir(tB It overlaps with the longest wavelength absorption band of uppm)2(acac), and the energy transfer efficiency is It has a high configuration.

[0230] Furthermore, the singlet excitation energy of cgDBCzPA, the host material of the fluorescence emission layer, is Larger than the singlet excitation energy of the fluorescent material 1,6mMemFLPAPrn Furthermore, the triplet excitation energy of cgDBCzPA is 1,6mMemFLPAPrn The relationship is that it is smaller than the triplet excitation energy, and the fluorescence emission layer (first emission layer 113 a) Regeneration and emission of singlet excitons associated with triplet-triplet anihelization are obtained. It has a pyramidal structure. In fact, the generation of delayed fluorescence was confirmed in this structure.

[0231] Subsequently, a film thickness of 2mDBTBPDBq-II is applied to the phosphorescent layer (second light-emitting layer 113b). A film was deposited to a thickness of 10 nm, and further, the bathophenantho represented by the above structural formula (ix) was added. A phosphorus (abbreviated as BPhen) film is deposited to a thickness of 15 nm to form an electron transport layer 114. Ta.

[0232] After forming the electron transport layer 114, lithium fluoride (LiF) is then applied to a thickness of 1 nm. A layer is deposited to form an electron injection layer 115, and finally, a second electrode 1 that functions as a cathode is formed. As O2, aluminum is deposited to a film thickness of 200 nm, thus in this embodiment A light-emitting element 1 was fabricated.

[0233] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0234] The light-emitting element 1 is placed in a glove box under a nitrogen atmosphere, and is not exposed to the air. The process involves sealing with a substrate (applying a sealing material around the element, and then UV treatment at 80°C during sealing). After heat treatment (1 hour) at room temperature (25°C), reliability was measured. It was done in an atmosphere maintained at a constant temperature (°C).

[0235] Figure 13 shows the current density-luminance characteristics of light-emitting element 1, and Figure 14 shows the luminance-current efficiency characteristics, and the voltage-luminance characteristics. The intensity characteristics are shown in Figure 15, the luminance-external quantum efficiency characteristics in Figure 16, and the emission spectrum in Figure 17. .

[0236] As described above, the light-emitting element 1 has a structure that does not use an intermediate layer, yet it has a light emission of 1000 cd / m². 2 Attached It was found to exhibit good luminescence efficiency, with a current efficiency of approximately 30 cd / A and an external quantum efficiency of approximately 13%. Furthermore, the operating voltage is low, in the 3V range.

[0237] Furthermore, from the emission spectrum, red emission originating from [Ir(tppr)2(dpm)] and [ Green emission derived from Ir(tBuppm)2(acac) and 1,6mMemFLPAPr Blue emission originating from n was observed. From this, it was determined that the fluorescent emission layer (first emission layer 113a) and Sufficient light emission is obtained from both sides of the biphosphor photoluminescent layer (second light-emitting layer 113b). This can be understood. Also, the light-emitting element 1 has a density of 1000 cd / m². 2 The correlated color temperature in the vicinity is 3130K. With an average color rendering index of 92, the color temperature is sufficient for lighting applications and is very good. It was also found to be an element with color rendering properties.

[0238] Next, the initial brightness was set to 5000 cd / m². 2 The light-emitting element 1 is driven under the condition of constant current density. The results of the reliability test are shown in Figure 18. Figure 18 shows the results with the initial brightness set to 100%. This shows the change in graded brightness. From this result, it can be seen that the light-emitting element 1 maintains its initial brightness even after 62 hours. It maintains 94% of its original brightness and exhibits minimal brightness degradation over time, making it a highly reliable light-emitting element. It turned out to be a child.

[0239] Here, the single cgDBCzPA and 1,6mMemFLPArn used in the light-emitting element 1. The number excitation levels (S1 level) are 2.95 eV and 2.68 eV, respectively, from the absorption edge of the deposited film. It was estimated to be eV.

[0240] Furthermore, in this embodiment, the 2mDBTBPDBq-II and PCBB used in the light-emitting element 1 Triplet levels (T1 level) of iF, cgDBCzPA, and 1,6mMemFLPAPrn The results of the measurements for ) are shown in Table 1. To measure the T1 level, the phosphorescence emission of each substance is measured. This was determined by the following: The measurement conditions involved irradiating each substance with 325 nm excitation light and measuring the temperature. Measurements were taken at 10K. For measuring energy levels, it is better to calculate from the absorption wavelength rather than the emission wavelength. Although the accuracy is high, the absorption at the T1 level is extremely weak, making measurement difficult. The phosphorescence peak wavelength located on the shortest wavelength side was defined as the T1 level. Therefore, the measured values This should include some margin of error. Furthermore, cgDBCzPA and 1,6mMemFLPA Regarding Prn, intersystem cross-relationships are less likely to occur, so tris(2-phenylpyridinato)yl By adding (co-depositing) zinc (abbreviated as Ir(ppy)3) as a sensitizer, phosphorescence occurs. Light was observed.

[0241] [Table 1]

[0242] Based on the above results, in the fluorescence emission layer of the light-emitting element 1, the host material cgDBCzPA The singlet excitation level of the fluorescent material 1,6mMemFLPAPrn is the singlet excitation level of It is greater than the 1,6mMemFLPA triplet excitation level. It is related to the fact that it is lower than the triplet excitation level of Prn, and the fluorescence emission layer (first emission layer 11 3a) shows the regeneration and emission of singlet excitons associated with triplet-triplet anihelization. It is clear that it has a simple configuration.

[0243] Furthermore, the triplet excited state of cgDBCzPA, the host material of the fluorescent layer, is phosphorescent. The first organic compound (2mDBTBPDBq-II) and the second organic compound in the layer ( It can be seen that it is smaller than the triplet excitation level of PCBBiF. In this case, conventionally, many of the triplet excitons generated inside the phosphorescent layer would spread to the fluorescent layer. It disperses and becomes non-radiatively deactivated. However, in the light-emitting element 1 of this embodiment, the first Because the organic compound and the second organic compound form an excited complex, it is generated inside the phosphorescent layer. The triplet excitons do not easily diffuse into the fluorescence-emitting layer. Since the ground state of the excited complex does not exist, One of the contributing factors is thought to be that energy transfer from one excited complex to another is difficult. As a result, the light-emitting element 1 obtains light emission from both the fluorescent light-emitting layer and the phosphorescent light-emitting layer, and It possesses characteristics that defy conventional wisdom, achieving even greater efficiency.

[0244] Thus, the light-emitting element 1, according to one aspect of the present invention, exhibits very well-balanced and excellent characteristics. It can be seen that this is a light-emitting element that can be manufactured simply and inexpensively while possessing the necessary properties. This result indicates that By using an exciplex as the energy donor for the phosphorescent layer, exciton Diffusion was suppressed and non-radiative deactivation of the triplet excitation energy was reduced, and the fluorescence emission layer Luminescence due to delayed fluorescence generation associated with triplet-triplet anhilation in sty materials. Improved efficiency is contributing to this. [Examples]

[0245] In this embodiment, a method for manufacturing light-emitting elements 2 and 3, which are light-emitting elements according to one aspect of the present invention, and The characteristics are shown below. The structural formulas of the organic compounds used in light-emitting elements 2 and 3 are shown below. vinegar.

[0246] [ka]

[0247] (Method for fabricating light-emitting element 2) Indium tin oxide (ITSO) containing silicon dioxide is applied to a glass substrate by sputtering. A 110 nm film was deposited to form the first electrode 101. The electrode area was 2 mm × 2 m². Let's call it m.

[0248] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0249] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate was left for approximately 30 minutes. It was allowed to cool.

[0250] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After applying pressure, the above structural formula (i) is applied to the first electrode 101 by a vapor deposition method using resistance heating. 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophen By co-depositing (abbreviation: DBT3P-II) and molybdenum(VI) oxide, holes An injection layer 111 was formed. Its film thickness was set to 30 nm, and it was made of DBT3P-II and molybdenum oxide. The ratio of ingredients is adjusted to be 2:1 by weight (=DBT3P-II:molybdenum oxide). did.

[0251] Next, on the hole injection layer 111, 9-phenyl-3-[ represented by the above structural formula (ii) 4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviation: PC) A film of zPA was deposited to a thickness of 20 nm to form a hole transport layer 112.

[0252] Furthermore, on the hole transport layer 112, 7-[4-(10-F, represented by the above structural formula (iii)) [phenyl-9-antryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and N,N'-bis(3-methylphen) represented by the above structural formula (iv) (Lu)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl] -Pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) and by weight ratio 1: 10nm so that the result is 0.02 (=cgDBCzPA:1,6mMemFLPAPrn) The first light-emitting layer 113a, which is a fluorescent light-emitting layer, was formed by co-deposition. Subsequently, the above structural formula (v ) represented as 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]di Benzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and the above structural formula ( The expression represented as vi) is N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl -9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene- 2-amine (abbreviation: PCBBiF), represented by the above structural formula (x), is bis{4,6-dimethyl} Lu-2-[5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2 [-pyrazinyl-κN]phenyl-κC}(2,4-pentanedionato-κ 2 O,O') Lydium(III) (abbreviation: [Ir(dmdppr-dmp)2(acac)]) and Weight ratio 0.5:0.5:0.05(=2mDBTBPDBq-II:PCBBiF:[I Co-depositing 5nm so that it becomes r(dmdppr-dmp)2(acac)) is the first glue A light-emitting layer (second light-emitting layer 113b-1) is formed, followed by 2mDBTBPDBq-II PCBBiF and the bis[2-(6-tert-butyl] represented by the above structural formula (viii) -4-pyrimidinyl-κN3)phenyl-κC](2,4-pentanedionato-κ 2 O, O') Iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]) and Weight ratio 0.8:0.2:0.05=(=2mDBTBPDBq-II:PCBBiF:[ Co-deposited at 20 nm so that it becomes Ir(tBuppm)2(acac)), and second phosphorescence A light-emitting layer (second light-emitting layer 113b-2) is formed, and the second light-emitting layer 113 is a phosphorescent light-emitting layer. b was formed.

[0253] Furthermore, in the phosphorescent emitting layer 113b, 2mDBTBPDBq-II and PCBBiF are It forms an excited complex. Furthermore, its emission wavelength is [Ir(dmdppr-dmp)2(a [cac)] and [Ir(tBuppm)2(acac)] overlap with the longest wavelength absorption band. This configuration offers high energy transfer efficiency.

[0254] Furthermore, the host material of the fluorescent emitting layer (first emitting layer 113a) is cgDBCzPA The singlet excitation energy is the same as that of the fluorescent material 1,6mMemFLPAPrn. It is greater than the electromotive force, and the triplet excitation energy of cgDBCzPA is 1,6 It is related to mMemFLPAPrn's triplet excitation energy, and fluorescence The light layer (first light-emitting layer 113a) is associated with singlet excitons in triplet-triplet anihlation. The configuration facilitates regeneration and luminescence.

[0255] Subsequently, a film of 2mDBTBPDBq-II is applied to the second light-emitting layer 113b, which is a phosphorescent light-emitting layer. A film was deposited to a thickness of 10 nm, and further, the bathophenant represented by the above structural formula (ix) was formed. Lorin (abbreviated as BPhen) is deposited to a thickness of 15 nm to form an electron transport layer 114. did.

[0256] After forming the electron transport layer 114, lithium fluoride (LiF) is then applied to a thickness of 1 nm. A layer is deposited to form an electron injection layer 115, and finally, a second electrode 1 that functions as a cathode is formed. As O2, aluminum is deposited to a film thickness of 200 nm, thus in this embodiment A light-emitting element 2 was fabricated.

[0257] In the vapor deposition process described above, resistance heating was used for all deposition steps.

[0258] (Method for fabricating the light-emitting element 3) The light-emitting element 3 has a first phosphorescent light-emitting layer (second light-emitting layer 113b-1) in the light-emitting element 2. The ratio of the constituent substances is 2mDBTBPDBq-II:PCBBiF:[Ir(dmdpp Let r-dmp)2(acac)] = 0.2:0.8:0.05 (weight ratio), and the second phosphorus The ratio of the materials constituting the light-emitting layer (second light-emitting layer 113b-2) is 2mDBTBPDBq- II:PCBBiF:[Ir(tBuppm)2(acac)]=0.9:0.1:0. Except for setting 05 = (weight ratio), it was manufactured in the same way as light-emitting element 2.

[0259] The light-emitting element 2 and light-emitting element 3 are placed in a glove box under a nitrogen atmosphere, and the light-emitting elements are large The process of sealing the element with a glass substrate to prevent exposure to the elements (applying a sealing material around the element, After UV treatment and heat treatment at 80°C for 1 hour during sealing, the characteristics of these light-emitting elements are as follows: The measurements were performed at room temperature (in an atmosphere maintained at 25°C) using an integrating sphere. The current density was 2.5 mA / cm². 3 A table summarizing the characteristic values ​​is shown below.

[0260] [Table 2]

[0261] Despite not having a special light extraction structure in either light-emitting element 2 or light-emitting element 3, It showed good external quantum efficiency and power efficiency. Furthermore, the voltage was 3V, compared to tandem-type light-emitting elements. This is a lower value compared to others.

[0262] Furthermore, the emission spectra of light-emitting element 2 and light-emitting element 3 are shown in Figure 19(A) and (B), respectively. This shows that the red light originating from [Ir(dmdppr-dmp)2(acac)] is found in the emission spectrum. Chromatic emission, green emission derived from [Ir(tBuppm)2(acac)] and 1,6mMem Blue emission originating from FLPAPrn was observed in all cases. From this, it can be concluded that the fluorescence emission layer is Sufficient light can be emitted from either the first light-emitting layer 113a or the second light-emitting layer 113b, which is a phosphorescent light-emitting layer. It can be seen that light emission is being obtained.

[0263] Furthermore, these light-emitting elements also have good color rendering properties, with an average color rendering index Ra of 85 or higher, and du The v is also small, making it suitable for lighting applications. Furthermore, the color temperatures are 4710K (daylight white) and 295K respectively. It exhibits characteristics that match the 0K incandescent color temperature and specifications.

[0264] By the way, the difference between light-emitting element 2 and light-emitting element 3 is the material that makes up the second light-emitting layer 113b It is solely the mixing ratio. In other words, by the simple operation of adjusting the mixing ratio of the constituent substances, 2950 This embodiment also allows for the acquisition of white light emission over a wide color temperature range from K to 4710K. This is shown below. Note that depending on the adjustment, the color temperature may be 2950K or lower, or 4710K or higher. This is also feasible. Furthermore, the fact that this is achieved without a significant decrease in efficiency is a major advantage. This is a key feature. In this embodiment, the light-emitting element was fabricated using three colors of light: blue, green, and red, resulting in white light emission. Although the above example has been explained, if a light-emitting element is made with a different light-emitting color, the components of that light-emitting element will be... By adjusting the mixing ratio of materials, the proportion of mixed colors in the emission can be controlled, allowing for the easy production of desired emission colors. This can be used to obtain a light-emitting element.

[0265] Thus, the light-emitting element 2 and the light-emitting element 3 have very well-balanced and excellent characteristics. This shows that it is a light-emitting element that can be manufactured simply and inexpensively. This result indicates phosphorescence. By using exciplex as the energy donor for the light-emitting layer, exciton diffusion is achieved. The suppression of triplet excitation energy and the reduction of non-radiative deactivation of the triplet excitation energy, and the host material of the fluorescent emission layer Improvement of luminescence efficiency due to delayed fluorescence generation associated with triplet-triplet anhilation in [the system] The top is contributing. [Examples]

[0266] This embodiment describes a method for manufacturing a light-emitting element 4, which is a light-emitting element according to one aspect of the present invention, and its characteristics. As shown, the light-emitting element 4 has the first light-emitting layer 113a on the cathode side and the second light-emitting layer 113b on the anode side. This is the formed light-emitting element. The structural formula of the organic compound used in light-emitting element 4 is shown below.

[0267] [ka]

[0268] (Method for fabricating the light-emitting element 4) Indium tin oxide (ITSO) containing silicon dioxide is applied to a glass substrate by sputtering. A 110 nm film was deposited to form the first electrode 101. The electrode area was 2 mm × 2 m². Let's call it m.

[0269] Next, as a pretreatment for forming light-emitting elements on the substrate, the substrate surface is washed with water, and 200 After firing at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0270] Then, 10 -4 A substrate is introduced into a vacuum deposition apparatus where the internal pressure is reduced to approximately Pa, and then vacuum deposition is performed. After vacuum firing at 170°C for 30 minutes in the heating chamber of the apparatus, the substrate was left for approximately 30 minutes. It was allowed to cool.

[0271] Next, the first electrode 101 is formed such that the surface on which the first electrode 101 is formed faces downwards. The prepared substrate is fixed to a substrate holder provided inside the vacuum deposition apparatus, 10 -4 Reduced to approximately Pa After applying pressure, the above structural formula (i) is applied to the first electrode 101 by a vapor deposition method using resistance heating. 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophen By co-depositing (abbreviation: DBT3P-II) and molybdenum(VI) oxide, holes An injection layer 111 was formed. Its film thickness was set to 40 nm, and it was made of DBT3P-II and molybdenum oxide. The ratio of ingredients is adjusted to be 4:2 by weight (=DBT3P-II:molybdenum oxide). did.

[0272] Next, on the hole injection layer 111, N-(1,1'-Bif, represented by the above structural formula (vi) is injected. (phenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl [Nyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) 2 A hole transport layer 112 was formed by depositing a film with a thickness of 0 nm.

[0273] Furthermore, on the hole transport layer 112, 2-[3'-(dibenzothi represented by the above structural formula (v) is added. Offen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and PCBBiF, represented by the above structural formula (vii) ( Pivaloylmethanato)bis(2,3,5-triphenylpyradinato)iridium(III )(Abbreviation: [Ir(tppr)2(dpm)] and a weight ratio of 0.2:0.8:0.05( =2mDBTBPDBq-II:PCBBiF:[Ir(tppr)2(dpm)]) and To achieve this, a 20nm co-deposit was performed to form the first phosphorescent emitting layer (second emitting layer 113b-1). Next, 2mDBTBPDBq-II and PCBBiF are represented by the above structural formula (viii). Bis[2-(6-tert-butyl-4-pyrimidinyl-κN3)phenyl-κC] (2,4-pentanedionato-κ) 2 O,O') Iridium(III) (Abbreviation: [Ir(t Buppm)2(acac)]) and a weight ratio of 0.3:0.7:0.05 (=2mDBT) BPDBq-II:PCBBiF:[Ir(tBuppm)2(acac)]) A 5nm layer is co-deposited to form a second phosphorescent layer (second phosphorescent layer 113b-2), thereby generating phosphorescence. A second light-emitting layer 113b, which is a light-emitting layer, was formed. Subsequently, the structure represented by the above structural formula (iii) 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c, [g]carbazole (abbreviation: cgDBCzPA) and N,N represented by the above structural formula (iv) '-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorine [Len-9-yl)phenyl]-pyrene-1,6-diamine (abbreviation: 1,6mMemFLP) APrn) and a weight ratio of 1:0.04 (=cgDBCzPA:1,6mMemFLPAP) A first light-emitting layer, 113a, which is a fluorescent light-emitting layer, is formed by co-depositing 25 nm of material so that it becomes rn. A light-emitting layer 113 was formed.

[0274] Furthermore, in the second light-emitting layer 113b, which is a phosphorescent light-emitting layer, 2mDBTBPDBq-I I and PCBBiF form an excited complex. Furthermore, its emission wavelength is [Ir(tppr)2( [dpm)] and [Ir(tBuppm)2(acac)] overlap with the longest wavelength absorption band. This configuration offers high energy transfer efficiency.

[0275] Furthermore, the host material of the fluorescent emitting layer (first emitting layer 113a) is cgDBCzPA The singlet excitation energy is the same as that of the fluorescent material 1,6mMemFLPAPrn. It is greater than the electromotive force, and the triplet excitation energy of cgDBCzPA is 1,6 It is related to mMemFLPAPrn's triplet excitation energy, and fluorescence The light layer (first light-emitting layer 113a) is associated with singlet excitons in triplet-triplet anihlation. The configuration facilitates regeneration and luminescence.

[0276] Subsequently, cgDBCzPA is applied to the first light-emitting layer 113a, which is a fluorescent light-emitting layer, with a film thickness of 10 nm. The film is formed in such a manner, and furthermore, bathophenanthroline (abbreviated) represented by the above structural formula (ix) A film of BPhen was deposited to a thickness of 15 nm to form an electron transport layer 114.

[0277] After forming the electron transport layer 114, lithium fluoride (LiF) is applied to a thickness of 1 nm. A vapor deposition process is carried out to form an electron injection layer 115, and finally, a second electrode 102 is formed to function as a cathode. Then, by depositing aluminum to a film thickness of 200 nm, the light-emitting element of this embodiment is created. We prepared sample 4. In the deposition process described above, resistance heating was used for all deposition steps.

[0278] The element structure of the light-emitting element 4 is shown in the table below.

[0279] The light-emitting element 4 is placed in a glove box under a nitrogen atmosphere, so that the light-emitting element 4 is not exposed to the atmosphere. The process involves sealing the element with a glass substrate (applying a sealing material around the element and using UV light during sealing). After processing (heat treatment at 80°C for 1 hour), the current density of the light-emitting element 4 was 2.5 mA / cm². 2 And, 1000 cd / cm² 2 We measured the characteristics of the surrounding area.

[0280] [Table 3]

[0281] Despite not having a special light extraction structure, the light-emitting element 4 exhibits good external quantum efficiency. It demonstrated power efficiency. Furthermore, the voltage was 2.7V, which is significantly lower compared to tandem-type light-emitting elements. The value is low.

[0282] Furthermore, the emission spectrum of the light-emitting element 4 is shown in Figure 20. From the emission spectrum, [Ir(t Red emission originating from [ppr)2(dpm)] and [Ir(tBuppm)2(acac)] Both green emission from the source and blue emission from 1,6mMemFLPAPrn were observed. From this, the first light-emitting layer 113a, which is a fluorescent light-emitting layer, and the second light-emitting layer, which is a phosphorescent light-emitting layer It can be seen that sufficient light emission is obtained from both sides of the photolayer 113b.

[0283] Furthermore, the light-emitting element 4 also has good color rendering with an average color rendering index Ra of 84, and its duv is small. It is ideal for lighting applications. Furthermore, it exhibits characteristics that conform to the standard, such as a 2690K incandescent color temperature. They are doing it.

[0284] Thus, the light-emitting element 4 has a good balance and excellent characteristics, and can be manufactured simply and inexpensively. This shows that it is a light-emitting element that can do this. This result indicates the energy of the phosphorescent layer. By using exciplex as the exciton generator, exciton diffusion is suppressed, and triplet excitation is suppressed. The non-radiative deactivation of energy was reduced, and the triplet-triplet relationship in the host material of the fluorescent emission layer was reduced. The improvement in luminescence efficiency due to the generation of delayed fluorescence associated with anhilation contributes to this. Furthermore, it was found that good characteristics could be obtained even when the stacking order of the light-emitting layer 113 was changed. [Explanation of Symbols]

[0285] 101 First electrode 102 Second electrode 103 EL layer 111 Hole injection layer 112 Hole transport layer 113 Emitting layer 113a First light-emitting layer 113b Second light-emitting layer 113b-1 Second light-emitting layer 113b-2 Second luminescent layer 114 Electron transport layer 115 Electron injection layer 400 circuit boards 401 First electrode 403 EL layer 404 Second electrode 405 sealant 406 Sealant 407 Sealing substrate 412 pads 420 IC chips 501 First electrode 502 Second electrode 511 First light-emitting unit 512 Second light-emitting unit 513 Charge generation layer 601 Drive circuit section (source line drive circuit) 602 pixel section 603 Drive circuit section (gate wire drive circuit) 604 Sealing substrate 605 Sealant 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 element substrate 611 Switching FET 612 Current-Controlled FET 613 First electrode 614 Insulators 616 EL layer 617 Second electrode 618 Light-emitting element 623 n-channel FET 624 p-channel FET 625 Dry material 901 cabinet 902 Liquid Crystal Layer 903 Backlight Unit 904 cabinet 905 Driver IC 906 terminal 951 circuit board 952 Electrode 953 Insulating layer 954 Partition layer 955 EL layer 956 Electrode 1001 circuit board 1002 Underlying insulating film 1003 Gate Insulator 10:06 Guard Station 1007 🙏 1008 Gate 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 Electrode First electrode of 1024W light-emitting element First electrode of 1024R light-emitting element First electrode of 1024G light-emitting element 1024B First electrode of light-emitting element 1025 Bulkhead 1028 EL layer 1029 Second electrode of light-emitting element 1031 Sealing substrate 1032 Sealant 1033 Transparent base material 1034R Red colored layer 1034G Green colored layer 1034B Blue colored layer 1035 Black Matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 pixel section 1041 Drive circuit section 1042 Peripheral area 2001 cabinet 2002 light source 3001 Lighting device 5000 display area 5001 Display area 5002 Display area 5003 Display area 5004 Display area 5005 Display area 7101 enclosure 7103 Display section 7105 Stand 7107 Display section 7109 Operation Keys 7110 Remote Control Unit 7201 Main Unit 7202 enclosure 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing device 7210 Second display unit 7301 enclosure 7302 enclosure 7303 Connection section 7304 Display section 7305 Display section 7306 Speaker section 7307 Recording media insertion section 7308 LED Lamp 7309 Operation Keys 7310 Connection terminal 7311 Sensor 7401 enclosure 7402 Display section 7403 Operation Buttons 7404 External connection port 7405 Speaker 7406 Microphone 7400 mobile phones 9033 Fastener 9034 Switch 9035 Power switch 9036 Switch 9038 Operation switch 9630 cabinet 9631 Display section 9631a Display section 9631b Display section 9632a Touch panel area 9632b Touch panel area 9633 Solar Cell 9634 Charge / Discharge Control Circuit 9635 Battery 9636 DC-DC converter 9637 Operation Keys 9638 converter 9639 button

Claims

[Claim 1] Between the first electrode and the second electrode, there is a first light-emitting layer and a second light-emitting layer, The first light-emitting layer is provided between the first electrode and the second light-emitting layer. The second light-emitting layer is provided between the first light-emitting layer and the second electrode. The first light-emitting layer comprises a fluorescent light-emitting material and a host material, The second light-emitting layer comprises a material, a first organic compound, and a second organic compound. The first organic compound and the second organic compound are a combination capable of forming an excited complex. The aforementioned material can convert triplet excitation energy into light emission. The emission spectrum from the first light-emitting layer is in a shorter wavelength region than the emission spectrum from the second light-emitting layer.

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