Light-emitting element

Abstract

To provide a novel light-emitting element, to provide a light-emitting element with a long life, and to provide a light-emitting element with an excellent light-emitting efficiency.SOLUTION: In a light-emitting element, an EL layer has a hole injection layer, a first layer, a second layer, a third layer, and a fourth layer. The second layer is located between the first layer and the third layer, the fourth layer is located between the third layer and a second electrode, the hole injection layer has an organic adapter, the first layer has a first hole transfer material, the second layer has a second hole transfer material, the third layer has a third hole transfer material, the fourth layer has a host material and a light-emitting material, the HOMO level of the second hole transfer material is deeper than the HOMO level of the first hole transfer material, the HOMO level of the host material is deeper than the HOMO level of the second hole transfer material, the HOMO level of the third hole transfer material is the same as or deeper than the HOMO level of the host material, and a difference between the HOMO level of the second hole transfer material and the HOMO level of the third hole transfer material is 0.3 eV or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to a light-emitting element, a display module, a lighting module, a display device, a light-emitting element, a display module ... The present invention relates to an optical device, an electronic device, and a lighting device. The technical field of one embodiment of the invention disclosed in the present specification and the like is an object, a method, or a manufacturing method. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacturing method, It is about Cha, or composition of matter. More specifically, the technical field of one embodiment of the present invention disclosed in this specification is a semiconductor device, a display display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, storage devices, imaging devices, and One example is a driving method or a manufacturing method thereof. [Background technology]

[0002] Electroluminescence (EL) using organic compounds The practical application of light-emitting elements (organic electroluminescence (EL) elements) that utilize the luminescence element is progressing. The basic structure of the device is a pair of electrodes sandwiching an organic compound layer (EL layer) containing a light-emitting material. A voltage is applied to this element to inject carriers, and the recombination energy of the carriers is By utilizing this, light can be emitted from the light-emitting material.

[0003] Since such light-emitting elements are self-emitting, when used as display pixels, they are much more efficient than liquid crystal displays. It has the advantage of being highly visible and does not require a backlight, making it suitable for use with flat panel displays. In addition, displays using such light-emitting elements are thin and lightweight. Another major advantage is that it can be fabricated quickly. Another feature is its extremely fast response time. be.

[0004] In addition, since the light-emitting layer of these light-emitting devices can be formed continuously in two dimensions, This can be achieved by using point light sources such as incandescent bulbs and LEDs, or This is a feature that is difficult to obtain with linear light sources such as fluorescent lamps, so it can be used as a surface light source for lighting, etc. It is also highly useful.

[0005] Displays and lighting devices using such light-emitting elements are suitable for use in a variety of electronic devices. However, research and development is ongoing to develop light-emitting devices with better efficiency and life span.

[0006] As a material for the hole injection layer used to facilitate the injection of carriers, particularly holes, into the EL layer, Organic acceptors can be easily formed into films by vapor deposition, making them suitable for mass production. However, the LUMO level of the organic acceptor and the hole transport layer If the HOMO level of the organic compound constituting the EL layer is far from that of the EL layer, it is difficult to inject holes into the EL layer. From this, the LUMO of the organic acceptor and the HO of the organic compound constituting the hole transport layer In order to bring the HOMO levels closer together, the organic compound that constitutes the hole transport layer should have a shallow HOMO level. By using this material, the HOMO level of the host material used in the light-emitting layer and the hole transport layer can be determined. The difference between the HOMO level of the organic compound and that of the EL layer becomes large. Even if holes can be injected, it becomes difficult to inject holes from the hole transport layer into the host material of the light-emitting layer. There was a problem with it getting stuck.

[0007] In Patent Document 1, a first hole injection layer is provided between a first hole transport layer in contact with the hole injection layer and a light emitting layer. Hole transport properties with a HOMO level between the HOMO level of the interlayer and the HOMO level of the host material A configuration for applying the material is disclosed.

[0008] The characteristics of light-emitting devices have improved remarkably, but there are still many issues to be resolved, including efficiency and durability. It must be said that the current level of technology is still insufficient to meet the high level of demands placed on the industry. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2011 / 065136 Brochure Summary of the Invention [Problem to be solved by the invention]

[0010] In view of the above, an object of one embodiment of the present invention is to provide a novel light-emitting element. Another object of the present invention is to provide a light-emitting element having good luminous efficiency. The purpose is to provide

[0011] In another embodiment of the present invention, a light-emitting device, an electronic device, and a display device each having high reliability are provided. Another embodiment of the present invention provides a light-emitting device with low power consumption. The present invention aims to provide a device, an electronic device, and a display device.

[0012] It is sufficient for the present invention to solve any one of the above problems. [Means for solving the problem]

[0013] A light-emitting element according to one embodiment of the present invention includes a first electrode, a second electrode, and an EL layer. The EL layer is located between the first electrode and the second electrode and includes a hole injection layer, a first layer, and a second layer. a hole injection layer between the first electrode and the first layer, a third layer, and a fourth layer; The second layer is located between the first layer and the third layer, and the fourth layer is located between the third layer and the second layer. and a second electrode, the hole injection layer having an organic acceptor and the first layer having a first hole transport the second layer having a second hole transport material, and the third layer having a third hole transport material. The fourth layer has a host material and a light-emitting material, and the HOMO level of the second hole transport material is , the HOMO level of the first hole transporting material is deeper than the HOMO level of the host material, and the HOMO level of the second hole transporting material is deeper than the HOMO level of the first hole transporting material. The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the second hole transport material is the same as or deeper than the HOMO level of the third hole transport material. The difference in HOMO levels of the transport materials is 0.3 eV or less.

[0014] A light-emitting element according to one embodiment of the present invention includes a first electrode, a second electrode, and an EL layer. The EL layer is located between the first electrode and the second electrode and includes a hole injection layer, a first hole transport layer, and a second hole transport layer, a third hole transport layer, and a light emitting layer, and the hole injection layer is an organic acrylic resin. the first hole transport layer having a first hole transport material and the second hole transport layer having a second hole transport material; the third hole transport layer has a third hole transport material, and the light emitting layer has a phosphor a HOMO level of the second hole transport material is lower than that of the first hole transport material; The HOMO level of the host material is deeper than the HOMO level of the second hole transport material. The HOMO level of the third hole transporting material is deeper than that of the host material. The HOMO level of the second hole transport material is the same or deeper than the HOMO level of the third hole transport material. The difference between these values ​​is 0.3 eV or less.

[0015] Another embodiment of the present invention is a light-emitting element having the above structure, in which the organic acceptor is two ,3,6,7,10,11-Hexacyano-1,4,5,8,9,12-hexaazatolyl The light-emitting element is phenylene.

[0016] Another embodiment of the present invention is a light-emitting element having the above structure, The HOMO level of the light-emitting element is -5.4 eV or higher.

[0017] Another embodiment of the present invention is a light-emitting element having the above structure, and the HOMO level of the second hole transport material is 0.3 eV or less. It is an element.

[0018] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: and the HOMO level of the third hole transport material is 0.2 eV or less. It is an element.

[0019] Another embodiment of the present invention is a light-emitting element having the above structure, and the HOMO level of the second hole transport material is 0.2 eV or less. It is an element.

[0020] Another embodiment of the present invention is a light-emitting element having the above structure, in which the HOMO This is a light-emitting device whose HOMO level is higher than the HOMO level of the host material.

[0021] Another embodiment of the present invention is a light-emitting element having the above structure, is a light-emitting element in which a substance having a fluorenylamine skeleton is used.

[0022] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: The light-emitting element is formed of a substance having a triphenylamine skeleton.

[0023] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: In the light-emitting element, the material does not contain amine.

[0024] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: The light-emitting element includes a carbazole skeleton.

[0025] Another embodiment of the present invention is a light-emitting element having the above structure, wherein a carbazole skeleton is A light-emitting element having a phenylcarbazole skeleton.

[0026] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: The light-emitting element includes a triphenylene skeleton.

[0027] Another embodiment of the present invention is a light-emitting element having the above structure, further comprising: The light-emitting element includes a naphthalene skeleton.

[0028] Another embodiment of the present invention is a light-emitting element having the above structure, in which the host material is an ant The light-emitting element includes a helical skeleton.

[0029] Another embodiment of the present invention is a light-emitting element having the above structure, in which the host material is diphenyl The light-emitting element includes a nylanthracene skeleton.

[0030] Another embodiment of the present invention is a light-emitting element having the above structure, in which the host material is a carba compound. The light-emitting device includes a sol skeleton.

[0031] Another embodiment of the present invention is a light-emitting element having the above structure, wherein a carbazole skeleton is The light-emitting element has a benzocarbazole skeleton. Particularly preferably, the carbazole skeleton is a di The light-emitting element has a benzocarbazole skeleton.

[0032] Another embodiment of the present invention is a light-emitting element having the above structure, in which the light-emitting material emits fluorescent light. It is a light-emitting element that is a material.

[0033] Another embodiment of the present invention is a light-emitting element having the above structure, in which the light-emitting material emits light. The light emitted is blue fluorescent light.

[0034] Another embodiment of the present invention is a light-emitting element having the above structure, in which the light-emitting material is a condensed aromatic The light-emitting device is an aromatic diamine compound.

[0035] Another embodiment of the present invention is a light-emitting element having the above structure, in which the light-emitting material is pyrene. The light-emitting device is a diamine compound.

[0036] Another embodiment of the present invention is a light-emitting element having any of the above structures, and a transistor or A light emitting device having a substrate.

[0037] Another embodiment of the present invention is a light-emitting device having the above structure, and a sensor, an operation button, a switch, and a light-emitting element. It is an electronic device having a speaker or a microphone.

[0038] Another embodiment of the present invention is a lighting device including a light-emitting device having the above structure and a housing. It is located.

[0039] In this specification, the term "light-emitting device" includes an image display device using a light-emitting element. In addition, a connector, such as an anisotropic conductive film or TCP (Tape Carrier), is attached to the light emitting element. The module has a printed wiring board attached to the end of the TCP. The module or light emitting element is equipped with a COG (Chip On Glass) method. The module on which the IC (integrated circuit) is directly mounted may have a light emitting device. In addition, lighting fixtures and the like may include a light-emitting device. Effect of the Invention

[0040] According to one embodiment of the present invention, a novel light-emitting element can be provided. Alternatively, a light-emitting element having good luminous efficiency can be provided. do.

[0041] In another embodiment of the present invention, a light-emitting device, an electronic device, and a display device each having high reliability are provided. In another embodiment of the present invention, a light-emitting device with low power consumption can be provided. An electronic device and a display device can each be provided.

[0042] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. Effects other than these may also be included. The above is self-evident from the description, drawings, claims, etc. Other effects can be extracted from the claims and other descriptions. [Brief description of the drawings]

[0043] [Figure 1] Schematic diagram of a light-emitting element. [Diagram 2] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Diagram 3] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Figure 4] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Diagram 5] FIG. 1 is a conceptual diagram of a passive matrix light-emitting device. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] 1 is a diagram illustrating an in-vehicle display device and a lighting device. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] Luminance-current density characteristics of light-emitting element 1. [Figure 15] Current efficiency-luminance characteristics of light-emitting element 1. [Figure 16] Luminance-voltage characteristics of light-emitting element 1. [Figure 17] Current-voltage characteristics of light-emitting element 1. [Figure 18] External quantum efficiency-luminance characteristics of light-emitting element 1. [Figure 19] Emission spectrum of light-emitting element 1. [Figure 20] Normalized luminance vs. time change characteristics of light-emitting element 1. [Figure 21] luminance-current density characteristics of light-emitting element 2 and light-emitting element 3. [Figure 22] Current efficiency-luminance characteristics of Light-emitting element 2 and Light-emitting element 3. [Diagram 23] luminance-voltage characteristics of light-emitting element 2 and light-emitting element 3. [Figure 24] Current-voltage characteristics of the light-emitting element 2 and the light-emitting element 3. [Diagram 25]4 shows external quantum efficiency-luminance characteristics of the light-emitting element 2 and the light-emitting element 3. [Figure 26] 4 shows emission spectra of the light-emitting element 2 and the light-emitting element 3. [Figure 27] Normalized luminance-time change characteristics of the light-emitting element 2 and the light-emitting element 3. [Figure 28] Luminance-current density characteristics of light-emitting element 4. [Figure 29] Current efficiency-luminance characteristics of light-emitting element 4. [Diagram 30] Luminance-voltage characteristics of light-emitting element 4. [Diagram 31] Current-voltage characteristics of light-emitting element 4. [Diagram 32] External quantum efficiency-luminance characteristics of light-emitting element 4. [Diagram 33] Emission spectrum of light-emitting element 4. [Diagram 34] Normalized luminance vs. time change characteristics of light-emitting element 4. [Diagram 35] luminance-current density characteristics of light-emitting element 5; [Diagram 36] Current efficiency-luminance characteristics of light-emitting element 5. [Figure 37] Luminance-voltage characteristics of light-emitting element 5. [Figure 38] Current-voltage characteristics of light-emitting element 5. [Figure 39] External quantum efficiency-luminance characteristics of light-emitting element 5. [Diagram 40] Emission spectrum of light-emitting element 5. [Diagram 41] Normalized luminance vs. time change characteristics of light-emitting element 5. [Diagram 42] 1 shows the luminance-current density characteristics of light-emitting elements 6 to 8. [Diagram 43] 4 shows current efficiency-luminance characteristics of light-emitting elements 6 to 8. [Diagram 44] 4 shows the luminance-voltage characteristics of light-emitting elements 6 to 8. [Diagram 45] 4 shows current-voltage characteristics of light-emitting elements 6 to 8. [Diagram 46] 4 shows external quantum efficiency-luminance characteristics of light-emitting elements 6 to 8. [Figure 47] 4 shows emission spectra of light-emitting elements 6 to 8. [Figure 48] Normalized luminance-time change characteristics of light-emitting elements 6 to 8. [Figure 49] 13 shows the luminance-current density characteristics of light-emitting elements 9 to 11. [Figure 50] 13 shows current efficiency-luminance characteristics of light-emitting elements 9 to 11. [Figure 51] 13 shows the luminance-voltage characteristics of light-emitting elements 9 to 11. [Figure 52] 13 shows current-voltage characteristics of light-emitting elements 9 to 11. [Diagram 53] 13 shows external quantum efficiency-luminance characteristics of light-emitting elements 9 to 11. [Figure 54] 4 shows emission spectra of light-emitting elements 9 to 11. [Figure 55] Normalized luminance-time change characteristics of light-emitting elements 9 to 11. [Figure 56] luminance-current density characteristics of light-emitting element 12; [Figure 57] Current efficiency-luminance characteristics of the light-emitting element 12. [Figure 58] Luminance-voltage characteristics of the light-emitting element 12. [Figure 59] Current-voltage characteristics of the light-emitting element 12. [Figure 60] External quantum efficiency-luminance characteristics of the light-emitting element 12. [Figure 61] The emission spectrum of the light-emitting element 12. [Figure 62] Normalized luminance-time change characteristics of the light-emitting element 12. [Figure 63] 1H-NMR chart of BBAβNB. [Figure 64] 1H-NMR chart of βNP2PC. [Figure 65] 1H-NMR chart of BBAαNB. [Figure 66] 1H-NMR chart of BBAβNBi. [Figure 67] 1H-NMR chart of βNPβNC. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the form and details are not limited thereto without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that various modifications may be made. It should not be construed as being limited to the description of the embodiment modes.

[0045] (Embodiment 1) FIG. 1A illustrates a light-emitting element according to one embodiment of the present invention. The device has a first electrode 101, a second electrode 102, and an EL layer 103. From the electrode 101 side, a hole injection layer 111, a first hole transport layer 112-1, a second hole transport layer 11 2-2, a third hole transport layer 112-3, and a light emitting layer 113. Also, an electron transport layer 114 and an electron injection layer 115 may be provided.

[0046] In the light-emitting element of one embodiment of the present invention, the light-emitting layer 113 contains a host material and a light-emitting material. The injection layer 111 is an organic acceptor, the first hole transport layer 112-1 is an organic hole transport layer 11 The second hole transport layer 112-2 and the third hole transport layer 112-3 are made of a first hole transport material, a second hole transport material, and a third hole transport material.

[0047] In addition, the HOMO level of the host material is deeper than the HOMO level of the second hole transport material. The HOMO level of the second hole transporting material is lower than the HOMO level of the first hole transporting material. The HOMO level of the third hole transport material is located deeper than that of the host material. The HOMO level of the second hole transport material is the same as or deeper than the OMO level of the second hole transport material. The difference between the HOMO level of the first hole transport material and the HOMO level of the third hole transport material is 0.3 eV or less.

[0048] The organic acceptor is an organic compound with a deep LUMO level. Charge separation occurs between the LUMO level and other organic compounds whose HOMO level values ​​are close to each other. By this, holes can be generated in the organic compound. In the light-emitting device of this embodiment, holes are generated in the first hole transport material that is in contact with the organic acceptor. The acceptor is a compound having an electron-withdrawing group (halogen or cyano group), e.g., 7,7, 8,8-Tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-T CNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, Chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12- It is recommended to use hexaazatriphenylene (HAT-CN). This is preferred because it has high acceptability and stable film quality.

[0049] The difference between the LUMO level of the organic acceptor and the HOMO level of the first hole transport material is Since it depends on the acceptor strength of the puta, there is no particular limit, but it is generally based on the difference in the level If the charge is less than 1 eV, holes can be injected. When used as a LUMO level of HAT-CN, the LUMO level was determined from cyclic voltammetry measurements. The HOMO level of the first hole transport material is estimated to be -4.41 eV, so the HOMO level of the first hole transport material is -5.4 e However, it is preferable that the HOMO level of the first hole transport material is not too high. If the thickness becomes too large, the hole injection property to the second hole transport material becomes poor. Since the work function of such an anode is around -5 eV, the first positive electrode has a higher HOMO level than that. The use of a hole transport material is disadvantageous. Therefore, the HOMO level of the first hole transport material is preferably −5.0 eV or less.

[0050] The holes generated in the first hole transport material are moved toward the second electrode 102 by the electric field, and The second hole transport layer 112-2 is injected into the second hole transport layer 112-2. The HOMO level of the hole transporting material is the same as the HOMO level of the first hole transporting material and the H Since the first hole transport layer 112-1 is located between the OMO level and the second hole transport layer 112-2, the second hole transport layer 112-3 is easily transported from the first hole transport layer 112-1 to the second hole transport layer 112-2. The first hole transport material and the second hole transport material can inject holes into the transport layer 112-2. The difference in the HOMO levels of the hole transporting material is 0.3 eV or less to smoothly inject holes. It is preferable that the difference is 0.2 eV or less in order to easily inject holes. It is more preferable that

[0051] The holes injected into the second hole transport layer 112-2 are further transported to the second electrode 102 by the electric field. and is injected into the third hole transport layer 112-3. The third hole transport material has a HOMO level equal to that of the host material. The HOMO level of the first hole transport material is the same as or deeper than the HOMO level of the second hole transport material, and the difference between the HOMO level of the first hole transport material and the HOMO level of the second hole transport material is less than 0.35 eV (effective The HOMO level of the second hole transport material and the HOMO level of the third hole transport material are Since the difference between the HOMO level of the hole transport material and the HOMO level of the second hole transport layer 11 is 0.3 eV or less, The injection of holes from the second hole transport layer 112-2 to the third hole transport layer 112-3 is carried out smoothly. In order to inject holes more smoothly, the HOMO level of the third hole transport material and the HOMO level of the second hole transport material are adjusted. The difference between the HOMO level of the transport material is less than 0.25 eV (0.2 eV or less in one significant digit). It is preferable that

[0052] The HOMO level of the third hole transporting material is the same as or deeper than the HOMO level of the host material, There is no barrier for holes to be injected from the third hole transport layer 112-3 to the light emitting layer 113. Since the HOMO level of the hole transport material is equal to or deeper than the HOMO level of the host material, Holes are not only directly injected into the light-emitting material, but also more easily injected directly into the host material. When holes preferentially enter the light-emitting material, it becomes extremely difficult for the holes to move forward in the light-emitting layer, and the light-emitting region becomes The electrons are largely localized at the hole transport layer / light emitting layer interface, which adversely affects the device life. However, as in one embodiment of the present invention, holes can also enter the host material, and the holes can be emitted. In the optical layer, the host is the main source of conduction, but the hole trapping effect of the emitting material is moderate. Therefore, the light-emitting area can be expanded appropriately, resulting in high efficiency and long life. The term "diffuses gradually" means that holes are transported to some extent within the light-emitting layer, but do not penetrate through it. For this reason, it is preferable that the host material has a hole transporting property. Specifically, it is preferable that the host has an anthracene skeleton or a carbazole skeleton. Since it is preferable that the material also has an electron transport property, an anthracene skeleton is particularly suitable. That is, the host material further has an anthracene skeleton and a carbazole skeleton at the same time. The carbazole skeleton is preferably a benzocarbazole skeleton or a dibenzocarbazole skeleton. These structures have a HOMO of 0.1 compared to carbazole. The electron energy becomes about 1.5 eV higher, making it easier for holes to enter (which leads to the widening of the appropriate emission region mentioned above). This is because the third hole transport layer 112-3 is easily formed. The inclusion of such a structure is one of the characteristics of the light-emitting element of one embodiment of the present invention.

[0053] When the HOMO level of the light-emitting material is shallower than that of the host material, When holes are injected into the light-emitting layer from a hole-transporting material that has a shallower HOMO level than the Holes are preferentially injected into the light-emitting material rather than into the insulating material. When holes are injected into the material, they are trapped. If the flow is stagnant, charge accumulation and concentration of recombination areas can accelerate deterioration of the light-emitting layer and reduce light emission. This causes inconveniences such as reduced efficiency.

[0054] On the other hand, the light-emitting device according to the present embodiment has a third hole transport layer 112-3, and the HOM In a light-emitting device having a structure in which the O level is the same as or deeper than the HOMO level of the host material, holes First, holes are preferentially injected into the host material rather than the light-emitting material, which blocks the flow of holes. The holes are trapped in the light-emitting material without being trapped in the light-emitting material, and the recombination area is also dispersed. This provides various advantages, such as improved reliability and improved luminous efficiency.

[0055] Next, examples of the detailed structure and materials of the light-emitting element of one embodiment of the present invention will be described. As described above, the optical element has a pair of electrodes, a first electrode 101 and a second electrode 102, and a plurality of layers between the pair of electrodes. The EL layer 103 is formed of at least the first electrode 101 side, A hole injection layer 111, a first hole transport layer 112-1, a second hole transport layer 112-2, a third hole transport layer 112-3, a It includes a hole transport layer 112-3 and an emissive layer 113.

[0056] The layers other than the EL layer 103 are not particularly limited, and may be a hole injection layer, a hole transport layer, etc. Various layer structures such as a charge generating layer, an electron injection layer, a carrier blocking layer, an exciton blocking layer, etc. The structure can be applied.

[0057] The first electrode 101 is made of a metal, an alloy, or a conductive material having a large work function (specifically, 4.0 eV or more). It is preferable to form the film using a compound such as a carboxylic acid or a mixture thereof. For example, indium tin oxide (ITO), silicon Indium oxide-tin oxide and indium oxide-zinc oxide containing silicon oxide or silicon oxide , indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. These conductive metal oxide films are usually formed by sputtering, but they can also be formed by sol-gel deposition. An example of the method for producing the indium oxide-oxide film is the indium oxide-oxide film. Zinc was sintered using a target containing 1 to 20 wt% zinc oxide in indium oxide. Also, tungsten oxide and zinc oxide are used. Indium oxide (IWZO) contains 0.5% tungsten oxide relative to indium oxide. Sputtering was performed using a target containing 5-5wt% of ZnO and 0.1-1wt% of Zinc Oxide. It can also be formed by the method. In addition, gold (Au), platinum (Pt), nickel (Ni) , Tungsten (W), Chromium (Cr), Molybdenum (Mo), Iron (Fe), Cobalt ( Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride Graphene can also be used. By using this in the layer 103 that is in contact with the first electrode 101, the electric field can be reduced regardless of the work function. You will be able to choose the pole material.

[0058] In this embodiment, the laminated structure of the EL layer 103 is as shown in FIG. Injection layer 111, first hole transport layer 112-1, second hole transport layer 112-2, third hole In addition to the transport layer 112-3 and the light-emitting layer 113, the device has an electron transport layer 114 and an electron injection layer 115. As shown in FIG. 1B, the hole injection layer 111, the first hole transport layer 112- 1, the second hole transport layer 112-2, the third hole transport layer 112-3, and the light emitting layer 113. 2. The structure includes an electron transport layer 114, an electron injection layer 115, and a charge generation layer 116. The materials constituting each layer are specifically shown below.

[0059] The hole injection layer 111 is a layer containing an organic acceptor. Compounds having halogen groups (halogen groups or cyano groups) can be used, and 7,7,8,8-tetramethylphenyl tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-Difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, Chloranil , 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaaza Triphenylene (HAT-CN) and the like can be used as organic acceptors. Compounds such as AT-CN in which an electron-withdrawing group is bonded to a condensed aromatic ring containing multiple heteroatoms. However, it is preferable because it is thermally stable. The organic acceptor is an organic hole transport layer (or a hole At least electrons can be extracted from the material (transport material) by application of an electric field.

[0060] By forming the hole injection layer 111, the hole injection property is improved, and the driving voltage is small. In addition, the organic acceptor can be easily vapor-deposited and formed into a film. Therefore, it is an easy-to-use material.

[0061] The hole transport layer includes a first hole transport layer 112-1, a second hole transport layer 112-2 and a third hole transport layer. The first hole transport layer 112-1 to the third hole transport layer 112-3 are The first hole transport layer 112 contains a hole transport material having hole transport properties. -1 is a first hole transport material, the second hole transport layer 112-2 is a second hole transport material, The third hole transport layer 112-3 contains a third hole transport material. 1×10 -6 cm 2 It is preferable that the hole mobility is 1 / Vs or more. Between each material, the HOMO level of the second hole transport material is lower than the HOMO level of the first hole transport material. The HOMO level of the host material contained in the light-emitting layer 113 is deeper than the O level, and the HOMO level of the host material is the second hole transport The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the second hole transport material is equal to or deeper than the HOMO level of the third hole transport material. The difference in the HOMO levels is less than 0.3 eV. The difference between the HOMO level of the third hole transport material and the HOMO level of the third hole transport material is preferably 0.2 eV or less. I wish.

[0062] As the first hole transport material, it is preferable to use a hole transport material having a relatively shallow HOMO level. Preferably, such an organic compound is a triarylamine and a fluorenyl Substances having an amine backbone are preferred.

[0063] As the third hole transport material, it is preferable to use a hole transport material having a relatively deep HOMO level. Since organic compounds containing amines tend to have shallow HOMO levels, As such a hole transport material, carbazole is preferable. A hole transport material having a carbazole skeleton and a triphenylene skeleton is preferred. Preferably, organic compounds containing a carbazole skeleton and a naphthalene skeleton are used. can be done.

[0064] The second hole transport material may be a hole transport material having a HOMO between the first hole transport material and the third hole transport material. A hole transport material having a level is preferred. Specifically, it is a triarylamine and has a triaryl group. The hole transport material preferably contains a triphenylamine skeleton. It is preferred that the phenyl group in the skeleton is not condensed with a ring.

[0065] The light-emitting layer 113 is a layer containing a host material and a light-emitting material. The light-emitting material is a fluorescent material. Whether it is a material that emits light, a phosphorescent material, or a material that exhibits thermally activated delayed fluorescence (TADF), Either one may be used. In addition, it may be a single layer or a multi-layer structure containing different light-emitting materials. Note that in one embodiment of the present invention, the light-emitting layer 113 may be a layer that exhibits fluorescent light, particularly This is particularly suitable for use in the case of a layer that emits blue fluorescent light.

[0066] In the light-emitting layer 113, examples of materials that can be used as the fluorescent material include the following: Examples include the following: Other fluorescent materials can also be used.

[0067] 5,6-Bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine PAP2BPy, 5,6-bis[4'-(10-phenyl-9-anthracene 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 4'-(10-phenyl-9-anthryl)-4'-(10-phenyl-9-benzol-9-yl)triphenylamine (Abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl Phenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-di Phenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazo Perylene, 2,5,8,11-tetra-tert-butylamine (abbreviation: PCAPA), t-Butylperylene (TBP), 4-(10-phenyl-9-anthryl)-4' -(9-phenyl-9H-carbazol-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-carbazol-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]chloride Cen-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- yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation 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-Bi S(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl) Phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA) Coumarin 54 5T, N,N'-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12- Bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: B PT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl -4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl Chil-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoli 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[i j]Quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanidine DCJTI, 2-{2-tert-butyl-6-[2-(1,1,7,7 -Tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolidine 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) In particular, pyrene diamines such as 1,6FLPAPrn and 1,6mMemFLPAPrn Condensed aromatic diamine compounds, such as fluorine compounds, have high hole trapping properties and high luminous efficiency. This is preferred because it has excellent reliability.

[0068] In the light-emitting layer 113, examples of materials that can be used as phosphorescent materials include Some examples include the following:

[0069] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H -1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III ) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl Nyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mpt z)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H -1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrtz-3 b) Organometallic iridium complexes having a 4H-triazole skeleton, such as tris [3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-trimethyl [Ir(Mptz1-mp)3], tris(1 -Methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium (III) (abbreviation: [Ir(Prptz1-Me)3]) Organometallic iridium complexes with fac-tris[(1-2,6-diisopropyl phenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir (iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimide Dazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmp and organometallic iridium complexes having an imidazole skeleton, such as impt-Me3). Bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium( III) Tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4' ,6'-Difluorophenyl)pyridinato-N,C 2’ ]Iridium(III) picolina Fluorocarbon (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)fluorene} Phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir( CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyri Zinat-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIraca c) Organometallic iridates having phenylpyridine derivatives as ligands having electron-withdrawing groups such as These are compounds that exhibit blue phosphorescence, with wavelengths ranging from 440 nm to It is a compound that has an emission peak at 520 nm.

[0070] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)yl Ir(tBuppm)3, diacetylacetonate (6-Methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mp pm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4- Phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(ac ac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpiperidinyl [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenyl [Pyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)] ), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(II I) (abbreviation: [Ir(dppm)2(acac)]) Metal-iridium complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenyl Rupyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac) ]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyridine Dinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]) Organometallic iridium complexes with pyrazine skeletons such as tris(2-phenylpyridinium) Nat-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2- Phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium (I II) Acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(beta Tris[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]) (2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq) 3]), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylated A compound with a pyridine skeleton, such as setonate (abbreviation: [Ir(pq)2(acac)]) In addition to the organometallic iridium complexes, tris(acetylacetonato)(monophenanthroline)tetraacetate Rare earth metals such as rubium(III) (abbreviation: [Tb(acac)3(Phen)]) These are mainly compounds that exhibit green phosphorescence and have wavelengths between 500 nm and 6 The emission peak is at 100 nm. The body is particularly preferred because it is remarkably excellent in reliability and luminous efficiency.

[0071] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinyl] Nat[Iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis [4,6-Bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)irid Ir(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di( Naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) iridium complexes of the genus acetylacetonato, bis(2,3,5-triphenylpyrazine) Iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2, 3,5-Triphenylpyrazinato)(dipivaloylmethanato)iridium(III)(abbreviation Name: [Ir(tppr)2(dpm])]), (acetylacetonato)bis[2,3-bis [Ir(F Organometallic iridium complexes having a pyrazine skeleton, such as Tris(1-phenylisoquinolinato-N,C 2’ ) Iridium (III) (abbreviation: [I r(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ ) Iridium (I II) Pyridine such as acetylacetonate (abbreviation: [Ir(piq)2(acac)]) In addition to organometallic iridium complexes with diamine structures, 2,3,7,8,12,13,17,1 8-Octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP) Platinum complexes such as tris(1,3-diphenyl-1,3-propanedione)(monofumab) [Eu(DBM)3(Phen)] , Tris[1-(2-thenoyl)-3,3,3-trifluoroacetonate](Monofena [Eu(TTA)3(Phen)] These are compounds that exhibit red phosphorescence and have a 6 It has an emission peak at 00 nm to 700 nm. It is also an organometallic compound with a pyrazine skeleton. The iridium complex can emit red light with good chromaticity.

[0072] In addition to the phosphorescent compounds described above, known phosphorescent light-emitting materials may be selected and used. stomach.

[0073] TADF materials include fullerene and its derivatives, acridine derivatives such as proflavine, Eosin, etc. can be used. Magnesium (Mg), zinc (Zn), cadmium (Cd) Cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium ( Metal-containing porphyrins including, for example, the following: The protoporphyrin-tin fluoride complex (SnF2(Proto IX)) shown in the structural formula )), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin Hemato-Tin Fluoride Complex (SnF2(Hemato IX)), Coproporphyrinte tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), Octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin -Tin fluoride complex (SnF2(Etio I)), octaethylporphyrin-platinum chloride Complexes such as PtCl2OEP are also included.

[0074] [ka]

[0075] In addition, 2-biphenyl-4,6-bis(12-phenylindole) represented by the following structural formula is [2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC- TRZ) and 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'- Phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 9-[ 4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-f Phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzPTzn), 2-[ 4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3 ,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-di Hydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triphenyl PPZ-3TPT, 3-(9,9-dimethyl-9H-acridine-10 -yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9- Dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DP S) 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene π-electron rich heteroaromatic rings such as π-10'-an (abbreviation: ACRSA) and π-electron deficient heteroaromatic rings Heterocyclic compounds having both a heteroaromatic ring and a heterocyclic ring can also be used. The compound has electron-rich and π-deficient heteroaromatic rings, which allows it to transport electrons and holes. In addition, the π-electron rich heteroaromatic ring and the π-electron deficient heteroaromatic ring are preferably The directly bonded materials have the donor properties of the π-electron rich heteroaromatic ring and the aryl properties of the π-electron deficient heteroaromatic ring. The acceptor properties become stronger and the energy difference between the S1 and T1 levels becomes smaller, so the thermal activity It is particularly preferred since it is possible to efficiently obtain deactivated delayed fluorescence. Alternatively, an aromatic ring having an electron-withdrawing group such as a cyano group attached thereto may be used.

[0076] [ka]

[0077] As the host material for the light-emitting layer, various materials such as a material having an electron transport property and a material having a hole transport property can be used. A variety of carrier transport materials can be used.

[0078] As a material having hole transport properties, 4,4'-bis[N-(1-naphthyl)-N-phenylene N,N'-bis(3-methylphenyl)-N, N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenyla 4-phenyl-4'-(9-phenylfluorene) -9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9- mBPAFLP, 4-Fu phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine ( Abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9-H-carbazone PCBBi1BP, 4-(1-naphthyl)triphenylamine butyl)-4'-(9-phenyl-9H-carbazol-3-yl)-triphenylamine PCBANB, 4,4'-di(1-naphthyl)-4''-(9-phenyl- 9H-Carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9- Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl) phenyl]-fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4- (9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-biphenyl Compounds with aromatic amine skeletons such as PCBASF (PCBASF) , 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)benzene Rubazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl) )-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9 Compounds with a carbazole skeleton, such as PCCP (H-carbazole) (abbreviation: PCCP), and 4, 4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation :DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoro (9-phenyl)dibenzothiophene (abbreviation: DBTFLP-III), 4- [4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldiphenyl Compounds with a thiophene skeleton, such as dithiophene (abbreviation: DBTFLP-IV), and 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 Among the above, compounds having an aromatic amine skeleton and Compounds having a carbazole skeleton have good reliability and high hole transport properties. This is also preferable since it contributes to reducing the dynamic voltage.

[0079] As an example of a material having electron transport properties, bis(10-hydroxybenzo[h]quinoli Nat)beryllium(II)(abbreviation:BeBq2), bis(2-methyl-8-quinolinolato )(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), bis(8- Quinolinolato)zinc(II)(abbreviation:Znq), bis[2-(2-benzoxazolyl) phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl) Metal complexes such as phenolato zinc(II) (abbreviation: ZnBTZ) and 2-(4-biphenyl (aryl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation : PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl) phenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butyl) rt-Butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl) phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5 -benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TP BI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H -benzimidazole (abbreviation: mDBTBIm-II) and other polyazole skeletons Heterocyclic compounds and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f ,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothio 2-phenyl-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl 2mCzBPDBq, 4,6 -Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPn P2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation Heterocyclic compounds with diazine skeletons such as 3,5 -Bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCz PPy), 1,3,5-tri[3-(3-pyridyl)-phenyl]benzene (abbreviation: Tm Among the above, heterocyclic compounds having a pyridine skeleton such as diphenyl ether (PyPB) are also suitable. Heterocyclic compounds with an azine skeleton and heterocyclic compounds with a pyridine skeleton have good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton are preferred. It has high electron transport properties and contributes to reducing the driving voltage.

[0080] When a fluorescent substance is used as a light-emitting material, the host material is a material having an anthracene skeleton. A material having an anthracene skeleton is preferably used as a host material for a fluorescent material. When used in the form of an anthraquinone, it is possible to realize a light-emitting layer having excellent light-emitting efficiency and durability. Since many materials having a Cene skeleton have a deep HOMO level, one embodiment of the present invention is preferably applied to The host material may be a dianthracene skeleton material. Substances with a phenylanthracene skeleton, especially a 9,10-diphenylanthracene skeleton, It is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, This is preferable because it enhances the hole injection and transport properties, but the benzene ring is further condensed to the carbazole. When the benzocarbazole skeleton is included, the HOMO is about 0.1 eV higher than that of carbazole. In particular, the host material is preferably dibenzocarbazo When the carbazole skeleton is included, the HOMO is about 0.1 eV higher than that of carbazole, and holes can enter. This is preferable because it is easy to form the hole transport layer, has excellent hole transport properties, and has high heat resistance. Further, preferred host materials include those having a 9,10-diphenylanthracene skeleton and Carbazole skeleton (or benzocarbazole skeleton or dibenzocarbazole skeleton) From the viewpoint of the hole injection and transport properties, the carbazole skeleton is Alternatively, a benzofluorene skeleton or a dibenzofluorene skeleton may be used. An example of a substance is 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl] 3-[4-(1-naphthyl)-phenyl]-9H-carbazole (abbreviation: PCzPA), PCPN, 9-[4-(10-phenyl 7-(9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), [4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazide DBZOL (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthoxy) 2mBnfPPA ), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-biphenyl phenyl-4'-yl}-anthracene (abbreviation: FLPPA). PA, cgDBCzPA, 2mBnfPPA, and PCzPA show very good properties. , is the preferred choice.

[0081] Note that the light-emitting element of one embodiment of the present invention is particularly applicable to a light-emitting element that emits blue fluorescent light. is preferred.

[0082] The host material may be a mixture of a plurality of substances. When used, a material having an electron transporting property and a material having a hole transporting property may be mixed. It is preferable to mix a material having an electron transporting property with a material having a hole transporting property. In this way, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The ratio of the content of the material having a hole transporting property to the content of the material having an electron transporting property is The ratio of the material having electron transport properties to the material having electron transport properties may be 1:9 to 9:1.

[0083] In addition, these mixed materials may form an exciplex. The exciplex is a light-emitting material. The luminescence of the exciplex is such that it overlaps with the wavelength of the lowest energy absorption band of the By selecting such a combination, energy transfer becomes smooth and light emission can be obtained efficiently. This is also preferable since the driving voltage is reduced.

[0084] The electron transport layer 114 is a layer containing a substance having an electron transport property. The above-mentioned substances having an electron transporting property that can be used as the host material are can be used.

[0085] Between the electron transport layer 114 and the second electrode 102, a lithium fluoride layer is formed as an electron injection layer 115. LiF, CsF, CaF2, etc. An alkali metal, an alkaline earth metal or a compound thereof may be provided. The layer is made of a material containing an alkali metal or an alkaline earth metal or a compound thereof. As the electride, for example, calcium carbonate may be used. Examples include a material in which a high concentration of electrons are added to a mixed oxide of titanium and aluminum.

[0086] In addition, a charge generating layer 116 may be provided instead of the electron injection layer 115 (FIG. 1(B)). When a potential is applied to the charge generating layer 116, holes are generated in the layer in contact with the cathode side of the layer, and electrons are generated in the layer in contact with the anode side of the layer. The charge generating layer 116 is a layer that can inject electrons into the layer adjacent to the charge generating layer. At least a P-type layer 117 is included. The P-type layer 117 constitutes the hole injection layer 111 described above. It is preferable to form the P-type layer 1 using the composite material mentioned above as a material that can be used. 17 is a film containing the above-mentioned acceptor material and a hole transport material as a material constituting a composite material. By applying a potential to the P-type layer 117, Electrons are injected into the transport layer 114 and holes are injected into the second electrode 102, which is the cathode, and the light-emitting element operates. do.

[0087] In addition to the P-type layer 117, the charge generating layer 116 also includes an electron relay layer 118 and an electron injection buffer layer 119. Preferably, one or both of layers 119 are provided.

[0088] The electron relay layer 118 contains at least a substance having an electron transport property, and the electron injection buffer layer 1 The function of the junction is to prevent the interaction between the P-type layer 117 and the P-type layer 119 and to transfer electrons smoothly. The LUMO level of the substance having electron transport properties contained in the relay layer 118 is The LUMO level of the acceptor in the electron transport layer 114 and the charge generation layer 116 It is preferable that the LUMO level of the electron-relay layer 11 is between the LUMO level of the material contained in the adjacent layer. Specific energy levels of the LUMO levels of the electron transporting materials used in 8 is set to -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. The electron-transporting material used in the electron relay layer 118 is a phthalocyanine-based It is preferred to use materials or metal complexes having metal-oxygen bonds and aromatic ligands.

[0089] The electron injection buffer layer 119 may include an element selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, and These compounds (alkali metal compounds (oxides such as lithium oxide, halides, lithium carbonate, etc.) (including carbonates such as tium and cesium carbonate), alkaline earth metal compounds (oxides, halogens, etc.) compounds of rare earth metals (including oxides, halides, carbonates) or compounds of rare earth metals (including oxides, halides, carbonates) It is possible to use a material with high electron injection properties such as fluorine.

[0090] The electron injection buffer layer 119 is formed by containing a substance having an electron transporting property and a donor substance. In the case where the donor material is an alkali metal, an alkaline earth metal, or a rare earth metal, and their compounds (alkali metal compounds (oxides such as lithium oxide, halides , including carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (oxides, compounds of rare earth metals (including oxides, halides, carbonates, etc.) In addition to tetrathianaphthalene (TTN), nickelocene, decamethine, An organic compound such as nickelocene can also be used. The electron transport layer 114 is preferably formed of the same material as that of the electron transport layer 114 described above. This can be done.

[0091] The material for forming the second electrode 102 is preferably one having a small work function (specifically, 3.8 eV or less). Bottom) Metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs). Lithium metals, as well as magnesium (Mg), calcium (Ca), strontium (Sr), etc. Elements belonging to Group 1 or 2 of the Periodic Table of the Elements and alloys containing these elements (MgAg, Rare earth metals such as AlLi), europium (Eu), ytterbium (Yb) and the like However, when the second electrode 102 and the electron transport layer are provided with By providing an electron injection layer, the material can be used in a variety of applications, regardless of the magnitude of the work function. Various conductive materials such as indium oxide-tin oxide containing silicon oxide or silicon oxide are used as the second It can be used as the electrode 102. These conductive materials can be applied by dry methods such as vacuum deposition and sputtering, inkjet printing, It is possible to form the film by using a spin coating method, etc. Also, it is possible to form the film by using a wet sol-gel method. Alternatively, the metal material may be used in a wet process to form the metal layer.

[0092] The EL layer 103 can be formed by a variety of methods, including dry and wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, etc. A printing method, an ink jet method, a spin coating method or the like may also be used.

[0093] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0094] The structure of the layers provided between the first electrode 101 and the second electrode 102 is the same as that described above. However, the light emitting region and the metal used in the electrode or carrier injection layer are not limited to the above. The first electrode 101 and the second electrode 102 are arranged so as to suppress quenching caused by the It is preferable to provide a light-emitting region where holes and electrons recombine at a location away from 02.

[0095] In addition, recombination in the hole transport layer or electron transport layer in contact with the light emitting layer 113, particularly in the light emitting layer 113 The carrier transport layer close to the region suppresses the energy transfer from excitons generated in the light-emitting layer. Therefore, the band gap is determined by the luminescent material constituting the luminescent layer or the luminescent material contained in the luminescent layer. It is preferable that the material is made of a substance having a larger band gap than the material. I wish.

[0096] Next, we developed a light-emitting device having a structure in which multiple light-emitting units are stacked (a stacked type device, a tandem type device, etc.). The embodiment of the light-emitting device (also referred to as a "light-emitting device") will be described with reference to FIG. 1(C). A light-emitting element having a plurality of light-emitting units between the light-emitting element and the light-emitting device. 1C). The device is a light-emitting element having a plurality of light-emitting units, and is the light-emitting element shown in FIG. 1(A) or FIG. 1(B). An optical element can be said to be a light-emitting element having one light-emitting unit.

[0097] In FIG. 1C, a first light-emitting unit is disposed between a first electrode 501 and a second electrode 502. The first light-emitting unit 511 and the second light-emitting unit 512 are stacked. A charge generating layer 513 is provided between the first electrode 5 and the second light-emitting unit 512. 1A and the second electrode 502 correspond to the first electrode 101 and the second electrode 102 in FIG. 02, and the same as that described in the explanation of FIG. 1(A) can be applied. The first light emitting unit 511 and the second light emitting unit 512 may have the same configuration or different configurations. It may be composed of

[0098] When a voltage is applied between the first electrode 501 and the second electrode 502, the charge generating layer 513 generates a It has the function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit. That is, in FIG. 1C, the potential of the first electrode is higher than the potential of the second electrode. When a voltage is applied so that the charge generating layer 513 emits electrons to the first light-emitting unit 511, It is sufficient that the second light-emitting unit 512 injects holes into the first light-emitting unit 512.

[0099] The charge generation layer 513 is formed to have the same structure as the charge generation layer 116 described in FIG. The composite material of an organic compound and a metal oxide has the following advantages: Since the light-emitting unit has excellent characteristics, it can be driven at low voltage and low current. When the anode side surface of the charge generating layer 513 contacts the charge generating layer 513, the charge generating layer 513 becomes the light emitting unit. Since the EL element can also function as a hole injection layer for the light-emitting unit, the light-emitting unit does not need to have a hole injection layer. Both are good.

[0100] In addition, when the electron injection buffer layer 119 is provided, the electron injection buffer layer 119 is disposed on the anode side. Since it plays the role of an electron injection layer in the light-emitting unit of the anode side, There is no need to form an electron injection layer.

[0101] Although the light emitting element having two light emitting units has been described in FIG. 1C, a light emitting element having three or more light emitting units may be used. The present invention can be similarly applied to a light-emitting element in which light-emitting units are stacked. In the case of the light-emitting element according to the embodiment of the present invention, a plurality of light-emitting units are disposed between a pair of electrodes, and a charge generating layer 513 is disposed between the pair of electrodes. By separating the layers, it is possible to achieve high brightness light emission while keeping the current density low. It is possible to realize a long-life element. It is also possible to realize a light-emitting device that can be driven at a low voltage and consumes low power. It is possible.

[0102] In addition, by making the emission color of each light-emitting unit different, For example, a light-emitting element having two light-emitting units can be In this case, the first light-emitting unit emits red and green light, and the second light-emitting unit emits blue light. In this way, it is possible to obtain a light-emitting element that emits white light as a whole.

[0103] The above configuration may be appropriately combined with other embodiments or other configurations in this embodiment. is possible.

[0104] (Embodiment 2) In this embodiment mode, a light-emitting device using the light-emitting element described in Embodiment 1 will be described.

[0105] In this embodiment, a light-emitting device manufactured using the light-emitting element described in Embodiment 1 will be described. The description will be given with reference to FIG. 2. FIG. 2(A) is a top view showing a light-emitting device, and FIG. 2(B) is a top view showing a light-emitting device. FIG. 1 is a cross-sectional view taken along the lines AB and CD in FIG. The driving circuit section (source line driving circuit) 601 shown by the dotted line controls the pixel section 602 includes a driving circuit section (gate line driving circuit) 603. Also, 604 is a sealing substrate. 605 is a seal material, and the inside surrounded by the seal material 605 is a space 607. .

[0106] The lead wiring 608 is connected to the source line driver circuit 601 and the gate line driver circuit 603. The wiring is for transmitting the signals to be input, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the 609 Although only the FPC is shown here, the FPC has a printed wiring board. The light emitting device in this specification may be a light emitting device. This includes not only the device itself, but also the state in which an FPC or PWB is attached to it. do.

[0107] Next, the cross-sectional structure will be described with reference to FIG. A source line driver circuit 601 and a pixel portion are formed. 6, one pixel in the pixel area 602 is shown.

[0108] The element substrate 610 may be made of glass, quartz, organic resin, metal, alloy, semiconductor, or the like. FRP (Fiber Reinforced Plastics), PVF (Polyvinyl It is made using a plastic substrate made of materials such as fluoride, polyester, or acrylic. That's good.

[0109] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. The transistor may be a top-type transistor or a staggered type transistor. The transistor may be a gate type transistor or a bottom gate type transistor. The semiconductor material is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and nitride. Gallium, etc., can be used. Alternatively, indium, such as In-Ga-Zn based metal oxides, Alternatively, an oxide semiconductor containing at least one of tungsten, gallium, and zinc may be used.

[0110] The crystallinity of the semiconductor material used in the transistor is not particularly limited. A semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a partially crystalline region If a semiconductor having crystallinity is used, the transistor This is preferable because it can suppress deterioration of the star characteristics.

[0111] Here, in addition to the transistors provided in the pixels and the driver circuits, It is preferable to use an oxide semiconductor for a semiconductor device such as a transistor. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor with a wider band gap than silicon, the off-state of the transistor can be improved. This allows the current in the MOSFET's low-voltage state to be reduced.

[0112] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn). In-M-Zn oxides (where M is Al, Ti, Ga, Ge, Y, Zr, Sn, It is preferable that the oxide semiconductor contains an oxide represented by the formula (1) of La, Ce or Hf. This is more preferable.

[0113] In particular, the semiconductor layer has a plurality of crystal parts, and the c-axes of the crystal parts are aligned along the surface on which the semiconductor layer is formed, Or, the oxide is oriented perpendicular to the upper surface of the semiconductor layer and has no grain boundary between adjacent crystal portions. It is preferable to use a nitride semiconductor film.

[0114] By using such materials for the semiconductor layer, fluctuations in electrical characteristics are suppressed, leading to high reliability. This makes it possible to realize a high-speed transistor.

[0115] In addition, the transistor having the above-described semiconductor layer can be used as a transistor due to its low off-state current. It is possible to hold the charge stored in the capacitor for a long period of time through such a transistor. By applying a transistor to each pixel, the gradation of the image displayed in each display area can be maintained while driving It is also possible to shut down the circuit. As a result, electronic devices with extremely low power consumption can be realized. It can be realized.

[0116] In order to stabilize the characteristics of the transistor, it is preferable to provide an undercoat film. Inorganic films such as silicon oxide film, silicon nitride film, silicon oxynitride film, and silicon nitride oxide film The insulating film can be formed in a single layer or a multilayer structure. CVD (Chemical Vapor Deposition) method (Plasma CVD method , thermal CVD method, MOCVD (Metal Organic CVD) method, etc.), ALD ( Formed using Atomic Layer Deposition (ALD), coating, printing, etc. It should be noted that the undercoat film does not have to be provided if it is not necessary.

[0117] The FET 623 indicates one of the transistors formed in the driver circuit section 601. The driving circuits are made up of various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment, a driver integrated type in which a driver circuit is formed on a substrate is shown. However, this is not necessarily required, and the drive circuit can be formed externally instead of on the substrate. .

[0118] The pixel section 602 includes a switching FET 611, a current control FET 612 and its driver. The pixel is formed by a plurality of pixels including a first electrode 613 electrically connected to the drain. However, the present invention is not limited to this, and a pixel unit may be formed by combining three or more FETs and a capacitance element. good.

[0119] An insulator 614 is formed to cover the end of the first electrode 613. It can be formed by using a photosensitive acrylic resin film of a mold.

[0120] In order to improve the coverage of the EL layer and the like to be formed later, the upper end of the insulator 614 is For example, the material of the insulator 614 is When a positive photosensitive acrylic is used, the radius of curvature (0. It is preferable that the insulating material 614 has a curved surface having a thickness of 2 μm to 3 μm. Either a negative-type photosensitive resin or a positive-type photosensitive resin can be used.

[0121] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, the material used for the first electrode 613 functioning as an anode is a material having a work function of It is desirable to use a material with a large capacitance. For example, an ITO film or an indium tin oxide film containing silicon. Indium tin oxide film, indium oxide film containing 2 to 20 wt% zinc oxide, titanium nitride film, In addition to single-layer films such as ROM film, tungsten film, Zn film, and Pt film, titanium nitride film and aluminum film are also available. A titanium nitride film and an aluminum-based film are laminated together. In addition, a three-layer structure with a silicon film can be used. The resistance is low, good ohmic contact can be achieved, and the material can also function as an anode. .

[0122] The EL layer 616 is formed by deposition using a deposition mask, inkjet printing, or spin coating. The EL layer 616 is formed by the structure described in the first embodiment. Other materials constituting the EL layer 616 include low molecular weight compounds, may be a polymer compound (including an oligomer or a dendrimer).

[0123] Furthermore, a material for a second electrode 617 formed on the EL layer 616 and functioning as a cathode As the material, materials with a small work function (Al, Mg, Li, Ca, or alloys or compounds of these) It is preferable to use a material such as MgAg, MgIn, or AlLi. In the case where the light generated in 6 is transmitted through the second electrode 617, the second electrode 617 is Thin metal films and transparent conductive films (ITO, indium oxide containing 2-20 wt% zinc oxide) It uses lamination of indium, silicon-containing indium tin oxide, zinc oxide (ZnO, etc.) It is better to do so.

[0124] Note that the first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting element. The light-emitting element is the light-emitting element described in Embodiment 1. Note that the pixel portion has a plurality of The light emitting device in this embodiment is formed with a light emitting element. The light-emitting element may include both the light-emitting element described above and a light-emitting element having a different configuration.

[0125] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealant 605. A light emitting element is disposed in a space 607 surrounded by a child substrate 610, a sealing substrate 604, and a sealant 605. 618. The space 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it can also be filled with a sealing material. A recess is formed in the sealing substrate, and a desiccant is placed there to prevent deterioration due to moisture. This is a preferable configuration.

[0126] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials are as impermeable to moisture and oxygen as possible. Materials used for the sealing substrate 604 include glass substrates, quartz substrates, and FRP (Fiber Reinforced Plastics). reinforced plastics), PVF (polyvinyl fluoride), polyester A plastic substrate made of, for example, polyester or acrylic can be used.

[0127] Although not shown in FIG. 2, a protective film may be provided on the second electrode. The protective film is an organic resin film. In addition, a protective film may be formed so as to cover the exposed portion of the sealant 605. A protective film may be formed on the front and side surfaces of the pair of substrates, the sealing layer, the insulating layer, etc. A border layer, etc. may be provided over the exposed sides.

[0128] The protective film can be made of a material that is difficult for impurities such as water to permeate. It is possible to effectively suppress the diffusion of impurities such as those mentioned above from the outside to the inside.

[0129] The materials that make up the protective film include oxides, nitrides, fluorides, sulfides, ternary compounds, and metals. Alternatively, polymers and the like can be used, for example, aluminum oxide, hafnium oxide, hafnium oxide, etc. Funium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide , titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide , cerium oxide, scandium oxide, erbium oxide, vanadium oxide or indium oxide Materials containing uranium, aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, etc. Materials, nitrides containing titanium and aluminum, oxides containing titanium and aluminum , oxides containing aluminum and zinc, sulfides containing manganese and zinc, cerium and and sulfides containing strontium, oxides containing erbium and aluminum, yttrium Materials including, for example, oxides containing lithium and zirconium can be used.

[0130] The protective film should be formed using a film formation method that provides good step coverage. One such technique is atomic layer deposition (ALD). The ALD method can be used to form a protective It is preferable to use the ALD method for films that are dense and free of cracks and pinholes. It is possible to form a protective film having reduced defects or a uniform thickness. Damage to the processed member when forming the protective film can be reduced.

[0131] For example, by forming a protective film using the ALD method, it is possible to fabricate a surface with complex unevenness or a touch panel. It is possible to form a uniform protective film with few defects on the top, sides and back of the panel. .

[0132] In the above manner, a light-emitting device manufactured using the light-emitting element described in embodiment 1 can be obtained. This can be done.

[0133] The light-emitting device in this embodiment uses the light-emitting element described in Embodiment 1; therefore, Specifically, the light-emitting device according to the first embodiment can be obtained. Since the element is a light-emitting element having a long life, a light-emitting device having good reliability can be obtained. In addition, since the light-emitting device using the light-emitting element described in Embodiment 1 has high emission efficiency, it consumes less power. It is possible to make a light emitting device with a small size.

[0134] In FIG. 3, a light emitting element that emits white light is formed, and a colored layer (color filter) is provided. FIG. 3(A) shows a substrate 1001, a base insulating layer, and a light emitting device. film 1002, gate insulating film 1003, gate electrodes 1006, 1007, 1008, the first An interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving The driving circuit section 1041, the first electrodes 1024W, 1024R, 1024G, 102 4B, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting element, and a sealing substrate 103 1, sealing material 1032, etc. are shown.

[0135] In addition, in FIG. 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue The colored layer 1034B is provided on a transparent substrate 1033. 035 may be further provided. A transparent substrate 1 on which a colored layer and a black matrix are provided. The colored layer and the black matrix are fixed to the substrate 1001. The substrate 1035 is covered with an overcoat layer 1036. The light-emitting layer is a layer where light does not pass through the colored layers and goes out to the outside, and the light passes through the colored layers of each color and goes out to the outside. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, green, or blue. This means that images can be expressed using four color pixels.

[0136] In FIG. 3B, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer An example in which a layer (1034B) is formed between the gate insulating film (1003) and the first interlayer insulating film (1020) In this way, the colored layer is provided between the substrate 1001 and the sealing substrate 1031. is also good.

[0137] In the light emitting device described above, the light is taken in toward the substrate 1001 on which the FET is formed. The light emitting device has a bottom emission structure, but the light is taken in from the sealing substrate 1031 side. The light emitting device may have a structure in which the light is emitted from the top (top emission type). A cross-sectional view of a light-emitting device is shown in FIG. 4. In this case, a substrate 1001 that does not transmit light is used. The bottom electrode is not connected to the anode of the FET and the light-emitting element until the connection electrode is fabricated. The third interlayer insulating film 1037 is then formed on the electrode 1. The third insulating film is formed to cover the 022. This insulating film may also serve as a flattening film. The insulating film 1037 may be formed using the same material as the second interlayer insulating film, or other known materials. This can be done.

[0138] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting element are anodes here. However, it may be a cathode. Also, in the case of a top emission type light emitting device as shown in FIG. In the case of the above-mentioned arrangement, it is preferable that the first electrode is a reflective electrode. The EL layer 103 has the same structure as that described in the first embodiment, and emits white light. The element structure is designed to obtain such a result.

[0139] In the top emission structure shown in Figure 4, the colored layers (red colored layer 1034R, green colored layer The sealing is performed by using a sealing substrate 1031 provided with a blue color layer 1034G and a blue color layer 1034B. The sealing substrate 1031 is provided with a black matrix disposed between the pixels. A colored layer (a red colored layer 1034R, a green colored layer 1034G) may be provided. The blue colored layer 1034B) and the black matrix are covered by the overcoat layer 1036. The sealing substrate 1031 may be covered with a light-transmitting substrate. In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, the present invention is not limited to such a case. Alternatively, full color display may be achieved using four colors (red, yellow, green, and blue) or three colors (red, green, and blue).

[0140] In a top emission type light emitting device, a microcavity structure can be suitably applied. In the light-emitting device having a microcavity structure, the first electrode is a reflective electrode and the second electrode is a semi-transparent electrode. The semi-transparent and semi-reflective electrodes are separated by a small amount. It has at least an EL layer, and at least a light-emitting layer which serves as a light-emitting region.

[0141] The reflectance of the reflective electrode for visible light is 40% to 100%, preferably 70% to 100%. %, and its resistivity is 1×10 -2 The film is assumed to be less than Ωcm. The semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%. , and its resistivity is 1×10 -2 It is assumed that the film has a resistance of less than Ωcm.

[0142] The light emitted from the light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transparent and semi-reflective electrode. The light is reflected and resonates.

[0143] The light-emitting element can be formed by changing the thickness of the transparent conductive film, the composite material, the carrier transport material, etc. By changing the optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode, Between the reflective electrode and the semi-transmissive / semi-reflective electrode, the light of the resonating wavelength is strengthened and the light of the non-resonating wavelength is strengthened. It is possible to attenuate light of wavelengths.

[0144] The light reflected by the reflective electrode and returned (first reflected light) is semi-transmitted from the light emitting layer. The light that is directly incident on the semi-reflective electrode (first incident light) interferes greatly with the reflective electrode. The optical path length of the light-emitting layer is (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the amplified It is preferable to adjust the optical distance to a wavelength that is suitable for the first emission. By matching the phase of the reflected light with that of the first incident light, the light emitted from the light-emitting layer can be amplified. do.

[0145] In the above configuration, even if the EL layer has a plurality of light-emitting layers, a single light-emitting For example, it may be combined with the above-mentioned tandem type light emitting device. In one light-emitting element, a plurality of EL layers are provided with a charge generating layer sandwiched therebetween, and each EL layer is provided with a single Alternatively, it may be applied to a configuration in which a plurality of light-emitting layers are formed.

[0146] The microcavity structure makes it possible to enhance the emission intensity of a specific wavelength in the forward direction. This allows for low power consumption. In the case of a light-emitting device that displays images using a single pixel, the yellow light emission improves brightness, and the Since a microcavity structure that matches the wavelength of each color can be applied, it is possible to produce light-emitting devices with excellent characteristics. It can be placed.

[0147] The light-emitting device in this embodiment uses the light-emitting element described in Embodiment 1; therefore, Specifically, the light-emitting device according to the first embodiment can be obtained. Since the element is a light-emitting element having a long life, a light-emitting device having good reliability can be obtained. In addition, since the light-emitting device using the light-emitting element described in Embodiment 1 has high emission efficiency, it consumes less power. It is possible to make a light emitting device with a small size.

[0148] So far, we have explained about active matrix type light emitting devices. From now on, we will discuss passive type light emitting devices. A passive matrix type light emitting device will be described. FIG. 5(A) is a perspective view showing the light-emitting device, and FIG. FIG. 5B is a cross-sectional view taken along the line XY of FIG. 5A. In FIG. 5, on a substrate 951, An EL layer 955 is provided between the electrode 952 and the electrode 956. It is covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 become thinner between one side wall and the other side wall as they approach the substrate surface. In other words, the cross section of the partition layer 954 in the short side direction is The bottom side (the side that faces the same direction as the surface direction of the insulating layer 953 and is in contact with the insulating layer 953) ) is the upper side (the side that faces in the same direction as the surface direction of the insulating layer 953 and does not contact the insulating layer 953). In this way, by providing the partition layer 954, the length of the light-emitting element caused by static electricity or the like can be reduced. In addition, the present invention can be applied to a passive matrix type light emitting device. A light emitting device having high reliability or a light emitting device having low power consumption using the light emitting element according to the embodiment 1. It may be an optical device.

[0149] The light emitting device described above has a large number of minute light emitting elements arranged in a matrix. Since it is possible to control the light emission, it can be suitably used as a display device for displaying images. It is a device.

[0150] This embodiment mode can be freely combined with other embodiment modes.

[0151] (Embodiment 3) In this embodiment mode, an example in which the light-emitting element described in Embodiment 1 is used as a lighting device will be described with reference to FIG. FIG. 6B is a top view of the lighting device, and FIG. 6A is a schematic diagram of the lighting device in FIG. ef cross-sectional view.

[0152] The lighting device in this embodiment is a first substrate 400 having a light-transmitting property and serving as a support. The first electrode 401 is formed on the substrate 100. In the case where light is extracted from the first electrode 401 side, the first electrode 401 is a light-transmitting The insulating film is formed from a material having the following properties.

[0153] A pad 412 for supplying a voltage to the second electrode 404 is formed on the substrate 400 .

[0154] An EL layer 403 is formed on the first electrode 401. The EL layer 403 is the same as that described in the embodiment 1. The configuration of the EL layer 103 in the above, or the combination of the light-emitting units 511, 512 and the charge generating layer 513 For details of these configurations, please refer to the relevant descriptions.

[0155] A second electrode 404 is formed to cover the EL layer 403. In the case where light is extracted from the first electrode 401 side, the second electrode The first electrode 404 is formed of a highly reflective material. A voltage is supplied by connecting

[0156] As described above, a light-emitting element having a first electrode 401, an EL layer 403, and a second electrode 404 is realized. The lighting device shown in the embodiment has the light-emitting element having high light-emitting efficiency. Therefore, the lighting device in this embodiment can be a lighting device with low power consumption.

[0157] The substrate 400 on which the light emitting element having the above-mentioned structure is formed and the sealing substrate 407 are sealed with a sealant 4. The lighting device is completed by fixing and sealing the components using the sealant 405 and 406. Either one of 5 and 406 may be used. Also, the inner seal material 406 (see FIG. 6(B)) (not shown) can also be mixed with a desiccant to absorb moisture. This leads to improved reliability.

[0158] In addition, the pad 412 and a part of the first electrode 401 are extended outside the sealing materials 405 and 406. By providing a 100mV output, it can be used as an external input terminal. An IC chip 420 incorporating such a function may also be provided.

[0159] As described above, the lighting device described in this embodiment uses the light-emitting element described in embodiment 1 as the EL element. In addition, the light emitting device can be made to have low power consumption. It can be placed.

[0160] (Embodiment 4) In this embodiment mode, examples of electronic devices each including the light-emitting element described in Embodiment 1 will be described. The light-emitting element described in the first embodiment has a long life and is a highly reliable light-emitting element. As a result, the electronic device described in this embodiment has a highly reliable light-emitting portion. It may be an electronic device.

[0161] As an example of an electronic device to which the light-emitting element is applied, a television set (television, (also called revision receivers), computer monitors, digital cameras, digital Video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) ), portable game machines, personal digital assistants, audio playback devices, pachinko machines and other large game machines, etc. Specific examples of these electronic devices are shown below.

[0162] FIG. 7A shows an example of a television device. The television device includes a housing 710. A display unit 7103 is built into the display unit 1. Also, in this embodiment, a stand 7105 is used to support the display unit 1. The display unit 7103 can display images. The display portion 7103 has the light-emitting elements described in Embodiment 1 arranged in a matrix. It is composed.

[0163] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control. The remote control device 7110 includes an operation key 7109. This allows you to control the channel and volume, and the image displayed on the display unit 7103 In addition, the remote control operation device 7110 can be operated. A display portion 7107 for displaying information output from the image forming apparatus may be provided.

[0164] The television set is assumed to be equipped with a receiver and a modem. It can receive television broadcasts and can also communicate by wire or wirelessly via a modem. By connecting to a network, communication can be one-way (sender to receiver) or two-way (sender to It is also possible to communicate information between the sender and the recipient, or between the recipients themselves.

[0165] FIG. 7(B1) shows a computer, which includes a main body 7201, a housing 7202, a display unit 7203, and a keyboard. keyboard 7204, external connection port 7205, pointing device 7206, etc. In addition, the computer has the light-emitting elements described in the first embodiment arranged in a matrix. The display portion 7203 is used for the computer shown in FIG. The computer shown in FIG. 7B2 may have a keyboard 720. 4. A second display unit 7210 is provided instead of the pointing device 7206. The second display unit 7210 is a touch panel type. Input can be made by operating the input display with a finger or a special pen. In addition, the second display unit 7210 can display not only input images but also other images. The display unit 7203 may also be a touch panel. Two screens are connected by a hinge. This can cause problems such as scratching or breaking the screen when storing or transporting the device. It is also possible to prevent the occurrence of holes.

[0166] FIG. 7C shows a portable game machine that is composed of two housings, a housing 7301 and a housing 7302. The housing 7301 is connected to the connector 7303 so as to be openable and closable. A display portion 7304 in which the light-emitting elements according to embodiment 1 are arranged in a matrix is ​​incorporated. A display portion 7305 is incorporated in the housing 7302. The gaming machine also includes a speaker unit 7306, a recording medium insertion unit 7307, and an LED lamp 73 08, input means (operation keys 7309, connection terminals 7310, sensors 7311 (force, displacement, position Position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemicals, sound, time , hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays It is equipped with a microphone 7312) and a portable The configuration of the band-type gaming machine is not limited to the above, and at least the display unit 7304 and the display unit 7 The light-emitting elements described in the embodiment 1 are arranged in a matrix on either or both of the electrodes 305. It is sufficient to use the display unit manufactured by the manufacturer, and other accessories may be provided as appropriate. The portable game machine shown in FIG. 7(C) can be used to play a program or data recorded on a recording medium. The function of reading the data and displaying it on the display unit, and wirelessly communicating with other portable gaming machines to transmit information The functions of the portable gaming machine shown in FIG. 7(C) are not limited to these. It can have a variety of functions.

[0167] FIG. 7D shows an example of a mobile terminal. The mobile phone is built in a housing 7401. In addition to the display unit 7402, the operation buttons 7403, the external connection port 7404, the speaker 740 The mobile phone 7400 includes a microphone 7406 and the like. The display portion 7402 has light-emitting elements arranged in a matrix.

[0168] In the mobile terminal shown in FIG. 7D, information is input by touching the display portion 7402 with a finger or the like. In this case, the user can make a call or write an email. An operation such as pressing a key or the like can be performed by touching the display portion 7402 with a finger or the like.

[0169] The screen of the display unit 7402 has three main modes. The first is a display mode that is mainly used for displaying images. The first mode is a display mode, the second is an input mode for inputting information such as characters, and the third mode is a display mode. This is a display + input mode that combines the display mode and the input mode.

[0170] For example, when making a call or composing an e-mail, the display unit 7402 is used to input characters. The main character input mode is to input characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402. I wish.

[0171] In addition, the mobile terminal may include a sensor for detecting the inclination, such as a gyro or an acceleration sensor. By providing a device, the orientation of the mobile terminal (vertical or horizontal) can be determined and the screen display of the display portion 7402 can be displayed. The display can be switched automatically.

[0172] The screen mode can be changed by touching the display portion 7402 or by operating the housing 7401. This is done by operating the button 7403. Also, depending on the type of image displayed on the display unit 7402, For example, the image signal to be displayed on the display unit is a moving image. If it is data, the mode is switched to display mode, and if it is text data, the mode is switched to input mode.

[0173] In the input mode, the optical sensor of the display unit 7402 detects a signal and displays If there is no input by touch operation of the part 7402 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the normal mode to the display mode.

[0174] The display portion 7402 can also function as an image sensor. By touching the palm or fingers of the user on the sensor 02 and capturing an image of the palm print or fingerprint, the user can be authenticated. In addition, a backlight that emits near-infrared light to the display unit or a sensing light that emits near-infrared light By using a source, it is also possible to image finger veins, palm veins, etc.

[0175] Note that the configuration shown in this embodiment mode is a combination of the configurations shown in Embodiment Modes 1 to 4. They can be used in combination.

[0176] As described above, the light-emitting device including the light-emitting element described in the first embodiment has a wide range of applications. The light emitting device described in the first embodiment can be applied to electronic devices in various fields. By using the light-emitting element, a highly reliable electronic device can be obtained.

[0177] FIG. 8 shows an example of a liquid crystal display device in which the light-emitting element according to the first embodiment is applied to a backlight. The liquid crystal display device shown in FIG. 8 includes a housing 901, a liquid crystal layer 902, a backlight unit The liquid crystal layer 902 is connected to a driver IC 905. In addition, the backlight unit 903 uses the light-emitting element described in embodiment 1. Terminal 906 provides the electrical current.

[0178] By applying the light-emitting element described in embodiment 1 to a backlight of a liquid crystal display device, A backlight with reduced power consumption can be obtained. This allows the creation of a surface-emitting lighting device, which can also be made larger. This makes it possible to increase the area of ​​the backlight, and therefore the area of ​​the liquid crystal display device. The light emitting device using the light emitting element according to the first embodiment can be made thinner than the conventional light emitting device. This also enables the display device to be made thinner.

[0179] FIG. 9 shows an example in which the light-emitting element described in Embodiment 1 is used in a desk lamp, which is a lighting device. The desk lamp shown in FIG. 9 has a housing 2001 and a light source 2002. For this purpose, the lighting device described in the third embodiment may be used.

[0180] FIG. 10 shows an example in which the light-emitting element described in Embodiment 1 is used as an indoor lighting device 3001. Since the light-emitting element described in Embodiment 1 is a highly reliable light-emitting element, In addition, the light-emitting element described in Embodiment 1 can be made large in area. Therefore, the light emitting device can be used as a large-area lighting device. Since the optical element is thin, it can be used as a thin lighting device.

[0181] The light-emitting element described in the first embodiment can be mounted on the windshield or dashboard of an automobile. FIG. 11 shows a case where the light-emitting element described in the first embodiment is applied to a windshield or a door of an automobile. The display area 5000 to the display area 5005 are examples of the embodiment. 1 is a display provided using the light-emitting element according to embodiment 1.

[0182] In this embodiment, the display area 5000 and the display area 5001 are provided on the windshield of a car. The light-emitting element according to the first embodiment is a display device having the light-emitting element according to the first embodiment. By making the first electrode and the second electrode from light-transmitting electrodes, the opposite side can be seen through. In this case, a display device in a so-called see-through state can be obtained. If the sensor is installed on the windshield of a car, it can be installed without obstructing the view. In addition, when a transistor for driving is provided, an organic semiconductor material Transistors that have light-transmitting properties, such as organic transistors using It is advisable to use a transistor.

[0183] The display region 5002 is a display having the light-emitting element described in the first embodiment provided in the pillar portion. The display area 5002 displays an image captured by an imaging means provided on the vehicle body. This can compensate for the visibility obstructed by the pillars. The display area 5003 provided on the board portion allows the view outside the car to be displayed without being blocked by the car body. By projecting images from an imaging device installed in the vehicle, blind spots are filled and safety is improved. By projecting images to complement the invisible parts, it becomes possible to create a more natural and unnatural appearance. This allows for easy safety checks.

[0184] The display area 5004 and the display area 5005 display navigation information, a speedometer, a tachometer, and a mileage. , fuel, gear status, air conditioning settings and much more. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in the display areas 5000 to 5003. The display areas 5000 to 5005 can also be used as lighting devices.

[0185] 12(A) and 12(B) show an example of a tablet terminal that can be folded in half. FIG. 9(A) shows the tablet terminal in an open state. The tablet terminal includes a housing 9630, a display unit 9631a, Display unit 9631b, display mode changeover switch 9034, power switch 9035, power saving A force mode changeover switch 9036, a fastener 9033, and an operation switch 9038 are provided. The tablet terminal displays a light-emitting device including the light-emitting element described in Embodiment 1. The insulating film is used for one or both of the portion 9631a and the display portion 9631b.

[0186] A part of the display unit 9631a can be used as a touch panel area 9632a. Data can be input by touching the operation keys 9637. In a, as an example, half of the area has a display function only, and the other half Although a configuration having a touch panel function is shown, the present invention is not limited to this configuration. The entire area of ​​the display unit 963 a may have a touch panel function. The entire surface of the display 9631a is used as a touch panel by displaying keyboard buttons, and the display 9631b is used as a display screen. It can be used as a surface.

[0187] In addition, in the display unit 9631b, as in the display unit 9631a, The area can be a touch panel area 9632b. The display can be changed by touching the area where the display change button 9639 is displayed with your finger or a stylus. A keyboard button can be displayed on the display unit 9631b.

[0188] In addition, when the touch panel area 9632a and the touch panel area 9632b are touched simultaneously, You can also input it.

[0189] A display mode changeover switch 9034 is used to change the display orientation, such as portrait or landscape. You can choose between black and white and color display. The 9036 is a tablet-type device that detects external light during use using a built-in light sensor. The tablet device has a light sensor, which can adjust the display brightness to suit the amount of light. In addition to the sensor, other detection devices such as gyro, acceleration sensor, etc. that detect the inclination are also included. It may be built-in.

[0190] FIG. 12A shows an example in which the display area of ​​the display portion 9631b is the same as that of the display portion 9631a. However, there is no particular limitation, and one size may be different from the other size. For example, one display panel may have a higher resolution than the other. It is also possible to use the following.

[0191] FIG. 12B shows the tablet terminal in the closed state. 9630, solar cell 9633, charge / discharge control circuit 9634, battery 9635, DCDC An example in which a converter 9636 is provided is shown. Note that in FIG. 12B, a charge / discharge control circuit 9634 As an example, a configuration having a battery 9635 and a DC-DC converter 9636 is shown. is doing.

[0192] In addition, since the tablet device can be folded in half, the housing 9630 can be folded when not in use. Therefore, the display portions 9631a and 9631b can be protected, and thus the durability can be improved. This makes it possible to provide a tablet terminal that is highly durable and reliable even for long-term use.

[0193] In addition, the tablet terminals shown in Figs. 12(A) and 12(B) can store various information. Functions for displaying information (still images, videos, text images, etc.), calendars, dates, or times, etc. A function to display information on the display unit, and a function to operate or edit the information displayed on the display unit by touch input. It has the function of inputting information, the function of controlling processing by various software (programs), etc. This can be done.

[0194] The solar cell 9633 attached to the surface of the tablet device supplies power to the touch panel, The solar cell 9633 can supply the light to a display unit, a video signal processor, or the like. When installed on one or both sides of the 9630 housing, it allows efficient charging of the 9635 battery. This is preferable because it is possible to configure the above.

[0195] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. ) shows a block diagram and explains. In FIG. 12(C), a solar cell 9633, a battery 96 35, DC-DC converter 9636, converter 9638, switches SW1 to SW3, The figure shows a display unit 9631, a battery 9635, and a DC-DC converter 9636. 12B, the converter 9638 and the switches SW1 to SW3 form a charge / discharge control circuit shown in FIG. This corresponds to route 9634.

[0196] First, an example of operation in which power is generated by the solar cell 9633 using external light will be described. The power generated by the solar cell is converted to a DCD voltage to charge the Battery 9635. The voltage is increased or decreased by the C converter 9636. When the power charged by the solar battery 9633 is used, switch SW1 is turned on and the converter The voltage is increased or decreased by a power supply 9638 to a voltage required for the display unit 9631. When the display on the display unit 9631 is not displayed, turn SW1 off and SW2 on to turn on the back It would be best to configure it to charge the Terry 9635.

[0197] Although the solar cell 9633 is shown as an example of a power generating means, the power generating means is not particularly Other power generating devices such as, but not limited to, piezoelectric elements (piezo elements) and thermoelectric conversion elements (Peltier elements) may also be used. The battery 9635 may be charged by a wireless (non-contact) means. It can be combined with a non-contact power transmission module that transmits and receives power to charge, or other charging methods. The power generating means may be omitted.

[0198] In addition, if the display unit 9631 is provided, the tablet terminal shown in FIG. Not limited.

[0199] 13(A) to 13(C) show a foldable portable information terminal 9310. FIG. 13A shows a portable information terminal 9310 in an unfolded state. FIG. 13B shows a portable information terminal 9310 in an unfolded state or A portable information terminal 9310 is shown in a folded state changing from one to the other. FIG. 13C shows the portable information terminal 9310 in a folded state. The foldable design is highly portable and unfolds for a seamless, large viewing area. This provides excellent visibility of the display.

[0200] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. The display panel 9311 is a touch panel equipped with a touch sensor (input device). The display panel 9311 may be a display panel (input / output device). The portable information terminal 9310 is in an unfolded state by bending the two housings 9315. The light-emitting device according to one embodiment of the present invention can be reversibly transformed from a folded state to a folded state. It can be used for a display panel 9311. A display area 931 in the display panel 9311 Reference numeral 2 denotes a display area located on the side of the portable information terminal 9310 in a folded state. Area 9312 contains information icons and shortcuts to frequently used apps and programs. You can display information such as the date, time, and date, and launch apps smoothly. do. EXAMPLES

[0201] In this example, a light-emitting element 1 according to one embodiment of the present invention and a comparative light-emitting element 1 described in Embodiment 1 The structural formulas of the organic compounds used in the light-emitting element 1 and the comparative light-emitting element 1 are shown below. show.

[0202] [ka]

[0203] (Method of manufacturing light-emitting element 1) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0204] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0205] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0206] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0207] Next, N-(1,1'-biphenyl) represented by the above structural formula (ii) was deposited on the hole injection layer 111. 4-(9-phenyl-9H-carbazole-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole- 3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) was The first hole transport layer 112-1 is formed by deposition so as to have a film thickness of 1.0 m. On 112-1, 4-(1-naphthyl)-4'-phenyl Triphenylamine (abbreviation: αNBA1BP) was evaporated to a thickness of 5 nm to form the second A hole transport layer 112-2 is formed, and a compound represented by the above structural formula (iv) is formed on the second hole transport layer 112-2. 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carba A third hole transport layer 112 was formed by depositing PCPPn (abbreviation: PCPPn) to a thickness of 5 nm. -3 was formed.

[0208] Next, 7-[4-(10-phenyl-9-anthryl) phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above N,N'-bis(3-methylphenyl)-N,N'-bis[3 -(9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCz PA: 1,6mMemFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Formed.

[0209] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0210] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition to fabricate the light-emitting element 1 of this example.

[0211] (Method of manufacturing comparative light-emitting element 1) The comparative light-emitting element 1 has a first hole transport layer 112-1 and a second hole transport layer 1 The same as light-emitting element 1, except that a 25 nm film of PCBBiF was deposited instead of the two layers of 12-2. That is, the comparative light-emitting element 1 was fabricated without forming the second hole transport layer 112-2. It can be called an element.

[0212] The device structures of the light-emitting element 1 and the comparative light-emitting element 1 are summarized in the following table.

[0213] [Table 1]

[0214] The light-emitting element 1 and the comparative light-emitting element 1 were placed in a glove box with a nitrogen atmosphere. The process of sealing the element with a glass substrate to prevent it from being exposed to the atmosphere (sealing material is applied around the element) After performing UV treatment during sealing and heat treatment at 80°C for 1 hour, the initial characteristics of these light-emitting devices were The performance and reliability of the device were measured. The measurements were performed at room temperature (25°C). I did.

[0215] FIG. 14 shows the luminance vs. current density characteristics of the light-emitting element 1 and the comparative light-emitting element 1, and FIG. The luminance-voltage characteristics are shown in Fig. 15, the current-voltage characteristics are shown in Fig. 17, and the external quantum efficiency-luminance characteristics are shown in Fig. 18. The luminance characteristics are shown in FIG. 18, and the emission spectrum is shown in FIG. 19. m 2 The main characteristics of the area are shown in Table 2.

[0216] [Table 2]

[0217] 14 to 19 and Table 2, the light-emitting element 1 of one embodiment of the present invention has a second hole-transport layer It is a blue light-emitting device having better driving voltage and efficiency than the comparative light-emitting device 1 not having 112-2. It was found that...

[0218] In addition, the initial brightness is 5000cd / m 2 and the current density is constant. A graph showing the change in luminance due to the change in the luminance is shown in FIG. The light-emitting element 1, which is the child, shows a large decrease in luminance with the accumulation of driving time compared to the comparative light-emitting element 1. It was found that the emission was very small and the light-emitting element had a long life.

[0219] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method is shown below.

[0220] The measurement device used was an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model). The solution used in the CV measurements was dehydrated dimethyl ether. Dimethylformamide (DMF) (Aldrich Co., Ltd., 99.8%, Catalog No. 227 05-6) was used as the supporting electrolyte, tetra-n-butylammonium perchlorate (nB u4NClO4) (Tokyo Chemical Industry Co., Ltd., catalog number: T0836) was added at 100 mmol / The measurement target was then dissolved in water to a concentration of 2 mmol / L. The working electrode was a platinum electrode (PT E platinum electrode) as an auxiliary electrode, and a platinum electrode (B.A.S. Co., Ltd., VC-3 P t counter electrode (5 cm)) and Ag / Ag as the reference electrode. + Electrode (B.A.E. The measurements were performed at room temperature (20 to 32°C). The scan speed during CV measurement was standardized to 0.1 V / sec. The oxidation potential Ea [V] and reduction potential Ec [V] of the reference electrode were measured. The intermediate potential of the reduction wave was set as Ec, and the intermediate potential of the reduction-oxidation wave was set as Ec. The potential energy of the reference electrode with respect to the vacuum level is -4.94 eV. Since it is known that the HOMO level [eV] = -4.94-Ea, the LUMO level [eV ]=-4.94-Ec. Calculate the HOMO and LUMO levels. It is possible.

[0221] [Table 3]

[0222] As shown in the table, the HOMO level of the second hole transport material in the material used for the light-emitting element 1 is The HOMO level of the host material is deeper than the HOMO level of the first hole transport material. The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the light-emitting material is deeper than the HOMO level of the host material. It's also shallow.

[0223] The HOMO level of the first hole transport material, PCBBiF, is shallow at -5.36 eV. It can easily cause charge separation by interacting with the LUMO level of N, -4.41 eV.

[0224] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and P The HOMO level of CBBiF is 0.33 eV lower than that of the luminescent material 1,6 Since the HOMO level of mMemFLPAPrn is -5.40 eV, the difference is 0.04 Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, The light-emitting element has a structure in which the hole transport layer 112-1 and the light-emitting layer 113 are formed in contact with each other. In the case of electrons, it is thought that hole injection into the light-emitting material is likely to occur. When holes are injected into the optical material, the holes are transported by the light-emitting material to the first hole transport layer 112-1 and emit light. There is a risk that the luminous region will be concentrated and degradation will be accelerated. Holes are less likely to enter the host material of the light-emitting layer from the hole transport material of the hole transport layer 112-1. As a result, holes are accumulated in the hole transport material and electrons are accumulated in the host material. Between the hole transport material and the host material, an exciplex with lower energy than that of the light emitting material is formed. This can cause problems such as a decrease in luminous efficiency.

[0225] In the light-emitting element 1, the second hole transport layer 112-2 is made of a material having a shallower HOMO level than the host material. However, by using a second hole transport material having a deeper HOMO level than the first hole transport material, Therefore, first, holes are injected from the first hole transport layer 112-1 to the second hole transport layer 112-2. The HOMO level of the second hole transport material, αNBA1BP, is -5.52 eV. The difference between this and the first hole transport material, PCBBiF, is small at 0.16 eV. Holes are smoothly injected from the first hole transport layer 112-1 to the second hole transport layer 112-2. will be done.

[0226] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. Therefore, a barrier of about 0.17 eV exists between the second hole transport material and the host material. Normally, holes are injected without any problem. However, the H The OMO level is -5.40 eV, so there is no barrier. Therefore, the holes end up in the host material. When holes are directly injected into the light-emitting material, as described above, As a result, problems such as accelerated deterioration and reduced luminous efficiency are likely to occur.

[0227] In the light-emitting element 1 which is a light-emitting element of one embodiment of the present invention, the second hole-transport layer 112-2 and A third hole transport layer 112-3 was further provided between the light emitting layer 113. The HOMO level of the third hole transport material in 112-3, PCPPn, is -5.80. eV, which is deeper than the host material. Therefore, there is no barrier to hole injection into the host material. In addition, the injection of holes into the host material is prioritized from the mixing ratio of the host material and the light-emitting material. The difference in HOMO level with the second hole transport material is 0.28 eV (0.3 eV with one significant digit). (within 100 nm) and there is no problem with the injection of holes from the second hole transport material to the third hole transport material. will be done.

[0228] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the region does not concentrate in one part but spreads over the light-emitting layer 113, deterioration is not promoted and the life is extended. The light-emitting element had good luminous efficiency.

[0229] On the other hand, the comparative light-emitting element 1 does not have the second hole transport layer 112-2. There is a large difference in HOMO level between the first hole transport layer 112-1 and the third hole transport layer 112-3. This makes it difficult for holes to be injected into the light-emitting layer 113, and the driving voltage increases. In addition, since it becomes difficult to inject holes, electrons are transported between the light-emitting layer 113 and the hole transport layer 114. This causes problems such as electrons accumulating at the interface with the hole transport layer and electrons leaking out into the hole transport layer. If the number of electrons increases, the light-emitting region becomes biased, which may adversely affect the life of the light-emitting element. When the dopant leaks into the hole transport layer, carrier recombination also occurs in the hole transport layer. This leads to a decrease in the luminous efficiency due to a relative decrease in the probability of emitting light from the hole transport material, and deterioration of the hole transport material. In this way, the light-emitting element 1 of one embodiment of the present invention has the following characteristics: Since these problems can be effectively suppressed, a light-emitting device having very good characteristics can be obtained. It became. EXAMPLES

[0230] In this example, the light-emitting element 2 and the light-emitting element 3 according to one embodiment of the present invention described in Embodiment 1 will be described. The structural formulae of the organic compounds used in the light-emitting elements 2 and 3 are shown below.

[0231] [ka]

[0232] (Method of manufacturing light-emitting element 2) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0233] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0234] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0235] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0236] Next, N-(1,1'-biphenyl) represented by the above structural formula (ii) was deposited on the hole injection layer 111. 4-(9-phenyl-9H-carbazole-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole- 3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) was The first hole transport layer 112-1 is formed by deposition so as to have a film thickness of 1.0 m. 112-1, 4-phenyl-4'-(9-phenyl) Fluoren-9-yl)triphenylamine (abbreviation: BPAFLP) to a thickness of 5 nm The second hole transport layer 112-2 is formed by vapor deposition in the manner described above. The 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl)- Phenyl-9H-carbazole (abbreviation: PCzN2) was evaporated to a thickness of 15 nm. A third hole transport layer 112-3 was formed.

[0237] Next, 7-[4-(10-phenyl-9-anthryl)fluorene represented by the above structural formula (v) phenyl-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above structure N,N'-bis(3-methylphenyl)-N,N'-bis[3- (9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCzP A: 1,6mMeMFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Successful.

[0238] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0239] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition to fabricate the light-emitting element 2 of this example.

[0240] (Method of Manufacturing Light-Emitting Element 3) The light-emitting element 3 was fabricated by replacing BPAFLP in the second hole transport layer 112-2 of the light-emitting element 2 with αNBA The light-emitting device was fabricated in the same manner as in the light-emitting device 2, except that 1BP was used.

[0241] The device structures of the light-emitting elements 2 and 3 are summarized in the table below.

[0242] [Table 4]

[0243] The light emitting element 2 and the light emitting element 3 are placed in a glove box with a nitrogen atmosphere, and the light emitting element is The process of sealing the element with a glass substrate to prevent it from being exposed to air (applying a sealant around the element, After performing UV treatment during sealing and heat treatment at 80°C for 1 hour, the initial characteristics and The measurements were performed at room temperature (25°C). .

[0244] FIG. 21 shows the luminance-current density characteristics of the light-emitting element 2 and the light-emitting element 3, and FIG. 22 shows the current efficiency-luminance characteristics of the light-emitting element 2 and the light-emitting element 3. 2. The luminance-voltage characteristics are shown in Fig. 23, the current-voltage characteristics in Fig. 24, and the external quantum efficiency-luminance characteristics in Fig. 25. The emission spectrum is shown in FIG. 25 and the emission spectrum is shown in FIG. 2 Attached The main characteristics of the current model are shown in Table 5.

[0245] [Table 5]

[0246] 21 to 26 and Table 4, all of the light-emitting elements are blue light-emitting elements with good characteristics. I found out that...

[0247] In addition, the initial brightness is 5000cd / m 2 and the current density is constant. A graph showing the change in luminance is shown in Fig. 27. As shown in Fig. 27, the light-emitting element of one embodiment of the present invention The light-emitting elements 2 and 3 have a small decrease in luminance due to accumulation of driving time and have a long life. It was found to be a light-emitting element.

[0248] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method was the same as in Example 1.

[0249] [Table 6]

[0250] [Table 7]

[0251] As shown in the table, in the materials used in the light-emitting element 2 and the light-emitting element 3, the second hole transport material H The OMO level is deeper than the HOMO level of the first hole transport material and is closer to the HOMO level of the host material. is deeper than the HOMO level of the second hole transport material, and the HOMO level of the third hole transport material is The HOMO level of the light-emitting material is deeper than that of the host material. Shallower than the OMO level.

[0252] The HOMO level of the first hole transport material, PCBBiF, is shallow at -5.36 eV. It can easily cause charge separation by interacting with the LUMO level of N, -4.41 eV.

[0253] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and P The HOMO level of CBBiF is 0.33 eV lower than that of the luminescent material 1,6 Since the HOMO level of mMemFLPAPrn is -5.40 eV, the difference is 0.04 Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, The light-emitting element has a structure in which the hole transport layer 112-1 and the light-emitting layer 113 are formed in contact with each other. In the case of electrons, it is thought that hole injection into the light-emitting material is likely to occur. When holes are injected into the optical material, the holes are transported by the light-emitting material to the first hole transport layer 112-1 and emit light. There is a risk that the luminous region will be concentrated and degradation will be accelerated. Holes are less likely to enter the host material of the light-emitting layer from the hole transport material of the hole transport layer 112-1. As a result, holes are accumulated in the hole transport material and electrons are accumulated in the host material. Between the hole transport material and the host material, an exciplex with lower energy than that of the light emitting material is formed. This can cause problems such as a decrease in luminous efficiency.

[0254] In the light-emitting element 2 and the light-emitting element 3, the second hole transport layer 112-2 is made of a material selected from H A second hole transport material that has a shallower OMO level but a deeper HOMO level than the first hole transport material. First, the first hole transport layer 112-1 to the second hole transport layer 112 The HOMO of BPAFLP, which is the second hole transport material of the light-emitting element 2, is The energy level is -5.51 eV, which is 0.15 eV lower than the first hole transport material, PCBBiF. In addition, the HOMO of the second hole transport material αNBA1BP of the light-emitting element 3 is as small as 1 eV. The energy level is -5.52 eV, which is 0.16 eV lower than the first hole transport material, PCBBiF. eV. Therefore, the hole transport layer 112-1 to the hole transport layer 112-2 Holes are smoothly injected into the

[0255] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. A barrier of about 0.17 to 0.18 eV exists between the second hole transport material and the host material. Normally, holes are injected without any problem. The HOMO level of the optical material is -5.40 eV, so there is no barrier. When holes are directly injected into the light-emitting material, the above-mentioned As described above, problems such as accelerated deterioration and reduced luminous efficiency are likely to occur.

[0256] In the light-emitting element 1 which is a light-emitting element of one embodiment of the present invention, the second hole-transport layer 112-2 and A third hole transport layer 112-3 was provided between the light emitting layer 113. The HOMO level of the third hole transport material, PCzN2, in -3 is -5.71 eV. The hole injection depth is roughly the same as that of the host material (slightly deeper). There is no wall, and the mixture ratio of the host material and the light-emitting material favors the injection of holes into the host material. In addition, the difference in HOMO level with the second hole transport material is 0.20 eV and 0.19 eV (effective (within 0.3 eV for one digit) and the positive charge from the second hole transport material to the third hole transport material The injection of the holes is also carried out without any problems.

[0257] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the light is not concentrated in a certain area but spreads throughout the light-emitting layer 113, deterioration is not accelerated and the lifespan and The light-emitting element had good luminous efficiency. EXAMPLES

[0258] In this example, the light-emitting element 4 according to one embodiment of the present invention described in Embodiment 1 will be described. The structural formula of the organic compound used in the light-emitting element 4 is shown below.

[0259] [ka]

[0260] (Method of manufacturing light-emitting element 4) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0261] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0262] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0263] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0264] Next, N-(1,1'-biphenyl) represented by the above structural formula (ii) was deposited on the hole injection layer 111. 4-(9-phenyl-9H-carbazole-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole- 3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) was The first hole transport layer 112-1 is formed by deposition so as to have a film thickness of 1.0 m. 4,4'-di-(1-naphthyl)-4''- Phenyltriphenylamine (abbreviation: αNBB1BP) was evaporated to a thickness of 5 nm. On the second hole transport layer 112-2, a compound represented by the above structural formula ( iv) 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H -Carbazole (abbreviation: PCPPn) was evaporated to a thickness of 5 nm to form a third hole transport A layer 112-3 was formed.

[0265] Next, 7-[4-(10-phenyl-9-anthryl)fluorene represented by the above structural formula (v) phenyl-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above structure N,N'-bis(3-methylphenyl)-N,N'-bis[3- (9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCzP A: 1,6mMeMFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Successful.

[0266] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0267] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition, and the light-emitting element 4 of this example was fabricated.

[0268] The device structure of the light-emitting device 4 is summarized in the table below.

[0269] [Table 8]

[0270] The light emitting element 4 is placed in a glove box with a nitrogen atmosphere so that the light emitting element is not exposed to the atmosphere. The process of sealing the element with a glass substrate (applying a sealant around the element and applying UV light during sealing) After the device was subjected to a thermal treatment at 80°C for 1 hour, the initial characteristics and reliability of the light-emitting devices were evaluated. The measurements were carried out at room temperature (an atmosphere maintained at 25°C).

[0271] FIG. 28 shows the luminance vs. current density characteristics of the light-emitting element 4, FIG. 29 shows the current efficiency vs. luminance characteristics, and FIG. The voltage characteristics are shown in Fig. 30, the current-voltage characteristics in Fig. 31, the external quantum efficiency-luminance characteristics in Fig. 32, and the emission The optical spectrum is shown in FIG. 33. Also, the 1000 cd / m 2 Major nearby The characteristics are shown in Table 8.

[0272] [Table 9]

[0273] 28 to 33 and Table 6, it is clear that the light-emitting element 4 is a blue light-emitting element with excellent characteristics. It was.

[0274] In addition, the initial brightness is 5000cd / m 2 and the current density is constant. A graph showing the change in luminance due to the change in the luminance is shown in FIG. The light-emitting element 4, which is a child of the device, is a light-emitting element that has a long life and shows little decrease in luminance due to accumulation of driving time. I discovered something.

[0275] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method was the same as in Example 1.

[0276] [Table 10]

[0277] As shown in the table, the HOMO level of the second hole transport material in the material used for the light-emitting element 4 is The HOMO level of the host material is deeper than the HOMO level of the first hole transport material. The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the light-emitting material is deeper than the HOMO level of the host material. It's also shallow.

[0278] The HOMO level of the first hole transport material, PCBBiF, is shallow at -5.36 eV. It can easily cause charge separation by interacting with the LUMO level of N, -4.41 eV.

[0279] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and P The HOMO level of CBBiF is 0.33 eV lower than that of the luminescent material 1,6 Since the HOMO level of mMemFLPAPrn is -5.40 eV, the difference is 0.04 Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, The light-emitting element has a structure in which the hole transport layer 112-1 and the light-emitting layer 113 are formed in contact with each other. In the case of electrons, it is thought that hole injection into the light-emitting material is likely to occur. When holes are injected into the optical material, the holes are transported by the light-emitting material to the first hole transport layer 112-1 and emit light. There is a risk that the luminous region will be concentrated and degradation will be accelerated. Holes are less likely to enter the host material of the light-emitting layer from the hole transport material of the hole transport layer 112-1. As a result, holes are accumulated in the hole transport material and electrons are accumulated in the host material. Between the hole transport material and the host material, an exciplex with lower energy than that of the light emitting material is formed. This can cause problems such as a decrease in luminous efficiency.

[0280] In the light-emitting element 4, the second hole transport layer 112-2 is made of a material having a shallower HOMO level than the host material. The second hole transport material has a deeper HOMO level than the first hole transport material. As a result, holes are first transported from the first hole transport layer 112-1 to the second hole transport layer 112-2. The HOMO level of the second hole transport material, αNBB1BP, is -5.50 eV. The difference with PCBBiF, the first hole transport material, is small at 0.14 eV. Therefore, holes can be smoothly transported from the first hole transport layer 112-1 to the second hole transport layer 112-2. It is injected.

[0281] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. Therefore, a barrier of about 0.19 eV exists between the second hole transport material and the host material. Normally, holes are injected without any problem. However, the H The OMO level is -5.40 eV, and it injects holes from the second hole transport material to the light emitting material. Therefore, holes end up preferentially being injected into the emitting material rather than the host material. If holes are injected directly into the light-emitting material, the deterioration will be accelerated as mentioned above. This can lead to problems such as a decrease in light efficiency.

[0282] In the light-emitting element 4 which is a light-emitting element of one embodiment of the present invention, the second hole-transport layer 112-2 and A third hole transport layer 112-3 was provided between the light emitting layer 113. The HOMO level of the third hole transport material, PCPPn, in -3 is -5.80 eV. The hole injection hole is located deeper than the host material. Therefore, there is no barrier to the hole injection into the host material. The mixing ratio of the host material and the light-emitting material also favors the injection of holes into the host material. The difference in HOMO level with the hole transport material is 0.30 eV (within 0.3 eV with one significant digit) and the injection of holes from the second hole transport material to the third hole transport material can be performed without any problem. .

[0283] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since the anthracene compound is used, the driving voltage does not increase. Since the light is not concentrated in one area but spreads throughout the light-emitting layer 113, deterioration is not promoted and the lifespan is extended. The light-emitting element had good luminous efficiency. EXAMPLES

[0284] In this example, the light-emitting element 5 according to one embodiment of the present invention described in Embodiment 1 will be described. The structural formula of the organic compound used in the light-emitting element 5 is shown below.

[0285] [ka]

[0286] (Method of Manufacturing Light-Emitting Element 5) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0287] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0288] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0289] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0290] Next, on the hole injection layer 111, 9,9-dimethyl-N-phenylene sulfide represented by the above structural formula (xi) was phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]- PCBAF (abbreviation: PCBAF) was evaporated to a thickness of 20 nm to form the first A hole transport layer 112-1 is formed, and the above structural formula (iii) is formed on the first hole transport layer 112-1. 4-(1-naphthyl)-4'-phenyltriphenylamine (abbreviation: αNBA 1BP) was evaporated to a thickness of 5 nm to form a second hole transport layer 112-2, and On the hole transport layer 112-2, 3-[4-(9-phenanthroline) represented by the above structural formula (iv) PCPPn) was applied to a 5 mm thick The third hole transport layer 112-3 was formed by deposition so as to have a thickness of 100 nm.

[0291] Next, 7-[4-(10-phenyl-9-anthryl) phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above N,N'-bis(3-methylphenyl)-N,N'-bis[3 -(9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCz PA: 1,6mMemFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Formed.

[0292] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0293] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition to fabricate the light-emitting element 5 of this example.

[0294] The device structure of the light-emitting device 5 is summarized in the table below.

[0295] [Table 11]

[0296] The light emitting element 5 is placed in a glove box with a nitrogen atmosphere so that the light emitting element is not exposed to the atmosphere. The process of sealing the element with a glass substrate (applying a sealant around the element and applying UV light during sealing) After the device was subjected to a thermal treatment at 80°C for 1 hour, the initial characteristics and reliability of the light-emitting devices were evaluated. The measurements were carried out at room temperature (an atmosphere maintained at 25°C).

[0297] FIG. 35 shows the luminance vs. current density characteristics of the light-emitting element 5, FIG. 36 shows the current efficiency vs. luminance characteristics, and Voltage characteristics are shown in Fig. 37, current-voltage characteristics in Fig. 38, external quantum efficiency-luminance characteristics in Fig. 39. The emission spectrum is shown in FIG. 40. In addition, the 1000 cd / m 2 Main in the vicinity The important characteristics are shown in Table 12.

[0298] [Table 12]

[0299] 35 to 40 and Table 8, it is clear that the light-emitting element 5 is a blue light-emitting element with excellent characteristics. It was.

[0300] In addition, the initial brightness is 5000cd / m 2 and the current density is constant. A graph showing the change in luminance due to the change in the luminance is shown in FIG. The light-emitting element 5, which is a child of the device, is a light-emitting element that has a long life and shows little decrease in luminance due to accumulation of driving time. I discovered something.

[0301] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method was the same as in Example 1.

[0302] [Table 13]

[0303] As shown in the table, in the material used in the light-emitting element 5, the HOMO level of the second hole transport material is The HOMO level of the host material is deeper than the HOMO level of the first hole transport material. The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the light-emitting material is deeper than the HOMO level of the host material. It's also shallow.

[0304] The HOMO level of the first hole transport material, PCBAF, is shallow at -5.38 eV, and HAT-CN It can easily cause charge separation by interacting with the LUMO level of -4.41 eV of

[0305] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and P The HOMO level of CBAF is 0.31 eV lower than that of the 1,6m Since the HOMO level of MemFLPAPrn is -5.40 eV, the difference is 0.02 e V. Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, The light emitting device has a structure in which the hole transport layer 112-1 and the light emitting layer 113 are formed in contact with each other. If this is assumed, hole injection into the light-emitting material is likely to occur. When holes are injected into the material, the holes are transported by the light-emitting material between the first hole transport layer 112-1 and the light-emitting layer There is a risk that the first layer may be trapped at the interface, concentrating the light-emitting region and accelerating degradation. This is because holes are less likely to enter the host material of the light-emitting layer from the hole transport material of the hole transport layer 112-1. Then, holes are accumulated in the hole transport material and electrons are accumulated in the host material. Between the hole transport material and the host material, an exciplex with lower energy than that of the light emitting material is formed. This can cause problems such as a decrease in luminous efficiency.

[0306] In the light-emitting element 5, the second hole transport layer 112-2 is made of a material having a shallower HOMO level than the host material. The second hole transport material has a deeper HOMO level than the first hole transport material. As a result, holes are first transported from the first hole transport layer 112-1 to the second hole transport layer 112-2. The HOMO level of the second hole transport material, αNBA1BP, is -5.52 eV. The difference with PCBAF, the first hole transport material, is small at 0.14 eV. In contrast, holes are smoothly injected from the first hole transport layer 112-1 to the second hole transport layer 112-2. It is entered.

[0307] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. The difference between the second hole transport material, αNBA1BP, and the host material is about 0.17 eV. Normally, holes are injected without any problem, but in the light-emitting layer 113, The HOMO level of the light-emitting material is −5.40 eV, and light is emitted from the second hole transport material. There is no barrier for holes to be injected into the material. Therefore, holes are more likely to enter the emissive material than the host material. If holes are injected directly into the light-emitting material, degradation will be accelerated as described above. This can lead to problems such as the light being accelerated and the luminous efficiency decreasing.

[0308] In light-emitting element 5 which is a light-emitting element of one embodiment of the present invention, the second hole-transport layer 112-2 and A third hole transport layer 112-3 was provided between the light emitting layer 113. The HOMO level of the third hole transport material, PCPPn, in -3 is -5.80 eV. The hole injection hole is located deeper than the host material. Therefore, there is no barrier to the hole injection into the host material. The mixing ratio of the host material and the light-emitting material also favors the injection of holes into the host material. The difference in HOMO level between the hole transport material and the material is 0.27 eV (within 0.3 eV with one significant digit). and the injection of holes from the second hole transport material to the third hole transport material can be performed without any problem. .

[0309] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the region does not concentrate in one part but spreads over the light-emitting layer 113, deterioration is not promoted and the life is extended. The light-emitting element had good luminous efficiency. EXAMPLES

[0310] In this example, the light-emitting elements 6, 7, and 8 of one embodiment of the present invention described in Embodiment 1 The structural formulas of the organic compounds used in the light-emitting elements 6 to 8 are as follows: Shown below.

[0311] [ka]

[0312] (Method of Manufacturing Light-Emitting Element 6) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0313] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0314] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0315] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0316] Next, N-(1,1'-biphenyl) represented by the above structural formula (ii) was deposited on the hole injection layer 111. 4-(9-phenyl-9H-carbazole-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole- 3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) was The first hole transport layer 112-1 is formed by deposition so as to have a film thickness of 1.0 m. 112-1, 4-(10-phenyl-9-anthryl) )-4'-(9-phenyl-9H-fluoren-9-yl)triphenylamine (abbreviation: A second hole transport layer 112-2 is formed by depositing FLPAPA to a thickness of 5 nm. On the second hole transport layer 112-2, 3-[4-(9-phenylene)- 9-phenyl-9H-carbazole (abbreviation: PCPPn) The third hole transport layer 112-3 was formed by deposition so as to have a thickness of 5 nm.

[0317] Next, 7-[4-(10-phenyl-9-anthryl) phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above N,N'-bis(3-methylphenyl)-N,N'-bis[3 -(9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCz PA: 1,6mMemFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Formed.

[0318] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0319] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition, and the light-emitting element 6 of this example was fabricated.

[0320] (Method of Manufacturing Light-Emitting Element 7) The light-emitting element 7 includes a second hole transport layer 112-2 made of a compound represented by the above structural formula (xiii). 9,9-bis[(N,N-bis-biphenyl-4-yl-amino)phenyl]-9 The light-emitting device was fabricated in the same manner as in the light-emitting device 6, except that H-fluorene (abbreviation: BPAPF) was used.

[0321] (Method of Manufacturing Light-Emitting Element 8) The light-emitting element 8 includes a second hole transport layer 112-2 made of a material represented by the above structural formula (xiv). 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA) The light-emitting device was fabricated in the same manner as in the light-emitting device 6, except that the above was used.

[0322] The device structures of the light-emitting elements 6, 7, and 8 are summarized in the table below.

[0323] [Table 14]

[0324] The light-emitting elements 6 to 8 are placed in a glove box with a nitrogen atmosphere, and the light-emitting elements are The process of sealing the element with a glass substrate to prevent it from being exposed to air (applying a sealant around the element, After performing UV treatment during sealing and heat treatment at 80°C for 1 hour, the initial characteristics and The measurements were performed at room temperature (25°C). .

[0325] FIG. 42 shows the luminance-current density characteristics of the light-emitting elements 6 to 8, and FIG. 43 shows the current efficiency-luminance characteristics of the light-emitting elements 6 to 8. 43, the luminance-voltage characteristics are shown in Fig. 44, the current-voltage characteristics are shown in Fig. 45, and the external quantum efficiency-luminance characteristics are shown in Fig. 46. The emission properties are shown in FIG. 46 and the emission spectrum in FIG. 47. 2 The main characteristics of the area are shown in Table 15.

[0326] [Table 15]

[0327] 42 to 47 and Table 15, the light-emitting elements 6 to 8 are blue light-emitting elements with good characteristics. It turned out to be a child.

[0328] In addition, the initial brightness is 5000cd / m 2 and the current density is constant. A graph showing the change in luminance is shown in Fig. 48. As shown in Fig. 48, the light-emitting element of one embodiment of the present invention The light-emitting elements 6 to 8 have a small decrease in luminance due to accumulation of driving time and have a long life. It was found to be a light-emitting element.

[0329] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method was the same as in Example 1.

[0330] [Table 16]

[0331] [Table 17]

[0332] [Table 18]

[0333] As shown in the table, in the materials used in the light-emitting elements 6 to 8, The HOMO level of the first hole transport material is deeper than the HOMO level of the host material. The HOMO level of the second hole transport material is deeper than the HOMO level of the third hole transport material. is deeper than the HOMO level of the host material. Shallower than the HOMO level.

[0334] The HOMO level of the first hole transport material, PCBBiF, is shallow at -5.36 eV. It can easily cause charge separation by interacting with the LUMO level of N, -4.41 eV.

[0335] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and P The HOMO level of CBBiF is 0.33 eV lower than that of the luminescent material 1,6 Since the HOMO level of mMemFLPAPrn is -5.40 eV, the difference is 0.04 Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, The light-emitting element has a structure in which the hole transport layer 112-1 and the light-emitting layer 113 are formed in contact with each other. In the case of electrons, it is thought that hole injection into the light-emitting material is likely to occur. When holes are injected into the optical material, the holes are transported by the light-emitting material to the first hole transport layer 112-1 and emit light. There is a risk that the luminous region will be concentrated and degradation will be accelerated. Holes are less likely to enter the host material of the light-emitting layer from the hole transport material of the hole transport layer 112-1. As a result, holes are accumulated in the hole transport material and electrons are accumulated in the host material. Between the hole transport material and the host material, an exciplex with lower energy than that of the light emitting material is formed. This can cause problems such as a decrease in luminous efficiency.

[0336] In the light-emitting elements 6 to 8, the second hole-transporting layer 112-2 is made of a HOM material rather than a host material. A second hole transport material is used that has a shallow O level but a deeper HOMO level than the first hole transport material. First, the first hole transport layer 112-1 to the second hole transport layer 112-2 are formed in the above-mentioned manner. The second hole transport material, FLPAPA (light-emitting element 6), B The HOMO levels of PAPF (light-emitting element 7) and DPhPA (light-emitting element 8) are -5.54e V, -5.50 eV, -5.53 eV, and the first hole transport material PCBBiF. The differences in the valence energy are small, 0.18 eV, 0.14 eV, and 0.17 eV, respectively. Holes are smoothly injected from the hole transport layer 112-1 to the second hole transport layer 112-2. .

[0337] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. and between the second hole transport material and the host material, 0.15 eV, 0.19 eV, and There is a barrier of about 0.16 eV. Normally, holes are injected without any problems. The HOMO level of the light-emitting material contained in the light-emitting layer 113 is −5.40 eV. There is no barrier for holes to be injected from the transport material to the light-emitting material. Therefore, the holes end up The holes are preferentially injected into the light-emitting material rather than into the host material. As described above, this can lead to problems such as accelerated deterioration and reduced luminous efficiency. stomach.

[0338] Therefore, in the light-emitting elements 6 to 8 which are light-emitting elements according to embodiments of the present invention, a second hole-transport A third hole transport layer 112-3 was further provided between the layer 112-2 and the light emitting layer 113. The HOMO level of the third hole transport material PCPPn contained in the third hole transport layer 112-3 is The potential of the hole transport layer is -5.80 eV, which is deeper than that of the host material. There is no barrier to injection, and the mixture ratio of the host material and the light-emitting material indicates that the injection of holes into the host material is dominant. The difference in HOMO level with the second hole transport material is 0.26 eV to 0.30 eV. eV (within 0.3 eV to one significant digit) and the second hole transport material to the third hole transport material Injection of holes into the material is also possible without any problems.

[0339] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the region does not concentrate in one part but spreads over the light-emitting layer 113, deterioration is not promoted and light is not emitted. The light-emitting elements 6 to 8 were light-emitting elements with good life span and luminous efficiency. EXAMPLES

[0340] In this example, the light-emitting elements 9 and 10 according to one embodiment of the present invention described in Embodiment 1 and The light-emitting element 11 will be described. The structures of the organic compounds used in the light-emitting elements 9 to 11 will be described. The formula is shown below.

[0341] [ka]

[0342] (Method of Manufacturing Light-Emitting Element 9) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0343] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0344] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0345] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0346] Next, on the hole injection layer 111, 4,4'-bis[N-(1 (N-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) was applied to a film thickness of 10 nm. A first hole transport layer 112-1 is formed by vapor deposition so as to form a first hole transport layer 112-1. to 4-(2-naphthyl)-4',4"-diphenyltrimethylsilyl group represented by the above structural formula (xvi). Phenylamine (abbreviation: BBAβNB) was evaporated to a thickness of 10 nm to form the second hole A transport layer 112-2 is formed, and a compound represented by the above structural formula (xvii) is formed on the second hole transport layer 112-2. Represented by 3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carba A third hole transport layer 1 was formed by depositing βNP2PC (abbreviation: βNP2PC) to a thickness of 10 nm. The result was a 12-3.

[0347] Next, 7-[4-(10-phenyl-9-anthryl) phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above N,N'-bis(3-methylphenyl)-N,N'-bis[3 -(9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCz PA: 1,6mMemFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Formed.

[0348] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0349] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition, and the light-emitting element 9 of this example was fabricated.

[0350] (Method of Manufacturing Light-Emitting Element 10) The light-emitting element 10 uses BBA as the material of the second hole transport layer 112-2 in the light-emitting element 9. Instead of βNB, 4-(1-naphthyl)-4',4 The other light-emitting element 9 was made of α-diphenyltriphenylamine (abbreviation: BBAαNB). was prepared similarly.

[0351] (Method of manufacturing light-emitting element 11) The light-emitting element 11 is the same as the light-emitting element 9 except that the second hole transport layer 112-2 is made of BBA Instead of βNB, 4-[4-(2-naphthyl)phenyl ]-4',4”-diphenyltriphenylamine (abbreviation: BBAβNBi) was used. The light-emitting element was fabricated in the same manner as in the light-emitting element 9.

[0352] The device structures of the light-emitting elements 9 to 11 are summarized in the table below.

[0353] [Table 19]

[0354] The light-emitting elements 9 to 11 are placed in a glove box with a nitrogen atmosphere. The process of sealing with a glass substrate to prevent exposure to the atmosphere (applying a sealant around the element) After performing UV treatment during sealing and heat treatment at 80°C for 1 hour, the initial characteristics of these light-emitting devices were The measurements were performed at room temperature (25°C). Ta.

[0355] FIG. 49 shows the luminance vs. current density characteristics of the light-emitting elements 9 to 11, and FIG. 49 shows the current efficiency vs. luminance characteristics of the light-emitting elements 9 to 11. Figure 50 shows the brightness-voltage characteristics, Figure 51 shows the current-voltage characteristics, and Figure 52 shows the external quantum efficiency-brightness. The characteristics are shown in FIG. 53 and the emission spectrum in FIG. 54. In addition, the 1000 cd / m 2The main characteristics of the area are shown in Table 20.

[0356] [Table 20]

[0357] 49 to 54 and Table 20, the light-emitting elements 9 to 11 emit blue light with good characteristics. It turned out to be an element.

[0358] In addition, the current value was set to 2 mA, and the change in luminance with respect to the driving time under the condition of a constant current density was A graph showing the results is shown in FIG. 55. As shown in FIG. 55, the light-emitting element which is a light-emitting element of one embodiment of the present invention The light emitting elements 9 to 11 have a small decrease in luminance due to the accumulation of driving time and have a long life. It was found to be.

[0359] In the light-emitting element of this embodiment, the first hole transport material, the second hole transport material, the third hole transport material, the host material The HOMO levels of the luminescent materials are as shown in the table below. The LUMO levels were calculated based on cyclic voltammetry (CV) measurements. The method was the same as in Example 1.

[0360] [Table 21]

[0361] [Table 22]

[0362] [Table 23]

[0363] As shown in the table, in the materials used in the light-emitting elements 9 to 11, the second hole transport material The HOMO level of the first hole transport material is deeper than the HOMO level of the host material. The level is deeper than the HOMO level of the second hole transport material and is lower than the HOMO level of the third hole transport material. The HOMO level of the light-emitting material is deeper than that of the host material. shallower than the HOMO level of

[0364] The HOMO level of the first hole transport material, NPB, is shallow at -5.38 eV, and the L It can easily cause charge separation by interacting with the UMO level of -4.41 eV.

[0365] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and N The HOMO level of PB is 0.31 eV lower than that of the 1,6mMe emitting material. Since the HOMO level of mFLPAPrn is -5.40 eV, the difference is 0.02 eV. Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, Consider a light-emitting device having a structure in which a hole transport layer 112-1 and a light-emitting layer 113 are formed in contact with each other. When the electron injection is performed at a temperature of 1000 ℃, it is considered that the hole injection into the light-emitting material is likely to occur. When holes are injected into the first hole transport layer 112-1, the holes are transported to the boundary between the first hole transport layer 112-1 and the light emitting layer by the light emitting material. In addition, the first holes are trapped at the surface, and the light-emitting region is concentrated, which may accelerate degradation. Since holes are unlikely to enter the host material of the light-emitting layer from the hole transport material of the transport layer 112-1, Holes are accumulated in the hole transport material and electrons are accumulated in the host material. An exciplex with lower energy than the light-emitting material is formed between the transport material and the host material. This may result in problems such as a decrease in luminous efficiency.

[0366] In the light-emitting elements 9 to 11, the second hole-transport layer 112-2 is made of HO rather than a host material. A second hole transport material is used that has a shallow MO level but a deeper HOMO level than the first hole transport material. First, the first hole transport layer 112-1 to the second hole transport layer 112-2 are formed in the above-mentioned manner. The second hole transport material BBAβNB (light-emitting element 9), B The HOMO levels of BAαNB (light-emitting element 10) and BBAβNBi (light-emitting element 11) are respectively − 5.47 eV, -5.49 eV, -5.47 eV, and the first hole transport material NP The difference between A and B is small, 0.09 eV, 0.11 eV, and 0.09 eV, respectively. Holes are smoothly injected from the first hole transport layer 112-1 to the second hole transport layer 112-2. can be.

[0367] Here, let us consider the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113. and between the second hole transport material and the host material, 0.22 eV, 0.20 eV, There is a barrier of about 0.22 eV. Normally, holes are injected without any problems. The HOMO level of the light-emitting material contained in the light-emitting layer 113 is −5.40 eV. There is no barrier for holes to be injected from the transport material to the light-emitting material. Therefore, the holes end up The holes are preferentially injected into the light-emitting material rather than into the host material. As described above, this can lead to problems such as accelerated deterioration and reduced luminous efficiency. stomach.

[0368] Therefore, in the light-emitting elements 9 to 11 which are light-emitting elements according to embodiments of the present invention, Between the transport layer 112-2 and the light-emitting layer 113, a third hole transport layer 112-3 was further provided. The HOM of βNP2PC, which is the third hole transport material contained in the third hole transport layer 112-3 The O level is at -5.79 eV, which is deeper than the host material. Therefore, the second hole transport The hole injection from the material to the third hole transport material without any problem and the hole injection into the host material There is no barrier to the injection of holes into the host material, and the mixing ratio of the host material and the light-emitting material also favors the injection of holes into the host material. In addition, the difference in HOMO level with the second hole transport material is 0.30 eV to 0.32 eV. (within 0.3 eV with one significant digit), and the second hole transport material to the third hole transport material Holes are injected into the MOS transistor without any problems.

[0369] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the region does not concentrate in one part but spreads over the light-emitting layer 113, deterioration is not promoted and light is not emitted. The light-emitting elements 9 to 11 were light-emitting elements having good life spans and luminous efficiency. EXAMPLES

[0370] Example 1 In this example, a light-emitting element 12 according to one embodiment of the present invention described in Embodiment 1 will be described. The structural formula of the organic compound used in the light-emitting element 12 is shown below. [ka]

[0371] (Method of Manufacturing Light-Emitting Element 12) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The first electrode 101 was formed by a deposition method. The area was 2 mm x 2 mm.

[0372] Next, as a pretreatment for forming a light emitting element on the substrate, the substrate surface was washed with water and then dried for 200 After baking at ℃ for 1 hour, UV ozone treatment was performed for 370 seconds.

[0373] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0374] Next, the first electrode 101 is formed so that the surface on which the first electrode 101 is formed faces downward. The substrate was fixed to a substrate holder provided in a vacuum deposition apparatus, and the following was formed on the first electrode 101: The 2, 3, 6, 7, 10, and 11 compounds represented by the above structural formula (i) were prepared by a deposition method using resistance heating. -Hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT —CN) was evaporated to a thickness of 5 nm to form a hole injection layer 111.

[0375] Next, on the hole injection layer 111, 4,4'-bis[N-(1 (N-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) was applied to a film thickness of 10 nm. A first hole transport layer 112-1 is formed by vapor deposition so as to form a first hole transport layer 112-1. to 4-(2-naphthyl)-4',4"-diphenyltrimethylsilyl group represented by the above structural formula (xvi). Phenylamine (abbreviation: BBAβNB) was evaporated to a thickness of 10 nm to form the second hole A transport layer 112-2 is formed, and a hole transport layer represented by the above structural formula (xx) is formed on the second hole transport layer 112-2. 3-[4-(2-naphthyl)phenyl]-9-(2-naphthyl)-9H-carbazol A third hole transport layer 112 was formed by depositing βNPβNC to a thickness of 10 nm. -3 was formed.

[0376] Next, 7-[4-(10-phenyl-9-anthryl) phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) and the above N,N'-bis(3-methylphenyl)-N,N'-bis[3 -(9-phenyl-9H-fluoren-9-yl)phenyl)-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) in a weight ratio of 1:0.03 (=cgDBCz PA: 1,6mMemFLPAPrn) was co-evaporated to form a 25 nm light-emitting layer 113. Formed.

[0377] After that, cgDBCzPA was evaporated onto the light-emitting layer 113 to a thickness of 10 nm, and then Bathophenanthroline (abbreviation: BPhen) represented by the above structural formula (vii) was The electron transport layer 114 was formed by vapor deposition so as to have a thickness of 1 nm.

[0378] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm. The electron injection layer 115 is formed by depositing aluminum to a thickness of 200 nm. The second electrode 102 was formed by vapor deposition to fabricate the light emitting element 12 of this example.

[0379] The device structure of the light-emitting device 12 is summarized in the table below.

[0380] [Table 24]

[0381] The light emitting element 12 is placed in a glove box with a nitrogen atmosphere so that the light emitting element is not exposed to the air. The process of sealing the element with a glass substrate to prevent damage to the element (sealing material is applied around the element and UV is applied during sealing). After performing a thermal treatment at 80°C for 1 hour, the initial characteristics and reliability of these light-emitting devices were The measurements were carried out at room temperature (an atmosphere maintained at 25°C).

[0382] FIG. 56 shows the luminance vs. current density characteristics of the light-emitting element 12, FIG. 57 shows the current efficiency vs. luminance characteristics, and The -voltage characteristics are shown in Figure 58, the current-voltage characteristics in Figure 59, and the external quantum efficiency-luminance characteristics in Figure 60. The emission spectrum is shown in FIG. 2 In the vicinity The main characteristics are shown in Table 25.

[0383] [Table 25]

[0384] 56 to 61 and Table 25, it can be seen that the light-emitting element 12 is a blue light-emitting element with excellent characteristics. I found out.

[0385] In addition, the current value was set to 2 mA, and the change in luminance with respect to the driving time under the condition of a constant current density was A graph showing the results is shown in FIG. 62. As shown in FIG. 62, the light-emitting element which is a light-emitting element of one embodiment of the present invention It was found that the decrease in luminance of element 12 due to the accumulation of driving time was small, and that it was a light-emitting element with a long life. It was.

[0386] In the light-emitting element 12 of this embodiment, the first hole transport material, the third hole transport material, the host The HOMO levels of the materials and the light-emitting materials are as shown in the table below. The LUMO level and the valence potential were calculated based on cyclic voltammetry (CV) measurements. The extraction method is the same as in Example 1.

[0387] [Table 26]

[0388] As shown in the table, in the material used in the light-emitting element 12, the HOMO level of the second hole transport material is deeper than the HOMO level of the first hole transport material, and the HOMO level of the host material is deeper than the HOMO level of the second hole transport material. The HOMO level of the third hole transport material is deeper than that of the host material. The HOMO level of the light-emitting material is deeper than the HOMO level of the host material. Shallower than.

[0389] The HOMO level of the first hole transport material, NPB, is shallow at -5.38 eV, and the L It can easily cause charge separation by interacting with the UMO level of -4.41 eV.

[0390] Here, the HOMO level of the host material cgDBCzPA is -5.69 eV, and N The HOMO level of PB is 0.31 eV lower than that of the 1,6mMe emitting material. Since the HOMO level of mFLPAPrn is -5.40 eV, the difference is 0.02 eV. Since the difference in HOMO level between the light-emitting material and the first hole transport material is small, Consider a light-emitting device having a structure in which a hole transport layer 112-1 and a light-emitting layer 113 are formed in contact with each other. When the electron injection is performed at a temperature of 1000 ℃, it is considered that the hole injection into the light-emitting material is likely to occur. When holes are injected into the first hole transport layer 112-1, the holes are transported to the boundary between the first hole transport layer 112-1 and the light emitting layer by the light emitting material. In addition, the first holes are trapped at the surface, and the light-emitting region is concentrated, which may accelerate degradation. Since holes are unlikely to enter the host material of the light-emitting layer from the hole transport material of the transport layer 112-1, Holes are accumulated in the hole transport material and electrons are accumulated in the host material. An exciplex with lower energy than the light-emitting material is formed between the transport material and the host material. This may result in problems such as a decrease in luminous efficiency.

[0391] In the light-emitting element 12, the second hole transport layer 112-2 is made of a material having a shallower HOMO level than the host material. However, the second hole transport material has a deeper HOMO level than the first hole transport material. As a result, holes are first transported from the first hole transport layer 112-1 to the second hole transport layer 112-2. The HOMO level of the second hole transport material, BBAβNB, is -5.47e V, and the difference between them and the first hole transport material, NPB, is small at 0.09 eV. Therefore, the positive hole can be smoothly transferred from the first hole transport layer 112-1 to the second hole transport layer 112-2. The holes are injected.

[0392] Here, a light-emitting device having a structure in which the second hole transport layer 112-2 and the light-emitting layer 113 are in contact with each other is considered. Considering the case where holes are injected from the second hole transport layer 112-2 to the light emitting layer 113, Between the second hole transport material and the host material, a barrier of about 0.22 eV exists. Normally, holes are injected without any problem, but the light-emitting material contained in the light-emitting layer 113 The HOMO level of the second hole transport material is −5.40 eV, and holes are injected from the second hole transport material to the light emitting material. Therefore, holes end up preferentially entering the emissive material rather than the host material. If holes are injected directly into the light-emitting material, degradation will be accelerated as described above. This can easily cause problems such as the light being cut off or the light emission efficiency decreasing.

[0393] In the light-emitting element 12 which is one embodiment of the present invention, the second hole-transport layer 112-2 A third hole transport layer 112-3 was further provided between the light emitting layer 113. The HOMO level of the third hole transport material, βNPβNC, in layer 112-3 is −5. The electron transport potential of the second hole transport material is 77 eV, which is deeper than that of the host material. In addition, holes are injected from the third hole transport material to the host material without any problem. Since there is no barrier to hole injection into the host material, the mixing ratio of the host material and the light-emitting material also determines the hole injection rate. Since the injection of holes has priority, holes are rarely injected directly into the light-emitting material. The difference in HOMO level between the second hole transport material and the third hole transport material is 0.30 eV ( Within 0.3 eV with one significant digit), and from the second hole transport material to the third hole transport material Holes are injected without any problems.

[0394] Some of the holes injected into the host material are trapped in the light-emitting material, but the appropriate hole trapping is required. In addition, the host material has an electron transporting property. Since it is an anthracene compound, the driving voltage does not increase. Since the region does not concentrate in one part but spreads over the light-emitting layer 113, deterioration is not promoted and light is not emitted. The element 12 became a light-emitting element having a good life and luminous efficiency.

[0395] (Reference example 1) In this reference example, the 4-naphthyl-4′,4″- The synthesis method of diphenyltriphenylamine (abbreviation: BBAβNB) is explained. The structural formula of BAβNB is shown below.

[0396] [ka]

[0397] In a 200 mL three-neck flask, add 2.3 g (7.1 mmol) of bis(4-biphenylyl)acetate. mine, 2.0 g (7.1 mmol) of 2-(4-bromophenyl)naphthalene, and 1. 5 g (15 mmol) of sodium tert-butoxide (abbreviation: tert-BuON a) and 2-dicyclohexylphosphino-2'-6'-dimethoxy-1,1'-biphene After replacing the atmosphere in the flask with nitrogen, 35 mL of xylene was added. The mixture was degassed under reduced pressure, placed under a nitrogen stream, and stirred at 60°C. g (0.20 mmol) of bis(dibenzylideneacetone)palladium(0) was added, The mixture was stirred at 120° C. for 7 hours. After stirring, the mixture was washed with water and saturated saline. The organic layer was washed with magnesium sulfate, and the magnesium sulfate was removed by gravity filtration. The filtrate was concentrated to obtain a brown solid, which was then purified by high performance liquid chromatography (mobile phase: The mixture was purified with chloroform to give 3.5 g of a pale yellow solid, which was the target product, in a yield of 93%. The synthetic scheme for this reaction is shown below.

[0398] [ka]

[0399] The resulting white solid 1 The H NMR is shown below. 1 H NMR (dichloromethane-d2, 500MHz): δ = 7.24 (d, J = 9.0 Hz, 4H), 7.26(d, J=8.5Hz, 2H), 7.31(d, J=7.5Hz , 2H), 7.42(d, J=7.5Hz, 4H), 7.45-7.50(m, 2H), 7.55(d, J=8.5Hz, 4H), 7.60(d, J=7.5Hz, 4H), 7. 68(d, J=8.5Hz, 2H), 7.76(dd, J1=2.0Hz, J2=8.5 Hz, 1H), 7.85(d, J=8.0Hz, 1H), 7.90(t, J=8.05H z, 2H), 8.05(s, 1H)

[0400] Also, 1 The H-NMR chart is shown in Figure 63. Note that Figure 63(B) shows the H-NMR chart of Figure 63(A). This is an expanded chart showing the range of 7.00 ppm to 8.20 ppm. It was found that BBAβNB was obtained through this synthesis reaction.

[0401] The resulting 3.5 g of white solid (BBAβNB) was purified by train sublimation. The conditions for sublimation purification were: pressure 3.4 Pa, argon flow rate 15 mL / min, heating 2 After purification by sublimation, the target pale yellow glassy solid was obtained in an amount of 2.8 g and the recovery rate was 65°C and 16 hours, respectively. I got it at 81%.

[0402] The HOMO and LUMO levels of BBAβNB were measured by cyclic voltammetry (CV). The calculation was based on the measurements and is shown below.

[0403] The measurement device used was an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model). The solution used for CV measurement was dehydrated dimethyl ether as the solvent. Dimethylformamide (DMF) (Aldrich Co., Ltd., 99.8%, Catalog No. 227 05-6) was used as the supporting electrolyte, tetra-n-butylammonium perchlorate (nB u4NClO4) (Tokyo Chemical Industry Co., Ltd., catalog number: T0836) was added at 100 mmol / The measurement target was then dissolved in water to a concentration of 2 mmol / L. The working electrode was a platinum electrode (PT E platinum electrode) as an auxiliary electrode, and a platinum electrode (B.A.S. Co., Ltd., VC-3 P t counter electrode (5 cm)) and Ag / Ag as the reference electrode. + Electrode (B.A.E. The measurements were performed at room temperature (20 to 32°C). The scan speed during CV measurement was standardized to 0.1 V / sec. The oxidation potential Ea [V] and reduction potential Ec [V] of the reference electrode were measured. The intermediate potential of the reduction wave was set as Ec, and the intermediate potential of the reduction-oxidation wave was set as Ec. The potential energy of the reference electrode with respect to the vacuum level is -4.94 eV. Since it is known that the HOMO level [eV] = -4.94-Ea, the LUMO level [eV ]=-4.94-Ec. Calculate the HOMO and LUMO levels. In addition, the measurement was repeated 100 times, and the oxidation- The electrical stability of the compound was examined by comparing the reduction wave with the oxidation-reduction wave of the first cycle.

[0404] As a result, the HOMO level of BBAβNB was found to be -5.47 eV. The UMO level was found to be -2.28 eV. In addition, repeated measurements of the oxidation-reduction wave When comparing the waveforms after the first cycle and 100 cycles, the Ea measurement The peak intensity of BBAβNB was 83% in the Ec measurement and 92% in the Ec measurement. It was confirmed that the resistance to oxidation and reduction was very good.

[0405] Differential scanning calorimetry (DSC) of BBAβNB was performed using a PerkinElmer Py Measured using ris1DSC. Differential scanning calorimetry was performed at a heating rate of 40°C / min. After heating from -10℃ to 300℃, the temperature was kept for 1 minute and then cooled at a rate of 40℃ / min. The DSC measurement results for the second cycle were: The glass transition temperature of BBAβNB was found to be 81°C. The results showed that the melting point was 241°C.

[0406] In addition, thermogravimetry-differential thermal analysis (TG-DTA) of BBAβNB A differential thermal analysis (DTA) was performed. The measurement was performed using a high vacuum differential thermobalance (TG-D, manufactured by Bruker AXS Co., Ltd.). The measurements were performed at atmospheric pressure, with a temperature rise rate of 10°C / min, and nitrogen. The measurement was carried out under air flow (flow rate 200 mL / min). The temperature at which the weight determined by thermogravimetry becomes -5% of the weight at the start of the measurement (decomposition temperature) is 412°C. It was found that the material has high heat resistance.

[0407] (Reference example 2) In this reference example, the 3,6-bis[4-(2-naphthalene) Method for synthesizing β-phenyl-9H-carbazole (abbreviation: βNP2PC) The structural formula of βNP2PC is shown below.

[0408] [ka]

[0409] In a 200 mL three-neck flask, add 1.9 g (4.8 mmol) of 3,6-dibromo-9-phenylenediamine. 2.4 g (9.7 mol) of 4-(2-naphthyl)phenyl boronic acid, 0.12 g (0.40 mmol) of tri(o-tolyl)phosphine, and .7g (19mmol) of potassium carbonate was added. After replacing the atmosphere in the flask with nitrogen, To the mixture was added 40 mL of toluene, 10 mL of ethanol, and 10 mL of water. The mixture was degassed by stirring under reduced pressure. After degassing, 22 mg (0. 10 mmol) of palladium(II) acetate was added. The mixture was heated at 80° C. under a nitrogen stream. After stirring for 4 hours, a solid precipitated. The precipitated solid was collected by suction filtration. The solid was dissolved in about 750 mL of hot toluene, and the solution was separated by filtration through Celite, alumina, and fluoride. The mixture was filtered through Lorisil with suction, and the filtrate was concentrated to obtain a solid, which was washed with toluene. The target product, a white powder, was obtained in 2.6 g with a yield of 99%. The synthesis scheme of this reaction is shown below. .

[0410] [ka]

[0411] The resulting white powder (2.6 g) was purified by train sublimation. The conditions were a pressure of 3.0 Pa, argon gas flow rate of 5.0 mL / min, and a temperature of 350 The white powder was heated at ℃. After purification by sublimation, 2.0g of a white solid was obtained with a recovery rate of 77%.

[0412] The obtained material 1 H NMR was measured, and the measured data is shown below. 1 H NMR(CDCl3,300MHz):δ=7.47-7.55(m,7H),7 .65(s,2H),7.67(d,J=2.4Hz,2H),7.76(dd,J1= 8.4Hz, J2=1.8Hz, 2H), 7.75-7.97(m, 16H), 8.14 (d,J=1.8Hz,2H),8.51(d,J=1.5Hz,2H)

[0413] Also, 1 The H-NMR chart is shown in Figure 64. Note that Figure 64(B) shows the same This is an expanded chart showing the range of 7.20 ppm to 8.60 ppm. It was found that βNP2PC was obtained through this synthetic reaction.

[0414] In addition, thermogravimetry-differential thermal analysis (TG-DTA) of βNP2PC A differential thermal analysis (DTA) was performed. The measurement was performed using a high vacuum differential thermobalance (TG-D, manufactured by Bruker AXS Co., Ltd.). TA2410SA) was used. At normal pressure, temperature rise rate of 10°C / min, nitrogen gas flow (flow rate: 20 0 mL / min), the relationship between weight and temperature (thermogravimetry) showed that βNP The 5% weight loss temperature of 2PC was 500°C or higher. The results showed that the solubility of the solubility-containing

[0415] (Reference example 3) In this reference example, the 4-(1-naphthyl)-4',4"-diphenyl ether used in the light-emitting device 10 The synthesis method of triphenylamine (abbreviation: BBAαNB) is explained. The structural formula is shown below.

[0416] [ka]

[0417] In a 200 mL three-neck flask, add 4.8 g (10 mmol) of 4-bromo-4',4''- Diphenyltriphenylamine and 1.8 g (10 mmol) of 2-naphthylboronic acid , 0.31 g (1.0 mmol) of tris(2-methylphenyl)phosphine and 40 m L of toluene, 10 mL of ethanol, and 10 mL of aqueous potassium carbonate (2.0 mo The flask was then degassed by stirring while reducing the pressure inside the flask. After degassing, The mixture was placed under a nitrogen stream and heated to 60°C. After heating, 0.12 g (0.5 m mol) palladium(II) acetate was added and the mixture was stirred at 80° C. for 1.5 h. After stirring, the mixture was allowed to cool to room temperature, and the organic layer was washed with water. The extract and the organic layer were combined and washed with saturated saline, then magnesium sulfate was added. The mixture was gravity filtered and the filtrate was concentrated to obtain a brown solid. The solid was dissolved in chloroform, and the solution was subjected to high performance liquid chromatography. (Japan Analytical Industry Co., Ltd. Recycled Preparative HPLC LC-SakuraNEXT, Mobile phase: The product was purified with chloroform to give 3.9 g of a white solid in 75% yield. The synthetic scheme for this reaction is shown below.

[0418] [ka]

[0419] The pale yellow solid obtained 1 H NMR was measured and the data is shown below. 1 H NMR (dichloromethane-d2, 500 MHz): δ = 7.26-7.29 (m, 6H), 7.31(t, J=7.0Hz, 2H), 7.41-7.54(m, 10H), 7.56(d, J=8.5Hz, 4H), 7.60(d, J=7.0Hz, 4H), 7. 84(d, J=8.0Hz, 1H), 7.90(d, J=7.0Hz, 1H), 8.03 (d, J=9.0Hz, 1H)

[0420] Also, 1 The H-NMR chart is shown in Figure 65. Note that Figure 65(B) shows the H-NMR chart of Figure 65(A). This is a chart showing an expanded range of 7.0 ppm to 8.5 ppm. It was found that BBAαNB was obtained in this synthesis.

[0421] The resulting solid (3.9 g) (BBAαNB) was purified by train sublimation. The sublimation purification was carried out under a pressure of 3.4 Pa with argon flowing at a rate of 15 mL / min. The solid was heated at 250°C for 16 hours, and 2.4 g of the target solid was obtained. , with a recovery rate of 62%.

[0422] The HOMO and LUMO levels of BBAαNB were measured by cyclic voltammetry (CV). The calculation was based on the measurements and is shown below.

[0423] The measurement device used was an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model). The solution used in the CV measurements was dehydrated dimethyl ether. Dimethylformamide (DMF) (Aldrich Co., Ltd., 99.8%, Catalog No. 227 05-6) was used as the supporting electrolyte, tetra-n-butylammonium perchlorate (nB u4NClO4) (Tokyo Chemical Industry Co., Ltd., catalog number: T0836) was added at 100 mmol / The measurement target was then dissolved in water to a concentration of 2 mmol / L. The working electrode was a platinum electrode (PT E platinum electrode) as an auxiliary electrode, and a platinum electrode (B.A.S. Co., Ltd., VC-3 P t counter electrode (5 cm)) and Ag / Ag as the reference electrode. + Electrode (B.A.E. The measurements were performed at room temperature (20 to 32°C). The scan speed during CV measurement was standardized to 0.1 V / sec. The oxidation potential Ea [V] and reduction potential Ec [V] of the reference electrode were measured. The intermediate potential of the reduction wave was set as Ec, and the intermediate potential of the reduction-oxidation wave was set as Ec. The potential energy of the reference electrode with respect to the vacuum level is -4.94 eV. Since it is known that the HOMO level [eV] = -4.94-Ea, the LUMO level [eV ]=-4.94-Ec. Calculate the HOMO and LUMO levels. In addition, CV measurements were performed 100 times, and the acid in the 100th cycle was The electrical stability of the compound was examined by comparing the oxidation-reduction wave of the first cycle with the oxidation-reduction wave of the second cycle. .

[0424] As a result, the HOMO level of BBAαNB was −5.4 9 eV, while the LUMO level was found to be -2.24 eV. In addition, in repeated measurements of the oxidation-reduction wave, the waveforms after the first cycle and the 100th cycle were In comparison, the peak intensity was 93% in the Ea measurement and 92% in the Ec measurement. This indicates that BBAαNB has excellent resistance to oxidation and reduction. It was confirmed that:

[0425] Differential scanning calorimetry (DSC) of BBAαNB was performed using a PerkinElmer Py Measured using ris1DSC. Differential scanning calorimetry was performed at a heating rate of 40°C / min. After heating from -10℃ to 270℃, hold at that temperature for 1 minute, then cool at a rate of 40℃ / m The operation of cooling to -10℃ at 100℃ was performed twice in succession, and the second measurement result was used. C measurement revealed that the glass transition temperature of BBAαNB was 84°C.

[0426] (Reference example 4) In this reference example, the 4-[4-(2-naphthyl)phenyl]-4′,4 This article explains the synthesis method of β-diphenyltriphenylamine (abbreviation: BBAβNBi). The structure of BBAβNBi is shown below.

[0427] [ka]

[0428] In a 200 mL three-neck flask, add 4.8 g (10 mmol) of 4-bromo-4',4''- Diphenyltriphenylamine and 2.5 g (10 mmol) of 4-(2-naphthyl)phenyl phenylboronic acid and 0.31 g (0.50 mmol) of tris(2-methylphenyl)boronic acid. Sulfur, 40 mL of toluene, 10 mL of ethanol, and 10 mL of potassium carbonate An aqueous solution (2.0 mol / L) was added, and the mixture was stirred while reducing the pressure inside the flask. After degassing, the system was purged with a nitrogen gas stream, and the mixture was heated to 60°C. 0.11 g (0.5 mmol) of palladium(II) acetate was added and the mixture was heated at 80° C. for 1 The mixture was stirred for 1.5 hours. After stirring, the mixture was allowed to cool to room temperature, and the precipitated solid was collected by suction filtration. The solid was washed with toluene, ethanol, and water. The solid was collected by suction filtration to give 2.9 g of a brown solid, the product of interest, in a yield of 49%. The reaction scheme of the synthesis reaction is shown below.

[0429] [ka]

[0430] The pale yellow solid obtained 1 1 H NMR was measured and the data is shown below. 1 H NMR (dichloromethane-d2, 500MHz, 500MHz): δ = 7.22- 7.25(m, 6H), 7.31(t, J=7.3Hz, 2H), 7.42(t, J=7 .8Hz,4H), 7.46-7.52(m, 2H), 7.55(d, J=7.5Hz, 4H), 7.59-7.63(m, 6H), 7.74(d, J=8.0Hz, 2H), 7 .18-7.83(m, 3H), 7.87(d, J=7.5Hz, 1H), 7.93(t , J=8.7, 2H), 8.11(s, 1H)

[0431] Also, 1 The H-NMR chart is shown in Figure 66. Note that Figure 66(B) shows the H-NMR chart of Figure 66(A). This is a chart showing an expanded range of 7.0 ppm to 8.3 ppm. It was found that BBAβNBi was obtained by this synthetic reaction.

[0432] The resulting solid (2.9 g) (BBAβNBi) was purified by train sublimation. The sublimation purification was carried out under a pressure of 4.0 Pa with argon flowing at a rate of 15 mL / min. The solid was then heated at 300°C for 16 hours, and the target white solid was isolated in 1 .9g, with a recovery rate of 65%

[0433] The HOMO and LUMO levels of BBAβNBi were measured by cyclic voltammetry (CV The calculation method was the same as in Reference Example 3.

[0434] As a result, in measuring the oxidation potential Ea [V] of BBAβNBi, the HOMO level was found to be -5. The LUMO level was found to be 47 eV, while the LUMO level was found to be -2.38 eV. In addition, in the repeated measurement of the oxidation-reduction wave, the waveforms after the first cycle and the 100th cycle In comparison, the peak intensity was 82% in the Ea measurement and 67% in the Ec measurement. This indicates that BBAβNBi has excellent resistance to oxidation and reduction. It was confirmed that.

[0435] Differential scanning calorimetry (DSC) of BBAβNBi was performed using a PerkinElmer Measured using yris1DSC. Differential scanning calorimetry was performed at a heating rate of 40°C / min. After heating from -10℃ to 270℃, the sample was kept at the same temperature for 1 minute and cooled at a rate of 40℃ / min. The operation of cooling to -10℃ at 100℃ was performed twice in succession, and the second measurement result was used. From the C measurement, it was found that the glass transition temperature of BBAβNBi is 97℃, which shows good heat resistance. It was revealed that the compound has the following structure:

[0436] (Reference example 5) In this reference example, the 3-[4-(2-naphthyl)phenyl]-9-(2 This article describes the synthesis method of β-naphthyl-9H-carbazole (abbreviation: βNPβNC). The structural formula of NPβNC is shown below.

[0437] [ka]

[0438] In a 200 mL three-neck flask, add 2.3 g (8.1 mmol) of 2-(4-bromophenyl) Naphthalene and 3.4 g (8.1 mol) of 4,4,5,5-tetramethyl-2-[9- (2-naphthyl)-9H-carbazol-3-yl]-1,3,2-dioxaborolane , 50 mg (0.16 mmol) of tri(o-tolyl)phosphine and 2.2 g (16 mmol) of The flask was replaced with nitrogen, and 30 ml of potassium carbonate was added to the mixture. L of toluene, 10 mL of ethanol, and 8.0 mL of water were added. The mixture was heated under reduced pressure. After degassing, 18 mg (0.081 mmol) of water was added to the mixture. l) Palladium(II) acetate was added. The mixture was stirred at 80°C for 4 hours under a nitrogen stream. The precipitated solid was collected by suction filtration. The aqueous layer of the filtrate was The extract was combined with the organic layer and washed with saturated saline. The mixture was dried over magnesium and gravity filtered. The filtrate was concentrated to give a solid. The collected solid was dissolved in about 200 mL of hot toluene, and the solution was filtered through Celite (Wako Junyaku Kogyo Co., Ltd., Catalog Number: 537-02305), Alumina, Florisil (Japanese The mixture was filtered through a suction filter (Hikari Pure Chemical Industries, Ltd., catalog number: 066-05265). The filtrate was concentrated and the solid obtained was recrystallized with toluene, yielding 2.9g of the desired white powder. The reaction scheme of the synthesis reaction is shown below.

[0439] [ka]

[0440] The resulting white powder (2.9 g) was purified by train sublimation. The conditions were a pressure of 3.9 Pa, argon gas flow rate of 5.0 mL / min, and 280 The white powder was heated at 50°C. After purification by sublimation, 2.1 g of white solid βNPβNC was obtained, with a recovery rate of 72%. Obtained in %.

[0441] The obtained material 1 H NMR was measured, and the measured data is shown below. 1 H NMR(CDCl3,300MHz):δ=7.35(ddd,J1=6.6Hz ,J2=1.2Hz,1H),7.42-7.63(m,5H),7.60(dd,J1 =9.6Hz,J2=6.3Hz,2H),7.69-7.76(m,2H),7.82 -8.01(m,10H),8.08-8.13(m,3H),8.25(d,J=7. 8Hz,1H),8.46(d,J=1.5Hz,1H)

[0442] Also, 1 The H-NMR chart is shown in Figure 67. Note that Figure 67(B) shows the H-NMR chart of Figure 67(A). This is a chart showing an expanded range of 7.20 ppm to 8.60 ppm. It was found that βNPβNC was obtained through this synthetic reaction.

[0443] In addition, thermogravimetry-differential thermal analysis (TG-DTA) of βNPβNC was performed. A differential thermal analysis (DTA) was performed. The measurement was performed using a high vacuum differential thermobalance (TG-D, manufactured by Bruker AXS Co., Ltd.). TA2410SA) was used. At normal pressure, temperature rise rate of 10°C / min, nitrogen gas flow (flow rate: 20 0 mL / min), the relationship between weight and temperature (thermogravimetry) showed that βNP The 5% weight loss temperature of βNC was 431°C. This indicates that βNPβNC has high heat resistance. It was shown to be good. [Explanation of symbols]

[0444] 101 First electrode 102 Second electrode 103 EL layer 111 Hole injection layer 112-1 First hole transport layer 112-2 Second hole transport layer 112-3 Third hole transport layer 113 Light-emitting layer 114 Electron transport layer 115 Electron injection layer 116 Charge generation layer 117 P type layer 118 Electronic Relay Layer 119 Electron injection buffer layer 400 Substrates 401 First electrode 403 EL layer 404 Second electrode 405 Sealing material 406 Sealing material 407 Sealing substrate 412 Pad 420 IC chip 501 First electrode 502 Second electrode 511 First Light Emitting Unit 512 Second Light Emitting Unit 513 Charge generation layer 601 Driver circuit section (source line driver circuit) 602 Pixel section 603 Drive circuit section (gate line drive circuit) 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 Element Substrate 611 Switching FET 612 Current Control FET 613 First electrode 614 Insulation 616 EL layer 617 Second Electrode 618 Light-emitting element 901 Case 902 Liquid crystal layer 903 Backlight unit 904 Case 905 Driver IC 906 Terminal 951 Board 952 Electrode 953 Insulation Layer 954 Partition layer 955 EL layer 956 Electrode 1001 Board 1002 Undercoat insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 Electrode 1024W First electrode 1024R First electrode 1024G First electrode 1024B First electrode 1025 Bulkhead 1028 EL layer 1029 Second electrode 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red color 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 Periphery 2001 Case 2002 light source 3001 Lighting equipment 5000 display area 5001 Display area 5002 Display area 5003 Display area 5004 Display area 5005 Display area 7101 Case 7103 Display section 7105 Stand 7107 Display section 7109 Operation key 7110 Remote control device 7201 Main unit 7202 Case 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing Device 7210 Second display unit 7301 Case 7302 Case 7303 Connection section 7304 Display section 7305 Display section 7306 Speaker section 7307 Recording medium insertion section 7308 LED Lamp 7309 Operation key 7310 Connection terminal 7311 Sensor 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 7400 Mobile Phone 9033 Fastener 9034 Switch 9035 Power Switch 9036 Switch 9038 Operation switch 9310 Mobile Information Terminal 9311 Display Panel 9312 Display area 9313 Hinge 9315 Case 9630 Case 9631 Display section 9631a Display section 9631b Display section 9632a Touch Panel Area 9632b Touch panel area 9633 Solar Cells 9634 Charge / discharge control circuit 9635 Battery 9636 DC-DC Converter 9637 Operation key 9638 Converter 9639 Button

Claims

1. A semiconductor device comprising a first electrode, a second electrode, a hole injection layer between the first electrode and the second electrode, a first layer, a second layer, a third layer, and a fourth layer; the hole injection layer is located between the first electrode and the first layer; the first layer is located between the hole injection layer and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the fourth layer; the fourth layer is located between the third layer and the second electrode; the first layer comprises a first organic compound; the second layer includes a second organic compound having a triphenylamine skeleton not condensed with a phenyl group; the third layer includes a third organic compound having a carbazole skeleton, the fourth layer comprises a host material and a light-emitting material; the HOMO level of the second organic compound is deeper than the HOMO level of the first organic compound; a HOMO level of the host material is deeper than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the second organic compound and a HOMO level of the third organic compound is 0.3 eV or less.

2. A semiconductor device comprising a first electrode, a second electrode, a hole injection layer between the first electrode and the second electrode, a first layer, a second layer, a third layer, and a fourth layer; the hole injection layer is located between the first electrode and the first layer; the first layer is located between the hole injection layer and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the fourth layer; the fourth layer is located between the third layer and the second electrode; the first layer includes a first organic compound having a triphenylamine skeleton; the second layer includes a second organic compound having a triphenylamine skeleton not condensed with a phenyl group; the third layer includes a third organic compound having a carbazole skeleton, the fourth layer comprises a host material and a light-emitting material; the HOMO level of the second organic compound is deeper than the HOMO level of the first organic compound; a HOMO level of the host material is deeper than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the second organic compound and a HOMO level of the third organic compound is 0.3 eV or less.

3. A semiconductor device comprising: a first electrode; a second electrode; a hole injection layer between the first electrode and the second electrode; a first layer, a second layer, a third layer, and a fourth layer; the hole injection layer is located between the first electrode and the first layer; the first layer is located between the hole injection layer and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the fourth layer; the fourth layer is located between the third layer and the second electrode; the first layer comprises a first organic compound; the second layer includes a second organic compound having a triphenylamine skeleton not condensed with a phenyl group; the third layer includes a third organic compound having a carbazole skeleton, the fourth layer comprises a host material and a light-emitting material; the hole injection layer comprises a fourth organic compound having at least one of a halogen group and a cyano group, the HOMO level of the second organic compound is deeper than the HOMO level of the first organic compound; a HOMO level of the host material is deeper than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the second organic compound and a HOMO level of the third organic compound is 0.3 eV or less.

4. A semiconductor device comprising: a first electrode; a second electrode; a hole injection layer between the first electrode and the second electrode; a first layer, a second layer, a third layer, and a fourth layer; the hole injection layer is located between the first electrode and the first layer; the first layer is located between the hole injection layer and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the fourth layer; the fourth layer is located between the third layer and the second electrode; the first layer includes a first organic compound having a triphenylamine skeleton; the second layer includes a second organic compound having a triphenylamine skeleton not condensed with a phenyl group; the third layer includes a third organic compound having a carbazole skeleton, the fourth layer comprises a host material and a light-emitting material; the hole injection layer comprises a fourth organic compound having at least one of a halogen group and a cyano group, the HOMO level of the second organic compound is deeper than the HOMO level of the first organic compound; a HOMO level of the host material is deeper than a HOMO level of the second organic compound; A light-emitting element, wherein a difference between a HOMO level of the second organic compound and a HOMO level of the third organic compound is 0.3 eV or less.

5. In any one of claims 1 to 4, The light-emitting element has a HOMO level of the first organic compound of -5.4 eV or higher.

6. In any one of claims 1 to 5, A light-emitting element, wherein a difference between a HOMO level of the first organic compound and a HOMO level of the second organic compound is 0.3 eV or less.

7. In any one of claims 1 to 6, A light-emitting device in which the HOMO level of the light-emitting material is shallower than the HOMO level of the host material.

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