Light-emitting device, electronic device and lighting device

Abstract

To provide a light-emitting apparatus with low consumption power.SOLUTION: A light-emitting apparatus includes a first light-emitting device and a first color conversion layer. The first light-emitting device includes an anode, a cathode, and an EL layer existing between the anode and the cathode. The EL layer includes a layer containing a material whose refractive index to the light with a wavelength of 467 nm is 1.75 or less. The first color conversion layer includes a first substance absorbing light and emitting light. The light emitted from the first light-emitting device is delivered to the first color conversion layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to an organic compound, a light-emitting element, a light-emitting device, a display module, a lighting module, a display device, a light-emitting device, an electronic device, a lighting device, and an electronic device. Note that an embodiment of the present invention is not limited to the above technical field. A technical field of an embodiment of the present invention disclosed in the present specification and the like relates to an object, a method, or a manufacturing method. Alternatively, an embodiment of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of an embodiment of the present invention disclosed in the present specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a storage device, an imaging device, a driving method thereof, or a manufacturing method thereof. [Background technology]

[0002] Light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds are becoming more and more practical. The basic structure of these light-emitting devices is a pair of electrodes sandwiching an organic compound layer (EL layer) containing a light-emitting material between them. By applying a voltage to this device, carriers are injected, and the recombination energy of the carriers is utilized to emit light from the light-emitting material.

[0003] Since such light-emitting devices are self-luminous, when used as display pixels, they have advantages such as high visibility and no need for backlighting compared to liquid crystals, making them suitable as elements for flat panel displays. Another major advantage of displays using such light-emitting devices is that they can be made thin and lightweight. Another characteristic is that they have an extremely fast response speed.

[0004] In addition, these light-emitting devices can have light-emitting layers formed continuously in two dimensions, making it possible to obtain surface-like light emission. This is a feature that is difficult to obtain with point light sources such as incandescent light bulbs and LEDs, or linear light sources such as fluorescent lamps, making them highly valuable as surface light sources for lighting and other applications.

[0005] Displays and lighting devices using such light-emitting devices are suitable for use in a variety of electronic devices, but research and development is ongoing to find light-emitting devices with even better characteristics.

[0006] One of the problems that is often cited when discussing organic EL devices is their low light extraction efficiency. In particular, attenuation due to reflection caused by differences in the refractive index of adjacent layers is a major factor in reducing the efficiency of the device. In order to reduce this effect, a structure has been proposed in which a layer made of a low refractive index material is formed inside the EL layer (see, for example, Patent Document 1 and Non-Patent Document 1).

[0007] A light-emitting device having this configuration can have a higher light extraction efficiency and therefore a higher external quantum efficiency than a light-emitting device having a conventional configuration, but it is not easy to form such a low refractive index layer inside the EL layer without adversely affecting other important properties of the light-emitting device. This is because there is a trade-off between a low refractive index and high carrier transportability or reliability when used in a light-emitting device. This problem is caused by the fact that the carrier transportability and reliability of organic compounds are largely derived from the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have a high refractive index.

[0008] On the other hand, displays using a color conversion method have been put to practical use. The color conversion method is a method in which light from a light-emitting device is irradiated onto a photoluminescent material to convert it into light of a desired color. Compared to color filter displays that simply cut the light from a light-emitting device, color conversion displays have the advantage that, although it depends on the efficiency of photoluminescence, they have less energy loss and it is easier to obtain displays with low power consumption. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2014-207356 A [Non-Patent Document 1] Jaeho Lee and 12 others, "Synergetic electrode architecture for efficient graphene-based flexible organic light-emitting diodes", Nature COMMUNICATIONS, June 2, 2016, DOI:10.1038 / ncomms11791 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 device, to provide a light-emitting device with high emission efficiency, to provide a light-emitting device with a long lifetime, or to provide a light-emitting device with a low driving voltage.

[0011] Another object of another embodiment of the present invention is to provide an electronic device or a display device with high reliability, or an electronic device or a display device with low power consumption.

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

[0013] One aspect of the present invention is a light-emitting device having a first light-emitting device and a first color conversion layer, the first light-emitting device having an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer having a layer containing a material having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer including a first substance that absorbs light and emits light, and light emitted from the first light-emitting device is irradiated onto the first color conversion layer.

[0014] Another aspect of the present invention is a light-emitting device having a first light-emitting device and a first color conversion layer, wherein the first light-emitting device has an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer has a layer having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer includes a first substance that absorbs light and emits light, and light emitted from the first light-emitting device is irradiated onto the first color conversion layer.

[0015] Alternatively, another embodiment of the present invention is a light-emitting device having a first light-emitting device and a first color conversion layer, the first light-emitting device having an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer having a light-emitting layer and a hole injection layer, the hole injection layer being provided in contact with the anode, the hole injection layer containing an organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer containing a first substance that absorbs light and emits light, and the light emitted from the first light-emitting device is irradiated to the first color conversion layer.

[0016] Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned configuration, wherein the organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm is a monoamine compound having a first aromatic ring, a second aromatic ring, and a third aromatic ring, the first aromatic ring, the second aromatic ring, and the third aromatic ring are bonded to nitrogen atoms of the monoamine compound, and a ratio of carbons forming bonds through sp3 hybrid orbitals to the total number of carbons in the molecule is 23% or more and 55% or less.

[0017] Another embodiment of the present invention is a light-emitting device having the above structure, in which the organic compound having a refractive index of 1.75 or less with respect to light having a wavelength of 467 nm is an organic compound represented by the following general formula (G1):

[0018] [ka]

[0019] In the above general formula (G1), Ar 1 , Ar 2 each independently represents a benzene ring or a substituent in which two or three benzene rings are bonded to each other, provided that Ar 1 , Ar 2 one or both of the carbon atoms have one or more hydrocarbon groups having 1 to 12 carbon atoms, the carbon atoms forming bonds only through sp3 hybrid orbitals, and Ar 1 and Ar 2 The total number of carbon atoms contained in the hydrocarbon group bonded to Ar is 8 or more, and 1 and Ar 2 The total number of carbon atoms contained in the hydrocarbon group bonded to at least one of Ar 1 or Ar 2 When a plurality of linear alkyl groups having 1 or 2 carbon atoms are bonded to R as the hydrocarbon group, the linear alkyl groups may be bonded to each other to form a ring. 1 and R 2 Each independently represents an alkyl group having 1 to 4 carbon atoms. 1 and R2 may be bonded to each other to form a ring. 3 represents an alkyl group having 1 to 4 carbon atoms; and u is an integer of 0 to 4.

[0020] Alternatively, another aspect of the present invention is a light-emitting apparatus having a first light-emitting device and a first color conversion layer, the first light-emitting device having an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer having a light-emitting layer and an electron transport layer, the electron transport layer being located between the light-emitting layer and the cathode, the electron transport layer having a material having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer including a first substance that absorbs light and emits light, and light emitted from the first light-emitting device is irradiated to the first color conversion layer.

[0021] Another embodiment of the present invention is a light-emitting device having the above structure, in which the material having a refractive index of 1.75 or less is a mixed material of an organic compound having an electron-transporting property and an inorganic compound, and the inorganic compound is an alkali metal fluoride or an alkaline earth metal fluoride.

[0022] Another embodiment of the present invention is a light-emitting device having the above structure, in which the inorganic compound is an alkali metal, and the concentration of the inorganic compound in the electron transport layer is 50 vol % or more.

[0023] Another embodiment of the present invention is a light-emitting device having the above structure, in which the inorganic compound is an alkali metal, and the concentration of the inorganic compound in the electron-transporting layer is greater than or equal to 50 vol % and less than 95 vol %.

[0024] Another embodiment of the present invention is a light-emitting device having the above structure, in which the concentration of the inorganic compound in the electron transport layer is 20 vol % or more.

[0025] Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned configuration, a first light-emitting device and a first color conversion layer, wherein the first light-emitting device has an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer has a hole injection layer, a light-emitting layer, and an electron transport layer, the hole injection layer is located between the anode and the light-emitting layer, the electron transport layer is located between the light-emitting layer and the cathode, the hole injection layer has an organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the electron transport layer has a material having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer has a first substance that absorbs light and emits light, and the first color conversion layer is irradiated with light emitted from the first light-emitting device.

[0026] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the peak wavelength of an emission spectrum obtained from the first light-emitting device is in the range of 440 nm to 520 nm.

[0027] Alternatively, another aspect of the present invention is a light-emitting apparatus having a first light-emitting device and a first color conversion layer, the first light-emitting device having an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer having a hole injection layer, a light-emitting layer, and an electron transport layer, the hole injection layer being located between the anode and the light-emitting layer, the electron transport layer being located between the light-emitting layer and the cathode, the hole injection layer having an organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the electron transport layer having a material having a refractive index of 1.75 or less for light with a wavelength of 467 nm, the first color conversion layer having a first substance that absorbs light and emits light, and the light emitted from the first light-emitting device is irradiated to the first color conversion layer.

[0028] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first substance is a quantum dot.

[0029] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the first light-emitting device has a microresonator structure.

[0030] Alternatively, another embodiment of the present invention is a light-emitting device having the above configuration, further comprising a second light-emitting device, a third light-emitting device, and a second color conversion layer, wherein the second light-emitting device and the third light-emitting device have the same structure as the first light-emitting device, the second color conversion layer comprises a second substance that absorbs light and emits light, the peak wavelength of the emission spectrum of the first substance is different from the peak wavelength of the emission spectrum of the second substance, and the light emitted from the second light-emitting device is irradiated to the second color conversion layer.

[0031] Another embodiment of the present invention is a light-emitting device having the above structure, in which the second substance is a quantum dot.

[0032] Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned structure, in which the first substance has an emission spectrum having a peak wavelength in the range of 500 nm to 600 nm, and the second substance has an emission spectrum having a peak wavelength in the range of 600 nm to 750 nm.

[0033] Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned configuration, further comprising a fourth light-emitting device and a third color conversion layer, the fourth light-emitting device having the same structure as the first light-emitting device, the third color conversion layer having a third substance that absorbs light and emits light, the third substance having an emission spectrum with a peak wavelength between 560 nm and 610 nm, and the light emitted from the fourth light-emitting device being irradiated to the third color conversion layer.

[0034] Another embodiment of the present invention is a light-emitting device having the above structure, in which the third substance contains a rare earth element.

[0035] Another embodiment of the present invention is a light-emitting device having the above structure, in which the rare earth element is at least one of europium, cerium, and yttrium.

[0036] Another embodiment of the present invention is a light-emitting device having the above structure, in which the third substance is a quantum dot.

[0037] Another embodiment of the present invention is a light-emitting device having the above structure, in which an emission spectrum obtained from the third color conversion layer has two peaks.

[0038] Another embodiment of the present invention is a light-emitting device having the above structure, in which the third color conversion layer emits white light.

[0039] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting device has a plurality of light-emitting layers.

[0040] Another embodiment of the present invention is a light-emitting device having the above structure, further including a charge generation layer between the plurality of light-emitting layers.

[0041] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first light-emitting device emits blue light.

[0042] Alternatively, in another aspect of the present invention, in the above-mentioned configuration, the light-emitting device has a color filter, and the first color conversion layer is located between the first light-emitting device and the color filter.

[0043] Another embodiment of the present invention is an electronic device including any of the above light-emitting devices and a sensor, an operation button, a speaker, or a microphone.

[0044] Another embodiment of the present invention is a light-emitting device including any of the above light-emitting devices and a transistor or a substrate.

[0045] Another embodiment of the present invention is a lighting device including any of the above light-emitting devices and a housing.

[0046] In this specification, the term "light-emitting device" includes an image display device using a light-emitting device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or TCP (Tape Carrier Package), is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (integrated circuit) is directly mounted on a light-emitting device by a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may have a light-emitting device. Effect of the Invention

[0047] According to one embodiment of the present invention, a novel light-emitting device having high emission efficiency, a light-emitting device having a long lifetime, or a light-emitting device with low driving voltage can be provided.

[0048] According to another embodiment of the present invention, it is possible to provide an electronic device or a display device with high reliability, or an electronic device or a display device with low power consumption.

[0049] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract effects other than these from the description in the specification, drawings, claims, etc. [Brief description of the drawings]

[0050] [Figure 1] 1(A), (B), and (C) are conceptual diagrams of a light-emitting device. [Diagram 2] 2(A), (B), and (C) are schematic diagrams of light-emitting devices. [Diagram 3] FIG. 3 is a schematic diagram of a light emitting device. [Figure 4] 4(A), (B), and (C) are conceptual diagrams of a light-emitting device. [Diagram 5] 5(A), (B), and (C) are conceptual diagrams of a light-emitting device. [Figure 6] 6(A) and (B) are conceptual diagrams of a passive matrix type light emitting device. [Figure 7] 7(A) and (B) are conceptual diagrams of an active matrix type light emitting device. [Figure 8] 8(A) and (B) are conceptual diagrams of an active matrix type light emitting device. [Figure 9] FIG. 9 is a conceptual diagram of an active matrix type light emitting device. [Figure 10] 10(A), (B1), (B2), and (C) are diagrams showing electronic devices. [Figure 11] 11(A), (B), and (C) are diagrams showing electronic devices. [Figure 12] FIG. 12 is a diagram showing an in-vehicle display device and a lighting device. [Figure 13] 13(A) and (B) are diagrams showing electronic devices. [Figure 14] 14(A), (B), and (C) are diagrams showing electronic devices. [Figure 15] FIG. 15 shows data obtained by measuring the refractive index of dchPAF. [Figure 16] FIG. 16 shows the data obtained by measuring the refractive index of chBichPAF. [Figure 17] FIG. 17 shows data obtained by measuring the refractive index of dchPASchF. [Figure 18] FIG. 18 shows data obtained by measuring the refractive index of chBichPASchF. [Figure 19] FIG. 19 shows data obtained by measuring the refractive index of SchFB1chP. [Figure 20] FIG. 20 shows the data obtained by measuring the refractive index of mmtBuBichPAF. [Figure 21]FIG. 21 shows data obtained by measuring the refractive index of dmmtBuBiAF. [Figure 22] FIG. 22 shows data obtained by measuring the refractive index of mmtBuBimmtBuPAF. [Diagram 23] FIG. 23 shows data obtained by measuring the refractive index of dchPAPrF. [Figure 24] FIG. 24 shows data obtained by measuring the refractive index of mmchBichPAF. [Diagram 25] FIG. 25 shows data obtained by measuring the refractive index of mmtBumTPchPAF. [Figure 26] FIG. 26 shows data obtained by measuring the refractive index of CdoPchPAF. [Figure 27] FIG. 27 shows the emission spectrum used in the calculation. [Figure 28] FIG. 28 is a diagram showing the results of calculating the relationship between the refractive index of the color conversion layer (QD layer) and the amount of light that reaches the color conversion layer. [Figure 29] FIG. 29 is a graph showing the luminance-current density characteristics of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. [Diagram 30] FIG. 30 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. [Diagram 31] FIG. 31 is a diagram showing the luminance-voltage characteristics of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. [Diagram 32] FIG. 32 is a diagram showing the current-voltage characteristics of the light-emitting device 1 and the light-emitting device 2. In FIG. [Diagram 33] FIG. 33 is a graph showing the blue index-luminance characteristics of the light-emitting device 1 and the light-emitting device 2. In FIG. [Diagram 34] FIG. 34 shows the emission spectra of the light-emitting device 1 and the light-emitting device 2. As shown in FIG. [Diagram 35] FIG. 35 shows the refractive indices of dchPAF and PCBBiF. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0052] (Embodiment 1) In recent years, color conversion technology using quantum dots (QDs) has been put to practical use in fields such as liquid crystal displays. QDs are semiconductor nanocrystals with a size of a few nm, and the number of QDs is about 1×10 3 1×10 6 QDs are composed of about 10 ...

[0053] In addition, QDs have a narrow emission spectrum peak width because their discrete nature limits phase relaxation, making it possible to obtain light emission with good color purity. In other words, by using a color conversion layer that uses QDs, it is possible to obtain light emission with high color purity, and it is also possible to obtain light emission that covers Rec.2020, a color gamut standardized in the BT.2020 and BT.2100 standards.

[0054] Like color conversion layers using organic light-emitting materials, color conversion layers using QDs absorb light emitted from a light-emitting device and re-emit it, converting the light into light with longer wavelengths. Therefore, when using color conversion layers for displays, a configuration is adopted in which blue light, which has the shortest wavelength of the three primary colors required to reproduce full color, is obtained from the light-emitting device, and green and red light are obtained by color conversion.

[0055] That is, in a display employing a color conversion method, the characteristics of the blue light-emitting device used will determine many of the characteristics, and as a result, there is a demand for blue light-emitting devices with better characteristics.

[0056] 1A, a light-emitting device according to one embodiment of the present invention includes a pixel 208 having a light-emitting device 207 and a color conversion layer 205, and light emitted from the light-emitting device 207 is incident on the color conversion layer 205. The light-emitting device 207 includes an EL layer 202 between a first electrode 201 and a second electrode 203. The color conversion layer 205 preferably includes quantum dots and has a function of absorbing incident light and emitting light of a predetermined wavelength. When the color conversion layer 205 includes quantum dots, light emission with a narrow peak width in the emission spectrum and good color purity can be obtained.

[0057] The color conversion layer 205 contains a substance that absorbs incident light and emits light of a predetermined wavelength, and various light-emitting substances such as inorganic materials exhibiting photoluminescence and organic materials can be used as the substance that emits light of a predetermined wavelength. In particular, quantum dots (QDs), which are inorganic materials, have a narrow peak width of the emission spectrum as described above, and can emit light with good color purity. In addition, they are preferable because they are inorganic materials, have excellent intrinsic stability, and have a theoretical internal quantum efficiency of almost 100%.

[0058] The color conversion layer 205 containing quantum dots can be formed by applying a solvent in which quantum dots are dispersed, drying, and baking. Sheets in which quantum dots are already dispersed have also been developed. Colors can be applied separately by droplet ejection methods such as inkjet or printing, applying the material to the surface to be formed, and then fixing the material by drying, baking, solidifying, etc., and then etching the material using photolithography or the like.

[0059] Examples of quantum dots include nano-sized particles such as Group 14 elements, Group 15 elements, Group 16 elements, compounds consisting of multiple Group 14 elements, compounds of elements belonging to Groups 4 to 14 and Group 16 elements, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, various semiconductor clusters, and metal halide perovskites.

[0060] Specifically, cadmium selenide (CdSe), cadmium sulfide (CdS), cadmium telluride (CdTe), zinc selenide (ZnSe), zinc oxide (ZnO), zinc sulfide (ZnS), zinc telluride (ZnTe), mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), indium arsenide (InAs), indium phosphide (InP), gallium arsenide (GaAs), gallium phosphide (GaP), indium nitride (InN), gallium nitride (GaN), indium antimonide (InSb), gallium antimonide (GaSb), phosphorus Aluminum selenide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), lead(II) selenide (PbSe), lead(II) telluride (PbTe), lead(II) sulfide (PbS), indium selenide (In2Se3), indium telluride (In2Te3), indium sulfide (In2S3), gallium selenide (Ga2Se3), arsenic(III) sulfide (As2S3), arsenic(III) selenide (As2Se3), arsenic(III) telluride (As2Te3), antimony(III) sulfide (Sb2S3), antimony(III) selenide (III ) (Sb2Se3), antimony(III) telluride (Sb2Te3), bismuth(III) sulfide (Bi2S3), bismuth(III) selenide (Bi2Se3), bismuth(III) telluride (Bi2Te3), silicon (Si), silicon carbide (SiC), germanium (Ge), tin (Sn), selenium (Se), tellurium (Te), boron (B), carbon (C), phosphorus (P), boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), aluminum nitride (AlN), aluminum sulfide (Al2S3), barium sulfide (BaS), barium selenide (BaSe), barium telluride (BaTe), calcium sulfide (CaS), calcium selenide (CaSe), calcium telluride (CaTe), beryllium sulfide (BeS), beryllium selenide (BeSe), beryllium telluride (BeTe), magnesium sulfide (MgS), magnesium selenide (MgSe), germanium sulfide (GeS), germanium selenide (GeSe), germanium telluride (GeTe), tin(IV) sulfide (SnS2), tin(II) sulfide (SnS), tin(II) selenide (SnSe), tin(II) telluride (SnTe),Lead(II) oxide (PbO), copper(I) fluoride (CuF), copper(I) chloride (CuCl), copper(I) bromide (CuBr), copper(I) iodide (CuI), copper(I) oxide (Cu2O), copper(I) selenide (Cu2Se), nickel(II) oxide (NiO), cobalt(II) oxide (CoO), cobalt(II) sulfide (CoS), iron(II) oxide (Fe3O4 ), iron(II) sulfide (FeS), manganese(II) oxide (MnO), molybdenum(IV) sulfide (MoS2), vanadium(II) oxide (VO), vanadium(IV) oxide (VO2), tungsten(IV) oxide (WO2), tantalum(V) oxide (Ta2O5), titanium oxide (TiO2, Ti2O5, Ti2O3, Ti5O9, etc.), zirconium oxide Examples of the quantum dots include, but are not limited to, ZnO (ZrO2), Si3N4, Ge3N4, Al2O3, Barium titanate (BaTiO3), a compound of selenium, zinc and cadmium (CdZnSe), a compound of indium, arsenic and phosphorus (InAsP), a compound of cadmium, selenium and sulfur (CdSeS), a compound of cadmium, selenium and tellurium (CdSeTe), a compound of indium, gallium and arsenic (InGaAs), a compound of indium, gallium and selenium (InGaSe), a compound of indium, selenium and sulfur (InSeS), a compound of copper, indium and sulfur (e.g. CuInS2) and combinations thereof. In addition, so-called alloy type quantum dots whose composition is expressed in any ratio may be used. For example, CdS, x Se (1-x) Alloy quantum dots represented by the formula (x is any number from 0 to 1) can change the emission wavelength by varying x, making them an effective means of obtaining blue light emission.

[0061] Quantum dot structures include core type, core-shell type, and core-multishell type, and any of these may be used, but by covering the core and forming a shell with another inorganic material with a wider band gap, the effects of defects and dangling bonds present on the nanocrystal surface can be reduced. This significantly improves the quantum efficiency of light emission, so it is preferable to use core-shell or core-multishell quantum dots. Examples of shell materials include zinc sulfide (ZnS) and zinc oxide (ZnO).

[0062] In addition, quantum dots have a high proportion of surface atoms, and therefore are highly reactive and prone to aggregation. For this reason, it is preferable that a protective agent is attached to the surface of the quantum dots or that a protective group is provided. By attaching the protective agent or providing the protective group, aggregation can be prevented and solubility in a solvent can be increased. It is also possible to reduce reactivity and improve electrical stability. Examples of protective agents (or protective groups) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; trialkyl phosphines such as tripropyl phosphine, tributyl phosphine, trihexyl phosphine, and trioctyl phosphine; polyoxyethylene alkyl phenyl ethers such as polyoxyethylene n-octyl phenyl ether and polyoxyethylene n-nonyl phenyl ether; tertiary amines such as tri(n-hexyl)amine, tri(n-octyl)amine, and tri(n-decyl)amine; and amines such as tripropyl phosphine oxide, tributyl phosphine oxide, trihexyl phosphine oxide, and tridecyl phosphine oxide. Examples of the organic phosphorus compounds include polyethylene glycol dilaurate, polyethylene glycol distearate, and other polyethylene glycol diesters; organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, and quinolines; aminoalkanes such as hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine; dialkyl sulfides such as dibutyl sulfide; dialkyl sulfoxides such as dimethyl sulfoxide and dibutyl sulfoxide; organic sulfur compounds such as sulfur-containing aromatic compounds such as thiophene; higher fatty acids such as palmitic acid, stearic acid, and oleic acid; alcohols; sorbitan fatty acid esters; fatty acid-modified polyesters; tertiary amine-modified polyurethanes; and polyethyleneimines.

[0063] When the substance contained in the color conversion layer 205 is QD, the QD has a continuous absorption spectrum from the vicinity of its own emission wavelength to the shorter wavelength side, with the absorption intensity increasing with the shorter the wavelength of light. Therefore, in the case of a display that requires emission of multiple colors, the luminescent center substance contained in the light-emitting device of each color pixel can be a common substance, and it is not necessary to fabricate separate light-emitting devices for each pixel color as shown in Figure 1(B), and the light-emitting device can be fabricated relatively inexpensively.

[0064] FIG. 1B shows an example of a pixel that emits three colors of light: blue, green, and red. 208B is a first pixel that emits blue light. The first pixel 208B has a first electrode 201B and a second electrode 203, one of which is an anode and the other is a cathode. Alternatively, one of which may be a reflective electrode and the other a semi-transmissive semi-reflective electrode. Similarly, a second pixel 208G that emits green light and a third pixel 208R that emits red light are shown, each having a first electrode 201G and a second electrode 203, and a first electrode 201R and a second electrode 203. FIG. 1B shows an example of a configuration in which the first electrodes 201B, 201G, and 201R are reflective electrodes and anodes, and the second electrode 203 is a semi-transmissive semi-reflective electrode. The first electrodes 201B to 201R are formed on an insulator 200. In order to prevent light from being mixed with adjacent pixels, a black matrix 206 is preferably provided between the pixels. The black matrix 206 may also serve as a bank when a color conversion layer is formed by an inkjet method or the like.

[0065] FIG. 1C shows pixels that emit four colors of light: blue, green, red, and white. 208W is a fourth pixel that emits white light. The fourth pixel 208W has a first electrode 201W and a second electrode 203, one of which is an anode and the other is a cathode. Either of these may be a reflective electrode and the other may be a semi-transmissive semi-reflective electrode. The first electrode 201W is formed on the insulator 200. In addition, it is preferable that a black matrix 206 is provided between the pixels to prevent light from being mixed with adjacent pixels. The black matrix 206 may also serve as a bank when forming a color conversion layer by an inkjet method or the like.

[0066] An EL layer 202 is sandwiched between the first electrodes 201B, 201G, 201R, 201W and the second electrode 203 in the first pixel 208B to the fourth pixel 208W. The EL layer 202 may be common to the first pixel 208B to the fourth pixel 208W or may be separate, but it is easier to manufacture and more cost-effective to have a common EL layer for multiple pixels. In addition, the EL layer 202 is usually composed of multiple layers with separate functions, but a part of the EL layer 202 may be shared by multiple pixels and a part may be independent for each pixel.

[0067] The first pixel 208B to the fourth pixel 208W have a first light-emitting device 207B, a second light-emitting device 207G, a third light-emitting device 207R, and a fourth light-emitting device 207W each composed of a first electrode, a second electrode, and an EL layer. Note that in Figs. 1B and 1C, the first pixel 208B to the fourth pixel 208W have a common EL layer 202.

[0068] The first light-emitting device 207B to the fourth light-emitting device 207W can be light-emitting devices having a microresonant structure by using one of the first electrode and the second electrode as a reflective electrode and the other as a semi-transmissive semi-reflective electrode. The wavelength at which light can be resonated is determined by the optical distance 209 between the surface of the reflective electrode and the surface of the semi-transmissive semi-reflective electrode. The optical distance 209 can be set to an integer multiple of λ / 2, where λ is the wavelength to be resonated, to amplify light of wavelength λ. The optical distance 209 can be adjusted by a hole injection layer of the EL layer, a hole transport layer, a transparent electrode layer formed on the reflective electrode as a part of the electrode, or the like. In the light-emitting devices of FIG. 1(B) and FIG. 1(C), the EL layer is common to the first light-emitting device 207B to the fourth light-emitting device 207W, and the luminescence center material is also the same, so that the optical distance 209 of the light-emitting device is common to the first pixel 208B to the fourth pixel 208W, and can be easily formed. When the EL layer 202 is separately formed for each pixel, the optical distance 209 may be formed in accordance with the light from the EL layer.

[0069] The protective layer 204 is provided on the second electrode 203. The protective layer 204 may be provided to protect the first light-emitting device 207B to the fourth light-emitting device 207W from substances or environments that may adversely affect the first light-emitting device 207B to the fourth light-emitting device 207W. The protective layer 204 may be made of an oxide, a nitride, a fluoride, a sulfide, a ternary compound, a metal, a polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium 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, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, or the like; a nitride containing titanium and aluminum; an oxide containing titanium and aluminum; an oxide containing aluminum and zinc; a sulfide containing manganese and zinc; a sulfide containing cerium and strontium; an oxide containing erbium and aluminum; an oxide containing yttrium and zirconium, or the like.

[0070] By bonding the color conversion layer and the light emitting device with a resin having an appropriate refractive index, more light emitted from the light emitting layer can reach the color conversion layer. As a result, the light emission of the color conversion layer is intensified, and a highly efficient light emitting device can be manufactured. The resin having the appropriate refractive index may also serve as the protective layer 204, or may be further provided between the protective layer 204 and the color conversion layer. The refractive index of the resin is preferably 1.4 to 2.0, and more preferably 1.7 to 1.9. The presence of a layer with a high refractive index between the transparent electrode and the color conversion layer reduces the light loss due to the thin film mode, and a more efficient light emitting device can be obtained.

[0071] In addition, since the first pixel 208B emits light not passing through a color conversion layer, it is preferable that the first pixel 208B is a pixel that emits blue light, which has the highest energy among the three primary colors of light. For the same reason, when the first light-emitting device 207B to the fourth light-emitting device 207W emit light of the same color, it is preferable that the light-emitting device emits blue light. In this case, it is advantageous in terms of cost that the luminescent center substances contained in these light-emitting devices are the same substance, but different luminescent center substances may be used.

[0072] In addition, in the case where a light-emitting device is not produced for each color of a pixel, the light emitted by the light-emitting center substance of the light-emitting device is preferably blue light (the peak wavelength of the emission spectrum is 440 nm to 520 nm, preferably about 420 nm to 480 nm). The peak wavelength of the emission spectrum of the light-emitting center substance is calculated from the PL spectrum in a solution state. Since the relative dielectric constant of the organic compound constituting the EL layer of the light-emitting device is about 3, in order to avoid discrepancy with the emission spectrum of the light-emitting device, the relative dielectric constant of the solvent for putting the light-emitting center substance into a solution state is preferably 1 to 10 at room temperature, more preferably 2 to 5. Specific examples of the solvent include hexane, benzene, toluene, diethyl ether, ethyl acetate, chloroform, chlorobenzene, and dichloromethane. In addition, a general-purpose solvent having a relative dielectric constant of 2 to 5 at room temperature, high solubility, is more preferable, and for example, toluene or chloroform is preferable.

[0073] The color conversion layer 205G contains a substance that absorbs the light from the second light emitting device 207G and emits light. The light emitted from the second light emitting device 207G enters the color conversion layer 205G, where it is converted into green light with a long wavelength (peak wavelength of the emission spectrum is 500 nm to 600 nm, preferably 500 nm to 560 nm) and emitted. 205R is also a color conversion layer, and the color conversion layer 205R contains a substance that absorbs the light from the third light emitting device 207R and emits light. The light emitted from the third light emitting device 207R enters the color conversion layer 205R, where it is converted into red light with a long wavelength (peak wavelength of the emission spectrum is 600 nm to 750 nm, preferably about 610 nm to 700 nm) and emitted. It is preferable that the color conversion layer 205G and the color conversion layer 205R contain a substance that performs color conversion, such as QD, at a concentration that sufficiently absorbs the light from the light emitting device and does not transmit the light from the light emitting device as much as possible.

[0074] 205W is also a color conversion layer, and contains a substance that absorbs light from the fourth light-emitting device 207W and emits light. The light emitted from the fourth light-emitting device 207W enters the color conversion layer 205W, where it is converted into yellow light with a long wavelength (peak wavelength of the emission spectrum is about 560 nm to 610 nm, preferably 580 nm to 595 nm) and emitted. The color conversion layer 205W contains at least one or more rare earth elements such as europium, cerium, and yttrium, and can efficiently convert blue light emission into yellow light emission. The color conversion layer 205W contains a substance that performs color conversion to an extent that it moderately transmits light from the light-emitting device, and the light converted by the color conversion layer 205W and the light from the light-emitting device that has transmitted through the color conversion layer 205W are mixed to produce white light emission.

[0075] Each of these pixels may further include a color filter.

[0076] In a light-emitting device having such a configuration, the amount of light that reaches the color conversion layer is the amount excluding optical loss due to absorption by the electrodes, optical loss due to the evanescent mode, and optical loss due to light confinement resulting from the refractive index difference between the joined resin and the light-emitting device. For this reason, it is necessary to reduce these losses.

[0077] 2A to 2C, the light-emitting device 207 has a structure as shown in Fig. 2. A light-emitting device used in a light-emitting device of one embodiment of the present invention will be described below.

[0078] The light-emitting device shown in FIG. 2(A) has a first electrode 101, a second electrode 102, and an EL layer 103. The EL layer includes at least a layer made of a material having a low refractive index, and the refractive index is the refractive index of blue light emitted by a luminescent center substance (the peak wavelength of the emission spectrum is from 440 nm to 520 nm, preferably from about 420 nm to 480 nm), for example, a layer made of a material having a refractive index of 1.75 or less for light with a wavelength of 467 nm.

[0079] The EL layer 103 has a light-emitting layer 113, and may have various functional layers in addition to the hole injection layer 111 and / or the hole transport layer 112, the electron transport layer 114 and / or the electron injection layer 115. The light-emitting layer 113 contains a light-emitting material, and the light-emitting device 207 obtains light emission from the light-emitting material. The light-emitting layer 113 may contain a host material or other materials. The layer made of a material having a refractive index of 1.75 or less for light of a wavelength of 467 nm may be any layer other than the light-emitting layer 113, but is preferably any one or more of the hole injection layer 111, the hole transport layer 112, and the electron transport layer 114. The presence of a layer with a small refractive index inside the EL layer suppresses evanescent mode and thin film mode in which light is lost as optical loss inside the device, and improves light extraction efficiency. Therefore, a light-emitting device with good external quantum efficiency can be obtained. It is preferable that the layer with a small refractive index is provided on the electrode side from which light is emitted rather than the light-emitting layer.

[0080] Next, an example of a detailed structure and material of the above-mentioned light-emitting device will be described. As described above, the light-emitting device according to one embodiment of the present invention has an EL layer 103 consisting of a plurality of layers between a pair of electrodes, the first electrode 101 and the second electrode 102, and any part of the EL layer 103 includes a layer having a refractive index of 1.75 or less, preferably 1.65 or less, for light with a wavelength of 467 nm, or a layer made of a material having a refractive index of 1.75 or less, preferably 1.65 or less, for light with a wavelength of 467 nm. Since a small refractive index reduces optical loss and improves the light extraction efficiency of the light-emitting device, the refractive index is preferably 1.74 or less, more preferably 1.73 or less, more preferably 1.72 or less, more preferably 1.71 or less, more preferably 1.70 or less, more preferably 1.69 or less, more preferably 1.68 or less, more preferably 1.67 or less, more preferably 1.66 or less, and more preferably 1.65 or less. Note that the refractive index is the ordinary refractive index, or the average refractive index of the ordinary refractive index and the extraordinary refractive index.

[0081] The first electrode 101 is preferably formed using a metal, alloy, conductive compound, or a mixture thereof having a large work function (specifically, 4.0 eV or more). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like. As an example of a manufacturing method, indium oxide-zinc oxide may be formed by a sputtering method using a target containing indium oxide and 1 to 20 wt % zinc oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) may also be formed by a sputtering method using a target containing indium oxide and 0.5 to 5 wt % tungsten oxide and 0.1 to 1 wt % zinc oxide. Other examples include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and nitrides of metal materials (e.g., titanium nitride). Graphene can also be used. By using a composite material described later for the layer in contact with the first electrode 101 in the EL layer 103, it becomes possible to select an electrode material regardless of the work function.

[0082] The EL layer 103 preferably has a laminated structure, but the laminated structure is not particularly limited, and various layer structures such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier block layer, an exciton block layer, and a charge generation layer can be applied as described above. In this embodiment, two types of structures will be described: a structure having an electron transport layer 114 and an electron injection layer 115 in addition to a hole injection layer 111, a hole transport layer 112, and a light-emitting layer 113 as shown in FIG. 2(A); and a structure having an electron transport layer 114, an electron injection layer 115, and a charge generation layer 116 in addition to a hole injection layer 111, a hole transport layer 112, and a light-emitting layer 113 as shown in FIG. 2(B). The materials constituting each layer are specifically described below.

[0083] The hole-injection layer 111 is a layer containing a substance having an acceptor property. As the substance having an acceptor property, either an organic compound or an inorganic compound can be used.

[0084] As the substance having acceptor properties, a compound having an electron-withdrawing group (a halogen group or a cyano group) can be used, and examples thereof include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferred. Radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) [3] are preferred because they have a very high electron-accepting property, and specific examples thereof include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds described above, inorganic compounds such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used as the acceptor material. In addition, the hole injection layer 111 can be formed by using phthalocyanine complex compounds such as phthalocyanine (abbreviation: HPc) and copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), or polymer compounds such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS).A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) when an electric field is applied.

[0085] A composite material in which the above-mentioned acceptor substance is contained in a material having a hole transport property can also be used as the hole injection layer 111. Note that by using a composite material in which the acceptor substance is contained in a material having a hole transport property, a material for forming an electrode can be selected regardless of the work function. That is, not only a material with a high work function but also a material with a low work function can be used as the first electrode 101.

[0086] As a material having a hole transport property used in the composite material, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as a material having a hole transport property used in the composite material, a 1×10 -6 cm 2 A material having a hole mobility of 100 / Vs or more is preferable. Specific examples of organic compounds that can be used as a material having a hole transport property in a composite material are listed below.

[0087] Examples of aromatic amine compounds that can be used in the composite material include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B). Specific examples of the carbazole derivative include 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCA3), Carbazolyl (abbreviation: PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-10-phenylanthracen-9-yl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. It may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA). Note that the organic compound of one embodiment of the present invention can also be used.

[0088] In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0089] The material having hole transport properties used in the composite material preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen atom of the amine via an arylene group. Note that it is preferable that the second organic compound is a substance having an N,N-bis(4-biphenyl)amino group, because a light-emitting device with a long life can be fabricated. Specific examples of the second organic compound include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan- 8-yl-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d] Furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: : BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4-(2;1'-binaphthyl-6-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4-(6;2'-binaphthyl-2-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4-(1;2'-binaphthyl-4-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNαNB), 4-(1;2'-binaphthyl-5-yl)-4 ',4''-Diphenyltriphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-(1-naphthyl)-4'-phenyltriphenylamine nylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyl Triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl) Triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP) ), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,Examples include 9'-spirobi-9H-fluorene-1-amine.

[0090] Note that the material having a hole-transporting property used in the composite material is more preferably a substance having a relatively deep HOMO level of −5.7 eV or more and −5.4 eV or less. When the material having a hole-transporting property used in the composite material has a relatively deep HOMO level, it becomes easy to inject holes into the hole-transporting layer 112, and it becomes easy to obtain a light-emitting device with a long lifetime.

[0091] The refractive index of the layer can be reduced by further mixing any one or more of an alkali metal fluoride, an alkaline earth metal fluoride, and an alkyl fluoride into the composite material (preferably with an atomic ratio of fluorine atoms in the layer of 20% or more). This also makes it possible to form a layer with a low refractive index inside the EL layer 103, and improve the external quantum efficiency of the light-emitting device. In the composite material mixed with the above fluoride, the spin density decreases as the amount of fluoride increases, so that the spin density of the composite material when measured by ESR is 1.0×10 18 spins / cm 3 In addition, when a fluoride is mixed into the hole injection layer, it is preferable to use an inorganic compound, particularly molybdenum oxide, as the acceptor material.

[0092] In addition, the refractive index of the hole injection layer 111 can also be reduced by using an organic compound with a small refractive index, such as 1,1-bis-(4-bis(4-methyl-phenyl)-amino-phenyl)-cyclohexane (abbreviation: TAPC), as a material having hole transport properties.

[0093] By forming the hole injection layer 111, the hole injection property is improved, and a light emitting device with a low driving voltage can be obtained. In addition, organic compounds having acceptor properties are easy to use because they can be easily evaporated and formed into a film.

[0094] The hole transport layer 112 is formed by including a material having a hole transport property. -6 cm 2 It is preferable that the hole mobility is 1 / Vs or more.

[0095] Examples of the material having the hole transport property include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), 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-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: B PAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: Aromatic amines such as 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), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF). Compounds with a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), and compounds with a carbazole skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Note that the substances exemplified as the materials having hole transport properties used for the composite material of the hole injection layer 111 can also be suitably used as the material for forming the hole transport layer 112.

[0096] The light-emitting layer 113 contains a light-emitting substance and a host material. The light-emitting layer 113 may contain other materials at the same time. The light-emitting layer 113 may also be a laminate of two layers having different compositions.

[0097] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting substances. Note that one embodiment of the present invention is more preferably applicable to the case where the light-emitting layer 113 is a layer exhibiting fluorescent light, in particular, a layer exhibiting blue fluorescent light.

[0098] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include the following: In addition, fluorescent substances other than these can also be used.

[0099] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 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]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 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: 2DPA BPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6 -methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine Amine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (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), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b ]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds such as pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred because they have high hole trapping properties and excellent luminous efficiency and reliability.

[0100] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, examples of materials that can be used include the following.

[0101] Organometallic iridium complexes with 4H-triazole skeletons such as 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-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), and tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]) are also available. Organometallic iridium complexes having a 1H-triazole skeleton, such as tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), fac-tris[(1-2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and 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) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’] Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are examples of such compounds that exhibit blue phosphorescence and have emission peaks at 440 nm to 520 nm.

[0102] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-( Organometallic iridium complexes having a pyrimidine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and organometallic iridium complexes having a pyrazine skeleton, such as tris(2-phenylpyridinato-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(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ In addition to organometallic iridium complexes having a pyridine skeleton such as iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]) can be mentioned. These are compounds that mainly exhibit green phosphorescence, and have an emission peak at 500 nm to 600 nm. In addition, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0103] In addition, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ In addition to organometallic iridium complexes with a pyridine skeleton such as iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]) are examples of such compounds that exhibit red phosphorescence and have an emission peak at 600 nm to 700 nm. Furthermore, an organometallic iridium complex having a pyrazine skeleton can emit red light with good chromaticity.

[0104] In addition to the phosphorescent compounds described above, known phosphorescent light-emitting substances may be selected and used.

[0105] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also included are metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), which are shown in the following structural formulas.

[0106] [ka]

[0107] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ) shown in the following structural formula, 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'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: P Heterocyclic compounds having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and the triazine skeleton are preferred because they are stable and reliable. In particular, the benzofuropyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuropyrazine skeleton, and the benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. In addition, among the skeletons having a π-electron rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are preferred because they are stable and reliable.In addition, the furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. In addition, the pyrrole skeleton is particularly preferably an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because the electron donating property of the π-electron-rich heteroaromatic ring and the electron accepting property of the π-electron-deficient heteroaromatic ring are both strong, and the energy difference between the S1 level and the T1 level is small, so that thermally activated delayed fluorescence can be efficiently obtained. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. In addition, an aromatic amine skeleton, a phenazine skeleton, or the like can be used as the π-electron-rich skeleton. In addition, examples of the π-electron-deficient skeleton that can be used include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring or a heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0108] [ka]

[0109] TADF materials are materials that have a small difference between the S1 and T1 levels and have the function of converting triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy by a small amount of thermal energy (reverse intersystem crossing), and singlet excitation states can be generated efficiently. In addition, triplet excitation energy can be converted into light emission.

[0110] In addition, exciplexes (also called exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 level and the T1 level and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0111] As an index of the T1 level, a phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) may be used. For a TADF material, when a tangent is drawn at the base of the short wavelength side of the fluorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the S1 level, and a tangent is drawn at the base of the short wavelength side of the phosphorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0112] In addition, when a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0113] As the host material of the light-emitting layer, various carrier transporting materials such as a material having an electron transporting property, a material having a hole transporting property, or the above-mentioned TADF material can be used.

[0114] As a material having hole transport properties, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton is preferable. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), 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-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP ... mBPAFLP, 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBBi1BP), 4-(1-naphthyl)-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'-bifluoren-2-amine (abbreviation: PCBASF) and other aromatic amine skeletons. Compounds with a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), compounds with a carbazole skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compound include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transport properties, and contribute to reducing the driving voltage. In addition, the organic compounds listed as examples of the first substance above can also be used.

[0115] Examples of materials having electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)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), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), as well as organic compounds having a π-electron-deficient heteroaromatic ring skeleton.Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), Heterocyclic compounds with polyazole skeletons such as 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: TPBI), and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) are also available. 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]dibenzo[f,h]quinoxaline Examples of the heterocyclic compounds include heterocyclic compounds having a diazine skeleton such as 4,6mPnP2Pm, 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and heterocyclic compounds having a pyridine skeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB). Among the above, heterocyclic compounds having a diazine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0116] As a TADF material that can be used as a host material, the same TADF materials listed above can be used. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy by reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby increasing the light-emitting efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0117] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0118] It is also preferable to use a TADF material that emits light at a wavelength that overlaps with the wavelength of the lowest energy absorption band of the fluorescent material, since this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission of light.

[0119] In addition, in order to efficiently generate singlet excitation energy from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. In addition, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. For this purpose, it is preferable that the fluorescent material has a protective group around the luminophore (skeleton causing light emission) of the fluorescent material. As the protective group, a substituent having no π bond is preferable, and a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms are mentioned, and it is more preferable that there are a plurality of protective groups. Since a substituent having no π bond has poor function of transporting carriers, the distance between the TADF material and the luminophore of the fluorescent material can be increased without affecting carrier transport or carrier recombination. Here, the luminophore refers to an atomic group (skeleton) causing light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, and a phenothiazine skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have a high fluorescence quantum yield.

[0120] When a fluorescent emitting material is used as the emitting material, a material having an anthracene skeleton is suitable as the host material. When a material having an anthracene skeleton is used as the host material of the fluorescent emitting material, it is possible to realize an emitting layer having both good luminous efficiency and durability. As a material having an anthracene skeleton to be used as the host material, a material having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, it is preferable because the injection and transport properties of holes are improved, but when the host material contains a benzocarbazole skeleton in which a benzene ring is further condensed to carbazole, the HOMO is shallower by about 0.1 eV than that of carbazole, making it easier for holes to enter, which is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferable because the HOMO is shallower by about 0.1 eV than that of carbazole, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a material having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such a material include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: CzPA), and 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: CzPA). Examples of such compounds include carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), and 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth).In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices since they exhibit very good properties.

[0121] The host material may be a mixture of a plurality of substances, and when a mixture of host materials is used, it is preferable to mix a material having an electron transporting property with a material having a hole transporting property. By mixing a material having an electron transporting property with a material having a hole transporting property, the transporting property of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the content of the material having a hole transporting property to the material having an electron transporting property may be from 1:19 to 19:1 (material having a hole transporting property:material having an electron transporting property).

[0122] A phosphorescent material can be used as a part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0123] In addition, these mixed materials may form an exciplex. It is preferable to select a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, because this makes energy transfer smooth and allows efficient light emission. In addition, the use of this structure is preferable because the driving voltage is reduced.

[0124] At least one of the materials forming the exciplex may be a phosphorescent material, which allows the triplet excitation energy to be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0125] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transport properties is equal to or higher than the HOMO level of the material having electron transport properties. It is also preferable that the LUMO level of the material having hole transport properties is equal to or higher than the LUMO level of the material having electron transport properties. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0126] The formation of an exciplex can be confirmed, for example, by comparing the emission spectrum of a material having hole transport properties, the emission spectrum of a material having electron transport properties, and the emission spectrum of a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectrum of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of an exciplex can be confirmed by comparing the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and the transient PL of a mixed film obtained by mixing these materials, and observing the difference in transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component than the transient PL lifetime of each material, or the proportion of delayed components becoming larger. The above-mentioned transient PL may also be read as transient electroluminescence (EL). That is, the formation of an exciplex can also be confirmed by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and the transient EL of a mixed film obtained by mixing these materials, and observing the difference in transient response.

[0127] In one embodiment of the present invention, the light emitted from the light-emitting device is color-converted by photoluminescence. When obtaining colors corresponding to the three primary colors of light without making separate light-emitting devices, the light emitted from the light-emitting device is preferably a light-emitting device that emits blue light having the highest energy among the three primary colors, or a light-emitting device that emits light in the purple to ultraviolet range when blue light is also converted.

[0128] The electron transport layer 114 is a layer containing a substance having an electron transport property. As the substance having an electron transport property, any of the substances exemplified above as the substance having an electron transport property that can be used as the host material can be used.

[0129] The electron transport layer preferably contains a material having an electron transport property and an element, compound, or complex of an alkali metal or an alkaline earth metal. The electron transport layer 114 has an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600. -7 cm 2 / Vs or more 5×10 -5 cm 2 / Vs or less. By lowering the electron transportability in the electron transport layer 114, the amount of electrons injected into the light-emitting layer can be controlled, and the light-emitting layer can be prevented from becoming in an electron excess state. This configuration is particularly preferable because the lifetime is improved when the hole injection layer is formed of a composite material and the HOMO level of the material having hole transportability in the composite material is a substance having a relatively deep HOMO level of -5.7 eV or more and -5.4 eV or less. In this case, the material having electron transportability preferably has a HOMO level of -6.0 eV or more. In addition, the material having electron transportability is preferably an organic compound having an anthracene skeleton, and more preferably an organic compound having both an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing 5-membered skeleton or a nitrogen-containing 6-membered skeleton, and particularly preferably has a nitrogen-containing 5-membered skeleton or a nitrogen-containing 6-membered skeleton containing two heteroatoms in the ring, such as a pyrazole ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring. In addition, the simple substance, compound, or complex of an alkali metal or an alkaline earth metal preferably contains an 8-hydroxyquinolinato structure. Specifically, for example, 8-hydroxyquinolinato-lithium (abbreviation: Liq) and 8-hydroxyquinolinato-sodium (abbreviation: Naq) can be mentioned. In particular, a complex of a monovalent metal ion, particularly a lithium complex, is preferable, and Liq is more preferable. In addition, when the 8-hydroxyquinolinato structure is contained, a methyl-substituted product (for example, a 2-methyl-substituted product or a 5-methyl-substituted product) can also be used. In the electron transport layer, it is preferable that the alkali metal or alkaline earth metal simple substance, compound, or complex has a concentration difference (including the case where the concentration difference is 0) in the thickness direction.

[0130] Between the electron transport layer 114 and the second electrode 102, a layer containing an alkali metal or an alkaline earth metal, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), or 8-hydroxyquinolinato-lithium (abbreviation: Liq), or a compound thereof may be provided as the electron injection layer 115. The electron injection layer 115 may be a layer made of a substance having an electron transport property containing an alkali metal or an alkaline earth metal or a compound thereof, or an electride. Examples of the electride include a substance in which electrons are added at a high concentration to a mixed oxide of calcium and aluminum.

[0131] Note that a layer containing a fluoride of the alkali metal or alkaline earth metal in a substance having an electron transporting property (preferably an organic compound having a bipyridine skeleton) at a concentration at which the fluoride is in a microcrystalline state or higher (50 wt % or higher) can be used as the electron injection layer 115. Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0132] The effect of introducing a low refractive index layer is greater in the layer between the light emitting layer and the cathode than in the layer between the anode and the light emitting layer, and is greater in the electron transport layer than in the hole injection layer or hole transport layer, but it is more effective and preferable to provide a low refractive index layer on both of them. This effect improves the device characteristics when color conversion is performed, and a highly efficient color conversion light emitting device can be obtained.

[0133] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 (FIG. 2(B)). The charge generation layer is a layer capable of injecting holes into a layer in contact with the cathode side of the layer and electrons into a layer in contact with the anode side of the layer by applying a potential. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material listed above as a material capable of forming the hole injection layer 111. The P-type layer 117 may be formed by laminating a film containing an acceptor material and a film containing a hole transport material, both of which are materials that form the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the second electrode 102, which is the cathode, and the light-emitting device operates. In addition, since the organic compound according to one embodiment of the present invention is an organic compound having a low refractive index, a light-emitting device having good external quantum efficiency can be obtained by using the organic compound for the P-type layer 117.

[0134] It is preferable that the charge generating layer 116 is provided with either or both of an electron relay layer 118 and an electron injection buffer layer 119 in addition to the P-type layer 117 .

[0135] The electron relay layer 118 contains at least a substance having an electron transporting property, and has a function of preventing an interaction between the electron injection buffer layer 119 and the P-type layer 117 and smoothly transferring electrons. The LUMO level of the substance having an electron transporting property contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer in contact with the charge generating layer 116 in the electron transport layer 114. The specific energy level of the LUMO level of the substance having an electron transporting property used in the electron relay layer 118 is -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. Note that, as the substance having an electron transporting property used in the electron relay layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0136] The electron injection buffer layer 119 can be made of a material with high electron injection properties, such as an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide, or a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, or a carbonate), or a rare earth metal compound (including an oxide, a halide, or a carbonate)).

[0137] In addition, when the electron-injection buffer layer 119 is formed containing a substance having an electron-transporting property and a donor substance, as the donor substance, an alkali metal, an alkaline earth metal, a rare earth metal, and a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide, or a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, or a carbonate), or a rare earth metal compound (including an oxide, a halide, or a carbonate)), or an organic compound such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene can be used. Note that as the substance having an electron-transporting property, a material similar to the material constituting the electron-transporting layer 114 described above can be used.

[0138] The second electrode 102 may be made of a metal, alloy, electrically conductive compound, or mixture thereof having a small work function (specifically, 3.8 eV or less). Specific examples of such a cathode material include alkali metals such as lithium (Li) and cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these elements (MgAg, AlLi), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these elements. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide can be used as the second electrode 102 regardless of the magnitude of the work function. These conductive materials can be formed into a film by a dry method such as a vacuum deposition method or a sputtering method, an inkjet method, a spin coating method, etc. Also, they may be formed by a wet method using a sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0139] In addition, various methods, whether dry or wet, can be used to form the EL layer 103. For example, a vacuum deposition method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, or a spin coating method may be used.

[0140] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0141] The configuration of the layers provided between the first electrode 101 and the second electrode 102 is not limited to the above. However, a configuration in which a light-emitting region where holes and electrons recombine is provided at a position away from the first electrode 101 and the second electrode 102 is preferable so as to suppress quenching caused by the proximity of the light-emitting region to the metals used in the electrodes and the carrier injection layer.

[0142] In addition, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, particularly the carrier transport layer close to the recombination region in the light-emitting layer 113, are preferably composed of a substance having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0143] Next, an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also called a stacked element or a tandem element) will be described with reference to FIG. 2(C). This light-emitting device has a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has a structure almost similar to that of the EL layer 103 shown in FIG. 2(A). In other words, the light-emitting device shown in FIG. 2(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 2(A) or FIG. 2(B) can be said to be a light-emitting device having one light-emitting unit.

[0144] In Fig. 2(C), a first light-emitting unit 511 and a second light-emitting unit 512 are laminated between an anode 501 and a cathode 502, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 correspond to the first electrode 101 and the second electrode 102 in Fig. 2(A), respectively, and the same electrodes as those described in the description of Fig. 2(A) can be applied. In addition, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0145] The charge generation layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied between the anode 501 and the cathode 502. That is, in the case of FIG. 2(C), when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, the charge generation layer 513 only needs to inject electrons into the first light-emitting unit 511 and inject holes into the second light-emitting unit 512.

[0146] The charge generation layer 513 is preferably formed to have the same structure as the charge generation layer 116 described in FIG. 2B. A composite material of an organic compound and a metal oxide has excellent carrier injection and carrier transport properties, and therefore can realize low-voltage driving and low-current driving. When the anode side surface of the light-emitting unit is in contact with the charge generation layer 513, the charge generation layer 513 can also function as a hole injection layer of the light-emitting unit, and therefore the light-emitting unit does not need to be provided with a hole injection layer.

[0147] Furthermore, when an electron injection buffer layer 119 is provided in the charge generation layer 513, the electron injection buffer layer 119 plays the role of an electron injection layer in the light-emitting unit on the anode side, so that it is not necessarily necessary to form an electron injection layer in the light-emitting unit on the anode side.

[0148] 2C, a light-emitting device having two light-emitting units has been described, but the present invention can be applied to a light-emitting device having three or more light-emitting units stacked in the same manner. By disposing a plurality of light-emitting units between a pair of electrodes and separating them with a charge generation layer 513 as in the light-emitting device according to this embodiment, a light-emitting device that can emit light with high luminance while keeping the current density low and has a long life can be realized. In addition, a light-emitting device that can be driven at a low voltage and consumes low power can be realized.

[0149] FIG. 3 is a schematic diagram of a light-emitting device in which a light-emitting device having a plurality of light-emitting units is applied to one embodiment of the present invention, similarly to FIG. 2(C). An anode 501 is formed on a substrate 100, and a first light-emitting unit 511 having a first light-emitting layer 113-1 and a second light-emitting unit 512 having a second light-emitting layer 113-2 are stacked with a charge generation layer 513 interposed therebetween. Light emitted from the light-emitting device is emitted directly or via a color conversion layer 205. Note that color purity may be improved by further passing through color filters 225R, 225G, and 225B. Note that FIG. 3 illustrates a structure in which a color filter 225B is provided, but is not limited thereto. For example, in FIG. 3, an overcoat layer may be provided instead of the color filter 225B. As the overcoat layer, an organic resin material, typically an acrylic resin or a polyimide resin, may be used. Note that in this specification and the like, the color filter layer may be referred to as a colored layer, and the overcoat layer may be referred to as a resin layer, respectively. Therefore, the color filter 225R may be called a first colored layer, and the color filter 225G may be called a second colored layer.

[0150] In addition, each layer and electrode such as the above-mentioned EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer can be formed by using, for example, a deposition method (including a vacuum deposition method), a droplet discharge method (also called an ink-jet method), a coating method, a gravure printing method, etc. In addition, they may contain a low molecular weight material, a medium molecular weight material (including an oligomer and a dendrimer), or a polymer material.

[0151] Here, when focusing on the color reproducibility of a full-color display, it is essential to obtain light with good color purity in order to express a richer color gamut. Light emitted from organic compounds often has a broader spectrum than light emitted from inorganic compounds, so it is preferable to narrow the spectrum by using a microresonator structure (microcavity structure) in order to obtain light emitted with sufficient color purity.

[0152] In fact, a light-emitting device using an appropriate dopant and appropriately applying a microresonant structure can emit blue light corresponding to the Rec.2020 color gamut defined in the BT.2020 and BT.2100 standards. In this case, the microresonant structure of the light-emitting device has a configuration that intensifies blue light, thereby making it possible to obtain a light-emitting device with good color purity and high efficiency.

[0153] A light-emitting device having a microresonant structure can be obtained by configuring a pair of electrodes of the light-emitting device with a reflective electrode and a semi-transparent / semi-reflective electrode. The reflective electrode and the semi-transparent / semi-reflective electrode correspond to the above-mentioned first electrode 101 and second electrode 102, and one of them can be the reflective electrode and the other the semi-transparent / semi-reflective electrode.

[0154] In a light-emitting device with a microresonant structure, light emitted in all directions from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transparent and semi-reflective electrode, and resonates, amplifying light of a certain wavelength and making the light directional.

[0155] The reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%, and a resistivity of 1×10 -2 The resistivity is set to Ωcm or less. Examples of materials for forming the reflective electrode include aluminum (Al) and alloys containing Al. Examples of alloys containing Al include alloys containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as alloys containing Al and Ti, or Al, Ni, and La. Aluminum has a low resistance value and a high light reflectance. In addition, aluminum is abundant in the earth's crust and is inexpensive, so the cost of manufacturing a light-emitting device can be reduced by using aluminum. In addition, an alloy containing silver (Ag) or Ag and N (N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au)) may be used. Examples of the alloy containing silver include an alloy containing silver, palladium, and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, an alloy containing silver and gold, and an alloy containing silver and ytterbium. In addition, transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can be used.

[0156] A transparent electrode layer may be formed between the reflective electrode and the EL layer 103 as an optical path length adjustment layer using a light-transmitting conductive material, and the two layers of the reflective electrode and the transparent electrode may form the first electrode 101. By using a transparent electrode layer, the optical path length (cavity length) of the microresonant structure may be adjusted. Examples of light-transmitting conductive materials include metal oxides such as indium tin oxide (hereinafter, ITO), indium tin oxide containing silicon or silicon oxide (abbreviated as ITSO), indium oxide-zinc oxide (indium zinc oxide), indium oxide-tin oxide containing titanium, indium titanium oxide, and indium oxide containing tungsten oxide and zinc oxide.

[0157] The semi-transmissive and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1×10 -2 The resistivity is set to Ωcm or less. The semi-transmitting / semi-reflective electrode can be formed by using one or more conductive metals, alloys, conductive compounds, etc. Specifically, for example, metal oxides such as indium tin oxide (hereinafter, ITO), indium tin oxide containing silicon or silicon oxide (abbreviated as ITSO), indium oxide-zinc oxide, indium oxide-tin oxide containing titanium, indium-titanium oxide, indium oxide containing tungsten oxide and zinc oxide, etc. can be used. In addition, a metal thin film that transmits light (preferably, a thickness of 1 nm or more and 30 nm or less) can be used. As the metal, for example, Ag, or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, etc. can be used.

[0158] The reflective electrode and the semi-transmissive and semi-reflective electrode may be either the first electrode 101 or the second electrode 102. In addition, they may be either an anode or a cathode.

[0159] In the case of a light-emitting device having a top emission structure, the light extraction efficiency can be improved by providing an organic cap layer on the surface of the second electrode 102 opposite to the surface in contact with the EL layer 103. By providing the organic cap layer, the refractive index difference at the electrode-air interface can be reduced, and the light extraction efficiency can be improved. The film thickness is preferably 5 nm to 120 nm. More preferably, it is 30 nm to 90 nm. In addition, the organic cap layer may be an organic compound layer having a molecular weight of 300 to 1200. In addition, it is preferable that the organic material is conductive. The semi-transmitting / semi-reflective electrode needs to be thin in order to maintain a certain degree of light transparency, and the conductivity may deteriorate. Here, by using a material having conductivity for the organic cap layer, the light extraction efficiency can be improved while ensuring conductivity, and the yield of the light-emitting device production can be improved. In addition, an organic compound that absorbs little light in the visible light region can be suitably used. The organic compound used for the EL layer 103 can also be used for the organic cap layer. In this case, since the organic capping layer can be formed in the same deposition apparatus or deposition chamber in which the EL layer 103 is formed, the organic capping layer can be formed easily.

[0160] In this light-emitting device, the optical distance (cavity length) between the reflective electrode and the semi-transmitting / semi-reflective electrode can be changed by changing the thickness of the transparent electrode provided in contact with the reflective electrode, the hole injection layer, the hole transport layer, and other carrier transport layers. This makes it possible to intensify light with resonating wavelengths and attenuate light with non-resonating wavelengths between the reflective electrode and the semi-transmitting / semi-reflective electrode.

[0161] In addition, in the microresonant structure (microcavity structure), it is preferable that the optical distance (optical path length) between the interface of the reflective electrode on the EL layer side and the interface of the semi-transparent semi-reflective electrode on the EL layer side is an integer multiple of λ / 2, where λnm is the wavelength to be amplified.

[0162] In addition, since the light reflected back by the reflective electrode (first reflected light) from the emitted light causes significant interference with the light (first incident light) that is directly incident on the semi-transmissive and semi-reflective electrode from the light-emitting layer, it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number equal to or greater than 1, and λ is the wavelength of the emitted light to be amplified). By adjusting the optical distance, the phase of the first reflected light and the first incident light can be aligned, thereby further amplifying the light emitted from the light-emitting layer.

[0163] The microcavity structure makes it possible to increase the intensity of light emitted from a specific wavelength in the front direction, thereby reducing power consumption and increasing the probability of light entering the color conversion layer.

[0164] It is known that the light narrowed through the microcavity structure has strong directivity perpendicular to the screen. On the other hand, the light passing through the color conversion layer using the above-mentioned QDs has almost no directivity because the light emitted from the QDs and the light-emitting organic compounds is emitted in all directions. Since some light emission from the light-emitting device is lost through the color conversion layer, in a display using a color conversion layer, the blue light, which is the shortest wavelength light, is obtained directly from the light-emitting device, and the green and red lights are light passing through the color conversion layer. Therefore, there is a difference in the light distribution characteristics between the green and red pixels and the blue pixels. Such a large difference in the light distribution characteristics creates viewing angle dependency and directly leads to a deterioration in display quality. The impact is particularly large when a large number of people are watching on a large screen such as a television.

[0165] Therefore, a light-emitting device of one embodiment of the present invention may have a structure that has a function of diffusing light to pixels that do not pass through a color conversion layer, or a structure that imparts directionality to pixels that pass through a color conversion layer.

[0166] The structure having the function of diffusing light may be provided on the optical path along which the light emitted from the light emitting device exits the light emitting device. The light emitted from the light emitting device having the microresonator structure has a strong directivity, but the light can be weakened by being diffused by the structure having the function of diffusing the light, or the diffused light can be made to have a directivity, and the light that passes through the color conversion layer and the light that does not pass through the color conversion layer can be made to have the same orientation characteristics. This can reduce the viewing angle dependency.

[0167] 4(A) to 4(C) show a configuration in which a structure 205B having a function of scattering light emitted from a first light-emitting device 207B is provided in a first pixel 208B. The structure 205B having a function of scattering light emitted from the first light-emitting device 207B may be a layer containing a first substance that scatters light emitted from the first light-emitting device as in Fig. 4(A) and Fig. 4(B), or may be a structure having a structure that scatters light emitted from the first light-emitting device as in Fig. 4(C).

[0168] 5(A) to (C) show modified examples. FIG. 5(A) has a layer (color filter 215B) that also functions as a blue color filter, instead of the structure 205B having the light scattering function in FIG. 4(A). Also, FIG. 5(B) and (C) show an embodiment having both the structure 205B having the light scattering function and the blue color filter 215B. Note that the blue color filter 215B may be formed in contact with the structure 205B having the light scattering function as in FIG. 5(B) and (C), but may be formed on another structure such as a sealing substrate. This allows the light emitting device to further improve color purity while scattering light with directionality. In addition, reflection of external light can be suppressed, so that a better display can be obtained.

[0169] The light from the first pixel 208B can be made to have low directivity by emitting the light from the first light-emitting device 207B via the structure 205B. This reduces the difference in light distribution characteristics due to color, making it possible to provide a light-emitting device with high display quality.

[0170] In addition, in the light-emitting device according to one embodiment of the present invention shown in Figures 6(A) and (B), means 210G and 210R for imparting directivity to the light emitted from the first color conversion layer are provided. Any means may be used for imparting directivity to the light emitted from the first color conversion layer, but for example, semi-transmissive semi-reflective layers may be formed to sandwich the color conversion layer, forming a microresonator structure. Note that Figure 6(A) shows an embodiment in which semi-transmissive semi-reflective layers are formed above and below the color conversion layer, and Figure 6(B) shows an embodiment in which the semi-transmissive semi-reflective layer on the light-emitting device side of the color conversion layer is also used as the second electrode (semi-transmissive semi-reflective electrode) of the light-emitting device.

[0171] The light from the second pixel 208G and the third pixel 208R can be made highly directional by providing means 210G and 210R for imparting directivity to the light emitted from the color conversion layer, respectively. This reduces the difference in light distribution characteristics due to color, resulting in a light emitting device with high display quality.

[0172] (Embodiment 2) In this embodiment, an organic compound having a hole transporting property that can be used for the hole injection layer 111 and the hole transport layer 112 of the light-emitting device 207 in the first embodiment will be described.

[0173] Among organic compounds with carrier transport properties that can be used in organic EL devices, 1,1-bis-(4-bis(4-methyl-phenyl)-amino-phenyl)-cyclohexane (abbreviation: TAPC) is known as one of the materials with a low refractive index. By using a material with a low refractive index in the EL layer, it is possible to obtain a light-emitting device that shows high external quantum efficiency, so it is expected that the use of TAPC will result in a light-emitting device with good external quantum efficiency.

[0174] Usually, there is a trade-off between high carrier transport and low refractive index. This is because the carrier transport in organic compounds is largely due to the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have a high refractive index. TAPC is a material that achieves an excellent balance between carrier transport and low refractive index. However, compounds with a 1,1-disubstituted cyclohexane structure such as TAPC have two bulky substituents inserted on one carbon of cyclohexane, which increases steric repulsion and induces instability of the molecule itself, making them unreliable. In addition, TAPC has a low glass transition point (Tg) and poor heat resistance due to its skeleton structure consisting of cyclohexane and a simple benzene ring.

[0175] One method for obtaining a hole transport material with high heat resistance and good reliability is to introduce an unsaturated hydrocarbon group, particularly a cyclic unsaturated hydrocarbon group, into the molecule. On the other hand, in order to obtain a material with a low refractive index, it is preferable to introduce a substituent with a low molecular refraction into the molecule. Examples of such a substituent include a saturated hydrocarbon group and a cyclic saturated hydrocarbon group.

[0176] In addition, materials used as carrier transport materials for organic EL devices preferably have a skeleton with high carrier transportability, and among them, aromatic amine skeletons are preferred because of their high hole transportability. In order to further improve carrier transportability, it is also possible to introduce two amine skeletons. However, as in the case of TAPC mentioned above, depending on the environment of the substituents arranged around it, the diamine structure may be detrimental to reliability.

[0177] As a compound that overcomes the trade-off and has carrier transportability, a low refractive index, and high reliability, the present inventors have found a monoamine compound in which the ratio of carbon atoms that form bonds with sp3 hybrid orbitals constituting a saturated hydrocarbon group is within a certain range. In particular, the monoamine compound is a material that has good reliability equivalent to that of conventional hole injection layer materials that have a normal refractive index. In addition, by devising the number of substituents and the substitution position of the substituents that have carbon atoms that form bonds with sp3 hybrid orbitals of the monoamine compound, a material with better properties can be obtained.

[0178] That is, the organic compound according to one embodiment of the present invention is a monoamine compound in which a first aromatic ring, a second aromatic ring, and a third aromatic ring are directly bonded to a nitrogen atom of an amine, and is a material for a hole transport layer or a hole injection layer of an organic EL device in which the refractive index of a layer made of the monoamine compound is 1.5 to 1.75. It is preferable that the ratio of carbons forming bonds via sp3 hybrid orbitals to the total number of carbons in the molecule of the monoamine compound is 23% to 55%.

[0179] Substituents composed of carbons that form bonds with sp3 hybrid orbitals are so-called saturated hydrocarbon groups or cyclic saturated hydrocarbon groups, and therefore have low molecular refraction. Therefore, the monoamine compound in which the carbons that form bonds with sp3 hybrid orbitals account for 23% to 55% of the total number of carbons in the molecule can be used as a material for hole transport layers and hole injection layers with low refractive index.

[0180] The monoamine compound is 1In the results of H-NMR measurements, it is preferable that the integral value of the signal below 4 ppm exceeds the integral value of the signal above 4 ppm. The signal below 4 ppm represents a chain or cyclic saturated hydrocarbon group, and the fact that the integral value exceeds the integral value of the signal above 4 ppm means that the number of hydrogen atoms constituting the saturated hydrocarbon group is greater than the number of hydrogen atoms constituting the unsaturated hydrocarbon. From this, the proportion of carbon in the molecule that forms bonds only with sp3 hybrid orbitals can be estimated. Here, the carbon of the unsaturated hydrocarbon group has fewer bonds that can bond with hydrogen. For example, when comparing benzene and cyclohexane, C6H6 and C6H 12 Taking this difference into account, 1 In the results of H-NMR measurement, the integral value of the signal below 4 ppm exceeds the integral value of the signal above 4 ppm, which means that about one-third of the carbon atoms in the molecule belong to saturated hydrocarbon groups. As a result, the monoamine compound is an organic compound with a small refractive index and can be suitably used as a material for hole transport layers and hole injection layers.

[0181] In addition, the monoamine compound preferably has at least one fluorene skeleton. The hole transport property of the monoamine compound having the fluorene skeleton is improved, and a light-emitting device using the monoamine compound as either or both of a hole transport layer material and a hole injection layer material can be a light-emitting device with good driving voltage. In addition, the fluorene skeleton is any one of the first aromatic ring, the second aromatic ring, and the third aromatic ring, and is directly bonded to the nitrogen atom of the amine, which contributes to making the HOMO level of the molecule shallow, and thus makes it easy to transfer holes, which is preferable.

[0182] When the monoamine compound is formed into a film by vapor deposition, the molecular weight thereof is preferably 400 or more and 1,000 or less.

[0183] The above monoamine compounds will now be described in more detail.

[0184] The monoamine compound is a triarylamine derivative in which a first aromatic ring, a second aromatic ring, and a third aromatic ring are bonded to a nitrogen atom of an amine. The first aromatic ring, the second aromatic ring, and the third aromatic ring are bonded to the nitrogen atom of the amine.

[0185] The first aromatic ring and the second aromatic ring each independently have 1 to 3 benzene rings. In addition, it is preferable that both the first aromatic ring and the second aromatic ring are hydrocarbon rings.

[0186] When the first aromatic ring and the second aromatic ring each have two or three benzene rings, the two or three benzene rings are preferably bonded to each other as a substituent, i.e., the first aromatic ring and the second aromatic ring are preferably a phenyl group, a biphenyl group, a terphenyl group, or a naphthylphenyl group.

[0187] Either or both of the first aromatic ring and the second aromatic ring have one to 12 carbon atoms and have one or more hydrocarbon groups in which carbons form bonds only through sp3 hybrid orbitals.

[0188] In the monoamine compound, the hydrocarbon group having 1 to 12 carbon atoms and bonded only to sp3 hybrid orbitals is bonded to either or both of the first aromatic ring or the second aromatic ring, the total number of carbon atoms contained in the hydrocarbon group bonded to one aromatic ring is 6 or more, and the total number of carbon atoms contained in the hydrocarbon group bonded to the first aromatic ring and the second aromatic ring is 8 or more, preferably 12 or more. By bonding the hydrocarbon group having a small molecular refraction in this way, the monoamine compound can be made into an organic compound having a small refractive index.

[0189] In order to maintain good carrier transportability, the total number of carbon atoms contained in the hydrocarbon group bonded to the first aromatic ring and the second aromatic ring is preferably 36 or less, and more preferably 30 or less. As described above, a larger number of π electrons derived from unsaturated bonds of carbon atoms is advantageous for carrier transport.

[0190] The hydrocarbon group having 1 to 12 carbon atoms and forming bonds only through sp3 hybrid orbitals is preferably an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms. Specifically, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a heptyl group, an octyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a decahydronaphthyl group, a cycloundecyl group, and a cyclododecyl group can be used, and a t-butyl group, a cyclohexyl group, and a cyclododecyl group are particularly preferred.

[0191] The third aromatic ring is a substituted or unsubstituted single ring or a substituted or unsubstituted fused ring having 3 or less rings. When the number of fused rings increases, the refractive index tends to increase, so that the refractive index can be maintained low. Similarly, when the number of fused rings increases, the absorption and emission of light in the visible region are observed, so that the material can be made less affected by absorption and emission. In addition, the third aromatic ring preferably has 6 to 13 carbon atoms in order to maintain a low refractive index. Specific examples of aromatic rings that can be used as the third aromatic ring include a benzene ring, a naphthalene ring, a fluorene ring, and an acenaphthylene ring. In particular, the third aromatic ring preferably includes a fluorene ring, and more preferably is a fluorene ring, because the hole transport property is good.

[0192] The monoamine compound having the above-mentioned structure is an organic compound having hole transport properties and a small refractive index, and therefore can be suitably used as a material for a hole transport layer or a material for a hole injection layer of an organic EL device. In addition, an organic EL device using the material for a hole transport layer or a material for a hole injection layer has a hole transport layer or a hole injection layer with a small refractive index, and therefore can be a light-emitting device with high luminous efficiency, i.e., high external quantum efficiency, current efficiency, and blue index. In addition, an organic EL device using the material for a hole transport layer or a material for a hole injection layer can be a light-emitting device with a good lifespan, since the material for a hole transport layer or a material for a hole injection layer is a monoamine compound, and the number of aromatic rings bonded to a saturated hydrocarbon group is limited, thereby reducing steric repulsion, thereby improving the stability of the molecule.

[0193] Among the above monoamine compounds, the organic compounds represented by the following general formula (G1) are particularly preferred.

[0194] [ka]

[0195] In the above general formula (G1), Ar 1 , Ar 2 each independently represents a benzene ring or a substituent in which two or three benzene rings are bonded to each other. 1 , Ar 2 Specific examples of the group include a phenyl group, a biphenyl group, a terphenyl group, and a naphthylphenyl group, and the phenyl group is particularly preferred in order to lower the refractive index and maintain the carrier transportability of the nitrogen atom.

[0196] In addition, Ar 1 , Ar 2 One or both of Ar have one or more hydrocarbon groups having 1 to 12 carbon atoms, in which carbons form bonds only through sp3 hybrid orbitals. The total number of carbons contained in the hydrocarbon group is 8 or more, and Ar 1 and Ar 2The total number of carbon atoms contained in the hydrocarbon group bonded to at least one of the above is 6 or more. As the hydrocarbon group having 1 to 12 carbon atoms in which carbons form bonds only through sp3 hybrid orbitals, an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms are preferred. Specifically, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a heptyl group, an octyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a decahydronaphthyl group, a cycloundecyl group, and a cyclododecyl group can be used, and a t-butyl group, a cyclohexyl group, and a cyclododecyl group are particularly preferred.

[0197] In addition, Ar 1 or Ar 2 When a plurality of linear alkyl groups having 1 or 2 carbon atoms are bonded to the hydrocarbon group, the linear alkyl groups may be bonded to each other to form a ring.

[0198] In addition, in the above general formula (G1), R 1 and R 2 Each independently represents an alkyl group having 1 to 4 carbon atoms. 1 and R 2 may be bonded to each other to form a ring. 3 represents an alkyl group having 1 to 4 carbon atoms; and u is an integer of 0 to 4.

[0199] Further, the organic compound of one embodiment of the present invention can be represented by the following general formulas (G2) to (G4).

[0200] [ka]

[0201] In the above general formula (G2), n, m, p, and r each independently represent 1 or 2, and s, t, and u each independently represent an integer from 0 to 4. Furthermore, n+p and m+r each independently represent 2 or 3. It is preferable that s, t, and u each independently represent 0.

[0202] In the above general formula (G2), R 1 , R 2 and R 3 each independently represents an alkyl group having 1 to 4 carbon atoms; R 4 and R 5 each independently represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. Examples of the hydrocarbon group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, etc. Examples of the hydrocarbon group having 1 to 4 carbon atoms include, in addition to the above, a butyl group.

[0203] Also, R 10 ~R 14 and R 20 ~R 24 each independently represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms and in which the carbons form bonds only through sp3 hybrid orbitals. As the hydrocarbon group having 1 to 12 carbon atoms and in which the carbons form bonds only through sp3 hybrid orbitals, an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms are preferred. Specifically, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a isobutyl group, a tert-butyl group, a pentyl group, a isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, a isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a heptyl group, an octyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a decahydronaphthyl group, a cycloundecyl group, a cyclododecyl group, and the like can be used, with a t-butyl group, a cyclohexyl group, and a cyclododecyl group being particularly preferred.

[0204] In addition, R 10 ~R 14 and R20 ~R 24 The total number of carbon atoms contained in R is 8 or more, and 10 ~R 14 or R 20 ~R 24 The total number of carbon atoms contained in at least one of the above is 6 or more.

[0205] In the above general formula (G2), when n is 2, the types of substituents, the number of substituents and the positions of bonds of the two phenylene groups may be the same or different; when m is 2, the types of substituents, the number of substituents and the positions of bonds of the two phenylene groups may be the same or different; when p is 2, the types of substituents, the number of substituents and the positions of bonds of the two phenyl groups may be the same or different; and when r is 2, the types of substituents, the number of substituents and the positions of bonds of the two phenyl groups may be the same or different.

[0206] When s is an integer from 2 to 4, a plurality of R 4 may be the same or different, and when t is an integer of 2 to 4, a plurality of R 5 may be the same or different, and when u is an integer of 2 to 4, a plurality of R 3 may be the same or different. 1 and R 2 may be bonded to each other to form a ring, R 4 , R 5 , R 10 ~R 14 and R 20 ~R 24 Adjacent groups may be bonded to each other to form a ring.

[0207] [ka]

[0208] In the above general formula (G3), R 1 , R 2 and R 3each independently represents an alkyl group having 1 to 4 carbon atoms; R 4 represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. Examples of the hydrocarbon group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, etc. Examples of the hydrocarbon group having 1 to 4 carbon atoms include, in addition to the above, a butyl group.

[0209] Each of n and p independently represents 1 or 2, and each of s and u independently represents an integer from 0 to 4, provided that n+p is 2 or 3. It is preferable that each of s and u independently represents 0.

[0210] Also, R 10 ~R 14 and R 20 ~R 24 each independently represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms and in which the carbon forms bonds only through sp3 hybrid orbitals. As the hydrocarbon group having 1 to 12 carbon atoms and in which the carbon forms bonds only through sp3 hybrid orbitals, an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms are preferred. Specifically, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, and a cyclododecyl group can be used, and a t-butyl group, a cyclohexyl group, and a cyclododecyl group are particularly preferred.

[0211] However, R 10 ~R 14 and R 20 ~R 24 The total number of carbon atoms contained in R is 8 or more, and 10 ~R 14 or R 20 ~R 24 The total number of carbon atoms contained in at least one of the above is 6 or more.

[0212] When n is 2, the types of substituents, the number of substituents, and the positions of bonds of the two phenylene groups may be the same or different, and when p is 2, the types of substituents, the number of substituents, and the positions of bonds of the two phenyl groups may be the same or different. 4 may be the same or different, and when u is an integer of 2 to 4, a plurality of R 3 may be the same or different. 1 and R 2 may be bonded to each other to form a ring, R 4 , R 10 ~R 14 and R 20 ~R 24 Adjacent groups may be bonded to each other to form a ring.

[0213] [ka]

[0214] In the above general formula (G4), u represents an integer of 0 to 4. It is preferable that u is 0.

[0215] Also, R 10 ~R 14 and R 20 ~R 24each independently represents hydrogen or a hydrocarbon group having 1 to 12 carbon atoms and in which the carbons form bonds only through sp3 hybrid orbitals. As the hydrocarbon group having 1 to 12 carbon atoms and in which the carbons form bonds only through sp3 hybrid orbitals, an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms are preferred. Specifically, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a isobutyl group, a tert-butyl group, a pentyl group, a isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, a isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a heptyl group, an octyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a decahydronaphthyl group, a cycloundecyl group, a cyclododecyl group, and the like can be used, with a t-butyl group, a cyclohexyl group, and a cyclododecyl group being particularly preferred.

[0216] However, R 10 ~R 14 and R 20 ~R 24 The total number of carbon atoms contained in R is 8 or more, and 10 ~R 14 or R 20 ~R 24 The total number of carbon atoms contained in at least one of the above is 6 or more.

[0217] Also, R 1 , R 2 and R 3 Each independently represents an alkyl group having 1 to 4 carbon atoms. When u is an integer of 2 to 4, multiple R 3 may be the same or different. 1 and R 2 may be bonded to each other to form a ring, R 10 ~R 14 and R 20 ~R 24 Adjacent groups may be bonded to each other to form a ring.

[0218] In the above general formulae (G2) to (G4), R 10 ~R 14 and R 20 ~R 24 are preferably each independently any one of hydrogen, a tert-butyl group, and a cyclohexyl group in order to reduce the refractive index. 10 ~R 14 At least 3 of and R 20 ~R 24 At least three of these are preferably hydrogen atoms, since this does not impair the transportability of carriers.

[0219] Also, R 10 , R 11 , R 13 , R 14 , R 20 , R 21 , R 23 and R 24 is hydrogen and R 12 and R 22 is preferably a cyclohexyl group.

[0220] Also, R 10 , R 12 , R 14 , R 20 , R 21 , R 23 and R 24 is hydrogen and R 11 and R 13 is a tert-butyl group, and R 22 is preferably a cyclohexyl group.

[0221] Also R 10 , R 12 , R 14 , R 20 , R 22 and R 24 is hydrogen and R 11 , R 13 , R 21 and R 23 is preferably a tert-butyl group.

[0222] The organic compound of one embodiment of the present invention having the above structure has a hole-transporting property and a small refractive index, and therefore is effectively used for the hole-transport layer 112. The organic compound of one embodiment of the present invention can be used as the hole-injection layer 111 by using a film in which the organic compound is mixed with an acceptor substance. An organic EL device using the organic compound has a hole-transporting layer or a hole-injection layer with a small refractive index, and therefore can be a light-emitting device with high emission efficiency, that is, high external quantum efficiency, current efficiency, and blue index. An organic EL device using the organic compound can be a light-emitting device with a long lifetime because the organic compound is a monoamine compound.

[0223] Furthermore, the organic compound can also be used as a host material. It may also be configured to form an exciplex of the electron transport material and the hole transport material by co-evaporation with the organic compound. By forming an exciplex having an appropriate emission wavelength, it is possible to realize effective energy transfer to the light emitting material and provide a light emitting device having high efficiency and good life.

[0224] Next, a method for synthesizing the above-mentioned monoamine compound will be exemplified. Note that the following is an example of the synthesis method of the present invention, and the present invention is not necessarily limited to this synthesis method.

[0225] [ka]

[0226] As shown in the synthesis scheme below, an organic compound represented by general formula (G1) can be obtained by coupling 9,9-disubstituted-9H-fluorenylamine (A) with an organic halide (X1) or (X2) in the presence of a base using a metal catalyst, a metal, or a metal compound.

[0227] [ka]

[0228] In the above synthesis scheme, Ar 1 , Ar 2 each independently represents a substituted or unsubstituted benzene ring or a substituent in which two or three benzene rings are bonded to each other, provided that Ar 1 , Ar 2 one or both of the carbon atoms have one or more hydrocarbon groups having 1 to 12 carbon atoms, the carbon atoms forming bonds only through sp3 hybrid orbitals, and Ar 1 and Ar 2 The total number of carbon atoms contained in the hydrocarbon group bonded to Ar is 8 or more, and 1 and Ar 2 The total number of carbon atoms contained in the hydrocarbon group bonded to at least one of Ar 1 or Ar 2 In the case where a plurality of linear alkyl groups having 1 or 2 carbon atoms are bonded to R as the hydrocarbon group, the linear alkyl groups may be bonded to each other to form a ring. 1 and R 2 Each independently represents an alkyl group having 1 to 4 carbon atoms. 1 and R 2 may be bonded to each other to form a ring. 3 represents an alkyl group having 1 to 4 carbon atoms, and u is an integer of 0 to 4. In addition, X represents a halogen element or a triflate group.

[0229] When the above synthesis reaction is carried out by the Buchwald-Hartwig reaction, X represents a halogen element or a triflate group. The halogen element is preferably iodine, bromine, or chlorine. In this reaction, a palladium complex or compound such as bis(dibenzylideneacetone)palladium(0) or allyl palladium chloride dimer(II) and a palladium catalyst having a ligand such as tri(tert-butyl)phosphine, di-tert-butyl(1-methyl-2,2-diphenylcyclopropyl)phosphine, or tricyclohexylphosphine coordinated thereto are used. As the base, an organic base such as sodium-tert-butoxide or an inorganic base such as cesium carbonate can be used. In addition, when a solvent is used, toluene, xylene, 1,3,5-trimethylbenzene, etc. can be used. Furthermore, by setting the reaction temperature at 120°C or higher, the reaction between an aryl group having a short-period halogen element (e.g., chlorine) and an amine proceeds in a short period of time and in high yield. Therefore, it is more preferable to use xylene or 1,3,5-trimethylbenzene, which have high heat resistance.

[0230] When the synthesis is carried out by the Ullmann reaction, X represents a halogen element. The halogen element is preferably iodine, bromine, or chlorine. Copper or a copper compound is used as the catalyst. Copper iodide (I) or copper acetate (II) is preferably used. The base may be an inorganic base such as potassium carbonate. As the solvent, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (DMPU), N-methyl-2-pyrrolidone (NMP), toluene, xylene, 1,3,5-trimethylbenzene, or the like can be used. In the Ullmann reaction, since the target product can be obtained in a shorter time and with a higher yield at a reaction temperature of 100°C or higher, it is preferable to use DMPU, NMP, or 1,3,5-trimethylbenzene, which have high boiling points. Furthermore, since the reaction temperature is more preferably 150°C or higher, it is more preferable to use DMPU.

[0231] As described above, the organic compound of general formula (G1) can be synthesized.

[0232] (Embodiment 3) In this embodiment mode, a display device using the light-emitting device described in Embodiment 1 will be described.

[0233] In this embodiment, a display device manufactured using the light-emitting device described in embodiment 1 will be described with reference to FIG. 7. FIG. 7(A) is a top view showing the display device, and FIG. 7(B) is a cross-sectional view taken along the lines AB and CD in FIG. 7(A). This display device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, for controlling light emission from the light-emitting device. Reference numeral 604 denotes a sealing substrate, 605 denotes a sealant, and the inside surrounded by the sealant 605 defines a space 607.

[0234] The lead wiring 608 is a wiring for transmitting signals input to the source line driving circuit 601 and the gate line driving circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, and the like from an FPC (flexible printed circuit) 609 serving as an external input terminal. Although only an FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the light emitting device includes not only the light emitting device itself, but also a state in which an FPC or a PWB is attached to it.

[0235] Next, the cross-sectional structure will be described with reference to Fig. 7(B) Although a driver circuit portion and a pixel portion are formed on an element substrate 610, a source line driver circuit 601 which is the driver circuit portion and one pixel in a pixel portion 602 are shown here.

[0236] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl fluoride), polyester, acrylic, or the like.

[0237] The structure of the transistor used in the pixel or the driver circuit is not particularly limited. For example, the transistor may be an inverted staggered type transistor or a staggered type transistor. In addition, the transistor may be a top-gate type transistor or a bottom-gate type transistor. The semiconductor material used for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, or the like may be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used.

[0238] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in a part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0239] Here, in addition to the transistors provided in the pixels and driver circuits, an oxide semiconductor is preferably used for semiconductor devices such as transistors used in touch sensors, which will be described later. In particular, an oxide semiconductor having a wider band gap than silicon is preferably used. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0240] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0241] Here, an oxide semiconductor that can be used in one embodiment of the present invention is described below.

[0242] Oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors other than those mentioned above. Examples of non-single-crystal oxide semiconductors include c-axis aligned crystalline oxide semiconductors (CAAC-OS), polycrystalline oxide semiconductors, nano crystalline oxide semiconductors (nc-OS), amorphous-like oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0243] CAAC-OS has a c-axis orientation and a distorted crystal structure in which multiple nanocrystals are connected in the ab-plane direction. The distortion refers to a portion where the lattice orientation changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple nanocrystals are connected.

[0244] Nanocrystals are basically hexagonal, but may be non-regular hexagonal. In addition, the lattice arrangement may be pentagonal or heptagonal due to the distortion. It is difficult to confirm clear grain boundaries in CAAC-OS even near the distortion. In other words, it is found that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is because CAAC-OS can tolerate distortion due to the lack of dense arrangement of oxygen atoms in the ab-plane direction and the change in the bond distance between atoms due to the substitution of metal elements.

[0245] CAAC-OS also tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium and oxygen (hereinafter, In layer) and a layer containing element M, zinc, and oxygen (hereinafter, (M, Zn) layer) are stacked. Note that indium and element M can be substituted for each other, and when element M in an (M, Zn) layer is substituted for indium, it can also be expressed as an (In, M, Zn) layer. When indium in an In layer is substituted for element M, it can also be expressed as an (In, M) layer.

[0246] CAAC-OS is an oxide semiconductor with high crystallinity. On the other hand, it is difficult to identify clear crystal boundaries in CAAC-OS, so it can be said that the decrease in electron mobility caused by crystal boundaries is unlikely to occur. In addition, the crystallinity of oxide semiconductors can be decreased by the introduction of impurities or the generation of defects. Therefore, CAAC-OS is not prone to impurities or defects (oxygen vacancies (V O The oxide semiconductor having the CAAC-OS has stable physical properties. Therefore, the oxide semiconductor having the CAAC-OS has high heat resistance and reliability.

[0247] The nc-OS has periodic atomic arrangement in a microscopic region (for example, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In addition, the nc-OS does not show regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is seen throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor.

[0248] Indium-gallium-zinc oxide (hereinafter, IGZO), a type of oxide semiconductor containing indium, gallium, and zinc, may have a stable structure when made into the above-mentioned nanocrystals. In particular, since IGZO tends to have difficulty in crystal growth in the air, it may be structurally more stable when made into small crystals (for example, the above-mentioned nanocrystals) rather than large crystals (here, crystals of several mm or several cm).

[0249] The a-like OS is an oxide semiconductor having a structure between the nc-OS and an amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS.

[0250] Oxide semiconductors have a variety of structures and have different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, an nc-OS, and a CAAC-OS.

[0251] As an alternative to the oxide semiconductor, a cloud-aligned composite (CAC)-OS may be used.

[0252] CAC-OS is a material in which some of the material has a conductive function and some of the material has an insulating function, and the material as a whole functions as a semiconductor. When CAC-OS is used in the active layer of a transistor, the conductive function is a function of allowing electrons (or holes) to flow as carriers, and the insulating function is a function of not allowing electrons to flow as carriers. By making the conductive function and the insulating function act in a complementary manner, it is possible to give the CAC-OS a switching function (on / off function). By separating the respective functions in CAC-OS, it is possible to maximize both functions.

[0253] The CAC-OS has a conductive region and an insulating region. The conductive region has the above-mentioned conductive function, and the insulating region has the above-mentioned insulating function. In the material, the conductive region and the insulating region may be separated at the nanoparticle level. In addition, the conductive region and the insulating region may be unevenly distributed in the material. In addition, the conductive region may be observed to be connected in a cloud shape with a blurred periphery.

[0254] In addition, in the CAC-OS, the conductive regions and the insulating regions may each be dispersed in the material with a size of 0.5 nm or more and 10 nm or less, preferably 0.5 nm or more and 3 nm or less.

[0255] In addition, the CAC-OS is composed of components having different band gaps. For example, the CAC-OS is composed of a component having a wide gap due to an insulating region and a component having a narrow gap due to a conductive region. In this configuration, when carriers are caused to flow, the carriers mainly flow in the component having the narrow gap. In addition, the component having the narrow gap acts complementarily to the component having the wide gap, and carriers also flow in the component having the wide gap in conjunction with the component having the narrow gap. Therefore, when the above-mentioned CAC-OS is used in the channel formation region of a transistor, a high current driving force, that is, a large on-current and a high field effect mobility can be obtained in the on-state of the transistor.

[0256] That is, CAC-OS can also be called a matrix composite or a metal matrix composite.

[0257] By using the above-described oxide semiconductor material for the semiconductor layer, a change in electrical characteristics can be suppressed, and a highly reliable transistor can be realized.

[0258] In addition, the transistor having the above-mentioned semiconductor layer can hold charge accumulated in a capacitance through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop a driver circuit while maintaining the gray level of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

[0259] It is preferable to provide an undercoat film in order to stabilize the characteristics of the transistor. The undercoat film can be prepared as a single layer or a multilayer structure using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The undercoat film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the undercoat film need not be provided if it is not necessary.

[0260] The FET 623 indicates one of the transistors formed in the driving circuit section 601. The driving circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. Although the present embodiment shows a driver-integrated type in which a driving circuit is formed on a substrate, this is not necessarily required, and the driving circuit may be formed externally instead of on the substrate.

[0261] In addition, the pixel section 602 is formed of a plurality of pixels including a switching FET 611, a current control FET 612, and an anode 613 electrically connected to the drain of the FET 612. However, the present invention is not limited to this, and the pixel section may be formed by combining three or more FETs and a capacitive element.

[0262] An insulator 614 is formed to cover the end of the anode 613. Here, the insulator 614 can be formed by using a positive type photosensitive acrylic.

[0263] In order to improve the covering ability of an EL layer or the like to be formed later, a curved surface having a curvature is formed at the upper end or lower end of the insulator 614. For example, when a positive type photosensitive acrylic is used as the material of the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface having a radius of curvature (0.2 μm to 3 μm). In addition, either a negative type photosensitive resin or a positive type photosensitive resin can be used as the insulator 614.

[0264] An EL layer 616 and a cathode 617 are formed on the anode 613. Here, it is desirable to use a material with a large work function as the material used for the anode 613. For example, in addition to a single layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film, a laminated structure of a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film, can be used. Note that the laminated structure has low resistance as wiring, provides good ohmic contact, and can further function as an anode.

[0265] The EL layer 616 is formed by various methods such as a deposition method using a deposition mask, an inkjet method, a spin coating method, etc. The EL layer 616 includes the configuration described in the embodiment 1. Other materials constituting the EL layer 616 may be low molecular weight compounds or high molecular weight compounds (including oligomers and dendrimers).

[0266] Furthermore, it is preferable to use a material having a small work function (such as Al, Mg, Li, Ca, or alloys or compounds thereof (MgAg, MgIn, AlLi, etc.)) as a material used for the cathode 617 formed on the EL layer 616. When the light generated in the EL layer 616 is transmitted through the cathode 617, it is preferable to use a laminate of a thin metal thin film and a transparent conductive film (ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the cathode 617.

[0267] The anode 613, the EL layer 616, and the cathode 617 form a light-emitting device.

[0268] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealant 605, a structure is formed in which a light emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. The space 607 is filled with a filler, and may be filled with an inert gas (nitrogen, argon, etc.) or a sealant. A recess is formed in the sealing substrate and a desiccant is provided therein to suppress deterioration due to the influence of moisture, which is a preferable configuration.

[0269] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also preferable that these materials are as moisture and oxygen impermeable as possible. In addition to glass and quartz substrates, materials that can be used for the sealing substrate 604 include plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic, etc.

[0270] Although not shown in Fig. 7, a protective film may be provided on the cathode. The protective film may be formed of an organic resin film or an inorganic insulating film. The protective film may be formed so as to cover the exposed portion of the sealant 605. The protective film may be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0271] The protective film can be made of a material that is difficult for impurities such as water to permeate, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0272] The protective film may be made of an oxide, a nitride, a fluoride, a sulfide, a ternary compound, a metal, a polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium 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, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, or the like; a nitride containing titanium and aluminum; an oxide containing titanium and aluminum; an oxide containing aluminum and zinc; a sulfide containing manganese and zinc; a sulfide containing cerium and strontium; an oxide containing erbium and aluminum; an oxide containing yttrium and zirconium, or the like.

[0273] The protective film is preferably formed using a film formation method with good step coverage. One such method is the atomic layer deposition (ALD) method. It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the processed member when forming the protective film.

[0274] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces with complex uneven shapes, as well as on the top, side, and back surfaces of a touch panel.

[0275] The light-emitting device in this embodiment uses the light-emitting device described in Embodiment 1, and therefore a display device with good characteristics can be obtained. Specifically, the light-emitting device described in Embodiment 1 has a long life, and therefore a display device with good reliability can be obtained. In addition, the display device using the light-emitting device described in Embodiment 1 has good emission efficiency, and therefore a light-emitting device with low power consumption can be obtained.

[0276] An example of a full-color light-emitting device is shown in Fig. 8, in which a light-emitting device that emits blue light is formed and a color conversion layer is provided. Fig. 8(A) shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral section 1042, a pixel section 1040, a driving circuit section 1041, first electrodes 1024R, 1024G, and 1024B of the light-emitting device, a partition wall 1025, an EL layer 1028, a cathode 1029 of the light-emitting device, a sealing substrate 1031, a sealant 1032, and the like.

[0277] 8(A), the color conversion layers (red color conversion layer 1034R, green color conversion layer 1034G) are provided on a transparent base material 1033. A black matrix 1035 may also be provided. Transparent base material 1033 provided with the color conversion layers and black matrix is ​​aligned and fixed to substrate 1001. The color conversion layers and black matrix 1035 may be covered with an overcoat layer 1036.

[0278] 8B shows an example in which color conversion layers (red color conversion layer 1034R and green color conversion layer 1034G) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. In this manner, the colored layers may be provided between the substrate 1001 and the sealing substrate 1031.

[0279] In the light-emitting device described above, the light-emitting device has a structure (bottom emission type) in which light is extracted to the substrate 1001 side on which the FET is formed, but the light-emitting device may have a structure (top emission type) in which light is extracted to the sealing substrate 1031 side. A cross-sectional view of a top emission type light-emitting device is shown in FIG. 9. In this case, a substrate that does not transmit light can be used as the substrate 1001. The process is performed in the same manner as the bottom emission type light-emitting device until a connection electrode that connects the FET and the anode of the light-emitting device is formed. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may play a role of planarization. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0280] The first electrodes 1024R, 1024G, and 1024B of the light-emitting device are anodes here, but may be cathodes. In addition, in the case of a top-emission type light-emitting device as shown in Fig. 9, it is preferable that the first electrodes are reflective electrodes. The EL layer 1028 is configured to have a device structure that can emit blue light.

[0281] In the top emission structure as shown in FIG. 9, sealing can be performed with a sealing substrate 1031 provided with color conversion layers (red color conversion layer 1034R, green color conversion layer 1034G). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The color conversion layers (red color conversion layer 1034R, green color conversion layer 1034G) and the black matrix may be covered with an overcoat layer. Note that a light-transmitting substrate is used for the sealing substrate 1031. The color conversion layers (red color conversion layer 1034R, green color conversion layer 1034G) may be provided directly on the cathode 1029 (or on a protective film provided on the cathode 1029).

[0282] The insulating layer 1038 serves as a protective layer to prevent impurities from diffusing into the light emitting device. The insulating layer 1038 can be made of an oxide, a nitride, a fluoride, a sulfide, a ternary compound, a metal, a polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium 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, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, or the like; a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, an oxide containing yttrium and zirconium, or the like can be used. Silicon nitride, silicon oxide, silicon nitride oxide, or the like is preferable. The insulating layer 1038 is not necessarily formed.

[0283] The space 1030 may be filled with a resin. The resin preferably has a refractive index of 1.4 to 2.0, more preferably 1.7 to 1.9. The presence of a layer with a relatively high refractive index between the transparent electrode and the color conversion layer reduces light loss due to the thin film mode, and a more efficient light-emitting device can be obtained.

[0284] In the above configuration, the EL layer may have a plurality of light-emitting layers or a single light-emitting layer. For example, the EL layer may be combined with the above-mentioned tandem light-emitting device configuration to provide a single light-emitting device with a plurality of EL layers sandwiched between charge generating layers, and each EL layer may have a single or multiple light-emitting layers.

[0285] In top-emission type light-emitting devices, the application of a microcavity structure is suitable. A light-emitting device having a microcavity structure can be obtained by using a reflective electrode as the anode and a semi-transmissive / semi-reflective electrode as the cathode. At least an EL layer is present between the reflective electrode and the semi-transmissive / semi-reflective electrode, and at least a light-emitting layer that becomes the light-emitting region is present.

[0286] The reflectance of the reflective electrode to visible light is 40% to 100%, preferably 70% to 100%, and the resistivity is 1×10 -2 The semi-transmitting and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1×10 -2 It is assumed that the film has a resistance of less than Ωcm.

[0287] Light emitted from a light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transmissive and semi-reflective electrode, causing resonance.

[0288] In this light-emitting device, the optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode can be changed by changing the thickness of the transparent conductive film, the above-mentioned composite material, the carrier transport material, etc. This makes it possible to intensify the light of resonating wavelengths and attenuate the light of non-resonating wavelengths between the reflective electrode and the semi-transmissive / semi-reflective electrode.

[0289] In addition, since the light reflected by the reflective electrode and returned (first reflected light) causes significant interference with the light (first incident light) that is directly incident on the semi-transmissive and semi-reflective electrode from the light-emitting layer, it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number equal to or greater than 1, and λ is the wavelength of the emitted light to be amplified). By adjusting the optical distance, the phase of the first reflected light and the first incident light can be aligned, thereby further amplifying the light emitted from the light-emitting layer.

[0290] In the above configuration, the EL layer may have a plurality of light-emitting layers or a single light-emitting layer. For example, the EL layer may be combined with the above-mentioned tandem light-emitting device configuration to provide a single light-emitting device with a plurality of EL layers sandwiched between charge generating layers, and each EL layer may have a single or multiple light-emitting layers.

[0291] (Embodiment 4) In this embodiment, an example of an electronic device including a light-emitting device according to one embodiment of the present invention will be described. The light-emitting device according to one embodiment of the present invention has low power consumption and high reliability. As a result, the electronic device described in this embodiment can be an electronic device with low power consumption and high reliability.

[0292] Examples of electronic devices to which the light-emitting devices are applied include television sets (also called televisions or television 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, large game machines such as pachinko machines, etc. Specific examples of these electronic devices are shown below.

[0293] 10A shows an example of a television set. In the television set, a display portion 7103 is incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7105. Images can be displayed by the display portion 7103, and the display portion 7103 has light-emitting devices arranged in a matrix.

[0294] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control 7110. Using operation keys 7109 provided on the remote control 7110, the channel and volume can be controlled, and an image displayed on the display portion 7103 can be operated. The remote control 7110 may be provided with a display portion 7107 that displays information output from the remote control 7110.

[0295] The television device is configured to include a receiver, a modem, etc. The receiver can receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it is also possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0296] FIG. 10B1 shows a computer, which includes a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that this computer is manufactured by using light-emitting devices arranged in a matrix for the display portion 7203. The computer in FIG. 10B1 may have a form as shown in FIG. 10B2. The computer in FIG. 10B2 is provided with a second display portion 7210 instead of the keyboard 7204 and the pointing device 7206. The second display portion 7210 is a touch panel type, and input can be performed by operating the display for input displayed on the second display portion 7210 with a finger or a dedicated pen. The second display portion 7210 can display not only the display for input, but also other images. The display portion 7203 may also be a touch panel. The two screens are connected by a hinge, which can prevent the screens from being scratched or damaged during storage or transportation.

[0297] 10C shows an example of a mobile terminal. The mobile phone includes a display portion 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone includes the display portion 7402 manufactured using the light-emitting device described in Embodiment 1.

[0298] 10C can be configured so that information can be input by touching the display portion 7402 with a finger or the like. In this case, operations such as making a call or composing an e-mail can be performed by touching the display portion 7402 with a finger or the like.

[0299] The screen of the display unit 7402 has three main modes. The first is a display mode that is mainly for displaying images, the second is an input mode that is mainly for inputting information such as characters, and the third is a display + input mode that combines the display mode and the input mode.

[0300] For example, when making a call or composing an e-mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and the character input operation may be performed by inputting characters displayed on the screen. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402.

[0301] In addition, by providing a detection device having a sensor for detecting tilt, such as a gyro or an acceleration sensor, inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined and the screen display of the display portion 7402 can be automatically switched.

[0302] The screen mode can be switched by touching the display portion 7402 or by operating operation buttons 7403 on the housing 7401. The mode can also be switched depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display portion is moving image data, the mode is switched to the display mode, and if it is text data, the mode is switched to the input mode.

[0303] In addition, in the input mode, a signal detected by an optical sensor of the display portion 7402 may be detected, and if there is no input by a touch operation on the display portion 7402 for a certain period of time, the screen mode may be controlled to be switched from the input mode to the display mode.

[0304] The display portion 7402 can also function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger to capture an image of a palm print, a fingerprint, or the like. In addition, finger veins, palm veins, or the like can be captured by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light for the display portion.

[0305] Note that the structure described in this embodiment mode can be used by appropriately combining the structures described in any of Embodiment Modes 1 to 3.

[0306] As described above, the light-emitting device according to one embodiment of the present invention has a very wide range of application and can be used in electronic devices in a variety of fields. By using the light-emitting device according to one embodiment of the present invention, electronic devices with low power consumption can be obtained.

[0307] FIG. 11(A) is a schematic diagram showing an example of a cleaning robot.

[0308] The cleaning robot 5100 has a display 5101 arranged on the top surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and an operation button 5104. Although not shown, the bottom surface of the cleaning robot 5100 is provided with tires, a suction port, and the like. The cleaning robot 5100 also has various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezoelectric sensor, an optical sensor, and a gyro sensor. The cleaning robot 5100 also has wireless communication means.

[0309] The cleaning robot 5100 can move by itself, detect dirt 5120, and suck up the dirt from a suction port provided on the bottom surface.

[0310] In addition, the cleaning robot 5100 can analyze the image captured by the camera 5102 and determine the presence or absence of obstacles such as walls, furniture, steps, etc. Furthermore, when an object that may become entangled in the brush 5103, such as a wire, is detected by image analysis, the rotation of the brush 5103 can be stopped.

[0311] The remaining battery level, the amount of sucked up dirt, etc. can be displayed on the display 5101. The route traveled by the cleaning robot 5100 may be displayed on the display 5101. The display 5101 may be a touch panel, and an operation button 5104 may be provided on the display 5101.

[0312] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when he or she is away from home. Also, the display on the display 5101 can be confirmed on a portable electronic device such as a smartphone.

[0313] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0314] The robot 2100 shown in FIG. 11(B) includes a computing device 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.

[0315] The microphone 2102 has a function of detecting the user's voice, environmental sounds, etc. The speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0316] The display 2105 has a function of displaying various information. The robot 2100 can display information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a removable information terminal, and by installing it in a fixed position on the robot 2100, charging and data transfer are possible.

[0317] The upper camera 2103 and the lower camera 2106 have a function of capturing images of the surroundings of the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of an obstacle in the moving direction when the robot 2100 moves forward using the moving mechanism 2108. The robot 2100 can recognize the surrounding environment and move safely using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light-emitting device of one embodiment of the present invention can be used for the display 2105.

[0318] 11C is a diagram showing an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, a connection terminal 5006, a sensor 5007 (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared ray), a microphone 5008, a display unit 5002, a support unit 5012, and earphones 5013.

[0319] The light-emitting device of one embodiment of the present invention can be used for the display portion 5001 and the display portion 5002 .

[0320] The light-emitting device of one embodiment of the present invention can be mounted on a windshield or dashboard of an automobile. Fig. 12 shows an embodiment in which the light-emitting device of one embodiment of the present invention is used on a windshield or dashboard of an automobile. Display regions 5200 to 5203 are displays provided using the light-emitting device of one embodiment of the present invention.

[0321] A display region 5200 and a display region 5201 are display devices provided on the windshield of an automobile and equipped with a light-emitting device according to one embodiment of the present invention. The light-emitting device can be a so-called see-through display device in which the other side can be seen through by forming an anode and a cathode using light-transmitting electrodes. If the display is in a see-through state, the display device can be installed on the windshield of an automobile without interfering with visibility. Note that when a transistor for driving the display device is provided, a light-transmitting transistor such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor is preferably used.

[0322] A display area 5202 is a display device equipped with a light-emitting device according to one embodiment of the present invention, which is provided in a pillar portion. By displaying an image from an imaging means provided in the vehicle body in the display area 5202, the view blocked by the pillar can be complemented. Similarly, a display area 5203 provided in the dashboard can complement the view blocked by the vehicle body by displaying an image from an imaging means provided outside the vehicle, thereby compensating for blind spots and improving safety. By displaying an image to complement the invisible parts, safety can be confirmed more naturally and without discomfort.

[0323] The display area 5203 can also provide various other information such as navigation information, speed, and number of revolutions. The display items and layout can be changed as appropriate according to the user's preferences. Note that this information can also be provided in the display areas 5200 to 5202. The display areas 5200 to 5203 can also be used as lighting devices.

[0324] 13A and 13B show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 has a housing 5151, a display area 5152, and a bending portion 5153. Fig. 13A shows the mobile information terminal 5150 in an unfolded state. Fig. 13B shows the mobile information terminal in a folded state. Although the mobile information terminal 5150 has a large display area 5152, it is compact and highly portable when folded.

[0325] The display area 5152 can be folded in half by the bending portion 5153. The bending portion 5153 is composed of an expandable member and a plurality of support members, and when folding, the expandable member stretches. The bending portion 5153 is folded with a curvature radius of 2 mm or more, preferably 3 mm or more.

[0326] Note that the display region 5152 may be a touch panel (input / output device) equipped with a touch sensor (input device). The light-emitting device of one embodiment of the present invention can be used for the display region 5152.

[0327] 14(A) to 14(C) show a foldable portable information terminal 9310. Fig. 14(A) shows the portable information terminal 9310 in an unfolded state. Fig. 14(B) shows the portable information terminal 9310 in a state in which it is changing from one of the unfolded state and the folded state to the other. Fig. 14(C) shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in a folded state, and has excellent viewability of the display due to a seamless wide display area in an unfolded state.

[0328] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display panel 9311 can be reversibly transformed from an unfolded state of the mobile information terminal 9310 to a folded state by bending the two housings 9315 via the hinges 9313. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311. EXAMPLES

[0329] <Synthesis example> In this embodiment, a method for synthesizing the low refractive index hole transporting material described in Embodiment 2 will be described.

[0330] First, we will explain the detailed synthesis method of N,N-bis(4-cyclohexylphenyl)-9,9,-dimethyl-9H-fluoren-2-amine (abbreviation: dchPAF). The structure of dchPAF is shown below.

[0331] [ka]

[0332] <Step 1: Synthesis of N,N-bis(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: dchPAF)> In a three-neck flask, 10.6 g (51 mmol) of 9,9-dimethyl-9H-fluoren-2-amine, 18.2 g (76 mmol) of 4-cyclohexyl-1-bromobenzene, 21.9 g (228 mmol) of sodium-tert-butoxide, and 255 mL of xylene were placed, and the flask was degassed under reduced pressure, and then replaced with nitrogen. This mixture was heated to about 50°C and stirred. Here, 370 mg (1.0 mmol) of allyl palladium chloride dimer (II) (abbreviation: [(Allyl)PdCl]2) and 1660 mg (4.0 mmol) of di-tert-butyl(1-methyl-2,2-diphenylcyclopropyl)phosphine (abbreviation: cBRIDP (registered trademark)) were added, and this mixture was heated at 120°C for about 5 hours. Thereafter, the temperature of the flask was returned to about 60°C, and about 4 mL of water was added to precipitate a solid. The precipitated solid was filtered off. The filtrate was concentrated, and the resulting solution was purified by silica gel column chromatography. The resulting solution was concentrated to obtain a thick toluene solution. This toluene solution was dropped into ethanol to cause reprecipitation. The precipitate was filtered at about 10°C, and the resulting solid was dried under reduced pressure at about 80°C to obtain 10.1 g of the target white solid in a yield of 40%. The synthesis scheme of dchPAF in step 1 is shown below.

[0333] [ka]

[0334] The white solid obtained in step 1 was analyzed by nuclear magnetic resonance spectroscopy ( 1 The results of the analysis by H-NMR are shown below. From this, it was found that dchPAF was successfully synthesized in this synthesis example.

[0335] 1H-NMR.δ(CDCl3):7.60(d,1H,J=7.5Hz),7.53(d,1H,J=8.0Hz),7.37(d,2H,J=7 .5Hz),7.29(td,1H,J=7.5Hz,1.0Hz),7.23(td,1H,J=7.5Hz,1.0Hz),7.19(d,1H ,J=1.5Hz),7.06(m,8H),6.97(dd,1H,J=8.0Hz,1.5Hz),2.41-2.51(brm,2H),1. 79-1.95(m,8H),1.70-1.77(m,2H),1.33-1.45(brm,14H),1.19-1.30(brm,2H).

[0336] Similarly, organic compounds represented by the following structural formulas (101) to (111) were synthesized.

[0337] [ka]

[0338] [ka]

[0339] Nuclear magnetic resonance spectroscopy of the above organic compounds ( 1 The results of the analysis by H-NMR are shown below.

[0340] Structural formula (101) N-[(4'-cyclohexyl)-1,1'-biphenyl-4yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: chBichPAF) 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.57(d,1H,J=7.5Hz),7.51(d,2H,J =8.0Hz),7.46(d,2H,J=7.5Hz),7.38(d,1H,J=7.5Hz),7.30(td,1H,J=7.0Hz ,1.5Hz),7.20-7.28(m,6H),7.01-7.18(m,7H),2.43-2.57(brm,2H),1.81-1 .96(m,8H),1.71-1.79(brm,2H),1.34-1.50(brm,14H),1.20-1.32(brm,2H).

[0341] Structural formula (102) N,N-bis(4-cyclohexylphenyl)-N-(spiro[cyclohexane-1,9'[9H]fluoren]-2'-yl)amine (abbreviation: dchPASchF) 1 H-NMR.δ(CDCl3):7.60-7.65(m,2H),7.54(d,1H,J=8.0Hz),7.28-7.35(m,2H),7.19-7.24(t,1H,J=7.5Hz),7.02-7.12(m,8H),6.97-7.22 (d,1H,J=8.0Hz),2.40-2.52(brm,2H),1.79-1.95(m,10H),1.63-1.78(m,9H),1.55-1.63(m,1H),1.32-1.46(m,8H),1.18-1.30(brm,2H).

[0342] Structural formula (103) N-[(4'-cyclohexyl)-1,1'-biphenyl-4-yl]-N-(4-cyclohexylphenyl)-N-(spiro[cyclohexane-1,9'-[9H]-fluoren]-2'-yl)-amine (abbreviation: chBichPASchF) 1H-NMR.δ(CDCl3):7.65(d,2H,J=8.0Hz),7.58(d,1H,J=8.0Hz),7.51(d,2H,J=8.5Hz),7 .46(m,2H),7.39(d,1H,1.5Hz),7.32(t,1H,J=8.0Hz),7.21-7.38(m,3H),7.14-7.18(m, 2H),7.08-7.14(m,4H),7.06(dd,1H,J=8.0Hz,1.5Hz),2.43-2.57(brm,2H),1.80-1.97 (m,10H),1.64-1.80(m,9H),1.56-1.64(m,1H),1.34-1.53(m,8H),1.20-1.32(brm,2H).

[0343] Structural formula (104) N-(4-cyclohexylphenyl)-N,N-bis(spiro[cyclohexane-1,9'-[9H]-fluoren]-2'-yl)amine (abbreviation: SchFB1chP) 1 H-NMR.δ(CDCl3):7.64(t,4H,J=8.0Hz),7.59(d,2H,J=8.5Hz),7.39(brs,2H),7.33(t,2H,J=7.5Hz),7.20-7.25(m,2H),7.12(brs ,4H),7.08(d,2H,J=8.0Hz),2.44-2.52(brm,1H),1.63-1.97(m,23H),1.50-1.61(m,2H),1.34-1.48(m,4H),1.20-1.32(brm,1H).

[0344] Structural formula (105) N-[(3',5'-ditertiarybutyl)-1,1'-biphenyl-4-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBuBichPAF) 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.57(d,1H,J=8.0Hz),7.44-7.49(m,2H) ,7.37-7.42(m,4H),7.31(td,1H,J=7.5Hz,2.0Hz),7.23-7.27(m,2H),7.15-7.19( m,2H),7.08-7.14(m,4H),7.05(dd,1H,J=8.0Hz,2.0Hz),2.43-2.53(brm,1H),1. 81-1.96(m,4H),1.75(d,1H,J=12.5Hz),1.32-1.48(m,28H),1.20-1.31(brm,1H).

[0345] Structural formula (106) N,N-bis(3',5'-ditertiarybutyl-1,1'-biphenyl-4-yl)-9,9,-dimethyl-9H-fluoren-2-amine (abbreviation: dmmtBuBiAF) 1 H-NMR.δ(CDCl3):7.66(d,1H,J=7.5Hz),7.62(d,1H,J=8.0Hz),7.51(d,4H,J=8.5Hz),7.38-7.44(m, 7H),7.26-7.35(m,3H),7.20-7.25(m,4H),7.13(dd,1H,J=8.0Hz,1.5Hz),1.45(s,6H),1.39(s,36H).

[0346] Structural formula (107) N-(3,5-ditertiarybutylphenyl)-N-(3',5',-ditertiarybutyl-1,1'-biphenyl-4-yl)-9,9,-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBuBimmtBuPAF) 1 H-NMR.δ(CDCl3):7.64(d,1H,J=7.5Hz),7.57(d,1H,J=8.0Hz),7.48(d,2H,J=8.0Hz),7.43(m,2H),7.39(m,2H) ,7.31(td,1H,J=6.0Hz,1.5Hz),7.15-7.25(m,4H),6.97-7.02(m,4H),1.42(s,6H),1.38(s,18H),1.25(s,18H).

[0347] Structural formula (108) N,N-bis(4-cyclohexylphenyl)-9,9-dipropyl-9H-fluoren-2-amine (abbreviation: dchPAPrF) 1 H-NMR.δ(CDCl3):7.58(m,1H),7.51(d,1H,J=8.0Hz),7.28(t,2H,J=7.5Hz),7.19-7.24(m,1H),7.11(d,1H,J=1.5Hz),7.00-7.19(m,8H ),6.97(dd,1H,J=8.0Hz,1.5Hz),2.40-2.50(brm,2H),1.70-1.94(m,14H),1.33-1.46(m,8H),1.18-1.30(brm,2H),0.60-0.78(m,10H).

[0348] Structural formula (109) N-[(3',5'-dicyclohexyl)-1,1'-biphenyl-4-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmchBichPAF) 1 H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.57(d,1H,J=8.5Hz),7.46(d,2H,J=8.5 Hz),7.39(d,1H,J=7.5Hz),7.31(td,1H,J=7.5Hz,1.5Hz),7.21-7.28(m,4H),7.07 -7.18(m,6H),7.02-7.06(m,1H),7.01(s,1H),2.44-2.57(brm,3H),1.89-1.96(m, 6H),1.81-1.88(m,6H),1.71-1.78(m,3H),1.34-1.53(m,18H),1.20-1.32(m,3H).

[0349] Structural formula (110) N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF) 1H-NMR (300MHz, CDCl3): δ=7.63(d,J=6.6Hz,1H),7.58(d,J=8.1Hz,1H),7.4 2-7.37(m,4H),7.36-7.09(m,14H),2.55-2.39(m,1H),1.98-1.20(m,51H).

[0350] Structural formula (111) N-(4-cyclododecylphenyl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: CdoPchPAF) 1 H-NMR (300MHz, CDCl3): δ=7.61(d,J=6.6Hz,1H),7.53(d,J=8.1Hz,1H),7.37(d,J=7.5Hz,1H),7 .33-7.17(m,3H),7.12-6.95(m,9H),2.77-2.66(m,1H),2.52-2.39(m,1H),1.96-1.26(m,37H).

[0351] 15 to 26 show the results of measuring the refractive index of the above 12 materials using a spectroscopic ellipsometer (M-2000U manufactured by J.A. Woollam Japan). Note that Fig. 15 shows data on dchPAF, Fig. 16 shows data on chBichPAF, Fig. 17 shows data on dchPASchF, Fig. 18 shows data on chBichPASchF, Fig. 19 shows data on SchFB1chP, Fig. 20 shows data on mmtBuBichPAF, Fig. 21 shows data on dmmtBuBiAF, Fig. 22 shows data on mmtBuBimmtBuPAF, Fig. 23 shows data on dchPAPrF, Fig. 24 shows data on mmchBichPAF, Fig. 25 shows data on mmtBumTPchPAF, and Fig. 26 shows data on CdoPchPAF. For the measurements, a film of about 50 nm was formed by vacuum deposition of the material of each layer on a quartz substrate. In addition, the figure shows the refractive index of ordinary light, n, Ordinary, and the refractive index of extraordinary light, n, Extra-ordinary.

[0352] Thus, it was found that these organic compounds are materials with low refractive index. EXAMPLES

[0353] This example shows the results of calculating the amount of light reaching the color conversion layer by simulation for a light-emitting device 1 of one embodiment of the present invention, which has a small refractive index of a hole-transport layer, and a comparative light-emitting device 1, which has a normal refractive index.

[0354] The calculation was performed using an organic device simulator (semiconducting emissive thin film optics simulator: setfos; Cybernet Systems Co., Ltd.). The light-emitting region was fixed at the center of the light-emitting layer, and the refractive index of the organic layer was assumed to be 1.6 for materials with low refractive index and 1.9 for materials with normal refractive index, and no wavelength dispersion was assumed. The film thickness of each layer was optimized so that the blue index (BI) was maximized when the refractive index of the color conversion layer was 1. The light emission was assumed to have a spectrum as shown in Figure 27. The light-emitting device was a top-emission type light-emitting device that extracts light from the cathode side, and the film thickness of the hole transport layer was adjusted so that the total optical path length between the reflective electrode on the anode side and the cathode was an integer multiple of λ / 2. The calculation was performed assuming that QDs were used for the color conversion layer, and taking into account quenching due to the Purcell effect. The stacked structure of the light-emitting device used in the calculation is shown in the table below.

[0355] [Table 1]

[0356] The refractive index and extinction coefficient of Ag, ITSO, and Ag:Mg were determined from the physical properties of the materials.

[0357] Under the above conditions, we calculated the change in the amount of light that reaches the color conversion layer when the refractive index of the color conversion layer is changed. The amount of light that reaches the color conversion layer was calculated from the light extraction efficiency in a device structure with no absorption in the color conversion layer and the sum of the guide modes in the color conversion layer. The results are shown in Figure 28.

[0358] From Figure 28, we can see that by decreasing the refractive index of the hole transport layer, the amount of light that reaches the color conversion layer increases within the practical range of the refractive index of the color conversion layer. Increasing the amount of light that reaches the color conversion layer means that more excitation light reaches the color conversion layer, allowing more QDs to be excited.

[0359] (Reference example) In this reference example, a comparison will be made between a light emitting device using the low refractive index material described in the embodiment and a light emitting device not using the material. The structural formula of the organic compound used in this reference example is shown below.

[0360] [ka]

[0361] (Method of fabricating light-emitting device 1) First, a silver (Ag) film was formed on a glass substrate by sputtering to a thickness of 100 nm as a reflective electrode, and then an indium tin oxide containing silicon oxide (ITSO) film was formed by sputtering to a thickness of 10 nm as a transparent electrode to form a first electrode 101. The electrode area was 4 mm 2 (2mm x 2mm).

[0362] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0363] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0364] Next, the substrate on which the first electrode 101 was formed was fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed faced downward. N,N-bis(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: dchPAF) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) were co-deposited on the first electrode 101 by a deposition method to a thickness of 10 nm at a weight ratio of 1:0.05 (=dchPAF:OCHD-001) to form a hole injection layer 111.

[0365] On the hole injection layer 111, dchPAF was evaporated to a thickness of 125 nm to form a hole transport layer 112.

[0366] Next, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated onto the hole transport layer 112 to a thickness of 10 nm to form an electron blocking layer.

[0367] Thereafter, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (iii) and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (iv) were co-deposited to a thickness of 25 nm in a weight ratio of 1:0.015 (=αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form the light-emitting layer 113.

[0368] Thereafter, 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN) represented by the above structural formula (v) and 8-quinolinolato-lithium (abbreviation: Liq) represented by the above structural formula (vi) were co-deposited to a thickness of 30 nm in a weight ratio of 1:1 (=ZADN:Liq) to form an electron transport layer 114.

[0369] After the formation of the electron transport layer 114, Liq was deposited to a thickness of 1 nm to form the electron injection layer 115, and finally, silver (Ag) and magnesium (Mg) were co-deposited to a volume ratio of 10:1 and a film thickness of 15 nm to form the second electrode 102, thereby producing the light-emitting device 1. The second electrode 102 is a semi-transmissive / semi-reflective electrode having a function of reflecting light and a function of transmitting light, and this light-emitting device is a top-emission type device that extracts light from the second electrode 102. In addition, 1,3,5-tri(dibenzothiophene-4-yl)-benzene (abbreviation: DBT3P-II) represented by the above structural formula (vii) was deposited to a thickness of 70 nm on the second electrode 102 to improve the light extraction efficiency.

[0370] (Method of manufacturing light-emitting device 2) Light-emitting device 2 was fabricated in the same manner as light-emitting device 1, except that dchPAF used in the hole injection layer and hole transport layer of light-emitting device 1 was changed to N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (viii) and the thickness of the hole transport layer was changed to 110 nm.

[0371] The device structures of light-emitting device 1 and light-emitting device 2 are summarized in the table below.

[0372] [Table 2]

[0373] Note that dchPAF is a material with a refractive index of 1.75 or less for light with a wavelength of 467 nm, while other organic compounds are substances with a refractive index of more than 1.75 for light with a wavelength of 467 nm. The results of measuring the refractive index of dchPAF and PCBBiF are shown in Figure 35.

[0374] When anisotropy occurs in a material, the refractive index for ordinary light (ordinary refractive index) and the refractive index for extraordinary light (extra-ordinary refractive index) may differ. When the thin film to be measured is in such a state, anisotropy analysis can be performed to separate the ordinary refractive index and the extraordinary refractive index and calculate each refractive index. In this specification, when the measured material has both an ordinary refractive index and an extraordinary refractive index, the ordinary refractive index is used as the index.

[0375] The above light-emitting devices were sealed with a glass substrate in a nitrogen-atmosphere glove box to prevent the light-emitting devices from being exposed to the atmosphere (a UV-curable sealant was applied around the elements, UV was irradiated only on the sealant without irradiating the light on the light-emitting devices, and heat-treated at 80°C for 1 hour under atmospheric pressure). The initial characteristics of these light-emitting devices were then measured.

[0376] The luminance-current density characteristics of light-emitting device 1 and light-emitting device 2 are shown in Fig. 29, the current efficiency-luminance characteristics in Fig. 30, the luminance-voltage characteristics in Fig. 31, the current-voltage characteristics in Fig. 32, the blue index-luminance characteristics in Fig. 33, and the emission spectra in Fig. 34. 2 The main characteristics in this region are shown in Table 3. The luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0377] [Table 3]

[0378] 29 to 34 and Table 3 show that in the blue light-emitting region, light-emitting device 1 using a material with a refractive index of 1.75 or less exhibits better current efficiency and blue index than light-emitting device 2. By combining such a light-emitting device with a color conversion layer, a light-emitting device with good efficiency can be obtained. [Explanation of symbols]

[0379] 100 Substrates 101 First electrode 102 Second electrode 103 EL layer 111 Hole injection layer 112 Hole transport layer 113 Light-emitting layer 113-1 Emitting layer 113-2 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 200 Insulator 201 First electrode 201B First electrode 201G First electrode 201R First electrode 201W First electrode 202 EL layer 203 Second electrode 204 Protective layer 205B Structures with light scattering function 205G Color conversion layer 205R Color conversion layer 205W Color Conversion Layer 205 Color Conversion Layer 206 Black Matrix 207 Light Emitting Devices 207B First Light Emitting Device 207G Second Light Emitting Device 207R Third Light Emitting Device 207W 4th Light Emitting Device 208 pixels 208B First pixel 208G Second Pixel 208R The third pixel 208W 4th Pixel 209 Optical distance 210G Means of providing directionality 210R Means of imparting directionality 215B Color Filter 225R Color Filter 225G Color Filter 225B Color Filter 501 Anode 502 Cathode 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 Anode 614 Insulation 616 EL layer 617 Cathode 618 Light Emitting Devices 623 FET 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 1024R First electrode 1024G First electrode 1024B First electrode 1025 Bulkhead 1028 EL layer 1029 Cathode 1030 Space 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red color conversion layer 1034G Green color conversion layer 1035 Black Matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 Pixel section 1041 Drive circuit section 1042 Periphery 2100 Robot 2110 Arithmetic equipment 2101 Illuminance sensor 2102 Microphone 2103 Upper Camera 2104 Speaker 2105 Display 2106 Lower Camera 2107 Obstacle Sensor 2108 Moving mechanism 5000 cabinet 5001 Display section 5002 Display section 5003 Speaker 5004 LED Lamp 5006 Connection terminal 5007 Sensor 5008 Microphone 5012 Support part 5013 Earphones 5100 Cleaning robot 5101 Display 5102 Camera 5103 Brush 5104 Operation button 5150 Portable Information Terminal 5151 Case 5152 Display area 5153 Bend 5120 Garbage 5200 display area 5201 Display area 5202 Display area 5203 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 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 9310 Mobile Information Terminal 9311 Display Panel 9313 Hinge 9315 Case

Claims

1. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a light-emitting layer between an anode and a cathode, a layer containing a first organic compound having a refractive index of 1.75 or less for light having a wavelength of 467 nm (excluding the case where the first organic compound is a compound represented by the following formula [2]) between the anode and the light-emitting layer, the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 1】

2. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a hole injection layer and a light-emitting layer between an anode and a cathode, the hole injection layer is provided in contact with the anode, the hole injection layer contains a first organic compound having a refractive index of 1.75 or less with respect to light having a wavelength of 467 nm (excluding the case where the first organic compound is a compound represented by the following formula [2]), the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 2】

3. In claim 1 or 2, the first organic compound is a monoamine compound having a first aromatic ring, a second aromatic ring and a third aromatic ring, the first aromatic ring, the second aromatic ring and the third aromatic ring are bonded to a nitrogen atom of the monoamine compound; A light-emitting device comprising an organic compound in which the ratio of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 23% or more and 55% or less.

4. In claim 1 or 2, The light-emitting device, wherein the first organic compound is an organic compound represented by the following general formula (G1): 【Chemistry 3】 (In the above general formula (G1), Ar １ , Ar ２ each independently represents a benzene ring or a substituent in which two or three benzene rings are bonded to each other, provided that Ar １ , Ar ２ one or both of have one or more hydrocarbon groups having 1 to 12 carbon atoms in which carbon is bonded only through sp3 hybrid orbitals, and Ar １ and Ar ２ The total number of carbon atoms contained in the hydrocarbon group bonded to Ar is 8 or more, and １ and Ar ２ The total number of carbon atoms contained in the hydrocarbon group bonded to at least one of Ar １ Or Ar ２ In the case where a plurality of linear alkyl groups having 1 or 2 carbon atoms are bonded to R as the hydrocarbon group, the linear alkyl groups may be bonded to each other to form a ring. １ and R ２ Each independently represents an alkyl group having 1 to 4 carbon atoms. １ and R ２ may be bonded to each other to form a ring. ３ represents an alkyl group having 1 to 4 carbon atoms, and u is an integer of 0 to 4.

5. In claim 1 or claim 2, The light-emitting device, wherein the first organic compound is an organic compound represented by the following general formula (G2): 【Chemistry 4】 (In the above general formula (G2), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms, R 4 and R 5 each independently represent either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbons form bonds only through sp3 hybrid orbitals. The total number of carbons contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and R 10 to R 14 or R 20 to R 24 The total number of carbon atoms contained in at least one of is 6 or more. n, m, p, and r each independently represent 1 or 2, and s, t, and u each independently represent an integer of 0 to 4. n+p and m+r each independently represent 2 or 3. When n is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenylene groups may be the same or different, when m is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenylene groups may be the same or different, when p is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenyl groups may be the same or different, and when r is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenyl groups may be the same or different. When s is an integer of 2 to 4, the multiple R 4s may be the same or different, when t is an integer of 2 to 4, the multiple R 5s may be the same or different, and when u is an integer of 2 to 4, the multiple R 3s may be the same or different. When R 1 and R 2 may be bonded to each other to form a ring, and adjacent groups of R 4 , R 5 , R 10 to R 14 and R 20 to R 24 may be bonded to each other to form a ring.

6. In claim 5, A light-emitting device, wherein t is 0.

7. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a light-emitting layer between an anode and a cathode, a layer containing a first organic compound having a refractive index of 1.75 or less for light having a wavelength of 467 nm between the anode and the light-emitting layer; The first organic compound is an organic compound represented by the following general formula (G3): the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 5】 (In the above general formula (G3), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms, and R 4 represents hydrogen or an alkyl group having 1 to 3 carbon atoms. R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbons form bonds only through sp3 hybrid orbitals. However, the total number of carbons contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and R 10 to R 14 or R 20 to R 24 The total number of carbon atoms contained in at least one of the groups is 6 or more. n and p each independently represent 1 or 2, and s and u each independently represent an integer of 0 to 4. However, n+p is 2 or 3. When n is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenylene groups may be the same or different, and when p is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenyl groups may be the same or different. When s is an integer of 2 to 4, the multiple R 4 s may be the same or different, and when u is an integer of 2 to 4, the multiple R 3 s may be the same or different. R 1 and R 2 may be bonded to each other to form a ring, and adjacent groups of R 4 , R 10 to R 14 , and R 20 to R 24 may be bonded to each other to form a ring.)

8. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a hole injection layer and a light-emitting layer between an anode and a cathode, the hole injection layer is provided in contact with the anode, the hole injection layer contains a first organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm, The first organic compound is an organic compound represented by the following general formula (G3): the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 6】 (In the above general formula (G3), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms, and R 4 represents hydrogen or an alkyl group having 1 to 3 carbon atoms. R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbons form bonds only through sp3 hybrid orbitals. However, the total number of carbons contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and R 10 to R 14 or R 20 to R 24 The total number of carbon atoms contained in at least one of the groups is 6 or more. n and p each independently represent 1 or 2, and s and u each independently represent an integer of 0 to 4. However, n+p is 2 or 3. When n is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenylene groups may be the same or different, and when p is 2, the type of substituents, the number of substituents, and the position of the bond of the two phenyl groups may be the same or different. When s is an integer of 2 to 4, the multiple R 4 s may be the same or different, and when u is an integer of 2 to 4, the multiple R 3 s may be the same or different. R 1 and R 2 may be bonded to each other to form a ring, and adjacent groups of R 4 , R 10 to R 14 , and R 20 to R 24 may be bonded to each other to form a ring.)

9. In any one of claims 5 to 8, A light-emitting device, wherein s is 0.

10. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a light-emitting layer between an anode and a cathode, a layer containing a first organic compound having a refractive index of 1.75 or less for light having a wavelength of 467 nm between the anode and the light-emitting layer; The first organic compound is an organic compound represented by the following general formula (G4), the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 7】 (In the above general formula (G4), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms. R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbon forms bonds only through sp3 hybrid orbitals. The total number of carbon atoms contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and the total number of carbon atoms contained in at least one of R 10 to R 14 or R 20 to R 24 is 6 or more. u represents an integer of 0 to 4. Note that when u is an integer of 2 to 4, the multiple R 3 s may be the same or different from each other. In addition, R 1 and R 2 may be bonded to each other to form a ring, and R 10 to R 14 or R 20 to R 24 may be bonded to each other to form a ring. Adjacent groups may be bonded to each other to form a ring.

11. A light emitting device having a first light emitting device and a first color conversion layer, The first light-emitting device has a hole injection layer and a light-emitting layer between an anode and a cathode, the hole injection layer is provided in contact with the anode, the hole injection layer contains a first organic compound having a refractive index of 1.75 or less for light with a wavelength of 467 nm, The first organic compound is an organic compound represented by the following general formula (G4), the first color conversion layer includes a first substance that absorbs light and emits light; A light emitting device in which light emitted from the first light emitting device is irradiated onto the first color conversion layer. 【Chemistry 8】 (In the above general formula (G4), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms. R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbon forms bonds only through sp3 hybrid orbitals. The total number of carbon atoms contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and the total number of carbon atoms contained in at least one of R 10 to R 14 or R 20 to R 24 is 6 or more. u represents an integer of 0 to 4. Note that when u is an integer of 2 to 4, the multiple R 3 s may be the same or different from each other. In addition, R 1 and R 2 may be bonded to each other to form a ring, and R 10 to R 14 or R 20 to R 24 may be bonded to each other to form a ring. Adjacent groups may be bonded to each other to form a ring.)

12. In any one of claims 5 to 11, A light emitting device, wherein u is 0.

13. In any one of claims 5 to 12, The light-emitting device, wherein R 10 to R 14 and R 20 to R 24 are each independently any one of hydrogen, a tert-butyl group, and a cyclohexyl group.

14. In any one of claims 5 to 12, A light-emitting device, wherein at least three of R 10 to R 14 are hydrogen, and at least three of R 20 to R 24 are hydrogen.

15. In any one of claims 3 to 12, The hydrocarbon group having 1 to 12 carbon atoms in which the carbon forms bonds only through sp3 hybrid orbitals is an alkyl group having 3 to 8 carbon atoms or a cycloalkyl group having 6 to 12 carbon atoms.

16. In any one of claims 1 to 15, A light emitting apparatus, wherein the peak wavelength of the emission spectrum obtained from the first light emitting device is in the range of 440 nm to 520 nm.

17. In any one of claims 1 to 16, The light emitting device, wherein the first material is a quantum dot.

18. In any one of claims 1 to 17, The light emitting apparatus, wherein the first light emitting device comprises a microresonant structure.

19. In any one of claims 1 to 18, The first light emitting device comprises a plurality of light emitting layers.

20. 20. In claim 19, The light-emitting device further comprises a charge generating layer between the plurality of light-emitting layers.

21. In any one of claims 1 to 20, The light emitting device, wherein the first light emitting device emits blue light.

22. In any one of claims 1 to 21, The light emitting device has a color filter, The light emitting device, wherein the first color conversion layer is located between the first light emitting device and the color filter.

23. A light emitting device according to any one of claims 1 to 21, a sensor, an operation button, a speaker, or a microphone; An electronic device having the

24. A light emitting device comprising: the light emitting device according to claim 1 ; and a transistor or a substrate.

25. A lighting device comprising: the light-emitting device according to claim 1 ; and a housing.

Images