JPH08143862A - Light-emitting element - Google Patents

Abstract

PURPOSE: To obtain a light-emitting element having high utilization efficiency of electrical energy and an improved durability, capable of exhibiting high brightness and suitable as a display element by compounding a ketone compound having a carbazolyl group. CONSTITUTION: This light-emitting element has a light-emitting substance between a positive pole and a negative pole, and emits light by an electrical energy. In this invention, the light-emitting element contains a ketone compound having a carbazolyl group, preferably a compound of the formula (at least one of A is carbazolyl and the others are each H, an alkyl, an aryl or a cycloalkyl; (n) is 1 or 2; R is H, an alkyl, an aralkyl, a carbamoyl, an acyl, an alkoxycarbonyl, an aryl or a cycloalkyl; one of the R' combines to the ketone and the others combine each to H, an alkyl, an amino, a halogen, nitro, an acyl, hydroxyl or an alkoxy).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device capable of converting electric energy into light, such as a display device, a flat panel display, a backlight, an illumination, an interior, a sign,
The present invention relates to a light emitting element that can be suitably used in the fields of signboards, electrophotographic machines, and the like.

[0002]

2. Description of the Related Art As for elements for converting electric energy into light, many technologies have been studied and put to practical use since ancient times, and have become an indispensable technology in our lives. Typical light emitting elements include incandescent lamps, halogen lamps, fluorescent lamps, and light emitting diodes (L
ED), electroluminescence (EL), and the like, and are applied to many fields such as lighting, interiors, and display devices. In recent years, a flat panel display (FPD) has been attracting attention as a thin display replacing a cathode ray tube (CRT), many technologies have been studied, and some liquid crystal displays and the like are already at a practical level. In the FPD field, it is important that the device is thin and lightweight while maintaining high display quality.

To meet this requirement, the inorganic semiconductor materials such as ZnS, CaS, and SrS, which are the emission centers of M, are used.
Inorganic EL devices doped with rare earth elements such as n, Eu, Ce, Tb, and Sm are generally known. This element is a self-luminous element, which has the excellent characteristics that it does not need to be illuminated with light from the back like a liquid crystal display and has no dependence on the viewing angle, but it requires AC driving and a driving voltage of 100V. It has been pointed out that the brightness is low despite its high degree, and the life is short due to deterioration of the element due to humidity. In addition, the inability to emit blue light with high brightness makes it difficult to develop as a color display.

On the other hand, in recent years, active research has been conducted on organic laminated thin-film light emitting devices, in which electrons injected from a cathode and holes injected from an anode emit light when recombined in an organic phosphor sandwiched between both electrodes. I'm starting to be seen. This element is
It is thin and has high brightness light emission under low drive voltage and multicolor light emission by selecting fluorescent material. This study was conducted by Kodak Corporation. W. Since Tang et al. Have shown that organic thin film devices emit light with high brightness (App
l. Phys. Lett. 51 (12) 21, p. 91
3, 1987), many research institutes are investigating.
A typical structure of an organic laminated thin film light emitting device presented by a research group of Kodak Company is a diamine compound having a hole transporting property on an ITO glass substrate, 8-hydroxyquinoline aluminum as a light emitting layer, and Mg: Ag as a cathode. It is provided in sequence, 1000c at a driving voltage of about 10V
A green light emission of d / m2 was possible. In the current organic laminated thin film light emitting device, in addition to the above-mentioned device constituent elements, there are those in which the structure is changed such as an electron transport layer provided,
Basically, it follows the structure of Kodak. However, the device characteristics largely depend on the material, and various substances are being studied for that reason.

The organic laminated thin film light emitting device material is described in "Organic EL Device Development Strategy" edited by the Next Generation Display Device Study Group (Science Forum, 1992). According to this, a phosphor is used as the material of the light emitting layer. The holes injected from the hole transport layer and the electrons injected from the cathode are recombined in the light emitting layer, and at this time, the phosphor is excited to emit light. Therefore, the light emitting layer material is required to have carrier transporting ability in addition to fluorescence. For example, it is known that 8-hydroxyquinoline aluminum used in the device of Tang et al. Mentioned above has an electron transporting property. Generally, when the light emitting layer has an electron transporting property,
It is effective to provide a hole transport layer between the transparent electrode (positive electrode) and the light emitting layer, and an electron transport layer between the back electrode (negative electrode) and the light emitting layer when the light emitting layer has a hole transporting property. It is said that it is effective to sandwich the light emitting layer between the hole transporting layer and the electron transporting layer when a material that transports both carriers of electrons and holes equally is used. It is considered that the higher the quantum efficiency of the phosphor, the higher the intensity of light emission that can be obtained, but in reality, concentration quenching occurs and it is difficult to use itself as a light emitting material. However, Tang et al. Improve the luminous efficiency of the device by causing energy transfer from the host molecule to dope by minutely doping a dye with high fluorescence quantum efficiency such as coumarin into the 8-hydroxyquinoline aluminum luminous layer. It has been confirmed that the emission wavelength can be shifted to enable multicolor emission (J. Appl. Phy
s. 65 (9) p. 3610, 1989). In addition, it has been pointed out that good film-forming properties such as vapor deposition and thermal and chemical stability during light emission are required. A π-conjugated compound is often used as a light emitting layer material satisfying such requirements. Specifically, in addition to anthracene and pyrene, which have been known as light emitters for a long time, and the aforementioned 8-hydroxyquinoline aluminum, for example, bisstyrylanthracene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives , Distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, thiadiazolopyridine derivatives, and polymer systems such as polyphenylene vinylene derivatives, polyparaphenylene derivatives, and polythiophene derivatives are known, and they emit a large amount of light. Colorization is possible. Further, as the dopant added to the light emitting layer, rubrene, a quinacridone derivative,
Phenoxazone 660, DCM1, perinone, perylene, coumarin 540, and the like are known, and it is possible to improve luminous efficiency and achieve multicolor emission.

The electrodes also have a large role in determining the device characteristics. Since this element is a light emitting element, there is a restriction that either the cathode or the anode must be transparent. In most cases, a transparent material is used for the anode.
TO, Nesa glass and the like are typical, but thinly-deposited gold and the like are also used, and any electrode that does not significantly impair light transmission can be used. However, the surface condition of the anode is required to be very clean, and it has been pointed out that, for example, cleaning the ITO glass substrate greatly affects the device characteristics. The cathode is often deposited with an opaque material such as magnesium or silver. Other than the above, as the cathode material, aluminum, gold, indium, etc. are also known, but a low work function metal is used to facilitate injection of electrons, and in that sense, an alkali metal or the like is effective. As expected, magnesium or its alloys are still widely used in consideration of the stability of metals.

With respect to the carrier transport material, a high carrier transport ability is required to improve the light emission efficiency against electric power, and an appropriate electron level material should be selected for confining excitons in the light emitting layer and improving the carrier injection efficiency. It is valid. Further, it has been shown that it is also important not to form an exciplex at the interface with the light emitting layer in order to efficiently convert electric energy into light. Film thickness and film forming ability are also important requirements in actual device fabrication. The carrier transport material includes an electron transport material and a hole transport material. Specific examples of the electron transport material include oxadiazole derivatives and 8
-Hydroxyquinoline aluminum, etc. are known, but there is not much knowledge and there is room for consideration, and if the blocking of holes and the injection efficiency of electrons can be improved by selecting the material, it will be extremely high. It is possible to create high performance devices. On the other hand, as the hole transport material, hydrazone compounds, stilbene compounds, triphenylamine compounds, and heterocyclic compounds represented by oxadiazole derivatives and phthalocyanine derivatives are specifically shown. However, there are still many problems that it has such as insufficient heat resistance and disorder of the interface due to crystallization. Further, studies have also been conducted on polymer systems, and polycarbonates, styrene derivatives, polyvinylcarbazole, polysilane, etc. having the above-mentioned monomer in the side chain have been shown. The high molecular weight polymer is superior to other monomer-based hole transporting materials in terms of device durability. Among them, polyvinylcarbazole is easily formed into a thin film by solution coating and further contains a carbazolyl skeleton. It has excellent properties compared to high molecular weight compounds. However, the carrier mobility of polyvinylcarbazole shows a low value as compared with other monomer-based hole transport materials because traps are generated due to its structure.

[0008]

As described above, the organic laminated thin film light emitting device of the prior art has low luminous efficiency and low durability, and thus has a high carrier transporting ability.
A material having a good film-forming property and having thermal and chemical stability during light emission is desired.

The present invention solves such a problem and provides a low voltage,
It is an object of the present invention to provide a highly durable element capable of emitting high brightness light even under a low current.

[0010]

Means for Solving the Problems The present invention is to achieve the above-mentioned object. “In a device which emits light by electric energy, there is a substance controlling light emission between the positive electrode and the negative electrode, and the device is carbazolyl. A light-emitting device comprising a ketone compound having a group. "

In the present invention, the positive electrode is a conductive metal oxide such as tin oxide, indium oxide or indium tin oxide (ITO), or gold, if it is transparent for extracting light.
Metals such as silver and chromium, inorganic conductive materials such as copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline are not particularly limited, but ITO glass or Nesa glass is particularly preferable. The resistance of the transparent electrode is not limited as long as it can supply a sufficient current for light emission of the device, but is preferably low resistance from the viewpoint of power consumption of the device. For example, 300Ω
Although an ITO substrate under / m ² functions as an element electrode, it is now possible to supply a substrate of about 10 Ω / m ^2, so it is particularly desirable to use a low resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but it is usually used in the range of 1000 to 3000 angstroms. Further, soda lime glass, non-alkali glass or the like is used as the glass substrate, and the thickness is preferably 0.7 mm or more because it is sufficient if the thickness is sufficient to maintain mechanical strength. Regarding the material of the glass, non-alkali glass is preferable because it is preferable that the amount of ions eluted from the glass is small, but soda lime glass coated with a barrier coat such as SiO ₂ is also commercially available and can be used. The ITO film forming method is not particularly limited, such as an electron beam method, a sputtering method and a chemical reaction method.

Since the negative electrode must supply electrons efficiently to a substance that controls light emission or a substance adjacent to the substance that controls light emission (for example, an electron transport layer), the adhesion between the electrode and the adjacent substance and energy level. Will need to be adjusted. In addition, it is particularly desirable to use a material that is relatively stable in the air in order to maintain stable performance for long-term use, but it is also possible to use a protective film, so it is not limited to this. It is not something that will be done. Specifically, it is possible to use metals such as indium, gold, silver, aluminum, lead, magnesium, lanthanum, europium, and ytterbium, simple earths of rare earths, alkali metals, or alloys thereof. Considering the device characteristics, it is desirable to use magnesium or its alloy (for example, with silver). The electrodes are manufactured by a resistance heating method, an electron beam method, a sputtering method,
A coating method or the like is used, and the metal can be vapor-deposited alone or two or more components can be vapor-deposited simultaneously. Particularly, for forming an alloy, it is possible to easily form an alloy electrode by simultaneously vapor-depositing a plurality of metals.

The substances that control light emission are 1) hole transport layer / light emitting layer, 2) hole transport layer / light emitting layer / electron transport layer, 3) light emitting layer / electron transport layer, and 4) a combination of the above. It may be in a form in which the substances are mixed in one layer. That is, as the element structure, in addition to the multilayer laminated structure of 1) to 3) above, 4)
As described above, the light emitting material alone or only one layer containing the light emitting material and the hole transporting material and / or the electron transporting material may be provided. However, it is necessary that these substances that control light emission include a ketone compound having a carbazolyl group. Is. Among them, since a ketone compound having a carbazolyl group has a hole transporting ability by nature, it is preferably used as a hole transporting substance, but not limited to this.

The ketone compound having a carbazolyl group in the present invention has a high carrier transporting ability by binding a carbazolyl group having a hole transporting ability with a carbazolyl group via a carbonyl bond capable of conjugating and stabilizing, In addition, the film forming property was good, and it was possible to have both thermal and chemical stability during light emission. Since the carbazolyl group has high reactivity at the 3-position, it is particularly preferable to use a (3-carbazolyl) ketone compound. Further, since the hole-transporting ability depends on the carbazolyl group, it is advantageous that the proportion of the carbazolyl group in the molecular weight is high. It is preferable to use a (3-carbazolyl) monoketone compound, and the carbazolyl group having the hole-transporting ability is used. It is more preferable to use a bis (3-carbazolyl) monoketone compound having two

When this compound is used alone as a hole transport material, it can be used alone, but N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diamine, etc. Triphenylamines, tertiary amines such as N-isopropylcarbazole, pyrazoline derivatives,
In stilbene compounds, hydrazone compounds, heterocyclic compounds represented by oxadiazole derivatives and phthalocyanine derivatives, in polymer systems, it may be used in combination with a polycarbonate or styrene derivative having the above monomer in the side chain, polyvinylcarbazole, polysilane, etc. It is also possible to use them alone or in a dispersion together with the above compounds in the molecular binder.

As the ketone compound having a carbazolyl group of the present invention, for example, a compound represented by the following general formula is preferably used.

[0017]

[Chemical 6] (However, in the above formula, at least one of A's represents a carbazolyl group and the rest represents at least one substituent selected from hydrogen, an alkyl group, an aryl group, and a cycloalkyl group. N is 1 or 2 In the carbazolyl group A, R represents at least one substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. One of R's contained in the carbazolyl group represents a bond with a ketone, and other than that, at least one selected from hydrogen, an alkyl group, an amino group, a halogen, a nitro group, an acyl group, a hydroxyl group and an alkoxy group. And represents a substituent of a 3-carbazolyl ketone compound represented by the following general formula: It is preferred that

[0018]

[Chemical 7] (In the above formula, n represents an integer of 1 or 2, and R represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. Represents a substituent selected from a group, an aryl group and a cycloalkyl group.) Further, a 3-carbazolyl monoketone compound represented by the following general formula is also preferably used.

[0019]

Embedded image (In the above formula, R represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group. One of the groups represents a bond with a ketone, and the other groups represent at least one kind of substituent selected from hydrogen, an alkyl group, an amino group, a halogen, a nitro group, an acyl group, a hydroxyl group and an alkoxy group. R "represents at least one substituent selected from hydrogen, an alkyl group, an aryl group and a cycloalkyl group.) Further, a bis (3-carbazolyl) ketone compound represented by the following general formula is also preferably used.

[0020]

[Chemical 9] (However, in the above formula, n represents an integer of 1 or 2, R may be the same or different, and hydrogen,
It represents a substituent selected from an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. ) Furthermore, bis (3-carbazolyl) represented by the following general formula
Monoketone compounds are also preferably used.

[0021]

[Chemical 10] (In the above formula, R may be the same or different and each represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. , R ′ contained in each carbazolyl group
Represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. ) Hereinafter, typical structural formulas of the ketone compound having a carbazolyl group used in the above light emitting device of the present invention will be shown, but the present invention is not limited thereto.

[Chemical 11]

[Chemical 12]

[Chemical 13]

Embedded image

[Chemical 15]

Embedded image

[Chemical 17]

Embedded image Further, as a method for producing a ketone compound having a carbazolyl group, Friedel-Crafts reaction or acylation from carbazole or a carbazole derivative, Vil
It can be synthesized by the Smeier reaction or the like. Also,
Biscarbazolyl ketone and biscarbazolyl diketone can be synthesized by reacting carbazole or a carbazole derivative with oxalyl chloride in the presence of a Lewis acid, but not limited thereto. Aluminum chloride, titanium chloride, tin chloride or the like can be used as the Lewis acid.

The ketone compound having a carbazolyl group can be formed into a film by spin coating, casting, the LB method, resistance heating vapor deposition or the like and used as a hole transporting material, a light emitting material or an electron transporting material. Further, they can be mixed and used as a hole transport material, a light emitting material, and an electron transport material.

The material for the light emitting layer is not particularly limited, but in addition to anthracene and pyrene, which have been known as light emitters for a long time, and the above-mentioned 8-hydroxyquinoline aluminum, for example, a bisstyrylanthracene derivative. , Tetraphenylbutadiene derivative, coumarin derivative, oxadiazole derivative, distyrylbenzene derivative, pyrrolopyridine derivative, perinone derivative, cyclopentadiene derivative, oxadiazole derivative, thiadiazolopyridine derivative, in polymer system, polyphenylene vinylene derivative, poly Paraphenylene derivatives and polythiophene derivatives can be used. The dopant added to the light emitting layer includes rubrene, a quinacridone derivative, phenoxazone 660, DCM1, and
Perinone, perylene, coumarin 540, etc. can be used as they are.

As the electron-transporting substance, it is necessary to efficiently transport the electrons from the cathode between the electrodes to which an electric field is applied, and the electron injection efficiency is high, and it is desirable to efficiently transport the injected electrons. . For that purpose, it is required that the substance has a high electron affinity, a high electron mobility, an excellent stability, and an impurity that becomes a trap is hard to be generated during production and use. As substances satisfying such conditions, oxadiazole derivatives and 8
-Hydroxyquinoline aluminum and the like are not particularly limited.

The above materials used for the hole transporting layer, the light emitting layer and the electron transporting layer can be used to form each layer independently, but as the polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N- Vinylcarbazole), polymethylmethacrylate, polybutylmethacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide,
Solvent-soluble resins such as ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, phenol resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin,
It is also possible to use it by dispersing it in a curable resin such as a silicone resin.

The method of forming the substance that controls the light emission is not particularly limited, such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method and coating method, but normally resistance heating vapor deposition and electron beam vapor deposition are the characteristics. It is preferable from the aspect. The thickness of the layer cannot be limited because it depends on the resistance value of the substance that controls light emission, but empirically it is 100 to 100.
Choose from between 00 Angstroms. For example, polyvinylcarbazole is used for the hole transport layer and 8-
When hydroxyquinoline aluminum is used, the thickness of each layer is such that the thickness of polyvinylcarbazole is 100 to 7
00 angstrom is preferable, and 200 to 500 angstrom is more preferable. The film thickness of 8-hydroxyquinoline aluminum is preferably 200 to 2000 angstroms, more preferably 500 to 1200 angstroms.

The electric energy in the present invention mainly refers to a direct current, but it is also possible to use a pulse current or an alternating current. The current value and voltage value are not particularly limited,
Considering the power consumption and life of the device, maximum brightness should be obtained with the lowest possible energy.

[0028]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A glass substrate (15 Ω / m ² ) having 1500 Å of ITO transparent conductive film deposited thereon was cut into a predetermined size,
After etching, cleaning was performed. This was placed in a vacuum vapor deposition apparatus and evacuated until the degree of vacuum inside the apparatus became 5 × 10 ⁻⁶ Torr or less. First, the following compound (A-1) is added to 50
0 angstrom was vapor-deposited, and 8-hydroxyquinoline aluminum was vapor-deposited to a thickness of 1000 angstrom. Next, magnesium of 500 angstrom and silver of 1500 angstrom were vapor-deposited to prepare a 5 × 5 mm square element. The maximum brightness of this light emitting device is 4000 cd
/ M ² (20.4 V, 130 mA).

[0030]

[Chemical 19] Example 2 The maximum brightness of the device obtained in exactly the same manner as in Example 1 except that the following compound (A-2) was used instead of the compound (A-1) was 3500 cd / m ² (19.6 V, 1
It was 20 mA).

[0031]

[Chemical 20] Comparative Example 1 The maximum luminance of the device obtained in exactly the same manner as in Example 1 except that the triphenyldiamine compound (TPD) was used instead of the compound (A-1) was 1450 cd / m ^2.
It was (12.1V, 60mA).

Example 3 A glass substrate (15 Ω / m ² ) having 1500 Å of ITO transparent conductive film deposited thereon was cut into a predetermined size,
After etching, cleaning was performed. The substrate was set on a spin coater, and 50 parts by weight of the compound (A-1) was dispersed in 50 parts by weight of polymethyl methacrylate using dichloroethane, and spin-coated at a rotation speed of 5000 rpm to a thickness of 500 angstroms. . This is installed in the vacuum evaporation system, and the vacuum degree in the system is 5 × 10.
^-6 Torr was evacuated to below. Aluminum 8-hydroxyquinoline was deposited to a thickness of 1000 Å. Next, magnesium (500 Å) and silver (1500 Å) are vapor-deposited to form 5 × 5 mm.
A corner element was made. The maximum brightness of this light emitting device is 62
It was 70 cd / m ² (24.6 V, 170 mA).

Example 4 The maximum luminance of the device obtained in exactly the same manner as in Example 3 except that the following compound (A-3) was used in place of the compound (A-1) was 7400 cd / m ² (26 .4V, 1
It was 40 mA).

[0034]

[Chemical 21] Comparative Example 2 The maximum luminance of the device obtained in exactly the same manner as in Example 3 except that polyvinylcarbazole was used instead of the compound (A-1) was 4800 cd / m ² (24.3 V,
180 mA).

[0035]

INDUSTRIAL APPLICABILITY The present invention can provide a high-brightness light emitting device with high utilization efficiency of electric energy and improved durability.

Claims (9)

[Claims] 1. A light emitting device, in which a substance that controls light emission exists between a positive electrode and a negative electrode, and the device includes a ketone compound having a carbazolyl group in the device which emits light by electric energy. 2. The light emitting device according to claim 1, wherein the ketone compound having a carbazolyl group is a compound represented by the following general formula. Embedded image (However, in the above formula, at least one of A's represents a carbazolyl group and the rest represents at least one substituent selected from hydrogen, an alkyl group, an aryl group, and a cycloalkyl group. N is 1 or 2 In the carbazolyl group A, R represents at least one substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. One of R's contained in the carbazolyl group represents a bond with a ketone, and other than that, at least one selected from hydrogen, an alkyl group, an amino group, a halogen, a nitro group, an acyl group, a hydroxyl group and an alkoxy group. Represents a substituent of.) 3. The light emitting device according to claim 1, wherein the ketone compound having a carbazolyl group is a 3-carbazolyl ketone compound represented by the following general formula. Embedded image (In the above formula, n represents an integer of 1 or 2, and R represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. Represents a substituent selected from a group, an aryl group and a cycloalkyl group.) 4. The light emitting device according to claim 1, wherein the ketone compound having a carbazolyl group is a 3-carbazolyl monoketone compound represented by the following general formula. Embedded image (In the above formula, R represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group. One of the groups represents a bond with a ketone, and the other groups represent at least one kind of substituent selected from hydrogen, an alkyl group, an amino group, a halogen, a nitro group, an acyl group, a hydroxyl group and an alkoxy group. R "represents at least one substituent selected from hydrogen, an alkyl group, an aryl group and a cycloalkyl group.) 5. The light emitting device according to claim 1, wherein the ketone compound having a carbazolyl group is a bis (3-carbazolyl) ketone compound represented by the following general formula. [Chemical 4] (However, in the above formula, n represents an integer of 1 or 2, R may be the same or different, and hydrogen,
It represents a substituent selected from an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. Further, R ′ contained in the carbazolyl group represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. ) 6. The light emitting device according to claim 1, wherein the ketone compound having a carbazolyl group is a bis (3-carbazolyl) monoketone compound represented by the following general formula. Embedded image (In the above formula, R may be the same or different and each represents a substituent selected from hydrogen, an alkyl group, an aralkyl group, a carbamoyl group, an acyl group, an alkoxycarbonyl group, an aryl group and a cycloalkyl group. , R ′ contained in each carbazolyl group
Represents at least one kind of substituent selected from hydrogen, alkyl group, amino group, halogen, nitro group, acyl group, hydroxyl group and alkoxy group. ) 7. The substance controlling light emission comprises a hole transport layer and a light emitting layer.
The light-emitting element according to the item. 8. The substance controlling light emission comprises a hole transporting layer, an electron transporting layer and a light emitting layer.
The light emitting device according to any one of 1. 9. A display device using the light emitting device according to claim 1.