JP2001332385A - Light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element which has high luminous efficiency, high luminance, and which is superior in chromatic purity. SOLUTION: This is an element in which a luminescent substance exists between a positive electrode and a negative electrode, and which emits light by the electric energy, and the element is the light emitting element containing an organic fluorescent material having a fluorescent skeleton substituted by silyl group(s), and the organic fluorescent material having the fluorescent skeleton substituted by silyl group(s) is a compound of a formula (1). Here, R1 to R4 are respectively hydrogen, alkyl group, cycloalkyl group, aralkyl group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, mercapto group, alkoxy group, alkylthio group, aryl ether group, arylthio ether group, aryl group, heterocyclic group, halogen, haloalkane, haloalkene, haloalkyne, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group, nitro group, or siloxanyl group, and further, at least one of R1 to R4 has the fluorescent skeleton.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element capable of converting electric energy into light, and relates to a display element, a flat panel display, a backlight, lighting, an interior, a sign, a sign, an electrophotographic device, an optical signal generator, and the like. The present invention relates to a light emitting element that can be used in the field of (1).

[0002]

2. Description of the Related Art In recent years, studies have been actively 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 they recombine in an organic phosphor sandwiched between both electrodes. ing. This device has attracted attention because it is thin, emits light with high luminance under a low driving voltage, and emits multicolor light by selecting a fluorescent material.

[0003] This study was carried out by Kodak Corporation. W. Tan
g. et al. showed that the organic laminated thin film element emits light with high luminance (Appl. Phys. Lett. 51 (12)
21, p. 913, 1987), and many research institutions are conducting studies. A typical configuration 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 and a light emitting layer on an ITO glass substrate.
Aluminum hydroxyquinoline and M as cathode
g: Ag was sequentially provided, and green light emission of 1000 cd / m ² was possible at a driving voltage of about 10 V. The present organic laminated thin-film light-emitting device has a different configuration, such as a device provided with an electron transport layer in addition to the above-described device components, but basically follows the configuration of Kodak Company.

[0004] The light emitting layer is composed of only a host material,
A host material is doped with a guest material.
The light emitting material is required to have three primary colors, but the research on the green light emitting material has been most advanced so far. At present, intensive studies have been made on red light emitting materials and blue light emitting materials with the aim of improving the characteristics. In particular, a blue light-emitting material that can emit light with high luminance and good color purity is desired.

As the host material, the above-mentioned tris (8-
Metal complexes of quinolinol derivatives including quinolinolato) aluminum, benzoxazole derivatives, stilbene derivatives, benzothiazole derivatives, thiadiazole derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, oxadiazole derivatives, oxadiazole derivative metal complexes And benzazole derivative metal complexes.

As an example of a blue light-emitting host material having relatively good performance, a metal complex obtained by combining a quinolinol derivative with a different ligand (Japanese Patent Laid-Open No. 5-21)
No. 4332) and bisstyrylbenzene derivatives (JP-A-4-117485), but the color purity is not particularly sufficient.

On the other hand, as a dopant material as a guest material, coumarin derivatives such as 7-dimethylamino-4-methylcoumarin, perylene, pyrene and anthracene, which are known to be useful as laser dyes, are known. Fused aromatic ring derivatives, stilbene derivatives, oligophenylene derivatives, furan derivatives, quinolone derivatives, oxazole derivatives, oxadiazole derivatives and the like are known.

[0008]

However, many light-emitting materials (host materials and dopant materials) used in the prior art have low light-emitting efficiency and high power consumption, and have low durability and short element life. Was. In addition, red, green, and blue light emission of three primary colors is required as a full-color display. However, in red and blue light emission, few light emission wavelengths are satisfied, and few light emission peaks have a wide emission peak width and good color purity. In particular, for blue light emission, a material having excellent durability and sufficient luminance and color purity characteristics is required.

An object of the present invention is to solve the problems of the prior art and to provide a light emitting device having high luminous efficiency, high luminance and excellent color purity.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to an element which emits light by electric energy in which a light emitting substance is present between a positive electrode and a negative electrode, wherein the element has an organic skeleton having a fluorescent skeleton substituted with a silyl group. A light-emitting element including a phosphor.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a positive electrode is made of a conductive metal oxide such as tin oxide, indium oxide, indium tin oxide (ITO) or a metal such as gold, silver or chromium if it is transparent to extract light. Although not particularly limited, such as metals, inorganic conductive substances such as copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline, it is particularly preferable to use ITO glass or Nesa glass. The resistance of the transparent electrode is not limited as long as a current sufficient for light emission of the element can be supplied, but is preferably low from the viewpoint of power consumption of the element. For example, 3
Although an ITO substrate having a resistance of 00 Ω / □ or less functions as an element electrode, a substrate having a resistance of about 10 Ω / □ can be supplied at present. The thickness of the ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of usually 100 to 300 nm. Further, the glass substrate is made of soda lime glass, non-alkali glass, or the like, and the thickness only needs to be sufficient to maintain the mechanical strength.
mm or more is sufficient. For the glass material,
Alkali-free glass is preferred because less ions elute from the glass is preferred, but soda-lime glass with a barrier coat such as SiO ₂ is also commercially available and can be used. The method of forming the ITO film is not particularly limited, such as an electron beam method, a sputtering method, and a chemical reaction method.

In the present invention, the cathode is not particularly limited as long as it can efficiently inject electrons into the organic material layer.
Generally, platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium, magnesium and the like,
Lithium, sodium, potassium, calcium, magnesium, or an alloy containing these low work function metals is effective in improving the element characteristics by increasing the electron injection efficiency. However, these low work function metals are generally unstable in the air in many cases. For example, a very small amount of lithium or magnesium (1 nm in a vacuum-evaporated film thickness gauge) is added to an organic layer.
Preferred examples include a method of doping the following) and using an electrode having high stability, but the method is not particularly limited since inorganic salts such as lithium fluoride can be used. . Furthermore, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals, and inorganic substances such as silica, titania and silicon nitride, polyvinyl alcohol, vinyl chloride, It is preferable to laminate a hydrocarbon polymer or the like. The method for producing these electrodes is not particularly limited, as long as electrical conduction such as resistance heating, electron beam, sputtering, ion plating, and coating can be achieved.

In the present invention, the luminescent substance includes 1) a hole transport layer / a light emitting layer, 2) a hole transport layer / a light emitting layer / an electron transport layer, 3) a light emitting layer / an electron transport layer, and 4) a hole transport layer. / Light emitting layer / hole blocking layer, 5) hole transporting layer / light emitting layer / hole blocking layer /
An electron transport layer, 6) a light emitting layer / a hole blocking layer / an electron transport layer, and 7) a combination of any of the above substances may be used. That is, as the element configuration, in addition to the multilayer laminated structure of the above 1) to 6), only a layer containing a luminescent material alone or a layer containing a luminescent material and a hole transporting material or an electron transporting material as in 7) may be provided. Further, the luminescent substance in the present invention corresponds to both a substance which emits light by itself and a substance which assists the light emission, and refers to a compound, a layer, or the like involved in light emission.

In the present invention, the hole transporting layer is formed of a hole transporting substance alone or a mixture of two or more kinds of substances or a mixture of a hole transporting substance and a polymer binder.
As a hole transporting substance, it is necessary to efficiently transport holes from the positive electrode between electrodes to which an electric field is applied, and it is desirable to have a high hole injection efficiency and to efficiently transport injected holes. . For that purpose, it is required that the ionization potential be small, the hole mobility be large, the stability be further improved, and impurities serving as traps be hardly generated during production and use. The substance satisfying such conditions is not particularly limited,
N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine;
N, N'-dinaphthyl-N, N'-diphenyl-4,
Triphenylamines such as 4'-diphenyl-1,1'-diamine, bis (N-allylcarbazole) or bis (N-alkylcarbazole), pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives And a phthalocyanine derivative, a heterocyclic compound represented by a porphyrin derivative, in a polymer system, a polycarbonate or a styrene derivative having the monomer in a side chain, polyvinyl carbazole, polysilane and the like are preferable, but a thin film necessary for element production is formed. The compound is not particularly limited as long as it is a compound capable of injecting holes from the positive electrode and further transporting holes.

In the present invention, the light emitting material may be a host material alone or a combination of a host material and a dopant material.
Any of them may be used. In addition, the dopant material may be included in the entire host material, partially, or may be included. The dopant material may be stacked, dispersed, or the like.

[0016] Even if a phosphor is generally considered to have strong fluorescence, even if it is dispersed in a dilute solution, if the solution is thick or solid, the intermolecular interaction strongly acts. A phenomenon called concentration quenching, in which the fluorescence is weakened, is observed. In the organic laminated thin-film light-emitting device, the light-emitting properties have a close correlation with the fluorescent properties of the light-emitting material,
Among light-emitting materials, particularly in a host material, strong fluorescence is required in a solid state. Therefore, a device for reducing the intermolecular interaction between the fluorescent skeletons in the solid state is required.

In the present invention, it is preferable to use an organic phosphor having a fluorescent skeleton substituted with a silyl group in order to reduce the above-mentioned effects. Since the steric property can be controlled by the silyl group, the substituent to be introduced into the silyl group is not particularly limited. However, a steric substituent such as an isopropyl group or a tbutyl group, or a phenyl group can be used. And a substituent which becomes steric due to steric repulsion between adjacent substituents such as a thiol group, a naphthyl group and a fluorene group, or a fluorescent skeleton. It is also preferable that the fluorescent skeletons become three-dimensional due to steric repulsion.

Specific examples of the organic phosphor having a fluorescent skeleton substituted with a silyl group include a compound represented by the following general formula (1).

[0019]

Embedded image

Here, R ^{1 to} R ⁴ each represent hydrogen, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a mercapto group, an alkoxy group, an alkylthio group, an aryl ether group, Aryl thioether group, aryl group, heterocyclic group, halogen, haloalkane, haloalkene, haloalkyne, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group,
It is selected from a nitro group and a siloxanyl group. Also R ¹
At least one of to R ⁴ is a fluorescent skeleton.

If the ratio of the fluorescent skeleton portion in the organic fluorescent substance is too high, the steric effect of the silyl group will be reduced, so that the organic fluorescent substance having a fluorescent skeleton substituted with a silyl group is specifically represented by the following general formula ( Compounds represented by 2) and the following general formula (3) are more preferred.

[0022]

Embedded image

Where R^Five~ R⁷Are hydrogen and alk, respectively.
Group, cycloalkyl group, aralkyl group, alkenyl
Group, cycloalkenyl group, alkynyl group, hydroxyl group, mel
Capto group, alkoxy group, alkylthio group, aryl
-Tel group, arylthioether group, aryl group, hetero
Ring group, halogen, haloalkane, haloalkene, haloa
Lucin, cyano group, aldehyde group, carbonyl group, cal
Boxyl group, ester group, carbamoyl group, amino group,
It is selected from a nitro group and a siloxanyl group. X ¹Is a firefly
Represents a light skeleton.

[0024]

Embedded image

(Where R ^{8 to} R ¹⁰ are each hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, arylether, , Arylthioether group, aryl group, heterocyclic group, halogen, haloalkane, haloalkene, haloalkyne, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group, nitro group, siloxanyl group X ²
Represents a fluorescent skeleton. n represents a natural number of 2 or more. Of these substituents, an alkyl group is, for example, a methyl group,
It represents a saturated aliphatic hydrocarbon group such as an ethyl group, a propyl group and a butyl group, which may be unsubstituted or substituted. The cycloalkyl group is, for example, a saturated alicyclic hydrocarbon group such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl, which may be unsubstituted or substituted. The aralkyl group refers to an aromatic hydrocarbon group via an aliphatic hydrocarbon such as a benzyl group and a phenylethyl group, and the aliphatic hydrocarbon and the aromatic hydrocarbon may be unsubstituted or substituted. I don't care. The alkenyl group is, for example, a vinyl group,
It represents an unsaturated aliphatic hydrocarbon group containing a double bond such as an allyl group or a butadienyl group, which may be unsubstituted or substituted. The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, and a cyclohexene group, which may be unsubstituted or substituted. . The alkynyl group means an unsaturated aliphatic hydrocarbon group containing a triple bond such as an acetylenyl group, which may be unsubstituted or substituted. The alkoxy group refers to an aliphatic hydrocarbon group via an ether bond such as a methoxy group, and the aliphatic hydrocarbon group may be unsubstituted or substituted. The alkylthio group is obtained by substituting the oxygen atom of the ether bond of the alkoxy group with a sulfur atom. Further, the aryl ether group refers to an aromatic hydrocarbon group via an ether bond such as a phenoxy group, and the aromatic hydrocarbon group may be unsubstituted or substituted. Further, the arylthioether group is a group in which an oxygen atom of an ether bond of the arylether group is substituted with a sulfur atom. The aryl group refers to, for example, an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenyl group, a phenanthryl group, a terphenyl group, and a pyrenyl group, which may be unsubstituted or substituted. Further, the heterocyclic group refers to a cyclic structural group having an atom other than carbon, such as a furyl group, a thienyl group, an oxazolyl group, a pyridyl group, a quinolyl group, and a carbazolyl group, which may be unsubstituted or substituted. Absent. Halogen refers to fluorine, chlorine, bromine and iodine. Haloalkanes, haloalkenes, and haloalkynes are those in which part or all of the aforementioned alkyl group, alkenyl group, and alkynyl group such as a trifluoromethyl group have been substituted with the aforementioned halogen, and the remaining part is unsubstituted. It may be replaced. Aldehyde, carbonyl, ester, carbamoyl, and amino groups include those substituted with aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, heterocycles, and the like. The cyclic hydrocarbon, aromatic hydrocarbon and heterocyclic ring may be unsubstituted or substituted. The silyl group means a silicon compound group such as a trimethylsilyl group, which may be unsubstituted or substituted.
The siloxanyl group means a silicon compound group via an ether bond such as a trimethylsiloxanyl group, which may be unsubstituted or substituted. Further, a ring structure may be formed between adjacent substituents. The ring structure formed may be unsubstituted or substituted.

The fluorescent skeleton is not particularly limited as long as it has fluorescence. Specific examples include the basic skeleton of a compound used as a known host material or dopant material described later. In particular, the effect of the silyl group is more exerted on the fluorescent skeleton having a planar structure. Further, a fluorescent skeleton having a planar structure is advantageous because many of them have strong fluorescence. Specific examples include a condensed aromatic ring, and among them, a condensed aromatic ring having four or more ring structures is preferable.

Specific examples of the organic phosphor having a fluorescent skeleton substituted by the silyl group include the following structures.

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

An organic phosphor having a fluorescent skeleton substituted with a silyl group may be used as a dopant material, but is preferably used as a host material because of its excellent electron transport ability.

The host material of the light emitting material is not limited to one kind of organic phosphor having a fluorescent skeleton substituted with a silyl group, but may be a mixture of organic phosphors having a fluorescent skeleton substituted with a plurality of silyl groups. Or one or more known host materials may be mixed with an organic phosphor having a fluorescent skeleton substituted with a silyl group. Known host materials are not particularly limited, but anthracene, phenanthrene, which has long been known as a luminescent material,
Fused ring derivatives such as pyrene, perylene and chrysene, metal complexes of quinolinol derivatives including tris (8-quinolinolato) aluminum, benzoxazole derivatives, stilbene derivatives, benzthiazole derivatives, thiadiazole derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, Bisstyryl derivatives such as cyclopentadiene derivatives, oxadiazole derivatives, bisstyrylanthracene derivatives and distyrylbenzene derivatives,
Metal complexes combining quinolinol derivatives and different ligands, oxadiazole derivative metal complexes, benzazole derivative metal complexes, coumarin derivatives, pyrrolopyridine derivatives, perinone derivatives, thiadiazolopyridine derivatives,
In the polymer system, a polyphenylenevinylene derivative, a polyparaphenylene derivative, a polythiophene derivative, and the like can be used.

The dopant material to be added to the light emitting material is not particularly limited, but specific examples include phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, and rubrene. Condensed ring derivatives such as benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives , Tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyryl anthracene derivatives, bisstyryl derivatives such as distyrylbenzene derivatives, diaza Ndasen derivatives, furan derivatives,
Benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di (2-methylphenyl) isobenzofuran, di (2-trifluoromethylphenyl) isobenzofuran, isobenzofuran derivatives such as phenylisobenzofuran, dibenzofuran derivatives, 7
-Dialkylaminocoumarin derivative, 7-piperidinocoumarin derivative, 7-hydroxycoumarin derivative, 7-methoxycoumarin derivative, 7-acetoxycoumarin derivative, 3-benzthiazolyl coumarin derivative, 3-benzimidazolyl coumarin derivative, 3- Coumarin derivatives such as benzoxazolyl coumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives,
Polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, bis (styryl)
Benzene derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives,
Pyrrolopyridine derivatives, furopyridine derivatives, 1,2,2
A 5-thiadiazolopyrene derivative, a perinone derivative, a pyrrolopyrrole derivative, a squarylium derivative, a biolanthrone derivative, a phenazine derivative, an acridone derivative, a diazaflavin derivative, and the like can be used as they are, but an isobenzofuran derivative is particularly preferably used.

In the present invention, the electron-transporting material needs to efficiently transport electrons from the negative electrode between the electrodes to which an electric field is applied, and has a high electron injection efficiency and a high efficiency of transporting the injected electrons. Is desirable. For this purpose, it is required that the material has a high electron affinity, a high electron mobility, a high stability, and a small amount of impurities serving as traps during production and use. As a substance satisfying such conditions, quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum, tropolone metal complex, flavonol metal complex, perylene derivative, perinone derivative, naphthalene, coumarin derivative, oxadiazole derivative, aldazine derivative,
There are bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives and the like, but there is no particular limitation. These electron transporting materials may be used alone or may be laminated or mixed with different electron transporting materials.

The materials used for the above-described hole transporting layer, light emitting layer and electron transporting layer can be used alone to form each layer. As the polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N- Vinyl carbazole), polymethyl methacrylate, polybutyl methacrylate, 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, phenolic resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin,
It is also possible to use the resin dispersed in a curable resin such as a silicone resin.

In the present invention, the method for forming the luminescent material is not particularly limited, such as resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, and coating. It is preferable in terms of characteristics. The thickness of the layer depends on the resistance of the luminescent material and cannot be limited, but is selected from the range of 1 to 1000 nm.

In the present invention, the electric energy 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,
In consideration of the power consumption and the life of the device, the maximum luminance should be obtained with the lowest possible energy.

In the present invention, a matrix refers to a matrix in which pixels for display are arranged in a lattice, and displays a character or an image by a set of pixels. The shape and size of the pixel depend on the application. For example, a square pixel having a side of 300 μm or less is usually used for displaying images and characters on a personal computer, a monitor, and a television. In the case of a large display such as a display panel, a pixel having a side of mm order is used. . For monochrome display, pixels of the same color may be arranged, but for color display, red, red,
Green and blue pixels are displayed side by side. In this case, there are typically a delta type and a stripe type. The matrix may be driven by either a line-sequential driving method or an active matrix. The line-sequential driving has the advantage that the structure is simpler. However, in consideration of the operation characteristics, the active matrix is sometimes superior, and therefore it is necessary to use the same depending on the application.

In the present invention, the segment type refers to a pattern formed so as to display predetermined information,
Light is emitted from the determined area. For example, there are a time display and a temperature display on a digital clock or a thermometer, an operation state display of an audio device, an electromagnetic cooker, or the like, and a panel display of an automobile. The matrix display and the segment display may coexist in the same panel.

In the present invention, the backlight is mainly used for improving the visibility of a display device which does not emit light, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display panel, a sign, and the like. . In particular, as a backlight for a liquid crystal display device, especially a personal computer application in which thinning is an issue, considering that it is difficult to reduce the thickness because the conventional type is made of a fluorescent lamp or a light guide plate, the present invention The backlight is thin and lightweight.

[0041]

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 (available from Asahi Glass Co., Ltd., 15 Ω / □, electron beam vapor-deposited product) on which an ITO transparent conductive film was deposited to 150 nm was cut into 30 × 40 mm and etched. The obtained substrate was subjected to ultrasonic cleaning with acetone and "Semicocrine 56" (manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, and then with ultrapure water. Subsequently, the substrate was subjected to ultrasonic cleaning with isopropyl alcohol for 15 minutes, immersed in hot methanol for 15 minutes, and dried. Immediately before this element is fabricated,
V-ozone treatment was performed, the apparatus was set in a vacuum evaporation apparatus, and the apparatus was evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁵ Pa or less. By the resistance heating method, 4,4'-
Bis (N- (m-tolyl) -N-phenylamino) biphenyl was deposited to a thickness of 100 nm. Next, triphenylsilyl-2-pyrene was laminated to a thickness of 50 nm as a light emitting material. Next, as an electron transporting material, 2,9-dimethyl-
4,7-diphenyl-1,10-phenanthroline is added to 1
It was laminated to a thickness of 00 nm. Next, 0.5 nm of lithium
After doping the organic layer, aluminum is
A 5 × 5 mm square device was prepared by vapor deposition to form a cathode. The film thickness referred to here is a value indicated by a crystal oscillation type film thickness monitor.
From this light emitting element, an emission wavelength of 471 nm and a luminance of 238
Good blue light emission of 0 candela / square meter was obtained. When the light-emitting element was driven by a 1 mA pulse (duty ratio 1/60, current value at the time of pulse 60 mA) in a vacuum cell, high-intensity blue light emission with good color purity was confirmed.

Example 2 A light emitting device was manufactured in exactly the same manner as in Example 1 except that di (2-pyrenyl) diphenylsilane was used as a light emitting material. From this light emitting device, an emission wavelength of 486 nm and a luminance of 22
Good blue light emission of 90 candela / square meter was obtained.

Example 3 The procedure was the same as in Example 1 up to the deposition of the hole transport material. Next, the light emitting material of Example 1 was used as a host material, and di (2-methylphenyl) isobenzofuran (fluorescence peak wavelength was 468 nm) was used as a dopant material. Evaporated.
Next, a light-emitting element was manufactured in the same manner as in Example 1 from the evaporation of the electron transporting material. From this light emitting element, an EL spectrum similar to the fluorescence spectrum of the dopant material was observed,
High-luminance blue light emission with good color purity was obtained.

Example 4 A glass substrate on which an ITO transparent conductive film was deposited to a thickness of 150 nm
(Asahi Glass Co., Ltd., 15Ω / □, electron beam evaporation product)
Cut to 30 × 40mm, by photolithography
300 μm pitch (remaining width 270 μm) x 32 struts
It was patterned into an ip shape. Long side of ITO stripe
One side is 1.2 to facilitate electrical connection with the outside.
It is expanded to a pitch of 7 mm (opening width 800 μm).
The resulting substrates were acetone and semicocrine 56 for 15
After ultrasonic cleaning for minutes, the substrate was washed with ultrapure water. Then
Ultrasonic cleaning with isopropyl alcohol for 15 minutes and then heat
It was immersed in methanol for 15 minutes and dried. This board
Was subjected to UV-ozone treatment for 1 hour immediately before producing a device.
Installed in an empty vapor deposition device, the degree of vacuum in the device is 5 × 10 ^-Four
It exhausted until it became Pa or less. By the resistance heating method,
4,4'-bis (N- (m-tri
B) -N-phenylamino) biphenyl
And the luminescent material of Example 1 was deposited to a thickness of 50 nm.
Was. Next, 2,9-dimethyl-4,
7-diphenyl-1,10-phenanthroline is added to 100
It was laminated to a thickness of nm. The film thickness mentioned here is a crystal oscillation type film
This is a thickness monitor display value. Next, Kovar with a thickness of 50 μm
16 pieces of 250 μm by wet etching on the plate
Opening (remaining width 50μm, equivalent to 300μm pitch)
The beam mask will be perpendicular to the ITO stripe in vacuum
Replace the mask in such a way that the mask and the ITO substrate adhere
Was fixed with a magnet from the back. And 0.5n of lithium
m after doping the organic layer,
32 × 16 dot matrix device
Was. When this device was driven in matrix,
The characters could be displayed without any clicks.

[0046]

According to the present invention, it is possible to provide a light emitting device having high luminous efficiency and excellent color purity. It is particularly effective for blue light emission.

Claims (8)

[Claims] 1. An element which emits light by electric energy in which a luminescent substance is present between a positive electrode and a negative electrode, wherein the element comprises an organic phosphor having a fluorescent skeleton substituted with a silyl group. Light emitting element. 2. The light emitting device according to claim 1, wherein the organic phosphor having a fluorescent skeleton substituted with a silyl group is represented by the following general formula (1). Embedded image (Where R ^{1 to} R ⁴ are each hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, arylether, arylthioether Group, aryl group, heterocyclic group, halogen, haloalkane, haloalkene, haloalkyne, cyano group, aldehyde group, carbonyl group, carboxyl group,
It is selected from ester groups, carbamoyl groups, amino groups, nitro groups, and siloxanyl groups. At least one of R ^{1 to} R ⁴ is a fluorescent skeleton. ) 3. It has a fluorescent skeleton substituted with a silyl group.
The organic phosphor is represented by the following general formula (2):
The light emitting device according to claim 1, wherein Embedded image(Where R^Five~ R⁷Are hydrogen, alkyl group,
Loalkyl, aralkyl, alkenyl, cycloa
Alkenyl, alkynyl, hydroxyl, mercapto,
Alkoxy group, alkylthio group, aryl ether group,
Reel thioether group, aryl group, heterocyclic group, halogen
Haloalkane, haloalkene, haloalkyne, shea
Group, aldehyde group, carbonyl group, carboxyl group,
Ester groups, carbamoyl groups, amino groups, nitro groups,
It is selected from loxanyl groups. X ¹Indicates a fluorescent skeleton
You. ) 4. The light emitting device according to claim 1, wherein the fluorescent skeleton substituted with a silyl group is represented by the following general formula (3). Embedded image (Where R ^{8 to} R ¹⁰ are each hydrogen, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a mercapto group,
Alkoxy group, alkylthio group, aryl ether group,
Selected from an arylthioether group, an aryl group, a heterocyclic group, a halogen, a haloalkane, a haloalkene, a haloalkyne, a cyano group, an aldehyde group, a carbonyl group, a carboxyl group, an ester group, a carbamoyl group, an amino group, a nitro group, and a siloxanyl group. . X ² represents a fluorescent skeleton. n represents a natural number of 2 or more. ) 5. The light-emitting device according to claim 1, wherein the fluorescent skeleton is a condensed aromatic ring having four or more ring structures. 6. The light emitting device according to claim 1, wherein said organic phosphor is a light emitting material. 7. The light emitting device according to claim 1, wherein said organic phosphor is an electron transporting material. 8. The light emitting device according to claim 1, wherein the light emitting device is a display for displaying in a matrix and / or a segment system.