JP2000208272A - Light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a red light emitting element having high color purity by including at least a styryl heterocyclic derivative having a fluorescence peak wave length being in a specific range and a compound having a pyrromethene skeleton or the metallic complex. SOLUTION: A light emitting material emits the light in a peak wave length of 580 nm to 720 nm by electric energy. This light emitting material includes a styryl heterocyclic derivative having a fluorescence peak wave length of 540 nm to 720 nm and a compound having a pyrromethene skeleton or the metallic complex. The pyrromethene skeleton is expressed by the formula. In the formula, R1 to R7 may be the same or may be different, and are hydrogen, alkyl, alkoxy, halogen, aryl, aralkyl, alkenyl or the like, X is carbon or nitrogen, but in the case of nitrogen, R7 does not exist. B, Be, Mg, Cr, Fe, Co, Ni, Cu, Zn, Pt or the like are preferably cited as metal capable of coordinating with the metallic complex.

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] Among multicolor light emission, red light emission has been studied as a useful light emission color. Conventionally, perylene-based such as bis (diisopropylphenyl) perylene, perinone-based, porphyrin-based, Eu complex (Chem. Lett., 1267)
(1991)) are known as red light emitting materials.

As a technique for obtaining red light emission, a method of mixing a small amount of a red fluorescent material as a dopant into a host material is also being studied. As the host material, tris (8-quinolinolato) aluminum complex, bis (1
0-benzoquinolinolato) beryllium complex, diarylbutadiene derivative, stilbene derivative, benzoxazole derivative, benzothiazole derivative and the like,
4- (dicyanomethylene)-as a dopant therein
2-methyl-6- (p-dimethylaminostyryl) -4
H-pyran, metal phthalocyanine (MgPc, AlPc
Cl), a squarylium compound and a biolanthrone compound were used to emit red light.

[0006]

However, conventional red light-emitting materials (host material and dopant material) have a wide peak width even if the emission peak wavelength exceeds 580 nm,
The color purity was poor, and beautiful red light emission could not be obtained. Also,
A rare-earth complex such as an Eu complex has a narrow emission peak width and can provide clean red light emission, but has a maximum luminance of several to several tens of cd / m.
^The problem was that clear display was not possible due to the low value of ² .

An object of the present invention is to solve such a problem and to provide a red light emitting device having high color purity.

[0008]

According to the present invention, there is provided an element which emits light having a peak wavelength of 580 nm or more and 720 nm or less due to electric energy, wherein a substance responsible for light emission is present between the anode and the cathode. Wavelength 540
A light-emitting element including a styryl heterocyclic derivative having a size of from nm to 720 nm and a compound having a pyromethene skeleton or a metal complex thereof.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the anode 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.

The cathode is not particularly limited as long as it can efficiently inject electrons into the organic material layer.
Gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium, magnesium, etc., and lithium, sodium for improving the electron injection efficiency and improving the device characteristics , Potassium, calcium, magnesium or alloys containing these low work function metals are effective. But,
These low work function metals are generally unstable in the air in many cases. For example, an organic layer is doped with a very small amount of lithium or magnesium (1 nm or less as indicated by a film thickness gauge by vacuum deposition) to have high stability. Although a method using an electrode can be mentioned as a preferable example, it is not particularly limited because an inorganic salt such as lithium fluoride can be used. In addition, platinum, gold,
Lamination of metals such as 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, and hydrocarbon polymers. Are preferred examples. 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.

The substance which controls light emission includes 1) a hole transport layer / light-emitting layer, 2) a hole transport layer / light-emitting layer / electron transport layer, 3) a light-emitting layer / electron transport layer, and 4) a combination of the above. Any of the forms in which the combined substances are mixed together may be used. That is, as the element configuration, in addition to the multilayer laminated structure of the above 1) to 3), a single layer of a luminescent material alone or a layer containing a luminescent material and a hole transporting material or an electron transporting material may be provided as in 4).

The hole transporting layer is formed of a hole transporting substance alone or a mixture of two or more substances or a mixture of a hole transporting substance and a polymer binder. N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diphenyl-1,1'-diamine, N, N'-dinaphthyl-N, N'-diphenyl-
Triphenylamines such as 4,4′-diphenyl-1,1′-diamine, bis (N-allylcarbazole) or bis (N-alkylcarbazole), pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadi Heterocyclic compounds represented by azole derivatives, phthalocyanine derivatives, porphyrin derivatives, and polymer-based polycarbonates and styrene derivatives having the above monomers in the side chain, polyvinylcarbazole, polysilane, and the like are preferable. However, the compound is not particularly limited as long as it can inject holes from the anode and can transport holes.

The light-emitting material emits light at a peak wavelength of 580 nm to 720 nm due to electric energy. 58
If it is 0 nm or less, red light emission with good color purity cannot be obtained even if the peak width is narrow, and if it is 720 nm or more, high visibility red light emission cannot be obtained because of poor visibility.

The light emitting material has a fluorescence peak wavelength of 540.
a compound having a pyrrolethene skeleton (also known as a diazaindacene skeleton) or a metal complex thereof with a styryl heterocyclic derivative having a size of from nm to 720 nm, a fluorescent compound as a host material, and a compound having a pyromethene skeleton or a metal complex thereof as a dopant material. The doping method used can be mentioned as a preferable method.
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.

Energy transfer from the host material to the dopant material requires an overlap between the fluorescence spectrum of the host material and the absorption spectrum (excitation spectrum) of the dopant material. In addition, the Stokes shift (difference between the peak of the excitation spectrum and the peak of the fluorescence spectrum) of the dopant material having good color purity is as narrow as several to several tens of nm, so as to obtain high color purity red light emission from the dopant material of 580 nm to 720 nm. Then, the absorption spectrum (excitation spectrum) of the dopant material becomes yellow, yellow-orange, orange, red-orange, and red regions (540 nm or more and 720 nm or less). When the fluorescence spectrum of the host material is in the yellow-green, green, blue-green, blue, blue-violet, and violet regions on the shorter wavelength side than yellow and the spectrum overlap is small, energy transfer is not performed quickly, and the Light emission cannot be obtained, or even if light emission is obtained, light emission from the host material remains and red light emission of high color purity such as whitening cannot be obtained. In addition, there is an example in which a diazaindacene derivative is used as a dopant material (see JP-A-9-208946 and JP-A-9-208946).
JP-A-118880), and each of the host materials is different from the present invention. On the other hand, since a blue light emitting material is used as the host material, the overlap of spectra is small and energy transfer is not sufficiently performed. Blue light emission is mixed with light emission from the dopant material, and only white light emission is obtained (Japanese Patent Application Laid-Open No. 9-208946). On the other hand, since a green light-emitting material is used as the host material, the light emission becomes green rather than red, which is also a luminescent material, which is not the object of the present invention (Japanese Unexamined Patent Publication No. Hei 9-118880). ).

[0016] For the above reasons, 580 nm or more and 720
In order for the dopant material to emit light with high brightness and high color purity at nm or less, the host material needs to have a fluorescence peak wavelength of 540 nm or more and 720 nm or less. As a guide, those having fluorescence such as yellow, yellow-orange, orange, red-orange, and red correspond.

The fluorescence peak wavelength is 540 nm or more and 720 n
Preferred examples of the host material having a fluorescence peak wavelength of m or less include a styryl heterocyclic derivative. The styryl heterocyclic derivative is a compound in which one or more substituted or unsubstituted styryl groups are substituted on the heterocyclic ring, and the derivative in which the heterocyclic ring has at least one of oxygen, nitrogen and sulfur is preferably used. . Specific examples of the heterocyclic ring are not particularly limited, but include pyridine, pyrazine, triazine, thiophene, furan, pyrrole,
Oxazole, oxadiazole, imidazole, triazole, thiazole, thiadiazole and the like can be mentioned. This heterocyclic ring may have a substituent other than the styryl group introduced. If the fluorescence peak wavelength of the basic skeleton of the styryl heterocyclic derivative itself is 540 nm or more and 720 nm or less, it is not always necessary to modify, but if the fluorescence peak wavelength is 540 nm or less or in order to efficiently transfer energy with the dopant. When it is desired to increase the wavelength, at least one of an aromatic ring and a heterocyclic ring is introduced as a substituent to the heterocyclic ring and / or styryl group of the basic skeleton, or is condensed, or included in the basic skeleton of the fluorescent compound. By substituting the ring structure with a heterocyclic ring, the wavelength can be made longer, and it can be more suitably used as a host material. In the case where at least one of an aromatic ring and a heterocyclic ring is introduced as a substituent into the basic skeleton or condensed, introduction of the basic skeleton itself as a substituent and condensation thereof are also included.

Further, as the styryl heterocyclic derivative, a compound in which the heterocyclic ring is pyrazine or thiophene can be more preferably used because of its excellent light emitting properties. Specific examples of the styryl heterocyclic derivative include, but are not particularly limited to, the following compounds.

[0019]

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[0020]

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[0021]

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Preferred examples of the dopant include compounds having a pyromethene skeleton (also known as diazaindacene skeleton) represented by the following general formula (1).

[0023]

Embedded image (Where R1 to R7 may be the same or different,
Hydrogen, alkyl, alkoxy, halogen, aryl, aralkyl, alkenyl, aryl ether, heterocycle, cyano, aldehyde, carbonyl, ester, carbamoyl, amino, condensed ring and aliphatic ring formed between adjacent substituents Selected from. X is carbon or nitrogen, but when it is nitrogen, R7 is not present. ).

In the description of these substituents, the alkyl group means a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group and a butyl group, which may be unsubstituted or substituted. Absent. 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. Halogen refers to fluorine, chlorine, bromine and iodine. Further, the aryl group is, for example, a phenyl group, a naphthyl group, a biphenyl group, a phenanthryl group,
It represents an aromatic hydrocarbon group such as a terphenyl group and a pyrenyl group, 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 refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, an allyl group and a butadienyl group, which may be unsubstituted or substituted. 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. Also,
The heterocyclic group is, for example, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group,
A cyclic structure group having an atom other than carbon, such as a pyridyl group, a pyrazyl group, a pyrimidyl group, a quinolinyl group, an isoquinolyl group, a quinoxalyl group, an acridinyl group, and a carbazolyl group, may be unsubstituted or substituted. 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 fused ring and the aliphatic ring formed between the adjacent substituents include R1 and R2, R2 and R3, R4 and R5,
A conjugated or non-conjugated condensed ring is formed at the position of 5 and R6. These condensed rings may contain nitrogen, oxygen and sulfur atoms in the ring structure, or may be condensed with another ring.

When coordinating to a metal, the compound having a pyrromethene skeleton alone or a mixed ligand is not particularly limited. As the second ligand in the case of the mixed ligand,
It is possible to introduce alkoxy, phenoxy, halogen, alkyl, allyl and other condensed ring hydrocarbons, heterocyclic compounds, or aromatic or heterocyclic compounds linked via an oxygen atom.

The metal that can be coordinated with the ligand of the present invention is not particularly limited. Examples of commonly used elements include boron, beryllium, magnesium, chromium, iron, cobalt, nickel, copper, zinc, platinum, and the like. And the like.

In order to obtain red light emission having excellent color purity characteristics, a compound represented by the following general formula (2) is desirable among the compounds having a pyromethene skeleton.

[0028]

Embedded image (Where at least one of R8 to R14 contains an aromatic ring or forms a condensed aromatic ring with an adjacent substituent, and the rest is hydrogen, alkyl, alkoxy, halogen, aryl, aralkyl, alkenyl, aryl ether,
Heterocycle, cyano, aldehyde, carbonyl, ester,
It is selected from carbamoyl, amino, fused ring and aliphatic ring formed between adjacent substituents. X is carbon or nitrogen, but when it is nitrogen, R14 is not present. ).

The aromatic ring group mentioned here includes not only aromatic hydrocarbon groups such as phenyl group, naphthyl group and anthranyl group but also heterocyclic aromatic functional groups such as pyridyl group, quinolyl group and thienyl group. . The fused aromatic ring formed between adjacent substituents is R8 and R9, R9 and R1
A condensed aromatic ring is formed at the positions of 0, R11 and R12, and R12 and R13. And these fused aromatic rings are
Like the above-mentioned aromatic ring group, the ring structure may contain nitrogen, oxygen and sulfur atoms, or may be condensed with another aromatic or aliphatic ring.

Further, when a compound having a pyrromethene skeleton is used as a red light emitting material, a compound having a high fluorescence quantum yield is more preferable in order to obtain high luminance characteristics. Therefore, as the compound having a pyromethene skeleton, a compound represented by the following general formula (3) is more preferable.

[0031]

Embedded image (Here, at least one of R15 to R21 contains an aromatic ring or forms a condensed aromatic ring with an adjacent substituent, and the rest is hydrogen, alkyl, alkoxy, halogen,
It is selected from aryl, aralkyl, alkenyl, aryl ether, heterocycle, cyano, aldehyde, carbonyl, ester, carbamoyl, amino, condensed ring and aliphatic ring formed between adjacent substituents. R22 and R23 may be the same or different, and halogen,
Selected from hydrogen, alkyl, aryl, and heterocyclic groups. X
Is carbon or nitrogen, and in the case of nitrogen, the above R21
Does not exist. ).

Specific examples of the compound having a pyromethene skeleton include the following structures.

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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When the doping amount is usually too large, a concentration quenching phenomenon occurs.
It is preferably used in the following, more preferably 2% or less. As a doping method, it can be formed by a co-evaporation method with a host material, but it may be mixed with the host material in advance and then evaporated at the same time. Further, since the compound having a diazaindacene skeleton emits light even in a very small amount, it is possible to use a small amount of a diazaindacene derivative sandwiched between host materials. In this case, one or more layers may be stacked with the host material.

The dopant material to be added to the light-emitting material is not limited to one kind of the compound having a pyrromethene skeleton. A plurality of the above compounds may be used as a mixture, or one or more kinds of known dopant materials may be used as the above-mentioned compound. May be used as a mixture. Specifically, conventionally known naphthalimide derivatives such as bis (diisopropylphenyl) perylenetetracarboxylic imide, perinone derivatives, rare earth complexes such as Eu complexes having acetylacetone, benzoylacetone and phenanthroline as ligands, 4- (dicyanomethylene) -2-methyl-6- (p
-Dimethylaminostyryl) -4H-pyran and its analogs, metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine, rhodamine compounds, deazaflavin derivatives, coumarin derivatives, oxazine compounds and the like can coexist, but are not particularly limited thereto. Not something.

As the electron transporting material in the present invention,
It is necessary to efficiently transport electrons from the negative electrode between the electrodes to which an electric field is applied, and it is desirable that the electron injection efficiency is high and the injected electrons are transported efficiently. 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. Materials satisfying such conditions include quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, tropolone metal complexes, flavonol metal complexes, perylene derivatives, perinone derivatives, naphthalene,
There are coumarin derivatives, oxadiazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, and the like, but are not particularly limited. Although these electron transport materials are used alone,
They may be laminated or mixed with different electron transport materials.

The above materials used for the hole transporting layer, the light emitting layer and the electron transporting layer can be used alone to form the respective layers. 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.

The method of forming the substance that controls light emission is not particularly limited, such as resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination, and coating. However, resistance heating evaporation and electron beam evaporation are generally used. Preferred in terms of surface. The thickness of the layer depends on the resistance value of the substance that controls light emission and cannot be limited, but is selected from the range of 1 to 1000 nm.

In order to perform a beautiful red display, it is important that the peak wavelength of the emission spectrum is in the range of 580 nm to 720 nm, more preferably, 600 nm to 700 nm, and the half width is 100 nm or less. . The emission spectrum is preferably a single peak as much as possible. In some cases, the emission spectrum may have a plurality of maximum points due to overlap with another peak, or a shoulder may appear at the foot of the peak. In the present invention, the peak wavelength is defined as the wavelength of the main peak corresponding to the emission center wavelength, and the half-value width is defined as the peak width at half the height of the emission center wavelength in all of these peaks.

The electric energy mainly refers to a direct current, but a pulse current or an alternating current can also be used.
The current value and the voltage value are not particularly limited. However, in consideration of the power consumption and life of the device, it is necessary to obtain the maximum luminance with the lowest possible energy.

The matrix in the present invention 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, but the active matrix is sometimes superior when the operating characteristics are taken into consideration.

The segment type in the present invention means that a pattern is 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.

The backlight in the present invention 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.

[0050]

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 / □, electron beam evaporated product, manufactured by Asahi Glass Co., Ltd.) on which an ITO transparent conductive film was deposited to a thickness of 150 nm
The wafer was cut into a size of 40 mm and etched. The obtained substrate was subjected to ultrasonic cleaning with acetone and semicocrine 56 for 15 minutes each, 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. This substrate was subjected to UV-ozone treatment for one hour immediately before producing the element, placed in a vacuum evaporation apparatus, and evacuated until the degree of vacuum in the apparatus became 1 × 10 ⁻⁵ Pa or less. First, 100 nm of N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (TPD) was deposited as a hole transporting material by a resistance heating method. . Next, 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine (fluorescence of the powder is orange) as a host material and 4,4-difluoro-1,3,5,7-tetraphenyl- as a dopant material. 4
Using co-bora-3a, 4a-diaza-s-indacene (fluorescence peak wavelength in a dichloromethane solution is 611 nm), co-evaporating the dopant to a thickness of 50 nm so that the dopant becomes 1 wt%, and depositing a host material having a thickness of 50 nm. It was layered.
Next, 0.2 nm of lithium and 150 nm of silver were vapor-deposited and used as a cathode to produce a 5 × 5 mm square device. The emission peak wavelength of this light emitting device was 609 nm, and the device exhibited a beautiful red emission having a spectral half width of 52 nm.

Comparative Example 1 A light emitting device was produced in the same manner as in Example 1 except that a tris (8-quinolinolato) aluminum complex (fluorescence peak wavelength: 513 nm) was used as a host material. This light-emitting element had an emission peak wavelength of 520 nm, showed almost no energy transfer to the dopant material, showed green light emission from the host material, and failed to obtain red light emission from the dopant material.

Example 2 A light emitting device was manufactured in the same manner as in Example 1 except that 2,3,5-tris [2- (phenyl) vinyl] pyrazine (the fluorescence of the powder was yellow) was used as the host material. This light-emitting device emitted light at a peak wavelength of 610 nm and exhibited a beautiful red light emission having a spectral half width of 50 nm.

Example 3 A light emitting device was prepared in the same manner as in Example 1 except that 2,3,5-tris [2- (4-trifluoromethylphenyl) vinyl] pyrazine (the fluorescence of the powder was yellow) was used as the host material. Was prepared. The emission peak wavelength of this light emitting device is 610.
nm and a beautiful red emission having a spectral half width of 50 nm.

Example 4 A light emitting device was produced in the same manner as in Example 1 except that 2,3,5-tris [2- (4-chlorophenyl) vinyl] pyrazine (the fluorescence of the powder was yellow) was used as the host material. . This light-emitting device emitted light at a peak wavelength of 610 nm and exhibited a beautiful red light emission having a spectral half width of 50 nm.

Example 5 As a host material, 2,3,5,6-tetrakis [2-
A light-emitting device was produced in the same manner as in Example 1 except that (phenyl) vinyl] pyrazine (the fluorescence of the powder was yellow). This light-emitting device emitted light at a peak wavelength of 610 nm and exhibited a beautiful red light emission having a spectral half width of 50 nm.

Example 6 Light emission was performed in the same manner as in Example 1 except that 2,5-bis [2- (4-diphenylaminophenyl) vinyl] -3-methylthiophene (the fluorescence of the powder was yellow) was used as the host material. An element was manufactured. This light-emitting device emitted light at a peak wavelength of 610 nm and exhibited a beautiful red light emission having a spectral half width of 50 nm.

Example 7 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 1 except that [N ¹ , N ² ] boron (fluorescence peak wavelength in a dichloromethane solution was 645 nm). This light-emitting device emitted light at a peak wavelength of 646 nm and exhibited a beautiful red light emission having a spectral half width of 40 nm.

Example 8 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 2 except that [N ¹ , N ² ] boron was used. The emission peak wavelength of this light emitting device is 6
It was 46 nm, and showed a beautiful red emission having a spectral half width of 40 nm.

Example 9 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 3, except that [N ¹ , N ² ] boron was used. The emission peak wavelength of this light emitting device is 6
It was 46 nm, and showed a beautiful red emission having a spectral half width of 40 nm.

Example 10 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 4 except that [N ¹ , N ² ] boron was used. The emission peak wavelength of this light emitting device is 6
It was 46 nm, and showed a beautiful red emission having a spectral half width of 40 nm.

Example 11 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 5, except that [N ¹ , N ² ] boron was used. The emission peak wavelength of this light emitting device is 6
It was 46 nm, and showed a beautiful red emission having a spectral half width of 40 nm.

Example 12 Difluoro [3-phenyl-1- as a dopant material
[(3-phenyl-2H-benzo [c] isoindole-1
-Yl) methylene] -1H-benzo [c] isoindolato-
A light emitting device was manufactured in the same manner as in Example 6, except that [N ¹ , N ² ] boron was used. The emission peak wavelength of this light emitting device is 6
It was 46 nm, and showed a beautiful red emission having a spectral half width of 40 nm.

Example 13 A glass substrate (15 Ω / □, electron beam evaporated product, manufactured by Asahi Glass Co., Ltd.) on which an ITO transparent conductive film was deposited to a thickness of 150 nm
Cut to × 40mm, 30 by photolithography
The pattern was processed into a stripe pattern of 0 μm pitch (remaining width 270 μm) × 32 stripes. One side of the long side of the ITO stripe is 1.27 to facilitate electrical connection with the outside.
mm pitch (opening width 800 μm). The obtained substrate was subjected to ultrasonic cleaning with acetone and semicocrine 56 for 15 minutes each, 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. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the element, and was placed in a vacuum evaporation apparatus, and the degree of vacuum in the apparatus was 5 × 10 ^-4 P
The gas was exhausted until the pressure became equal to or less than a. First, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (T
PD) was deposited to a thickness of 100 nm. Next, 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine was used as a host material, and 4,4-difluoro-1,3,
Using 5,7-tetraphenyl-4-bora-3a, 4a-diaza-s-indacene, the dopant is co-deposited to a thickness of 50 nm so that the concentration of the dopant becomes 1 wt%.
It was laminated to a thickness of nm. Next, a mask provided with 16 openings of 250 μm (corresponding to a remaining width of 50 μm and a pitch of 300 μm) provided on a 50 μm-thick Kovar plate by wet etching is exchanged in a vacuum so as to be orthogonal to the ITO stripes. It was fixed with a magnet from the back so that the and the ITO substrate were in close contact with each other. And 50 magnesium
A 32 × 16 dot matrix element was prepared by vapor deposition of 150 nm and aluminum. When this device was driven in a matrix, characters could be displayed without crosstalk.

[0065]

According to the present invention, it is possible to provide a red light emitting device having high utilization efficiency of electric energy and excellent color purity.

Claims (12)

[Claims] An element which emits light having a peak wavelength of 580 nm or more and 720 nm or less by electric energy between a positive electrode and a cathode and emits light having a peak wavelength of 580 nm or more and 720 nm or less. A light-emitting element comprising a styryl heterocyclic derivative and a compound having a pyromethene skeleton represented by the following general formula (1) or a metal complex thereof. Embedded image (Where R1 to R7 may be the same or different,
Hydrogen, alkyl, alkoxy, halogen, aryl, aralkyl, alkenyl, aryl ether, heterocycle, cyano, aldehyde, carbonyl, ester, carbamoyl, amino, condensed ring and aliphatic ring formed between adjacent substituents Selected from. X is carbon or nitrogen, but when it is nitrogen, R7 is not present. ) 2. The method according to claim 1, wherein the metal of the metal complex is boron, beryllium, magnesium, chromium, iron, cobalt, nickel,
The light-emitting device according to claim 1, wherein the light-emitting device is at least one selected from copper, zinc, and platinum. 3. The light emitting device according to claim 1, wherein the compound having a pyromethene skeleton is represented by the following general formula (2). Embedded image (Where at least one of R8 to R14 contains an aromatic ring or forms a condensed ring with an adjacent substituent,
The remainder is hydrogen, alkyl, alkoxy, halogen, aryl, aralkyl, alkenyl, aryl ether, heterocycle, cyano, aldehyde, carbonyl, ester, carbamoyl, amino, condensed and aliphatic rings formed between adjacent substituents Selected from X is carbon or nitrogen, but when it is nitrogen, R14 is not present. ) 4. The light emitting device according to claim 1, wherein the compound having a pyromethene skeleton is represented by the following general formula (3). Embedded image (Here, at least one of R15 to R21 contains an aromatic ring or forms a condensed aromatic ring with an adjacent substituent, and the rest is hydrogen, alkyl, alkoxy, halogen,
It is selected from aryl, aralkyl, alkenyl, aryl ether, heterocycle, cyano, aldehyde, carbonyl, ester, carbamoyl, amino, condensed ring and aliphatic ring formed between adjacent substituents. R22 and R23 may be the same or different, and halogen,
Selected from hydrogen, alkyl, aryl, and heterocyclic groups. X
Is carbon or nitrogen, and in the case of nitrogen, the above R21
Does not exist. ) 5. The light emitting device according to claim 1, wherein the heterocyclic ring of the styryl heterocyclic derivative contains at least one of nitrogen, oxygen and sulfur. 6. The method according to claim 1, wherein the heterocycle of the styryl heterocycle derivative is pyrazine or thiophene.
The light-emitting element according to any one of the preceding claims. 7. The light emitting device according to claim 1, wherein the compound having a pyromethene skeleton or a metal complex compound thereof is a dopant material. 8. The light emitting device according to claim 1, wherein the substance that controls light emission comprises at least a light emitting material and a hole transporting material and / or an electron transporting material. 9. The light-emitting substance according to claim 1, wherein the light-emitting substance has a laminated structure of at least a hole transport layer and a light-emitting layer.
The light-emitting element according to any one of the preceding claims. 10. The light emitting device according to claim 9, wherein an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially laminated. 11. The light emitting device according to claim 1, wherein the display is a display for displaying in a matrix and / or a segment system. 12. The light emitting device according to claim 1, wherein the light emitting device is a backlight.