JP4710268B2 - Pyromethene compound, light emitting device material and light emitting device using the same - Google Patents

Description

  The present invention relates to a pyromethene compound useful as a fluorescent dye and a light emitting device using the same.

  In recent years, research on an organic laminated thin film light emitting device in which light is emitted when electrons injected from a cathode and holes injected from an anode are recombined in an organic phosphor sandwiched between both electrodes has been actively conducted. This element is attracting attention because it is thin, has high luminance emission under a low driving voltage, and multicolor emission by selecting a fluorescent material.

This study was conducted by Kodak C.I. W. Since Tang et al. Have shown that organic multilayer thin-film elements emit light with high brightness, many research institutions have studied. A typical structure of an organic laminated thin film light emitting device presented by a research group of Kodak Company is a hole transporting diamine compound on an ITO glass substrate, 8-hydroxyquinoline aluminum as a light emitting layer, and Mg: Ag as a cathode. These were sequentially provided, and green light emission of 1000 cd / m ² was possible with a driving voltage of about 10 V (see, for example, Non-Patent Document 1). Some of the present organic laminated thin film light emitting elements have different configurations such as those provided with an electron transport layer in addition to the above element constituent elements.

  Among multicolor emission, red emission is being studied as a useful emission color. Conventionally, perylene-based materials such as bis (diisopropylphenyl) perylene, perinone-based materials, porphyrin-based materials, Eu complexes, and the like are known as red light-emitting materials (for example, see Non-Patent Document 2).

  In addition, as a technique for obtaining red light emission, a method of mixing a small amount of a red fluorescent material as a dopant in a host material has been studied. Examples of the host material include tris (8-quinolinolato) aluminum complex, bis (10-benzoquinolinolato) beryllium complex, diarylbutadiene derivative, stilbene derivative, benzoxazole derivative, benzothiazole derivative, and the like. Red light emission is extracted by the presence of 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -H-pyran, metal phthalocyanine (MgPc, AlPcCl, etc.) compounds, squarylium compounds, and violanthrone compounds. It was.

Further, as a light-emitting material, particularly a dopant, a pyromethene compound that is a compound exhibiting high-luminance emission is known (see, for example, Patent Document 1). In addition, it is also known that red light emission is exhibited by introducing an aromatic ring or the like into the pyromethene skeleton, and the current efficiency is a maximum of 5.1 cd / A (see, for example, Patent Document 2).
“Appl. Phys. Lett.”, 51 (12) 21, p. 913 (1987) “Chem. Lett.”, P. 1267 (1991) Japanese Patent Laid-Open No. 9-118880 JP 2003-12676 A

  Currently, further improvement in light emission efficiency and device life and reduction in power consumption are demanded, and light emitting materials (host materials and dopant materials) used in the prior art have insufficient properties. In particular, the device life is crystallized due to heat generated from the device by energization for a long time, and the device life is shortened. On the other hand, a material imparted with an amorphous property to suppress this crystallization has a poor sublimation property, so that the vacuum vapor deposition temperature (synonymous with the sublimation temperature) of the light emitting material becomes higher than the decomposition temperature. There is a problem that modification such as polymerization occurs. Of the three primary colors required for full-color displays, high-performance light-emitting materials have been found for green light emission, but blue and red, especially red, have sufficient characteristics, especially high brightness, high color purity, and long life. Some luminescent materials have not been obtained.

  The present invention solves such problems of the prior art, a novel pyromethene compound capable of forming a light emitting element without being decomposed during vacuum deposition, having high luminous efficiency, excellent color purity, and having a long element lifetime, and the same Provided is a light emitting element using the above.

That is, the present invention is a pyromethene compound represented by the general formula (1).

^(R 1 to R ² are hydrogen ^.R 3 to R ⁴ is .A r ⁵ is the following formula ^.Ar 1 ~ Ar ⁴ is a fluorine para-position represents a phenyl group substituted with a methyl group (3 ).

(R ¹¹ and R ¹³ are hydrogen. R ¹² is selected from hydrogen, methyl group, methoxy group, and t-butyl group. R ¹⁰ and R ¹⁴ may be the same or different, Although selected from methoxy ^{group, when R 10} and ^{R 14} is hydrogen at the same time, ^{R 12} is a methyl group, a methoxy group, selected et or t- butyl group.))
The present invention is a pyrromethene compound represented by the general formula (1).

^(R 1 to R ² are hydrogen ^.R 3 to R ⁴ is .A r ⁵ is the following general formula ^.Ar 1 ~ Ar ⁴ is a fluorine represents a phenyl group para substituted with t- butyl group It is represented by (4).

(R ¹⁶ and R ¹⁸ are hydrogen. R ¹⁷ is selected from hydrogen, a methyl group, a methoxy group, and a t-butyl group. R ¹⁵ and R ¹⁹ may be the same or different. well, hydrogen is chosen et or methoxy group.))
Furthermore, the present invention is a light emitting device in which a light emitting layer exists between an anode and a cathode and emits light by electric energy, and the light emitting device contains a pyromethene compound represented by the general formula (1). It is.

  The present invention can provide a highly fluorescent pyromethene compound that can be used in a light-emitting element or the like. Further, by using the pyromethene compound of the present invention, it is possible to provide a light-emitting element that does not undergo modification such as decomposition or polymerization at the time of vacuum vapor deposition and has high luminous efficiency, high color purity, and long life.

  A general pyromethene compound is represented by the following general formula (5).

R ²⁰ , R ²¹ and L may be the same or different and are hydrogen, alkyl, cycloalkyl, aralkyl, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, aryl Ether group, 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, silyl group, siloxanyl A fused ring formed between a group, an adjacent substituent and an aliphatic ring. M represents an m-valent metal and is at least one selected from boron, beryllium, magnesium, chromium, iron, nickel, copper, zinc, platinum, and aluminum. Ar ^{6 to} Ar ¹⁰ represent an aryl group.

  Among these substituents, the alkyl group represents a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, and a t-butyl group, which may be unsubstituted or substituted. Absent. The cycloalkyl group represents a saturated alicyclic hydrocarbon group such as cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl, and the like, which may be unsubstituted or substituted. The aralkyl group is an aromatic hydrocarbon group via an aliphatic hydrocarbon such as a benzyl group or a phenylethyl group, and both the aliphatic hydrocarbon and the aromatic hydrocarbon may be unsubstituted or substituted. It doesn't matter. The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, 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, or a cyclohexene group, which may be unsubstituted or substituted. . The alkynyl group refers to 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 a group in which an oxygen atom of an ether bond of an alkoxy group is substituted with a sulfur atom. 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. The arylthioether group is a group in which the oxygen atom of the ether bond of the arylether group is substituted with a sulfur atom. The aryl group represents an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenyl group, a phenanthryl group, a terphenyl group, or a pyrenyl group, which may be unsubstituted or substituted. The heterocyclic group is 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, or a carbazolyl group, which may be unsubstituted or substituted. Absent. Halogen is fluorine, chlorine, bromine or iodine. Haloalkane, haloalkene, haloalkyne means, for example, a part or all of the above-mentioned alkyl group, alkenyl group, alkynyl group such as trifluoromethyl group substituted with the above-mentioned halogen, and the remaining part may be unsubstituted It may be replaced. Aldehyde groups, carbonyl groups, ester groups, carbamoyl groups, amino groups include those substituted with aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, heterocyclic rings, etc. The cyclic hydrocarbon, aromatic hydrocarbon and heterocyclic ring may be unsubstituted or substituted. A silyl group refers to a silicon compound group such as a trimethylsilyl group, which may be unsubstituted or substituted. The siloxanyl group refers to a silicon compound group via an ether bond such as a trimethylsiloxanyl group, which may be unsubstituted or substituted. The condensed ring or aliphatic ring formed between adjacent substituents may be unsubstituted or substituted.

  In addition, among the compounds represented by the general formula (5), the present invention is a boron complex represented by the general formula (1) of the pyromethene compound having a decomposition temperature higher than the sublimation temperature, and the fluorescence quantum yield is high. preferable.

R ^{1 to} R ⁴ may be the same or different, and are hydrogen, alkyl group, cycloalkyl group, aralkyl group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, mercapto group, alkoxy group, alkylthio group, aryl ether group. , 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, silyl group, siloxanyl group, It is selected from fused rings and aliphatic rings formed between adjacent substituents. Ar ^{1 to} Ar ⁵ represent an aryl group.

  About these substituents, it is the same as that of description of the said General formula (5).

Ar ^{1 to} Ar ⁴ represents an unsubstituted or substituted aryl group. Among these Ar ^{1 to} Ar ⁴ , at least one, preferably two or more, more preferably all are methyl, methoxy, t-butyl. Group, unsubstituted or phenyl group having at least one substituent selected from methyl, methoxy, and t-butyl, unsubstituted, or at least one substituted from methyl, methoxy, and t-butyl. When substituted with a phenoxy group having a group, heat resistance higher than the vacuum deposition temperature is maintained, dispersibility in the thin film is improved, and high luminance light emission is obtained. Particularly, Ar ^{1 to} Ar ⁴ are preferably substituted with a methyl group, a methoxy group, or a t-butyl group from the viewpoints of light emission characteristics and heat resistance.

Ar ⁵ represents an unsubstituted or substituted aryl group, and preferably has the following structure from the viewpoint of light emission characteristics and heat resistance. Ar ⁵ is a phenyl group, an unsubstituted or methyl group, a methoxy group, t, wherein at least one of Ar ^{1 to} Ar ⁴ is unsubstituted or has at least one substituent selected from a methoxy group and a t-butyl group. -When substituted with one or more substituents selected from phenoxy groups having at least one substituent among butyl groups, it is preferably represented by the following general formula (2).

R ^{5 to} R ⁹ may be the same or different, and are at least one selected from hydrogen, methyl group, methoxy group, t-butyl group, unsubstituted or methyl group, methoxy group, t-butyl group It is selected from a phenyl group having a group, an unsubstituted group, or a phenoxy group having at least one substituent among a methyl group, a methoxy group, and a t-butyl group.

In Ar ⁵ , when at least one of Ar ^{1 to} Ar ⁴ is substituted with one or more substituents selected from a methyl group and a methoxy group, Ar ⁵ is represented by the following general formula (3). It is preferable to be represented by

R ^{11 to} R ¹³ may be the same or different, and are at least one selected from hydrogen, methyl group, methoxy group, t-butyl group, unsubstituted or methyl group, methoxy group, and t-butyl group It is selected from a phenyl group having a group, an unsubstituted group, or a phenoxy group having at least one substituent among a methyl group, a methoxy group, and a t-butyl group. R ¹⁰ and R ¹⁴ may be the same or different, and have at least one substituent selected from hydrogen, methoxy group, t-butyl group, unsubstituted or methyl group, methoxy group, and t-butyl group A phenyl group, an unsubstituted group, or a phenoxy group having at least one substituent is selected from a methyl group, a methoxy group, and a t-butyl group. When R ¹⁰ and R ¹⁴ are simultaneously hydrogen, R ¹¹ At least one of ˜R ¹³ is a methyl group, a methoxy group, a t-butyl group, an unsubstituted group or a phenyl group having at least one substituent selected from a methyl group, a methoxy group, and a t-butyl group, an unsubstituted group, or A phenoxy group having at least one substituent is selected from a methyl group, a methoxy group, and a t-butyl group.

Further, Ar ⁵ described ^above, when it is substituted with at least one of t- butyl group among Ar 1 to Ar ^4, Ar ⁵ is is preferably represented by the following general formula (4).

R ^{16 to} R ¹⁸ may be the same or different, and have at least one substituent selected from hydrogen, methyl group, methoxy group, t-butyl group, unsubstituted or methoxy group, t-butyl group It is selected from a phenyl group, an unsubstituted group, or a phenoxy group having at least one substituent among a methyl group, a methoxy group, and a t-butyl group. R ¹⁵ and R ¹⁹ may be the same or different from each other, and at least one selected from hydrogen, methoxy group, t-butyl group, unsubstituted or methyl group, methoxy group, and t-butyl group It is selected from a phenyl group having a substituent, an unsubstituted group, or a phenoxy group having at least one substituent among a methyl group, a methoxy group, and a t-butyl group.

Considering the availability of materials and the ease of synthesis, it is preferable that R ³ and R ^{4 in} the general formula (1) are both fluorine. Specific examples of the above-mentioned pyromethene compound include the following compounds.

  The pyromethene compound of the present invention can be produced, for example, by the following method.

The compound represented by the following general formula (6) and the compound represented by the general formula (7) are heated in 1,2-dichloroethane in the presence of phosphorus oxychloride, and then represented by the following general formula (8). The compound of general formula (1) can be obtained by reacting the compound in 1,2-dichloroethane in the presence of triethylamine. Here, Ar ^{1 to} Ar ⁵ and R ^{1 to} R ⁴ are the same as described above. J represents halogen.

  The pyromethene compound represented by the general formula (1) of the present invention preferably has a decomposition temperature higher than the vacuum deposition temperature, that is, the sublimation temperature. The sublimation temperature is preferably 10 ° C. or more, more preferably 20 ° C. or more, more preferably 30 ° C. or more higher than the decomposition temperature from the viewpoint of widening the allowable range of the vacuum deposition process. When the decomposition temperature is lower than the vacuum deposition temperature, there arises a problem that modification such as decomposition or polymerization occurs during film formation. In particular, when the pyromethene compound represented by the general formula (1) is used as a dopant material, it is preferable that heat resistance is high because it is heated for a long time in a vapor deposition source as compared with a host material or the like. In addition, when melted in the vapor deposition source, it is highly possible that the sublimation property is deteriorated and the material is denatured. Therefore, the melting point is preferably high. The melting point is 200 ° C. or higher, preferably 250 ° C. or higher, more preferably 300 ° C. or higher.

  In the present invention, the pyromethene compound represented by the general formula (1) is suitably used as a light emitting device material.

  The light emitting device material of the present invention may be composed only of the pyromethene compound represented by the general formula (1), or other materials may be appropriately added for reasons such as material handling properties. .

  Next, the light emitting device of the present invention will be described in detail. The anode may be translucent in order to extract light, and the materials used are conductive metal oxides such as tin oxide, indium oxide and indium tin oxide (ITO), or gold, silver, chromium, etc. There are no particular limitations on inorganic conductive materials such as metals, copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole and polyaniline, but it is particularly desirable to use ITO glass or Nesa glass.

The resistance of the anode, which is a transparent electrode, is not limited as long as a current sufficient for light emission of the element can be supplied. For example, an ITO substrate of 300Ω / □ or less functions as an element electrode, but since it is now possible to supply a substrate of about 10Ω / □, it is particularly desirable to use a low resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of 100 to 300 nm. Further, soda lime glass, non-alkali glass or the like is used for the glass substrate, and the thickness of the glass substrate only needs to be sufficient to maintain the mechanical strength, so 0.5 mm or more is sufficient. The glass material is preferably non-alkali glass because it is better to have less ions eluted from the glass, but commercially available glass such as soda lime glass with a barrier coat such as SiO ₂ can be used. As the ITO film forming method, an electron beam method, a sputtering method, a chemical reaction method, or the like can be used, and there is no particular limitation.

  The material used for the cathode is not particularly limited as long as it is a substance that can efficiently inject electrons into the organic layer. For example, platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, Sodium, potassium, calcium, magnesium and the like can be used. Lithium, sodium, potassium, calcium, magnesium, or alloys containing these low work function metals are effective for increasing the electron injection efficiency and improving device characteristics. However, these low work function metals are generally unstable in the atmosphere. For example, the organic layer is doped with a small amount of lithium or magnesium (for example, 1 nm or less in the vacuum gauge thickness gauge display). A method using a highly stable electrode can be mentioned as a preferable example, but an inorganic salt such as lithium fluoride can also be used, and the method is not particularly limited thereto. Furthermore, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals, and inorganic materials such as silica, titania and silicon nitride, polyvinyl alcohol, Preferred examples include laminating vinyl chloride and hydrocarbon polymers. The method for producing these electrodes is not particularly limited as long as conduction can be achieved, such as resistance heating, electron beam, sputtering, ion plating, and coating.

  The light-emitting element material contained in the light-emitting element of the present invention corresponds to either a substance that emits light by itself or a substance that assists light emission, and refers to a compound that participates in light emission. Specifically, hole transport materials, light emitting materials, electron transport materials, and the like are applicable.

  The light emitting device of the present invention is formed of a layer containing a material for a light emitting device, for example, 1) hole transport layer / light emitting layer, 2) hole transport layer / light emitting layer / electron transport layer, 3) light emitting layer / Any of the electron transport layer and 4) a combination of the above-mentioned combined substances in one layer may be used. That is, as the element structure, in addition to the multilayer laminated structure of the above 1) to 3), only the light emitting material alone or a layer containing the light emitting material and the hole transport material or electron transport material may be provided as in 4).

  The hole transport layer can be formed by laminating and mixing one or more hole transport materials or a mixture of a hole transport material and a polymer binder. Examples of the hole transporting material include N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine, N, N′-dinaphthyl. -N, N'-diphenyl-4,4'-diphenyl-1,1'-diamine and other triphenylamines, bis (N-allylcarbazole) or bis (N-alkylcarbazole) s, pyrazoline derivatives, stilbene series Compounds, hydrazone compounds, oxadiazole derivatives, phthalocyanine derivatives, heterocyclic compounds typified by porphyrin derivatives, and polymer systems are preferably polycarbonates, styrene derivatives, polyvinylcarbazole, polysilane, etc. having the above monomers in the side chain. The However, there is no particular limitation as long as it is a compound that can form a thin film necessary for device fabrication, inject holes from the anode, and further transport holes.

  The light emitting layer in the present invention is formed of a light emitting material (host material, dopant material), which may be a mixture of a host material and a dopant material or a host material alone. Each of the host material and the dopant material may be one kind or a plurality of combinations. The dopant material may be included in the host material as a whole, or may be included partially. The dopant material may be either laminated or dispersed.

  The pyromethene compound of the present invention is suitably used as a light emitting material. Although it may be used as a host material, it is preferably used as a dopant material because it has a high fluorescence quantum yield and a small half-value width of an emission spectrum.

  If the doping amount is too large, a concentration quenching phenomenon occurs, so that it is preferably used in an amount of 10% by weight or less, more preferably 2% by weight or less based on the host material. As a doping method, it can be formed by a co-evaporation method with a host material, but it may be pre-mixed with the host material and then simultaneously deposited. Further, the dopant material may be included in the entire host material, or may be included partially. The dopant material may be either laminated or dispersed. Furthermore, since the pyromethene compound emits light even in a very small amount, it is also possible to use a very small amount of the pyromethene compound sandwiched between the host materials. In this case, one or more layers may be laminated with the host material. The dopant material added to the light emitting material need not be limited to only one pyromethene compound, and a plurality of pyromethene compounds may be mixed and used, or one or more kinds of known dopant materials may be mixed with a pyromethene compound. . Specifically, conventionally known rare earth complexes such as naphthalimide derivatives such as bis (diisopropylphenyl) perylenetetracarboxylic imide, perinone derivatives, 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, Quinacridone derivatives, phenoxazine derivatives, oxazine compounds, porphyrin platinum complexes, tris (2-phenylpyridyl) iridium complexes, tris {2- (2-thiophenyl) pyridyl} iridium complexes What iridium complex, etc. can coexist but not particularly limited thereto.

  The host material is not particularly limited, but has previously been known as a phosphor, fused ring derivatives such as anthracene and pyrene, metal chelated oxinoid compounds including tris (8-quinolinolato) aluminum, bisstyryl Bisstyryl derivatives such as anthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, pyrrolopyrrole derivatives , Carbazole derivatives such as 4,4′-bis (carbazolyl-N-yl) -4,4′-diphenyl and N, N′-diphenyl-3,3′-biscarbazole, N, N′-diphenyl-N, N ' Triphenylamine compounds such as di (3-methylphenyl) -4,4'-diphenyl-1,1'-diamine, indole derivatives, azole derivatives such as triazole, oxadiazole, imidazole, phenanthroline derivatives, quinoline derivatives, naphthyridine In the polymer system, polyphenylene vinylene such as derivatives, oligopyridine derivatives such as bipyridine and terpyridine, iridium complexes such as porphyrin platinum complex, tris (2-phenylpyridyl) iridium complex, and tris {2- (2-thiophenyl) pyridyl} iridium complex Derivatives, polyparaphenylene derivatives, polythiophene derivatives and the like can be used.

  As the electron transporting material in the present invention, it is necessary to efficiently transport electrons from the cathode between 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, excellent stability, and a substance that does not easily generate trapping impurities during manufacturing and use. As substances satisfying such conditions, quinolinol derivative compounds represented by 8-hydroxyquinoline aluminum, tropolone compounds, flavonol compounds, perylene derivatives, perinone derivatives, naphthalene derivatives, coumarin derivatives, oxadiazole derivatives, aldazine derivatives, bisstyryl derivatives , Pyrazine derivatives, phenanthroline derivatives, quinoline derivatives, aromatic phosphorus oxide compounds and the like, but are not particularly limited. These electron transport materials are used alone, but may be laminated or mixed with different electron transport materials.

  The hole blocking layer is a layer for preventing the holes from the anode from moving between the electrodes to which an electric field is applied without recombining with the electrons from the cathode, and the kind of material constituting each layer. Depending on the case, insertion of this layer may increase the probability of recombination of holes and electrons, and may improve the light emission efficiency. Therefore, it is desirable that the hole-occluding material has a lower maximum occupied molecular orbital level than the hole-transporting material in terms of energy, and it is difficult to generate an exciplex with the material constituting the adjacent layer. A compound that can efficiently block the movement of holes from the anode is preferable, and a material having a high electron transporting capability also has a high hole blocking capability. Therefore, the electron transporting material is a preferable example.

  The above hole transport layer, light-emitting layer, electron transport layer, and hole blocking layer may be a single material or a laminate of two or more materials, mixed, or a polymer binder such as polyvinyl chloride, polycarbonate, polystyrene, poly (N -Vinylcarbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, etc. It can also be used by being dispersed in a soluble resin, a curable resin such as a phenol resin, a xylene resin, a petroleum resin, a urea resin, a melamine resin, an unsaturated polyester resin, an alkyd resin, an epoxy resin, or a silicone resin.

  The thin film forming method of the light emitting material is not particularly limited, such as resistance heating vacuum deposition, electron beam vacuum deposition, sputtering, molecular lamination method, coating method, etc., but resistance heating vacuum deposition and electron beam vacuum deposition are usually characteristics. In terms of surface. The thickness of the layer depends on the resistance value of the light emitting material and cannot be limited, but is selected from 1 to 1000 nm.

  Electrical energy mainly refers to direct current, but pulsed current or alternating current can also be used. The current value and the voltage value are not particularly limited, but the maximum luminance should be obtained with the lowest possible energy in consideration of the power consumption and lifetime of the element.

  The matrix in the present invention refers to a matrix in which pixels for display are arranged in a lattice pattern, and displays characters and images by a set of pixels. The shape and size of the pixel are determined by the application. For example, a rectangular pixel with a side of 300 μm or less is normally used for displaying images and characters on a personal computer, monitor, television, etc. In a large display such as a display panel, a pixel with a side of mm order is used. . In monochrome display, pixels of the same color may be arranged. However, in color display, 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 driving method may be either a line sequential driving method or an active matrix. The line-sequential driving has an advantage that the structure is simple. However, the active matrix may be superior in consideration of the operation characteristics, so that it is necessary to properly use it depending on the application.

  The segment type in the present invention means that a pattern is formed so as to display predetermined information, and a predetermined region is caused to emit light. For example, the time and temperature display in a digital clock or a thermometer, the operation status display of an audio device or an electromagnetic cooker, the panel display of an automobile, etc. The matrix display and the segment display may coexist in the same panel.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited by these examples. In addition, the number of the compound in each following Example points out the number of the compound described above. The evaluation method for structural analysis is shown below.

¹ H-NMR was measured with a deuterated chloroform solution using superconducting FTNMR EX-270 (manufactured by JEOL Ltd.).

  Elemental analysis is performed using a CHN coder MT-3 type (manufactured by Yanagimoto Seisakusho Co., Ltd.), ion chromatography DX320 (manufactured by Nippon Dionex Co., Ltd.) and a sequential ICP emission spectroscopic analyzer SPS4000 (manufactured by Seiko Instruments Inc.). And measured.

  Mass spectrum was measured using JMS-DX303 (manufactured by JEOL Ltd.).

  The melting point was measured with a differential scanning calorimeter (DSC-50 manufactured by Shimadzu Corporation) in a nitrogen atmosphere at a heating rate of 2 ° C./min.

  For the fluorescence spectrum, an F-2500 type fluorescence spectrophotometer (manufactured by Hitachi, Ltd.) was used.

  The luminance was measured using a luminance meter (Topcon, BM-8) under the conditions of a viewing angle of 0.2 degrees and a response of 1 ms.

The luminance half time was measured as follows as an index of element lifetime. Light was emitted at a constant current of 4 mA / cm ² , and then the time when the light emission luminance was reduced by half was measured.

The temperature of the vapor deposition source was increased by 10 ° C. at a degree of vacuum of 1 × 10 ⁻⁴ Pa or less, and the temperature of the vapor deposition source when the deposition rate of the vapor deposition film reached 0.1 nm / second or more was defined as the sublimation temperature. The vapor deposition source used was an aluminum nitride crucible having a cylindrical shape and a capacity of 10 cc. There was a thermocouple at the bottom of the crucible, and the temperature at the bottom of the crucible was measured.

  In the decomposition test of the pyromethene compound, it was judged that heating was performed in the above sublimation temperature under a nitrogen atmosphere for 24 hours, and the HPLC purity change before and after heating was decomposed by 1% or more. That is, the material not decomposed by this measurement has a decomposition temperature higher than the sublimation temperature.

  HPLC measurement was performed using CLASS-VP manufactured by Shimadzu Corporation, the flow rate was 1.0 ml / min, the column was Mightysil RP-8GP manufactured by Kanto Chemical Co., Ltd., the column temperature was 45 ° C., and the analysis was performed at 254 nm. .

  The materials used in the following examples and comparative examples are shown below.

Example 1
Synthesis method of compound [3] In 30 ml of 1,2-dichloroethane, 4.1 g (0.01 mol) of 2- (4-tert-butylbenzoyl) -3,5-bis (4-methylphenyl) pyrrole, 2 , 4-bis (4-methylphenyl) pyrrole (2.5 g, 0.01 mol) and phosphorus oxychloride (1.5 g) were added and reacted for 12 hours under heating and reflux. After cooling to room temperature, 5.2 g of diisopropylethylamine and 5.6 g of boron trifluoride diethyl ether complex were added and stirred for 6 hours. 50 ml of water was added, dichloromethane was added, the organic layer was extracted, concentrated, purified by column chromatography using silica gel, and further purified by sublimation to obtain 4.3 g of reddish purple powder. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.07 (s, 9H), 2.13 (s, 6H), 2.39 (s, 6H), 6.47 (t, 4H), 6.63 (s, 8H), 6.75 (d, 2H), 7.23 (d, 4H), 7.80 (d, 4H)
The results of elemental analysis were as follows as the composition formula C ₄₇ H ₄₃ BF ₂ N ₂ . The values in parentheses are theoretical values. C: 82.3% (82.5%), H: 6.3% (6.3%), B: 1.6% (1.6%), F: 6.3% (5.6%) ), N: 4.2% (4.1%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 684. From the above, it was confirmed that the reddish purple powder as the product was the compound [3]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Example 2
Synthesis method of compound [4] 4.1 g (0.01 mol) of 2- (2,6-dimethoxybenzoyl) -3,5-bis (4-methylphenyl) pyrrole, 2,4-bis (4-methylphenyl) ) 2.5 g of pyrrole was synthesized in the same manner as compound [3]. 0.7 g of reddish purple powder was obtained. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 2.14 (s, 6H), 2.37 (s, 6H), 3.50 (s, 6H), 5.61 (d, 2H), 6.35 (s, 2H), 6.35 (t, 1H), 6.55 (q, 8H), 7.22 (d, 4H), 7.82 (d, 4H)
Elemental analysis results were as follows as the composition formula _{C 45 H 39 BF 2 N 2} O 2. The values in parentheses are theoretical values. C: 78.6% (78.5%), H: 5.7% (5.7%), B: 1.6% (1.6%), F: 5.4% (5.5%) ), N: 4.2% (4.1%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 687. From the above, it was confirmed that the reddish purple powder as the product was the compound [4]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Example 3
Method of synthesizing compound [24] Using 4.4 g of 2-benzoyl-3,5-bis (4-t-butylphenyl) pyrrole and 3.3 g of 2,4-bis (4-t-butylphenyl) pyrrole, compound Synthesized as in [3]. 4.4 g of red powder was obtained. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.18 (s, 18H), 1.35 (s, 18H), 6.40 (t, 2H), 6.53-6.66 (m, 7H), 6.77-6.84 (m, 6H), 7.46 (d, 4H), 7.86 (d, 4H)
The results of elemental analysis were as follows as the composition formula C ₅₅ H ₅₉ BF ₂ N ₂ . The values in parentheses are theoretical values. C: 83.1% (82.9%), H: 7.7% (7.5%), B: 1.3% (1.4%), F: 4.3% (4.8%) ), N: 3.5% (3.5%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 796. From the above, it was confirmed that the red powder as the product was the compound [24]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Example 4
2. Synthesis method of compound [25] 4.5 g of 2- (4-methylbenzoyl) -3,5-bis (4-tert-butylphenyl) pyrrole, 2,4-bis (4-tert-butylphenyl) pyrrole Using 3 g, the compound was synthesized in the same manner as Compound [3]. 4 g of red powder was obtained. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.20 (s, 18H), 1.35 (s, 18H), 1.94 (s, 3H), 6.22 (d, 2H), 6.52 (s, 2H), 6.68 (q, 6H), 6.86 (d, 4H), 7.45 (d, 4H), 7.85 (d, 4H)
The results of elemental analysis were as follows as the composition formula C ₅₆ H ₆₁ BF ₂ N ₂ . The values in parentheses are theoretical values. C: 83.2% (82.9%), H: 7.6% (7.6%), B: 1.3% (1.33%), F: 4.0% (4.7%) ), N: 3.6% (3.5%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 810. From the above, it was confirmed that the red powder as the product was the compound [25]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Example 5
2. Synthesis method of compound [26] 2- (4-methoxybenzoyl) -3,5-bis (4-t-butylphenyl) pyrrole 4.7 g, 2,4-bis (4-t-butylphenyl) pyrrole Using 3 g, the compound was synthesized in the same manner as Compound [3]. 5 g of red powder was obtained. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.20 (s, 18H), 1.35 (s, 18H), 3.51 (s, 3H), 5.94 (d, 2H), 6.54 (s, 2H), 6.69 (t, 6H), 6.89 (d, 4H), 7.45 (d, 4H), 7.85 (d, 4H)
Elemental analysis results were as follows as the composition formula _{C 56 H 61 BF 2 N 2} O. The values in parentheses are theoretical values. C: 81.3% (81.3%), H: 7.5% (7.4%), B: 1.3% (1.3%), F: 5.3% (4.6%) ), N: 3.4% (3.4%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 826. From the above, it was confirmed that the red powder as the product was the compound [26]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Example 6
Synthesis Method of Compound [29] 2- (2,6-Dimethoxybenzoyl) -3,5-bis (4-tert-butylphenyl) pyrrole 5.0 g, 2,4-bis (4-tert-butylphenyl) pyrrole Synthesis was performed in the same manner as Compound [3] using 3.3 g. 0.3 g of reddish purple powder was obtained. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.20 (s, 18H), 1.35 (s, 18H), 3.50 (s, 6H), 5.56 (d, 2H), 6.40-6.48 (m, 3H) , 6.72 (d, 4H), 6.85 (d, 4H), 7.43 (d, 4H), 7.87 (d, 4H)
The results of elemental analysis were as follows as the composition formula C ₅₇ H ₆₃ BF ₂ N ₂ O ₂ . The values in parentheses are theoretical values. C: 79.9% (79.9%), H: 7.5% (7.4%), B: 1.2% (1.3%), F: 4.0% (4.4%) ), N: 3.4% (3.3%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 856. From the above, it was confirmed that the reddish purple powder as the product was the compound [29]. The decomposition test results, melting point and sublimation temperature of the pyromethene compound are shown in Table 1.

Comparative Example 1
Table 1 shows the decomposition test results, melting point and sublimation temperature of the DPT1 pyromethene compound shown below, which is a dopant material.

Comparative Example 2
Table 1 shows the decomposition test results, melting point, and sublimation temperature of the DPT2 pyromethene compound shown below, which is a dopant material.

Example 7
A light emitting device using the compound [3] was produced as follows. 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 evaporated product) was cut into 30 × 40 mm and etched. The obtained substrate was ultrasonically washed with acetone and “Semicocrine 56” for 15 minutes, respectively, and then washed with ultrapure water. Subsequently, it was ultrasonically cleaned with isopropyl alcohol for 15 minutes and then immersed in hot methanol for 15 minutes to dry. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁵ Pa or less. First, copper phthalocyanine (CuPc) was deposited as a hole injecting material by a resistance heating method to a thickness of 10 nm. Next, 50 nm of N, N′-dinaphthyl-N, N′-diphenyl-4,4′-diphenyl-1,1′-diamine (HTL1) was deposited as a hole transport material. Next, using the HST1 as a host material and the compound [3] as a dopant material, co-evaporated to a thickness of 40 nm so that the dopant concentration becomes 1 wt%, and the ETL1 was laminated to a thickness of 35 nm as an electron transport material. did. Next, as an electron injection material, lithium was deposited to 0.5 nm and silver was deposited to 150 nm to form a cathode, and a 5 × 5 mm square device was produced. The film thickness referred to here is a display value of a crystal oscillation type film thickness monitor. When an electric current was passed through the light emitting element at 10 mA / cm ² , the emission spectrum showed red light emission with a peak wavelength of 610 nm and a light emission efficiency of 4.8 cd / A. This device did not reach half the luminance even after 1000 hours.

Examples 8-26, Comparative Examples 3-5
A light emitting device was manufactured in the same manner as in Example 7 except that the materials shown in Table 2 were used as the hole injection material, the hole transport material, the host material, the dopant material, the electron transport material, and the electron injection material. The results are shown in Tables 2 and 3.

Example 27
A light emitting device was fabricated in the same manner as in Example 7 except that the host material was HST9 and the dopant material was compound [24]. When an electric current was passed through the light-emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 617 nm and a light emission efficiency of 5.2 cd / A was obtained.

Example 28
A light emitting device was fabricated in the same manner as in Example 7, except that the host material was HST10, the dopant material was Compound [25], and the electron transport material was ETL9. When an electric current was passed through the light-emitting element at 10 mA / cm ² , red light emission having a peak wavelength of 614 nm and a light emission efficiency of 5.5 cd / A was obtained.

Example 29
A light emitting device was fabricated in the same manner as in Example 7 except that the host material was HST11 and the dopant material was compound [4]. When an electric current was passed through the light-emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 616 nm and a light emission efficiency of 4.0 cd / A was obtained.

Example 30
A light emitting device was fabricated in the same manner as in Example 7 except that the hole transport material was HTL3. When an electric current was passed through the light-emitting element at 10 mA / cm ² , red light emission having a peak wavelength of 610 nm and a light emission efficiency of 5.7 cd / A was obtained.

Example 31
A light emitting device was fabricated in the same manner as in Example 7 except that the hole transport material was HTL4. When an electric current was passed through the light emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 609 nm and a light emission efficiency of 5.4 cd / A was obtained.

Example 32
A light emitting device was manufactured in the same manner as in Example 7 except that the electron transport material was ETL2 and the electron injection material was lithium oxide. When an electric current was passed through the light-emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 610 nm and a light emission efficiency of 5.5 cd / A was obtained.

Example 33
The light emitting device was manufactured in the same manner as in Example 7 until the hole transporting material was deposited to 50 nm, and then HST3 was used as the host material and compound [24] was used as the dopant material, so that the dopant concentration was 1 wt%. HST3 was vapor-deposited to a thickness of 10 nm as an electron transport material, and ETL4 was laminated to a thickness of 15 nm as an electron-transport material. Next, as an electron injection material, lithium was deposited to 0.5 nm and silver was deposited to 150 nm to form a cathode, and a 5 × 5 mm square device was produced. When an electric current was passed through the light emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 617 nm and a light emission efficiency of 6.2 cd / A was obtained.

Example 34
A light emitting device was manufactured in the same manner as in Example 7 except that the host material [3] and the dopant material were not used. When an electric current was passed through the light-emitting element at 10 mA / cm ² , a red light emission spectrum with a peak wavelength of 615 nm and a light emission efficiency of 1.5 cd / A was obtained.

Example 35
The light emitting device is manufactured in the same manner as in Example 7 until the hole transport material is deposited to 50 nm, and then HST3 is used as the host material and the compound [26] is used as the dopant material, so that the dopant concentration becomes 1 wt%. Further, using HST12 shown below as a host material and DPT3 shown below as a dopant material, the material is co-evaporated to a thickness of 15 nm so that the dopant concentration is 2 wt%. As a result, ETL1 was laminated to a thickness of 35 nm. Next, as an electron injection material, lithium was deposited to 0.5 nm and silver was deposited to 150 nm to form a cathode, and a 5 × 5 mm square device was produced. When a current was passed through the light emitting element at 10 mA / cm ² , white light emission with a light emission efficiency of 7.0 cd / A was obtained.

Example 36
Synthesis method of compound [51] In 20 ml of 1,2-dichloroethane, 2.0 g (0.047 mol) of 2-benzoyl-3,5-bis (4-tert-butylphenyl) pyrrole, 2,4-bis ( 4-Methoxyphenyl) pyrrole (2.5 g, 0.047 mol) and phosphorus oxychloride (0.72 g) were added, and the mixture was allowed to react for 12 hours under heating and reflux. After cooling to room temperature, 4.8 g of diisopropylethylamine and 5.3 g of boron trifluoride diethyl ether complex were added and stirred for 6 hours. After adding 20 ml of water and adding dichloromethane, the organic layer was extracted, concentrated, purified by column chromatography using silica gel, and further purified by sublimation to obtain 1.9 g of red powder. The results of ¹ H-NMR analysis of the obtained powder were as follows.
¹ H-NMR (CDCl ₃ (d = ppm)): 1.19 (s, 9H), 1.35 (s, 9H), 3.66 (s, 3H), 3.85 (s, 3H), 6.36 (d, 2H), 6.44 -6.52 (dd, 4H), 6.62-6.68 (m, 5H), 6.80-6.86 (m, 4H), 6.97 (d, 2H), 7.45 (d, 2H), 7.83-7.92 (dd, 4H)
The results of elemental analysis were as follows as the composition formula C ₄₉ H ₄₇ O ₂ BF ₂ N ₂ . The values in parentheses are theoretical values. C: 79.3% (79.0%), H: 6.4% (6.3%), O: 4.4% (4.3%), B: 1.4% (1.5%) ), F: 4.3% (5.1%), N: 3.9% (3.8%).

  From the mass spectrum, the main molecular ion peak of the target product was m / Z = 744. From the above, it was confirmed that the red powder as the product was the compound [51].

Next, a light emitting device was produced in the same manner as in Example 7 except that the compound [51] was used as the dopant material. When this light emitting device was driven at 10 mA / cm ² , red light emission with a peak wavelength of the emission spectrum of 627 nm and a light emission efficiency of 4.2 cd / A was obtained. This device did not reach half the luminance even after 1000 hours.

  Compound [51] had a sublimation temperature of 260 ° C. and did not decompose at the sublimation temperature.

Comparative Example 6
A glass substrate with ITO is placed in a vacuum deposition apparatus, and the process is performed in the same manner as in Example 7 until the degree of vacuum in the apparatus is reduced to 5 × 10 ⁻⁵ Pa or less. As a hole transport material, 4,4′-bis (N- (m-tolyl) -N-phenylamino) biphenyl (m-MTDATA) was deposited by 50 nm. Next, HST1 was used as the host material and compound DPT2 was used as the dopant material, so that the host material was co-evaporated to a thickness of 15 nm so that the dopant concentration was 1 wt%, and the host material was laminated to a thickness of 35 nm. Next, lithium was deposited to 0.5 nm and silver was deposited to 150 nm to prepare a cathode having a 5 × 5 mm square. The light emission spectrum from this light emitting element was red light emission with a peak wavelength of 618 nm and a light emission efficiency of 4.2 cd / A. The luminance half time was 200 hours.

  From Tables 1 to 3, by using the pyromethene compound of the present invention, a red light emitting device with higher luminous efficiency and longer life than before was obtained without any modification such as decomposition or polymerization during vacuum deposition.

Claims (5)

A pyromethene compound represented by the general formula (1) .

^(R 1 to R ² are hydrogen ^.R 3 to R ⁴ is .A r ⁵ is the following formula ^.Ar 1 ~ Ar ⁴ is a fluorine para-position represents a phenyl group substituted with a methyl group (3 ).

(R ¹¹ and R ¹³ are hydrogen. R ¹² is selected from hydrogen, methyl group, methoxy group, and t-butyl group. R ¹⁰ and R ¹⁴ may be the same or different, Although selected from methoxy ^{group, when R 10} and ^{R 14} is hydrogen at the same time, ^{R 12} is a methyl group, a methoxy group, selected et or t- butyl group.)) A pyromethene compound represented by the general formula (1) .

^(R 1 to R ² are hydrogen ^.R 3 to R ⁴ is .A r ⁵ is the following general formula ^.Ar 1 ~ Ar ⁴ is a fluorine represents a phenyl group para substituted with t- butyl group It is represented by (4).

(R ¹⁶ and R ¹⁸ are hydrogen. R ¹⁷ is selected from hydrogen, a methyl group, a methoxy group, and a t-butyl group. R ¹⁵ and R ¹⁹ may be the same or different. well, hydrogen is chosen et or methoxy group.)) A light-emitting element material using the pyromethene compound according to claim 1. A light emitting device comprising at least a light emitting layer between an anode and a cathode and emitting light by electric energy, wherein the light emitting device comprises the light emitting device material according to claim 3. The light emitting device according to claim 4, wherein the light emitting device material is a dopant material.