JP4595346B2 - Light emitting device material and light emitting device including the same - Google Patents

Description

  The present invention is an element that can convert electrical energy into light, and can be used in the fields of display elements, flat panel displays, backlights, lighting, interiors, signs, signboards, electrophotographic machines, optical signal generators, and the like. The present invention relates to an element and a material for a light emitting element.

  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 C.D. W. Since Tang et al. Have shown that organic multilayer thin-film elements emit light with high brightness, many research institutions have studied.

With the aim of realizing a full-color display, light emitting materials are required to have three primary colors (RGB), so far green light emitting materials have been studied most, followed by blue light emitting materials, and most recently red light emitting materials. Improvement is desired and earnest research has been done. As a light emitting material, not only a fluorescent material but also a phosphorescent material has been studied. In addition, as a charge transport material, research on a hole transport material has been active so far, but recently, an electron transport material has been eagerly studied (see, for example, Patent Document 1 and Patent Document 2).
JP 2000-119644 A (page 17) International Publication No. 00/03565 Pamphlet (Claims)

  However, many of the light emitting materials, hole transport materials, and electron transport materials that are conventionally used have poor durability. This is because crystallization occurs due to heat generated from the element due to energization for a long time, and the element life is shortened. On the other hand, materials imparted with amorphous properties to suppress this crystallization often have degradation such as decomposition and polymerization during vacuum deposition because of their low sublimation properties.

  In addition, many light-emitting elements using conventional materials have a high driving voltage, and a high voltage must be applied to obtain a desired luminance. It was.

  An object of the present invention is to solve such problems of the prior art and to provide a light emitting device having a low driving voltage and excellent durability.

  That is, the present invention is an element in which at least a light emitting layer and an electron transport layer are sequentially laminated between an anode and a cathode and emits light by electric energy, and the electron transport layer is represented by the general formula (1). It is a light emitting element containing.

(Here, A is a substituent having a 1,10-phenanthroline skeleton. B is represented by at least one selected from a benzene ring, a terphenyl skeleton, and a naphthalene ring, provided that B is a benzene ring. When all A include an alkyl group and / or an aryl group in the skeleton, n is 2. Also, all 1,10-phenanthroline skeletons are bonded to B at the 2-position, provided that Excluding the compound represented by formula (2).

(Where L ₁ , Y ₂₃ ~ Y ₂₉ And Y ₃₃ ~ Y ₃₉ The combination is any one of [1] to [48] below. )

  The present invention can provide a light-emitting element with low driving voltage and excellent durability.

  The present invention is an element in which at least a light emitting layer and an electron transport layer are sequentially laminated between an anode and a cathode and emits light by electric energy, and the electron transport layer is represented by the following general formula (1). including.

Here, A is a substituent having a 1,10-phenanthroline skeleton. B is represented by at least one selected from a benzene ring, a terphenyl skeleton, and a naphthalene ring. However, when B is a benzene ring, all A include an alkyl group and / or an aryl group in the skeleton. n is 2. All 1,10-phenanthroline skeletons are bonded to B at the 2-position. However, the compound represented by the following formula (2) is excluded.

(Where L ₁ , Y ₂₃ ~ Y ₂₉ And Y ₃₃ ~ Y ₃₉ The combination is any one of [1] to [48] below. )

  Here, the terphenyl skeleton is a group in which three benzene rings are connected, and these benzene rings may be connected at any position. The alkyl group represents a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, or a butyl group, and the aryl group represents, for example, a phenyl group, a tolyl group, a biphenyl group, a naphthyl group, a phenanthryl group, an anthryl group. An aromatic hydrocarbon group such as a group is shown. A may be the same or different. When B is a benzene ring, the plurality of A bonded to B all contain an alkyl group and / or an aryl group.

  In order to keep the driving voltage of the light emitting element low, it is desirable that the material has high carrier mobility. Therefore, a substituent having a 1,10-phenanthroline skeleton is more preferably used as A in the general formula (1). In addition, if the molecular weight of the material is too large, the sublimation property is lowered, and the probability of thermal decomposition during vacuum deposition increases. On the other hand, if the molecular weight of the material is too small, the thin film forming ability is often poor. Therefore, n in the general formula (1) is 2.

  When B in the general formula (1) is a benzene ring, this B is preferably a 1,4-phenylene group or a 1,3-phenylene group for ease of synthesis. In this case, all A are from the viewpoint of heat resistance. It preferably has an aryl group. As the aryl group, unsubstituted or substituted phenyl group, p-tolyl group, m-tolyl group, 3,5-dimethylphenyl group, 4-t-butylphenyl group, etc. from the viewpoint of ease of synthesis and sublimation An unsubstituted or substituted naphthyl group such as a substituted phenyl group, a 1-naphthyl group, a 2-naphthyl group, and a 2-methyl-1-naphthyl group is more preferable.

  Further, when B in the general formula (1) is a naphthalene ring, this B is a 1,6-naphthylene group, 1,7-naphthylene group, 2,6-naphthylene group, 2,7-naphthylene for ease of synthesis. Groups are more preferred. Further, when B in the general formula (1) is a substituent having a terphenyl skeleton, this B is more preferably a terphenyl group in which at least one benzene ring is connected at the ortho position from the viewpoint of sublimation. preferable.

  The light emitting device material represented by the general formula (1) can be synthesized by the following method, but is not particularly limited.

  As a method for obtaining a light emitting device material represented by the general formula (1), a reactive substituent is introduced into a compound corresponding to B in the general formula (1), and then converted to A in the general formula (1). The method is preferred. Examples of the reactive substituent include, but are not particularly limited to, an acetyl group, an iodo group, and a bromo group.

  An example of the method for introducing an acetyl group is acylation of Friedel-Crafts. Examples of references include “Example A. Starting compound (f) 2,2′-diacetyl-9,9′-spirobifluorene” on page 27 of JP-A-7-278537, Helvetica Chimica Acta, vol. 52 (1969), page 1210, "Experimenteller Tell 2,2'-diacetyl-9, 9'-spirobifluorene (IV)". Specifically, a compound corresponding to B in the general formula (1) can be reacted with acetyl chloride and aluminum chloride in 1,2-dichloroethane at 50 ° C. and treated in a conventional manner to introduce an acetyl group. . By changing the equivalent of acetyl chloride and aluminum chloride, 1 to 4 substituents can be obtained.

  As another method, a method of converting a trifluoromethanesulfonyloxy group into an acetyl group with a palladium catalyst can be used. References include J.A. Org. Chem. vol. 57 (1992), page 1481. Specifically, a compound corresponding to B of the general formula (1) having a trifluoromethanesulfonyloxy group is reacted with butyl vinyl ether at 50 to 120 ° C. in a dimethylformamide and triethylamine under a palladium catalyst at a conventional method. Then, an acetyl group can be introduced. In this method, an acetyl group can also be introduced by using a bromo group or an iodo group in place of the trifluoromethanesulfonyloxy group.

  For introduction of an iodo group, Tetrahedron Letters, vol. 38 (1997), page 1487, and the like. Specifically, a compound corresponding to B in the general formula (1) is reacted with iodine and bis (trifluoroacetoxy) iodobenzene at 50 ° C. to 60 ° C. in carbon tetrachloride, treated in a conventional manner, and an iodo group Can be introduced.

  For the introduction of bromo group, see Angew. Chem. Int. Ed. Engl. 25 (1986) No. 25. 12 page 1098 and the like. Specifically, a compound corresponding to B in the general formula (1) can be reacted with bromine at room temperature and treated in a conventional manner to introduce a bromo group. By changing the equivalent of bromine, 1 to 4 substituents can be obtained.

  For a method for converting the reactive substituent to A in the general formula (1), Tetrahedron Letters, vol. 40 (1999). Page 7312 scheme and J.P. Org. Chem. 1996, 61. Page 3020 “2-Phenyl-1,10-phenanthroline”, Tetrahedron Letters, vol. 23 (1982). Page 5291 to page 5294. Specifically, the acetyl form of the compound corresponding to B in the general formula (1) is 8-amino-7 at 50 ° C. to reflux temperature in a lower alcohol such as ethanol or isopropyl alcohol or dioxane in the presence of potassium hydroxide. A method of reacting with quinoline carbaldehyde or 1-amino-2-naphthalene carbaldehyde and treating in a conventional manner, or an iodo or bromo form of a compound corresponding to B in the general formula (1) in a solvent such as toluene or THF Lithiation with metal lithium, alkyllithium such as t-butyllithium and n-butyllithium at −100 ° C. to 50 ° C., followed by reaction with phenanthrolines or benzo [h] quinolines at −20 to 60 ° C. After treatment by the method, the resulting compound is converted to manganese dioxide, nitrobenzene, chloranil, DDQ, air, oxygen, water In a method of treatment with etc., it can be introduced 1,10-phenanthroline skeleton or benzo [h] quinoline skeleton.

  When the skeleton of A in the general formula (1) contains an alkyl group and / or an aryl group, the compound having the skeleton of the general formula (1) is -20 to 60 ° C in a solvent such as toluene or THF, The compound obtained after reacting with alkyllithium or aryllithium which is a lithiated product of alkyl group or aryl group introduced here, or alkylmagnesium halide or arylmagnesium halide which is a Grineer reagent and treating in a conventional manner Is treated with manganese dioxide, nitrobenzene, chloranil, DDQ, air, oxygen, water or the like, whereby an alkyl group or an aryl group can be introduced into the skeleton of A. The above alkyl lithium and aryl lithium can be obtained by reacting alkyl lithium such as metal lithium or n-butyl lithium with the corresponding alkyl halide or aryl halide. Alkyl magnesium halide or aryl magnesium halide can be obtained. It can be obtained by reacting magnesium metal with alkyl halide or aryl halide.

  The compound of the general formula (1) can be purified by purification methods such as column chromatography, recrystallization, sublimation alone or in combination. In column chromatography, it can be purified using silica gel, alumina, florisil or the like as a filler. In recrystallization, toluene, hexane, tetrahydrofuran, dioxane, dimethoxyethane, ethanol, methanol, acetone, methyl ethyl ketone, ethyl acetate, n-butyrolactone, nitrobenzene, dichloromethane, chloroform, dimethyl sulfoxide, dimethylformamide, 1-methyl-2-pyrrolidone, It can be purified by using commonly used solvents such as 1,3-dimethyl-2-imidazolidinone, pyridine, triethylamine, alone or in combination.

  Specific examples of the light emitting device material include the following structures, but are not particularly limited.

  Moreover, this invention is a light emitting element containing the material for light emitting elements represented by the said General formula (1).

In the light emitting device of the present invention, if the anode is transparent for extracting light, a conductive metal oxide such as tin oxide, indium oxide, indium tin oxide (ITO), or a metal such as gold, silver, or chromium, or iodide Inorganic conductive materials such as copper and copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline are not particularly limited, but it is particularly desirable 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. For example, an ITO substrate of 300 Ω / □ or less functions as an element electrode. However, since it is now possible to supply a substrate of about 10 Ω / □, 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. Regarding the material of the glass, non-alkali glass is preferred because it is better that ions eluted from the glass are less. However, soda lime glass having a barrier coat such as SiO ₂ is also commercially available and can be used. The ITO film forming method is not particularly limited, such as an electron beam method, a sputtering method, or a chemical reaction method.

  In the light emitting device of the present invention, the cathode is not particularly limited as long as it can efficiently inject electrons into the organic layer, but generally platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium , Sodium, potassium, calcium, magnesium, etc., but 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, cesium, or magnesium (1 nm or less in the thickness gauge display of vacuum deposition). 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, indium, or alloys using these metals, and inorganic substances such as silica, titania, silicon nitride, polyvinyl alcohol, vinyl chloride, Preferred examples include laminating 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.

  In the light emitting device of the present invention, the light emitting substance is 1) hole transport layer / light emitting layer, 2) hole transport layer / light emitting layer / electron transport layer, 3) light emitting layer / electron transport layer, and 4) Any of the mixed substances may be mixed. 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). Furthermore, the light-emitting substance in the light-emitting element of the present invention corresponds to both a substance that emits light by itself and a substance that assists the light emission, and refers to a compound, a layer, and the like that are involved in light emission.

  In the light emitting device of the present invention, the hole transporting material is required to efficiently transport holes from the anode between electrodes to which an electric field is applied, and the hole injection efficiency is high. It is desirable to transport well. For this purpose, it is required that the ionization potential is low, the hole mobility is high, the stability is high, and the trapping impurities are difficult to be generated during production and use.

  N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine, N, N′-dinaphthyl, and the like satisfying such conditions -Triphenylamines such as -N, N'-diphenyl-4,4'-diphenyl-1,1'-diamine, carbazoles such as bis (N-allylcarbazole) and bis (N-alkylcarbazole), Indole derivatives, pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives, phthalocyanine derivatives, heterocyclic compounds typified by porphyrin derivatives, in the case of polymers, polycarbonates or styrene derivatives having the above-mentioned side chains, polyvinyl Examples thereof include carbazole and polysilane.

  The light emitting material in the present invention may be either a host material alone or a combination of a host material and a dopant material. 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.

  The light-emitting material used in the light-emitting element of the present invention needs to efficiently recombine holes received from the hole transport layer or the direct anode and electrons received from the electron transport layer or the direct cathode.

  The material for the light-emitting element of the present invention is preferable as a substance satisfying such conditions, but other condensed ring derivatives such as anthracene, phenanthrene, pyrene, perylene, chrysene, etc., which are known as light emitters, tris (8-quinolinolato) Metal complexes of quinolinol derivatives such as aluminum, benzoxazole derivatives, stilbene derivatives, benzthiazole derivatives, thiadiazole derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, oxadiazole derivatives, bisstyrylanthracene derivatives and distyrylbenzene Bisstyryl derivatives such as derivatives, metal complexes combining quinolinol derivatives with different ligands, oxadiazole derivative metal complexes, benzazole derivative metal complexes, coumarin derivatives, Ropirijin derivatives, pyrrolopyrrole derivatives, silole derivatives, perinone derivatives, thiadiazolopyridine derivatives, the polymer system, polyphenylene vinylene derivatives, polyparaphenylene derivatives, and polythiophene derivatives.

  When a dopant material is included, the dopant material added to the light-emitting material needs to efficiently receive recombination energy from the host material, and it is desirable that the quantum yield is high and concentration quenching is difficult to occur. Furthermore, it is required to be a substance that is excellent in stability and is unlikely to generate trapping impurities during manufacturing and use.

  The material for the light emitting device of the present invention is preferable as a substance satisfying such conditions, but in addition, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopylene, dibenzopyrene, rubrene, and benzoxazole derivatives , Benzthiazole derivatives, benzimidazole derivatives, benztriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives , Bisstyryl derivatives such as bisstyryl anthracene derivatives and distyrylbenzene derivatives, diazaindacene derivatives, furan derivatives Benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di (2-methylphenyl) isobenzofuran, di (2-trifluoromethylphenyl) isobenzofuran, isobenzofuran derivatives such as phenylisobenzofuran, dibenzofuran derivatives, 7-dialkyl Aminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzthiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives, 3-benzoxa Coumarin derivatives such as zolyl coumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, Nthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, Examples include pyromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, diazaflavin derivatives, and the like.

  As the dopant material, not only the fluorescent (singlet light emission) material but also a phosphorescent (triplet light emission) material is preferably used. Specifically, porphyrin platinum complex, tris (2-phenylpyridyl) iridium complex, tris {2- (2-thiophenyl) pyridyl} iridium complex, tris {2- (2-benzothiophenyl) pyridyl} iridium complex, tris (2-phenylbenzothiazole) iridium complex, tris (2-phenylbenzoxazole) iridium complex, trisbenzoquinoline iridium complex, bis (2-phenylpyridyl) (acetylacetonato) iridium complex, bis {2- (2-thiophenyl) ) Pyridyl} iridium complex, bis {2- (2-benzothiophenyl) pyridyl} (acetylacetonato) iridium complex, bis (2-phenylbenzothiazole) (acetylacetonato) iridium complex, bis (2-phenylbenzooxa) Z Le) (acetylacetonato) iridium complex, bis benzoquinoline (acetylacetonate) iridium, etc. complex.

  The electron transporting material used in the light-emitting device of the present invention needs to efficiently transport electrons from the cathode between electrodes to which an electric field is applied, has high electron injection efficiency, and transports injected electrons efficiently. It is desirable to do. 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. On the other hand, considering the recombination balance between holes and electrons, a material with a high ability to efficiently prevent holes from the anode from flowing to the cathode side without recombination even if the electron transport ability is not so high. Even if such a material is used, the effect of improving the light emission efficiency is equivalent to that of a material having a high electron transport capability. Therefore, the electron transport layer in the present invention may be synonymous with a hole blocking layer that can efficiently block the movement of holes.

  As a material satisfying such conditions, the material for a light-emitting element of the present invention is more preferable. However, quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, tropolone metal complexes, flavonol metal complexes, perylene derivatives, perinone derivatives, naphthalene. Conductor, coumarin derivative, pyridine derivative, quinoline derivative, quinoxaline derivative, benzoquinoline derivative, phenanthroline derivative, thiophene derivative, oxazole derivative, thiazole derivative, oxadiazole derivative, triazole derivative, benzothiazole derivative, benzoxazole derivative, benzimidazole derivative, Diphenylphosphorus oxide derivatives, silole derivatives, triphenylsilane derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, etc. That.

  The material for a light-emitting element in the present invention is used as an electron-transporting material because of its high electron transporting ability and hole blocking ability.

  The materials used for the hole transport layer, the light emitting layer, and the electron transport layer can be formed by laminating and mixing two or more kinds of substances, and each layer can be formed by using polyvinyl chloride as a polymer binder, 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 Used by dispersing in solvent-soluble resins such as resins and polyurethane resins, and curable resins such as phenol resins, xylene resins, petroleum resins, urea resins, melamine resins, unsaturated polyester resins, alkyd resins, epoxy resins, and silicone resins. Rukoto is also possible. The polymer binder is used to form a thermally stable thin film, and is usually formed by a coating method or an ink jet method.

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

  In the present invention, electrical 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, but the maximum luminance should be obtained with the lowest possible energy in consideration of the power consumption and lifetime of the element.

  The light emitting device of the present invention is suitable for use as a matrix type. In the present invention, the matrix refers to a matrix in which pixels for display are arranged in a lattice pattern, and a character or an image is displayed by a set of pixels. The shape and size of the pixel are determined by the application. For example, a square pixel with a side of 300 μm or less is usually used for displaying images and characters on a personal computer, monitor, television, and a pixel with a side of mm order is used for a large display such as a display panel. . In monochrome display, pixels of the same color may be arranged, but 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 light emitting device in the present invention is suitable for use as a segment type. In the present invention, the segment type 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.

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

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited to these examples.

Example 1 (Synthesis of ETM-1)
101 g of 8-amino-7-quinolinecarbaldehyde was reacted in 45 g of 1,3-diacetylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.), 100 g of 85% potassium hydroxide and 1800 ml of ethanol for 10 hours under reflux, and treated in the usual manner As a result, 100 g of 1,3-di (1,10-phenanthrolin-2-yl) benzene was obtained. 40.8 g of this 1,3-di (1,10-phenanthrolin-2-yl) benzene was reacted with 00 ml of phenyllithium (0.94M cyclohexane / ether solution) in 750 ml of toluene for 2.5 hours with ice cooling, Processed in the usual way. The obtained product was reacted with 118 g of nitrobenzene at 110 ° C. for 3 hours and treated in a conventional manner to obtain 22.8 g of ETM-1 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 9.75 (s, 1H), 8.72 (d · d, 2H), 8.57-8.17 (m, 12H), 7.90-7. 82 (m, 5H), 7.61-7.48 (m, 6H).

  Separate synthesis of ETM-1: 9.64 g of 1,10-phenanthroline was reacted with 100 ml of phenyllithium (1.07 M cyclohexane / ether solution) in 250 ml of toluene at 0 ° C. for 1.5 hours and treated in a conventional manner. The obtained product was reacted with 93.0 g of manganese dioxide at room temperature for 56 hours in 300 ml of dichloromethane and treated in a conventional manner to obtain 9.44 g of 2-phenyl-1,10-phenanthroline. To 0.34 ml of THF solution (25 ml) of 1,3-dibromobenzene, 7.35 ml of t-butyllithium (1.53 M pentane solution) was added at −78 ° C., and the mixture was stirred for 1 hour and then heated to 0 ° C. This solution was added to the above-obtained 2-phenyl-1,10-phenanthroline (1.44 g) in THF (85 ml), stirred at room temperature for 20 hours, and then treated in the usual manner. The obtained product was reacted with 8.50 g of manganese dioxide in 85 ml of dichloromethane at room temperature for 23 hours and treated in a conventional manner to obtain 1.08 g of ETM-1 represented by the following formula.

This ETM-1 was used for a light emitting device after sublimation purification at about 320 ° C. under a pressure of 1.0 × 10 ⁻³ Pa using an oil diffusion pump.

Example 2 (Synthesis of ETM-2)
1-bromonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) 11.9 g and 1.6 g of lithium were reacted in 58 ml of diethyl ether at room temperature for 3 hours, and the resulting deep purple solution was subjected to 1,4-di (1,10 -Phenanthrolin-2-yl) benzene To a suspension of 5.0 g of toluene (100 ml), dropwise at room temperature. After reacting at room temperature for 3 days, it was treated in a conventional manner. The obtained product was reacted with 100 g of manganese dioxide at room temperature for 3 hours in 400 ml of dichloromethane and treated in a conventional manner to obtain 1.14 g of ETM-2 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 8.55-7.16 (m, 30H).

  This ETM-2 was used for a light emitting device after sublimation purification as in Example 1.

Example 3 (Synthesis of ETM-3)
54.0 g of 2,7-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 136 ml of 680 ml of dichloromethane and 228 g of trifluoromethanesulfonic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise at 0 ° C. The mixture was reacted at 5 ° C. for 2 hours and then at room temperature for 1 day, and then treated in a conventional manner to obtain 143 g of 2,7-bis (trifluoromethanesulfonyloxy) naphthalene. 143 g of 2,7-bis (trifluoromethanesulfonyloxy) naphthalene is 216 ml of n-butyl vinyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), 113 ml of triethylamine, 1,3-bis (diphenylphosphino) propane (Tokyo Chemical Industry Co., Ltd.) )) 2.78 g, palladium acetate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.76 g and 680 ml of dimethylformamide were mixed and reacted at 70 to 85 ° C. for 2 days. It processed by the conventional method and obtained 40 g of 2,7- diacetylnaphthalene. 4.62 g of this 2,7-diacetylnaphthalene was reacted with 7.87 g of 8-amino-7-quinolinecarbaldehyde and 7.9 g of potassium hydroxide in 220 ml of ethanol at 60 ° C., treated in a conventional manner, and represented by the following formula 4.44 g of ETM-3 was obtained. ¹ H-NMR (CDCl ₃ , ppm): 9.29 (d · d, 2H), 8.97 (s, 2H), 8.64 (d · d, 2H), 8.41-8.27 ( m, 6H), 8.09 (d, 2H), 7.89-7.79 (m, 4H), 7.67 (d · d, 2H).

  This ETM-3 was used for a light emitting device after sublimation purification as in Example 1.

Example 4 (Synthesis of ETM-4)
5.48 g of ETM-3 synthesized by the method of Example 3 was reacted with 22.6 ml of phenyllithium (2.0 M cyclohexane / ether solution) in 200 ml of toluene at room temperature for 2 days and treated in a conventional manner. The obtained product was reacted with 100 g of manganese dioxide at room temperature for 2.5 hours in 400 ml of dichloromethane and treated in a conventional manner to obtain 0.93 g of ETM-4 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 8.96 (s, 2H), 8.86 (d · d, 2H), 8.61-8.51 (m, 4H), 8.42-8. 34 (m, 6H), 8.18 (d, d, 4H), 7.84 (m, 4H), 7.65-7.48 (m, 6H).

  This ETM-4 was used for a light emitting device after sublimation purification as in Example 1.

Example 5 (Synthesis of ETM-5)
4.60 g of ETM-5 represented by the following formula was obtained in the same manner as in Example 3, except that 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2,7-dihydroxynaphthalene. ¹ H-NMR (CDCl ₃ , ppm): 9.22 (d · d, 2H), 8.39 (d, 2H), 8.29 (d · d, 2H), 8.16 (d, 2H) 7.98-7.85 (m, 8H), 7.67-7.54 (m, 4H).

  In addition, this ETM-5 was used for the light emitting element after performing sublimation purification in the same manner as in Example 1.

Example 6 (Synthesis of ETM-6)
1,3-dibromobenzene (Tokyo Chemical Industry Co., Ltd.) 4.03 g, 4-acetylphenylboronic acid (Aldrich) 7.0 g, potassium carbonate 11.8 g, tetrakis (triphenylphosphine) palladium (Tokyo Kasei) 0.987 g (manufactured by Kogyo Co., Ltd.), 35 ml of water, and 85 ml of 1,4-dioxane were mixed and reacted at 100 ° C. for 1 day. It processed by the conventional method and obtained 3.8g of 1, 2- di (4-acetylphenyl) benzene. 3.7 g of 1,2-di (4-acetylphenyl) benzene was reacted with 4.26 g of 8-amino-7-quinolinecarbaldehyde and 3.89 g of potassium hydroxide in 120 ml of ethanol at 60 ° C. and treated in a conventional manner. As a result, 6.52 g of ETM-6 represented by the following formula was obtained. ¹ H-NMR (CDCl ₃ , ppm): 9.21 (d · d, 2H), 8.27-8.21 (m, 8H), 8.06 (d, 2H) 7.80-7.72 (M, 4H), 7.61 (d · d, 2H), 7.56-7.51 (m, 4H), 7.41 (d, 4H).

  This ETM-6 was used for a light emitting device after sublimation purification as in Example 1.

Example 7 (Synthesis of ETM-7)
8.4 g of ETM-7 represented by the following formula was obtained in the same manner as in Example 6 except that 1,3-dibromobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 1,2-dibromobenzene. ¹ H-NMR (CDCl ₃ , ppm): 9.26 (d · d, 2H), 8.48 (d, 4H), 8.35-8.16 (m, 6H), 8.01 (s, 1H), 7.90-7.63 (m, 13H).

  This ETM-7 was used for a light emitting device after sublimation purification as in Example 1.

Example 8 (Synthesis of ETM-8)
In the same manner as in Example 7 except that 3-acetylphenylboronic acid (manufactured by Aldrich) was used instead of 4-acetylphenylboronic acid, 4.94 g of ETM-8 represented by the following formula was obtained. ¹ H-NMR (CDCl ₃ , ppm): 9.20 (d · d, 2H), 8.53 (t, 2H), 8.39 (d, 2H), 8.33-8.16 (m, 6H), 8.07 (s, 1H), 7.83-7.59 (m, 13H).

  This ETM-8 was used for a light emitting device after sublimation purification in the same manner as in Example 1.

Reference Example 1 (Synthesis of ETM-9)
5.12 g of ETM-9 represented by the following formula was obtained in the same manner as in Example 3 except that 1-amino-2-naphthalenecarbaldehyde was used instead of 8-amino-7-quinolinecarbaldehyde. _{^{1 H-NMR (CDCl 3,}} ppm): 8.40 (d, 2H), 8.10 (m, 2H), 7.82-7.32 (m, 18H).

  This ETM-9 was used for a light emitting device after sublimation purification as in Example 1.

Example 9 (Synthesis of ETM-10)
1-Bromo-4-t-butylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.88 g and 0.76 g of lithium were reacted in 50 ml of diethyl ether under reflux for 5 hours. Di (1,10-phenanthrolin-2-yl) benzene was added dropwise to 4.0 g of toluene suspension (150 ml) under ice cooling. The reaction was carried out for 1 hour under ice-cooling and then treated in the usual manner. The obtained product was reacted with 66 g of manganese dioxide at room temperature for 30 minutes in 150 ml of dichloromethane and treated in a conventional manner to obtain 3.65 g of ETM-10 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 9.81 (s, 1H), 8.71 (d · d, 2H), 8.51-8.38 (m, 8H), 8.31 (d, 2H), 8.14 (d, 2H), 7.88-7.81 (m, 5H), 7.58 (d, 4H), 1.43 (s, 18H).

  In addition, this ETM-10 was used for the light emitting element after performing sublimation purification in the same manner as in Example 1.

Example 10 (Synthesis of ETM-11)
5-Bromo-m-xylene (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.18 g and 0.92 g of lithium were reacted in 50 ml of diethyl ether under reflux for 5 hours, and the resulting gray solution was subjected to 1,3-di (1 , 10-phenanthrolin-2-yl) benzene The solution was added dropwise to 3.63 g of a toluene suspension (100 ml) under ice cooling. The mixture was reacted at room temperature for 2 hours and then treated in a conventional manner. The obtained product was reacted with 63 g of manganese dioxide at room temperature for 2 hours in 200 ml of dichloromethane and treated in a conventional manner to obtain 1.4 g of ETM-11 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 9.53 (s, 1H), 8.72 (d · d, 2H), 8.46-8.14 (m, 12H), 7.85-7. 79 (m, 5H), 7.13 (s, 2H), 2.47 (s, 12H).

  This ETM-11 was used for a light emitting device after sublimation purification as in Example 1.

Example 11 (Synthesis of ETM-12)
4-Bromotoluene (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.84 g and 1.1 g of lithium were reacted in 60 ml of diethyl ether under reflux for 5 hours, and the resulting gray solution was converted into 1,3-di (1,10- Phenanthrolin-2-yl) benzene was added dropwise to 4.34 g of a toluene suspension (100 ml) under ice cooling. The reaction was allowed to proceed for 2 hours under ice-cooling, followed by a conventional process. The obtained product was reacted with 75 g of manganese dioxide at room temperature for 2 hours in 200 ml of dichloromethane and treated in a conventional manner to obtain 2.1 g of ETM-12 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 9.72 (s, 1H), 8.72 (d · d, 2H), 8.53-7.36 (m, 19H), 2.48 (s, 6H).

  This ETM-12 was used for a light emitting device after sublimation purification as in Example 1.

Example 12 (Synthesis of ETM-13)
1-bromonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) 3.57 g and 0.48 g of lithium were reacted in 50 ml of diethyl ether at room temperature for 3 hours, and the resulting deep purple solution was treated with 1,3-di (1,10 -Phenanthrolin-2-yl) benzene To toluene suspension (100 ml) of 2.5 g was added dropwise under ice cooling. The mixture was reacted at room temperature for 2 hours and then treated in a conventional manner. The obtained product was reacted with 50 g of manganese dioxide at room temperature for 15 minutes in 500 ml of dichloromethane and treated in a conventional manner to obtain 0.4 g of ETM-13 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 9.43 (s, 1H), 9.02 (d, 2H), 8.53 (d, 2H), 8.40 (d, 2H), 8.29 -7.43 (m, 23H).

  In addition, this ETM-13 was used for the light emitting element after performing sublimation purification in the same manner as in Example 1.

Reference Example 2 (Synthesis of ETM-14)
2.5 g of 1,4-di (1,10-phenanthrolin-2-yl) benzene and 11.5 ml of phenyllithium (2.0 M cyclohexane / ether solution) in 100 ml of toluene for 1 hour under ice-cooling and then at room temperature The mixture was reacted for 4 hours and treated in a conventional manner. The obtained product was reacted with 50 g of manganese dioxide at room temperature for 5 minutes in 400 ml of dichloromethane and treated in a conventional manner to obtain 0.80 g of ETM-14 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 8.75 (s, 4H), 8.53 (d, 4H), 8.39-8.18 (m, 8H), 7.84 (s, 4H) 7.65-7.50 (m, 6H).

  This ETM-14 was used for a light emitting device after sublimation purification as in Example 1.

Example 13 (Synthesis of ETM-15)
1-Bromo-4-t-butylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) 3.68 g and 0.48 g of lithium were reacted in 50 ml of diethyl ether under reflux for 5 hours. Di (1,10-phenanthrolin-2-yl) benzene was added dropwise to 2.5 g of a toluene suspension (150 ml) under ice cooling. The reaction was allowed to proceed for 3 hours under ice-cooling and then treated in the usual manner. The obtained product was reacted with 55 g of manganese dioxide at room temperature for 15 minutes in 400 ml of dichloromethane and treated in a conventional manner to obtain 1.66 g of ETM-15 represented by the following formula. ¹ H-NMR (CDCl ₃ , ppm): 8.73 (s, 4H), 8.45-8.15 (m, 12H), 7.82 (s, 4H), 7.62-7.12 ( m, 4H), 1.40 (s, 18H).

  This ETM-15 was used for a light emitting device after sublimation purification as in Example 1.

Example 14
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” (manufactured by Furuuchi Chemical Co., Ltd.) 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. By the resistance heating method, first, copper phthalocyanine was deposited to 20 nm as a hole injecting material, and 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl was deposited to 100 nm as a hole transporting material. Next, a triskinolinol aluminum complex (Alq3) was laminated to a thickness of 50 nm as a light emitting material. Next, the above-mentioned ETM-1 was laminated to a thickness of 100 nm as an electron transport material. Next, after doping the organic layer with 0.5 nm of lithium, aluminum was vapor-deposited with a thickness of 200 nm to form a 5 × 5 mm square device. The film thickness mentioned here is a display value of a crystal oscillation type film thickness monitor. When a direct current of 1 mA was passed through the light emitting element, green light emission with a luminance of 200 candela / square meter was obtained. 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 driving voltage at this time was 5.5V. The durability of the light-emitting element was extremely excellent, and the luminance of 85% was maintained in 1000 hours under a constant current driving condition of 1 mA.

  Further, when this light emitting element was driven in a vacuum cell by 1 mA pulse (Duty ratio 1/60, current value at pulse 60 mA), good light emission was confirmed.

Examples 15-26
A light emitting device was fabricated in exactly the same manner as in Example 14 except that the materials listed in Table 1 were used as the electron transporting material. Table 1 shows the evaluation results of the obtained light-emitting element.

Comparative Example 1
A light emitting device was produced in the same manner as in Example 14 except that ETM-16 represented by the following formula was used as the electron transport material. When a direct current of 1 mA was passed through the light emitting element, green light emission with a luminance of 200 candela / square meter was obtained. The drive voltage at this time was 7.0V. The luminance of this light emitting element was halved in 900 hours under a constant current driving condition of 1 mA.

Comparative Example 2
A light emitting device was produced in the same manner as in Example 14 except that ETM-17 represented by the following formula was used as the electron transporting material. When a direct current of 1 mA was passed through the light emitting element, green light emission with a luminance of 190 candela / square meter was obtained. The drive voltage at this time was 6.8V. The luminance of this light emitting element was halved in 1000 hours under a constant current driving condition of 1 mA.

Example 27
Trisquinolinol aluminum complex (Alq3) as the host material and 4- (dicyanomethylene) -2-tbutyl-6- (1,1,7,7-tetramethyljulolidyl-9- as the guest material A light emitting device was produced in the same manner as in Example 14 except that enyl) -4H-pyran (DCJTB) was used so that the doping concentration was 2%. When a direct current of 1 mA was passed through the light emitting element, red-orange light emission with a luminance of 200 candela / square meter was obtained. The driving voltage at this time was 5.5V. The durability of the light-emitting element was extremely excellent, and the luminance of 80% was maintained in 1000 hours under a constant current driving condition of 1 mA.

Examples 28-39
A light emitting device was fabricated in exactly the same manner as in Example 27 except that the materials listed in Table 2 were used as the electron transporting material. Table 2 shows the evaluation results of the obtained light-emitting element.

Comparative Example 3
A light emitting device was fabricated in exactly the same manner as in Example 27 except that the above ETM-16 was used as the electron transport material. When a direct current of 1 mA was passed through the light emitting element, red-orange light emission with a luminance of 180 candela / square meter was obtained. The driving voltage at this time was 7.5V. The luminance of this light emitting element was halved in 1000 hours under a constant current driving condition of 1 mA.

Comparative Example 4
A light emitting device was fabricated in exactly the same manner as in Example 27 except that ETM-17 was used as the electron transport material. When a direct current of 1 mA was passed through the light emitting element, red-orange light emission with a luminance of 180 candela / square meter was obtained. The driving voltage at this time was 7.3V. The luminance of this light emitting element was halved in 1000 hours under a constant current driving condition of 1 mA.

Example 40
Other than using 4,4'-bis (diphenylvinyl) biphenyl (DPVBi) as the host material and bis (carbazolylvinyl) biphenyl (BCZVBi) as the guest material so that the doping concentration is 5% A light emitting device was fabricated in the same manner as in Example 27 . When a direct current of 1 mA was passed through the light emitting element, blue light emission with a luminance of 190 candela / square meter was obtained. The driving voltage at this time was 4.8V. As the host material crystallized over time, the luminance of this light emitting element was reduced by half in 100 hours under a constant current driving condition of 1 mA.

Comparative Example 5
A light emitting device was fabricated in exactly the same manner as in Example 40 , except that ETM-17 was used as the electron transport material. When a direct current of 1 mA was passed through the light emitting device, blue light emission with a luminance of 150 candela / square meter was obtained. The driving voltage at this time was 6.5V. The luminance of this light emitting element was halved in 10 hours under a constant current driving condition of 1 mA.

Example 41
1,4-diketo-2,5-bis (3,5-dimethylbenzyl) -3,6-bis (4-methylphenyl) pyrrolo [3,4-c] pyrrole as the host material and 4 as the guest material , 4-difluoro-1,3,5,7-tetraphenyl-4-bora-3a, 4a-diaza-indacene was used in exactly the same manner as in Example 27 except that the doping concentration was 1%. An element was produced. When a direct current of 1 mA was passed through the light emitting element, red light emission with a luminance of 210 candela / square meter was obtained. The driving voltage at this time was 5.2V. The durability of the light-emitting element was extremely excellent, and the luminance of 80% was maintained in 1000 hours under a constant current driving condition of 1 mA.

Examples 42-53
A light emitting device was fabricated in exactly the same manner as in Example 41 except that the materials listed in Table 3 were used as the electron transporting material. Table 3 shows the evaluation results of the obtained light-emitting element.

Comparative Example 6
A light emitting device was fabricated in exactly the same manner as in Example 41 except that the above ETM-16 was used as the electron transport material. When a direct current of 1 mA was passed through the light emitting device, red light emission with a luminance of 200 candela / square meter was obtained. The driving voltage at this time was 6.5V. The luminance of this light emitting element was halved in 1000 hours under a constant current driving condition of 1 mA.

Example 54
A glass substrate (manufactured by Asahi Glass Co., Ltd., 15Ω / □, electron beam evaporation product) on which ITO transparent conductive film is deposited to 150 nm is cut into 30 × 40 mm, and 300 μm pitch (remaining width 270 μm) × 32 stripes by photolithography. Patterned into a shape. One side of the ITO stripe in the long side direction is expanded to a 1.27 mm pitch (opening width 800 μm) in order to facilitate electrical connection with the outside. 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 ⁻⁴ Pa or less. First, 4,4′-bis (N- (m-tolyl) -N-phenylamino) biphenyl is deposited as a hole transport material by 150 nm by resistance heating, and a triskinolinol aluminum complex is formed as a light emitting material to a thickness of 50 nm. Vapor deposited. Next, the above-mentioned ETM-1 was laminated to a thickness of 100 nm as an electron transport material. The film thickness mentioned here is a display value of a crystal oscillation type film thickness monitor. Next, the mask having 16 250 μm openings (corresponding to the remaining width of 50 μm and 300 μm pitch) formed by wet etching on a 50 μm thick Kovar plate was replaced in a vacuum so as to be orthogonal to the ITO stripe. And it fixed with the magnet from the back so that an ITO board | substrate might closely_contact | adhere. And after doping lithium with a 0.5 nm organic layer, aluminum was vapor-deposited 200 nm, and the 32x16 dot matrix element was produced. When this element was driven in matrix, characters could be displayed without crosstalk.

Claims (2)

A light-emitting element in which at least a light-emitting layer and an electron transport layer are sequentially stacked between an anode and a cathode and emits light by electric energy, and the electron transport layer includes a light-emitting element material represented by the general formula (1).

(Here, A is a substituent having a 1,10-phenanthroline skeleton. B is represented by at least one selected from a benzene ring, a terphenyl skeleton, and a naphthalene ring, provided that B is a benzene ring. When all A include an alkyl group and / or an aryl group in the skeleton, n is 2. Also, all 1,10-phenanthroline skeletons are bonded to B at the 2-position, provided that Excluding the compound represented by formula (2).

_(Wherein, the combination of L _1, Y 23 _{to Y 29} and _Y 33 _{to Y 39} is either of the following [1] to [48].)

B in the general formula (1) is 1,4-phenylene group, 1,3-phenylene group, 1,6-naphthylene group, 1,7-naphthylene group, 2,6-naphthylene group, 2,7-naphthylene group. 2. The light emitting device according to claim 1, wherein the light emitting device is at least one selected from terphenyl groups in which at least one benzene ring is linked at the ortho position.