JPH0333184A - Organic electroluminescent element - Google Patents

Abstract

PURPOSE:To obtain the title element which is excellent in heat resistance and formability into thin film, can be prepared in a good yield, and emits light with high luminance at a low applied voltage by using a specified compound having skeleton similar to that of distyrylbenzene as the luminescent material. CONSTITUTION:An organic electroluminescent element to formed by using as the luminescent material a compound having a structure similar to that of distyrylbenzene shown by the formula X-CH=CH-Y-CH=CHZ (wherein X and Z may be the same of different and are each aryl or a monovalent aromatic heterocyclic group having only one N or S atom, and Y is arylene or a divalent aromatic heterocyclic group having only one N or S atom, provided that any one of X, Y, and Z is an aromatic heterocyclic group) {e.g. 1,4-bis[2-(3- N-ethylcarbazolyl)vinyl]benzene of the formula}. This element has a structure wherein an anode, a hole injection transfer layer, a luminescent layer, and a cathode are laminated in order.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a novel organic electroluminescent device. More specifically, the present invention relates to an organic electroluminescent device that has excellent heat resistance, can be manufactured with high yield, and can emit high-intensity light from blue-green to green with a low applied voltage.

[Conventional technology]

Recently, electroluminescent elements (hereinafter referred to as EL elements) have been widely used in various display devices because they are self-luminous and have high visibility, and because they are completely solid-state elements, they have excellent impact resistance. Its use as a light emitting device is attracting attention. There are two types of EL devices: inorganic EL devices that use inorganic compounds as light-emitting materials, and organic EL devices that use organic compounds. , research on its practical application is being actively conducted. The structure of the organic EL element is basically an anode/emitting layer/cathode structure, with a hole injection transport layer or an electron injection transport layer provided thereon as appropriate, for example, an anode/hole injection transport layer/emissive layer. Structures such as /cathode, anode/hole injection/transport layer/light emitting layer/electron injection/transport layer/cathode are known. The press hole injection transport layer has a function of transmitting holes injected from the anode to the light emitting layer, and the electron injection transport layer has a function of transmitting electrons injected from the cathode to the light emitting layer. There is. By interposing the hole injection transport layer between the light emitting layer and the anode, many holes are injected into the light emitting layer with a lower electric field, and furthermore, holes are injected into the light emitting layer from the cathode or the electron injection transport layer. It is known that when the hole injection layer does not transport electrons, electrons are accumulated inside the light emitting layer near the interface between the hole injection layer and the light emitting layer, increasing the luminous efficiency ["
Applied Physics Letters, Volume 51, No. 9
13 pages (1987)]. Such organic EL devices include, for example, (1) an anode/hole injection/transport layer/light emitting device in which an aluminum complex of 8-hydroxyquinoline is used as the material for the emissive layer and a diamine compound is used as the material for the hole injection/transport layer; A stacked EL device consisting of a layer/cathode structure [Applied Physics Letters (Appl, Phys, Lett,) J Vol. 51, p. 913 (1987)], an aluminum complex of 8-hydroxyquinoline in the emission band Stacked type E consisting of anode/hole injection zone/organic emission zone/cathode configuration
L element (Japanese Unexamined Patent Publication No. 59-194393), (3) EL element (3) consisting of a positive i/hole injection band/emissive band/cathode structure, and in which the emissive band is formed of a host material and a fluorescent material.
European Patent Publication No. 281381) is known. However, in the EL devices of (1) and (2) above, although high-brightness light emission is obtained at low voltage, the temperature of the 8-hydroxyquinoline used as the luminescent material is about 300°C. Because thermal decomposition occurs easily at temperatures above this level, during vapor deposition, it is necessary to keep the temperature of the vapor deposition source as low as 300°C or below, close to the evaporation temperature, which slows down the vapor deposition rate and inevitably reduces device productivity. There are problems such as. In addition, the temperature control of the deposition source is difficult, making production unstable. It should be noted that in the EL devices of (1) and (2) above, the device cannot exhibit high performance unless a material for the light emitting layer with excellent thin film properties is selected. On the other hand, in the EL element (3), the host material includes
A preferred compound that can inject holes and electrons from the outside is 8-hydroxyquinoline, and a fluorescent material that can emit light in response to recombination of holes and electrons is used. In this case, the injection function that the emissive band (emissive layer) should have (the ability to inject holes from the anode or hole injection transport layer by applying an electric field, and the ability to inject electrons from the cathode or electron injection transport layer); Of the transport function (a function that allows holes and electrons to be transported by an electric field) and the light emission function (a function that provides a field for holes and electrons to recombine and connects this to light emission), injection function, transport function and A part of the luminescence function is carried out by the host substance, and since the fluorescent substance utilizes only a part of the luminescence function, it is contained in a trace amount (5 mol % or less) in the host substance. An EL element with such a configuration has a high luminance of about 1000 cd/m" with an applied voltage of about 10 V, and is capable of emitting light in the red region rather than green. However, this EL element usually uses 8- Since hydroxyquinoline is used, it has the same problems as the EL elements (1) and (2) above.

[Problem to be solved by the invention]

The present invention solves the problems with conventional organic EL elements that can emit light with high brightness at low voltages, has excellent heat resistance and thin film formation, can be manufactured with high yield, and can emit high brightness with low applied voltages. The purpose of this invention is to provide an organic EL element that can emit light of [Means for Solving the Problems] As a result of intensive research aimed at coupling the above objects, the present inventors found that a compound having a specific structure of a distyrylbenzene-like skeleton is necessary as a light-emitting layer. It has the essential injection function, transport function, and light emitting function, and has excellent heat resistance and thin film forming properties.There is no thermal decomposition during vapor deposition, and a stable thin film can be formed.In addition, the counter electrode (metal)
Since pinholes are less likely to occur during formation, by using a core compound as a light emitting material, an EL device with a higher yield can be obtained.Moreover, this EL device can produce high brightness ranging from blue-green to green by applying a low voltage. It was discovered that luminescence could be obtained, and based on this knowledge, the present invention was developed. That is, the present invention uses general 2X-CH as a luminescent material.
-Cl1-Y-C[l-CH-2-(1) (X and 2 in the formula are monovalent aromatic heterocyclic groups having only one nitrogen atom or sulfur atom as an aryl group or a heteroatom, respectively) groups, which may be the same or different from each other, and Y is an arylene group or a divalent aromatic heterocyclic group having only one nitrogen atom or sulfur atom as a heteroatom. The present invention provides an organic electroluminescent device characterized in that it uses a compound represented by the following formula, in which any one of X, Y, and 2 is an aromatic heterocyclic group. The present invention will be explained in detail below. In the organic EL device of the present invention, a compound represented by the general formula % (1) (wherein X, Y and 2 have the same meanings as above) is used as a luminescent material. The X and Z each contain only one heteroatom of an aryl group such as a phenyl group, a naphthyl group, an anthonyl group, or a nitrogen atom or a sulfur atom such as a thienyl group, a pyrrolyl group, a pyridyl group, a quinolyl group, a carbazolyl group, etc. It is a monovalent aromatic heterocyclic group. These aryl groups and aromatic heterocyclic groups may or may not have a substituent. Examples of the substituent include alkyl groups such as methyl group, ethyl group, isopropyl group, and t-butyl group, or halogen-substituted alkyl groups thereof, alkoxy groups such as methoxy group, ethoxy group, propoxy group, and butoxy group, and formyl group. , acyl groups such as an acetyl group, globionyl group, butyryl group, aralkyl groups such as benzyl group and phenethyl group, aryloxy groups such as phenoxy group and tolyloxy group, methoxycarbonyl group,
Alkoxycarbonyl groups such as ethoxycarbonyl, propoxycarbonyl and butoxycarbonyl groups; acyloxy groups such as acetyloxy, propionyloxy and butyryloxy groups; acylamino groups such as acetylamino, propionylamino and butyrylamino groups; various halogen atoms , carboxyl group, hydroxyl group, aminocarbonyl group, carbamoyl group, aminocarbonyl group such as dimethylaminocarbonyl group, aryloxycarbonyl group such as phenoxycarbonyl group, tolyloxycarbonyl group, xylyloxycarbonyl group, and general aryl group. Formula % Formula % () (R1 and R1 in the formula are each a hydrogen atom, an acyl group such as an alkyl group, an aldehyde group, a formyl group, an acetyl group, a glopionyl group, or an aryl group, and even if they are the same It's okay and they can be different from each other.
Alternatively, x may be bonded to each other to form a saturated five-membered ring or a saturated six-membered ring with or without a substituent,
(which may be bonded to the group substituted with lz to form a saturated five-membered ring or a saturated six-membered ring with or without a substituent), and the like. X and 2 in the general formula (1) may be the same or different, and may be bonded between the groups substituting them to form a saturated group with or without a substituent. A five-membered ring or a saturated six-membered ring may be formed. Y in the general formula (I) is an arylene group such as a phenylene group or a naphthylene group, or a nitrogen atom or an insulfur atom such as a chenylene group, a pyrrolylene group, a pyrrolylene group, a quinolylene group, or a carbacylylene group as a hetero atom.
It is a divalent aromatic heterocyclic group containing only Further, this arylene group or aromatic heterocyclic group may or may not have a substituent. Examples of this substituent include the substituents exemplified in the explanation of X and 2 above. In addition, Y may be a saturated five-membered ring or a saturated six-membered ring, which may or may not have a substituent, by bonding between the groups substituting it. Furthermore, in the compound represented by the general formula (1), any one of X% Y and Z must be an aromatic heterocyclic group. The compound represented by the general formula (1) has favorable characteristics for forming a light emitting layer of an organic EL device, but as disclosed in Japanese Patent Application No. 63-313932, This is due to the chemical structure of distyrylbenzene shown by the formula. Even if the phenylene group in this residue is replaced with another arylene group or a divalent aromatic heterocyclic group containing a nitrogen atom or a sulfur atom as a heteroatom,
Alternatively, even if the phenyl group bonded to both ends of the distyrylbenzene is replaced with another aryl group or a monovalent aromatic heterocyclic group containing only one nitrogen atom or sulfur atom as a heteroatom, luminescence can be achieved. The favorable properties for forming the layer are maintained. Furthermore, the above-mentioned arylene group or divalent aromatic heterocyclic group, or aryl group or -
Various substituents may be introduced into the valent aromatic heterocyclic group as long as the properties thereof are not impaired. Among the compounds represented by the above general formula (1), preferred compounds with particularly excellent thin film forming properties are aromatic heterocyclic groups when x, y, and z groups are aromatic heterocyclic groups. Examples include aromatic heterocyclic groups having or not having a substituent having 6 or more carbon atoms (excluding substituents) in the fused ring part, such as a quinolyl group, a quinolylene group, a carbazolyl group, or a carbacylylene group. Specific examples of the compound represented by the general formula (1) include:
The following can be mentioned: (1) (3) (4) (5) (6) (8) ■ ■ (9) (10) (11) (l 2) (13) C, 11°Ji (l 4) (l 5) ( 16) (l 7) (19) (20) (21) (22) (23) (24) Cal. The light-emitting layer in the EL element of the present invention is represented by the general formula (1)
For example, the compound represented by
Although it can be formed by forming a thin film by a known method such as a casting method or an LB method, a molecular deposition film is particularly preferable. Here, the molecular deposited film refers to a thin film formed by depositing the compound from a gas phase state, or a film formed by solidifying the compound from a solution state or liquid phase state, and usually this molecular deposited film is a thin film formed by the LB method (molecular cumulative film)
They can be distinguished from each other by differences in aggregate structure, higher-order structure, and functional differences resulting from these differences. As disclosed in Japanese Patent Application Laid-Open No. 194393/1983, the light-emitting layer is prepared by dissolving a binder such as a resin and the compound in a solvent to form a solution, and then applying this to a spin code. It can be formed into a thin film by a method or the like. There is no particular limit to the thickness of the light-emitting layer formed in this way, and it can be selected depending on the situation.
The thickness is usually selected in the range of 5 nm to 5 μm. The light-emitting layer in the EL element of the present invention has (1) an injection layer that can inject holes from the anode or the hole injection transport layer and can inject electrons from the cathode or the electron injection transport layer when an electric field is applied. (2) a transport function that moves injected charges (electrons and holes) using the force of an electric field; and (3) a light-emitting function that provides a field for recombination of electrons and holes, which leads to light emission. are doing. Furthermore, the ease with which holes are injected,
There may be a difference in the ease with which electrons are injected, and there may be a difference in the transport function represented by the mobility of holes and electrons, but it is preferable to move one of the charges. The compound represented by the general formula (R) used in this light-emitting layer generally has an ionization energy lower than about 6 OeV, so if an appropriate anode metal or anode compound is selected, it is relatively easy to inject holes, Also, the electron affinity is 2.8aV
Therefore, if an appropriate cathode metal or cathode compound is selected, it is relatively easy to inject electrons, and the electron and hole transport functions are also excellent. Furthermore, since the fluorescence in the solid state is strong, it has a great ability to convert the excited state of the metal compound, its aggregates, or crystals formed upon recombination of electrons and holes into light. There are various configurations of the EL element of the present invention, but basically, the light emitting layer is sandwiched between a pair of electrodes (an anode and a cathode), and if necessary, hole injection is performed. A transport layer or an electron injection transport layer may be provided. Specifically (1
) anode/emissive layer/cathode, (2) anode/hole injection transport layer/
Light emitting layer/cathode, (3) anode/hole injection transport layer/light emitting layer/
Examples include structures such as an electron injection transport layer/cathode. Although the hole injecting and transporting layer and the electron injecting and transporting layer are not necessarily required, the presence of these layers further improves the light emitting performance. In addition, in the device having the above structure, it is preferable that each device is supported by a substrate, and the substrate is not particularly limited, and may be made of materials conventionally used in organic EL devices, such as glass, transparent plastic, quartz, etc. You can use a hollow one. As the anode in the organic EL device of the present invention, an electrode material containing a metal, an alloy, an electrically conductive compound, or a mixture thereof having a large work function (4 eV or more) is preferably used. A specific example of such an electrode material is Au.
Metals such as CuI. Examples include conductive transparent materials such as ITO, SnO□, and ZnO. The anode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. When emitting light from this electrode, it is desirable that the transmittance be greater than 10%, and the sheet resistance of the electrode is preferably several hundred 0/port or less. Although the film thickness depends on the material, it is usually 10 nm to 1 μ.
m1 is preferably selected in the range of 10 to 200 nm. On the other hand, as a cathode, it has a small work function (4 eV or less).
Electrode materials made of metals, alloys, electrically conductive compounds, and mixtures thereof are used. Specific examples of such electrode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium/copper mixtures, Al/AJO! , indium, etc. The cathode can be manufactured by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Further, the sheet resistance of the electrode is preferably several hundreds of nanometers or less, and the film thickness is usually selected in the range of 10 nm to 1 μm, preferably 50 to 200 nm. In the device of the present invention, it is preferable that either the anode or the cathode be transparent or semi-transparent, since this allows light to be transmitted and extracted efficiently. The structure of the EL device of the present invention has various embodiments as described above. It has the function of transmitting holes injected from the anode to the light emitting layer, and by interposing this hole injection transport layer between the anode and the light emitting layer, many holes can be transferred with a lower electric field. is injected into the emissive layer, and furthermore, the electrons are injected into the emissive layer from the cathode or the electron injection transport layer. It is a device with excellent light emitting performance, such as being accumulated near the interface between the inner and outer surfaces, improving the light emitting efficiency. The hole transport compound used in the hole injection transport layer is arranged between two electrodes to which an electric field is applied, and when holes are injected from the anode, the hole transport compound is capable of appropriately transmitting the holes to the light emitting layer. Compounds that have a hole mobility of at least 10-"cm"/V-3 when applied with an electric field of, for example, 104 to io'V/cm are suitable. There are no particular limitations on such hole transport compounds as long as they have the above-mentioned preferable properties. Any material can be selected from among the known materials used for the injection transport layer. Examples of the charge transport material include triazole derivatives (described in U.S. Pat. No. 3,112,197, etc.), oxadiazole derivatives (described in U.S. Pat. No. 3,189,
447), imidazole derivatives (those described in Japanese Patent Publication No. 37-16096, etc.)
, polyaryl alkane derivatives (U.S. Pat. No. 3,615)
, 402 specification, 3,820,9J39 specification,
3,542.544, Japanese Patent Publication No. 1983-555, Japanese Patent Publication No. 51-10983, Japanese Unexamined Patent Publication No. 51-932
Publication No. 24, Publication No. 55-17105, Publication No. 56-41
Publication No. 48, Publication No. 55-108667, Publication No. 55-1
56953, 56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (
U.S. Patent No. 3,180,729, 4,278
, 746 specification, JP 55-88064, JP 55-88065, JP 49-105537, JP 55-51086, JP 56-80051, JP 56-88141, No. 57-45545, No. 54-112637, No. 55-7454
6), phenylenediamine derivatives (U.S. Patent No. 3,615,404, Japanese Patent Publication No. 5
No. 1-10105, No. 46-3712, No. 4
7-25336, JP 54-53435, JP 54-110536, JP 54-119925
(described in US Pat. No. 3,567.450, US Pat. No. 3.180,
Specification No. 703, Specification No. 3,240,597, No. 3
, 658,520, 4.232,103, 4,175,961 vi, 4,012
, 376 specification, JP 49-35702, JP 39-27577, JP 55-144250, JP 56-119132, JP 56-2243
No. 7, West German Patent No. 1,110,518, etc.), amino-substituted chalcone derivatives (described in U.S. Pat. No. 3,257,203, etc.), styryl anthracene derivatives (described in JP-A-56-46234, etc.),
Fluorenone derivatives (described in JP-A-54-110837, etc.), hydrazone derivatives (U.S. Patent No. 3
, 717,462, JP 54-59143, JP 55-52063, JP 55-52064.
Publication No. 55-46760, Publication No. 55-8549
Publication No. 5, Publication No. 57-11350, Publication No. 57-148
749), stilbene derivatives (JP-A-61-210363, JP-A-61-2)
No. 28451, No. 61-14642, No. 61
-72255 publication, 62-47646 publication, 62-47646 publication
No. 2-38674, No. 62-10652, No. 62-3()255, No. 60-93445, No. 60-94462, No. 60-174749, No. 60-175052 etc.)
etc. can be mentioned. In the present invention, these compounds can be used as hole transfer compounds, but the following porphyrin compounds (described in JP-A No. 63-295695 etc.), aromatic tertiary amine compounds and Styrylamine compounds (U.S. Pat. No. 4,127,412, JP-A-53-27033, JP-A-54-58445, JP-A-54-149634, JP-A-54-64299, JP-A-55-794509) Publication No. 55-14425
Publication No. 0, Publication No. 56-1!9132, Publication No. 61-29
No. 5558, No. 61-98353, No. 63-
It is preferable to use the aromatic tertiary amine compound (described in Japanese Patent No. 295695, etc.), especially the aromatic tertiary amine compound. Representative examples of the porphyrin compounds include porphine, 1,10,15.20-tetraphenyl-21H,23H-porphine copper (n), 1,10,
15.20-tetraphenyl-21H,23H-porphine zinc (II), 5.10,15.20-tetrakis(pentafluorophenyl)-21H,23H-porphine, silicon 7 thalocyanine oxide, aluminum phthalocyanine chloride, phthalocyanine ( metal-free),
Examples include dilithium phthalocyanine, copper tetramethyl 7-thalocyanine, #47 thalocyanine, chromium 7-thalocyanine, zinc phthalocyanine, lead phthalocyanine, titanium phthalocyanine oxide, magnesium phthalocyanine, copper octamethyl phthalocyanine, and the like. Representative examples of the aromatic tertiary amine compounds and styrylamine compounds include N,N,N',N'-tetraphenyl-4,4'-diaminobiphenyl, NIN'godiphenyl-N,N'- Di(3-methylphenyl)-4,4'-
Diaminobiphenyl, 2.2-bis(4-di-p-tolylaminophenyl)propane, 1.1-bis(4-di-
p-tolylaminophenyl)cyclohexane, N, N,
N″, N′-tetra-p-)lylu-4,4″-diaminobiphenyl, l,l-bis(4-di-p-tolylaminophenyl)-4-7enylcyclohexane, bis(4-
Dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N,N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4' Diaminobiphenyl, N,
N,N',N'-tetra7e:4.4''-diaminodiphenyl ether, 4.4'-bis(diphenylamino)fordiphenyl, N,N,N-tri(p-tolyl)amine, 4- (di-p-tolylamino)-4″-[
4(p-)lylamino)styryl]stilbene, 4
-N, N-';phenylamino(2-'; phenylvinyl)benzene, 3-methoxy-4'-N, N-diphenylaminostilbene, N-phenylcarbazole and the like. The hole injection transport layer in the device of the present invention may be composed of a single layer consisting of these hole transport compounds 111i or 211 or more, or may be composed of a hole injection transport layer made of a compound different from the above layer. It may also be one in which transport layers are laminated. On the other hand, II of (3) above! The electron injection transport layer in the above EL element is made of an electron transfer compound and has the function of transmitting electrons injected from the cathode to the light emitting layer. There are no particular limitations on such electron transfer compounds, and any one can be selected and used from conventionally known compounds. Preferred examples of the electron transfer compound include nitro-substituted fluorenone derivatives such as, thiopyrane dioxide derivatives such as, diphenylquinone derivatives such as ["Polymer Preprints Japan" Vol. 37, No. 3, Page 681 (1988)
], or compounds such as "Japanese Journal of Applied Physics (J, J. AI) ps, phys,) J Vol. 27, L 269° (
198B)] and anthraquinodimethane derivatives (JP-A-57-149259, JP-A-57-149259, JP-A-57-149259), etc.
-55450, 61-225151, 61-233750, 63-104061, etc.), fluorenylidenemethane derivatives (JP-A-60-69657, 61- 14376
4, No. 61-148159, etc.), anthrone derivatives (those described in JP-A No. 61-225151, JP-A No. 61-233750, etc.) rAppl, Phys, Lett, J No. 55 Volume, @14
Examples include oxadiazole derivatives (t-B u is a tertiary-butyl group) disclosed on page 89 (1989). Next, an example of a suitable method for manufacturing the organic EL device of the present invention will be explained for each device of each structure. To explain the method for manufacturing an EL device consisting of the above-described anode/emitting layer/cathode, first, a thin film of a desired electrode material, for example, an anode material, is deposited on a suitable substrate to a thickness of 1 μm or less, preferably in the range of 10 to 200 nm. After forming an anode by a method such as vapor deposition or sputtering to have a film thickness of will be established. Examples of methods for thinning the luminescent material include spin code method,
Although there are casting methods, LB methods, vapor deposition methods, etc., the vapor deposition method is preferable because a homogeneous film is easily obtained and pinholes are less likely to be generated. When this vapor deposition method is used to thin the luminescent material, the deposition conditions vary depending on the type of luminescent material used, the desired crystal structure and association structure of the molecular deposited film, but generally the port heating temperature is 50°C. ~4
00°C, degree of vacuum 10-'~lO-''Pas deposition rate 0.01-50 nm/see, substrate temperature-
It is desirable to appropriately select the film thickness from 50 to +3QQ°C and from 5 nm to 5 pm. Next, after forming this light-emitting layer, a thin film made of a cathode material is formed thereon to a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, by a method such as vapor deposition or sputtering, By providing a cathode, a desired organic EL element can be obtained. Note that in manufacturing this EL element, it is also possible to reverse the manufacturing order and manufacture the cathode, the light emitting layer, and the anode in this order. Next, E consisting of anode/hole injection/transport layer/emissive layer/cathode
To explain the manufacturing method of the L element, first, the anode is formed in the same manner as in the case of the EL element described above, and then a thin film made of a hole transporting compound is formed by vapor deposition, etc., and hole injection is performed. Provide a transport layer. The vapor deposition conditions at this time may be based on the vapor deposition conditions for forming a thin film of the luminescent material. Next, on this hole injection transport layer, a light emitting layer and a cathode are sequentially placed.
A desired EL element can be obtained by providing it in the same manner as in the case of manufacturing the EL element. In the production of this EL element, the production order is also reversed to form a cathode, a light-emitting layer,
It is also possible to manufacture the hole injection transport layer and the anode in this order. Furthermore, to explain the method for manufacturing an EL device consisting of an anode/hole injection/transport layer/light emitting layer/electron injection/transport layer/cathode, first, the anode, hole injection After sequentially providing a transport layer and a light-emitting layer, a thin film made of an electron transfer compound is formed by vapor deposition on the light-emitting layer to provide an electron injection and transport layer, and then a cathode is placed on top of the EL layer. A desired EL element can be obtained by providing it in the same manner as in the case of manufacturing the element. In the production of this EL element, the order of production may be reversed, and the cathode, electron injection and transport layer, light emitting layer, hole injection and transport layer, and anode may be produced in this order. When applying a DC voltage to the organic EL device of the present invention obtained in this way, when a voltage of about 1 to 30 V is applied with the anode as + polarity and the cathode as - polarity, the light emission becomes transparent or translucent. It can be observed from the electrode side. Furthermore, even if a voltage with the opposite polarity is applied, no current flows and no light is emitted. Further, when applying an alternating voltage, light is emitted only when the anode is in a positive state and the cathode is in a negative state. Note that the waveform of the applied alternating current may be arbitrary. Next, the light emitting mechanism of the EL element will be explained using an example of a structure of anode/hole injection/transport layer/light emitting layer/cathode. When a voltage is applied with the anode as + polarity and the cathode as - polarity, holes are injected from the anode into the hole injection transport layer by an electric field. The injected holes are transported within the hole injection transport layer toward the interface with the light-emitting layer, and are injected or transported from this interface to a region where a light-emitting function is expressed (for example, the light-emitting layer). On the other hand, electrons are injected from the cathode into the light-emitting layer by an electric field, are further transported, and recombine with holes in the region where holes exist, that is, the region where the light-emitting function is expressed (in this sense, the region is recombined with holes). (It can also be called a joint area). When this recombination occurs, an excited state of molecules, aggregates thereof, crystals, etc. is formed, and this is converted into light. Note that the recombination region may be the interface between the hole injection transport layer and the light-emitting layer, the interface between the light-emitting layer and the cathode, or the central part of the light-emitting layer away from both interfaces. This varies depending on the type of compound used, its association and crystal structure. [Examples] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 Glass substrate provided with an ITO transparent electrode with a film thickness of 1100 nm (25 x 75 x 1.1 Ding Suiz, manufactured by HOYA)
was used as a transparent support substrate, which was ultrasonically cleaned with inpropyl alcohol for 30 minutes, and then immersed in inpropyl alcohol for cleaning. This transparent support substrate was dried with dry nitrogen gas and fixed on a substrate holder of a commercially available vacuum evaporation apparatus, while it was placed on a molybdenum resistance heating boat with N,N''-diphenyl-N,N''-di(3- methylphenyl)-4,4'
Diaminobiphenyl (TPD) 200119 was added, and all-trans structure 1,4-bis(2-(3-N-ethylcarbazolyl)vinyl)benzene [compound of formula (9)] was placed in another molybdenum resistance heating boat. ] was put in 200B and attached to the vacuum evaporation equipment. Then, the vacuum chamber was
After reducing the pressure to IO'''Pa, electricity was applied to the heating boat containing TPD to heat it to 220°C, and the deposition rate was 0.
．． A hole injection transport layer having a thickness of 50 nm was provided by vapor deposition on a transparent support substrate at a rate of 1 to 0.7 nm/sec. Further, the boat containing 1,4-bis(2-(3-N-ethylcarbazolyl)vinyl)benzene was energized to
Heating to 15°C, deposition rate 0.1 nm/sec
Then, the film was deposited on the hole injection transport layer to a film thickness of 60 nm.
A light emitting layer was provided. Note that the temperature of the substrate during vapor deposition was room temperature. Next, the vacuum chamber was opened and a stainless steel mask was placed on top of the light emitting layer.Meanwhile, 3g of magnesium was placed in a molybdenum resistance heating boat, copper was placed in the crucible of the electron beam evaporation device, and vacuum was applied again. After reducing the pressure in the tank to 2X10-'Pa, energize the port containing magnesium.
Depositing magnesium at a deposition rate of 4 to 5 nm/see,
At this time, copper is simultaneously heated by an electron beam to evaporate copper at a evaporation rate of 0.3 to 0.5 nm/see, and a counter electrode formed from the mixture of magnesium and copper is formed to achieve the desired goal. Fabricate an EL element. When 15 V DC was applied to this device using the ITO electrode as the positive electrode and the counter electrode made of a mixture of magnesium and copper as the negative electrode, a current with a current density of 206 mA/cs+" flowed and blue-green light was emitted. The maximum emission wavelength at this time is 487 nm, the CIE chromaticity coordinates are x=0.15, )I-0,30, and the emission brightness is 750 cd.
/m". Example 2 A glass substrate (25 x 75 x 1.1 mm size, manufactured by HOYA) on which an ITO transparent electrode with a film thickness of 1100 nm was provided was used as a transparent support substrate, and this was ultrasonically cleaned with isopropyl alcohol for 30 minutes. The transparent support substrate was then washed by dipping it in isopropyl alcohol I. This transparent supporting substrate was dried with dry nitrogen gas and fixed to a substrate holder of a commercially available vacuum evaporation device.Meanwhile, 1 g of TPD200Il was placed in a molybdenum resistance heating boat. Furthermore, a trans-structured 1-(2-(2-(6-methylquinolyl))hinyl]-4-styrylbenzene [compound 3200 of formula (4)] was added to El's molybdenum resistance heating boat.
111 g was put therein and attached to a vacuum evaporation device. Next, after reducing the pressure in the vacuum chamber to 2.8X10-'Pa, the TPD
Electricity was applied to the heating port containing the above to heat it to 220° C., and vapor deposition was performed on the transparent support substrate at a vapor deposition rate of 0.1 to 0.3 nm/sec to provide a hole injection transport layer with a film thickness of 50 nm. Additionally, l -(2-(2-(6-methylquinolyl))
The port containing vinyl2-4-styrylbenzene was energized and heated to 211°C, and the deposition rate was 0.1-0.
A light emitting layer having a thickness of 60 nm was provided by vapor deposition on the hole injection transport layer at a rate of 5 nm/sec. Note that the temperature of the substrate during vapor deposition was room temperature. Next, the vacuum chamber was opened and a stainless steel mask was placed on top of the luminescent layer, while a molybdenum resistance heating boat l
After putting this magnesium 39 and copper into the crucible of the electron beam evaporation device, reducing the pressure in the vacuum chamber to 2XlO-'Pa again, energizing the port containing magnesium,
Depositing magnesium at a deposition rate of 4 to 5 nm/sec,
At this time, copper is simultaneously heated by an electron beam to evaporate copper at a evaporation rate of 0.1 to 0.3 nm/sec to form a counter electrode made of a mixture of magnesium and copper, thereby achieving the desired EL. Fabricate the device. When a direct current of 10 V was applied to this device using the ITO electrode as the positive electrode and the opposite electrode made of a mixture of magnesium and copper as the negative electrode, a current with a current density of 153 mA/cm" flowed and green light was emitted. The emission maximum wavelength is 505nm, the CIE chromaticity coordinates are x=0.20s y-0,41, and the emission brightness is 305cd.
/m'' Example 3 A glass substrate (25 x 75 x 1.1 ma + size, manufactured by HOYA) on which an ITO transparent electrode with a film thickness of 1100 nm was provided was used as a transparent support substrate, and this was ultrasonically cleaned with isopropyl alcohol for 30 minutes. The transparent support substrate was dried with dry nitrogen gas and fixed to a substrate holder of a commercially available vacuum evaporation device, while TPD200119 was placed in a molybdenum resistance heating boat. Then, the compound 12001119 of 1,4-bis(2-(quinolinyl)hinyl)benzene [formula (3)] having an all-trans structure was placed in another resistance heating boat made of molybdenum, and the boat was attached to a vacuum evaporation apparatus. 3XIO-'Pa
After reducing the pressure to
Deposited on a transparent support substrate at a rate of 50 nm/sec.
A hole injection transport layer was provided. Furthermore, 1,4-bis(2
-(Quinolyl)vinyl]benzene I; energize the port and heat to 211°C, vapor deposition rate 0.1-0.
A light emitting layer having a thickness of 60 nm was provided by vapor deposition on the hole injection transport layer at a rate of 5 nm/see. Note that the temperature of the substrate during vapor deposition was room temperature. Next, open the vacuum chamber, place a stainless steel mask on top of the nuclear luminescent layer, put 3 g of magnesium into a molybdenum resistance heating boat, put copper into the crucible of the electron beam evaporator, and vacuum again. After reducing the pressure in the tank to 1.2 x 10-'Pa, the boat containing magnesium was energized to deposit magnesium at a deposition rate of 5 nm/see.At the same time, copper was heated by an electron beam to achieve a deposition rate of 0. Copper was deposited at a rate of 1 to 0.3 nm/see to form a counter electrode made of a mixture of magnesium and copper. Further, this device was annealed at 70° C. for 30 seconds to produce the desired EL device. When a direct current of 15 V was applied using the ITO electrode of this device as a positive electrode and the opposing electrode made of a mixture of magnesium and copper as a negative electrode, a current with a current density of 161 mA/c- flowed and green light was emitted. The maximum emission wavelength at this time is 513n
m, CIE chromaticity coordinates are x-0, 20, y-0, '41.
The luminance was 136 cd/m''. Example 4 (ITO/hole injection layer/light emitting layer/electron injection layer/Mg:I
n) A glass substrate (25 x 75 x 1.1 mm size, manufactured by HOYA) on which an ITO transparent electrode with a film thickness of 1100 nm is provided was used as a transparent support substrate, and this was ultrasonically cleaned with isopropyl alcohol for 30 minutes, and immersed in isopropyl alcohol. It was washed and further washed with a UV ozone cleaning device manufactured by Samco International. This transparent support substrate was dried with dry nitrogen gas and fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while the N,N'-diphenyl-N,N'-di(3- methylphenyl)-4,4'-diaminobiphenyl (TPD)
Insert 200rtry, and then install an all-trans structure 1.4-bis (2-(3
-N-ethylcarbazolyl)vinyl]benzene [formula (A
)], and then put 200 mg of t-BuPBD [compound 1 of formula (B)] into another molybdenum port.
200 mg was added and attached to a vacuum evaporation device. Next, after reducing the pressure in the vacuum chamber to 4XIO-'Pa,
The heating boat containing TPD was energized and heated to 220°C, and the deposition rate was 0.1-0. A hole injection transport layer having a thickness of 50 nm was provided by vapor deposition on a transparent support substrate at a rate of Inm/sec. Further, the boat containing the compound of formula (A) is heated to 315° C. by applying electricity, and the vapor deposition rate is 0.1 to 0.
A light emitting layer having a thickness of 60 nm was provided by vapor deposition on the hole injection transport layer at a rate of 3 nm/sec. Furthermore, t-
The port containing BuPBD was energized and heated to 160° C., and an electron injection layer was provided on the light emitting layer at a deposition rate of 0.1 to 0.4 nm/sec. Note that the temperature of the substrate during vapor deposition was room temperature. Next, the vacuum chamber was opened, a stainless steel mask was placed on top of the luminescent layer, while 3 g of magnesium was put into the molybdenum resistance heating port, and indium was put into another resistance heating filament, and the vacuum chamber was opened again. 2XIO-'Pa
After reducing the pressure to
．． Copper was vapor-deposited at 2-0.3 nm/sec to form a counter electrode made of the mixture of magnesium and indium, thereby producing the intended EL element. The ITO electrode of this element was used as a positive electrode, and the counter electrode made of a mixture of magnesium and indium was used as a negative electrode.
When V was applied, the current density was 100 mA/cm"
A current flowed through the tube, emitting greenish-blue light. The brightness at this time was 670 c d/m''. 1 l (A) (t-BuPBD) (B) Example 5 (ITO/light emitting layer/electron injection layer/Mg:In) film thickness 11
A glass substrate on which a 00n ITO transparent electrode is provided (
25 x 75
It was ultrasonically cleaned for a minute, washed by immersion in isopropyl alcohol, and then washed in a UV ozone cleaning device manufactured by Samco International. This transparent support substrate was dried with dry nitrogen gas and fixed on a substrate holder of a commercially available vacuum evaporation apparatus, while it was placed on a molybdenum resistance heating boat using the formula (
Compound 20019 of A) was put thereinto, and t-BuPBD [compound 120019 of formula (B)] was put into another molybdenum resistance heating boat, which was then attached to a vacuum evaporation apparatus. Next, after reducing the pressure in the vacuum chamber to 2.8 X l O-'P a, electricity was applied to the heating port containing the compound of formula (A) to heat it to 315°C, and the vapor deposition rate was 0.1~ 0.
A light emitting layer having a thickness of 60 nm was provided by vapor deposition on a transparent support substrate at a rate of 7 nm/sec. Further, the boat containing t-BuPBD is heated to 162° C. by applying electricity, and is deposited on the light emitting layer at a deposition rate of 0.1 to 0.3 nm/sec to form an electron injection layer with a thickness of 60 nm. Provided. The temperature of the core substrate during vapor deposition was room temperature. Afterwards, a vacuum chamber was opened, and a stainless steel mask was placed on top of the luminescent layer. Meanwhile, magnesium 39 was placed in a resistance heating boat made of molybdenum. After putting indium into the resistance heating filament and reducing the pressure in the vacuum chamber to 2 Indium is heated and the deposition rate is 0.
Vapor depositing indium at 2 to 0.3 nm/sec,
The desired EL element was manufactured by using the mixture of magnesium and indium as the counter electrode. The ITO electrode of this element was used as a positive electrode, and the counter electrode made of a mixture of magnesium and indium was used as a negative electrode.
When a current of 70 mA/cm'' was applied, a current with a current density of 70 mA/cm'' was generated, and greenish-blue light was emitted.The luminance at this time was 800 cd/cm''. A glass substrate (25 x 75 x 1.1 mm size, manufactured by HOYA) on which an ITO transparent electrode with a film thickness of 1100 nm was provided was used as a transparent support substrate, and this was ultrasonically cleaned with isopropyl alcohol for 30 minutes and immersed in inpropyl alcohol. It was washed, and further washed with a Uv ozone cleaning device manufactured by Samco International Fin Naru Co., Ltd. This transparent support substrate was dried with dry nitrogen gas and fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while N,N'-diphenyl-N,N'di(3-methyl phenyl)-4,4°-diaminobiphenyl (T PD)
200 mg of all-trans structure compound 120 of formula (7) was added to another molybdenum resistance heating boat.
0 mg was added and attached to a vacuum evaporation device. Next, after reducing the pressure in the vacuum chamber to 3 x 10-'Pa, electricity was applied to the heating port containing the TPD to heat it to 220 ° C.
A hole injection transport layer having a thickness of 60 rim was provided by vapor deposition on a transparent support substrate at a vapor deposition rate of 0.1 to 0.7 nm/sec. Further, the boat containing the compound of formula (7) above was heated to 180°C by applying electricity, and the vapor deposition rate was 0.1 to 0.
．． A light emitting layer having a thickness of 90 nm was provided on the hole injection transport layer at a rate of 3 nm/sec. The temperature of the substrate during vapor deposition was room temperature.Next, the vacuum chamber was opened and a stainless steel mask was placed on top of the luminescent layer, while 3 g of magnesium was placed in a molybdenum resistance heating boat. , and put indium into a tungsten resistance heating boat, and then put the vacuum chamber into a 1.2x1
After reducing the pressure to 0-'Pa, the boat containing magnesium was energized to deposit magnesium at a deposition rate of 4 to 5 nm/see, while simultaneously heating indium.
Indium was evaporated at a evaporation rate Q of 2 to 0.3 nm/sec to form a counter electrode made of the mixture of magnesium and indium. Furthermore, this element was heated at 70℃ for 3
Annealing was performed for 0 seconds to produce the desired EL device. The ITO electrode of this device was used as a positive electrode, and the counter electrode made of a mixture of magnesium and indium was used as a negative electrode.
When V was applied, a current with a current density of t70 mA/c- flowed and yellow-green light was emitted. The brightness at this time is 4
2 c d/m''. [Effect 1 of the invention] The compound having a skeleton similar to distyrylbenzene, which is used as a light emitting material for the organic EL device of the present invention, has excellent heat resistance and thin film forming properties. Since thermal decomposition does not occur during vapor deposition and pinholes are less likely to occur, the EL device of the present invention using the compound as a light emitting material can be manufactured with a high yield.The organic EL device of the present invention , stable light emission from blue-green to green with high brightness can be obtained at low voltage, and it is suitably used as a light-emitting element in various display devices.

Claims (1)

[Claims] 1. As a luminescent material, the general formula: A monovalent aromatic heterocyclic group having only one sulfur atom, which may be the same or different, and Y is an arylene group or a nitrogen atom or sulfur atom as a heteroatom. A divalent aromatic heterocyclic group having only one atom, in which any one of X, Y, and Z is an aromatic heterocyclic group) was used. An organic electroluminescent device characterized by 2. The organic electroluminescent device according to claim 1, which has a light-emitting layer made of a compound represented by general formula (I). 3. The organic electroluminescent device according to claim 2, comprising a light emitting layer sandwiched between a pair of electrodes. 4. The organic electroluminescent device according to claim 3, comprising an anode, a hole injection transport layer, a light emitting layer, and a cathode stacked in this order. 5. The organic electroluminescent device according to claim 3, comprising an anode, a hole injection transport layer, a light emitting layer, an electron injection layer, and a cathode, which are laminated in this order. 6. The organic electroluminescent device according to claim 3, comprising an anode, a light emitting layer, an electron injection layer, and a cathode stacked in this order.