JP3888351B2 - EL device and hole-transporting condensate used in the production thereof - Google Patents

Description

  The present invention relates to an EL element utilizing a thin film electroluminescence (hereinafter simply referred to as EL) phenomenon, and can be used for a thin display or the like.

  An EL element is a light-emitting element that utilizes the electroluminescence (hereinafter referred to as EL) phenomenon of a phosphor used in a light-emitting layer, and is used as a self-luminous flat display element or a flat light source. Among the EL elements, an organic thin film EL element whose phosphor is an organic substance is a C.I. W. Developed by Tang et al., JP-A-59-194393, JP-A-63-246492, JP-A-63-295695, Applied Physics Letter Vol. 51, No. 12, p. 913 (1987). , And Journal of Applied Physics, Vol. 65, No. 9, p. 3610 (1989).

  In general, as shown in FIG. 1, an organic thin-film EL element has an anode (2), an organic hole injection transport layer (3), an organic light emitting layer (4), and a cathode (1) on a transparent insulating substrate (1). 5) The layers are stacked in this order, and are manufactured as follows.

  First, a transparent conductive film made of a composite oxide of indium and tin (hereinafter referred to as ITO) is deposited as an anode (2) on a transparent insulating substrate (1) such as glass or resin film by vapor deposition or sputtering. Form by law etc. Next, on this anode, 1,1-bis (4-di-p-tolylaminophenyl) can be formed as an organic hole injecting and transporting layer (3) so that an amorphous and smooth film can be formed to make it difficult to break down the device. ) Single layer film made of organic hole injection / transport material such as low molecular weight aromatic tertiary amine such as cyclohexane [glass transition temperature (Tg) 84 ° C.] or crystalline but highly resistant to redox A multilayer film in which phthalocyanine or the like is laminated on the ITO interface is formed with a thickness of about 100 nm or less.

  Further, an organic phosphor film such as tris (8-quinolinol) aluminum (hereinafter referred to as Alq) is formed on the organic hole injecting and transporting layer (3) as an organic light emitting layer (4) with a thickness of about 100 nm or less. And formed by vapor deposition. An organic thin film EL element is produced by forming an alloy film of Mg: Ag or the like as a cathode (5) on the organic light emitting layer with a thickness of about 200 nm by a co-evaporation method.

In the organic thin film EL device manufactured as described above, by applying a direct current low voltage between the electrodes, holes and electrons are injected into the organic light emitting layer, and light emission is caused by recombination thereof. Note that the DC low voltage applied to this element is usually 20 to 30 V or less, and a luminance of 1000 cd / m ² or more is obtained in an element using a Mg: Ag alloy for the cathode. If the organic light emitting layer is doped with a fluorescent dye having a high fluorescence quantum yield such as coumarin, pyran, or quinacridone by a method such as co-evaporation, the luminance of EL can be further increased by 2 times or more.

  According to Japanese Patent Laid-Open No. 7-65958, as shown in FIG. 2, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4 on the ITO anode, 4'-diamine (hereinafter abbreviated as TPD; melting point 159 to 163 ° C., Tg 67 ° C.) The hole transport layer is doped with a light emitting material such as rubrene to form an organic hole transport light emitting layer (6), and Alq is injected with organic electrons. By laminating as the transport layer (7), a relatively stable organic thin film EL element is obtained.

  However, most of the hole transport materials used in the above-described organic thin film EL devices have so far been occupied by low molecular weight compounds, many of which have a Tg of 100 ° C. or lower and low heat resistance. When the temperature reaches around Tg due to heat or heat generated during driving, it is often mixed with other layers or crystallized due to storage or use in a high temperature environment to cause pinholes, which often cause device deterioration or electrical short circuit.

  Moreover, since the solubility to organic solvents, such as toluene, is high, there existed a problem that it was difficult to laminate | stack a film | membrane further by the wet method using the same organic solvent, or patterning of the layer was difficult.

  As described above, the object of the present invention is to provide an EL element that is more heat resistant than an element using a conventional hole injecting and transporting material and difficult to electrically short-circuit, and a hole transporting condensate used in the production thereof. In addition, by cross-linking the layer containing the hole transporting condensate, the heat resistance and mechanical strength are increased and insolubilized in the solvent, enabling application to the cross-linked layer by a wet method. The object of the present invention is to provide an EL device that enables patterning of a layer containing a hole transporting condensate.

  The present invention relates to a hole transport obtained by addition condensation of a tertiary amine compound containing one or more triarylamine structures and having a para-position hydrogen on at least two aryl groups and a carbonyl compound. An EL device comprising a layer containing a functional condensate.

  As described above, according to the present invention, an EL element with high heat resistance can be obtained by using a hole transporting condensate having a high Tg produced by addition condensation of an aromatic tertiary amine and an aldehyde. Can do. Furthermore, when a hole-transporting condensate having a crosslinking group is used and crosslinked, an EL element having higher heat resistance can be obtained. When used as a hole transporting light emitting layer, the pattern of the hole transporting light emitting layer can be formed by mask exposure.

  Embodiments of the present invention will be described below. FIG. 1 shows an EL device according to the present invention having an anode (2), an organic hole injecting and transporting layer (3), an organic light emitting layer (4), a cathode (5), and a sealing layer (8) on a substrate (1). This is an example in which the sealing plate (10) is adhered and sealed with an adhesive material (9).

  FIG. 2 shows the efficiency of electron injection into the organic hole-transporting light-emitting layer (6) and the light-emitting layer, which serves as both the hole-injecting and transporting layer and the organic light-emitting layer, or suppresses the flow of holes to the cathode. This is a case of a two-layer structure of an organic electron injecting and transporting layer (7) having an effect.

  FIG. 3 shows a case where the organic hole injection / transport layer has a two-layer structure, and the ionization energy between the work function of the second hole injection / transport layer (12) and the anode as the first hole injection / transport layer (11). The efficiency of hole injection into the organic light-emitting layer (4) is improved by using a material having the above value and stable against oxidation and reduction, and the EL element can be driven at a low voltage and stabilized.

  FIG. 4 shows an example in which the organic hole injecting and transporting layer (3), the organic hole transporting and emitting layer (6), and the organic electron injecting and transporting layer (7) are composed of three layers.

  FIG. 5 shows an example in which the organic hole transporting light emitting layer (6) of FIG. 4 is patterned in red (R), green (G), and blue (B).

  It is possible depending on the material used to construct the same structure on the substrate in the reverse order from the cathode.

  The EL device according to the present invention is obtained by addition condensation of a tertiary amine compound containing one or more triarylamine structures and having at least two para groups on the aryl group being hydrogen and a carbonyl compound. Desirably, the hole transporting condensing compound may be an organic positive hole injection transport layer (3), a first positive hole injection transport layer (11), a second positive hole injection transport layer (12) of FIGS. The at least one layer in the hole transport light emitting layer (6) is used alone or in combination with a plurality of materials.

  Hereinafter, the material and the method for manufacturing the element will be described in more detail.

  The substrate (1) uses a transparent insulating material such as a plastic film such as glass or polyethersulfone. The substrate (1) is colored to improve contrast and resistance, and circularly polarizing filters, multilayer antireflection filters, ultraviolet absorption filters, RGB color filters, fluorescent wavelength conversion filters, silica coating layers, etc. are provided on the inner and outer surfaces. Also good.

  As the anode (2), a transparent electrode having a surface resistance of 1 to 50Ω / □ and a visible light transmittance of 80% or more is usually used. For example, an amorphous or microcrystalline transparent conductive film of ITO (work function 4.6 to 4.8 eV) or zinc oxide, or silver or copper having a thickness of about 10 nm or silver and copper for reducing resistance. Transparent insulation such as glass or plastic film by vacuum deposition or sputtering method with a structure in which an alloy is sandwiched between amorphous or microcrystalline transparent conductive films such as ITO, indium zinc composite oxide, titanium oxide, tin oxide It is desirable to use it as a transparent electrode formed on the substrate (1).

  When used in a simple matrix drive display, it is desirable to provide a metal bus line made of a low resistance metal such as Cu or Al in contact with the transparent electrode line to further reduce the resistance. In addition, a semitransparent electrode obtained by thinly depositing gold or platinum, a semitransparent electrode coated with a polymer such as polyaniline, polypyrrole, or polythiophene can be used.

  However, in other cases, the anode (2) may be opaque. In that case, a metal plate made of gold, platinum, palladium, nickel or the like having a large work function value that facilitates hole injection into the organic light emitting layer (4) through the organic hole injection transport layer (3) in the anode (2) The cathode (5) is transparent using a semiconductor substrate such as silicon, gallium phosphide, amorphous silicon carbide or the like having a work function of 4.6 eV or more, or a substrate in which such a metal or semiconductor is coated on an insulating substrate (1). An electrode or a translucent electrode is used. If the cathode (5) is also opaque, at least one end of the organic light emitting layer (4) needs to be transparent.

  Next, an organic hole injection transport layer (3) is formed on the anode (2). In the present invention, as a hole transporting material, a tertiary amine compound containing one or more triarylamine structures and a para amine on at least two aryl groups is hydrogen and a carbonyl compound A hole transporting condensation compound obtained by addition condensation is used.

  The specific structure of the tertiary amine compound used in the present invention, which contains one or more triarylamine skeletons and in which the para position on at least two aryl groups is hydrogen, is represented by the following chemical formulas (1) to (4). Hole transporting material of the following formula, blue hole transporting light emitting material of the following chemical formula (5), green hole transporting light emitting material of the following chemical formula (6), red hole transporting light emitting of the following chemical formulas (7) to (8) Illustrated with materials.

（式中、Ｒ_１はフェニル基上の水素原子またはメチル基、エチル基、イソプロピル基、ｔ−ブチル基等のアルキル基、メトキシ基等のアルコキシ基、トリル基等のアリール基、−Ｎ_２ ^＋Ｃｌ⁻等のジアゾニウム塩基、−Ｎ_３、−ＳＯ_２Ｎ_３、−ＣＯＮ_３から独立に選ばれる。）

Wherein R ₁ is a hydrogen atom on the phenyl group or an alkyl group such as a methyl group, an ethyl group, an isopropyl group or a t-butyl group, an alkoxy group such as a methoxy group, an aryl group such as a tolyl group, -N ₂ ⁺ Cl ^- or the like of the diazonium _{base, -N 3, -SO 2 N 3} , are independently selected from -CON _3).

上記化学式（２）〜（３）で示される第３級アミン化合物においてＲ_１はフェニル基上の水素原子またはメチル基、エチル基、イソプロピル基、ｔ−ブチル基等のアルキル基、メトキシ基等のアルコキシ基、ハロゲン原子、トリル基等のアリール基から独立に選ばれ、かつ、分子中少なくとも２カ所以上のフェニル基のパラ位は水素原子である。ｎは繰り返しを表す０から２の整数である。

In the tertiary amine compounds represented by the chemical formulas (2) to (3), R ₁ is a hydrogen atom on the phenyl group or an alkyl group such as a methyl group, an ethyl group, an isopropyl group, or a t-butyl group, a methoxy group, or the like. It is independently selected from aryl groups such as an alkoxy group, a halogen atom, and a tolyl group, and at least two phenyl groups in the molecule are para-positioned in a hydrogen atom. n is an integer of 0 to 2 representing repetition.

（式中、Ｒ_１はフェニル基上の水素原子またはメチル基、エチル基、イソプロピル基、ｔ−ブチル基等のアルキル基、メトキシ基等のアルコキシ基、トリル基等のアリール基から独立に選ばれ、かつ、分子中少なくとも２カ所以上のフェニル基のパラ位は水素原子である。）

Wherein R ₁ is independently selected from a hydrogen atom on a phenyl group or an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a t-butyl group, an alkoxy group such as a methoxy group, and an aryl group such as a tolyl group. In addition, the para positions of at least two phenyl groups in the molecule are hydrogen atoms.)

上記化学式（５）〜（８）で示される第３級アミン化合物においてＲ_１はメチル基、エチル基、イソプロピル基、ｔ−ブチル基等のアルキル基、メトキシ基等のアルコキシ基、ハロゲン原子、トリル基等のアリール基から独立に選ばれる。

In the tertiary amine compounds represented by the chemical formulas (5) to (8), R ₁ is an alkyl group such as a methyl group, an ethyl group, an isopropyl group or a t-butyl group, an alkoxy group such as a methoxy group, a halogen atom, or tolyl. It is independently selected from an aryl group such as a group.

  The carbonyl compound used as a raw material of the hole transportable condensate of the present invention is exemplified by chemical formulas 9-15.

（ここで、Ｒは水素原子、またはメチル基、エチル基、イソプロピル基、ｎ−ブチル基、ｔ−ブチル基等のアルキル基、塩素原子等のハロゲン、ジメチルアミノ基、ジエチルアミノ基から選ばれる。ｎは１または２の整数）

(Here, R is selected from a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, an isopropyl group, an n-butyl group and a t-butyl group, a halogen such as a chlorine atom, a dimethylamino group and a diethylamino group. Is an integer of 1 or 2)

上記化学式（９）〜（１２）で示されるカルボニル化合物において、Ｒは水素原子、またはメチル基、エチル基、イソプロピル基、ｎ−ブチル基、ｔ−ブチル基等のアルキル基、塩素原子等のハロゲン、ジメチルアミノ基、ジエチルアミノ基から選ばれる。

In the carbonyl compounds represented by the above chemical formulas (9) to (12), R represents a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, an isopropyl group, an n-butyl group, or a t-butyl group, or a halogen such as a chlorine atom. , A dimethylamino group, and a diethylamino group.

および、化学式（１５）で表される化合物

And a compound represented by the chemical formula (15)

（ここで、Ｒ_１、Ｒ_２は水素原子、またはメチル基、エチル基、イソプロピル基、ｎ−ブチル基等のアルキル基、その他、「機能性高分子シリーズ、感光性高分子（講談社１９７７年刊）」の１５５〜１５６ページ表６．１の感光基を含む基から独立に選ばれる）
以上に例示した第３級アミン化合物とカルボニル化合物との付加縮合は、１，４−ジオキサン等の有機溶媒中で、パラ−トルエンスルホン酸等の酸を触媒として用い、５０℃〜１５０℃程度の温度で１０分〜２４時間程度反応させ行う。この際、第３級アミン化合物のカルボニル化合物と反応する確率が高いフェニル基上のパラ位の水素が２カ所以上未置換である化合物を用いる。

(Here, R ₁ and R ₂ are hydrogen atoms or alkyl groups such as methyl, ethyl, isopropyl and n-butyl groups, etc., “Functional Polymer Series, Photosensitive Polymer (Kodansha 1977) ”On page 155 to 156, independently selected from groups including photosensitive groups in Table 6.1)
The addition condensation of the tertiary amine compound and the carbonyl compound exemplified above is carried out using an acid such as para-toluenesulfonic acid as a catalyst in an organic solvent such as 1,4-dioxane. The reaction is carried out at a temperature for about 10 minutes to 24 hours. At this time, a compound in which two or more hydrogens at the para position on the phenyl group which are highly likely to react with the carbonyl compound of the tertiary amine compound are unsubstituted is used.

  Specific examples of the hole transporting condensate obtained are shown below.

上記化学式（１６）〜（１９）で示される本発明の付加縮合物において、ｎは重合度を表す正の整数を示し、Ｒ_１は水素原子または置換基を表し、置換基はメチル基、エチル基、イソプロピル基、ｔ−ブチル基等のアルキル基、メトキシ基等のアルコキシ基、トリル基等のアリール基、−Ｎ_２ ^＋Ｃｌ⁻等のジアゾニウム塩基、−Ｎ_３、−ＳＯ_２Ｎ_３、−ＣＯＮ_３から選ばれる。

In the addition condensate of the present invention represented by the chemical formulas (16) to (19), n represents a positive integer representing the degree of polymerization, R ₁ represents a hydrogen atom or a substituent, and the substituent is a methyl group, ethyl group, an isopropyl group, an alkyl group of a t- butyl group and the like, an alkoxy group such as methoxy group, aryl groups such as _tolyl, ^-N 2 + Cl ^- or the like of the diazonium _{base, -N 3, -SO 2 N 3} , - Selected from CON ₃ .

  The molecular weight of the resulting addition condensate is about 3,000 to 1,000,000 as the number average molecular weight (converted to Showa Denko standard polystyrene) determined by the GPC method using styrene gel as a fixed layer phase and chloroform as a mobile phase. More preferably, the component of 10,000 to 1,000,000 is fractionated by excluding low molecular weight components by reprecipitation, dialysis, centrifugation, or the like. Moreover, the terminal of the molecular chain may have an OH group derived from a carbonyl compound such as a methylol group.

  In order to be soluble and have a molecular weight distribution on the high molecular weight side, two hydrogens at the para position on the phenyl group on the triarylamine skeleton are left in place so that they do not gel when reacted for a long time, and other phenyl groups A bifunctional tertiary amine compound in which the hydrogen at the para position is substituted with an alkyl group such as a methyl group, an ethyl group, an isopropyl group, or a t-butyl group, an alkoxy group such as a methoxy group, or an aryl group such as a tolyl group. It is sufficient to use it and react with an exactly equivalent carbonyl compound.

  When there are three or more para-positioned hydrogens on the phenyl group on the triarylamine skeleton, a component having a three-dimensional cross-linking structure is also included, and the gel may be formed by a long-time reaction.

  These hole-transporting condensation compounds of the present invention have a triarylamine compound in the main chain skeleton, have high hole-transporting performance, and are a polymer, so that their glass transition temperature is higher than that of low-molecular compounds. The heat resistance of the element can be increased. Specifically, in the chemical formulas (16) to (19), when R is a hydrogen atom, Tg is 148 ° C., 141 ° C., 190 ° C., 157 ° C. Measured).

  A thin film can be easily formed by dissolving in an organic solvent such as toluene or chloroform and using a wet method such as a spin coat method or a blade coat method.

  Further, in the hole transporting condensate layer of the present invention, the step of the work function value between the anode and the light emitting layer is reduced to improve the hole injection efficiency, improve the adhesion between layers, prevent deterioration, adjust the color tone, etc. Other known aromatic tertiary amine materials, metal phthalocyanines such as CuPc, chlorinated copper phthalocyanine, and tetra (t-butyl) copper phthalocyanine, metal phthalocyanines such as quinacridone, and low molecular weight compounds such as quinacridone A hole injection / transport material or a polymer hole transport material such as poly (para-phenylene vinylene) or polyaniline is mixed with a compound represented by (Chemical Formula 1) and used as a hole injection / transport layer, or shown in FIG. As described above, the hole transporting material insoluble in the solvent at the time of film formation is the first hole injection transport layer (11) and the second hole injection transport layer (12). Hole transportability according to the present invention Compound a may be formed positive hole injection transport layer of the multilayer with. Further, it is possible to form a multilayer hole transport layer of three or more layers. The hole transport condensate layer of the present invention can crosslink molecular chains in order to increase heat resistance and insolubilize in an organic solvent.

  Specifically, a photosensitive group such as an azide group, a sulfonyl azide group, or a carbonyl azide group is introduced into a substituent in the tertiary amine compound, or a cinnamyl group, a stilbene group, a vinyl group, or the like in the carbonyl compound. Sensitization of benzophenone or the like by introducing a photo-crosslinkable group, or introducing a group in the tertiary amine compound or carbonyl compound that can easily extract a hydrogen radical such as an ethyl group or an isopropyl group. Add material and photocrosslink.

  Photocrosslinking is performed by irradiating with ultraviolet rays in a vacuum or in an inert gas such as argon while heating to Tg or higher.

  In order to perform sufficient crosslinking, it is also possible to perform crosslinking with formaldehyde gas in an acid gas atmosphere such as hydrochloric acid or formic acid after film formation and photocrosslinking.

  The hole transporting condensate of the present invention is a single or mixed hole transporting light emitting material having a fluorescence spectrum peak in the visible light region such as chemical formulas (5) to (8) in the tertiary amine used as a raw material. Or by mixing with a hole transport material as represented by chemical formulas (1) to (4), it functions as an organic hole transport light-emitting layer (6), and can be arbitrarily selected from blue, green, red, white, etc. Can be obtained.

  When forming the pattern of the hole-transporting condensate of the present invention, a desired negative pattern can be formed by developing with an organic solvent such as toluene after film formation and mask exposure.

  In addition, a negative pattern can be obtained by introducing a diazonium salt into a substituent in the tertiary amine compound, forming a film, exposing to a mask, and developing with an alkaline aqueous solution. As shown in FIG. 5, the patterning of the hole-transporting condensate of the present invention having blue, green and red fluorescence is repeated three times to arrange the blue, green and red patterns in two dimensions on the substrate. Pattern-formed hole transport light emitting layer (13) corresponding to a color display can be obtained.

  The film thickness of the organic hole injecting and transporting layer (3) and the organic hole transporting and emitting layer (6) is 100 nm or less, preferably 5 to 70 nm, even when formed by a single layer or a laminate.

  Next, the case where the organic light emitting layer (4) is formed on the organic hole injecting and transporting layer (3) or the second hole injecting and transporting layer (12) as shown in FIGS. 1 and 3 will be described.

  The organic light emitting layer (4) is a layer containing one or more arbitrary phosphors having strong fluorescence in the visible region. If the organic light emitting layer (4) has a strong fluorescence in the solid state and a smooth film can be formed, the fluorescence is good. The organic light-emitting layer (4) can be formed only by the body, but when the fluorescence is quenched or a smooth film cannot be formed in the solid state, it can be formed in a hole injection transport material, an electron injection transport material, or an appropriate resin. It can be used by being dispersed in an appropriate concentration in a binder.

  Examples of phosphors that can be used in the EL device of the present invention include 9,10-diarylanthracene derivatives, salicylates, pyrenes, coronene, perylene, rubrene, tetraphenylbutadiene, 9,10-bis (phenylethynyl) anthracene. 8-quinolinolato lithium, Alq, tris (5,7-dichloro-8-quinolinolato) aluminum complex, tris (5-chloro-8-quinolinolato) aluminum complex, bis (8-quinolinolato) zinc complex, tris (5 -Fluoro-8-quinolinolato) aluminum complex, tris (4-methyl-5-trifluoromethyl-8-quinolinolato) aluminum complex, tris (4-methyl-5-cyano-8-quinolinolato) aluminum complex, bis (2-methyl-5-trifluoro) Mechi -8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, tris (8-quinolinolato) scandium complex, Bis [8- (paratosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, poly-2,5-diheptyloxy-para-phenylene vinylene, or JP-A-4-31488 of Idemitsu Kosan application, U.S. Pat. Nos. 5,141,671 and 4,769,292 of Eastman Kodak Company, and N, N 'Diaryl substituted pyrrolopyrrole compounds etc. It is below.

  These organic light emitting layer materials can be formed by coating by a vacuum deposition method, spin coating, blade coating or the like.

  The film thickness of the organic light emitting layer (4) is 100 nm or less, preferably 5 to 70 nm, even when formed by a single layer or stacked layers.

  Further, the phosphor in the organic light emitting layer (4) is described in a laser die catalog of US Lambda Fizzic or Eastman Kodak for the purpose of light emission wavelength conversion, light emission wavelength expansion, light emission efficiency improvement, and the like. One or more types of phosphors such as coumarin, quinacridone, perylene, and pyran may be doped into the host luminescent matrix as a guest luminescent material, or two or more luminescent layers may be stacked. One of them may exhibit fluorescence in the infrared region or the ultraviolet region. Furthermore, the phosphor of the light emitting layer may be an inorganic substance.

  Next, when the organic electron injecting and transporting layer (7) is laminated on the organic light emitting layer (4) or the organic hole transporting light emitting layer (6) as shown in FIGS. Preferred conditions for the material are high electron mobility, high LUMO density of states, and the LUMO energy level is between the LUMO energy level of the organic light emitting layer material and the Fermi level (work function) of the cathode material. The ionization energy is larger than that of the organic light emitting layer material, and the film formability is good. Further, in an element in which the anode (2) is opaque and light is extracted from the transparent or translucent cathode (5), it is necessary to be substantially transparent at least in the fluorescence wavelength region of the organic light emitting layer material.

  Examples of the organic electron injecting and transporting layer include BPBD, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, and an oxadiazole derivative synthesized by Hamada et al. (The Chemical Society of Japan, page 1540). 1991) and bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, triazole compounds described in JP-A-7-90260, and Marko Strukelj et al. Described in Science 267, 1969 (1995). , Dehydrofluorination condensation polymer of 1,2-Bis (3-hydroxy) phenyl-4- (3-trifluoromethylphenyl) -triazole and Decafluorophenyl, etc. provided on the light emitting layer of Poly (p-phenylenevinylene) Examples thereof include inorganic semiconductors such as compounds, silicon carbide, and amorphous silicon films, and photoconductive films. In addition, in the case where a light emitting layer is formed by doping a guest light emitting matrix in the host light emitting matrix, the host light emitting matrix can be used as an organic electron injecting and transporting layer.

  The organic electron injecting and transporting layer (7) is formed by a method such as spin coating or by a method such as a vacuum deposition method, a CVD method or a cumulative film method, and a single layer having a thickness of 1 nm to 1 μm. Alternatively, the film is formed in multiple layers.

  Next, the cathode (5) is formed on the organic light emitting layer (4) or the organic electron injecting and transporting layer (7). The cathode is more effective when a material having a low work function is used on the surface in contact with the organic light emitting layer (4) or the organic electron injecting and transporting layer (7) in order to effectively inject electrons. The material constituting the cathode is a single metal such as Mg, Al, Yb or the like, or a low work function such as Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, An alloy system or a laminated system of one or more metals such as Y and Yb and a stable metal element such as Ag, Al, In, Sn, Zn, Mn, Ti, and Zr is used.

  Depending on the material, the cathode can be formed by resistance heating vapor deposition, electron beam vapor deposition, reactive vapor deposition, ion plating, or by sputtering using an alloy target. . The cathode is formed with a thickness of about 10 nm to 1 μm.

Next, a sealing layer (8) is formed on the element in order to prevent oxidation of the layer made of organic matter and the electrode of the element. The sealing layer (8) is formed immediately after the formation of the cathode (5). Examples of the sealing layer material include oxides such as SiO ₂ , SiO, GeO, MgO, CaO, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZnO, and SnO (one oxide has a slightly stoichiometric ratio). Oxygen gas such as MgF ₂ , LiF, BaF ₂ , AlF ₃ , sulfides such as ZnS, and inorganic compounds having a high water vapor barrier property, but are limited to the above examples. Is not to be done. These are formed into a single layer, a composite layer, or a multilayered layer by vapor deposition, reactive vapor deposition, CVD, sputtering, ion plating, or the like.

  Furthermore, in order to prevent moisture from entering, the EL element substrate is hermetically sealed in a vacuum, or a commercially available low-humidity photocurable adhesive, epoxy adhesive, silicone adhesive, cross-linked ethylene-vinyl acetate. The periphery or the entire surface of the sealing plate (10) such as a glass plate is adhered and sealed using an adhesive resin such as a copolymer adhesive sheet or an adhesive material (9) such as low-melting glass. Besides a glass plate, a metal plate, a plastic plate, etc. can also be used. A desiccant such as silica gel or zeolite may be mixed in the adhesive material (9), or a desiccant such as silica gel, zeolite or calcia on the sealing layer (8) or on the inner surface of the sealing plate (10). Alternatively, a getter layer made of alkali metal, alkaline earth metal, rare earth, or the like may be formed.

  The organic thin-film EL device configured as described above emits light when the organic hole injecting and transporting layer (3) side is positive and connected to a power source (14) with a lead wire (15) and a DC voltage is applied. Even when a voltage is applied, the anode (2) emits light while a positive voltage is applied.

In a nitrogen atmosphere, 10 ml of 1,4-dioxane was added to 10.0 g of triphenylamine and 5.42 g of cinnamoyl aldehyde, 0.75 g of paratoluenesulfonic acid was added thereto, and the temperature of the oil bath was 120 ° C. for 15 hours. The reaction was stirred. This was put into methanol and precipitated. When this polymer is purified by reprecipitation with chloroform / methanol = 2/1 and chloroform / acetone = 3/1 to remove low molecular weight substances, hole transport in the form of light yellowish green powder represented by chemical formula (18), R ₁ = H 13.4 g of a functional condensate was obtained.

  About this hole transportable condensate, using 880-PU manufactured by JASCO Corporation as a pump, using a differential refractometer 830-RI manufactured by JASCO Corporation as a detector, moving styrene gel as a stationary phase and moving chloroform. When the GPC measurement was performed as a phase, the number average molecular weight was 10,000 and the weight average molecular weight was 510,000 (standard polystyrene conversion by Showa Denko KK).

  Next, about this hole transportable condensate, when a glass transition point (Tg) was determined at a heating rate of 10 ° C./min in a nitrogen atmosphere using DSC220 manufactured by Seiko Electronics Industry Co., Ltd., 185 ° C. to 187 ° C. Met. The ionization energy measured with a surface analyzer AC-1 manufactured by Riken Keiki Co., Ltd. was 5.8 eV.

  A blue glass plate having a thickness of 1.1 mm was used as the transparent insulating substrate (1), and 120 nm of ITO was coated thereon by a sputtering method to form an anode (2). This transparent conductive substrate was sufficiently washed by water and plasma before use.

The hole injecting and transporting layer is prepared by first vacuum depositing Aldrich copper phthalocyanine as a first hole injecting and transporting layer (11) to a thickness of 10 nm and using the second hole injecting and transporting layer (12) as a hole transporting condensation of the present invention. A toluene solution of the product [Chemical Formula (18), R ₁ = H] was spin-coated to form a thickness of 40 nm.

  Next, 50 nm of Alq was vapor-deposited as an organic light emitting layer (4), and Mg and Ag were vapor-deposited as a cathode (5) on the upper surface thereof at a vapor deposition rate ratio of 10: 1. Finally, GeO was plated by 1 μm as a sealing layer (8), and then the glass plate (10) was adhered and sealed with a photocurable resin (9).

This device stably emitted green light by a DC voltage of 4 V or higher, the luminance at 15 V was 7766 cd / m ² , and the current density was 471 mA / cm ² . Light was emitted in the same manner after heating to 100 ° C.

  After spin-coating the hole transporting condensate of Example 2, the substrate was heated at 250 ° C. in a vacuum at a distance of about 30 cm from a distance of about 30 cm using a 150 W deuterium lamp [L1835 manufactured by Hamamatsu Photonics Co., Ltd.]. It was irradiated for 20 minutes for crosslinking. The membrane was insoluble in toluene. Thereafter, an EL element was produced in the same manner as in Example 2.

This device stably emitted green light by a DC voltage of 4 V or higher, the luminance at 14 V was 8543 cd / m ² , and the current density was 678 mA / cm ² .

After vapor deposition of copper phthalocyanine in the same manner as in Example 2, the hole transporting condensate of Example 1 was spin-coated at 90 nm, then exposed to UV mask under heating at 250 ° C., and line / space (1 mm / 1 mm) stripes by toluene development. A pattern was formed. Further, a hole transporting condensate obtained by reacting in the same manner as in Example 1 using a triphenylamine containing 30% of a green phosphor [chemical formula (6) R ₁ = methoxy] as a raw material was spin-coated to a thickness of 90 nm. A pattern was formed in a stripe pattern in the space portion of the pattern comprising the hole transporting condensate of Example 1 by UV mask exposure under heating at 250 ° C. and toluene development.

  On the upper surface, Mg and Ag were deposited as a cathode (5) at a deposition rate ratio of 10: 1 to 220 nm. Finally, GeO was plated by 1 μm as a sealing layer (8), and then the glass plate (10) was adhered and sealed with a photocurable resin (9).

  This device stably emitted green light in a stripe shape even when heated to 150 ° C.

It is explanatory drawing which shows one Example of the EL element of this invention. It is explanatory drawing which shows one Example of the EL element of this invention. It is explanatory drawing which shows one Example of the EL element of this invention. It is explanatory drawing which shows one Example of the EL element of this invention. It is explanatory drawing which shows one Example of the EL element of this invention.

Explanation of symbols

(1) ... Substrate (2) ... Anode (3) ... Organic hole injection / transport layer (4) ... Organic light emitting layer (5) ... Cathode (6) ... Organic hole transport light emitting layer (7) ... Organic electron injection / transport Layer (8) ... Sealing layer (9) ... Adhesive material layer (10) ... Glass plate (11) ... First hole injection / transport layer (12) ... Second hole injection / transport layer (13) ... Pattern formation Hole transporting light emitting layer (14) ... power source (15) ... lead wire (16) ... cathode outlet

Claims (5)

A hole-transporting condensate obtained by addition condensation of a tertiary amine compound containing at least one triarylamine structure and having at least two aryl groups each having a para-position of hydrogen and a carbonyl compound An EL device comprising a layer containing the organic compound , wherein the tertiary amine compound is selected from any of the following compounds (1) to (6) .

(R1 is a functional group independently selected from a hydrogen atom, an alkyl group such as a methyl group on a phenyl group, an ethyl group, an isopropyl group and a t-butyl group, an alkoxy group such as a methoxy group, and an aryl such as a tolyl group. R1 is a hydrogen atom in the para position of at least two phenyl groups in the molecule, and at least one of R1 is a functional group having an azide group, a sulfonyl azide group, or a carbonyl azide group introduced. N is an integer from 0 to 2 representing repetition.   The EL device according to claim 1, wherein the carbonyl compound has a bridging group containing one or more carbon-carbon double bonds.   2. The EL device according to claim 1, wherein the layer containing the hole transporting condensate is crosslinked.   4. The EL device according to claim 3, wherein the layer containing the hole transporting condensate is patterned by exposure and development.   The EL device according to claim 3, wherein the layer containing the hole transporting condensate contains an organic light emitting material having fluorescence in the visible region.

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