JP4569526B2 - Materials for electroluminescent elements - Google Patents

Description

  The present invention relates to an electroluminescent device having an organic thin film layer including at least an organic light emitting layer between a hole injection electrode and an electron injection electrode.

  In recent years, with the diversification of information equipment, there is an increasing need for a flat display element that consumes less power than a cathode ray tube (CRT). As such flat display elements, there are liquid crystal, plasma display (PDP) and the like. Recently, however, an electroluminescent element of a self-luminous type, a clear display and a wide viewing angle has attracted attention. Here, the electroluminescent element can be roughly classified into an inorganic electroluminescent element and an organic electroluminescent element depending on the constituent materials, and the inorganic electroluminescent element has already been put into practical use and is commercially available as a commercial product.

  However, the driving voltage of the inorganic electroluminescent element is so-called collision-type excitation light emission in which accelerated electrons collide with the light emission center to emit light when a high electric field is applied. Therefore, it is necessary to drive with a high voltage of 100 V or more. There is. For this reason, there has been a problem of incurring higher costs for peripheral devices. There is also a problem that full color display cannot be performed because there is no illuminant that emits blue light.

  On the other hand, in the organic electroluminescent element, charges (holes and electrons) injected from the electrodes recombine in the luminescent material to generate excitons, which excite molecules of the luminescent material to emit light. Since it is so-called injection type light emission, it can be driven at a low voltage. And since it is an organic compound, the molecular structure of a luminescent material can be changed easily and arbitrary luminescent colors can be obtained. Therefore, the organic electroluminescent element is very promising as a display element in the future.

  Here, an organic electroluminescent device having two layers of a hole transport layer and an electron transport light emitting layer was proposed by Tang and VanSlyke (CWTang and SAVanSlyke; Appl. Phys. Lett., 51 ( 1987) 913). The device was composed of a cathode, a hole transport layer, an electron transporting light emitting layer, and a cathode formed on a glass substrate.

  In the above element, the hole transport layer functions to inject holes from the anode to the electron transporting light emitting layer, and prevents electrons injected from the cathode from escaping to the anode without recombining with the holes. It also plays a role of containing electrons in the transporting light emitting layer. For this reason, due to the electron confinement effect by the hole transport layer, recombination of electrons and holes occurs more efficiently than the conventional single layer structure device, and the driving voltage can be greatly reduced.

  Saito et al. Also showed that not only the electron transport layer but also the hole transport layer can be a light-emitting layer in a two-layer device (C. Adachi, T. Tsutsui and S. Saito; Appl. Phys. Lett., 55 (1989) 1489).

  Saito et al. Proposed an organic electroluminescent device with a three-layer structure in which an organic light emitting layer is sandwiched between a hole transport layer and an electron transport layer (C. Adachi, S. Tokito, T. Tsutsui). and S. Saito; Jpn. J. Appl. Phys., 27 (1988) L269). This consists of an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode formed on a glass substrate. The hole transport layer functions to contain electrons in the light emitting layer, and the electron transport layer contains holes. Luminous efficiency is further improved because it functions to be contained in the light emitting layer.

As described above, in order to improve the light emission efficiency of the organic electroluminescence device, the layer structure has been improved. However, the present situation is that it is necessary to increase the luminance and the efficiency of the light emission.
In addition, in order for the organic electroluminescence device to emit light for a long time, it is necessary to emit light at a lower voltage and a lower current density.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an electroluminescent element excellent in durability that emits light with high luminance and high efficiency.

  That is, the present invention provides a light-emitting layer or a plurality of organic compound thin layers including a light-emitting layer between a pair of electrodes, and at least one layer contains a polymer amino compound represented by the following general formula (I) An electroluminescent device characterized by that;

（式中、Ａr_１およびＡr_３は、それぞれ独立して、置換基を有してもよいアリーレン基を表わし、Ａｒ_１およびＡｒ_３はそれぞれ結合基を介して結合していてもよい；Ａr_２およびＡr_４は、それぞれ独立して、置換基を有してもよいアリール基または複素環基を表わす；ｌは０〜２の整数を表す；ｍは０〜２の整数を表す；ｎは自然数を表す）に関する。

(In the formula, Ar ₁ and Ar ₃ each independently represent an arylene group which may have a substituent, and Ar ₁ and Ar ₃ may each be bonded via a bonding group; Ar ₂ And Ar ₄ each independently represents an aryl group or heterocyclic group which may have a substituent; l represents an integer of 0 to 2; m represents an integer of 0 to 2; n represents a natural number Represents).

The specific polymer amino compound represented by the general formula (I) is a good hole injection transport material or organic light emitting material.
This is presumably because the polymer amino compound represented by the general formula (I) has a high hole transport property and a high quantum yield of fluorescence in a solid.

In the general formula (I), Ar ₁ and Ar ₃ each independently represent an arylene group such as phenylene and diphenylene. These groups may have a substituent such as a lower alkyl group or a lower alkoxy group. Ar ₁ and Ar ₃ may be bonded via a bonding group. What is a linking group?

などの２価の基であり、Ａｒ_１あるいはＡｒ_３が結合基を介して結合するとは、例えば結合基が−Ｏ−や−Ｓ−であると

A divalent group such as Ar ₁ or Ar ₃ bonded via a linking group is, for example, that the linking group is —O— or —S—.

のように結合している状態をいう。

It means the state of being connected like.

Preferred Ar ₁ and Ar ₃ are

である。

It is.

Ar ₂ and Ar ₄ each independently represents an aryl group which may have a substituent, such as phenyl, diphenyl and the like, or a heterocyclic group such as thienyl, furyl and the like. These groups may have a substituent such as a lower alkyl group or a lower alkoxy group.

Preferred Ar ₂ and Ar ₄ are a phenyl group having a phenyl group and a lower alkyl group or a lower alkoxy group as a substituent.

  l represents an integer of 0 to 2, preferably 0 to 1. m represents an integer of 0 to 2, preferably 0 to 1. However, l and m are not 0 at the same time. n is a natural number, and the value is not particularly limited, but may be, for example, 5 to 1000, preferably 10 to 1000.

  Specific examples of the polymer amino compound represented by the general formula (I) used in the present invention include the following, but these examples are not intended to limit the scope of the present invention. Absent.

  The polymeric amino compound represented by the general formula (I) can be produced by a known method described in Makromol. Chem. 193, p. 909 (1992), for example, the following amino compound and halogen compound;

または、下記アミノ化合物とハロゲン化合物；

Or the following amino compounds and halogen compounds;

とを、塩基性化合物または遷移金属化合物触媒、溶媒の存在下、Ｕｌｌｍａｎｎ反応により合成することができる。

Can be synthesized by the Ullmann reaction in the presence of a basic compound or a transition metal compound catalyst and a solvent.

  As basic compounds used for synthesis, alkali metal hydroxides, carbonates, hydrogen carbonates, alcoholates, etc. are generally used, but quaternary ammonium compounds, aliphatic amines, aromatic amines and the like are used. It is also possible to use organic bases. Of these, alkali metals and quaternary ammonium carbonates and hydrogen carbonates are preferably used. Further, alkali metal carbonates and hydrogen carbonates are most preferred from the viewpoints of reaction rate and thermal stability.

Examples of the transition metal or transition metal compound used in the synthesis include metals such as Cu, Fe; Co, Ni, Cr, V, Pd, Pt, and Ag, and their compounds. Palladium and their compounds are preferred. The copper compound is not particularly limited, and most copper compounds are used, but cuprous iodide, cuprous chloride, cuprous oxide, cuprous bromide, cuprous cyanide, cuprous sulfate , Cupric sulfate, cupric chloride, cupric hydroxide, cupric oxide, cupric bromide, cupric phosphate, cuprous nitrate, cupric nitrate, copper carbonate, first acetic acid Copper, cupric acetate and the like are preferable. In particular CuCl Among _{them, CuCl 2, CuBr, CuBr 2} , CuI, CuO, Cu 2 O, CuSO 4, Cu (OCOCH 3) 2 is preferred in that it is readily available. As the palladium compound, halides, sulfates, nitrates, organic acid salts and the like can be used. The amount of the transition metal and its compound used is 0.5 to 500 mol% of the halogen compound to be reacted.

  The solvent used in the synthesis may be any commonly used solvent, but an aprotic polar solvent such as nitrobenzene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone is preferably used.

  The synthesis reaction is generally performed at a temperature of 100 to 250 ° C. under normal pressure, but may be performed under pressure. After completion of the reaction, the solid matter precipitated in the reaction solution is removed, and then the solvent is removed to obtain the product.

  1 to 4 schematically show possible configurations of the electroluminescent device of the present invention. In FIG. 1, (1) is an anode, on which a hole injection transport layer (2), an organic light emitting layer (3), and a cathode (4) are sequentially laminated. The injecting and transporting layer contains a polymer amino compound represented by the above general formula (I).

  In FIG. 2, (1) is an anode, on which a hole injecting and transporting layer (2), an organic light emitting layer (3), an electron injecting and transporting layer (5) and a cathode (4) are sequentially laminated. The high-molecular amino compound represented by the above general formula (I) is contained in the hole injecting and transporting layer.

  In FIG. 3, (1) is an anode, on which an organic light emitting layer (3), an electron injecting and transporting layer (5), and a cathode (4) are sequentially laminated. Contains a high molecular amino compound represented by the above general formula (I).

  In FIG. 4, (1) is an anode, and an organic light emitting layer (3) and a cathode (4) are sequentially laminated thereon, and the organic light emitting material (6) and A charge transport material (7) is contained, and a polymer amino compound represented by the above general formula is used for the organic light emitting material or the charge transport material.

  In the electroluminescent element having the above structure, the anode (1) and the cathode (4) are connected by the lead wire (8), and the organic light emitting layer (3) emits light by applying a voltage to the anode (1) and the cathode (4). To do.

The specific polymer amino compound represented by the general formula (I) is a good hole injection transport material or organic light emitting material.
This is considered to be because a specific polymer amino compound has high hole transportability and a high quantum yield of fluorescence in a solid.

  As the conductive material used as the anode (1) of the electroluminescent element, one having a work function larger than 4 eV is preferable, and carbon, aluminum, vanadium, iron, cobalt, nickel, copper, zinc, tungsten, silver, tin , Gold and their alloys, and conductive metal compounds such as tin oxide, indium oxide, antimony oxide, zinc oxide and zirconium oxide are used.

  The metal forming the cathode (4) is preferably one having a work function smaller than 4 eV, and magnesium, calcium, titanium, yttrium lithium, gadolinium, ytterbium, ruthenium, manganese, and alloys thereof are used.

  In the electroluminescent element, at least the anode (1) or the cathode (4) needs to be a transparent electrode so that light emission can be seen. At this time, if a transparent electrode is used for the cathode, the transparency is likely to be impaired. Therefore, the anode is preferably a transparent electrode.

  When forming a transparent electrode, a conductive material such as that described above is used on a transparent substrate, and a desired method using a means such as vapor deposition, sputtering, or a sol-gel method or a method of dispersing and applying to a resin or the like. What is necessary is just to form so that translucency and electroconductivity may be ensured.

  The transparent substrate is not particularly limited as long as it has an appropriate strength, is not adversely affected by heat due to vapor deposition or the like, and is transparent if an electroluminescent element is produced. It is also possible to use resins such as polyethylene, polypropylene, polyethersulfone, polyetheretherketone and the like. Commercial products such as ITO and NESA are known as transparent electrodes formed on a glass substrate, but these may be used.

  An example of manufacturing an electroluminescent element having the configuration shown in FIG. 2 using the above electrode will be described.

  First, a hole injection transport layer (2) is formed on the anode (1) described above. The hole injecting and transporting layer (2) can be formed by dip-coating or spin-coating a solution in which the polymer amino compound represented by the general formula (I) is dissolved or an appropriate resin. The thickness is usually 5 to 1000 nm, preferably about 10 to 500 nm.

  The thicker the film is formed, the higher the applied voltage for emitting light, and the lower the light emission efficiency, which tends to cause deterioration of the electroluminescent element. Further, when the film thickness is reduced, the light emission efficiency is improved, but breakdown is easily caused and the life of the electroluminescent element is shortened.

  The polymeric amino compound of the general formula (I) may be used in combination with other charge transport materials, and as such charge transport materials, it has an excellent hole injection effect for the light emitting layer or the light emitting material, and has high mobility. Thus, a compound that prevents the excitons generated in the light emitting layer from moving to the electron injection layer or the electron transport material and has an excellent thin film forming ability can be given.

  Specifically, phthalocyanine compound, naphthalocyanine compound, porphyrin compound, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acyl hydrazone, polyarylalkane, Examples include, but are not limited to, stilbene, butadiene, benzidine type triarylamine, diamine type triarylamine, and their derivatives, and polymer materials such as polyvinylcarbazole, polysilane, and conductive polymer. .

  As will be described later, when the polymer amino compound represented by the general formula (I) is used as the light emitting material of the organic light emitting layer (3), as the hole transporting material used for the hole injecting and transporting layer, Such as N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-bis (4-Methylphenyl) -1,1′-diphenyl-4,4′-diamine, N, N′-diphenyl-N, N′-bis (1-naphthyl) -1,1′-diphenyl-4,4 '-Diamine, N, N'-diphenyl-N, N'-bis (2-naphthyl) -1,1'-diphenyl-4,4'-diamine, N, N'-tetra (4-methylphenyl)- 1,1′-diphenyl-4,4′-diamine, N, N′-tetra ( -Methylphenyl) -1,1'-bis (3-methylphenyl) -4,4'-diamine, N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'- Bis (3-methylphenyl) -4,4′-diamine, N, N′-bis (N-carbazolyl) -1,1′-diphenyl-4,4′-diamine, 4,4 ′, 4 ″ -tris (N-carbazolyl) triphenylamine, N, N ′, N ″ -triphenyl-N, N ′, N ″ -tris (3-methylphenyl) -1,3,5-tri (4-aminophenyl) benzene 4,4 ′, 4 ″ -tris [N, N ′, N ″ -triphenyl-N, N ′, N ″ -tris (3-methylphenyl)] triphenylamine and the like. These may be used as a mixture of two or more.

  Next, an organic light emitting layer (3) is formed on the hole injection transport layer (2). As an organic light emitting material and a light emitting auxiliary material used for the organic light emitting layer, known materials can be used, for example, epidolidine, 2,5-bis [5,7-di-t-pentyl-2-benzoxazolyl]. Thiophene, 2,2 ′-(1,4-phenylenedivinylene) bisbenzothiazole, 2,2 ′-(4,4′-biphenylene) bisbenzothiazole, 5-methyl-2- {2- [4- ( 5-methyl-2-benzoxazolyl) phenyl] vinyl} benzoxazole, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, perinone 1,4-diphenylbutadiene, tetraphenylbutadiene, coumarin, acridine, stilbene, 2- (4-biphenyl) -6-phen Rubenzoxazole, aluminum trisoxine, magnesium bisoxin, bis (benzo-8-quinolinol) zinc, bis (2-methyl-8-quinolinol) aluminum oxide, indium trisoxine, aluminum tris (5-methyloxin), lithium oxine , Gallium trisoxine, calcium bis (5-chlorooxin), polyzinc-bis (8-hydroxy-5-quinolinolyl) methane, dilithium epindridione, zinc bisoxin, 1,2-phthaloperinone, 1,2-naphthaloperinone And so on.

  In addition, general fluorescent dyes such as fluorescent coumarin dyes, fluorescent perylene dyes, fluorescent pyran dyes, fluorescent thiopyran dyes, fluorescent polymethine dyes, fluorescent mesocyanine dyes, fluorescent imidazole dyes and the like can also be used. Of these, particularly preferred are chelated oxinoid compounds.

  The organic light emitting layer may have a single layer structure of the light emitting material described above, or may have a multilayer structure in order to adjust characteristics such as light emission color and light emission intensity. Two or more kinds of luminescent materials may be mixed or doped in the luminescent layer.

  The organic light emitting layer (3) may be formed by vapor-depositing a light emitting material as described above, or formed by dip coating or spin coating a solution in which the light emitting material is dissolved or a solution dissolved with an appropriate resin. May be.

  In the organic light emitting layer, a polymer amino compound represented by the general formula (I) can also be used as a light emitting substance. The organic light emitting layer may have a single layer structure of a polymer amino compound, or may have a multilayer structure in order to adjust characteristics such as light emission color and light emission intensity. Two or more kinds of luminescent materials may be mixed or doped in the luminescent layer.

  When the light emitting layer is formed using the polymer amino compound represented by the general formula (I), it is formed by dip coating or spin coating a solution in which the polymer amino compound is dissolved or a solution dissolved with an appropriate resin. Can do. The thickness is usually about 5 to 1000 nm, preferably about 10 to 500 nm.

  The thicker the film is formed, the higher the applied voltage for causing light emission, and the lower the light emission efficiency, the more likely the deterioration of the organic electroluminescent device. Further, when the film thickness is reduced, the light emission efficiency is improved, but breakdown is easily caused and the life of the light emitting element is shortened.

  An electron injecting and transporting layer (5) is formed on the organic light emitting layer (3). The electron injecting and transporting material used for the electron injecting and transporting layer has the ability to transport electrons, has an excellent electron injecting effect on the light emitting layer or light emitting material, and has a high electron mobility and hole injecting and transporting material From the above, compounds that prevent the movement of holes and have excellent thin film forming ability can be mentioned.

  For example, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2- (1-naphthyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 1,4-bis {2- [5- (4-tert-butylphenyl) -1,3,4-oxadiazolyl]} benzene, 1,3-bis {2- [5- (4-tert-butylphenyl) -1,3,4-oxadiazolyl]} benzene, 4,4′-bis {2- [5- (4-tert-butylphenyl) -1,3,4- Oxadiazolyl]} biphenyl, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-thiodiazole, 2- (1-naphthyl) -5- (4-tert-butylphenyl) ) -1,3,4-thiodiazole, 1,4-bis {2- [5- (4-tert-butylphenyl) -1,3,4-thiodiazolyl]} benzene, 1,3-bis {2- [5- (4-tert-butylphenyl) -1,3,4-thiodiazolyl]} benzene 4,4′-bis {2- [5- (4-tert-butylphenyl) -1,3,4-thiodiazolyl]} biphenyl, 3- (4-biphenylyl) -4-phenyl-5- (4 -Tert-butylphenyl) -1,2,4-triazole, 3- (1-naphthyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole, 1,4- Bis {3- [4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazolyl]} benzene, 1,3-bis {3- [4-phenyl-5- (4-tert -Butylphenyl) -1,3,4-oxadiazolyl]} benzene, 4,4′-bis {2- [4-phenyl-5- (4-tert-butylphenyl) -1,3,4-oxadiazolyl]} biphenyl, 1,3,5-tris {2- [5- ( 4-tert-butylphenyl) -1,3,4-oxadiazolyl]} benzene and the like. These may be used in combination of two or more. Next, the above-described cathode is formed on the electron injecting and transporting layer.

  The case where the electroluminescent element is formed by sequentially laminating the hole injecting and transporting layer (2), the light emitting layer (3), the electron injecting and transporting layer (5), and the cathode (4) on the anode (1) has been described. However, the light emitting layer (3), the electron injecting and transporting layer (5) and the cathode are sequentially laminated on the anode (1) (FIG. 3), the electron injecting and transporting layer (5) and the organic photosensitive layer on the cathode (4). The layer (3) and the anode (1) are sequentially stacked, or the hole injection / transport layer (2), the light emitting layer (3), and the cathode (4) are sequentially stacked on the anode (1) (FIG. 1). Of course, the electron injecting and transporting layer (5), the light emitting layer (3), the hole injecting and transporting layer (2), and the anode (1) may be sequentially laminated on the cathode (4).

  A pair of transparent electrodes of a cathode and an anode is connected to each electrode by an appropriate lead wire (8) such as a nichrome wire, a gold wire, a copper wire, a platinum wire, and the electroluminescent element has an appropriate voltage (Vs) applied to both electrodes. ) To emit light.

  The electroluminescent element of the present invention can be applied to various display devices or display devices.

  Hereinafter, the present invention will be described with reference to examples. The organic electroluminescent device of the present invention achieves improvement in luminous efficiency, luminous luminance, and long life, and a luminescent substance, a luminescent auxiliary material, a charge transport material, a sensitizer, a resin, It is not limited to the electrode material or the like and the element manufacturing method.

Synthesis Example 1 (Synthesis of Compound (1))
13.0 g (50 mmol) of N, N′-diphenyl-1,4-phenylenediamine was dissolved in 250 ml of dihexyl ether, and 100 mmol of a hexane solution of butyl lithium was slowly added dropwise to the solution. Then, after stirring at 110 ° C. for 2 hours, 16.5 g (50 mmol) of 1,4-diiodobenzene and 0.48 g (25 mmol) of copper iodide were added and reacted at 200 ° C. for 16 hours.

  After cooling, the resulting reaction solution was filtered and extracted three times with boiling tetrahydrofuran. The tetrahydrofuran solution was concentrated and purged with a methanol solution to obtain the desired polymer. This operation was repeated three times.

Synthesis Example 2 (Synthesis of Compound (8))
16.8 g (50 mmol) of N, N′-diphenylbenzidine was dissolved in 250 ml of dihexyl ether, and 100 mmol of hexane solution of butyllithium was slowly added dropwise to the solution. Then, after stirring at 110 ° C. for 2 hours, 19.3 g (50 mmol) of 4,4′-diiodobiphenyl and 0.48 g (25 mmol) of copper iodide were added and reacted at 200 ° C. for 24 hours.

  After cooling, the resulting reaction solution was filtered and extracted three times with boiling tetrahydrofuran. The filtrate and tetrahydrofuran solution were concentrated and purged with methanol solution to obtain the desired polymer. This operation was repeated three times.

Example 1
A thin film having a thickness of 50 nm was formed on a substrate of indium tin oxide-coated glass by a spin coating method using a dichloromethane solution of the polymer amino compound (1) as an organic hole injecting and transporting layer.

  Next, a thin film was formed as an organic light-emitting layer by vacuum evaporation of aluminum trisoxine to a thickness of 50 nm.

  Finally, a thin film was formed to a thickness of 200 nm by vacuum deposition of magnesium as a cathode. In this way, an organic electroluminescent element device was produced.

Examples 2-4
In Example 1, an organic electroluminescent device was produced in the same manner as in Example 1 except that the polymer amino compound (2), (3) and (4) were used instead of using the polymer amino compound (1). Was made.

Example 5
A thin film having a thickness of 70 nm was formed on a substrate of indium tin oxide-coated glass by a spin coating method using a dichloromethane solution of a polymer amino compound (7) as an organic hole injecting and transporting layer.

  Next, a thin film was formed as an organic light emitting layer by vapor deposition of aluminum trisoxine to a thickness of 100 nm.

  Further, a thin film was formed as an organic electron injecting and transporting layer by vapor deposition of the following oxadiazole compound (A) to a thickness of 50 nm.

最後に、陰極としてマグネシウムを蒸着により２００ｎｍの厚さになるように薄膜を形成した。 このようにして、有機電界発光素子を作製した。

Finally, a thin film having a thickness of 200 nm was formed by vapor deposition of magnesium as a cathode. In this way, an organic electroluminescent element was produced.

Examples 6-8
In Example 5, an organic electroluminescent device was produced in the same manner as in Example 5 except that instead of using the polymer amino compound (7), the polymer amino compound (8), (9), (10) was used. Was made.

Example 9
A thin film having a thickness of 50 nm was formed on a substrate of indium tin oxide-coated glass by a spin coating method using a dichloromethane solution of a polymer amino compound (11) as a light emitting layer.
Next, a thin film was formed as an organic electron injecting and transporting layer by vapor deposition of the oxadiazole compound (A) to a thickness of 20 nm.
Finally, a thin film having a thickness of 200 nm was formed as a cathode by vapor deposition of Mg and Ag with an atomic ratio of 10: 1. In this way, an organic electroluminescent element was produced.

Example 10
A thin film having a thickness of 20 nm was formed on a substrate of indium tin oxide-coated glass by a spin coating method using a dichloromethane solution of a polymer amino compound (13) as an organic hole injecting and transporting layer.
Further, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine is vacuum-deposited to obtain a 40 nm-thick hole transport layer. It was.
Next, a thin film was formed by vapor deposition of a tris (8-hydroxyquinoline) aluminum complex to a thickness of 50 nm.
Finally, a thin film having a thickness of 200 nm was formed as a cathode by vapor deposition of Mg and Ag with an atomic ratio of 10: 1. In this way, an organic electroluminescent element was produced.

Example 11
A polymer amino compound (14) was dissolved in dichloromethane on an indium tin oxide-coated glass substrate, and a hole injection layer having a thickness of 50 nm was obtained by spin coating.
Next, a light emitting layer was formed by vapor deposition of a tris (8-hydroxyquinoline) aluminum complex to a thickness of 20 nm.
Further, an electron injection layer of oxadiazole compound (A) having a film thickness of 20 nm was obtained by a vacuum deposition method.
Finally, a thin film having a thickness of 200 nm was formed as a cathode by vapor deposition of Mg and Ag with an atomic ratio of 10: 1. In this way, an organic electroluminescent element was produced.

Examples 12 to 13 and Reference Example 1
In Example 11, the organic electroluminescent device was exactly the same as Example 11 except that the polymer amino compound (18) was replaced with the polymer amino compound (18) instead of using the polymer amino compound (14). Was made.

Reference example 2
A polymeric amino compound (24) and tris (8-hydroxyquinoline) aluminum complex are dissolved in tetrahydrofuran at a ratio of 3: 2 on an indium tin oxide-coated glass substrate, and a light-emitting layer having a thickness of 100 nm is formed by spin coating. Obtained.
Next, a thin film was formed by vapor deposition of Mg and Ag with an atomic ratio of 10: 1 as a cathode to a thickness of 200 nm. In this way, an organic electroluminescent element was produced.

Examples 14-16
The organic electroluminescent device was exactly the same as Reference Example 2 except that instead of using the polymer amino compound (24) in Reference Example 2 , the polymer amino compound (29), (31), (36) was used instead. Was made.

Evaluation The electroluminescent elements obtained in Examples 1 to 16 and Reference Examples 1 and 2 were used, with the glass electrode serving as an anode, the voltage at which light emission started when a voltage was gradually applied, and the maximum light emission luminance and the time. The voltage of was measured. The results are summarized in Table 1.

As can be seen from Table 1, the organic electroluminescent device of this example started to emit light at a low potential and showed good emission luminance.
Further, the device obtained in Example 1 was allowed to continuously emit light at an initial voltage of 6 V under an inert atmosphere of nitrogen gas, and the half-life of the emission luminance (time until the luminance was reduced to half) was measured. there were.

  The organic electroluminescent element of this example had little decrease in output, and stable light emission with a long lifetime could be observed.

  According to the present invention, an electroluminescent element having high durability and low light emission starting voltage can be obtained by containing the polymer amino compound represented by the general formula (I) in the organic light emitting layer.

The schematic block diagram of the example of 1 structure of an electroluminescent element. The schematic block diagram of the example of 1 structure of an electroluminescent element. The schematic block diagram of the example of 1 structure of an electroluminescent element. The schematic block diagram of the example of 1 structure of an electroluminescent element.

Explanation of symbols

1: Anode 2: Hole injection transport layer 3: Organic light emitting layer 4: Cathode 5: Electron injection transport layer 6: Organic light emitting material 7: Charge transport material 8: Lead wire

Claims (1)

A material for an electroluminescent device comprising an amino compound having a repeating unit structure represented by the following general formula (I) (excluding a compound overlapping with the compound of the following general formula (II));

(In the formula, Ar ₁ and Ar ₃ each independently represent a phenylene group or a diphenylene group which may have a substituent; Ar ₂ and Ar ₄ each independently have a substituent. 1 represents an integer of 0 to 2, except when l and m are simultaneously 0; m represents an integer of 0 to 2; n represents a natural number of 5 to 1000 Represents);

(In formula (II): R is independently C _1-24 hydrocarbyl, hydrocarboxyl, hydrothiocarboxy, hydroarylcarboxy, or hydrothioarylcarboxy in each occurrence; Ar ₁ and Ar ₂ are each occurrence Independently a C _6-18 aryl moiety _optionally substituted with one or more C _1-24 hydrocarbyl, hydrocarboxyl, hydrothiocarboxy, hydroarylcarboxy, or hydrothioarylcarboxy; A is each occurrence Is independently hydrogen or halogen at each occurrence; x is independently a positive number between 0 and 1; n is an integer from 0 to 4; and m is from 5 to 1000 Is the number of).

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