JPH10102051A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject element containing a terylene derivative compound as an organic electric field-generating material, generating stable red light, high in reliability, and useful as an electroluminescence element. SOLUTION: This organic electroluminescent element has a structure in which an organic electroluminescent layer containing an organic electroluminescent material is nipped between an anode and a cathode. The organic electroluminescent material contains a terylene derivative compound, preferably a compound of the formula [R is H, an alkyl, an alkoxy, a halogen, (substituted) phenyl] (e.g. 2,5,10,13-tetra-tert-butylterylene). The objective element has preferably a structure produced by laminating an anode, an organic electroluminescent layer comprising a hole transport layer, an luminescent layer and an electron transport layer, and a cathode in this order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device containing an organic electroluminescent material which emits light by current injection as a component thereof, and more particularly, to an organic electroluminescent device characterized by a red-emitting organic electroluminescent material. Related to the element.

[0002]

2. Description of the Related Art Conventionally, a cathode ray tube has been most widely used as an image display for an information communication terminal device such as a computer and a television, which has features of high luminance and good color reproducibility, but is bulky. It is heavy and has large power consumption. Therefore, there is a great demand for a lightweight, thin, and highly efficient flat panel display. Currently, the most frequently used flat panel display is an active matrix drive type liquid crystal display.However, it has a narrow viewing angle, and when using a backlight because it is not self-luminous, the power consumption of this backlight is large. There is a problem that it does not have a sufficient response to a high-definition and high-speed video signal which is expected to be put to practical use, and there are problems such as uniformity and high cost in manufacturing a large screen display. There is a possibility of light emitting diodes as a candidate for a flat panel display instead of a liquid crystal display, but it is difficult to manufacture a light emitting diode matrix on a single substrate with a large area, and it has not become a low-cost display to replace a cathode ray tube .

Recently, an organic electroluminescent device has been attracting attention as a flat panel display having a possibility of solving these problems. This is advantageous in that self-luminous light has a high response speed and has no viewing angle dependence.

An organic electroluminescent device using an organic light emitting material is one in which an organic electroluminescent layer containing an organic electroluminescent material is sandwiched between a translucent anode and a metal cathode. CW
Tang and SAVanSlyke use a single-hetero-type organic electroluminescent layer that emits light when the holes and electrons injected from the anode and cathode into the organic electroluminescent layer recombine with a two-layer organic electroluminescent layer consisting of a hole transport layer and an electron transport layer. Phys. Lett., 51 (12), 913-915 (Sept. 198).
7)). In this device structure, either the hole transport layer or the electron transport layer also functions as the light emitting layer. Light emission occurs in a wavelength band corresponding to the energy gap between the ground state and the excited state of the light emitting material. The two-layer structure of the organic electroluminescent layer has greatly reduced the driving voltage and improved the luminous efficiency. Since then, research aimed at application to all solid-state flat panel displays has been made. Is underway. Various metal complexes such as a zinc complex and an aluminum complex have been proposed as light emitting materials for obtaining high luminous efficiency.

[0005] As for the element structure, C. Adachi, S. To
kito, T.Tsutsui, a hole transport layer by S.Saito, example of a double heterostructure consisting of three layers of the light emitting layer and the electron transport layer Jpn. J. Appl. Phys. 27 -2, L269-L271 (1988) Was reported to. Further, a light emitting material is included in the electron transport layer,
CWTang, SAVanSlyke, and CHChen have proposed a two-layer structure consisting of an electron transport layer also serving as a light emitting layer and a hole transport layer.
l. Phys. 65 -9, 3610-3616 (1989). From these reports, the possibility of high-brightness light emission at a low voltage has been verified, and research and development of organic electroluminescent devices have been very actively performed in recent years.

However, there are still some problems to be solved for practical use of the organic EL device. One of them is the development of an excellent red light emitting material for realizing a multi-color or full-color flat panel display. The red light-emitting materials that have been reported so far include red fluorescent organic dyes and europium metal complexes.

Of these, fluorescent organic dyes include:
CWTang, SAVanSlyke, and CHChen reported in the aforementioned 1989 report that 4-dicyanomethylene-2-methyl-6- (pd
iaminostyryl) -4H-pyran is used in the electron transport layer. J.Kido, M.Miura, K, Nagai are Scienc
e 267, containing at 1332-1334 (1995) published a report, as a red light-emitting material constituting the organic electroluminescent element of white light emission, also the electron transport layer in _{Nile Red (C 20 H 18 N} 2 O 2) Not used. Also Perile
An example in which a ne (C ₂₀ H ₁₂ ) thin film is used for red light emission of an organic electroluminescent device having a double hetero structure is described in C. Adachi, S. Tokito,
... T.Tsutsui, by S.Saito, Jpn J. Appl Phys 27 -
2, L269-L271 (1988). Furthermore, there is a report that this perylene derivative was used as a red light emitting material. For example, M.Hiramoto, T.Imahigashi, M.Yokoyama are N, N'-d
imethyl-3,4,9,10-perylenedicarboimide thin film is sandwiched between Au electrodes (Appl. Phys. Lett., 64-
2, 187-188 (1993)). In addition, T.Katsume, M.Hiramo
To, M. Yokoyama reported that N, N'-bis (2,5-di-tert-butylphen
yl) -3,4,9,10-perylenedicarboimide thin film sandwiched between a hole injection layer and an electron transport layer (Appl. Phys.
Let., 64 -19, 2546-2548 ( 1993)).

With respect to europium complexes, for example, Kid
o, K. Nagai, Y. Okamoto, T. Skotheim are Chemistry Lett
ers, 1267-1270 (1991), tris (theonyltrifluor
oacetonato) Eu (III) complex with poly (methylphenylsilan
e) It was reported that red light emission was obtained by being included in e). Also, J.Kido, H.Hayase, K.Hongawa, K, Nagai, K.
Okuyama is, Appl. Phys.Lett., 65 -17 , 2124-2126 (199
In 4), tris (1,3-diphenyl-1,3-propanedino)-(1,
10-phenanthroline) Eu (III) complex with 2- (4-biphenyl) -5-
We report an example in which phenyl 1,3,4-oxasol was used. N.Takada, T.Tsutsui, S.Saito are Jpn.
In J. Appl. Phys. 33 , Part 2, 6B, L863-L866 (1994), tris (theonyltrifluoroacetonato)-(4,7-dipheny
We report an example of a micro-optical resonator using an (1,1,10-phenanthroline) Eu (III) complex thin film as a light-emitting layer of an organic electroluminescent device having a double heterostructure. Furthermore, T.Sato, M.Fujit
a, T. Fujii, Y. Hamada, Jpn. J. Appl. Phys. 34 , P
art 1, 4A, 1883-1887 (1994), tris (theonylt
rifluoroacetonato)-(1,10-phenanthroline) Eu (III)
Red light emission is obtained by including the complex in the electron transport layer.

[0009]

However, none of these red light-emitting materials has reached a satisfactory level in terms of color purity, luminance and stability. The present invention has been made in view of such technical background, and has as its object to provide an organic electroluminescent material capable of emitting stable red light and a highly reliable organic electroluminescent device using the same.

[0010]

SUMMARY OF THE INVENTION The present invention proposes to achieve the above object. That is, the organic electroluminescent device of the present invention is an organic electroluminescent device having a structure in which an organic electroluminescent layer containing an organic electroluminescent material is sandwiched between an anode and a cathode, wherein the organic electroluminescent material is a terylene derivative compound It is characterized by including. As such terylene derivative compounds, the following general formula (1)
Are exemplified.

[0011]

Embedded image (Wherein, R represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a phenyl group and a substituted phenyl group,
They may be the same or different. )

As a layer structure of the organic electroluminescent device of the present invention, an organic electroluminescent layer in which a hole transport layer, a light emitting layer and an electron transport layer are stacked in this order on an anode, and a cathode are sequentially stacked in this order. One having the structure described above is exemplified.
When the hole transport layer or the electron transport layer also functions as the light emitting layer, it is not necessary to provide the light emitting layer independently. With such a layer structure, it is possible to manufacture a stable red-emitting electroluminescent element.

The terrylene derivative compound used as the red light-emitting material of the organic electroluminescent device of the present invention is a compound that is stable at high temperatures and is sublimable, so that a film can be easily formed by means such as vacuum evaporation. It is.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the organic electroluminescent device of the present invention will be described in more detail with reference to the drawings, but the present invention is not limited to these embodiments. First, a device configuration in which the organic electroluminescent device of the present invention is applied to an EL device will be described with reference to schematic cross-sectional views shown in FIGS. Among these, FIG. 1A shows the element configuration of an organic electroluminescent element having a double hetero structure, and FIG. 1B shows the element configuration of an organic electroluminescent element having a single hetero structure.

In each of the element structures, reference numeral 1 denotes a substrate made of a transparent material such as glass or plastics or other suitable material. When the organic electroluminescent device is used in combination with another display device or a driving circuit, the substrate 1
Can be shared. Reference numeral 2 denotes an anode, ITO
(Indium Tin Oxide) or a transparent conductive material such as SnO ₂ . Reference numeral 3 denotes a hole transporting layer, which is not particularly limited as a hole transporting material. For example, any of known substances such as aromatic amines and pyrazoline can be used. A thin film made of an organic substance or an organometallic compound may be inserted between the anode 2 and the hole transport layer 3 in order to improve hole injection efficiency. The hole transporting layer 3 may be a single layer, or may have a laminated structure to improve hole transporting ability. When a terylene derivative compound is used for the hole transport layer 3, the terylene derivative compound may be used alone or in combination with another hole transport material. When the hole transport layer 3 has a laminated structure, at least one of the layers only needs to contain a terylene derivative compound.

Reference numeral 4 denotes a light emitting layer. In the case of the single hetero structure shown in FIG. 1B, either the hole transport layer 3 or the electron transport layer 5 also serves as the light emitting layer 4, and the light emitting layer 4 is present as shown in FIG. This is only the case of a single heterostructure. The terrylene derivative compound is
It may be used alone in the light emitting layer 4 or may be used as a mixture with an electron transporting material. The light-emitting layer 4 has a laminated structure of a single layer, a thin film of an electron transport material and a thin film of a mixture of a light-emitting material and an electron transport material, or a laminate of a thin film of an electron transport material and a thin film of a light-emitting material. It may be a structure.

Reference numeral 5 denotes an electron transport layer, which may be a metal complex of aluminum or zinc, an aromatic hydrocarbon compound, an oxadiazole compound, or the like. The terrylene derivative compound may be used as a mixture with these electron transporting materials, or may be used alone as the electron transporting material.

The above-described hole transport layer 3, light-emitting layer 4, and electron transport layer 5 are main structures constituting an organic electroluminescent layer, and a terylene derivative compound can be used for any of them. Further, in addition to the hole transport layer 3, the light emitting layer 4, and the electron transport layer 5, a thin film for controlling the transport of holes or electrons may be included in the layer structure of the organic electroluminescent layer in order to improve luminous efficiency. It is possible. Further, in order to improve the light emitting performance, any one or more of the hole transport layer 3, the light emitting layer 4, and the electron transport layer 5 may contain a fluorescent material.

Reference numeral 6 denotes a cathode. As an electrode material, for example, an active metal having a low work function such as Li, Mg or Ca;
An alloy with Ag, Al, In or the like or a laminated structure can be adopted. In the case of a transmissive organic electroluminescent element, by adjusting the thickness of the cathode 6, a light transmittance suitable for the intended use can be obtained. Further, in order to supplement the conductivity of the cathode 6, a transparent conductive film such as ITO or SnO ₂ may be further laminated and used. Reference numeral 5 denotes a protective layer for protecting or sealing the organic electroluminescent element, and is not limited to an organic material such as plastics or an inorganic material such as SiO _{2 as} long as it is a material satisfying airtightness such as water vapor or oxygen. Can also be adopted.

In the EL device shown in FIG.
By applying a DC voltage between the anode 2 and the cathode 6,
The holes injected from the anode 2 pass through the hole transport layer 3,
In addition, electrons injected from the cathode 6 pass through the electron transport layer 5,
Each reaches the light emitting layer 4. As a result, recombination of electrons / holes occurs in the light emitting layer 4, from which light emission of a predetermined wavelength is generated. In the case of the layer configuration in which the light emitting layer is omitted as shown in FIG. 1B, light of a predetermined wavelength is generated from the interface between the hole transport layer 3 and the electron transport layer 5. These light emissions are observed from the substrate 1 side. When the cathode 6 and the protective layer 7 are translucent, they are also observed from the protective layer 7 side.

A specific example in which the light emitting device of the present invention is applied to an actual organic EL device is shown in a schematic perspective view of FIG. E in FIG.
The L element is obtained by disposing a laminate including the hole transport layer 3 and at least one of the light emitting layer 4 and the electron transport layer 5 between the anode 2 and the cathode 6. The anode 2 and the cathode 6 are both patterned in a stripe shape and are orthogonal to each other in a matrix. The control circuits 8 and 9 having a built-in shift register apply a signal voltage in chronological order, and emit light at the intersection. It was done. The EL element having such a configuration can be used not only as a display for characters and symbols, but also as an image reproducing device.
By arranging the stripe pattern of the anode 2 and the cathode 6 for each color of red (R), green (G), and blue (B), it is possible to configure a multi-color or full-color all solid-state flat panel display. .

EXAMPLES Synthesis of Terylene Derivative Compound The terylene derivative compound used in the present invention is, for example, Karl
-Heinz Koch and KlausMuellen in Chem. Ber., 124 , 2091
2100 (1991). The general route of this synthesis method is as shown in the following formula (2), starting from a 2,7-substituted naphthalene corresponding to a substituent of the final product as a raw material, and brominating this raw material to form 1-bromo After conversion into a -3,6-substituted product, bromine is converted into boric acid, coupled with a 1,4-dibromo-substituted naphthalene, and then anion cyclized to obtain a final product.

[0023]

Embedded image

Synthesis of 2,5,10,13-tetra-tert-butylterrylene Next, as a specific example, 2,5,10,13-tetra-tert-butylterryl
The details of the method for synthesizing ene are shown below. Other terylene derivative compounds can be obtained according to this method. Starting material
2,7-di-tert-butylnaphthalene was obtained by the method described below. That is, 200 g of naphthalene and tert-bu
To 480 g of the mixture of tylchloride was added 300 mg of aluminum chloride. After a vigorous reaction with evolution of hydrogen chloride gas, the reaction mixture solidified after about 30 minutes. To complete the reaction, the solidified reaction mixture was heated on a water bath for another 3 hours, allowed to cool, and then left at room temperature for 8 hours. The solid reaction mixture is dissolved in 3.3 l of boiling ethanol, 210 g of thiourea are added,
After cooling, the filtrate was collected by filtration. Then another 80g
The boiling ethanol treatment with thiourea, cooling and filtration were repeated. After evaporating off the solvent, the residue
The mixture was ground with 1 l of distilled water and extracted three times with chloroform. The organic layer was dried over magnesium sulfate, filtered, and the solvent was evaporated. 125 g of 2,7-di-
tert-butylnaphthalene was obtained. The yield was 34% based on naphthalene.

Next, 1-bromo-3,6-di-tert-butylnaphthale
Bromination was performed to obtain ne. 33g of 2,7-di-
Tert-butylnaphthalene was dissolved in 400 g of carbon tetrachloride, and 300 mg of iron powder was added as a catalyst. 22.4m
g of bromine in 100 ml of carbon tetrachloride,
The mixture was added at room temperature over a period of 1 hour using a dropping funnel, and the mixture was stirred and reacted for 8 hours. Reactions were performed in the dark. 0.5
300 ml of M sodium hydroxide solution were added and the mixture was
Stir for hours to hydrate. Next, the organic layer was separated, dried over magnesium sulfate, and filtered. After evaporating the solvent,
The residue was recrystallized from methanol to give 27 g of the desired product 1-br
omo-3,6-di-tert-butylnaphthalene was obtained. The yield is 80
%Met.

Boron oxidation of 1-bromo-3,6-di-tert-butylnaphthalene was performed as follows. 1-bromo-3,6-di-ter
25 g of t-butylnaphthalene was dissolved in dry diethyl ether and cooled to -78 ° C under nitrogen. 38 ml of a 2.5 M solution of butyllithium in hexane was injected through a syringe, the mixture was stirred for 1 hour, and then the cooling bath was removed. A separate reaction vessel was charged with 250 ml of a 2.8-fold molar amount of triisopropoxyborane in dry diethyl ether based on aryl bromide and cooled to -78 ° C under nitrogen. . With vigorous stirring, the previously prepared organolithium compound was slowly added over 1 hour using a metal mantle tube. After complete addition, the mixture was stirred at low temperature for 1 hour and further at room temperature for 8 hours. The mixture is then
The mixture was hydrated with 300 ml of an aqueous M hydrochloric acid solution for 30 minutes. The layers were separated, the organic layer was dried over magnesium sulfate, and the solvent was evaporated. The residue was dissolved in 100 ml of low boiling petroleum ether, 10 ml of distilled water was added and the mixture was stirred at room temperature. After about 12 hours, the product precipitated as colorless crystals. The product was filtered by suction, washed with a small amount of petroleum ether, and dried in a vacuum desiccator at 60 ° C. and 20 Torr. The obtained 3,6-di-tert-butyl-1- (dihydrixyboryl) na
The amount of phthalene was 15 g, and the yield was 67%. The melting point was 270 ° C., which was in agreement with the literature value.

3,6-di-tert-butyl-1- (dihydroxyboryl) na
The coupling reaction between phthalene and 1,4-dibromonaphthalene was performed using a palladium catalyst. The reaction was performed in a dark place under a nitrogen atmosphere. 3,6-di-tert-butyl-1- (dih
1.37 g of ydrixyboryl) naphthalene and 340 mg of tetrakis (triphenylphosphine) palladium (0) were suspended in 20 ml of toluene, and then 10 ml of a 2M aqueous potassium carbonate solution was added. The mixture was refluxed for 3 days with vigorous stirring. After cooling, the layers were separated, and the aqueous layer was repeatedly extracted with a small amount of chloroform. The organic layer was dried using magnesium sulfate, and precipitated by adding ethanol.
3,3 '', 6,6 ''-tetra-tert-butyl-1,1 ': 4,1''-ternaphtha
got lene. The reaction yield was 78%. The purity of the target substance was confirmed to be a single substance by thin-layer chromatography using petroleum ether as a developing solution. This target material emitted strong blue fluorescence upon irradiation with ultraviolet light in the solution. The melting point was 275 ° C., which was in agreement with the literature value.

3,3 '', 6,6 ''-tetra-tert-butyl-1,1 ': 4,
The cyclization of 1 ''-ternaphthalene was carried out in pure argon gas without humidity. 3,3 '', 6,6 ''-tetra-tert
-butyl-1,1 ': 4,1''-ternaphthalene 2.3g 150
Dissolved in 1 ml of dry 1,2-dimethoxyethane. Schlen
The use of a k-type reaction flask enables a reaction in a dry argon stream. 1.8 g of a piece obtained by cutting metal potassium from which surface oxidation was removed into small pieces was added. The solution is cycled through a freeze / thaw cycle in a vacuum, 10 ^-3 T
Degassed at orr. Thereafter, the flask was sealed and the reaction was performed in a vacuum. The mixture was kept stirring at room temperature for 7 days. The progress of the reduction can be seen by the color of the mixture. In the first stage of the reaction, a green color appears after a few hours, indicating the formation of radical monoanions. The next change to red indicates the formation of a dianion. At the end of the reaction, the reaction mixture turns blue-violet or blue due to the formation of the perylene dianion. The remaining metallic potassium was removed in argon, and 2.5 g of cadmium chloride just sublimated was added.
The mixture was stirred for one day. After filtering this mixture, the solid was washed with chloroform. 2,3 ', 5,6'-tetra-tert-butyl-9 along with the final product terylene derivative compound
-(1'-naphtyl) perylene was obtained. After concentrating the collected organic solution, the residue was subjected to chromatography using aluminum oxide as a carrier using petroleum ether as a developing solution to obtain the 2,3 ′, 5,6′-tetra-tert-butyl-9- ( 1'-nap
(htyl) perylene was separated to obtain 910 mg. The yield was 40%. Chloroform was gradually added to the developing solution to obtain a mixture of petroleum ether / chloroform (5: 1), thereby obtaining 550 mg of a terylene derivative compound as a final product. This product showed a very strong red fluorescence in solution.

2,3 ', 5,6-tetra-tert-butyl- (1'-naphtyl)
perylene 600mg, anhydrous aluminum chloride 600m
g and 600 mg of anhydrous copper chloride were stirred in 70 ml of carbon disulfide in a nitrogen stream at room temperature for 8 hours. At the end of the reaction, a dark green-black precipitate had formed. After decanting the solvent, the solid was hydrated using ice and a dilute aqueous ammonia solution. The suspension was repeatedly extracted with a small amount of chloroform (30 ml) until no red color due to the final target was observed in the organic layer. After drying over magnesium sulfate and filtering the organic layer, the solvent was evaporated. 20m of residue
Dissolved in 1 l of chloroform and added 5 g of aluminum oxide. The solvent was evaporated and the product was loaded on aluminum oxide. Thereafter, the product was purified by aluminum oxide column chromatography. By using cyclohexane for the developing solution, only the reaction by-product was developed. The target terylene derivative compound was recovered by refluxing the column packing material dried under nitrogen with chloroform. After evaporation of the solvent, the residue was recrystallized from ethanol,
200 mg of the desired compound (reaction yield 34%) was obtained. The melting point was 370 ° C., which was in agreement with the literature value. Target compound 2,5,
10,13-tetra-tert-butylterrylene was further purified by repeated vacuum sublimation.

Example 1 This example is an example in which a terylene derivative compound was applied to a hole transport layer to produce an organic electroluminescent device. In a vacuum evaporation apparatus, a glass substrate having an anode made of ITO formed on one surface was set at a position 25 cm above the evaporation source. As a deposition mask, a plurality of 2.0 mm ×
A metal mask having an opening of 2.0 mm is arranged in close proximity to the substrate, and under a vacuum of 10 ⁻⁴ Pa or less by a resistance heating method, for example, N, N′-diphenyl-N, N'-bis (3
-mrthlphenyl) 1,1'-biphenyl-4,4'-diamine (TP
D) and 2,5,10,13-tetra-tert synthesized earlier
-butylterrylene was evaporated from separate evaporation boats to form a hole transport layer comprising a mixed film of two types of hole transport materials on the anode. The deposition rate was individually controlled by a film thickness monitor using two quartz oscillators, and the ratio of the terylene derivative compound in the hole transport layer was controlled. The deposition rate of the entire hole transport layer is 0.2 to 0.4 nm / s
ec, and the film thickness was 50 nm.

[0031]

Embedded image

Next, in order to enhance the luminous efficiency in the hole transport layer, 2,9-dimethyl-4,7-dipheny
l-1,10-phenanthroline was deposited to a thickness of 15 nm.
Subsequently, for example, tris- (8-hydroxyquinoline) aluminum (hereinafter abbreviated as Alq) represented by the following formula (4) was deposited to a thickness of 50 nm as an electron transporting layer. The deposition rate of each of these layers was controlled between 0.2 and 0.4 nm / sec by monitoring the film thickness using a quartz oscillator.

[0033]

Embedded image

Aluminum is used as the cathode material,
This was also formed to a thickness of 200 nm by vapor deposition.
A basic form of an organic electroluminescent device was produced by the method described above.

Evaluation of Light Emitting Characteristics The organic electroluminescent device of Example 1 manufactured as described above was evaluated for light emitting characteristics by applying a voltage under a nitrogen atmosphere. The emitted light was red, and as a result of spectral measurement, a spectrum having an emission maximum at 580 nm shown in FIG. 3 was obtained, and it was confirmed that the emitted light was due to the terrylene derivative compound. For the spectroscopic measurement, a spectroscope using a photodiode array made by Otsuka Electronics as a detector was used. When the applied voltage was gradually increased and the luminance was measured with a luminance meter, the applied voltage 1
A luminance of 1000 cd / m ² was obtained at 5 V. This emission was stable, and the luminance did not significantly decrease during the observation time.

Example 2 In this example, an organic electroluminescent device was produced by incorporating the terylene derivative compound of the present invention into an electron transport layer. In a vacuum evaporation apparatus, a glass substrate having an anode made of ITO formed on one surface was set at a position 25 cm above the evaporation source. As a vapor deposition mask, a plurality of metal masks each having a unit opening of 2.0 mm × 2.0 mm are arranged close to the substrate, and 10 ^-4 P is applied by a resistance heating method.
Under a vacuum below a, as an example, the lower TPD was evaporated from an evaporation boat to form a hole transport layer on the anode. The deposition rate is 0.2 to 0.2
Control was performed during 0.4 nm / sec, and the film thickness was set to 50 nm.

Next, Alq was used as an electron transport material, and 2,5,10,13-tetra-tert-butyl previously synthesized with Alq.
Terrylene was evaporated from separate evaporation boats to form an electron transport layer. The deposition rate was individually controlled by a film thickness monitor using two quartz oscillators, and the ratio of the terylene derivative compound in the electron transport layer was controlled. The deposition rate of the entire electron transport layer was controlled between 0.2 and 0.4 nm / sec, and the film thickness was 50 nm. Aluminum was used as the cathode material, and was also formed to a thickness of 200 nm by vapor deposition to produce a basic form of the organic electroluminescent device according to Example 2.

Evaluation of Light Emitting Characteristics The organic electroluminescent device of Example 2 thus manufactured was evaluated for light emitting characteristics by applying a voltage in a nitrogen atmosphere. The luminescent color was red, and as a result of spectral measurement, a spectrum having a luminescent maximum near 580 nm shown in FIG. 3 was obtained, and it was confirmed that the luminescence was due to the terrylene derivative compound. The red light emission intensity depends on the concentration of the terylene derivative compound in the electron transport layer, and the concentration of the terylene derivative compound with respect to Alq is in the range of 0.1 to 2.0 mol%, preferably 0.2 to 1.0 mol%. Sometimes it was the largest. When the applied voltage was gradually increased and the luminance was measured by a luminance meter, a luminance of 800 cd / m ² was obtained at an applied voltage of 12 V. This emission was stable, and the luminance did not significantly decrease during the observation time.

Example 3 In this example, an organic electroluminescent device was produced using the terylene derivative compound of the present invention as the electron transport layer material itself. In a vacuum deposition apparatus, a glass substrate having an anode made of ITO formed on one surface is placed above the deposition source by two times.
It was set at a position of 5 cm. As a deposition mask,
A plurality of metal masks each having a unit opening of 2.0 mm × 2.0 mm are arranged close to the substrate, and TPD is evaporated from an evaporation boat as an example under a vacuum of 10 ⁻⁴ Pa or less by a resistance heating method. Thus, a hole transport layer was formed on the anode. The deposition rate is controlled between 0.2 and 0.4 nm / sec by a film thickness monitor using a quartz oscillator.
nm.

Next, it was previously synthesized as an electron transporting material.
An electron transport layer and a light emitting layer were formed by vapor deposition using 2,5,10,13-tetra-tert-butylterrylene. The deposition rate is controlled by a film thickness monitor using a quartz oscillator, and is set to 0.2 to 0.
Control was performed within 4 nm / sec, and the film thickness was set to 20 nm.
Aluminum was used as a cathode material, which was also formed to a thickness of 200 nm by vapor deposition to produce a basic form of the organic electroluminescent device according to Example 3.

Evaluation of Light Emitting Characteristics Light emitting characteristics were evaluated by applying a voltage to the organic electroluminescent device of Example 3 thus manufactured in a nitrogen atmosphere. The luminescent color was red, and as a result of spectral measurement, a spectrum having a luminescent maximum near 580 nm shown in FIG. 3 was obtained, and it was confirmed that the luminescence was due to the terrylene derivative compound. When the applied voltage was gradually increased and the luminance was measured using a luminance meter, a luminance of 420 cd / m ² was obtained at an applied voltage of 20 V. In this embodiment, the reason why the luminance is small at a high applied voltage regardless of the thickness of the electron transport layer is smaller than that of the previous embodiment 2 is considered that the electron transport performance of the terylene derivative compound itself is smaller than Alq. This emission was stable, and the luminance did not significantly decrease during the observation time.

Example 4 In this example, an organic electroluminescent device was produced by incorporating the terrylene derivative compound of the present invention in the electron transport layer according to Example 2 and further combining it with an auxiliary layer consisting of only Alq. is there. In a vacuum evaporation apparatus, a glass substrate having an anode made of ITO formed on one surface was placed 25 cm above the evaporation source.
Setting. As a vapor deposition mask, a plurality of metal masks each having a unit opening of 2.0 mm × 2.0 mm are arranged close to the substrate, and 10 ^{-4 is applied} by resistance heating.
As an example, the lower TPD was evaporated from an evaporation boat under a vacuum of Pa or less to form a hole transport layer on the anode. The deposition rate is 0.2 to 0.2
Control was performed during 0.4 nm / sec, and the film thickness was set to 50 nm.

Next, Alq was used as an electron transporting material, and 2,5,10,13-tetra-tert-butyl previously synthesized with Alq.
Terrylene was evaporated from separate evaporation boats to form an electron transport layer. The deposition rate was individually controlled by a film thickness monitor using two quartz oscillators, and the ratio of the terylene derivative compound in the electron transport layer was controlled. First, after a layer of only Alq was formed to a thickness of 10 nm, Alq and the terylene derivative compound of the present invention were co-evaporated. The thickness of the co-deposited layer is 5-4
0 nm, preferably 10 to 30 nm. The deposition rate of each layer was controlled between 0.2 and 0.4 nm / sec.

Further, in the present embodiment, an auxiliary layer of Alq alone was formed on the electron transport layer. The deposition rate is the same as the deposition rate of the electron transport layer, 0.2 to 0.4 nm / sec.
Controlled during c. The total thickness of the auxiliary layer and the electron transport layer was set to 50 nm. Aluminum was adopted as the cathode material, and this was also 200 nm by evaporation.
To produce a basic form of the organic electroluminescent device according to Example 4.

Evaluation of Light Emitting Characteristics The organic electroluminescent device of Example 4 manufactured as described above was evaluated for light emitting characteristics by applying a voltage in a nitrogen atmosphere. The luminescent color was red, and as a result of spectral measurement, a spectrum having a luminescent maximum near 580 nm shown in FIG. 3 was obtained, and it was confirmed that the luminescence was due to the terrylene derivative compound. The emission intensity of red light depends on the concentration of the terylene derivative compound in the electron transport layer, and the concentration of the terylene derivative compound with respect to Alq is 0.1 to 2.0 mol%, preferably the same as in the organic electroluminescent device of Example 2. 0.2-1.0m
The maximum value was obtained in the range of ol%. Gradually increase the applied voltage,
When the luminance was measured using a luminance meter, a luminance of 1000 cd / m ² was obtained at an applied voltage of 12 V. The reason why the luminance was improved compared to Example 2 is considered that the optimum recombination region of holes and electrons was within the range of this example, and energy transfer from Alq in the excited state to the terylene derivative compound was efficiently achieved. Can be This emission was stable, and the luminance did not significantly decrease during the observation time.

Example 5 This example is an example in which an organic electroluminescent device was manufactured by using the terylene derivative compound of the present invention for the light emitting layer. In a vacuum evaporation apparatus, a glass substrate having an anode made of ITO formed on one surface was set at a position 25 cm above the evaporation source. As a deposition mask, a plurality of 2.0 mm ×
A metal mask having a unit opening of 2.0 mm is arranged close to the substrate, and TPD is evaporated from an evaporation boat as an example under a vacuum of 10 ⁻⁴ Pa or less by a resistance heating method.
A hole transport layer was formed on the anode. The deposition rate is 0.2 to 0.4 nm / sec by monitoring the film thickness using a quartz oscillator.
Control was performed during c, and the film thickness was set to 50 nm.

On this hole transport layer, the previously synthesized 2,5,
A light emitting layer composed of 10,13-tetra-tert-butylterrylene was formed by vapor deposition. The deposition rate was controlled by a film thickness monitor using a quartz oscillator, and was controlled between 0.2 and 0.4 nm / sec, and the film thickness was 10 nm.

Next, 50 nm of Alq was used as an electron transport layer.
m was formed by vapor deposition. The deposition rate is controlled by a film thickness monitor using a quartz oscillator, and is 0.2 to 0.4 nm.
/ Sec. Aluminum was used as a cathode material, which was also formed to a thickness of 200 nm by vapor deposition, to produce a basic form of the organic electroluminescent device according to Example 5.

Evaluation of Light Emitting Characteristics The organic electroluminescent device of Example 5 manufactured as described above was evaluated for light emitting characteristics by applying a voltage in a nitrogen atmosphere. The luminescent color was red, and as a result of spectral measurement, a spectrum having a luminescent maximum near 580 nm shown in FIG. 3 was obtained, and it was confirmed that the luminescence was due to the terrylene derivative compound. When the applied voltage was gradually increased and the luminance was measured by a luminance meter, a luminance of 800 cd / m ² was obtained at an applied voltage of 12 V. The luminescence was stable and the brightness did not significantly decrease during the observation time.

As described above, the organic electroluminescent device of the present invention
The present invention is not limited to the embodiments described in more detail with reference to various examples. For example, 2,5,1 listed in Examples as terylene derivative compounds
In addition to 0,13-tetra-tert-butylterrylene, the compounds having various substituents described above may be employed. Further, other red light emitting materials may be used in combination with the terylene derivative compound. In addition, as for the layer structure and the electrode structure of the organic electroluminescent layer, any conventionally known structures can be adopted.

[0051]

As is apparent from the above description, according to the present invention, it is possible to provide a stable organic electroluminescent device emitting red light.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an element configuration in which an organic electroluminescent element is applied to an EL element.

FIG. 2 is a schematic perspective view showing a device configuration in which an organic electroluminescent device is applied to an actual EL device.

FIG. 3 is an emission spectrum of the organic electroluminescent device of Example 1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... anode, 3 ... hole transport layer, 4 ... light emitting layer,
5: electron transport layer, 6: cathode, 7: protective layer, 8, 9: control circuit

Claims (5)

[Claims] 1. An organic electroluminescent device having a structure in which an organic electroluminescent layer containing an organic electroluminescent material is sandwiched between an anode and a cathode, wherein the organic electroluminescent material contains a terrylene derivative compound. Organic electroluminescent device. 2. The organic electroluminescent device according to claim 1, wherein the terylene derivative compound is represented by the following general formula (1). Embedded image (Wherein, R represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a phenyl group and a substituted phenyl group,
They may be the same or different. ) 3. An organic electroluminescent layer in which a hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order on an anode, and a cathode, in which the organic electroluminescent layer is sequentially laminated in this order. The organic electroluminescent device according to claim 1. 4. An organic electroluminescent layer in which a hole transport layer and an electron transport layer are laminated in this order on an anode, and a cathode has a structure in which they are laminated in this order. The organic electroluminescent device according to claim 1. 5. The optical device according to claim 1, wherein the organic electroluminescent device is an electroluminescent device.