JP2006191138A - White light emitting illumination device and white light emitting organic el element by single compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white light emitting illumination device and a white light emitting organic EL element utilizing at least one type of single white light emitting compounds as light emitting materials, capable of emitting white light with high brightness, and capable of prolonging a light emission lifetime. <P>SOLUTION: This light-emitting device comprises a light-emitting layer containing light-emitting materials on a substrate having electrodes formed thereon. The white light emitting compounds which are novel materials having specific kinaklydon skeletons and carbazole skeletons are adopted as the light-emitting materials. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a white light-emitting lighting device and a white light-emitting organic EL element using a single compound, and more specifically, emits white light with high luminance when at least one kind of a novel single white light-emitting compound is used as a light-emitting material. The present invention relates to a white light-emitting illumination device and a white light-emitting organic EL element that can be used and have a long light emission lifetime.

  Conventional lighting devices and organic EL elements aiming at white light emission include, for example, a red light emitting compound that emits red (R), a green light emitting compound that emits green (G), and blue (B) between a pair of electrodes. It has a light emitting layer formed by interposing a blue light emitting compound that emits light. The luminescent color of the three kinds of luminescent compounds was mixed to achieve white light emission.

  However, it has been difficult to adjust the balance of the colors emitted from each of the three light emitting compounds. In addition, since the compound that emits red light is likely to deteriorate, even if it is a white light emitting illumination device or an organic EL element capable of white light emission by adjusting the balance of the three colors at the beginning of manufacture, the compound that emits red light with the passage of time. By deteriorating, there is a problem that it becomes colored light emission or illumination light and the luminance is low. On the other hand, few compounds are known that emit white light with a single compound. Further, the conventional light emitting compound has a problem that the light emission lifetime is short.

  An object of the present invention is to use a white light emitting illumination device and a white light emitting device using a single compound, which uses a white light emitting compound which is a single compound capable of emitting white light, has a long light emission lifetime and can emit white light over a long period of time. The object is to provide a light-emitting organic EL device. Another object of the present invention is to provide a planar white light-emitting illumination device and a white tube that uses a white light-emitting compound that is a single compound capable of emitting white light and has a long light emission lifetime and capable of white light emission over a long period of time. The object is to provide a light emitting illumination device.

  As a result of diligent research to solve this problem, in the past, R, G, and B primary color dyes and a plurality of dyes were allowed to emit light and mixed to achieve white light emission, but white light emission was possible. The present inventors have found a novel single fluorescent new compound, and found that this single fluorescent new compound has a long emission lifetime and emits light with a large luminance, and reached the present invention.

Means for solving the problems are as follows:
A white light emitting illumination device comprising a light emitting layer containing a light emitting material on a substrate on which an electrode is formed, wherein the light emitting material is a white light emitting compound represented by the formula (1). It is a white light emitting illumination device using a compound.

R ¹ represents a hydrogen atom, an alkyl group, an aryl group or an arylalkyl group. R ² represents a hydrogen atom, an alkyl group, an aryl group or an arylalkyl group.

In a preferred embodiment of the white light emitting lighting device with a single compound of the present invention,
The white light emitting illumination device using the single compound is a single-layer organic EL element having the substrate and a light emitting layer containing the white light emitting compound represented by the formula (1) provided on the substrate. is there.

In a preferred embodiment of the white light emitting lighting device of the present invention,
The white light emitting illumination device includes a hole transport layer, a light emitting layer containing a white light emitting compound represented by the formula (1), and an electron transport layer provided on the substrate, laminated on the transparent substrate. A multilayer organic EL element
The light emitting layer is a layer formed by dispersing the white light emitting compound in a polymer,
The light emitting layer is a layer formed by depositing the white light emitting compound on the substrate,
The white light emitting illumination device is a planar light emitting illumination device or a tubular light emitting illumination device.

Other means for solving the above problems are as follows:
A white light-emitting organic EL device comprising a light-emitting layer containing a light-emitting material on a substrate on which an electrode is formed, wherein the light-emitting material is a white light-emitting compound represented by the formula (1). This is a white light-emitting organic EL device using one compound.

According to the present invention, white light emission using a single white light-emitting compound that has a visible light-emitting region of 400 to 700 nm, has a luminance of 2,000 Cd / m ² or more, and is capable of emitting white light even though it is a single substance. An illuminating device can be provided, and the white light emitting illuminating device can be used as a display, an illuminating device, or the like, so that it emits white light and can be illuminated. It can also be used sufficiently for night advertising devices, road sign devices, and the like.

  A white light emitting lighting device (hereinafter, simply referred to as a white light emitting lighting device) using a single compound according to the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a cross-sectional structure of a white light-emitting illumination device that is also a single-layer organic EL element. As shown in FIG. 1, the white light emitting illumination device A is formed by laminating a light emitting layer 3 containing a light emitting material and an electrode layer 4 in this order on a substrate 1 on which a transparent electrode 2 is formed. The white light-emitting illuminating device A is a planar light-emitting illuminating device as long as the substrate spreads in a planar shape and has a planar shape as a whole, and the substrate 1 in FIG. If it has the form which became tubular as, it will become a tubular light-emitting illuminating device similar to a fluorescent lamp. In addition, this tubular light-emitting illuminating device may be a straight tube, or may be an annular shape such as a fluorescent lamp commonly called a circular line.

  As the substrate 1, a known substrate can be adopted as long as the transparent electrode 2 can be formed on the surface thereof. Examples of the substrate 1 include a glass substrate, a plastic sheet, a ceramic, and a metal plate obtained by processing the surface into an insulating property such as forming an insulating coating layer on the surface. When the substrate 1 is opaque, the white light emitting illumination device is a single-sided illumination device that can irradiate white light on the side opposite to the substrate 1. Moreover, when this board | substrate 1 is transparent, it is a double-sided illuminating device which can irradiate white light from the board | substrate 1 side of a white light-emitting illuminating device and the surface on the opposite side.

As the transparent electrode 2, various materials can be employed as long as they have a large work function and are transparent and can act as an anode by applying a voltage to inject holes into the light emitting layer 3. Specifically, the transparent electrode 2 is made of an inorganic transparent conductive material such as ITO, In ₂ O ₃ , SnO ₂ , ZnO, or CdO, or a compound thereof, or a conductive polymer material such as polyaniline. Can do.

  The transparent electrode 2 is formed on the substrate 1 by chemical vapor deposition, spray pyrolysis, vacuum deposition, electron beam deposition, sputtering, ion beam sputtering, ion plating, ion assisted deposition, and others. It can be formed by the method.

  When the substrate is formed of an opaque member, the electrode formed on the substrate does not need to be a transparent electrode.

  The light emitting layer 3 is a layer containing the specific white light emitting compound in this invention. The white light emitting compound will be described later. The light emitting layer 3 can be formed as a polymer film in which the specific white light emitting compound in the present invention is dispersed in a polymer, and the white light emitting compound is deposited on the transparent electrode 2. It can be formed as a deposited film.

  As the polymer in the polymer film, polyvinyl carbazole, poly (3-alkylenethiophene), polyimide containing arylamine, polyfluorine, polyphenylene vinylene, poly-α-methylstyrene, vinylcarbazole / α-methylstyrene copolymer A coalescence etc. can be mentioned. Among these, polyvinyl carbazole is preferable.

  The content of the white light-emitting compound in the polymer film is usually 0.01 to 2% by weight, preferably 0.05 to 0.5% by weight.

  The thickness of the polymer film is usually 30 to 500 nm, preferably 100 to 300 nm. If the thickness of the polymer film is too thin, the amount of emitted light may be insufficient, and if the thickness of the polymer film is too large, the driving voltage may become too high, which may be undesirable. Flexibility may be lacking when using a curved or annular body.

  The polymer film may be formed by a coating method such as a spin casting method, a coating method, a dip method, or the like, using a solution obtained by dissolving the polymer and the white light emitting compound in the present invention in an appropriate solvent. it can.

  When the said light emitting layer 3 is a vapor deposition film, the thickness of the vapor deposition film is generally 0.1-100 nm, although it changes with layer structures in a light emitting layer, etc. When the thickness of the deposited film is too small or too large, the same problem as described above may occur.

  The electrode layer 4 employs a material having a small work function, and may be formed of a single metal or a metal alloy such as MgAg, an aluminum alloy, and metal calcium. A preferred electrode layer 4 is an alloy electrode of aluminum and a small amount of lithium. The electrode layer 4 can be easily formed on the surface including the light emitting layer 3 formed on the substrate 1, for example, by a vapor deposition technique.

  Regardless of which of the coating method and the vapor deposition method is employed, it is preferable to interpose a buffer layer between the electrode layer and the light emitting layer.

  Examples of a material that can form the buffer layer include alkali metal compounds such as lithium fluoride, alkaline earth metal compounds such as magnesium fluoride, oxides such as aluminum oxide, 4,4′-biscarbazole biphenyl ( Cz-TPD). Further, as a material for forming a buffer layer formed between an anode such as ITO and an organic layer, for example, m-MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenyl Amine), phthalocyanine, polyaniline, polythiophene derivatives, inorganic oxides such as molybdenum oxide, ruthenium oxide, vanadium oxide, and lithium fluoride. By appropriately selecting the material of these buffer layers, the driving voltage of the organic EL element, which is a white light emitting lighting device, can be reduced, the quantum efficiency of light emission can be improved, and the light emission luminance can be improved. Can be achieved.

  Next, the white light emitting compound contained in the light emitting layer 3 will be described in detail.

  This white light emitting compound is a novel compound represented by the formula (1).

  All of the white light-emitting compounds represented by the formula (1) in the present invention have a quinacridone skeleton represented by the formula (3).

  The compound represented by the formula (3) is well known as a pigment called quinacridone or pigment violet 19. This quinacridone is synthesized by using, for example, diethyl succinyl succinate and aniline as main raw materials and performing, for example, condensation, ring closure, and oxidation. Quinacridone itself is excellent in fastness, weather resistance and heat resistance (“Color Material Engineering Handbook” (edited by Color Material Association, P402).

  In addition, the white light-emitting compound represented by the formula (1) in this invention has a quinacridone skeleton and a carbazole skeleton or a carbazole-like skeleton.

  Therefore, the white light-emitting compound represented by the formula (1) has a solid skeleton as a chemical structure, and thus is excellent in fastness, weather resistance, light resistance and heat resistance. The compound represented by the formula (1), which has such a quinacridone skeleton and a carbazole skeleton or a carbazole-like skeleton, is a completely novel compound having excellent light emission characteristics and structural stability.

In the formula (1), R ¹ represents a hydrogen atom, an alkyl group, an aryl group or an arylalkyl group. Examples of the alkyl group include an alkyl group having 1 to 30 carbon atoms, and a lower alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and a propyl group is particularly preferable. Two R ¹ may be the same or different. Examples of the aryl group when R ¹ is an aryl group include a phenyl group, a naphthyl group, an anthranyl group, a biphenyl group, and a group in which a substituent such as an alkyl group or an alkoxy group is bonded to these aromatic rings. . When R ¹ is an arylalkyl group, the arylalkyl group includes benzyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylpropyl group, 2-phenylpropyl group, 3-phenylpropyl group, 5-phenylbutyl group etc. can be mentioned, The phenyl group may be further substituted by substituents, such as an alkyl group. A preferred arylalkyl group is a benzyl group.

In the formula (1), two R ^{2 s} are each a hydrogen atom, an alkyl group, an aryl group, or an arylalkyl group, and may be the same group or different groups. Examples of the alkyl group include an alkyl group having 1 to 30 carbon atoms, and a lower alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and a propyl group is particularly preferable. Two R ² may be the same or different. When R ² is an aryl group, the aryl group includes a phenyl group, a naphthyl group, an anthranyl group, a biphenyl group, and a group in which a substituent such as an alkyl group and an alkoxy group is bonded to these aromatic rings, such as p-alkoxyphenyl. Groups and the like. When R ² is an arylalkyl group, the arylalkyl group includes benzyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylpropyl group, 2-phenylpropyl group, 3-phenylpropyl group, 5-phenylbutyl group etc. can be mentioned, The phenyl group may be further substituted by substituents, such as an alkyl group. A preferred arylalkyl group is a benzyl group.

In the formula (2), R ¹ has the same meaning as mentioned in the formula (1).

The white light emitting compound represented by the formula (1) has a substituent of R ¹ , R ² , R ^3, and R ⁴ , so that the solubility in a solvent is improved, and therefore, it is dissolved in an appropriate solvent. Since the coating property is improved and the sublimation temperature is lowered, the processability by vapor deposition is improved, and the compatibility with the polymer compound is improved, so that it can be included in the polymer film.

  The white light emitting compound represented by the formula (1) can be produced, for example, according to the following reaction formula.

In the above formula, R is a lower alkyl group, and R ¹ and R ² have the same meaning as described above. The above reaction formula is, for example, dialkyl 2,5-dihydroxy-1,4-cyclohexadiene-1.4-dicarboxylate (compound (4) in the above reaction formula) and 3-amino-9-alkylcarbazole. It proceeds by heating compound (5) in an appropriate solvent. The dehydration reaction proceeds to obtain a compound (6) crosslinked with an amino group. An appropriate dehydrating agent such as concentrated sulfuric acid can be used for the dehydration reaction.

  When the dehydration reaction product is further treated with concentrated sulfuric acid or the like, a dehydrogenation reaction occurs as shown in the following formula.

When R ¹ is a hydrogen atom, the dehydrogenation reaction product is reacted with, for example, R ¹ Hal (wherein Hal represents a halogen atom) in DMF. The product can be alkylated.

  Next, a ring closure reaction is performed according to the following reaction formula.

  The ring closure reaction is performed by heating in an appropriate solvent, preferably by heating in an appropriate solvent such as dichlorobenzene in the presence of an organic acid catalyst such as p-toluenesulfonic acid. ,proceed. As a ring-closed compound, there is a white light-emitting compound containing a carbazole skeleton represented by the above formula (8).

  In the above reaction formula, the compound represented by (8) is also a white light-emitting compound according to the present invention represented by the formula (1).

  The white light-emitting compound in this invention has three fluorescence spectra corresponding to red, green, and blue, respectively, by giving electromagnetic wave energy, and visible light emission over a region of 400 to 700 nm as a whole is seen. Has an emission spectrum and a fluorescence spectrum as shown in FIG. 18, and can be used for an organic EL element capable of emitting white light.

  The white light-emitting illuminating device shown in FIG. 1 that contains such a single compound and a fluorescent compound capable of emitting white light in the light-emitting layer is white when an electric current is passed through the transparent electrode 2 and the electrode layer 4. Flashes on.

  For light emission, when an electric field is applied between the transparent electrode 2 and the electrode layer 4, electrons are injected from the electrode layer 4 side, holes are injected from the transparent electrode 2, and electrons are further emitted from the light emitting layer 3. It is a phenomenon in which energy is released as light when recombining with holes and the energy level returns from the conduction band to the valence band.

  If the overall shape of the white light emitting illumination device A shown in FIG. 1 is a large area planar shape, the white light emitting illumination device A or the large area ceiling surface white light emitting illumination is mounted on, for example, a wall surface or ceiling. It can be a device. That is, the white light emitting illumination device can be used as a surface light source in place of a conventional linear light source such as a fluorescent lamp or a point light source such as a light bulb. In particular, the white light emitting illumination device can emit or illuminate a wall surface, a ceiling surface, or a floor surface such as a residential room, an office room, and a vehicle room. Further, the white light emitting illumination device A can be used as a backlight for a display screen in a computer, a display screen in a mobile phone, a numeric display screen in a cash register, and the like. In addition, the white light-emitting illumination device A can be used as various light sources such as direct illumination and indirect illumination, and can also emit light at night and has good visibility and a road sign device. , And a light-emitting bulletin board, and also a light source such as a brake lamp in a vehicle such as an automobile. Moreover, since the white light-emitting illumination device A has a white light-emitting compound having a specific chemical structure in the light-emitting layer, the light-emitting lifetime is long. Therefore, the white light emitting illumination device A can be a light source that emits light with a long lifetime.

  Further, the white light emitting illumination device A is a tubular light emitting body in which a substrate 1 formed in a cylindrical shape and a transparent electrode 2, a light emitting layer 3 and an electrode layer 4 are laminated in this order on the inner surface side of the substrate 1. be able to. Since the white light emitting illumination device A does not use mercury, it can be used as an environmentally friendly light source in place of a conventional fluorescent lamp using mercury.

  Next, the 2nd example of the white light emission illumination device concerning this invention is shown in a figure. FIG. 2 is an explanatory view showing a cross section of a white light-emitting illumination device which is a multilayer organic EL element.

  As shown in FIG. 2, the white light emitting lighting device B has a transparent electrode 2, a hole transport layer 5, light emitting layers 3 a and 3 b, an electron transport layer 6, and an electrode layer 4 stacked in this order on the surface of the substrate 1. Become.

  About the board | substrate 1, the transparent electrode 2, and the electrode layer 4, it is the same as that in the white light emission illumination device A shown by FIG.

  The light emitting layer in the white light emitting illumination device B shown in FIG. 2 includes a light emitting layer 3a and a light emitting layer 3b, and the light emitting layer 3a is a deposited film of a white light emitting compound in the present invention. The light emitting layer 3b is a DPVBi layer. This DPVBi layer is a layer having a host material function.

  Examples of the hole transport material contained in the hole transport layer 5 include triphenylamine compounds such as N, N′-diphenyl-N, N′-di (m-tolyl) -benzidine (TPD) and α-NPD. Examples thereof include hydrazone compounds, stilbene compounds, heterocyclic compounds, and π electron starburst hole transport materials.

  Examples of the electron transport material contained in the electron transport layer 6 include 2- (4-tert-butylphenyl) -5- (4-biphenyl) -1,3,4-oxaxene. Oxadiazole derivatives such as diazole and 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, and 2,5-bis (5′-tert-butyl-2′-benzoxazolyl) thiophene Etc. As the electron transporting substance, for example, a metal complex material such as a quinolinol aluminum complex (Alq3) or a benzoquinolinol beryllium complex (Bebq2) can be preferably used.

  In the white light emitting illumination device B in FIG. 2, the electron transport layer 6 contains Alq3.

  The thickness of each layer is the same as that in a conventionally known multilayer organic EL element.

  The white light-emitting illuminating device B shown in FIG. 2 operates in the same manner as the white light-emitting illuminating device A shown in FIG. Therefore, the white light-emitting illuminating device B shown in FIG. 2 has the same application as the white light-emitting illuminating device A shown in FIG.

  FIG. 3 shows a third example of the white light emitting illumination device according to the present invention. FIG. 3 is an explanatory view showing a cross section of a white light emitting illumination device which is a multilayer organic EL element.

  A white light emitting illumination device C shown in FIG. 3 is formed by laminating a transparent electrode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 8 and an electrode layer 4 in this order on the surface of a substrate 1.

  The white light-emitting illuminating device C shown in FIG.

  FIG. 4 shows another example of the white light emitting illumination device. The white light emitting illumination device D shown in FIG. 4 is formed by laminating a substrate 1, an electrode 2, a hole transport layer 5, a light emitting layer 3 and an electrode layer 4 in this order.

  In addition to the white light emitting lighting device shown in FIGS. 1 to 4, a hole transport layer containing a hole transport material between an anode that is a transparent electrode and a cathode that is an electrode layer formed on a substrate, A two-layer organic low-molecular light-emitting device obtained by laminating an electron-transporting light-emitting layer containing a white light-emitting compound according to the present invention (for example, a hole transport layer between an anode and a cathode, and a white color according to the present invention as a guest dye) A two-layer dye-doped light-emitting device in which a light-emitting compound and a light-emitting layer containing a host dye are laminated, a hole transport layer containing a hole-transporting substance between the anode and the cathode, and the white color in the present invention A two-layer organic light-emitting device obtained by laminating an electron-transporting light-emitting layer obtained by co-evaporation of a light-emitting compound and an electron-transporting material (for example, a hole transport layer and a guest dye between an anode and a cathode) In this invention A two-layer dye-doped organic light-emitting device comprising an electron-transporting light-emitting layer containing a color light-emitting compound and a host dye, a hole transport layer between the anode and the cathode, and the white light-emitting compound in the present invention A three-layer organic light-emitting device formed by laminating a light-emitting layer and an electron transport layer can be given.

  The electron-transporting light-emitting layer in this light-emitting device is usually composed of 50 to 80% polyvinyl carbazole (PVK), an electron-transporting light-emitting agent 5 to 40%, and the white light-emitting compound 0.01 to 20 according to the present invention. When formed with% (weight), white light emission occurs with high luminance.

  The light emitting layer preferably contains rubrene as a sensitizer, and particularly preferably contains rubrene and Alq3.

  The white light-emitting illuminating device using the white light-emitting compound according to the present invention can be generally used as, for example, a DC-driven organic EL element, and also as a pulse-driven organic EL element and an AC-driven organic EL element. Can also be used.

(Production Example 1)
<Dehydration reaction>
In a 1000 ml three-necked flask, 25.0 g (1.2 × 10 ⁻¹ mol) of 3-amino-9-ethylcarbazole and 15.4 g (6.0 × 10 ⁻² mol) of the compound represented by the formula (10) And 200 ml each of acetic acid and ethyl alcohol were added. The mixture was heated and stirred to 120 ° C. using a silicone oil bath and reacted for 4 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and poured into ice.

  Filter using a glass filter. The solid matter remaining in the filter was washed successively with methyl alcohol cooled to 5 ° C. and petroleum ether, and then vacuum-dried to obtain a brick-colored powder (35.2 g).

  An IR chart of the powder is shown in FIG. This brick-colored powder is represented by the following formula (11).

<Dehydrogenation reaction>
In a 1000 ml three-necked flask, 25.0 g of the powder obtained by the dehydration reaction was added, 500 ml of o-dichlorobenzene was added, 1.0 g of 95% sulfuric acid at room temperature was gradually added dropwise, and the mixture was stirred for 30 minutes. The mixture was heated and stirred up to 160 ° C. using an oil bath and reacted for 2 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and poured into ice.

  Chloroform extraction was carried out 3 times using a separatory funnel, followed by washing with water twice, and then sodium sulfate was added to remove the water, followed by filtration and concentration to dryness using an evaporator. The obtained solid was sequentially washed with ethyl acetate and petroleum ether, and then vacuum-dried to obtain a red powder (13.1 g).

  The IR chart of this red powder is shown in FIG. 6, and the NMR chart is shown in FIG. This red powder is represented by the following formula (12).

<Ring ring reaction>
In a 500 ml three-necked flask, 10.0 g (1.6 × 10 ⁻² mol) of the red powder is added, and 13.7 g (7.2 × 10 ⁻² mol) of p-toluenesulfonic acid hydrate is added. Furthermore, 200 ml of O-dichlorobenzene was added. The mixture was heated and stirred to 160 ° C. using a silicone oil bath and reacted for 20 hours. After completion of the reaction, the mixture was concentrated to dryness using an evaporator. The obtained solid was sequentially washed with methyl alcohol, acetone, and petroleum ether cooled to 5 ° C., and then dried in vacuo to obtain a brown powder (9.4 g). To purify, add 700 ml of xylene to 1000 ml Meyer, add 2.0 g of the resulting brown powder and 2.0 g of activated carbon, boil for 3 minutes using a mantle heater, and concentrate the filtrate filtered while hot using an evaporator. Allowed to dry.

  The obtained solid was washed with petroleum ether and then vacuum dried to obtain a maroon powder. The IR chart of this maroon powder is shown in FIG. 8, and the NMR chart is shown in FIG.

  This maroon powder has a structural formula represented by the following formula (1a).

Example 1
In a 5 ml volumetric flask, 70 mg of polyvinylcarbazole, 29.7 mg of t-butylphenyl-diphenyl-1,3,4-oxadiazole (PBD), and a maroon powder obtained in Preparation Example 1 (compound (1a )) 0.3 mg was weighed and dichloroethane was added to prepare a white light emitting compound-containing solution to 5 ml. This white light emitting compound-containing solution was made sufficiently uniform by irradiating ultrasonic waves with an ultrasonic cleaner (US-2, manufactured by SND Corporation) for 20 minutes. An ITO substrate (50 × 50 mm, ITO transparent electrode thickness 200 μm, Sanyo Vacuum Industries Co., Ltd.) was ultrasonically cleaned with acetone for 10 minutes, then ultrasonically cleaned with 2-propanol for 10 minutes, blown with nitrogen and dried. I let you. Then, it was cleaned by UV irradiation for 30 seconds with a UV irradiation apparatus (manufactured by M.D. Excimer, wavelength 172 nm). The prepared white light-emitting compound-containing solution is dropped onto an ITO substrate that has been washed and dried using a spin coater (Mikasa Co., Ltd., 1H-D7) at a rotation speed of 1,500 rpm and a rotation time of 3 seconds. And spin-coated to form a film having a dry thickness of 100 μm. The substrate thus formed was dried in a constant temperature bath at 50 ° C. for 30 minutes, and then an aluminum alloy (Al: Li = 99: with a vacuum vapor deposition apparatus (VDS-M2-46 type, manufactured by Daia Vacuum Engineering Co., Ltd.)). 1 weight ratio, manufactured by Kojundo Chemical Laboratory Co., Ltd.) electrode was vapor-deposited at 4 × 10 ⁻⁶ Torr to a thickness of about 150 nm to produce a white light-emitting illuminating device having the structure shown in FIG.

This white light-emitting illuminating device measured luminance and chromaticity while gradually increasing the voltage with BM-7 Fast manufactured by Topcon Corporation. As a result, a result was obtained in which the voltage was 24 V, the current was 32.8 mA, the luminance was 2,100 Cd / m ² , the chromaticity X was 0.35, and the chromaticity Y was 0.34.

<Luminescent characteristics>
A sample solution was prepared by dissolving the white light-emitting compound (1a) in mixed xylene to a concentration of 10 mg / L. This sample solution was loaded into an F-4500 type spectrofluorometer manufactured by Shimadzu Corporation, and the fluorescence spectrum was measured under the following conditions. The obtained fluorescence spectrum is shown in FIG.

Measurement conditions Measurement mode Wavelength scan Excitation wavelength 365nm
Fluorescence start wavelength 400nm
Fluorescence end wavelength 700nm
Scanning speed 1200nm / min Excitation side slit 5.0nm
Fluorescent side slit 5.0nm
Photomultiplier voltage 700V
As can be seen from FIG. 10, the white light-emitting compound obtained in this example exhibits fluorescence emission of 400 to 700 nm and covers the entire region.

(Production Example 2)
<Benzylation reaction>
In a 500 ml pressure bottle, 10.0 g (1.6 × 10 ⁻² mol) of the compound having the structure represented by the same formula (12) produced in Production Example 1 was placed, and 17.1 g (7 .6 × 10 ⁻² mol) was added, and then 200 ml of N, N-dimethylformamide (DMF) was added. Using a silicone oil bath, the inside of the pressure bottle was heated to 150 ° C. with stirring and reacted for 20 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, concentrated using an evaporator, poured into ice water, and neutralized with sodium hydroxide. Chloroform extraction was performed 3 times using a separatory funnel, and water washing was performed twice. Next, sodium sulfate was added to remove moisture, filtered, and concentrated to dryness using an evaporator. The obtained solid was washed with petroleum ether and then vacuum dried to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown powder has a structure represented by formula (16).

<Ring ring reaction>
A 500 ml three-necked flask is charged with 5.0 g (6.1 × 10 ⁻³ mol) of a ring-closing compound represented by the above formula (16), and 5.2 g (2.7 × 10) of p-toluenesulfonic acid monohydrate. ^-2 mol) and 200 ml of o-dichlorobenzene was added. The mixture was heated to 160 ° C. with a silicone oil bath and reacted for 20 hours. After completion of the reaction, the mixture was concentrated to dryness using an evaporator. The obtained solid was washed with methyl alcohol, acetone and petroleum ether cooled to 5 ° C., and then vacuum-dried to obtain a brown solid.

  Using a Soxhlet extraction apparatus, 1.0 g of the brown solid was extracted with 250 ml of xylene over 24 hours. After completion of extraction, the mixture was concentrated to dryness using an evaporator, and the resulting solid was washed with petroleum ether and dried in vacuo to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown solid was a compound having a structure represented by the formula (1b).

(Example 2)
As in Example 1, “Into a 5 ml volumetric flask, 70 mg of polyvinylcarbazole, 29.7 mg of t-butylphenyl-diphenyl-1,3,4-oxadiazole, and the maroon powder (compound (1a) ) Instead of preparing a white luminescent compound-containing solution so that 0.3 mg is weighed and adding dichloroethane to 5 ml ”, 70 mg of polyvinylcarbazole and BND having the structure represented by formula (17) are added to a 5 ml volumetric flask. A white light emitting compound-containing solution was prepared by adding dichloroethane to 29.7 mg and 0.3 mg of the white light emitting compound represented by the formula (1b) to 5 ml. Using this white light-emitting compound-containing solution, a white light-emitting illuminating device having the structure shown in FIG. 1 was produced in the same manner as in Example 1, and a spectral radiometer manufactured by Topcon Co., Ltd. was manufactured for this white light-emitting illuminating device. The brightness and chromaticity were measured with SR-3.

As a result, a voltage of 21 V, current of 35.3 mA, luminance of 2,200 Cd / m ² , chromaticity X of 0.32, and chromaticity Y of 0.36 were obtained. Further, FIG. 13 shows a spectral radiance graph of this white luminescent compound with this spectroradiometer. From this spectral radiance graph, it can be recognized that white light was sufficiently emitted by the naked eye.

(Example 3)
An ITO substrate (50 × 50 mm, ITO transparent electrode layer thickness 200 nm, Sanyo Vacuum Industry Co., Ltd.) was ultrasonically cleaned with acetone for 10 minutes, then ultrasonically cleaned with 2-propanol for 10 minutes, and blown with nitrogen And dried. Thereafter, UV irradiation was performed with a UV irradiation apparatus (manufactured by M.D. Excimer, wavelength 172 nm) for 30 seconds to complete the cleaning of the ITO substrate.

The cleaned ITO substrate was set in a vacuum deposition apparatus (manufactured by Daia Vacuum Giken Co., Ltd., UDS-M2-46 type), and N, N′-diphenyl-N, N, under reduced pressure of 4 × 10 ⁻⁶ torr or less. N-di (m-tolyl) -benzidine (TPD) was vapor-deposited to a thickness of 63 nm, then the white light emitting compound (1b) was vapor-deposited to a thickness of 0.5 nm, and further represented by the following formula (18): DPVBi having a structure of 35 nm is vapor-deposited to a thickness of 35 nm, finally tris (8-quinolinato) aluminum (Alq3) is vapor-deposited to a thickness of 150 nm, and finally an aluminum alloy electrode (Al: Li = 99: 1 weight ratio) The white light emitting lighting device shown in FIG. 2 was manufactured by evaporating a high purity chemical laboratory) to a thickness of 150 nm.

  The brightness and chromaticity of this white light emitting illumination device were measured in the same manner as in Example 1.

As a result, a voltage of 16 V, current of 23.2 mA, luminance of 5500 Cd / m ² , chromaticity X of 0.31 and chromaticity Y of 0.34 were obtained. Further, FIG. 14 shows a spectral radiance graph of this white luminescent compound with this spectroradiometer. From this spectral radiance graph, it can be recognized that white light was sufficiently emitted by the naked eye.

Example 4
N, N′-diphenyl-N, N-di (m-tolyl) -benzidine (TPD) was evaporated to a thickness of 59 nm, then the white light emitting compound (1b) was evaporated to a thickness of 0.7 nm, A white light-emitting illuminating device having the structure shown in FIG. 3 was manufactured in the same manner as in Example 3 except that DPVBi having the structure represented by the formula (18) was deposited to a thickness of 36 nm. The light emission characteristics were measured in the same manner as in Example 3. As a result, the voltage was 20 V, the current was 31.2 mA, the luminance was 3100 Cd / m ² , the chromaticity X was 0.33, and the chromaticity Y was 0.34. It was.

(Example 5)
An ITO transparent electrode having a thickness of 200 nm was formed on a transparent polyester film substrate having a thickness of 188 μm by vapor deposition, and α-NPD (di- (naphtyl-phenylamino) diphenyl) 66 nm was formed on the transparent electrode by vapor deposition. A deposited layer of 0.3 nm, a DPVBi layer of 40 nm, and an Alq3 layer of 40 nm are laminated in this order, and an aluminum alloy electrode (Al: Li = 99: 1 weight ratio, manufactured by Kojundo Chemical Laboratory Co., Ltd.) is further formed thereon. The white light emitting lighting device having a laminated structure shown in FIG. 2 was manufactured. In addition, the light emitting layer 3 in FIG. 2 is formed of the vapor-deposited layer of the white light emitting compound (1b) and the DPVBi layer.

When the emission characteristics were measured in the same manner as in Example 3, the result was that the voltage was 16 V, the current was 22.6 mA, the luminance was 7500 Cd / m ² , the chromaticity X was 0.30, and the chromaticity Y was 0.37. It was.

(Example 6)
Except that the TPD layer 64 nm, the white light emitting compound (1a) 0.6 nm, the DPVBi layer 35 nm, and the Alq3 layer 38 nm are stacked in this order, it has the same stacked structure as shown in FIG. A white light emitting lighting device was manufactured. In addition, the light emitting layer 3 in FIG. 2 is formed of the vapor deposition layer of the white light emitting compound (1a) and the DPVBi layer.

The light emission characteristics were measured in the same manner as in Example 3. As a result, the voltage was 14 V, the current was 27.9 mA, the luminance was 5100 Cd / m ² , the chromaticity X was 0.30, and the chromaticity Y was 0.33. It was.

(Production Example 3)
<Methylbenzylation reaction>
10.0 g (1.6 × 10 ⁻² mol) of the compound having the structure represented by the same formula (12) as produced in Production Example 1 was placed in a 500 ml pressure bottle, and α-chloro-p-xylene An additional 15.8 g (1.1 × 10 ⁻¹ mol) was added followed by 200 ml N, N-dimethylformamide (DMF). Using a silicone oil bath, the inside of the pressure bottle was heated to 150 ° C. with stirring and reacted for 20 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, concentrated using an evaporator, poured into ice water, and neutralized with sodium hydroxide. Chloroform extraction was performed 3 times using a separatory funnel, and water washing was performed twice. Next, sodium sulfate was added to remove moisture, filtered, and concentrated to dryness using an evaporator. The obtained solid was washed with petroleum ether and then vacuum dried to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown powder has a structure represented by the formula (19).

<Ring ring reaction>
A 500 ml three-necked flask is charged with 5.0 g (5.4 × 10 ⁻³ mol) of a ring-closing compound represented by the above formula (19), and 8.0 g (4.1 × 10 10) of p-toluenesulfonic acid monohydrate. ^-2 mol) and 200 ml of o-dichlorobenzene was added. The mixture was heated to 160 ° C. with a silicone oil bath and reacted for 20 hours. After completion of the reaction, the mixture was concentrated to dryness using an evaporator. The obtained solid was washed with methyl alcohol, acetone and petroleum ether cooled to 5 ° C., and then vacuum-dried to obtain a brown solid.

  Using a Soxhlet extraction apparatus, 1.0 g of the brown solid was extracted with 250 ml of xylene over 24 hours. After completion of extraction, the mixture was concentrated to dryness using an evaporator, and the resulting solid was washed with petroleum ether and dried in vacuo to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown solid was a compound having a structure represented by the formula (1c).

(Example 7)
The same as Example 3 except that an α-NPD layer 45 nm, a layer 18 nm obtained by doping 4.4% of the white light emitting compound (1c) shown in Production Example 3 into DPVBi, and an Alq3 layer 21 nm were laminated in this order. Thus, a white light emitting lighting device having the same laminated structure as shown in FIG. 3 was manufactured.

When the emission characteristics were measured in the same manner as in Example 3, the result was that the luminance was 10720 Cd / m ² at a voltage of 18 V and a current of 30.9 mA, the chromaticity X was 0.35, and the chromaticity Y was 0.39. It was.

(Example 8)
An α-NPD layer of 46 nm, a layer 31 nm obtained by doping 2.9% of the white light-emitting compound (1c) into CBP having a structure represented by the formula (20), and an Alq ₃ layer 19 nm were stacked in this order except that In the same manner as in Example 3, a white light-emitting illuminating device having a stacked structure similar to that shown in FIG.

When the emission characteristics were measured in the same manner as in Example 3, the result was that the voltage was 17 V, the current was 36.1 mA, the luminance was 10120 Cd / m ² , the chromaticity X was 0.32, and the chromaticity Y was 0.35. It was.

(Production Example 4)
<Methylation reaction>
10.0 g (1.6 × 10 ⁻² mol) of the compound having the structure represented by the same formula (12) as that produced in Production Example 1 was put in a 500 ml pressure bottle, and 10.8 g (7. 6 × 10 ⁻² mol) was added, followed by 200 ml of N, N-dimethylformamide (DMF). Using a silicone oil bath, the inside of the pressure bottle was heated to 150 ° C. with stirring and reacted for 20 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, concentrated using an evaporator, poured into ice water, and neutralized with sodium hydroxide. Chloroform extraction was performed 3 times using a separatory funnel, and water washing was performed twice. Next, sodium sulfate was added to remove moisture, filtered, and concentrated to dryness using an evaporator. The obtained solid was washed with petroleum ether and then vacuum dried to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown powder has a structure represented by the formula (21).

<Ring ring reaction>
In a 500 ml three-necked flask, 5.0 g (7.5 × 10 ⁻³ mol) of a ring-closing compound represented by the above formula (20) was added, and 8.0 g (4.2 × 10) of p-toluenesulfonic acid monohydrate. ^-2 mol) and 200 ml of o-dichlorobenzene was added. The mixture was heated to 160 ° C. with a silicone oil bath and reacted for 20 hours. After completion of the reaction, the mixture was concentrated to dryness using an evaporator. The obtained solid was washed with methyl alcohol, acetone and petroleum ether cooled to 5 ° C., and then vacuum-dried to obtain a brown solid.

  Using a Soxhlet extraction apparatus, 1.0 g of the brown solid was extracted with 250 ml of xylene over 24 hours. After completion of extraction, the mixture was concentrated to dryness using an evaporator, and the resulting solid was washed with petroleum ether and dried in vacuo to obtain a brown powder. An IR chart of this brown powder is shown in FIG. This brown solid was a compound having a structure represented by the formula (1d).

Example 9
<Luminescent characteristics>
In the same manner as in the above <light emission characteristics>, TPD was vapor-deposited to a thickness of 71 nm on the ITO substrate, then the white light-emitting compound (1d) was vapor-deposited to a thickness of 0.6 nm, and further DPVBi was 40 nm. Finally, tris (8-quinolinato) aluminum (Alq3) was evaporated to a thickness of 41 nm, and finally an aluminum alloy electrode (Al: Li = 99: 1 weight ratio, high purity chemical research) The EL device was manufactured by vapor-depositing the product to a thickness of 150 nm.

  The luminance and chromaticity of this EL element were measured.

As a result, a voltage of 16 V, a current of 17.5 mA, a luminance of 5000 Cd / m ² , a chromaticity X of 0.36, and a chromaticity Y of 0.37 were obtained. Further, FIG. 17 shows a spectral radiance graph of this white light-emitting compound with this spectroradiometer. From this spectral radiance graph, it can be recognized that white light was sufficiently emitted by the naked eye.

FIG. 1 is an explanatory view showing a laminated structure of a white light emitting illumination device as an example of the present invention. FIG. 2 is an explanatory view showing a laminated structure of a white light emitting illumination device as another example of the present invention. FIG. 3 is an explanatory view showing a laminated structure of a white light emitting illumination device as another example of the present invention. FIG. 4 is an explanatory view showing a laminated structure of a white light emitting illumination device which is still another example of the present invention. FIG. 5 is an IR chart showing compounds obtained by dehydrating dimethyl 1,4-cyclohexanedione-2,5-dicarboxylate and 3-amino-9-ethylcarbazole in Production Example 1. FIG. 6 is an IR chart showing a ring-closing compound obtained by subjecting a dehydration reaction product to a ring-closing reaction in Production Example 1. FIG. 7 is an NMR chart showing the closed compound in Production Example 1. FIG. 8 is an IR chart showing a white light-emitting compound obtained by dehydrogenating a ring-closing compound in Production Example 1. FIG. 9 is an NMR chart showing the white light-emitting compound in Production Example 1. FIG. 10 is a graph showing the fluorescence spectrum of the white light-emitting compound in Production Example 1. FIG. 11 is an IR chart of a compound having the structure of formula (16). FIG. 12 is an IR chart of a compound having the structure of formula (1b). FIG. 13 is a spectral radiance graph showing light emission characteristics of an organic EL device using a compound having the structure of formula (1b). FIG. 14 is a spectral radiance graph showing the emission characteristics of an organic EL device using a compound having the structure of formula (1b). FIG. 15 is an IR chart of the compound having the structure of formula (21). FIG. 16 is an IR chart of a compound having the structure of formula (1d). FIG. 17 is a spectral radiance graph showing light emission characteristics of an organic EL device using a compound having the structure of the formula (1d). FIG. 18 is a spectrum chart showing a typical emission spectrum and fluorescence spectrum of the white light-emitting compound in the present invention. FIG. 19 is an IR chart of the compound having the structure of formula (19). FIG. 20 is an IR chart of the compound having the structure of formula (1c).

Explanation of symbols

A, B, C: white light emitting illumination device, 1 ... substrate, 2 ... transparent electrode, 3 ... light emitting layer, 4 ... electrode layer.

Claims (7)

A white light emitting illumination device comprising a light emitting layer containing a light emitting material on a substrate on which an electrode is formed, wherein the light emitting material is a white light emitting compound represented by the formula (1). White light-emitting illuminator with compound.

(However, R ¹ represents a hydrogen atom, an alkyl group, an aryl group, or an arylalkyl group. R ² represents a hydrogen atom, an alkyl group, an aryl group, or an arylalkyl group.)   The white light emitting illumination device using the single compound is a single-layer organic EL element having the substrate and a light emitting layer containing the white light emitting compound represented by the formula (1) provided on the substrate. The white light-emitting illuminating device with a single compound according to claim 1.   The white light emitting illumination device includes a hole transport layer, a light emitting layer containing a white light emitting compound represented by the formula (1), and an electron transport layer provided on the substrate, laminated on the transparent substrate. The white light emitting illumination device with a single compound according to claim 1, which is a multilayer organic EL device.   The white light emitting illumination device according to any one of claims 1 to 3, wherein the light emitting layer is a layer formed by dispersing the white light emitting compound in a polymer.   The white light emitting illumination device according to any one of claims 1 to 3, wherein the light emitting layer is a layer formed by depositing the white light emitting compound on the substrate.   The white light emitting illumination device according to claim 1, wherein the white light emitting illumination device is a planar light emitting illumination device or a tubular light emitting illumination device.   A white light-emitting organic EL device comprising a light-emitting layer containing a light-emitting material on a substrate on which an electrode is formed, wherein the light-emitting material is a white light-emitting compound represented by the formula (1). White light-emitting organic EL device using one compound.

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