JP2022115839A - Organic electroluminescence element and organic electroluminescence lighting using novel 1,10-phenanthroline compound - Google Patents

Abstract

To provide an organic electroluminescence element using a novel compound that has excellent heat resistance, high efficiency, low voltage, and long life, contribute to high performance phosphorescent or thermally activated organic EL devices using triplet excitons, and provide organic electroluminescence lighting using the same.SOLUTION: 1,10-phenanthroline compounds indicated formulas 1 and 2 are provided.SELECTED DRAWING: Figure 1

Description

The present invention provides an organic electroluminescence device using a novel 1,10-phenanthroline compound that is excellent in heat resistance, has good compatibility with a deep red dye, and realizes high efficiency, low voltage and long life of the device. The present invention contributes to the improvement of the performance of phosphorescent or thermally activated organic EL devices using triplet excitons, and relates to organic electroluminescence lighting using the same.

Organic electroluminescence has started to be put to practical use in new flat-panel TVs that will replace LCD TVs (for example, Sony Bravia website (https://www.sony.jp/bravia/ )), next-generation displays compatible with large projectors that support 4K and 8K, and displays in the medical field that require high definition (for example, the JOELD website (https://www.j-oled.com/application/ )), and is also expected to be applied to lighting. In fact, in recent years organic electroluminescence has become popular not only for televisions but also for displays for large projectors and light sources for lighting. .

The important ones are smooth surface morphology, suitable highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) levels, and high charge injection and transport properties. In particular, electron-transporting (n-type) organic semiconductors are known to have three orders of magnitude lower mobility than hole-transporting (p-type) organic semiconductors used for organic electroluminescence. (For example, Non-Patent Documents 1 and 2)

Disadvantages of the different mobilities include that the holes and electrons injected from the two electrodes cannot be efficiently combined, and charges accumulate at the interface of the organic film in the fabricated device, resulting in a decrease in luminous efficiency. During the recombination of electric charges, abnormal heat is generated from the element because it is converted into heat energy instead of being converted into light emission energy. Crystallization causes the formation of quenching parts called dark spots, the organic compound itself is destroyed by the heat generation itself, or the accumulated electric charge causes the organic compound to undergo an oxidation or reduction reaction, which is similar to thermal destruction of the organic compound. is changed to another compound.
All of these adverse effects are known to seriously affect the life of the device. (For example, Non-Patent Document 3)

As a method of avoiding this adverse effect, in organic electroluminescence, it is common to adopt a multi-layer laminated structure in which functions are separated. The function of this functional separation means hole injection, hole transport, light emission, electron transport and electron injection, and in some cases each function is independently independent, and one layer takes charge of any two or more functions. In some cases. In some cases, one function includes one type of organic compound, and in some cases, one function constitutes a hybrid with two or more organic compounds or, in some cases, inorganic compounds. (For example, Non-Patent Document 4) Furthermore, a tandem structure in which many layers of these functions are laminated may be adopted. (Patent document 1)

As for the organic electroluminescence (hereinafter abbreviated as organic EL) currently on the market, in mobile terminals such as smartphones and organic EL televisions, almost all of them apply the technology of functionally dispersed elements or tandem elements. An organic EL panel is used.

An organic EL panel manufactured by such a technique can vapor-deposit light-emitting materials of blue, green, and red, which are the three primary colors of light, using a shadow mask, or emit light based on white from the three primary colors. It is full-color with blue, green, and red color filters. (For example, Non-Patent Document 5)

In the field of lighting, organic EL panels have been adopted in fields such as indirect lighting, and some have achieved an internal quantum efficiency of 100% in combination with phosphorescent materials and are used as energy-saving lighting. (For example, Non-Patent Document 6)

As a light source, it is important not only for domestic use and industrial use but also in primary industries such as agriculture. In the field of agriculture, lighting is used as a light source for greenhouse cultivation and artificial cultivation in highly airtight rooms. In particular, high-efficiency organic EL that emits light in the deep red region around a wavelength of 670 nm is used as a light source for growing plants. Application is expected.

Although there are many good aspects of the currently used functional separation elements, there are, of course, some aspects that require improvement. That is, the number of vapor deposition or coating is increased to separate the functions. Needless to say, an increase in the number of times increases the labor involved in fabricating the element or display. In this case, labor means the time required for manufacturing. Requiring more time means a decrease in the number of light-emitting elements manufactured per unit time. A reduction in the number of sheets to be produced will push up the production cost per unit. Moreover, since the number of materials used increases, the material cost also increases. These effects are also reflected in the selling price of the final product.

Considering the above, it is necessary to separate functions, but in order to compete with liquid crystal (LCD) panels and light emitting diode (LED) panels, the parts that can be combined as functions should be combined to simplify the production of elements or displays. is required.

Abhishek P.; Kulkarni, Christopher J.; Tonzola, Amit Babel, and Samson A Jenekhe. , Chem. Mater. 2004, 16, 4556 Lixin Xiao, Zhijian Chen, Bo Qu, Jiaxiu Luo, Sheng Kong, Qihuang Gong and Junji Kido, Adv. Mater. 2011, 23, 926 Tatsuo Mori, "Material design and long-life technology for organic EL devices", Surface technology, Vol.61, No.10, 2011, p.682 Akiyoshi Mikami "Fundamentals of Organic EL Display" Journal of the Institute of Image Information and Television Engineers, Vol.67, No.9, pp.800, 2013 Electronic Device Industry News September 28, 2018, "268th LG's 8K Organic EL, Challenges for Higher Definition," https://www.sangyo-times.jp/article.aspx? ID=2764 ITmedia, March 6, 2014, "Overtake LED lighting or achieve 131 lumens/watt with 'organic EL'," https://www. it media. co. jp. /smartjapan/articles/1403/06/news036. html

Japanese Patent No. 4925569

An object of the present invention is to provide an element that can achieve both long life, low power consumption, and efficient manufacturing, and a light emitting element including a deep red light emitting element that is difficult to achieve both improved luminous efficiency and long life. There is a point to do.

〔式中、Ｒ^１は水素またはメチル基、エチル基、ノルマルプロピル基およびイソプロピル基よりなる群からそれぞれ独立して選ばれた基である。〕
で示された１，１０‐フェナントロリン化合物類を含有する有機エレクトロルミネッセンス素子。
２）下記一般式〔２〕

〔式中、Ｒ^２は水素またはメチル基、エチル基、ノルマルプロピル基およびイソプロピル基よりなる群からそれぞれ独立して選ばれた基である。〕
で示された１，１０‐フェナントロリン化合物類を含有する有機エレクトロルミネッセンス素子。
３）１）記載の１，１０‐フェナントロリン化合物類を電子輸送層及び／又は発光層に用いた有機エレクトロルミネッセンス素子。
４）２）記載の１，１０‐フェナントロリン化合物類を電子輸送層及び／又は発光層に用いた有機エレクトロルミネッセンス素子。
５）３）記載の有機エレクトロルミネッセンス素子を用いた有機エレクトロルミネッセンス照明。
６）４）記載の有機エレクトロルミネッセンス素子を用いた有機エレクトロルミネッセンス照明。
７）３）記載の有機エレクトロルミネッセンス素子を用いた深赤色有機エレクトロルミネッセンス照明。
８）４）記載の有機エレクトロルミネッセンス素子を用いた深赤色有機エレクトロルミネッセンス照明。 The above problems are solved by the following inventions 1) to 6).
1) the following general formula [1]

[In the formula, R ¹ is hydrogen or a group independently selected from the group consisting of a methyl group, an ethyl group, a normal propyl group and an isopropyl group. ]
An organic electroluminescence device containing 1,10-phenanthroline compounds represented by
2) the following general formula [2]

[In the formula, R ² is hydrogen or a group independently selected from the group consisting of a methyl group, an ethyl group, a normal propyl group and an isopropyl group. ]
An organic electroluminescence device containing 1,10-phenanthroline compounds represented by
3) An organic electroluminescence device using the 1,10-phenanthroline compounds described in 1) for an electron-transporting layer and/or a light-emitting layer.
4) An organic electroluminescence device using the 1,10-phenanthroline compounds described in 2) for an electron-transporting layer and/or a light-emitting layer.
5) Organic electroluminescence lighting using the organic electroluminescence device described in 3).
6) Organic electroluminescence lighting using the organic electroluminescence device described in 4).
7) Deep red organic electroluminescence illumination using the organic electroluminescence device described in 3).
8) Deep red organic electroluminescence illumination using the organic electroluminescence device described in 4).

According to the organic electroluminescence device using new phenanthroline compounds in which 6-quinoline compound and 4-isoquinoline compound, which are heteroaryl ring compounds, are introduced at the 2- and 9-positions of the 1,10-phenanthroline compound of the present invention , it is possible to provide an element that achieves both long life, low power consumption, and efficient manufacturing. In addition, since it has the ability to make a deep red light emitting material emit light efficiently, it can be applied to deep red lighting.
In the density functional theory calculation, the compounds invented this time are 2,9-di-2-naphthalenyl-4,7-diphenyl-1,10-phenanthrene (hereinafter abbreviated as NBPhen), which is conventionally used as an electron transport material. Since the lowest unoccupied molecular molecular orbital (LUMO) level is deeper than the lowest unoccupied molecular molecular orbital (LUMO) level value of -2.16 eV, improvement in electron injection is expected. In fact, electron injection from the cathode electrode is easy because the experimentally determined electron affinity is -3.6 eV, which is close to the work function of the electrode used for the cathode, such as aluminum metal, -4.1 eV. .
As for the heat resistance required for organic electroluminescence materials, the 1,10-phenanthroline compound of the present invention can sufficiently withstand the heat generated in the device because the glass transition temperature is 130° C. or higher, and Hardly denatured by heat.
In addition, due to its excellent electrochemical stability, it has a longer lifetime than the conventional material NBphen at a luminance of 1000 cd/m ² when combined with a green light-emitting material. When combined with a deep red light-emitting material, the effect of confining energy inside is high, so that energy is not leaked to surrounding materials and red light emission with high color purity can be obtained.
Further, by using the 1,10-phenanthroline compound of the present invention, which hardly causes crystallization, conventional organic electroluminescence devices can be easily produced, which contributes to time and economic effects.
Therefore, the present invention is considered to be extremely useful as an industrially applicable invention.

An example of the device produced in Example 1 is shown in FIG. Energy diagrams of 4iq-Bphen, 6q-Bphen and 3q-Bphen of Example 1 on each element are shown in FIG. FIG. 3 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and 3q-Bphen of Example 1 to which NBphen was added. The current density-voltage characteristics of Example 1 are shown in FIG. The luminance-voltage characteristics of Example 1 are shown in FIG. The power efficiency-luminance characteristics of Example 1 are shown in FIG. FIG. 7 shows the external quantum efficiency-luminance characteristics of Example 1. In FIG. FIG. 8 shows the driving life (half life) measurement of Example 1. FIG. An example of the device produced in Example 2 is shown in FIG. FIG. 10 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and 3q-Bphen of Example 2 with NBphen added thereto. The current density-voltage characteristics of Example 2 are shown in FIG. The luminance-voltage characteristics of Example 2 are shown in FIG. The power efficiency-luminance characteristics of Example 2 are shown in FIG. FIG. 14 shows the external quantum efficiency-luminance characteristics of Example 2. In FIG. FIG. 15 shows the driving life (half life) measurement of Example 2. FIG. FIG. 16 shows energy diagrams of 4iq-Bphen, 6q-Bphen and 3q-Bphen of the device fabricated in Example 3 on each device. FIG. 17 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and 3q-Bphen of Example 3, respectively. The current density-voltage characteristics of Example 3 are shown in FIG. The luminance-voltage characteristics of Example 3 are shown in FIG. FIG. 20 shows the external quantum efficiency-luminance characteristics of Example 3. FIG. 21 shows the driving life (half life) measurement of Example 3. FIG. FIG. 22 shows an EL spectrum showing light emission from the device using 4iq-Bphen, 6q-Bphen, and 4DBT46TRZ of the device fabricated in Example 4. FIG. The current density-voltage characteristics of Example 4 are shown in FIG. The luminance-voltage characteristics of Example 4 are shown in FIG. FIG. 25 shows the external quantum efficiency-luminance characteristics of Example 4. FIG. FIG. 26 shows the driving life (half life) measurement of Example 4. FIG. FIG. 27 shows a cross-sectional view of a preferred example of the organic EL device of the present invention.

The present invention will be described in detail below.
The novel 1,10-phenanthroline compound of the present invention can be produced by Suzuki-Miyaura coupling (hereinafter abbreviated as Suzuki coupling). The reaction formula is shown below.

In the case of general formula [1]

In the case of general formula [2]

も脱離基として作用するため、Ｘ^１がこのような置換基を付加したような化合物でも同様に本反応で使用することができる。 X ¹ in the above production methods of general formulas [1] and [2] represents a halogen atom, such as chlorine, bromine or iodine. In some cases, trifluoromethanesulfonate

also acts as a leaving group, a compound in which such ^a substituent is added to X1 can also be used in this reaction.

あるいはホウ酸エステル

などを表す。Ｒ^１’およびＲ^２’は、メチル基やイソプロピル基などのアルキル基であり、Ｒ^１’およびＲ^２’が一緒になって環を形成していても良い。 For X ² in the above production method of general formula [1] and general formula [2], a boric acid compound

or boric acid ester

and so on. R ^1' and R ^2' are alkyl groups such as a methyl group and an isopropyl group, and R ^1' and R ^2' may together form a ring.

Solvents include aromatic hydrocarbons such as toluene, xylene and mesitylene, cyclic ethers such as tetrahydrofuran, 1,4-dioxane, aliphatic ethers such as 1,2-dimethoxyethane, ethylene glycol monomethyl ether, or ethanol. , isopropyl alcohol, n-butanol, and the like can be used. These solvents may be used singly or in combination of two or more.

As for the base used in the reaction, an alkali metal carbonate, phosphate, or the like can be used. Examples include sodium carbonate, potassium carbonate, cesium carbonate, tertiary potassium phosphate, dibasic potassium phosphate, tertiary sodium phosphate, and dibasic sodium phosphate. These are usually used singly, but there is no problem even if they are used in combination of two or more kinds of bases.

As for the catalyst, a palladium-based catalyst is used. Since the reaction is difficult to proceed with palladium alone, it is preferable to use a phosphorus co-catalyst together. Tetrakis(triphenylphosphine)palladium can be exemplified as palladium that can be used alone. This is a complex compound of palladium and triphenylphosphine.
Examples of palladium catalysts that can be used in combination with a phosphorus catalyst include palladium acetate, palladium chloride, trisbenzylideneacetone dipalladium and bisbenzylideneacetone palladium.
Phosphorus catalysts used in combination include triphenylphosphine, triorthotolylphosphine, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (X-phos), 2-dicyclohexylphosphino-2′,6 '-dimethoxybiphenyl (S-phos), 2-dicyclohexylphosphino-2'-dimethylaminobiphenyl (Davephos), 2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl (Ruphos), tricyclohexylphosphine, etc. can be exemplified.

Water is not absolutely necessary and the reaction may be run anhydrous. When added, it is added in an amount of about 1/2 to 1/3 of the amount of the organic solvent used.

The reaction temperature is usually the temperature at which the solvent is refluxed.

The reaction time is determined while tracking the progress of the reaction with equipment such as gas chromatogram, high performance liquid chromatogram, or thin layer chromatogram.

The starting material, 2,9-dichloro-4,7-diphenyl-1,10-phenanthroline, is commercially available.

The other raw materials, 4-isoquinolineboronic acids and 6-quinolineboronic acids, are also available as industrial products.

If it is not available, the boronic acid can be obtained by converting the corresponding halide into a Grignard reagent or lithium reagent, reacting it with trimethylborane or triisopropylborane, and hydrolyzing it with acidic water such as hydrochloric acid.

If the boronate ester is desired, treatment with water in the reaction of [0031] will give the corresponding methyl ester or isopropyl ester. A cyclic ester of pinacol can be obtained by subjecting the boronic acid obtained in [0031] to dehydration condensation with pinacol in toluene. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane and Grignard or lithium reagents synthesized in [0031], and further reaction with the corresponding halide and bispin A cyclic boronic acid can also be obtained by adding a catalyst such as [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride and heating colatodiborane in the presence of potassium acetate in an appropriate solvent such as dimethylformamide. can be done.

The 1,10-phenanthroline compound obtained by the reaction has a problem in purity, so it is necessary to purify it before making it into a device. Recrystallization is effective for purification, but silica gel column chromatography can also be used in some cases.

The purified 1,10-phenanthroline compound is desirably purified by sublimation before proceeding to membrane formation. This is to prevent as much as possible residue from being left in the crucible containing the product during film formation. The purpose of this is to physically remove substances that are easily decomposed by heating.
In the case of sublimation, it is common to apply a heating temperature gradient in order to produce a purification effect. Also, since it does not sublime at atmospheric pressure, it is necessary to reduce the pressure with a vacuum pump. The condition of sublimation purification is usually determined visually because the required time differs depending on the sublimation target.

A 1,10-phenanthroline compound to be evaluated is formed into a film using a vacuum deposition machine to prepare an element for evaluation.
A device for evaluation is prepared by using a metal mask on a substrate made of quartz glass or the like to which a pretreated electrode is attached and having a square shape of about 2 mm square. As for the element, one or a plurality of elements are fabricated on quartz glass. Normally, it is desirable to produce a plurality of them.

Pretreatment is generally performed in the following manner. As for the pretreatment, the condition of the treatment affects accurate evaluation, so it is necessary to carry out the pretreatment carefully and carefully.
Using a diamond cutter or the like, the substrate with the anode electrode is cut into a size suitable for the cell for evaluation. Since fine dust and the like remain on the substrate when the metal of the electrode is adhered, it is washed and removed. In particular, metals often have rough surfaces because they are adhered to substrates by sputtering or the like. If the device is used as it is, the device may be short-circuited or non-light-emitting portions may occur because the deposited films cannot be laminated evenly. This greatly contributes to evaluation of device lifetime and the like.
Therefore, first, in order to smooth the surface of the metal electrode and degrease the entire substrate, apply acetone (for electronic materials) to a non-woven wiper (for example, Bemcot (Bemcot is a registered trademark of Asahi Kasei Co., Ltd. (Registered No. 1153841 and 6 others))). and lightly polish the surface of the cut substrate. Then, it is immersed in an ultrasonic cleaner containing an aqueous solution of a detergent (for example, Semico Clean (Semico Clean is registered trademark of Furuuchi Chemical Co., Ltd. (Registered Trademark No. 6017459)) diluted with water and subjected to ultrasonic cleaning for about 10 minutes. etc. can be removed from the substrate.
In order to remove the detergent adhering to the substrate, the substrate is immersed in an ultrasonic cleaner filled with distilled water and subjected to ultrasonic cleaning for about 10 minutes.
In addition, if moisture remains on the substrate, it affects the film formation and also affects the lifetime. Ultrasonic cleaning is performed by immersing it to a certain extent. Finally, it is immersed in a boiling solution of isopropyl alcohol (same) for 5 minutes, washed with ultraviolet rays and ozone, and dried in a desiccator under reduced pressure.
These series of operations are performed in a fume hood due to the problem of flammability of acetone and isopropyl alcohol.

Hereinafter, the constituent elements of the organic EL device of the present invention will be described by taking as an example an element configuration consisting of anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/cathode. The organic EL device of the present invention is preferably supported by a substrate. The material of the substrate is not particularly limited, and examples thereof include those commonly used in conventional organic EL devices, such as glass, quartz glass, and transparent plastic.

As the anode of the organic EL element of the present invention, an electrode material can be a single metal having a large work function (4 eV or more), an alloy of metals having a large work function (4 eV or more), a conductive substance, or a mixture thereof. preferable. Specific examples thereof include metals such as gold, silver and copper, conductive transparent materials such as ITO (indium-tin oxide), tin oxide (SnO ₂ ) and zinc oxide (ZnO), and highly conductive materials such as polypyrrole and polythiophene. Molecular materials are included.
Using these electrode materials, the anode can be formed by a method such as vapor deposition, sputtering, or coating. The sheet electric resistance of the anode is preferably several hundred Ω/cm ² or less. Although the film thickness of the anode depends on the material, it is generally about 5 to 1,000 nm, preferably 10 to 500 nm.

As the cathode, it is preferable to use a simple metal with a small work function (4 eV or less), an alloy of metals with a small work function (4 eV or less), a conductive substance, or a mixture thereof as an electrode material. Specific examples thereof include lithium, lithium-indium alloy, sodium, sodium-potassium alloy, magnesium, magnesium-silver alloy, magnesium-indium alloy, aluminum, aluminum-lithium alloy, aluminum-magnesium alloy and the like.
A cathode can be produced using these electrode materials by a method such as vapor deposition or sputtering.
The sheet electric resistance of the cathode is preferably several hundred Ω/cm ² or less. Although the film thickness of the cathode depends on the material, it is generally about 5 to 1,000 nm, preferably 10 to 500 nm. At least one of the anode and the cathode is preferably transparent or translucent in order to efficiently extract light emitted from the organic EL device of the present invention.

The washed electrode substrate is set in a vapor deposition machine or a spin coater in order to form the hole injection layer of the anode with as little exposure to the atmosphere as possible. Low-molecular-weight compounds that can be vapor-deposited are prepared using a vacuum vapor deposition machine, and compounds that have a large molecular weight and are not suitable for vapor deposition are prepared by dissolving them in an appropriate solvent and applying them.

A hole injection layer is laminated on the anode electrode.
The hole injection layer is a layer inserted to improve the injection properties of holes injected into the organic thin film from the anode. The metal used for the anode has a large work function, generally about -5 eV. Therefore, an organic compound having a highest occupied molecular orbital (HOMO) close to this work function does not require a hole injection layer. The barrier occurs because there is some difference between the occupied orbitals (HOMO). Due to this, the holes generated in the anode cannot efficiently move to the organic thin film. Therefore, this layer is provided to solve this problem.
It is usually laminated with a thickness of 10 to 200 nm.

As a compound that can be used in the hole injection layer, copper phthalocyanine (CuPc) represented by the following formula can be exemplified as a low-molecular-weight compound that can be vapor-deposited.

DNTPD described in Japanese Patent Application Laid-Open No. 9-301934 of the present applicant can also be exemplified as a compound that can be vapor-deposited as a hole injection layer.

Examples of the hole injection layer that can be applied include PDOT-PSS (polymer mixture) represented by the following chemical formula, which is a water-soluble polymer.

Similarly, PTPD-1 and PPBI represented by the following chemical formulas can be used.

Similarly, PES-1 and PES-2 described in Japanese Patent Application Laid-Open No. 9-188756 of the present applicant can also be used as a hole injection layer by adding an antimony complex called TBPAH exemplified below. .

A hole transport layer is laminated over the hole injection layer.
The hole transport layer is made of a hole transport compound and has the function of transporting holes injected from the anode to the light emitting layer. Preferably, the hole transport material has a hole mobility of at least 10 ⁻⁶ cm ² /Vsec or greater when the hole transport compound is placed between two electrodes in an electric field and holes are injected from the anode. . Such a hole-transporting substance may be selected from materials conventionally used as charge injection materials for holes in photoconductive materials and known materials used in hole-transporting layers of organic EL devices. can be selected and used.

Examples of hole transfer substances include N,N'-di(1-naphthyl)-N,N'-diphenyl-4,4-diaminophenyl (α-NPD).

BABP listed in JP-A-2004-115441 of the present applicant, DTASi listed in JP-A-2005-220088, DNDPN listed in JP-A-2008-201676, CzTDA and DBTDTA listed in JP-A-2010-254635 etc. can be exemplified.

Further, 4DBFHPB and 4DBTHPB described in JP-A-2019-26556 can be exemplified.

These compounds can be used alone, or can be used by stacking them as a plurality of layers, and can also be used by co-evaporating and mixing a plurality of compounds.

For the light-emitting layer of the organic EL element of the present invention, any light-emitting material generally used by those skilled in the art can be used without particular problems. As for light-emitting materials, phosphorescent materials with high quantum efficiency and thermally activated delayed fluorescent materials are recently used. The novel 1,10-phenanthroline compounds of this invention have energy levels that cause them to emit light appropriately.

The light-emitting layer is formed from a host material and a light-emitting material (dopant) [Appl. Phys. Lett. , 65 3610 (1989)]. The luminescent material is used in combination with a host material to avoid concentration quenching and to efficiently transfer the luminescent energy to the luminescent material. In general, the luminescent material is preferably 0.01-40% by weight, more preferably 0.1-20% by weight, relative to the host material.

Examples of the blue phosphorescent material include FIrpic, FIr6, FIrN4, and Ir(Fppy)3 as exemplified in JP-A-2010-251565.

Green phosphorescent materials are described in Journal of the American Chemical Society (2001), 123(18), 4304-4312. Examples include Ir(ppy) ₂ acac described and Ir(ppy) ₃ described in Pure and Applied Chemistry 71(11) 2095-2106 (1999).

で示されるリン光材料や、特開２００９－１４９６０７号公報記載の下記式 As a red phosphorescent material, the following formula described in JP-A-2009-132688

And the phosphorescent material represented by, the following formula described in JP 2009-149607

で示されるリン光材料、また特開２００９－１６４６１４号公報記載の下記式

Phosphorescent material represented by, also the following formula described in JP 2009-164614

で示されるリン光材料、あるいは特開２０１３－１５５１５３号公報記載の下記式

The phosphorescent material represented by, or the following formula described in JP 2013-155153

などのリン光材料を例示することができる。（Ｂｕは、ブチル基を意味する。）

can be exemplified by phosphorescent materials such as (Bu means a butyl group.)

Materials that emit deep red light include (DPQ) ₂ Ir (dpm) represented by the following formula described in Chemistry-a European Journal 25 (30) 7308-7314 published in 2019.

等のイリジウム錯体を例示することができる。非常に深い最低空軌道準位（ＬＵＭＯ）（‐３．８ｅＶ）を持つ本化合物に対しては、ホスト材料も同様に深い最低空軌道準位（ＬＵＭＯ）が要求される。
また熱活性化遅延蛍光については、１９３０年代よりエオシンＹ等で現象が現れることを確認されていた。本格的にこの分野で利用を試みたのは、２０１０年の九州大学の安達教授らのグループである。

iridium complexes such as For this compound having a very deep lowest unoccupied molecular orbital level (LUMO) (-3.8 eV), the host material is also required to have a deep lowest unoccupied molecular orbital level (LUMO).
As for thermally activated delayed fluorescence, it has been confirmed since the 1930s that the phenomenon appears in eosin Y and the like. In 2010, a group led by Professor Adachi of Kyushu University made a full-fledged attempt to use it in this field.

As the blue material of the thermally activated delayed fluorescence material, ν-DABNA described in Nature Photonics 13, 678-692, (2019),

Adv. DABNA-1 and DABNA-2 described in Mater 2016, 28 (14), 2777-2781,

などを例示することができる。 2CzPN described in Nature 492, 234-238, (2012)

etc. can be exemplified.

For the green heat-activated delayed fluorescent substance, 4CzIPN described in Nature 492, 234-238, (2012),

などを例示することができる。 Chemical Communications (Cambridge, United Kingdom) (2012), 48, (93), 11392-11394. PXZ-TRZ described

etc. can be exemplified.

For the red heat-activated delayed fluorescer, HAP-3TPA as described in U.S. Patent Application Publication No. 2019/0074449;

を例示することができる。 Mater. Horiz. , 2016, 3, 5TCzBN described in 145-151

can be exemplified.

In addition, the novel 1,10-phenanthroline compound of the present invention is applicable to a novel organic EL light emitting technology called hyperfluorescence proposed by Professor Adachi of Kyushu University.
Hyperfluorescence technology utilizes the advantages of fluorescent materials that use singlet excitons and thermally activated delayed fluorescent materials that use triplet excitons to achieve high efficiency and long life of organic EL devices. This technology is attracting attention both in Japan and overseas.

Currently, organic EL devices generally use materials such as phosphorescent materials for red and green, and fluorescent materials for blue. As for phosphorescent materials, there are no materials that are suitable for practical use in blue, and although they have superior luminous efficiency to fluorescent materials, they are in a severe situation in terms of color purity and cost due to the use of rare metals such as iridium metal.
Therefore, thermally activated delayed fluorescence materials that do not contain rare metals and can use triplet excitons like phosphorescent materials can fully compensate for the drawbacks of phosphorescent materials, particularly in terms of cost.

の三重項励起子のエネルギーギャップは２．８８ｅＶであるが、本発明の新規な１，１０－フェナントロリン化合物の三重項励起子のエネルギーギャップは３．０～３．１ｅＶと大きいため十分な電荷の閉じ込め効果を有する。また一緒に使用されている[化３１]記載のν‐ＤＡＢＮＡのエネルギーギャップも２．１ｅＶでありこちらの電荷の閉じ込めを行うことができる。
一般に赤色や緑色の発光材料は、青色発光材料のエネルギーギャップほど大きくないためいずれの色の発光材料の電荷の閉じ込めも十分に行うことが可能である。 For example, the following compound (HDT-1) of a blue delayed activation fluorescent material described in Nature Photonics (doi.org/10.1038/s41566-020-00745-z) by Adachi et al.

is 2.88 eV, but the triplet exciton energy gap of the novel 1,10-phenanthroline compound of the present invention is as large as 3.0 to 3.1 eV. Has a confinement effect. Also, the energy gap of ν-DABNA described in [Chemical 31] used together is 2.1 eV, and this charge can be confined.
In general, the energy gaps of red and green light emitting materials are not as large as those of blue light emitting materials, so that the charge can be sufficiently confined in any color light emitting material.

を例示することができる。 For the host material used together with these light-emitting materials, the following compounds described in Japanese Patent No. 5683784

can be exemplified.

を例示することができる。 In addition, the following compounds described in the applicant's patent No. 5325402

can be exemplified.

も例示することができる。 The following compounds described in JP-A-2010-13421 of the present applicant

can also be exemplified.

The following compound described in the applicant's patent No. 5674266

を例示することができる。 Furthermore, the following compounds described in the applicant's patent No. 5727237

can be exemplified.

A hole-blocking layer can also be inserted between the light-emitting layer and the electron-transporting layer. A hole block is a layer that literally prevents holes that have not been recombined with electrons at the time of light emission from leaking into the electron transport layer. Hole leakage often occurs when the charge is out of balance affecting hole mobility and electron mobility. When the leaked holes recombine at the interface between the electron-transporting layer or the light-emitting layer and the electron-transporting layer, light is emitted from the recombination site, and light with a wavelength different from that obtained from the light-emitting layer is emitted. .

Materials used as hole-blocking materials are characterized by having a large value of the highest occupied molecular orbital (HOMO). Since holes are injected from the anode, if a material with a highest occupied molecular orbital (HOMO) value close to the work function of the anode electrode is used, the holes can easily move, causing a hole penetration phenomenon. .

ＤＢＴ‐ＴＲＺ

を挙げることができる。 As the hole-blocking material, any material having a large highest occupied molecular orbital (HOMO) value can be used as described above. or,

DBT-TRZ

can be mentioned.

The value of the highest occupied molecular orbital (HOMO) of DBF-TRZ is -6.4 eV, and the value of the highest occupied molecular orbital (HOMO) of DBT-TRZ is -6.3 eV. to large.

The hole blocking layer is followed by the electron transport layer. As for the electron transport material used here, the electron transport material described in general formula [1] or general formula [2] is used.

In the electron-transporting material represented by the general formula [1], the two 4-isoquinoline compounds bonded to the 1,10-phenanthroline compound may be the same or different, but are preferably the same. The following compounds can be exemplified.

In the electron-transporting material represented by the general formula [2], the two 6-quinoline compounds bonded to the 1,10-phenanthroline compound may be the same or different, but are preferably the same. The following compounds can be exemplified.

These compounds can be formed into thin films by themselves to form an electron-transporting layer, but two or more compounds can be mixed into a single layer by co-evaporation, or two or more electron-transporting layers can be formed singly. can also be formed.

あるいは、 Further, these compounds are the following compounds described in Japanese Patent No. 5650114

or,

などと混合して用いることもできる。 J. Org. Chem. , 1996, 61 (9), the following compounds described in 3017-3022

It can also be used by mixing with such as.

When used in combination with the above compounds, the total amount of general formula [1] and general formula [2] is 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more of the mixture. It can be used as a ratio.

The method for forming the hole injection layer and the hole transport layer of the device containing the novel 1,10-phenanthroline compound of the present invention is not particularly limited. For example, a dry film-forming method (eg, vacuum deposition method, ionization deposition method, etc.) or a wet film-forming method [solvent coating method (eg, spin coating method, casting method, inkjet method, etc.)] can be used. When the electron-transporting layer is formed by a wet film-forming method, the lower layer may be eluted, so dry film-forming methods (eg, vacuum vapor deposition method, ionization vapor deposition method, etc.) are limited. For fabrication of the element, the above film-forming methods may be used together.
When forming each layer such as a hole transport layer, a light emitting layer, an electron transport layer, etc. by a vacuum deposition method, vacuum deposition conditions are not particularly limited. Usually, under a vacuum of about 10 ^-5 Torr or less, at a boat temperature (vapor deposition source temperature) of about 50 to 500°C and a substrate temperature of about -50 to 300°C, the deposition rate is 0.01 to 50 nm/sec. It is preferable to vapor-deposit to some extent. When forming each layer of a hole transport layer, a light-emitting layer, and an electron transport layer using a plurality of compounds, it is preferable to perform co-evaporation while controlling the temperature of each boat containing the compounds.

When the hole injection layer and the hole transport layer are formed by a solvent coating method, the components constituting each layer are dissolved or dispersed in a solvent to prepare a coating liquid. Examples of solvents include hydrocarbon solvents (e.g. heptane, toluene, xylene, cyclohexane, etc.), ketone solvents (e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), halogen solvents (e.g., dichloromethane, chloroform, chlorobenzene, dichlorobenzene, etc.). , ester solvents (eg, ethyl acetate, butyl acetate, etc.), alcohol solvents (eg, methanol, ethanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ether solvents (eg, dibutyl ether, tetrahydrofuran, 1,4-dioxane, 1 , 2-dimethoxyethane, etc.), aprotic solvents (eg, N,N'-dimethylacetamide, dimethylsulfoxide, etc.), water and the like. A single solvent may be used, or a plurality of solvents may be used in combination.

The film thickness of each layer such as the hole transport layer, the light emitting layer, the electron transport layer, etc. is not particularly limited, but is usually 5 to 5,000 nm.
The organic EL element of the present invention can be protected by providing a protective layer (sealing layer) or encapsulating the element in an inert substance for the purpose of blocking contact with oxygen, moisture, and the like. Examples of inert substances include paraffin, silicon oil, fluorocarbons, and the like. Materials used for the protective layer include fluororesins, epoxy resins, silicone resins, polyesters, polycarbonates, photocurable resins, and the like.

The organic EL device of the present invention can be used as a DC-driven device. When a DC voltage is applied, luminescence is observed by applying a voltage of about 1.5 to 20 V with positive polarity to the anode and negative polarity to the cathode. The organic EL device of the present invention can also be used as an AC-driven device. When an AC voltage is applied, light is emitted when the anode is positive and the cathode is negative. The organic EL device of the present invention can be used for full-color displays such as televisions, mobile phones, and game machines, area color displays such as vehicle warning lights and safety parts, copiers, printers, white backlights for liquid crystal displays, and indoor or outdoor indirect displays. It can be used for various types of lighting such as lighting and desk lighting.

FIG. 27 shows a cross-sectional view of a preferred example of the organic EL device of the present invention.
FIG. 27 shows an example in which an anode 2, a hole injection layer 7, a hole transport layer 5, a light emitting layer 3, a hole blocking layer 9, an electron transport layer 6, an electron injection layer 8 and a cathode 4 are sequentially provided on a substrate 1. is. In this case, by providing the hole injection layer 7, the adhesiveness between the anode 2 and the hole transport layer 5 is improved, the injection of holes from the anode is improved, and the voltage of the light emitting device is reduced. . Also, this example is an example in which a hole blocking layer 9 is inserted. This separates the functions of charge transport and light emission, and increases the degree of freedom in material selection, resulting in higher efficiency of light emission and greater freedom in the color of emitted light. A hole-blocking layer 9 can be inserted between the light-emitting layer 3 and the electron-transporting layer 6 .

Synthesis example

The present invention will be described in more detail below with reference to Synthesis Examples and Examples, but the present invention is not limited thereto.

窒素導入管、還流冷却管、温度計およびメカニカルスターラーのついた３００ｍｌの４つ口丸底フラスコに、炭酸ナトリウム４．７ｇ（１７．８ｍｍｏｌ×２．５当量）と水５５ｍｌを加え撹拌する。続いてテトラヒドロフラン１１０ｍｌ、４－イソキノリンボロン酸エステル１０．０ｇ（１７．８ｍｍｏｌ×２．２当量）と２，９－ジクロロ‐４，７‐ジフェニルフェナントロリン７．１ｇ（１７．８ｍｍｏｌ）を加え窒素置換を１５分実施する。その後テトラキストリフェニルホスフィン０．１ｇ（１７．８ｍｍｏｌ×０．５％）を加え湯浴で６５～６７℃で１２時間撹拌する。反応が進むにつれ目的物の結晶が析出する。
所定の時間が経過した後室温まで冷却し、析出した結晶を吸引ろ過にて回収した。
得られた結晶は、オルソジクロロベンゼン２００ｍｌと活性白土１ｇ加え再結晶を行った。この操作により目的の化合物番号（Ｉ）の化合物を８．６ｇ回収した。収率は８２．４％であった。
このうち８ｇを昇華精製した。昇華条件は、高温側３１０℃、中温側２９０℃および低温側２３０℃で真空下４．５時間加熱した。室温まで冷却し目的物を５．８ｇ回収した。この操作での回収率は、７２．５％であった。得られた結晶は、素子化に使用した。
昇華精製後の化合物について、元素分析を行い化合物の同定を行った。その結果を表１に示す。高速液体クロマトグラフでの純度確認は、９９．７８％であった。 Synthesis Example 1: Synthesis of Compound No. (I)

4.7 g (17.8 mmol×2.5 equivalents) of sodium carbonate and 55 ml of water are added to a 300 ml four-necked round bottom flask equipped with a nitrogen inlet tube, a reflux condenser, a thermometer and a mechanical stirrer, and stirred. Subsequently, 110 ml of tetrahydrofuran, 10.0 g (17.8 mmol×2.2 equivalents) of 4-isoquinoline boronic acid ester and 7.1 g (17.8 mmol) of 2,9-dichloro-4,7-diphenylphenanthroline were added and nitrogen substitution was carried out. Run for 15 minutes. After that, 0.1 g (17.8 mmol×0.5%) of tetrakistriphenylphosphine is added and stirred at 65-67° C. for 12 hours in a hot water bath. As the reaction progresses, crystals of the desired product are deposited.
After a predetermined time had elapsed, the mixture was cooled to room temperature, and the precipitated crystals were collected by suction filtration.
The obtained crystals were recrystallized by adding 200 ml of orthodichlorobenzene and 1 g of activated clay. By this operation, 8.6 g of the target compound number (I) was recovered. Yield was 82.4%.
8 g of this was purified by sublimation. The sublimation conditions were 310° C. on the high temperature side, 290° C. on the medium temperature side, and 230° C. on the low temperature side under vacuum for 4.5 hours. After cooling to room temperature, 5.8 g of the desired product was recovered. The recovery for this operation was 72.5%. The obtained crystal was used for device fabrication.
The compound after sublimation purification was subjected to elemental analysis to identify the compound. Table 1 shows the results. Purity confirmation by high performance liquid chromatography was 99.78%.

窒素導入管、還流冷却管、温度計およびメカニカルスターラーのついた３００ｍｌの４つ口丸底フラスコに、炭酸ナトリウム４．７ｇ（１７．８ｍｍｏｌ×２．５当量）と水５５ｍｌを加え撹拌する。続いてテトラヒドロフラン１１０ｍｌ、６‐メチル‐４‐イソキノリンボロン酸エステル１０．５ｇ（６‐メチル‐４‐ブロモイソキノリンより調製したもの）（１７．８ｍｍｏｌ×２．２当量）と２，９－ジクロロ‐４，７‐ジフェニルフェナントロリン７．１ｇ（１７．８ｍｍｏｌ）を加え窒素置換を１５分実施する。その後テトラキストリフェニルホスフィン０．１ｇ（１７．８ｍｍｏｌ×０．５％）を加え湯浴で６５～６７℃で１２時間撹拌する。反応が進むにつれ目的物の結晶が析出する。
所定の時間が経過した後室温まで冷却し、析出した結晶を吸引ろ過にて回収した。
得られた結晶は、オルソジクロロベンゼン２００ｍｌと活性白土１ｇ加え再結晶を行った。この操作により目的の化合物番号（II）－２の化合物を８．８ｇ回収した。収率は８０．４％であった。
このうち８ｇを昇華精製した。昇華条件は、高温側３１０℃、中温側２９０℃および低温側２３０℃で真空下４．５時間加熱した。室温まで冷却し目的物を５．４ｇ回収した。この操作での回収率は、６７．５％であった。 Synthesis Example 2: Synthesis of Compound No. (II)-2

4.7 g (17.8 mmol×2.5 equivalents) of sodium carbonate and 55 ml of water are added to a 300 ml four-necked round bottom flask equipped with a nitrogen inlet tube, a reflux condenser, a thermometer and a mechanical stirrer, and stirred. followed by 110 ml of tetrahydrofuran, 10.5 g of 6-methyl-4-isoquinoline boronic ester (prepared from 6-methyl-4-bromoisoquinoline) (17.8 mmol×2.2 equivalents) and 2,9-dichloro-4 ,7-diphenylphenanthroline 7.1 g (17.8 mmol) is added, and nitrogen substitution is performed for 15 minutes. After that, 0.1 g (17.8 mmol×0.5%) of tetrakistriphenylphosphine is added and stirred at 65-67° C. for 12 hours in a hot water bath. As the reaction progresses, crystals of the desired product are deposited.
After a predetermined time had elapsed, the mixture was cooled to room temperature, and the precipitated crystals were collected by suction filtration.
The obtained crystals were recrystallized by adding 200 ml of orthodichlorobenzene and 1 g of activated clay. By this operation, 8.8 g of the target compound No. (II)-2 was recovered. Yield was 80.4%.
8 g of this was purified by sublimation. The sublimation conditions were 310° C. on the high temperature side, 290° C. on the medium temperature side, and 230° C. on the low temperature side under vacuum for 4.5 hours. After cooling to room temperature, 5.4 g of the desired product was recovered. The recovery for this operation was 67.5%.

合成例２に従い、１‐メチル‐４‐イソキノリンボロン酸エステル１０．５ｇ（１‐メチル‐４‐ブロモイソキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 3: Synthesis of Compound No. (II)-5

The desired product was obtained in the same manner as in Synthesis Example 2, except that 10.5 g of 1-methyl-4-isoquinoline boronic acid ester (prepared from 1-methyl-4-bromoisoquinoline) was used.

合成例２に従い、１‐エチル‐４‐イソキノリンボロン酸エステル１１．１ｇ（１‐エチル‐４‐ブロモイソキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 4: Synthesis of Compound No. (III)-5

The desired product was obtained in the same manner as in Synthesis Example 2, except that 1-ethyl-4-isoquinoline boronic acid ester (prepared from 1-ethyl-4-bromoisoquinoline) was changed to 11.1 g.

合成例２に従い、１‐ノルマルプロピル‐４‐イソキノリンボロン酸エステル１１．６ｇ（１‐ノルマルプロピル‐４‐ブロモイソキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 5: Synthesis of Compound No. (IV)-5

The desired product was obtained in the same manner as in Synthesis Example 2, except that 1-n-propyl-4-isoquinoline boronate ester (11.6 g, prepared from 1-n-propyl-4-bromoisoquinoline) was used.

窒素導入管、還流冷却管、温度計およびメカニカルスターラーのついた３００ｍｌの４つ口丸底フラスコに、炭酸ナトリウム４．７ｇ（１７．８ｍｍｏｌ×２．５当量）と水５５ｍｌを加え撹拌する。続いてテトラヒドロフラン１１０ｍｌ、４－イソキノリンボロン酸エステル１０．０ｇ（１７．８ｍｍｏｌ×２．２当量）と２，９－ジクロロ‐４，７‐ジフェニルフェナントロリン７．１ｇ（１７．８ｍｍｏｌ）を加え窒素置換を１５分実施する。その後テトラキストリフェニルホスフィン０．１ｇ（１７．８ｍｍｏｌ×０．５％）を加え湯浴で６５～６７℃で１８時間撹拌する。反応が進むにつれ目的物の結晶が析出する。
所定の時間が経過した後室温まで冷却し、析出した結晶を吸引ろ過にて回収した。
得られた結晶は、オルソジクロロベンゼン２００ｍｌと活性白土１ｇ加え再結晶を行った。この操作により目的の化合物番号（VI）の化合物を８．４ｇ回収した。収率は８０．４％であった。
このうち７．３ｇを昇華精製した。昇華条件は、高温側３３０℃、中温側３１０℃および低温側２５０℃で真空下３時間加熱した。室温まで冷却し目的物を６．２ｇ回収した。この操作での回収率は、８４．９％であった。得られた結晶は、素子化に使用した。
昇華精製後の化合物について、元素分析を行い化合物の同定を行った。その結果を表２に示す。高速液体クロマトグラフでの純度確認は、９９．６３％であった。 Synthesis Example 6: Synthesis of Compound No. (VI)

4.7 g (17.8 mmol×2.5 equivalents) of sodium carbonate and 55 ml of water are added to a 300 ml four-necked round bottom flask equipped with a nitrogen inlet tube, a reflux condenser, a thermometer and a mechanical stirrer, and stirred. Subsequently, 110 ml of tetrahydrofuran, 10.0 g (17.8 mmol×2.2 equivalents) of 4-isoquinoline boronic acid ester and 7.1 g (17.8 mmol) of 2,9-dichloro-4,7-diphenylphenanthroline were added and nitrogen substitution was carried out. Run for 15 minutes. After that, 0.1 g (17.8 mmol×0.5%) of tetrakistriphenylphosphine is added and stirred at 65 to 67° C. for 18 hours in a hot water bath. As the reaction progresses, crystals of the desired product are deposited.
After a predetermined time had elapsed, the mixture was cooled to room temperature, and the precipitated crystals were collected by suction filtration.
The obtained crystals were recrystallized by adding 200 ml of orthodichlorobenzene and 1 g of activated clay. By this operation, 8.4 g of the target compound number (VI) was recovered. Yield was 80.4%.
7.3 g of this was purified by sublimation. The sublimation conditions were 330° C. on the high temperature side, 310° C. on the medium temperature side, and 250° C. on the low temperature side, and heated under vacuum for 3 hours. After cooling to room temperature, 6.2 g of the desired product was recovered. The recovery for this operation was 84.9%. The obtained crystal was used for device fabrication.
The compound after sublimation purification was subjected to elemental analysis to identify the compound. Table 2 shows the results. Purity confirmation by high performance liquid chromatography was 99.63%.

窒素導入管、還流冷却管、温度計およびメカニカルスターラーのついた３００ｍｌの４つ口丸底フラスコに、炭酸ナトリウム４．７ｇ（１７．８ｍｍｏｌ×２．５当量）と水５５ｍｌを加え撹拌する。続いてテトラヒドロフラン１１０ｍｌ、８‐メチル‐６‐キノリンボロン酸エステル１０．５ｇ（８‐メチル‐６‐ブロモキノリンより調製したもの）（１７．８ｍｍｏｌ×２．２当量）と２，９－ジクロロ‐４，７‐ジフェニルフェナントロリン７．１ｇ（１７．８ｍｍｏｌ）を加え窒素置換を１５分実施する。その後テトラキストリフェニルホスフィン０．１ｇ（１７．８ｍｍｏｌ×０．５％）を加え湯浴で６５～６７℃で１８時間撹拌する。反応が進むにつれ目的物の結晶が析出する。
所定の時間が経過した後室温まで冷却し、析出した結晶を吸引ろ過にて回収した。
得られた結晶は、オルソジクロロベンゼン２００ｍｌと活性白土１ｇ加え再結晶を行った。この操作により目的の化合物番号（ＶＩＩ）－２の化合物を８．３ｇ回収した。収率は７５．９％であった。
このうち７．５ｇを昇華精製した。昇華条件は、高温側３３０℃、中温側３１０℃および低温側２５０℃で真空下３時間加熱した。室温まで冷却し目的物を６．７ｇ回収した。この操作での回収率は、８９．３％であった。 Synthesis Example 7: Synthesis of Compound No. (VII)-2

4.7 g (17.8 mmol×2.5 equivalents) of sodium carbonate and 55 ml of water are added to a 300 ml four-necked round bottom flask equipped with a nitrogen inlet tube, a reflux condenser, a thermometer and a mechanical stirrer, and stirred. This was followed by 110 ml of tetrahydrofuran, 10.5 g of 8-methyl-6-quinoline boronic ester (prepared from 8-methyl-6-bromoquinoline) (17.8 mmol×2.2 equivalents) and 2,9-dichloro-4. ,7-diphenylphenanthroline 7.1 g (17.8 mmol) is added, and nitrogen substitution is performed for 15 minutes. After that, 0.1 g (17.8 mmol×0.5%) of tetrakistriphenylphosphine is added and stirred at 65 to 67° C. for 18 hours in a hot water bath. As the reaction progresses, crystals of the desired product are deposited.
After a predetermined time had elapsed, the mixture was cooled to room temperature, and the precipitated crystals were collected by suction filtration.
The obtained crystals were recrystallized by adding 200 ml of orthodichlorobenzene and 1 g of activated clay. By this operation, 8.3 g of the target compound number (VII)-2 was recovered. Yield was 75.9%.
7.5 g of this was purified by sublimation. The sublimation conditions were 330° C. on the high temperature side, 310° C. on the medium temperature side, and 250° C. on the low temperature side, and heated under vacuum for 3 hours. After cooling to room temperature, 6.7 g of the desired product was recovered. The recovery for this operation was 89.3%.

合成例７に従い、２‐メチル‐６‐キノリンボロン酸エステル１０．５ｇ（２‐メチル‐６‐ブロモキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 8: Synthesis of Compound No. (VII)-6

The desired product was obtained in the same manner as in Synthesis Example 7, except that 10.5 g of 2-methyl-6-quinoline boronic acid ester (prepared from 2-methyl-6-bromoquinoline) was used.

合成例７に従い、２‐エチル‐６‐キノリンボロン酸エステル１１．１ｇ（２‐エチル‐６‐ブロモキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 9: Synthesis of Compound No. (VIII)-6

The desired product was obtained in the same manner as in Synthesis Example 7, except that 11.1 g of 2-ethyl-6-quinoline boronic acid ester (prepared from 2-ethyl-6-bromoquinoline) was used.

合成例７に従い、２‐ｎ－プロピル‐６‐キノリンボロン酸エステル１１．６ｇ（２‐ｎ‐プロピル‐６‐ブロモキノリンより調製したもの）に変えた以外は同様の操作で目的物を得た。 Synthesis Example 10: Synthesis of Compound No. (IX)-6

The desired product was obtained in the same manner as in Synthesis Example 7, except that 11.6 g of 2-n-propyl-6-quinoline boronic acid ester (prepared from 2-n-propyl-6-bromoquinoline) was used. .

窒素導入管、還流冷却管、温度計およびメカニカルスターラーのついた３００ｍｌの４つ口丸底フラスコに、炭酸ナトリウム４．７ｇ（１７．８ｍｍｏｌ×２．５当量）と水５５ｍｌを加え撹拌する。続いてテトラヒドロフラン１１０ｍｌ、３‐キノリンボロン酸エステル１０．０ｇ（１７．８ｍｍｏｌ×２．２当量）と２，９－ジクロロ‐４，７‐ジフェニルフェナントロリン７．１ｇ（１７．８ｍｍｏｌ）を加え窒素置換を１５分実施する。その後テトラキストリフェニルホスフィン０．１ｇ（１７．８ｍｍｏｌ×０．５％）を加え湯浴で６５～６７℃で１８時間撹拌する。反応が進むにつれ目的物の結晶が析出する。
所定の時間が経過した後室温まで冷却し、析出した結晶を吸引ろ過にて回収した。
得られた結晶は、オルソジクロロベンゼン２００ｍｌと活性白土１ｇ加え再結晶を行った。この操作により目的の化合物を９．０ｇ回収した。収率は８６．２％であった。
このうち５．５ｇを昇華精製した。昇華条件は、高温側３５０℃、中温側３３０℃および低温側２７０℃で真空下２時間加熱した。室温まで冷却し目的物を４．２４ｇ回収した。この操作での回収率は、７７．１％であった。
昇華精製後の化合物について、元素分析を行い化合物の同定を行った。その結果を表３に示す。高速液体クロマトグラフでの純度確認は、９９．８８％であった。 Comparative Example: Synthesis of 2,9-di(quinolin-3-yl)-4,7-diphenyl-1,10-phenanthroline

4.7 g (17.8 mmol×2.5 equivalents) of sodium carbonate and 55 ml of water are added to a 300 ml four-necked round bottom flask equipped with a nitrogen inlet tube, a reflux condenser, a thermometer and a mechanical stirrer, and stirred. Subsequently, 110 ml of tetrahydrofuran, 10.0 g (17.8 mmol×2.2 equivalents) of 3-quinoline boronic acid ester and 7.1 g (17.8 mmol) of 2,9-dichloro-4,7-diphenylphenanthroline were added and nitrogen substitution was carried out. Run for 15 minutes. After that, 0.1 g (17.8 mmol×0.5%) of tetrakistriphenylphosphine is added and stirred at 65 to 67° C. for 18 hours in a hot water bath. As the reaction progresses, crystals of the desired product are deposited.
After a predetermined time had elapsed, the mixture was cooled to room temperature, and the precipitated crystals were collected by suction filtration.
The obtained crystals were recrystallized by adding 200 ml of orthodichlorobenzene and 1 g of activated clay. 9.0 g of the target compound was recovered by this operation. Yield was 86.2%.
5.5 g of this was purified by sublimation. The sublimation conditions were 350° C. on the high temperature side, 330° C. on the medium temperature side, and 270° C. on the low temperature side, and heated under vacuum for 2 hours. After cooling to room temperature, 4.24 g of the desired product was recovered. The recovery for this operation was 77.1%.
The compound after sublimation purification was subjected to elemental analysis to identify the compound. Table 3 shows the results. Purity confirmation by high performance liquid chromatography was 99.88%.

Example 1
The compound of compound number (I) in Synthesis Example 1 (hereinafter referred to as 4iq-Bphen), the compound of compound number (VI) in Synthesis Example 6 (hereinafter referred to as 6q-Bphen), and the 2,9-di A device was fabricated using (quinolin-3-yl)-4,7-diphenyl-1,10-phenanthroline (hereinafter referred to as 3q-Bphen) and NBphen described in [0098].
An example of the fabricated device is shown in FIG.
Energy diagrams on the respective elements of 4iq-Bphen, 6q-Bphen and 3q-Bphen are shown in FIG.
FIG. 3 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and NBphen added to 3q-Bphen.
The current density-voltage characteristics are shown in Fig. 4.
The luminance-voltage characteristics are shown in Fig. 5.
Fig. 6 shows the power efficiency-luminance characteristics.
Figure 7 shows the external quantum efficiency vs. luminance characteristics.
FIG. 8 shows the drive life (half life) measurement.
Further, the results of driving life measurement (calculated at a constant initial luminance of 1000 cd/m) are shown in Table 4 (with 20 wt % Liq added) and Table 5 (without Liq added). Here, since Liq (8-hydroxyquinolinolate-lithium) shown in FIG. 1 can be added to the material used for the electron transport layer of the organic EL element to extend the life, the durability of the organic EL element is improved. It is widely used to improve sexuality. As shown in Tables 4 and 5, 4iq-Bphen and 6q-Bphen had long lifetimes in the organic EL devices to which Liq was not added, so FIGS.

As a result of evaluating each characteristic, the comparison compounds 3q-Bphen and NBphen have higher charge injection properties than the 4iq-Bphen and 6q-Bphen of the present invention, as shown in the results of FIGS. 4 and 5 . However, it was found from FIGS. 6 and 7 that the power efficiency and the external quantum efficiency significantly decreased as the luminance increased. It is believed that this is because charge retention occurs in the device using 3q-Bphen and NBphen, and charge recombination in the device is reduced.
On the other hand, 4iq-Bphen and 6q-Bphen of the present invention have little change in power efficiency and external quantum efficiency regardless of the magnitude of luminance. It is considered that this is the result of the fact that charge retention is less likely to occur in the device fabricated using these materials, and that charge injection, transfer, and recombination are balanced in a substantially stable state.
Furthermore, in organic EL devices, it is believed that the addition of Liq suppresses the recrystallization of the electron-transporting layer, making it possible to extend the life of the device. The organic EL device to which no was added exhibited a driving life exceeding 10,000 hours. From the results here, 4iq-Bphen and 6q-Bphen are difficult to recrystallize even without the addition of a lithium complex such as Liq, and can achieve a practically sufficient driving life, which can contribute to the simplification of organic EL devices. It was shown that it can be realized.

また正孔注入層には正孔注入性を向上させ、ＩＴＯ界面の膜質改善の目的で［化１１］および［化１２］記載のＰＴＰＤ－１:ＰＰＢＩを、正孔輸送層には［化１６］記載のα－ＮＰＤを成膜した。電子注入性向上のためにリチウム錯体（Ｌｉｑ）を使用し、陰極にはＡｌを使用した。 Example 2
Devices were fabricated using 4iq-Bphen, 6q-Bphen and 3q-Bphen as a comparative example. For the light-emitting layer, Ir(pq) ₂ acac that emits orange light around 600 nm represented by [Chem. 67] was used.

For the hole injection layer, PTPD-1:PPBI described in [Chem. 11] and [Chem. ] to form a film of α-NPD described above. A lithium complex (Liq) was used to improve electron injection properties, and Al was used for the cathode.

The fabricated element structure is as follows.
ITO (100 nm) (anode)/PTPD-1:PPBI (20 nm) (hole injection layer)/α-NPD (20 nm) (hole transport layer)/α-NPD: 4iq-Bphen or 6q-Bphen or 3q- Bphen (1:1), 3 wt. % Ir(pq) ₂ acac (40 nm) (light emitting layer)/NBPhen (50 nm) (electron transport layer)/NBPhen: 20 wt. % Liq (20 nm) (electron transport layer)/Liq (1 nm) (electron injection layer)/Al (80 nm) (cathode)
An example of the fabricated device is shown in FIG.
FIG. 10 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and NBphen added to 3q-Bphen.
The current density-voltage characteristics are shown in FIG.
The luminance-voltage characteristics are shown in FIG.
Power efficiency-luminance characteristics are shown in FIG.
External quantum efficiency-luminance characteristics are shown in FIG.
FIG. 15 shows the drive life (half life) measurement.
Table 6 shows a summary of device measurement results.

In the table, Von indicates the voltage at 1 _cdm - ² . V ₁₀₀₀ indicates the voltage at 1000 cdm@ ^-2 . EQE ₁₀₀₀ indicates an external quantum efficiency of 1000 cdm@ ^-2 . PE ₁₀₀₀ exhibits a power efficiency of 1000 cdm@ ^-2 hours. LT ₅₀ indicates the 50% luminance decay time at constant current density (25 mAm ⁻² ). LT ₅₀ (@1000 cdm- ² ) indicates the 50% luminance decay time at 1000 cdm- ² .

Example 3
Devices were fabricated using 4iq-Bphen, 6q-Bphen and 3q-Bphen as a comparative example. For the light-emitting layer, (DPQ) ₂ Ir (dpm), which emits deep red light around 670 nm, represented by [Chemical 30] was used.
As in Example 2, PTPD-1:PPBI described in [Chem. 11] and [Chem. A film of α-NPD described in [Chemical 16] was formed. A lithium complex (Liq) was used to improve electron injection properties, and Al was used for the cathode.

The fabricated element structure is as follows.
ITO (130 nm) (anode) / PTPD-1: PPBI (20 nm) (hole injection layer) / α-NPD (20 nm) (hole transport layer) / α-NPD: 4iq-Bphen or 6q-Bphen or 3q- Bphen (1:1), 1 wt. %(DPQ) _2Ir (dpm) (40 nm) (light emitting layer)/4iq-Bphen or 6q-Bphen or 3q-Bphen (50 nm) (electron transport layer)/4iq-Bphen or 6q-Bphen or 3q-Bphen, 20wt .% Liq (20 nm) (electron transport layer with improved electron injection properties)/Liq (1 nm) (electron injection layer)/Al (80 nm) (cathode)
FIG. 16 shows the energy diagrams on the 4iq-Bphen, 6q-Bphen and 3q-Bphen elements of the fabricated elements.
FIG. 17 shows EL spectra showing emission from devices using 4iq-Bphen, 6q-Bphen, and 3q-Bphen, respectively.
The current density-voltage characteristics are shown in FIG.
The luminance-voltage characteristics are shown in FIG.
External quantum efficiency-luminance characteristics are shown in FIG.
FIG. 21 shows the drive life (half life) measurement.
Table 7 shows a summary of device measurement results.

As can be seen from the results in Table 7, the lifetimes of the elements using 4iq-Bphen and 6q-Bphen of the present application in the element configuration fabricated in Example 3 are 67 times longer and 87 times longer than the element using 3q-Bphen. From this fact, it was found that 4iq-Bphen and 6q-Bphen of the present application are materials that allow deep red materials to emit light very efficiently.

Example 4
A device using 4iq-Bphen and 6q-Bphen was produced.
As a comparative compound here, instead of 3q-Bphen, 4DBT46TRZ represented by [Chemical 68] described in Japanese Patent No. 6580613 jointly filed by Yamagata University and the present applicant was used. NBPhen was used for the electron transport layer and the electron injection layer.

The fabricated element structure is as follows.
ITO (130 nm) (anode) / PTPD-1: PPBI (20 nm) (hole injection layer) / α-NPD (20 nm) (hole transport layer) / α-NPD: 4iq-Bphen or 6q-Bphen or 4DBT46TRZ ( 1:1), 1 wt. % (DPQ) ₂ Ir (dpm) (40 nm) (light-emitting layer)/NBPhen (50 nm) (electron-transporting layer)/NBPhen, 20 wt.% Liq (20 nm) (electron-transporting layer with improved electron injection properties)/Liq (1 nm) (electron injection layer)/Al (80 nm) (cathode)
FIG. 22 shows EL spectra showing light emission from devices using 4iq-Bphen, 6q-Bphen, and 4DBT46TRZ of the fabricated devices.
The current density-voltage characteristics are shown in FIG.
The luminance-voltage characteristics are shown in FIG.
External quantum efficiency-luminance characteristics are shown in FIG.
FIG. 26 shows the drive life (half life) measurement.
Table 8 shows a summary of the device measurement results.

The manufacturing conditions for the device manufactured in Example 4 are suitable for allowing 4DBT46TRZ to function efficiently in the light-emitting layer. As for 6q-Bphen, since the device conditions were not optimized, the lifetime was lower than that of 4DBT46TRZ. 1.6 times longer life was achieved.

1 substrate 2 anode (ITO)
3 light emitting layer 4 cathode 5 hole transport layer 6 electron transport layer 7 hole injection layer 8 electron injection layer 9 hole blocking layer

Claims (8)

the following general formula [1]

[In the formula, R ¹ is hydrogen or a group independently selected from the group consisting of a methyl group, an ethyl group, a normal propyl group and an isopropyl group. ]
An organic electroluminescence device containing 1,10-phenanthroline compounds represented by the following general formula [2]

[In the formula, R ² is hydrogen or a group independently selected from the group consisting of a methyl group, an ethyl group, a normal propyl group and an isopropyl group. ]
An organic electroluminescence device containing 1,10-phenanthroline compounds represented by An organic electroluminescence device using the 1,10-phenanthroline compounds according to claim 1 in an electron-transporting layer and/or a light-emitting layer. 3. An organic electroluminescence device using the 1,10-phenanthroline compounds according to claim 2 in an electron-transporting layer and/or a light-emitting layer. An organic electroluminescence lighting device using the organic electroluminescence device according to claim 3 . An organic electroluminescence lighting device using the organic electroluminescence device according to claim 4 . A deep red organic electroluminescence illumination using the organic electroluminescence device according to claim 3 . A deep red organic electroluminescence illumination using the organic electroluminescence device according to claim 4 .

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