JP2015120779A - Delayed fluorescence light emitting substance, and organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence light emitting substance and a thermally activated delayed fluorescence light emitting substance exhibiting a high internal quantum yield, and to provide an organic EL element exhibiting a high external light emitting efficiency obtained by using the fluorescence light emitting substance and the thermally activated delayed fluorescence light emitting substance for a light emitting layer of the organic EL element.SOLUTION: A delayed fluorescence light emitting substance is aromatic hydrocarbon having a substituent Xn in either one of aromatic ring among a benzene ring, a naphthalene ring, a biphenyl ring and a fluorene ring, and the substituent Xn is selected from either one of residues of benzothiazole, coumarin, fluorenone, acridone, quinacridone, acridine, anthraquinone, thioxanthone, phthalimide, naphthyl dicarboimide and pyrene, or a residue of a derivative of the either one, and the number of the substituent is 1 or more. There is also provided an organic EL element containing the delayed fluorescence light emitting substance in a light emitting layer.

Description

  The present invention relates to a novel fluorescent and thermally activated delayed fluorescent emitter and an organic EL device using the same.

  An organic EL element having a fine laminated structure including a light emitting layer is expected to be applied as an energy-saving next-generation illumination or a next-generation display.

  The light-emitting body provided by the present invention is used together with a host compound or the like as a component of the light-emitting layer constituting the laminated structure of the organic EL element. In addition, by using the light emitter provided by the present invention, an organic EL element having high luminous efficiency can be manufactured.

The light emitters used in the organic EL element are roughly classified into three types: fluorescent light emitters, phosphorescent light emitters, and fluorescent and thermally activated delayed fluorescent light emitters.
In the fluorescent emitter, when the electrons and holes are recombined, singlet excitons which are fluorescent excitons are formed only 25% of all excitons, so that the internal quantum yield is 25% at the maximum. In addition, the luminous efficiency of the organic EL element is limited to about 5% at the maximum (Patent Document 1).

  On the other hand, the phosphorescent emitter has a maximum internal quantum efficiency of 75% because triplet excitons, which are excitons that emit phosphorescence, are formed by 75% of all excitons, and the luminous efficiency of the organic EL element is single. When the contributions of term excitons are combined, a high energy utilization efficiency of up to about 20% can be expected. However, phosphorescence is actually saturated, and energy deactivation between excitons, and its quantum yield is not always high (Patent Document 1).

  Now, fluorescent and thermally activated delayed fluorescent emitters can be expected to have both high internal quantum yield and high external quantum yield due to their emission mechanism. This is because fluorescence and thermally activated delayed fluorescent emitters emit excited singlet excitons that emit fluorescence, while excited triplet excitons also absorb the heat of organic EL devices and atmospheres to produce excited singlets. This is because the fluorescence is emitted by crossing the reverse system.

Therefore, an organic EL element using a light emitting layer that emits strong fluorescence and delayed fluorescence even near room temperature exhibits high luminous efficiency (Non-patent Documents 1-5). Many excellent fluorescent and thermally activated delayed fluorescent emitters that exhibit excellent emission characteristics as the emitter of organic EL elements have already been found (Non-patent Documents 1-7). Fluorescent and heat-activated delayed fluorescent emitters that exhibit excellent emission characteristics as organic EL device emitters have a structure that combines an electron-donating group with a donor property and an electron-withdrawing group with an acceptor property. The electron-donating group having a property and the electron-withdrawing group having an acceptor property have a structure orthogonal to each other due to steric hindrance. At this time, the molecular orbitals of HOMO and LUMO of the present fluorescence and the thermally activated delayed fluorescence emitter hardly overlap each other, and the energy difference (ΔE _ST ) between the singlet and triplet is assumed to be very small ( Non-patent document 8).

WO2011 / 070963

Adachi, C., etal., Nature, 492, 234 (2012) Adachi, C., etal., Angew. Chem. Int. Ed., 51, 11311 (2012) Adachi, C., etal., J. Am. Chem. Soc., 134, 14706 (2012) Adachi, C., etal., Chem. Comm., 48, 9580 (2012) Adachi, C., etal., Chem. Comm., 48, 11392 (2012) Adachi, C., etal., Appl. Phys. Lett., 98,83302 (2011) Adachi, C., etal., Appl. Phys. Lett., 101, 93306 (2012) Adachi, C., etal., Molecular Electronics and Bioelectronics, 24, 19 (2013) Device properties of organic semiconductors, Chihaya Adachi, 2013, 2nd edition, Kodansha, Tokyo Introduction to Organic Electronics, Tetsuo Tsutsui et al., 2012, 1st edition, Nikkan Kogyo Shimbun, Tokyo

  The present invention relates to a fluorescent and thermally activated delayed fluorescent luminescent material exhibiting a high internal quantum yield, and an organic EL exhibiting high external luminous efficiency obtained by using the fluorescent and thermally activated delayed fluorescent luminescent material in the light emitting layer. An object is to provide an element.

  As a result of intensive studies, the present inventors have determined that either one of the donor group and the electron withdrawing group having an acceptor property or a substituent having no clear donor property or acceptor property can be used. Even more, even if it is a planar molecule as a whole, a phosphor emitting remarkable fluorescence and thermally activated delayed fluorescence was obtained. Furthermore, an organic EL device exhibiting excellent light emission characteristics was produced by using the present fluorescence and the thermally activated delayed phosphor in the light emitting layer.

That is, the present invention comprises the following technical means.
[1] A compound having a substituent Xn and a substituent Yn on an aromatic ring of any one of a benzene ring, a naphthalene ring, a biphenyl ring and a fluorene ring, wherein the substituent Xn is benzothiazole, coumarin, or fluorenone , Acridone, quinacridone, acridine, anthraquinone, thioxanthone, phthalimide, naphthyl dicarboimide and pyrene and derivatives thereof, and the substituent Yn is an alkoxyl group, a perfluoroalkoxyl group, a phenoxy group. , A poly or oligoalkyloxy group whose terminal is a hydroxyl group or an alkyloxy group, such as a terminal methoxypolyethyleneoxy group, an alkyl group, a perfluoroalkyl group, or a derivative thereof, and the number of the substituent Xn Is one As described above, the number of the substituents Yn is 0 or more.
[2] The delayed fluorescent light-emitting device according to [1], wherein the number of substituents Xn is 2 to 3, and the number of substituents Yn is 0 to 2.
[3] The aromatic ring is a benzene ring, has an alkoxyl group (Yn) having 1 to 3 C atoms at the 1-position, and has the substituent Xn at the 3-position and the 5-position. The delayed fluorescent material according to [1] or [2].
[4] The aromatic ring is a fluorene ring, has the substituent Xn at any of the 2-position, 2-position and 4-position, and the 2-position and 7-position, and has a methyl group, an ethyl group, or a propyl group at the 9-position. And the delayed fluorescent luminescent material according to [1] or [2] above, which has two phenyl groups (including phenyl group derivatives).
[5] An organic EL device comprising one or more types of delayed fluorescent light emitters according to any one of [1] to [4] in a light emitting layer.

  According to the present invention, it is possible to provide a light emitter that can be expected to have a maximum internal quantum yield of 100% and a maximum light emission efficiency of the organic EL element of 20%. Further, deep blue light emission that cannot be realized by a phosphorescent light emitter is also possible.

An example of the cross section of the organic EL element used by this invention is shown. It is the figure which observed the molecular orbital of LUMO of the compound (4) synthesize | combined in the synthesis example 1 from the point on the plane of a compound (4). FIG. 3 is a diagram of the LUMO molecular orbitals of the compound (4) synthesized in Synthesis Example 1 observed from the vertical direction in FIG. 2. FIG. 3 is a diagram of the HOMO molecular orbital of the compound (4) synthesized in Synthesis Example 1 observed from the vertical direction in FIG. 2.

  The delayed fluorescent substance of the present invention is a fluorescent and thermally activated delayed fluorescent substance, and a substituent Xn and a substituent Yn are added to any aromatic ring among a benzene ring, a naphthalene ring, a biphenyl ring and a fluorene ring. The substituent Xn is selected from any of the residues of benzothiazole, coumarin, fluorenone, acridone, quinacridone, acridine, anthraquinone, thioxanthone, phthalimide, naphthyl dicarboimide and pyrene, and derivatives thereof. The substituent Yn is an alkoxyl group, a perfluoroalkoxyl group, a phenoxy group, a poly or oligoalkyloxy group whose terminal is a hydroxyl group or an alkyloxy group, such as a terminal methoxypolyethyleneoxy group, an alkyl group, and a perfluoroalkyl group. And Selected from any of derivatives, the number of the substituents Xn is 1 or more, wherein the number of said substituents Yn is 0 or more.

  When the aromatic ring is a benzene ring, it is a compound represented by the following chemical formula (1a), the number of substituents Xn is 1 or more, the number of substituents Yn is 0 or more, and the number of (Xn + Yn) Is 6 or less. Among them, the number of substituents Xn is preferably 2 to 3, and the number of substituents Yn is preferably 0 to 2.

  When the aromatic ring is a naphthalene ring, it is a compound represented by the following chemical formula (1b), the number of substituents Xn is 1 or more, the number of substituents Yn is 0 or more, and the number of (Xn + Yn) Is 8 or less. Among them, the number of substituents Xn is preferably 2 to 3, and the number of substituents Yn is preferably 0 to 2.

  When the aromatic ring is a biphenyl ring, it is a compound represented by the following chemical formula (1c), the number of substituents Xn is 1 or more, the number of substituents Yn is 0 or more, and the number of (Xn + Yn) Is 10 or less. Among them, the number of substituents Xn is preferably 2 to 3, and the number of substituents Yn is preferably 0 to 2.

  When the aromatic ring is a fluorene ring, it is a compound represented by the following chemical formula (1d), the number of substituents Xn is 1 or more, the number of substituents Yn is 0 or more, and the number of (Xn + Yn) Is 9 or less, and the 9-position substituent Ym is hydrogen, C is an alkyl group of 4 or less, C is an alkoxy group of 4 or less, phenyl group, naphthyl group, benzyl group, phenethyl group, vinyl group, phenylvinyl group It is a substituent selected from any of these. Among them, the number of substituents Xn is preferably 2 to 3, and the number of substituents Yn is preferably 0 to 2.

  As described above, the substituent Xn is selected from any of the residues of benzothiazole, coumarin, fluorenone, acridone, quinacridone, acridine, anthraquinone, thioxanthone, phthalimide, naphthyl dicarboimide and pyrene, and derivatives thereof. .

  Viscosity adjustment and surface tension adjustment of the composition containing the phosphor by introducing various substituents and residues into the substituent Xn within a range that does not impair the optical properties and light emission properties of the delayed fluorescence phosphor of the present invention. This also contributes to the polarity adjustment of the phosphor itself and the improvement of thermal stability and electrochemical stability.

  Examples of the derivative of the substituent Xn include, for example, an alkoxyl group, a perfluoroalkoxyl group, a phenoxy group, a poly- or oligoalkyloxy group whose terminal is a hydroxyl group or an alkyloxy group, such as a terminal methoxypolyethyleneoxy group. In addition to alkyl groups, perfluoroalkyl groups, phenyl groups, naphthyl groups, benzyl groups, phenethyl groups, vinyl groups, aryl groups such as phenylvinyl groups, amino groups such as diethylamino groups, diphenylamino groups, and ethylphenylamino groups, acetyl groups Residues of various compounds such as esters, amides, imides, ureas, carbonates, urethanes, thiourethanes, ethers, thioethers, acetals, ketals, and sulfones were introduced along with various substituents such as keto groups such as benzoyl groups. Mention may also be made of.

  In particular, for the viscosity adjustment and surface tension adjustment in finishing the delayed fluorescent substance of the present invention into a composition, an alkoxyl group, a perfluoroalkoxyl group, a poly or oligoalkyloxy group having a terminal hydroxyl group or an alkyloxy group, such as a terminal Introduction of a substituent such as a methoxypolyethyleneoxy group into the substituent Xn is effective.

  As described above, the substituent Yn is an alkoxyl group, a perfluoroalkoxyl group, a phenoxy group, a poly or oligoalkyloxy group whose terminal is a hydroxyl group or an alkyloxy group, such as a terminal methoxypolyethyleneoxy group, an alkyl group, and a perfluoro group. An alkyl group and a derivative thereof are selected, but an alkoxyl group, a perfluoroalkoxyl group, and an oligoalkyloxy group whose terminal is a methoxy group are preferable.

  The delayed fluorescent substance of the present invention is not particularly limited as long as it is a compound that emits fluorescence and is thermally activated. Among them, as a more preferable compound as a delayed fluorescent substance, the aromatic ring is a benzene ring. A compound having an alkoxyl group (Yn) having 1 to 3 C atoms at the 1-position and the substituent Xn at the 3-position and 5-position, or the aromatic ring is a fluorene ring; The substituent Xn at any one of the 4-position, 2-position and 7-position, and two methyl groups, ethyl groups, propyl groups and phenyl groups (including phenyl group derivatives) at the 9-position It is a compound that has.

  The present invention also relates to an organic EL device characterized by having a light emitting layer containing the above-described fluorescence and thermally activated delayed fluorescent light emitter and exhibiting a high external quantum yield.

  Next, the layer structure of the organic EL element of the present invention will be described (see FIG. 1). FIG. 1 schematically shows the layer structure of the organic EL element used in the present invention. Reference numeral 1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light emitting layer, 6 denotes an electron transport layer, 7 denotes an electron injection layer, and 8 denotes a cathode. Note that the four layers of the anode, the hole transport layer, the light emitting layer, and the cathode in this figure are indispensable layers for functioning the organic EL device of the present invention. Below, each layer which comprises an organic EL element is demonstrated.

  First, the characteristics of the substrate are required to be transparent and smooth. A total light transmittance of at least 70% or more, preferably 80%, more preferably 90% or more is required. Since several thin films such as an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode, which will be described later, are laminated, smoothness on the order of nanometers is required. Of course, the thinner the thin film that is laminated, the higher the level of smoothness that is required. Furthermore, the lower the permeability of gas such as oxygen and water vapor, the better. This is because a laminated thin film mainly composed of an organic substance sandwiched between both electrodes constituting an organic EL element is never stable when a voltage is applied to oxygen or water vapor. Furthermore, with the recent trend of pursuing a flexible display, a flexible transparent substrate is also required, and a glass substrate having a thickness of several μm or a special transparent plastic is used.

The thin film formed on the substrate is laminated by a vacuum deposition method or a coating method. The vacuum deposition method is carried out by heating the compound to be deposited in an atmosphere reduced to 10 ⁻³ Pa or less, preferably 10 ⁻⁴ Pa or less. Regarding the thickness of each layer, the anode and cathode are often formed around 100 nm, and the other layers including the light emitting layer are formed thinner than 50 nm. However, the optimum film thickness varies depending on the type of layer and the compound used. For example, the electron injection layer or the like is often formed to an ultra-thickness of 1 nm or less.

  The electrode is provided with the anode and the cathode facing each other. As the anode, a substance having a high work function is preferable. To transmit light emitted from the anode, transparent conductive ceramics such as ITO and ZnO, transparent conductive polymers such as PEDOT / PSS and polyaniline, and transparent conductive materials such as nanowires and nanoparticles of silver and copper are used. It is done. In addition to vapor deposition and sputtering, film formation by printing and coating is also possible. The sheet resistance is several hundred Ω / □ or less, and the total light transmittance is preferably 80% or more, more preferably 90% or more. The film thickness is usually selected from 10 to 1000 nm, preferably from 10 to 200 nm.

The cathode is a mixture of an electron injecting metal having a low work function and a stable second metal having a higher work function value, such as a magnesium / aluminum mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium / An aluminum mixture or the like is suitable, and film formation by vapor deposition or sputtering is possible. The sheet resistance is selected from several hundred Ω / □ or less, and the film thickness is usually selected from 10 nm to 5 μm, preferably 50 to 200 nm.

In the light emitting layer, it is preferable to use a host compound together with the light emitter of the present invention, as well as other light emitters used in the organic EL device. As the host compound, select a compound that suppresses the concentration quenching of this phosphor, contributes to the movement of charges such as holes and electrons, and does not impair the emission characteristics of fluorescent and thermally activated delayed fluorescent emitters. Is done. Furthermore, a high glass transition temperature (Tg) and electrochemical stability which are thermally stable are also required. Of the components constituting the light emitting layer, the content of the fluorescent and thermally activated delayed fluorescent material of the present invention is often 1 to 50% by weight, preferably 1 to 20% by weight.
Examples of the host compound include CBP, PPT, adamantane anthracene, TBAND, rubrene, and TPBA (Non-Patent Document 9).

In order to efficiently transport holes from the anode to the light emitting layer, a hole transport layer is provided between the anode and the light emitting layer. Examples of the hole transport material forming the hole transport layer include TAPC, TPD, α-NPD, mCP, PTE, and Spiro-TAD (Non-patent Document 10).
In order to efficiently transport electrons from the cathode to the light emitting layer, an electron transporting layer is provided between the cathode and the light emitting layer. Examples of the electron transport material forming the electron transport layer include tBu-PBD, OXD-7, TAZ, BCP, TPQ, TPBi, PPT, and B3PymPm (Non-Patent Document 10).
In addition to the above-described layers, various thin layers such as a hole injection layer and an electron injection layer, and a hole blocking layer, an electron blocking layer, and an exciton blocking layer are formed as necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples, It is possible to implement in a various form, unless the summary is exceeded.

[Synthesis Example 1]
The following compound (4) which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 2 (molecular weight 148), 148 mg (1.00 mmol), compound 3 (molecular weight 110), 49.5 mg (0.45 mmol), and about 20 mL of dehydrated DMF were charged vigorously with a magnetic stirrer. The solution was stirred. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 150 ° C. for 6 hours. Thereafter, the reaction mixture was allowed to cool to room temperature and the volatile components in the reaction solution were removed by a rotary evaporator to obtain a solid component. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a mixed solvent of hexane: ethyl acetate = 6: 4 v: v as small as possible at 50 ° C. and naturally filtered with filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were removed by filtration and dried in a vacuum dryer at 50 ° C. for 1 day to obtain 182 mg (yield 55.2%) of the desired compound, methoxyphenylene-3,5-bisphthalimide (4) (molecular weight 330). Obtained. 1HNMR: 3.8 ppm, s, 3H, 7.1 ppm, s, 3H, 7.5 ppm, d, 2H, 7.8 ppm, t, 2H.

  2 and 3 show LUMO molecular orbitals derived by ab initio molecular orbital calculation using Gaussian 09W of methoxyphenylene-3,5-bisphthalimide (4) synthesized in Synthesis Example 1. FIG. A diagram of the molecular orbitals of HOMO is shown in FIG.

FIG. 2 is a diagram in which the molecular orbitals of LUMO formed by the compound (4) are observed from a certain point on the plane of the compound (4). The compound (4) is planar and the electron cloud is concentrated on one side. You can see that.
FIG. 3 is a diagram in which the molecular orbitals of LUMO formed by the compound (4) are observed from the direction perpendicular to the plane (the vertical direction in FIG. 2). The electron cloud is concentrated on the upper part of the compound (4). Can be seen.
FIG. 4 is a diagram in which the molecular orbitals of HOMO formed by the compound (4) are observed from the direction perpendicular to the plane (the vertical direction in FIG. 2), and the electron cloud is concentrated at the center of the compound (4). I can see that.
Compared with FIG. 3 and FIG. 4, which are diagrams of the compound (4) observed from the vertical direction, the LUMO molecular orbitals are concentrated on one side of the compound (4), and the HOMO molecular orbitals are the compound (4). It can be seen that the molecular orbitals hardly overlap in LUMO and HOMO.

[Synthesis Example 2]
The following compound (6), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 5 (molecular weight 198), 198 mg (1.00 mmol), compound 3 (molecular weight 110), 49.5 mg (0.45 mmol), and about 20 mL of dehydrated DMF were charged vigorously with a magnetic stirrer. The solution was stirred. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 150 ° C. for 6 hours. Thereafter, the reaction mixture was allowed to cool to room temperature and the volatile components in the reaction solution were removed by a rotary evaporator to obtain a solid component. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a mixed solvent of hexane: ethyl acetate = 6: 4 v: v as small as possible at 50 ° C. and naturally filtered with filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were taken out by filtration and dried in a vacuum dryer at 50 ° C. for 1 day to obtain 232 mg (yield 48.5) of the target compound, methoxyphenylene-3,5-bisnaphthyldicarboimide (6) (molecular weight 478). %)Obtained. 1HNMR: 3.8 ppm, s, 3H, 7.1 ppm, s, 3H, 7.5 ppm, d, 2H, 7.8 ppm, t, 2H.

[Synthesis Example 3]
The following compound (9), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 7 (molecular weight 258), 258 mg (1.00 mmol), compound 8 (molecular weight 357), 161 mg (0.45 mmol), Pd (PPh3) 4, 4.19 mg (1.00 wt% vs. reaction) Product), Aliquot, 21.0 mg (5.00% by weight with respect to the reactant), 15 mL of toluene, and about 10 g of a 5% by weight aqueous solution of potassium carbonate (molecular weight 138) were stirred vigorously with a magnetic stirrer to obtain a solution. Here, about 20 mL of a 10 wt% CaCO3 aqueous solution prepared in advance was added to the round bottom flask, and stirring was continued. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 70 ° C. for 5 hours. Thereafter, the toluene layer of the reaction solution which was allowed to cool to room temperature was dehydrated with an appropriate amount of MgSO 4, and the volatile matter was removed with a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a small amount of a mixed solvent of hexane: ethyl acetate = 9: 1 v: v at 50 ° C. and naturally filtered through a filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were taken out by filtration and dried in a vacuum dryer at 50 ° C. for 1 day to obtain 88.3 mg (yield) of the target compound 3,5-di-2-pyrenylmethoxybenzene (9) (molecular weight 462). 42.5%). 1HNMR: 3.8 ppm, s, 3H, 7.0-7.3 ppm, s, 5H, 7.6 ppm, d, 4H, 7.8 ppm, t, 4H.

[Synthesis Example 4]
The following compound (11), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 10 (molecular weight 287), 287 mg (1.00 mmol), compound 8 (molecular weight 357), 161 mg (0.45 mmol), Pd (PPh 3) 4, 4.48 mg (1.00 wt% vs. reaction) Product), Aliquot, 22.4 mg (5.00% by weight with respect to the reaction product), 10 mL of toluene, and about 10 g of a 5% by weight aqueous solution of potassium carbonate (molecular weight 138), were vigorously stirred with a magnetic stirrer to obtain a solution. Here, about 20 mL of a 10 wt% CaCO3 aqueous solution prepared in advance was added to the round bottom flask, and stirring was continued. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 70 ° C. for 5 hours. Thereafter, the toluene layer of the reaction solution which was allowed to cool to room temperature was dehydrated with an appropriate amount of MgSO 4, and the volatile matter was removed with a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a small amount of a mixed solvent of hexane: ethyl acetate = 9: 1 v: v at 50 ° C. and naturally filtered through a filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were taken out by filtration and dried in a vacuum dryer at 50 ° C. for 1 day, and the target compound, 3,5-di-2-anthraquinonylmethoxybenzene (11) (molecular weight 472), 245 mg (yield 51) 9%). 1HNMR: 3.7ppm, s, 3H, 7.1ppm, s, 3H, 7.3ppm, s, 2H, 7.5ppm, d, 8H, 7.9ppm, t, 4H.

[Synthesis Example 5]
The following compound (13), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 12 (molecular weight 291), 291 mg (1.00 mmol), compound 8 (molecular weight 357), 161 mg (0.45 mmol), Pd (PPh3) 4, 4.52 mg (1.00 wt% vs. reaction) ), Aliquot, 22.6 mg (5.00% by weight with respect to the reaction product), 10 mL of toluene, and about 10 g of a 5% by weight aqueous solution of potassium carbonate (molecular weight 138), and vigorously stirred with a magnetic stirrer to obtain a solution. Here, about 20 mL of a 10 wt% CaCO3 aqueous solution prepared in advance was added to the round bottom flask, and stirring was continued. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 70 ° C. for 5 hours. Thereafter, the toluene layer of the reaction solution which was allowed to cool to room temperature was dehydrated with an appropriate amount of MgSO 4, and the volatile matter was removed with a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a small amount of a mixed solvent of hexane: ethyl acetate = 9: 1 v: v at 50 ° C. and naturally filtered through a filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were taken out by filtration and dried in a vacuum dryer at 50 ° C. for 1 day, and the target compound 3,5-di-2-thioxanthonylmethoxybenzene (13) (molecular weight 504), 148 mg (yield 29) 4%). 1HNMR: 3.5 ppm, s, 3H, 7.1 ppm, s, 3H, 7.2 ppm, s, 2H, 7.5 ppm, d, 8H, 7.9 ppm, t, 4H.

[Synthesis Example 6]
The following compound (15), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 14 (molecular weight 258), 258 mg (1.00 mmol), compound 8 (molecular weight 357), 161 mg (0.45 mmol), Pd (PPh3) 4, 4.19 mg (1.00 wt% vs. reaction) Product), Aliquot, 21.0 mg (5.00% by weight with respect to the reaction product), 10 mL of toluene, and about 10 g of a 5% by weight aqueous solution of potassium carbonate (molecular weight 138), were vigorously stirred with a magnetic stirrer to obtain a solution. Here, about 20 mL of a 10 wt% CaCO3 aqueous solution prepared in advance was added to the round bottom flask, and stirring was continued. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 70 ° C. for 5 hours. Thereafter, the toluene layer of the reaction solution which was allowed to cool to room temperature was dehydrated with an appropriate amount of MgSO 4, and the volatile matter was removed with a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a small amount of a mixed solvent of hexane: ethyl acetate = 9: 1 v: v at 50 ° C. and naturally filtered through a filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were collected by filtration and dried in a vacuum dryer at 50 ° C. for 1 day, and the target compound, 3,5-di-2-acridinylmethoxybenzene (15) (molecular weight 462), 88.3 mg (yield). (Rate 42.5%). 1HNMR: 3.8 ppm, s, 3H, 7.0-7.3 ppm, s, 5H, 7.6 ppm, d, 4H, 7.8 ppm, t, 4H.

[Synthesis Example 7]
The following compound (17), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. In a round bottom flask, compound 16 (molecular weight 258), 258 mg (1.00 mmol), compound 8 (molecular weight 357), 161 mg (0.45 mmol), Pd (PPh3) 4, 4.19 mg (1.00 wt% vs. reaction) Product), Aliquot, 21.0 mg (5.00% by weight with respect to the reaction product), 10 mL of toluene, and about 10 g of a 5% by weight aqueous solution of potassium carbonate (molecular weight 138), were vigorously stirred with a magnetic stirrer to obtain a solution. Here, about 20 mL of a 10 wt% CaCO3 aqueous solution prepared in advance was added to the round bottom flask, and stirring was continued. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 70 ° C. for 5 hours. Thereafter, the toluene layer of the reaction solution which was allowed to cool to room temperature was dehydrated with an appropriate amount of MgSO 4, and the volatile matter was removed with a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a small amount of a mixed solvent of hexane: ethyl acetate = 9: 1 v: v at 50 ° C. and naturally filtered through a filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were removed by filtration and dried in a vacuum dryer at 50 ° C. for 1 day, and the target compound, 3,5-di-2-fluoronylmethoxybenzene (17) (molecular weight 462), 295 mg (yield 63) 8%). 1HNMR: 3.8 ppm, s, 3H, 7.0-7.3 ppm, s, 5H, 7.6 ppm, d, 4H, 7.8 ppm, t, 4H.

[Synthesis Example 8]
The following compound (19), which is one of the fluorescent and thermally activated delayed fluorescent materials provided by the present invention, was prepared. The synthesis procedure is as follows. A stirring bar was placed in a four-necked round-bottom flask having an internal volume of 100 mL, and a three-way cock with a condenser, a thermometer, and a balloon filled with nitrogen gas was attached. A round bottom flask was charged with compound 18 (molecular weight 220), 220 mg (1.00 mmol), compound 2 (molecular weight 148), 66.6 mg (0.45 mmol), and about 20 mL of dehydrated DMF, and vigorously stirred with a magnetic stirrer. The solution was stirred. The inside of the round bottom flask was purged with nitrogen by blowing nitrogen into the flask at 50 mL / min for 20 minutes. When the nitrogen blowing was finished, the cooling tube tip was sealed with nitrogen. While stirring, the round bottom flask was immersed in an oil bath, and the solution in the flask was kept warm at about 150 ° C. for 6 hours. Thereafter, the reaction mixture was allowed to cool to room temperature and the volatile components in the reaction solution were removed by a rotary evaporator to obtain a solid component. The obtained solid content was dissolved in about 10 mL of dichloromethane, and the volatile content of the eluate obtained through a short column filled with silica gel was removed by a rotary evaporator to obtain a solid content. The obtained solid content was dissolved in a mixed solvent of hexane: ethyl acetate = 6: 4 v: v as small as possible at 50 ° C. and naturally filtered with filter paper using a Nutsche and a filter bottle maintained at 50 ° C. It was. The obtained 50 ° C. filtrate was transferred to an Erlenmeyer flask that had been kept warm at 50 ° C., sealed up, and allowed to stand overnight at room temperature. The precipitated crystals were removed by filtration and dried in a vacuum dryer at 50 ° C. for 1 day, and the target compound, 9,9-dimethylfluorene-2,7-bisbenzimide (19) (molecular weight 480), 187 mg (yield) 38.9%). 1HNMR: 3.8 ppm, s, 3H, 7.1 ppm, s, 3H, 7.5 ppm, d, 2H, 7.8 ppm, t, 2H.

[Example 1]
Each thin film was laminated | stacked by the vacuum evaporation method on the glass substrate in which the anode which consists of ITO with a film thickness of 100 nm was formed. First, α-NPD was formed on ITO to a thickness of 40 nm, and then mCD was formed to a thickness of 10 nm. Next, the compound (4) and PPT were co-evaporated to form a thickness of 20 nm. At this time, the concentration of the compound (4) was about 5.0% w / w. Next, PPT was formed to a thickness of 40 nm, and subsequently LiF was formed to a thickness of 0.8 nm. Finally, aluminum was formed to a thickness of 70 nm as a cathode to obtain an organic EL element. By applying a direct current at 300 K to the obtained organic EL element, 453 nm emission derived from the compound (4) was confirmed. At this time, when the external luminous efficiency was measured using an absolute quantum yield measuring apparatus (C9920-02, manufactured by Hamamatsu Photonics), it was 18% at a current density of 0.01 mA / cm 2.

  Furthermore, the ratio of fluorescence and thermally activated delayed fluorescence was determined by performing time-resolved spectrum measurement with a streak camera (C4334, manufactured by Hamamatsu Photonics). In Table 1, the values obtained by dividing the fluorescence emission amount by the total emission amount (fluorescence component (%)) are shown in Table 1, where the emission lifetime is shorter than 2 μsec, while the longer emission component is delayed fluorescence. In this example, the fluorescent component was 25%. The results are shown in Table 1 together with the emission wavelength and the external emission efficiency.

[Examples 2 to 8]
In Examples 2 to 8, Example 1 except that compounds (6), (9), (11), (13), (15), (17) and (19) were used instead of compound (4). The same operation was performed. The emission wavelength, the external emission efficiency, and the fluorescence emission amount derived from the compounds (6), (9), (11), (13), (15), (17) and (19) are expressed as the total emission amount. The divided value (fluorescent component (%)) is shown in Table 1.

The organic EL device of the present invention using the fluorescent and delayed fluorescent emitters of the present invention in its light emitting layer has both excellent optical characteristics / light emitting characteristics and low power consumption. Therefore, the organic EL device can be used for a wall-mounted television, a flat panel display for a computer, a mobile phone screen, and the like. Furthermore, it is expected to be applied to various light sources and various illuminations from the backlight of liquid crystal displays to indoor and outdoor lighting.

Claims (5)

  A compound having a substituent Xn and a substituent Yn on an aromatic ring of any one of a benzene ring, a naphthalene ring, a biphenyl ring and a fluorene ring, wherein the substituent Xn is benzothiazole, coumarin, fluorenone, acridone, It is selected from any of the residues of quinacridone, acridine, anthraquinone, thioxanthone, phthalimide, naphthyl dicarbimide and pyrene and derivatives thereof, and the substituent Yn is an alkoxyl group, a perfluoroalkoxyl group, a phenoxy group, and a terminal. A poly or oligoalkyloxy group that is a hydroxyl group or an alkyloxy group, such as a terminal methoxypolyethyleneoxy group, an alkyl group, a perfluoroalkyl group, or a derivative thereof, and the number of the substituent Xn is one. that's all, Delayed fluorescence material, wherein the number of serial substituents Yn is 0 or more.   2. The delayed fluorescence emitter according to claim 1, wherein the number of the substituents Xn is 2 to 3, and the number of the substituents Yn is 0 to 2. 3.   2. The aromatic ring is a benzene ring, having an alkoxyl group (Yn) having 1 to 3 C atoms at the 1-position, and having the substituent Xn at the 3-position and 5-position. Alternatively, the delayed fluorescent substance according to claim 2.   The aromatic ring is a fluorene ring, has the substituent Xn at any one of the 2-position, 2-position and 4-position, 2-position and 7-position, and has a methyl group, ethyl group, propyl group and phenyl group at the 9-position. The delayed fluorescent substance according to claim 1 or 2, comprising any two of (including a derivative of a phenyl group). An organic EL device comprising one or more types of delayed fluorescent light emitters according to any one of claims 1 to 4 in a light emitting layer.