KR20220098515A - Delayed fluorescence compound and organic light emitting device comprising the same - Google Patents

Abstract

The present specification relates to a delayed fluorescence compound represented by chemical formula 1, a delayed fluorescence organic light emitting device including the same, and a super fluorescence organic light emitting device further including a fluorescence dopant compound, wherein the delayed fluorescence compound implements a dark blue light emitting spectrum having a narrower half width compared to a conventional delayed fluorescence material, and excellent life characteristics.

Description

DELAYED FLUORESCENCE COMPOUND AND ORGANIC LIGHT EMITTING DEVICE COMPRISING THE SAME

The present invention relates to a delayed fluorescence compound and an organic light emitting device comprising the same, and more particularly, a compound exhibiting thermally activated delayed fluorescence (TADF) characteristics, a delayed fluorescence organic light emitting device comprising the same, and the compound; It relates to a hyperfluorescence organic light emitting device including a fluorescent dopant compound.

Organic light emission refers to a phenomenon in which electric energy is converted into light energy using an organic material. An organic light emitting device (OLED) is manufactured by interposing an organic material between an anode and a cathode by using such organic light emission, and has a characteristic of emitting light when electric energy is applied. An organic light emitting device includes a multi-layered organic layer to improve efficiency and stability, and generally a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer, and an electron transport layer (ETL). ), and an electron injection layer (EIL).

Materials used as organic layers can be classified into light emitting materials and charge transport materials according to their functions. It can be classified into a fluorescent material and a phosphorescent material using a phosphorescence phenomenon derived from a triplet exited state. In addition, the light emitting material may be divided into blue, green, and red light emitting materials according to the emission color, and phosphorescent materials have been developed and used in the industry for the other colors except for blue. However, in the case of blue materials, only fluorescent materials are used due to limitations in lifespan and color characteristics. Blue phosphorescent materials using triplets using heavy metals such as iridium or platinum, and pure organic materials by making the difference between singlet and triplet energy small. Delayed fluorescence materials using triplets and the like are being developed. However, high efficiency can be achieved when phosphors using heavy metals are used, but economical efficiency is insufficient due to heavy metals for phosphorescence, and there are difficulties in mining due to social problems.

Therefore, interest in delayed fluorescence materials is increasing, and research is being conducted on various color gamuts such as green, yellow, orange, and red, not limited to blue. Unlike conventional fluorescence, in which 75% of triplet energy is lost using only singlet energy, delayed fluorescence is designed so that the energy difference between singlet and triplet is small. By inducing the phenomenon of Reverse Inter-system Crossing to occur, the energy of all triplets and singlets can be utilized. Therefore, since triplets can be used without heavy metal materials like phosphorescent materials, the efficiency of the material is higher than that of fluorescent materials.

The characteristics of the organic light emitting diode may depend on the dopant material of the emission layer, and the delayed fluorescence dopant is used to minimize the energy difference between the singlet and the triplet. ) should have little overlap. For this purpose, a donor-acceptor structure is mainly used, and in the case of the structure, there is a problem in that the electroluminescence spectrum is broadened due to the light emission method through intra charge transfer in the molecule. Therefore, when the conventional donor-acceptor structure compound is applied as a delayed fluorescent material, there is a disadvantage in that the emission spectrum is wide and the color purity is inferior.

In addition, by introducing a substituent, the light emission wavelength can be changed by controlling the strength of the donor or acceptor to control the charge transfer characteristics in the molecule. However, there is a problem in that the substituent to which the substituent is bonded is easily deteriorated, and thus the lifespan characteristics of the device are inferior.

SUMMARY OF THE INVENTION The present invention is to solve the problems of the prior art, and an object of the present invention is to provide a delayed fluorescent compound having improved color characteristics while maintaining lifespan characteristics using specific substituents.

Another object of the present invention is to provide an organic light emitting device including a long-life delayed fluorescent compound having improved color characteristics by shifting the emission wavelength to a shorter wavelength.

In addition, another object of the present invention is to provide an organic light emitting device that includes the above-described compound and a fluorescent dopant compound and exhibits ultra-fluorescent properties of long lifespan and high color purity.

One aspect of the present invention provides a delayed fluorescence compound represented by the following formula (1):

[Formula 1]

In Formula 1, D ₁ is represented by Formulas 2 to 4,

[Formula 2]

[Formula 3]

[Formula 4]

In the above formula, A ₁ To A ₇ are each independently a substituted or unsubstituted C ₅ ~ C ₆₀ carbocyclic group, a substituted or unsubstituted C ₂ ~ C ₆₀ heterocyclic group, C ₆ ~ C ₆₀ A ring structure selected from an aryl group and a C ₅ ~ C ₆₀ heteroaryl group, R ₁ to R ₆ are each independently hydrogen, deuterium, a straight-chain or branched alkyl group substituted with deuterium, a substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group, substituted or unsubstituted C ₃ ~ C ₆₀ cycloalkyl group, substituted or unsubstituted C ₃ ~C ₆₀ silyl group, substituted or unsubstituted C ₂ ~ C ₆₀ heterocyclic group, substituted or unsubstituted A pentagon including one selected from a cyclic C ₆ ~ C ₆₀ aryl group, a substituted or unsubstituted C ₅ ~ C ₆₀ heteroaryl group, or O, S, and NR ₁₄ formed by bonding two adjacent substituents to each other is a heteroaryl ring structure of, Y ₁ To Y ₂ are each independently hydrogen or bonded to each other to form a ring, Y ₃ To Y ₅ are each independently O, S, NR ₁₅ and C-(R ₁₆ ) ₂ is one selected, and R ₇ to R ₁₃ are each independently hydrogen, deuterium, a nitrile group, a halogen group, a substituted or unsubstituted C ₁ to C ₆₀ alkyl group, a substituted or unsubstituted C ₃ to C ₆₀ cycloalkyl group, a substituted or Unsubstituted C ₁ -C ₆₀ alkoxy group, substituted or unsubstituted C ₃ -C ₆₀ silyl group, substituted or unsubstituted C ₆ -C ₆₀ aryl group, and substituted or unsubstituted C ₆ -C ₆₀ heteroaryl selected from a group, a substituted or unsubstituted C ₆ -C ₆₀ diarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ diheteroarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ arylheteroarylamino group, R ₁₄ to R ₁₆ are each hydrogen, deuterium, a substituted or unsubstituted C ₁ -C ₆₀ alkyl group, a substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₆ -C ₆₀ aryl group, and substitution or an unsubstituted C ₆ -C ₆₀ heteroaryl group.

In one embodiment, it may be represented by any one of the following Chemical Formulas T-1 to T-179:

.

.

Another aspect of the present invention, the first electrode; a second electrode provided to face the first electrode; and at least one functional layer interposed between the first electrode and the second electrode, wherein at least one of the functional layers contains the delayed fluorescent compound according to any one of claims 1 to 2 Provided is an organic light emitting device, which is a light emitting layer including more than one type.

In an embodiment, the light emitting layer may further include a fluorescent dopant compound represented by the following Chemical Formula 5 or Chemical Formula 6:

[Formula 5]

[Formula 6]

In the above formula, R ₁₇ to R ₂₅ are each independently hydrogen, deuterium, halogen, hydroxyl group, cyano group, nitro group, amino group, amidino group, hydrazino group, hydrazono group, substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group, substituted or unsubstituted C ₂ ~C ₆₀ alkenyl group, substituted or unsubstituted C ₂ ~C ₆₀ alkynyl group, substituted or unsubstituted C ₁ ~C ₆₀ alkoxy group, substituted or unsubstituted C ₃ ~C ₁₀ cycloalkyl group, substituted or unsubstituted C ₂ ~C ₁₀ heterocycloalkyl group, substituted or unsubstituted C ₃ ~C ₁₀ cycloalkenyl group, substituted or unsubstituted C ₂ ~C ₁₀ heterocycloalkenyl group, substituted Or unsubstituted C ₆ ~ C ₆₀ aryl group, substituted or unsubstituted C ₆ ~ C ₆₀ aryloxy group, substituted or unsubstituted C ₆ ~ C ₆₀ arylthio group, substituted or unsubstituted C ₁ ~ C ₆₀ A heteroaryl group, a substituted or unsubstituted C ₁ ~ C ₆₀ heteroaryloxy group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and , Y ₆ To Y ₉ are each independently hydrogen, or combine with each other to form a ring.

In one embodiment, the fluorescent dopant fluorescent compound may be represented by any one of the following Chemical Formulas F-1 to F-51:

.

.

In an embodiment, the first electrode is an anode, the second electrode is a cathode, and the functional layer is interposed between the first electrode and the light emitting layer, and among a hole injection layer, a hole transport layer and an electron blocking layer. a hole transport region including at least one; and an electron transport region interposed between the light emitting layer and the second electrode and including at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

According to one aspect of the present invention, it is possible to provide a delayed fluorescent compound that maintains lifespan characteristics while improving color characteristics by providing a specific substituent to the acceptor.

According to another aspect of the present invention, it is possible to provide an organic light emitting device having a long lifespan of blue color including the compound described above.

In addition, according to another aspect of the present invention, it is possible to provide a delayed fluorescence photosensitive superfluorescent device including the above-described compound and a fluorescent dopant compound.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a graph showing the properties of a boron compound according to an embodiment of the present invention,
Figure 2 is a graph showing the properties of the boron compound according to an embodiment of the present invention,
3 is a graph showing the properties of a boron compound according to an embodiment of the present invention,
4 is a graph showing characteristics of an organic light emitting device including a boron compound according to an embodiment of the present invention;
5 is a graph showing characteristics of an organic light-emitting device including a boron compound according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected" with another part, this includes not only the case of being "directly connected" but also the case of being "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

When a range of numerical values is recited herein, the values have the precision of the significant figures provided in accordance with the standard rules in chemistry for significant figures, unless the specific range is otherwise stated. For example, 10 includes the range of 5.0 to 14.9 and the number 10.0 includes the range of 9.50 to 10.49.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

delayed fluorescence compound

The delayed fluorescent compound according to an aspect of the present invention may be represented by the following Chemical Formula 1:

[Formula 1]

In Formula 1, D ₁ is represented by Formulas 2 to 4,

[Formula 2]

[Formula 3]

[Formula 4]

In the above formula, A ₁ To A ₇ are each independently a substituted or unsubstituted C ₅ ~ C ₆₀ carbocyclic group, a substituted or unsubstituted C ₂ ~ C ₆₀ heterocyclic group, C ₆ ~ C ₆₀ A ring structure selected from an aryl group and a C ₅ ~ C ₆₀ heteroaryl group, R ₁ to R ₆ are each independently hydrogen, deuterium, a straight-chain or branched alkyl group substituted with deuterium, a substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group, substituted or unsubstituted C ₃ ~ C ₆₀ cycloalkyl group, substituted or unsubstituted C ₃ ~C ₆₀ silyl group, substituted or unsubstituted C ₂ ~ C ₆₀ heterocyclic group, substituted or unsubstituted A pentagon including one selected from a cyclic C ₆ ~ C ₆₀ aryl group, a substituted or unsubstituted C ₅ ~ C ₆₀ heteroaryl group, or O, S, and NR ₁₄ formed by bonding two adjacent substituents to each other is a heteroaryl ring structure of, Y ₁ To Y ₂ are each independently hydrogen or bonded to each other to form a ring, Y ₃ To Y ₅ are each independently O, S, NR ₁₅ and C-(R ₁₆ ) ₂ is one selected, and R ₇ to R ₁₃ are each independently hydrogen, deuterium, a nitrile group, a halogen group, a substituted or unsubstituted C ₁ to C ₆₀ alkyl group, a substituted or unsubstituted C ₃ to C ₆₀ cycloalkyl group, a substituted or Unsubstituted C ₁ -C ₆₀ alkoxy group, substituted or unsubstituted C ₃ -C ₆₀ silyl group, substituted or unsubstituted C ₆ -C ₆₀ aryl group, and substituted or unsubstituted C ₆ -C ₆₀ heteroaryl selected from a group, a substituted or unsubstituted C ₆ -C ₆₀ diarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ diheteroarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ arylheteroarylamino group, R ₁₄ to R ₁₆ are each hydrogen, deuterium, a substituted or unsubstituted C ₁ -C ₆₀ alkyl group, a substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₆ -C ₆₀ aryl group, and substitution or an unsubstituted C ₆ -C ₆₀ heteroaryl group.

In the above description, the unsubstituted functional group may be composed of carbon and hydrogen except for a structure essential for a specific functional group, and the substituted functional group indicates that at least one of carbon in the unsubstituted functional group is substituted with an atom other than carbon. can mean Examples of such substitution atoms include, but are not limited to, deuterium, nitrogen, sulfur, oxygen, silicon, and halogen elements.

The compound represented by Formula 1 may have delayed fluorescence properties by including a BO structure acceptor and various donors in which the functional groups represented by Formulas 2 to 4 are connected by a C-N bond.

When a substituent having electron donor properties, for example, a t-butyl group, a methyl group, etc. is combined with the boron acceptor structure, the electron withdrawing ability of the boron located in the center is weakened and the band gap is increased, Conversely, when phenyl with electron accepting properties is combined, the electron-withdrawing ability of boron is strengthened and the band gap can be reduced. In particular, the electron donor ability of the substituent may be expressed differently depending on the position of the substituent with respect to boron. For example, if a substituent is attached at the para-position rather than the meta-position of boron, the electron donor ability is more effectively expressed, and thus the ability to attract electrons of the boron acceptor structure may be further weakened.

When a substituent having electron donor properties is coupled to the boron acceptor structure, the strength of the acceptor decreases and the band gap increases, and the charge transfer characteristic in the molecule, which is the light emitting mechanism of delayed fluorescence, is weakened, so that the half width narrows and color characteristics can be improved.

The compound represented by the formula (1) increases the band gap by reducing the ability to attract electrons by binding a substituent having an electron donor property to the acceptor of the BO structure, thereby realizing a dark blue light emitting property, and weakening the intramolecular charge transfer property It is possible to improve the color characteristics by reducing the half width.

If the substituent is a branched alkyl group containing secondary or tertiary carbon, for example, an isopropyl group, a t-butyl group, or an electron donor group connected by a CN bond, the compound deteriorates when applied to an organic light emitting device, resulting in lifetime properties may be degraded. Such deterioration can easily occur in a quaternary carbon, for example, a terminal bond of a t-butyl group, a CN bond, and the like. Accordingly, as R ₁ to R ₆ , a straight-chain or branched alkyl group in which the carbon bonded to the acceptor of the BO structure is a primary carbon, a straight-chain or branched alkyl group substituted with deuterium, a cycloalkyl group, a silyl group , if a substituent having an electron donor property consisting of a CC bond, for example, carbazole or dibenzofuran, is used, it is moved to a shorter wavelength to realize blue light emission properties and at the same time, it is possible to prevent deterioration of lifespan properties due to deterioration of the substituent. This color characteristic improvement can be implemented more effectively when the electron donor group is replaced at the para-position compared to the meta-position of boron.

In one example, the delayed fluorescent compound may be represented by any one of the following Chemical Formulas T-1 to T-179:

.

.

An organic light emitting diode according to another aspect of the present invention includes: a first electrode; a second electrode provided to face the first electrode; and one or more functional layers interposed between the first electrode and the second electrode, wherein one or more of the functional layers may be a light emitting layer including one or more of the delayed fluorescent compounds described above.

The organic light-emitting device may be a delayed-fluorescence organic light-emitting device having superior efficiency compared to a conventional fluorescent device by including the compound represented by Formula 1 having delayed fluorescence properties in an emission layer. The emission layer may further include a host compound, and the compound of Formula 1 may act as a delayed fluorescence dopant.

In another example, the light emitting layer may further include a fluorescent dopant compound represented by the following Chemical Formula 5 or Chemical Formula 6:

[Formula 5]

[Formula 6]

In the above formula, R ₁₇ to R ₂₅ are each independently hydrogen, deuterium, halogen, hydroxyl group, cyano group, nitro group, amino group, amidino group, hydrazino group, hydrazono group, substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group, substituted or unsubstituted C ₂ ~C ₆₀ alkenyl group, substituted or unsubstituted C ₂ ~C ₆₀ alkynyl group, substituted or unsubstituted C ₁ ~C ₆₀ alkoxy group, substituted or unsubstituted C ₃ ~C ₁₀ cycloalkyl group, substituted or unsubstituted C ₂ ~C ₁₀ heterocycloalkyl group, substituted or unsubstituted C ₃ ~C ₁₀ cycloalkenyl group, substituted or unsubstituted C ₂ ~C ₁₀ heterocycloalkenyl group, substituted Or unsubstituted C ₆ ~ C ₆₀ aryl group, substituted or unsubstituted C ₆ ~ C ₆₀ aryloxy group, substituted or unsubstituted C ₆ ~ C ₆₀ arylthio group, substituted or unsubstituted C ₁ ~ C ₆₀ A heteroaryl group, a substituted or unsubstituted C ₁ ~ C ₆₀ heteroaryloxy group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and , Y ₆ To Y ₉ are each independently hydrogen, or combine with each other to form a ring.

When the light emitting layer includes the delayed fluorescent compound represented by Formula 1 and the compound represented by Formula 5 or Formula 6, the delayed fluorescent compound acts as a kind of host to form excitons, and these excitons are represented by Formula 5 or Formula 6 The superfluorescent property can be realized by migrating to a compound that is used to emit light.

The ultra-fluorescent organic light-emitting device can be manufactured by mixing a trace amount of a fluorescent material in the delayed fluorescent light-emitting layer, and such a device can transfer high-efficiency energy obtained through inverse intersystem transition of the delayed fluorescent compound to the fluorescent material. Since the final light emission occurs in the fluorescent dopant compound, high efficiency obtained from delayed fluorescence and high color purity can be realized.

In order to improve the energy transfer efficiency of such a superfluorescent device, it is advantageous as the overlap region between the absorption spectrum of the fluorescent dopant compound and the emission spectrum of the delayed fluorescent compound is wide. Therefore, it is important to have a narrow Stokes shift value in the case of a fluorescent dopant when manufacturing a hyperfluorescent device, and it may be advantageous to select the emission wavelength of delayed fluorescence to be located at the peak absorption spectrum of the fluorescent dopant.

The delayed fluorescent compound represented by Formula 1 has a wide overlapping region with the fluorescent compound represented by Formula 5 or 6 due to the short-wavelength shifted deep blue light emission wavelength, thereby realizing excellent superfluorescence properties.

In one example, the light emitting layer including the delayed fluorescent compound represented by Formula 1 and the fluorescent compound represented by Formula 5 or Formula 6 may further include a host compound. As described above, the organic light emitting device including the light emitting layer including all of the host compound, the delayed fluorescent compound, and the fluorescent compound may be an ultra-fluorescent organic light emitting device. The delayed fluorescent compound acts as a kind of host to form excitons, and these excitons emit light through the fluorescent compound to realize superfluorescence properties.

The fluorescent dopant fluorescent compound may be represented by any one of the following Chemical Formulas F-1 to F-51:

.

.

The compounds F-1 to F-51, which are examples of compounds represented by Formula 5 or Formula 6, are fluorescent dopant compounds based on a DABNA structure or a pyrene structure including a BN structure, and use the delayed fluorescent compound as a host. It can be used as a fluorescence dopant of a delayed fluorescence photosensitive superfluorescence organic light emitting device. For example, when at least one delayed fluorescent compound among the compounds T-1 to T-179 is used as a host and at least one of the compounds F-1 to F-51 is included as a fluorescent dopant, the luminescent properties will be significantly improved. can

In one example, the first electrode is an anode, the second electrode is a cathode, and the functional layer is interposed between the first electrode and the light emitting layer, and at least one of a hole injection layer, a hole transport layer, and an electron blocking layer. hole transport area including; and an electron transport region interposed between the light emitting layer and the second electrode and including at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

A substrate may be additionally disposed below the first electrode or above the second electrode. As the substrate, a substrate used in a general organic light emitting device may be used, and a glass substrate or a transparent plastic substrate excellent in mechanical strength, thermal stability, transparency, surface smoothness, handling easiness and waterproofness may be used.

The first electrode may be a reflective electrode, a transflective electrode, or a transmissive electrode. The first electrode may be formed, for example, on a substrate by a deposition method or a sputtering method of a material for the first electrode. The material for the first electrode may be selected from materials having a high work function to facilitate hole injection. Examples of the material for the first electrode include indium tin oxide (ITO), indium zinc oxide (IZO), and tin oxide. (SnO ₂ ), zinc oxide (ZnO), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg- Ag) and the like can be used.

The hole injection layer may be formed on the first electrode by using various methods such as a vacuum deposition method, a spin coating method, a casting method, a LB method, and the like. In the case of forming the hole injection layer by the vacuum deposition method, the deposition conditions vary depending on the compound used as the hole injection layer material, the structure and thermal characteristics of the target hole injection layer, etc., but, for example, the deposition temperature is about 100 to about 500℃, vacuum about 10 ^-8 to about 10 ^-3 torr, the deposition rate may be selected from about 0.01 to about 100 Å/sec, but is not limited thereto.

In the case of forming the hole injection layer by the spin coating method, the coating conditions are different depending on the compound used as the hole injection layer material, the desired structure and thermal properties of the hole injection layer, but coating at about 2,000 rpm to about 5,000 rpm The rate and the heat treatment temperature for removing the solvent after coating may be selected from a temperature range of about 80° C. to 200° C., but is not limited thereto.

The hole transport layer and the electron blocking layer forming conditions may refer to the hole injection layer forming conditions.

Each layer may have a thickness of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å.

When the light emitting layer includes a host compound and a delayed fluorescent compound, the content of the delayed fluorescent compound as a dopant may be generally selected from about 0.01 to about 45 parts by weight based on about 100 parts by weight of the host compound, but is limited thereto. not.

In addition, when the light emitting layer has hyperfluorescence emission characteristics, 0.01 to 45 parts by weight of the delayed fluorescent compound and the fluorescent dopant compound may be included based on 100 parts by weight of the host compound, but is not limited thereto.

Hereinafter, embodiments of the present invention will be described in more detail. However, the following experimental results describe only representative experimental results among the above examples, and the scope and content of the present invention cannot be construed as being reduced or limited by the examples. Each effect of the various embodiments of the present invention not explicitly presented below will be specifically described in the corresponding section.

Example 1: Synthesis of compound T-11

After stirring a mixture of 2,5-dibromo-1,3-difluorobenzene (15 g, 55.17 mmol) and K ₂ CO ₃ (15.3 g, 110.70 mmol) in dimethylsulfoxide (DMSO) for 15 minutes, p -Cresol (17.9 g, 165.50 mmol) was added and stirred at 100° C. for 24 hours. The reaction mixture was diluted with toluene, extracted with water, dried over anhydrous magnesium sulfate, filtered over silica gel, and concentrated. It was diluted with ethanol, stirred at room temperature for 20 minutes, and filtered. Intermediate 1 (21 g, 85%) as a white solid was obtained under vacuum at 50°C.

The synthesis process of Intermediate 1 is briefly summarized in Scheme 1 below.

[Scheme 1]

A mixture of Intermediate 1 (9 g, 20.082 mmol) dissolved in t-butylbenzene (100 ml) was substituted with argon gas for 15 minutes and then cooled to 0°C. After slowly adding n-butyllithium (13.7 ml, 22.09 mmol) dissolved in hexane, the mixture was stirred at room temperature for 2 hours. Borontribromide (2.35 ml, 24.09 mmol) was added at -30°C. The mixture was stirred at room temperature for 20 minutes and stirred at 50° C. for 1 hour. After cooling to 0° C., DIPEA (6.5 ml, 40.165 mmol) was slowly added. The reaction was stirred at 120° C. for 20 hours and then cooled to room temperature. The reaction was filtered with toluene and Florisil, and concentrated. The residue was purified by column chromatography to give intermediate 2 (3.45 g, 46%).

The synthesis process of Intermediate 2 is briefly summarized in Scheme 2 below.

[Scheme 2]

5-phenyl-5,12-dihydroindole[3,2-a]carbazole (93 mg, 0.2784 mmol), intermediate 2 (100 mg, 0.2652 mmol) and shodium t-butyloxide (51 mg, 0.5304 mmol) To the toluene mixture of tert-t-butylphosphine/HBF4 (6.15 mg, 0.0212 mmol) was added, followed by stirring at 80° C. for 15 minutes. After substitution with nitrogen, Pd ₂ (dba) ₃ (5.17 mg, 0.053 mmol) was added, and the mixture was stirred at 120° C. for 18 hours. The reaction mixture was cooled to room temperature, filtered through Florisil, and concentrated. The residue was recrystallized from dichloromethane and methanol to give compound T-11 (72 mg, 42%).

The synthesis process of compound T-11 is briefly summarized in Scheme 3 below.

[Scheme 3]

Example 2: Synthesis of compound T-16

To a mixture of 5-phenyl-5,12-dihydroindole[3,2-a]carbazole (4 g, 12.033 mmol) in dimethylformamide (DMF) was added NBS (2.25 g 12.634 mmol) and nitrogen After substitution with , the mixture was stirred at room temperature overnight. The mixture was poured into water and extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated to obtain a compound (4.9 g, 98%). Synthesis (6 g), 9-phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolanyl)-9H-carbazole (5.93 g, 16.04 mmol) and K ₂ CO ₃ (6.05 g, 43.734 mmol) was dissolved in tetrahydrofuran, the mixture was substituted with argon gas for 15 minutes, and Pd(PPh ₃ ) ₄ (0.834 g, 0.73 mmol) was added thereto. After refluxing for 18 hours, the reaction mixture was cooled to room temperature and extracted with ethyl acetate (EA) and water. The organic layer was separated, dried over anhydrous magnesium sulfate, filtered, and concentrated. The residue was purified by column chromatography to give a white solid intermediate 3 (3.9 g, 47%).

The synthesis process of Intermediate 3 is briefly summarized in Scheme 4 below.

[Scheme 4]

Intermediate 3 (160 mg, 0.2748 mmol), Intermediate 2 (100 mg, 0.2652 mmol), sodium t-butyloxide (51 mg, 0.5304 mmol) in a toluene mixture of t-butylphosphine/HBF4 (6.15 mg, 0.0212 mmol) After addition, the mixture was stirred at 80 °C for 15 minutes. After replacing with nitrogen, Pd ₂ (dba) ₃ (5.1 mg, 0.0053 mmol) was added. After stirring at 120° C. for 18 hours, the reaction mixture was cooled to room temperature. The reaction product was filtered through Florisil, concentrated, and the residue was recrystallized from dichloromethane and methanol. The obtained solid was washed with heated toluene to obtain a yellow solid compound T-16 (73 mg, 32%).

The synthesis process of compound T-16 is briefly summarized in Scheme 5 below.

[Scheme 5]

Example 3: Synthesis of compound T-26

Compound T-26 (50%) was obtained in the same manner as in Example 2.

The synthesis process of compound T-26 is briefly summarized in Scheme 6 below.

[Scheme 6]

Example 4: Synthesis of compound T-71

Intermediate 4 (35%) was obtained in the same manner as in Example 1.

The synthesis process of Intermediate 4 is briefly summarized in Scheme 7 below.

[Scheme 7]

Compound T-71 (52%) was obtained in the same manner as in Example 2.

The synthesis process of compound T-71 is briefly summarized in Scheme 8 below.

[Scheme 8]

Example 5: Synthesis of compound T-96

Intermediate 5 (23%) was obtained in the same manner as in the synthesis of Intermediate 2 of Example 1, except that 4-(triphenylsilyl)phenol was used instead of p-cresol.

The synthesis process of Intermediate 5 is briefly summarized in Scheme 9 below.

[Scheme 9]

Compound T-96 (32%) was obtained in the same manner as in Example 2.

The synthesis process of compound T-96 is briefly summarized in Scheme 10 below.

[Scheme 10]

Example 6: Synthesis of compound T-114

Intermediate 6 (34%) was obtained in the same manner as in the synthesis of Intermediate 2 of Example 1, except that benzofuran 7-ol was used instead of p-cresol.

The synthesis process of Intermediate 6 is briefly summarized in Scheme 11 below.

[Scheme 11]

Compound T-114 (48%) was obtained in the same manner as in Example 2.

The synthesis process of compound T-114 is briefly summarized in Scheme 12 below.

[Scheme 12]

Experimental Example 1

Using the simulation program shrodinger 2019-3, calculate the BDE (bond dissociation energy) of the neutral, anion, and cation states of the acceptor substituted with a t-butyl group or a methyl group, respectively, in the table below. 1 is shown.

Referring to Table 1, it can be seen that when the t-butyl group is substituted for the electron acceptor, the BDE in the cation and anion states of the carbon bond at the terminal decreases. On the other hand, when the methyl group is substituted for the electron acceptor, it can be confirmed that the BDE in both the cation and anion states is maintained at a high state. A low BDE may accelerate material degradation and cause device lifetime degradation.

Experimental Example 2

The physical properties of the compounds T-11, T-16, T-26 and T-71 prepared in the above Examples were evaluated. The measured physical properties were a UV-Vis absorption spectrum and a room temperature photoluminescence spectrum, and the UV-Vis absorption spectrum was measured by diluting it in toluene solvent to a concentration of 10x ^-4 M using JASCO V-750. Room temperature photoluminescence spectra were measured using the JASCO-FP 8500 equipment under the same conditions. The absolute photoluminescence quantum yield (PLQY) value was measured using an integrating sphere built into the JASCO-FP 8500 equipment after fabricating a thin film by doping 20 wt% of the compound in DBFPO. TRPL (Time-Resolved Photoluminescence) was measured by diluting to a concentration of 10x ^-4 M in dichloromethane solvent using a Hamamatsu C11367 equipment. The measurement results are shown in Table 2 and FIGS. 1 to 3 .

division Example 1 Example 2 Example 3 Example 4 compound compound T-11 compound T-16 compound T-26 compound T-71 Maximum emission spectrum 437 nm 455 nm 460 nm 451 nm Singlet-triplet energy 0.25 eV 0.17 eV 0.10 eV 0.12 eV PLQY 0.91 0.89 0.95 0.95 triplet exciton lifetime 5.50 μs 6.50 μs 0.70 μs 0.71 μs

ITO organic substrate was cut into 50mm x 50mm x 0.7mm size and washed for 10 minutes each using acetone, isopropyl alcohol and distilled water, then irradiated with ultraviolet rays for 10 minutes and cleaned by exposure to ozone and then placed in a vacuum deposition device. The ITO glass substrate was mounted.

HATCN (7 nm) / NPB (50 nm) / PCZAC (10 nm) / mCBP-CN (host) and TDBA-DI, DBA-DI, compound T-26 or compound T-71 (dopant) on the ITO glass substrate 20 wt% (25 nm) / DDBFT (5 nm) / ETL-1 (25 nm) / LiF (1.5 nm) / Al (100 nm) was laminated in the order to prepare an organic light emitting device. The device measurement results are shown in Table 3 and FIGS. 4 to 5 .

division Comparative Example 1 Comparative Example 2 Example 3 Example 4 dopant compound TDBA-DI DBA-DI compound T-26 compound T-71 Max EQE (%) 23.4% 24.6% 20.1% 21.6% Maximum electroluminescence wavelength (nm) 479 nm 490 nm 483 nm 471 nm CIE coordinates (0.14, 0.26) (0.16, 0.41) (0.16, 0.33) (0.14, 0.23) LT80 life 8 hours 37 hours 10 hours 12 hours

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

Claims (6)

A delayed fluorescence compound represented by the following formula (1):
[Formula 1]

In Formula 1, D ₁ is represented by Formulas 2 to 4,
[Formula 2]

[Formula 3]

[Formula 4]

In the above formula,
A ₁ to A ₇ are each independently a substituted or unsubstituted C ₅ ~ C ₆₀ carbocyclic group, a substituted or unsubstituted C ₂ ~ C ₆₀ heterocyclic group, C ₆ ~ C ₆₀ aryl group, and C ₅ ~ C ₆₀ A ring structure selected from a heteroaryl group,
R ₁ To R ₆ are each independently hydrogen, deuterium, a straight-chain or branched alkyl group substituted with deuterium, a substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group, a substituted or unsubstituted C ₃ ~ C ₆₀ cycloalkyl group, A substituted or unsubstituted C ₃ ~C ₆₀ silyl group, a substituted or unsubstituted C ₂ ~C ₆₀ heterocyclic group, a substituted or unsubstituted C ₆ ~C ₆₀ aryl group, a substituted or unsubstituted C ₅ ~C It is one selected from ₆₀ heteroaryl groups, or a pentagonal heteroaryl ring structure including one of O, S, and NR ₁₄ formed by bonding two adjacent substituents,
Y ₁ To Y ₂ are each independently hydrogen or form a ring by bonding to each other,
Y ₃ to Y ₅ are each independently one selected from O, S, NR ₁₅ and C-(R ₁₆ ) ₂ ,
R ₇ To R ₁₃ are each independently hydrogen, deuterium, a nitrile group, a halogen group, a substituted or unsubstituted C ₁ to C ₆₀ alkyl group, a substituted or unsubstituted C ₃ to C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₁ ~ C ₆₀ alkoxy group, substituted or unsubstituted C ₃ ~ C ₆₀ silyl group, substituted or unsubstituted C ₆ ~ C ₆₀ aryl group, and substituted or unsubstituted C ₆ ~ C ₆₀ heteroaryl group, substituted or It is selected from an unsubstituted C ₆ -C ₆₀ diarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ diheteroarylamino group, a substituted or unsubstituted C ₆ -C ₆₀ arylheteroarylamino group,
R ₁₄ to R ₁₆ are each hydrogen, deuterium, a substituted or unsubstituted C ₁ -C ₆₀ alkyl group, a substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₆ -C ₆₀ aryl group, and It is selected from a substituted or unsubstituted C ₆ ~ C ₆₀ heteroaryl group. According to claim 1,
A delayed fluorescence compound represented by any one of the following formulas T-1 to T-179:

. a first electrode;
a second electrode provided to face the first electrode; and
Including; at least one functional layer interposed between the first electrode and the second electrode;
At least one of the functional layers is a light emitting layer comprising at least one delayed fluorescent compound according to any one of claims 1 to 2, an organic light emitting device. 4. The method of claim 3,
The light emitting layer further comprises a fluorescent dopant compound represented by the following Chemical Formula 5 or Chemical Formula 6, an organic light emitting device:
[Formula 5]

[Formula 6]

In the above formula,
R ₁₇ to R ₂₅ are each independently hydrogen, deuterium, halogen, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C ₁ ~ C ₆₀ alkyl group , substituted or unsubstituted C ₂ ~ C ₆₀ alkenyl group, substituted or unsubstituted C ₂ ~ C ₆₀ alkynyl group, substituted or unsubstituted C ₁ ~ C ₆₀ alkoxy group, substituted or unsubstituted C ₃ ~ C ₁₀ Cycloalkyl group, substituted or unsubstituted C ₂ -C ₁₀ heterocycloalkyl group, substituted or unsubstituted C ₃ -C ₁₀ cycloalkenyl group, substituted or unsubstituted C ₂ -C ₁₀ heterocycloalkenyl group, substituted or unsubstituted C ₆ ~ C ₆₀ aryl group, substituted or unsubstituted C ₆ ~ C ₆₀ aryloxy group, substituted or unsubstituted C ₆ ~ C ₆₀ arylthio group, substituted or unsubstituted C ₁ ~ C ₆₀ heteroaryl group , a substituted or unsubstituted C ₁ ~ C ₆₀ heteroaryloxy group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group,
Y ₆ To Y ₉ are each independently hydrogen, or combine with each other to form a ring. 5. The method of claim 4,
An organic light emitting device, wherein the fluorescent dopant fluorescent compound is represented by any one of the following Chemical Formulas F-1 to F-51:

. 5. The method of claim 3 or 4,
the first electrode is an anode, the second electrode is a cathode,
The functional layer is
a hole transport region interposed between the first electrode and the light emitting layer and including at least one of a hole injection layer, a hole transport layer, and an electron blocking layer; and
and an electron transport region interposed between the light emitting layer and the second electrode, the electron transport region including at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

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