KR20160056783A - Delayed Fluorescence compound, and Organic light emitting diode device and Display device including the same - Google Patents

Abstract

The present invention provides a delayed fluorescent compound having a structure of molecular formula, in which a first electron donor moiety which is acridine and a second electron donor moiety selected from carbazole, triphenylamine, acridine, and a derivative thereof are combined with an electron acceptor moiety selected from substituted or non-substituted phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline, and a derivative thereof. A low quantum efficiency problem of a fluorescent material is resolved.

Description

TECHNICAL FIELD [0001] The present invention relates to a retardation fluorescent compound, an organic light emitting diode (OLED)

The present invention relates to a luminescent material. More particularly, the present invention relates to a retardation fluorescent compound having improved luminous efficiency by intramolecular charge transfer, an organic light emitting diode device including the same, and a display device.

Recently, the demand for a flat display device having a small space occupancy has been increased due to the enlargement of a display device. The technology of an organic light emitting diode device, which is also called an organic light emitting diode (OLED) .

An organic light-emitting diode device is a device that emits light when electrons and holes are injected from a cathode and an anode into a light emitting material layer formed between an electron injection electrode (cathode) and a hole injection electrode (anode) . The device can be formed not only on a flexible transparent substrate such as a plastic but also can be driven at a low voltage (10 V or less), has relatively low power consumption, and is excellent in color.

The organic light emitting diode device includes a first electrode that is an anode, a second electrode that faces the first electrode, and an organic light emitting layer that is disposed between the first electrode and the second electrode.

In order to improve the luminous efficiency, the organic light emitting layer may include a hole injection layer (HIL), a hole transporting layer (HTL), an emitting material layer (EML) , An electron transporting layer (ETL), and an electron injection layer (EIL).

The holes are moved from the first electrode as the anode to the light emitting material layer through the hole injecting layer and the hole transporting layer and electrons are moved from the second electrode as the cathode to the light emitting material layer through the electron injecting layer and the electron transporting layer.

The holes and electrons transferred to the light emitting material layer combine with each other to form an exciton, which excites into an unstable energy state, and returns to a stable energy state to emit light.

The external quantum efficiency (eta _ext ) of the luminescent material used in the luminescent material layer can be obtained by the following equation.

η _ext = η _int × г × Φ × η _{out - coupling}

(Η _int : internal quantum efficiency, Φ: radiative quantum efficiency, η _{out - coupling} : out coupling efficiency)

The charge balance factor (г) is the balance between hole and electron forming the exciton, and generally has a value of 1 assuming 100% 1: 1 matching. Radiative quantum efficiency (Φ) is a value related to the luminescence efficiency of a practical luminescent material, and depends on the fluorescence quantum efficiency of the dopant in the host-dopant system.

The internal quantum efficiency (eta _int ) has a limiting value of 0.25 at maximum for the fluorescent material, at a rate at which the generated excitons are converted to the form of light. When excitons are formed by the combination of holes and electrons, a singlet exciton and a triplet exciton are generated at a ratio of 1: 3 according to the arrangement of the spin. However, in the fluorescent material, only the single-exciton participates in the luminescence and the remaining 75% of the triplet exciton does not participate in the luminescence.

Out coupling efficiency (η _{out - coupling} ) is the ratio of light extracted to the outside of the emitted light. In general, when an isotropic molecule is thermally deposited to form a thin film, the individual luminescent molecules do not have a certain directionality and exist in a disordered state. The out coupling efficiency in this random orientation state is generally assumed to be 0.2.

Therefore, the maximum luminous efficiency of the organic light emitting diode device using the fluorescent material is about 5% or less.

In order to overcome the low efficiency problem of the fluorescent material as described above, a phosphorescent material having a light emitting mechanism that converts both singlet excitons and triplet excitons to light has been developed.

In the case of red and green phosphors having high luminous efficiency have been developed, phosphors that satisfy the required luminous efficiency and reliability in the case of blue have not been developed.

Therefore, in a fluorescent material satisfying reliability, development of a material capable of increasing the luminous efficiency by increasing the quantum efficiency is required.

The present invention aims at solving the problem of low quantum efficiency of fluorescent materials.

In order to solve the above problems, the present invention has a molecular formula in which each of the first electron donating moiety and the second moiety is an acridine and is connected to the electron accepting moiety.

The second electron donor moiety may be selected from carbazole, triphenylamine, acridine, and derivatives thereof, and the electron acceptor moiety may be selected from substituted or unsubstituted triazine, dibenzothiophenesulfone, diphenylsulfone, Thienopyrimidine, thienopyridine, quinoxaline, and derivatives thereof.

That is, the retarding fluorescent compound of the present invention is represented by the following formula: wherein X is selected from substituted or unsubstituted triazine, dibenzothiophenesulfone, diphenylsulfone, thienopyrazine, quinoxaline, and derivatives thereof, Y may be selected from carbazole, triphenylamine, acridine, and derivatives thereof.

In addition, the present invention provides an organic light emitting diode device and a display device, wherein the organic light emitting layer includes the above retarded fluorescent compound.

The retarded fluorescent compound of the present invention has a structure in which the first and second electron donor moieties are bonded to an electron acceptor moiety so that the charge can easily migrate in the molecule and the light emitting efficiency is improved . Particularly, in the retarded fluorescent compound of the present invention, since the triplet exciton is used for luminescence, the luminescent efficiency of the retarded fluorescent compound is improved.

Further, acridine having a hexagonal structure is used as an electron donor moiety, so that the steric hindrance with the electron acceptor moiety becomes large, and the angle between the acridine electron donor moiety and the electron acceptor moiety increases. Therefore, the conjugation formation between the electron donor moiety and the electron acceptor moiety is restricted, and the separation between the HOMO and the LUMO occurs smoothly, thereby further enhancing the luminous efficiency.

In addition, a dipole is formed from one or more electron donor moieties to electron acceptor moieties to increase the dipole moment inside the molecule, thereby further enhancing the luminous efficiency.

In addition, the first and second electron donor moieties and the electron acceptor moiety are bonded in the molecule and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) The field-activated delayed fluorescence complex is formed and the luminous efficiency of the retarded fluorescent compound is further improved.

Accordingly, the luminous efficiency of the organic light emitting diode device and the display device including the retarded fluorescent compound of the present invention is also improved.

1 is a view for explaining an emission mechanism of a retardation fluorescent compound according to an embodiment of the present invention.
2A and 2B are diagrams for explaining the molecular structure of a compound containing a carbazole electron donating moiety.
FIGS. 3A and 3B are diagrams illustrating the molecular structure of a compound containing an acridine electron donating moiety. FIG.
4A to 4C are graphs showing delayed fluorescence characteristics of a retarded fluorescent compound according to an embodiment of the present invention.
5 is a schematic cross-sectional view of an organic light emitting diode device according to an embodiment of the present invention.

The present invention relates to a process for preparing an electron donor moiety comprising a first electron donor moiety which is an acridine and a second electron donor moiety which is selected from carbazole, triphenylamine, acridine and derivatives thereof An electron donor selected from substituted or unsubstituted phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline, and derivatives thereof an electron acceptor moiety having a molecular formula of a structure to be bonded.

In another aspect, the present invention provides a retarded fluorescent compound represented by the following formula (1), wherein X is selected from the following formula (2) and Y is selected from the following formula (3).

[Chemical Formula 1]

(2)

(3)

(Wherein R is hydrogen or phenyl).

The delayed minerals of the present invention are characterized by being any of the following compounds.

In the delayed minerals of the present invention, the difference between the singlet energy and the triplet energy of the delayed fluorescent compound may be 0.3 eV or less.

In another aspect, the present invention provides an organic electroluminescent device comprising a first electrode, a second electrode facing the first electrode, and an organic light emitting layer positioned between the first and second electrodes, A second electron donor moiety selected from the group consisting of carbazole, triphenylamine, acridine, and derivatives thereof, wherein the second electron donor moiety is a substituted or unsubstituted triazine is coupled to an electron acceptor moiety selected from phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline, and derivatives thereof. An organic light emitting diode device including a retardation fluorescent compound having a molecular formula of the structure.

According to another aspect of the present invention, there is provided a light emitting device comprising a first electrode, a second electrode facing the first electrode, and an organic light emitting layer positioned between the first and second electrodes, , Y is selected from the following formula (2), and X is selected from the following formula (3).

[Chemical Formula 1]

(2)

(3)

(Wherein R is hydrogen or phenyl).

In the organic light-emitting diode device of the present invention, the retarded fluorescent compound may be any one of the following compounds.

In the organic light emitting diode device of the present invention, the difference between the singlet energy and the triplet energy of the delayed fluorescent compound may be 0.3 eV or less.

In the organic light emitting diode device of the present invention, the delayed fluorescent compound may be used as a dopant, and the organic light emitting layer may further include a host.

In the organic light emitting diode device of the present invention, the difference between the highest level occupied molecular orbital level (HOMO _Host ) of the _host and the highest level occupied molecular orbital level (HOMO _Dopant ) of the _dopant (| HOMO _Host- HOMO _Dopant | the lowest level unoccupied molecular orbital level (LUMO _Host) and the lowest unoccupied molecular orbital level level (LUMO _dopant) of the dopant, the difference (| LUMO _{Host dopant} -LUMO |) may be equal to or less than 0.5eV.

In the organic light emitting diode device of the present invention, the delayed fluorescent compound may be used as a host, and the organic light emitting layer may further include a dopant.

In the organic light emitting diode device of the present invention, the delayed fluorescent compound is used as a first dopant, and the organic light emitting layer further comprises a host and a second dopant, wherein the first triplet energy of the first dopant is May be less than the second triplet energy and greater than the third triplet energy of the second dopant.

In the organic light emitting diode device of the present invention, the organic light emitting layer may include a hole injecting layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, and an electron injecting layer, wherein the hole injecting layer, At least one of the electron transport layer and the electron injection layer may include the retarded fluorescent compound.

The present invention also provides a display device including the above-described organic light emitting diode positioned on a substrate, an encapsulation film covering the organic light emitting diode, and a cover window on the encapsulation film.

Hereinafter, a structure of a retarded fluorescent compound according to an embodiment of the present invention, a synthesis example thereof, and an organic light emitting diode device using the same will be described.

The retarded fluorescent compound according to an embodiment of the present invention includes a first electron donor moiety that is acridine and a second electron donor moiety that is the same as or different from the first electron donating moiety, and has a molecular formula of a structure which is bonded to an electron acceptor moiety.

[Chemical Formula 1]

In the above formula (1), the electron acceptor moiety X may be a substituted or unsubstituted phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline quinoxaline and derivatives thereof. For example, the electron acceptor moiety X may be selected from the materials shown in Formula 2 below.

(2)

In Formula 2, R may be hydrogen or phenyl.

In the above Formula 1, the second electron donating moiety Y may be selected from hole injectable materials such as carbazole, triphenylamine, acridine, and derivatives thereof. do. And Y, which is the second electron donating moiety, may be selected from the substances represented by the following formula (3).

(3)

Such a retarded fluorescent compound contains both the first and second electron donor moieties and electron acceptor moieties, so that the charge can easily move in the molecule and the luminous efficiency is improved. In addition, a dipole is formed from the first and second electron donor moieties to the electron acceptor moiety to increase the dipole moment in the molecule, thereby further enhancing the luminous efficiency.

Particularly, in the retarded fluorescent compound of the present invention, since the triplet exciton is used for luminescence, the luminescent efficiency of the retarded fluorescent compound is improved.

Further, acridine having a hexagonal structure is used as an electron donor moiety, so that the steric hindrance with the electron acceptor moiety becomes large, and the angle between the acridine electron donor moiety and the electron acceptor moiety increases. Therefore, the conjugation formation between the electron donor moiety and the electron acceptor moiety is restricted, and the separation between the HOMO and the LUMO occurs smoothly, thereby further enhancing the luminous efficiency.

In addition, the first and second electron donor moieties and the electron acceptor moiety are bonded in the molecule and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) The electric field activating complex is formed and the luminous efficiency of the retarded fluorescent compound is further improved.

1, which is a drawing for explaining the luminescent mechanism of a retarding fluorescent compound according to an embodiment of the present invention, in the retarding fluorescent compound of the present invention, both singlet excitons and triplet excitons participate in luminescence, thereby improving quantum efficiency do.

That is, the delayed fluorescent compound of the present invention activates the triplet exciton by the electric field so that the triplet exciton and the singlet exciton move to the intermediate state (I ₁ ) and the ground state (S ₀ ) And emits light. In other words, the transition from singlet state (S ₁ ) and triplet state (T ₁ ) to intermediate state (I ₁ ) occurs (S ₁ -> I ₁ <-T ₁ ), and both singlet excitons and triplet excitons The light emitting efficiency is improved. This is referred to as FADF (filed activated delayed fluorescence) compound.

Conventional fluorescent materials are unable to switch between single-state and triplet states because HOMO and LUMO are distributed throughout the molecule. (selection rule)

However, in the FADF compound as in the present invention, the interactions between HOMO and LUMO are small because the overlapping of HOMO and LUMO in the molecule is small. Therefore, the change in the spin state of the electrons does not affect other electrons, and a new charge transfer band that does not follow the selection rule is formed.

Also, since the first and second electron acceptor moieties and the electron donor moiety are spaced apart in the molecule, the dipole moment in the molecule is present in a polarized form. In the state where the dipole moment is polarized, the interaction between HOMO and LUMO becomes small and the selection rule may not be followed. Therefore, in the FADF compound, a transition to the triplet state (T ₁₎ and the intermediate states (I ₁₎ in a singlet state (S ₁₎ becomes possible, triplet exciton is involved in light emission.

When the organic light emitting diode device is driven, 25% of singlet state excitons (S ₁ ) excitons and 75% of triplet excitons (T ₁ ) excitons cause an interstage transition to an intermediate state (I ₁ ) ₀ ), the internal quantum efficiency is theoretically 100%.

For example, the delayed fluorescent compound of formula (1) may be any of the compounds of formula (4).

[Chemical Formula 4]

The delayed fluorescent compound of the present invention includes acridine as the first electron donating moiety so that the steric hindrance between the first electron donating moiety and the electron accepting moiety becomes large and the first electron donating moiety and the electron accepting moiety The back angle increases.

FIGS. 2A and 2B are diagrams for explaining the molecular structure of a compound containing a carbazole electron donating moiety, and FIGS. 3A and 3B are diagrams for explaining the molecular structure of a compound containing an acridine electron donating moiety FIG.

Referring to Figs. 2A and 2B, when a carbazole is used as an electron donor moiety, the dihedral angle between the pole donut moiety and the electron acceptor moiety is about 44 degrees.

3A and 3B, when acridine is used as an electron donor moiety, the dihedral angle between the pole donut moiety and the electron acceptor moiety is about 89 degrees. That is, when acridine is included as the electron donor moiety, the back angle between the electron donor moiety and the electron acceptor moiety increases, and the conjugation formation between the electron donor moiety and the electron acceptor moiety is restricted. Therefore, in the compound containing an acridine electron donor moiety, the separation between HOMO and LUMO occurs smoothly and the luminous efficiency is further enhanced as compared with the compound containing carbazole.

Hereinafter, examples of synthesis of a retarded fluorescent compound according to an embodiment of the present invention will be described.

- Synthesis Example -

1. Synthesis of Compound 1

(1) Synthesis of compound a

[Reaction Scheme 1-1]

2,8-Dibromodibenzothiophene (14.6 mmol) and acetic acid solvent were stirred under a nitrogen atmosphere. Hydrogen peroxide (64.8 mmol) was added, and the mixture was stirred at room temperature for about 30 minutes and refluxed for at least 12 hours. After completion of the reaction, 50 ml of distilled water was added and the mixture was stirred and washed. After filtration, the solid was stirred with an excess amount of hydrogen peroxide and then washed for 30 minutes to one hour. Washed with distilled water, filtered and dried to obtain a white solid compound a. (Yield: 90%).

(2) Synthesis of compound b

[Reaction Scheme 1-2]

N-phenylanthranilic acid (46.9 mmol) was mixed in a methanol solvent and stirred in a nitrogen atmosphere. After further stirring at 0 ° C for 10 minutes, thionyl chloride (21.2 mmol) was slowly dropped. The mixed solution was stirred at 90 ° C for 12 hours or more. After completion of the reaction, the solvent was removed, and distilled water and ethyl acetate were added to extract. Water was removed from the organic layer extracted with magnesium sulfate, the solvent was removed, and wet-refinement was carried out by column chromatography using hexane and ethyl acetate. A dark yellow liquid state compound b was obtained. (Yield: 81%).

(3) Synthesis of Compound c

[Reaction 1 - 3]

Compound b (38.1 mmol) was stirred in a tetrahydrofuran solvent in a nitrogen atmosphere. Methyl magnesium bromide (4.6 equivalents) was slowly dropped and reacted by stirring at room temperature for 12 hours or longer. After completion of the reaction, distilled water was slowly added thereto and extracted with ethyl acetate. Water was removed from the organic layer extracted with magnesium sulfate and the solvent was removed. The product was subjected to wet purification through column chromatography using hexane and ethyl acetate to obtain a yellow liquid compound c. (Yield: 87%).

(4) Synthesis of compound d

[Reaction Scheme 1-4]

Compound c (33.1 mmol) was added to an excess of phosphoric acid (160 ml) and stirred at room temperature. After stirring for more than 16 hours, 200 ~ 250 ml of distilled water was slowly added. After stirring for 0.5 to 1 hour, the precipitated solid was filtered. The filtered solid was extracted with an aqueous solution of sodium hydroxide and dichloromethane. Water was removed from the organic layer extracted with magnesium sulfate and the organic solvent was removed to obtain a white solid compound d. (Yield: 69%).

(5) Synthesis of Compound 1

[Reaction Scheme 1-5]

Compound d (0.3 mol) and the compound a (0.15 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with toluene solvent under a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and Compound 1 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 81%).

2. Synthesis of Compound 2

[Reaction Scheme 2]

Compound d (0.3 mol) and 4-bromophenyl sulfone (0.15 mol), Pd (OAc ) 2 (6.11 mmol) and _{P (t-Bu) 3 (} 50 wt%, 15.28 mmol), NaOt-Bu (sodium tert -butoxide, 0.61 mol) was stirred with toluene solvent under a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and Compound 2 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 80%).

3. Synthesis of Compound 3

(1) Synthesis of Compound e

[Reaction Scheme 3-1]

A nitrogen atmosphere was established in the flask with the light shielding, and bromobenzene (0.9 equivalent) was dissolved in tetrahydrofuran at -78 ° C. The n-butyllithium was slowly dropped at low temperature. 2,4,6-trichloro-1,3,5-triazine dissolved in tetrahydrofuran was added dropwise in a nitrogen atmosphere using a cannula and stirred for 8 hours. After completion of the reaction, Compound e was obtained through purification. (Yield: 45%).

(2) Synthesis of Compound 3

[Reaction Scheme 3-2]

The catalyst Pd (dba) ₂ (5% mol) and P (t-Bu) ₃ (4% mol) were added to toluene solvent in a nitrogen atmosphere and stirred for about 15 minutes. Compound e (33.8 mmol), compound d (16.9 mmol) and NaOt-Bu (60.6 mmol) were further added thereto, followed by stirring at 90 ° C for 5 hours. After the completion of the reaction, the organic solvent was removed by filtration using celite. The resulting solid was purified by column chromatography using hexane and dichloromethane, and recrystallized from hexane. Compound 3 was obtained through wet purification. (Yield: 59%)

4. Synthesis of Compound 4

[Reaction Scheme 4]

Compound d (0.3 mol) and 5,8-dibromo-quinoxaline (0.15 mol), Pd (OAc ) 2 (6.11 mmol) and _{P (t-Bu) 3 (} 50 wt%, 15.28 mmol), NaOt-Bu ( sodium tert-butoxide, 0.61 mol) was stirred with toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and Compound 4 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 79%).

5. Synthesis of Compound 5

(1) Synthesis of compound f

[Reaction Scheme 5-1]

In a nitrogen atmosphere, 3,4-diaminothiophene dihydrochloride (5.52 mmol) was slowly added to the mixture of Na ₂ CO ₃ (5%, 60 ml) and glyoxal (6.1 mmol) for 5 minutes. 15 ml of diluted glyoxal solution at 40% was added. Stir at room temperature for 3 hours and rapidly extracted with ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate, and the organic solvent was removed. (Not heated upon removal of solvent) Compound f was obtained through column chromatography wet column purification using dichloromethane and hexane. (Yield: 70%).

(2) Synthesis of Compound g

[Reaction Scheme 5-2]

Compound f (14.7 mmol) was stirred in a chloroform / acetic acid (1: 1) solvent in a nitrogen atmosphere. The mixture was cooled to 0 ° C and N-bromosuccinimide (NBS, 32.3 mmol) was added thereto. The reaction mixture was stirred at room temperature for 12 hours or longer. After completion of the reaction, distilled water was added by the amount of the reaction solvent and extracted with chloroform. Water was removed from the extracted organic layer using magnesium sulfate, and the remaining organic solvent was removed without heating. The remaining solid was washed with diethyl ether. Compound g was obtained by column chromatography wet column purification using dichloromethane and hexane. (Yield: 75%).

(3) Synthesis of Compound 5

[Reaction Scheme 5-3]

Compound d (0.3 mol) and the compound g (0.15 mol), Pd ( OAc) 2 (6.11 mmol) and _{P (t-Bu) 3 (} 50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 5 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 70%).

6. Synthesis of Compound 6

(1) Synthesis of compound h

[Reaction Scheme 6-1]

It was dissolved in 1,4-dioxane carbazol-solvent in a nitrogen atmosphere, was added CuI and K ₃ PO _4. Compound a (1.1 eq.) And trans-1,2-diaminocyclohexane were further added. And the mixture was refluxed and stirred at 110 ° C for 24 hours. After reaction, the reaction mixture was cooled to room temperature and extracted with ethyl acetate and distilled water. Water was removed from the extracted organic layer using magnesium sulfate and the remaining organic solvent was removed. Compound h was obtained through column chromatography wet purification using ethyl acetate and hexane. (Yield: 58%).

(2) Synthesis of Compound 6

[Reaction Scheme 6-2]

Compound d (0.33 mol) and Compound h (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent is removed and compound 6 can be obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 55%).

7. Synthesis of Compound 7

(1) Synthesis of compound i

[Reaction Scheme 7-1]

It was dissolved in 1,4-dioxane carbazol-solvent in a nitrogen atmosphere, was added CuI and K ₃ PO _4. 4-bromophenylsulfone (1.1 eq.) And trans-1,2-diaminocyclohexane were further added. And the mixture was refluxed and stirred at 110 ° C for 24 hours. After reaction, the reaction mixture was cooled to room temperature and extracted with ethyl acetate and distilled water. Water was removed from the extracted organic layer using magnesium sulfate and the remaining organic solvent was removed. Compound i was obtained by column chromatography wet column purification using ethyl acetate and hexane. (Yield: 60%).

(2) Synthesis of Compound 7

[Reaction Scheme 7-2]

Compound d (0.33 mol) and compound i (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 7 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 65%).

8. Synthesis of Compound 8

(1) Synthesis of compound j

[Reaction Scheme 8-1]

Compound a was dissolved in a toluene solvent in a nitrogen atmosphere, and then 4- (diphenylamino) phenylboronic acid (1.1 equivalent) was added. K ₂ CO ₃ (4.4 eq.) Was dissolved in distilled water and then added to the reaction mixture. After the addition of the tetrahydrofuran solvent, palladium (Pd, 0.05 eq.) Was added. Thereafter, the reaction mixture was refluxed at 80 DEG C and stirred. After completion of the reaction, the reaction mixture was extracted with ethyl acetate, and water was removed from the extracted organic layer using magnesium sulfate. The remaining solvent was removed and purification by column chromatography using dichloromethane and hexane gave compound j. (Yield: 56%)

(2) Synthesis of Compound 8

[Reaction Scheme 8-2]

Compound d (0.33 mol) and compound j (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 8 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 50%).

9. Synthesis of Compound 9

(1) Synthesis of compound k

[Reaction Scheme 9-1]

4-Bromophenylsulfone was dissolved in a toluene solvent in a nitrogen atmosphere, and 4- (diphenylamino) phenylboronic acid (1.1 equivalent) was added. K ₂ CO ₃ (4.4 eq.) Was dissolved in distilled water and then added to the reaction mixture. After the addition of the tetrahydrofuran solvent, palladium (Pd, 0.05 eq.) Was added. Thereafter, the reaction mixture was refluxed at 80 DEG C and stirred. After completion of the reaction, the reaction mixture was extracted with ethyl acetate, and water was removed from the extracted organic layer using magnesium sulfate. The remaining solvent was removed, and compound k was obtained through column chromatography purification using dichloromethane and hexane. (Yield: 55%).

(2) Synthesis of Compound 9

[Reaction Scheme 9-2]

Compound d (0.33 mol) and compound k (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 9 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 45%).

10. Synthesis of Compound 10

(1) Synthesis of compound 1

[Reaction Scheme 10-1]

It was dissolved in 1,4-dioxane carbazol-solvent in a nitrogen atmosphere, was added CuI and K ₃ PO _4. 5,8-dibromoquinoxaline (1.1 eq.) And trans-1,2-diaminocyclohexane were further added. And the mixture was refluxed and stirred at 110 ° C for 24 hours. After the reaction mixture is cooled to room temperature, it is extracted with ethyl acetate and distilled water. Water was removed from the extracted organic layer using magnesium sulfate and the remaining organic solvent was removed. Compound 1 was obtained through column chromatography wet purification using ethyl acetate and hexane. (Yield: 48%).

(2) Synthesis of Compound 10

[Reaction formula 10-2]

Compound d (0.33 mol) and compound l (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 10 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 50%).

11. Synthesis of Compound 11

(1) Synthesis of compound m

[Reaction Scheme 11-1]

In a nitrogen atmosphere, 5,8-dibromoquinoxaline was dissolved in toluene solvent, and 4- (diphenylamino) phenylboronic acid (1.1 equivalent) was added. K ₂ CO ₃ (4.4 eq.) Was dissolved in distilled water and then added to the reaction mixture. After the addition of the tetrahydrofuran solvent, palladium (Pd, 0.05 eq.) Was added. Thereafter, the reaction mixture was refluxed at 80 DEG C and stirred. After completion of the reaction, the reaction mixture was extracted with ethyl acetate, and water was removed from the extracted organic layer using magnesium sulfate. The remaining solvent was removed, and the compound m was obtained through column chromatography purification using dichloromethane and hexane. (Yield: 43%).

(2) Synthesis of Compound 11

[Reaction Scheme 11-2]

Compound d (0.33 mol) and compound m (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 11 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 50%).

12. Synthesis of Compound 12

(1) Synthesis of compound n

[Reaction Scheme 12-1]

It was dissolved in 1,4-dioxane carbazol-solvent in a nitrogen atmosphere, was added CuI and K ₃ PO _4. Compound g (1.1 eq.) And trans-1,2-diaminocyclohexane were further added. And the mixture was refluxed and stirred at 110 ° C for 24 hours. After reaction, the reaction mixture was cooled to room temperature and extracted with ethyl acetate and distilled water. Water was removed from the extracted organic layer using magnesium sulfate and the remaining organic solvent was removed. Compound n was obtained through column chromatography wet purification using ethyl acetate and hexane. (Yield: 45%).

(2) Synthesis of Compound 12

[Reaction Scheme 12-2]

Compound d (0.33 mol) and compound n (0.33 mol), Pd ( OAc) 2 (6.11 mmol), P (t-Bu) 3 (50 wt%, 15.28 mmol), NaOt-Bu (sodium tert-butoxide, 0.61 mol) were stirred with a toluene solvent in a nitrogen atmosphere. And the mixture was refluxed and stirred at 120 ° C for 12 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and extracted with water and ethyl acetate. Water was removed from the extracted organic layer using magnesium sulfate. The remaining organic solvent was removed and compound 12 was obtained by column chromatography wet column purification using hexane and ethyl acetate. (Yield: 49%).

The results of mass spectrometry of the compounds 1 to 12 are shown in Table 1.

The emission characteristics of the compounds 5, 9, and 11 (Com5, Com9, and Com11) were measured under the O ₂ free condition using a Quantarus tau instrument manufactured by Hamamatsu Co. The measurement results are shown in Table 2 and FIGS. 4A to 4C.

As shown in Table 2 and FIGS. 4A to 4C, the delayed fluorescent compounds 5, 9 and 11 (Com5, Com9, Com11) according to the present invention each exhibited delayed fluorescence of tens of nanoseconds (ns).

As described above, the retarded fluorescent compound of the present invention is field activated to convert monophasic state (S ₁ ) excitons and triplet state (T ₁ ) excitons to intermediate states (I ₁ ) .

Such a field activating complex is a monomolecular compound having a first and a second electron donating moiety and an electron accepting moiety at the same time in one molecule, and the transfer of electrons easily occurs in the molecule. The electric field activating complexes may under certain conditions migrate electrons from the electron donor moiety to the electron acceptor moiety, resulting in the separation of charges within the molecule.

The electroluminescent complex to be elected is formed by the external environment, which can be easily confirmed by comparing the absorption wavelength and the emission wavelength in the solution state using various solvents.

In the above equation, Δν is the stock shift value, and νabs and νfl are the wavenumber of the maximum absorption wavelength and the maximum emission wavelength, respectively. H is the Plank? Constant, c is the velocity of light, a is the onsager cavity radius, and? Μ is the difference between the dipole moment of the exited state and the dipole moment of the ground state (Δμ = μ _{e- g} ).

Δf is the value representing the orientational polarizability of the solvent and is expressed by the dielectric constant (ε) and the refractive index (n) of the solvent as shown in the following equation.

The formation of the field activation complex can be confirmed by comparing the absorption wavelength and the emission wavelength in the solution state using various solvents. This is because the degree of polarization (magnitude of the dipole moment) when excited is determined by the surrounding polarity.

The directional polarization degree of the mixed solvent, Δf, can be calculated by calculating the ratio of the polarizability of the pure solvent to the mole fraction, respectively. The presence or absence of the electric field activating complex can be calculated using the above equation (Lippert-Mataga equation) By plotting and plotting a linear relationship.

That is, the electric field activating complex is stabilized according to the directional polarization degree of the solvent, and the emission wavelength shifts to a long wavelength according to the stabilization degree. Therefore, when an electric field activating complex is formed, Δf and Δν form a linear graph. Conversely, when Δf and Δν form a linear graph, the light emitting material is an electric field activating complex.

In the retarded fluorescent compound of the present invention, 25% of the singlet-state excitons and 75% of the triplet-state excitons are excited by an electromagnetic field generated in the external environment, for example, an organic light-emitting diode device, And the quantum efficiency is improved because light is emitted from the intermediate state to the ground state. That is, in the fluorescent material, as well as singlet state excitons, triplet state excitons participate in luminescence, thereby improving the luminous efficiency.

Hereinafter, the performance of the organic light emitting diode using the delayed fluorescent compound of the present invention and the organic light emitting diode using the comparative substance of the formula (5) will be compared.

Device fabrication

The ITO substrate was patterned to have a light emitting area of 3 mm x 3 mm and then cleaned. Next, the substrate was transferred into a vacuum deposition chamber. (N-N'-di (naphthalen-1-yl) -N, N'-dicyclohexylcarbodiimide) on the ITO which is an anode after the base pressure is about 10 ^-6 to 10 ^-7 Torr. diphenyl-benzidine), ii) a hole transport layer (10 nm, mCP (N, N'-Dicarbazolyl-3,5-benzene) phenyl] ether oxide / dopant (6%), iv) an electron transport layer (30 nm, 1,3,5-tri (phenyl-2-benzimidazole) (Al) were successively laminated.

(1) Comparative Example (Ref)

In the above-mentioned device, the compound of Chemical Formula 5 was used as a dopant of the light emitting material layer.

(2) Experimental Example 1 (Ex1)

In the above-mentioned device, Compound 1 was used as a dopant of the light emitting material layer.

(3) Experimental Example 2 (Ex2)

In the above-described device, Compound 2 was used as a dopant of the light emitting material layer.

(4) Experimental Example 3 (Ex3)

In the above-mentioned device, Compound 3 was used as a dopant of the light emitting material layer.

(5) Experimental Example 4 (Ex4)

In the above-described device, Compound 4 was used as a dopant of the light emitting material layer.

(6) Experimental Example 5 (Ex5)

In the above-mentioned device, Compound 5 was used as a dopant of the light emitting material layer.

(7) Experimental Example 6 (Ex6)

In the above-mentioned device, Compound 6 was used as a dopant of the light emitting material layer.

(8) Experimental Example 7 (Ex7)

In the above-mentioned device, the compound 12 was used as a dopant of the light emitting material layer.

[Chemical Formula 5]

As can be seen from Table 3, the organic light emitting diode device using the retarded fluorescent compound of the present invention has improved characteristics in terms of driving voltage, luminous efficiency, and the like.

An embodiment of the organic light emitting diode device including the above retarded fluorescent compound is shown in FIG.

As shown in FIG. 5, the organic light emitting diode device includes a light emitting diode (E) located on a substrate (not shown).

The light emitting diode E includes a first electrode 110 serving as an anode, a second electrode 130 serving as a cathode, and an organic light emitting layer 120 formed between the first and second electrodes 110 and 130. Lt; / RTI &gt;

Although not shown, a display device including an encapsulation film including an inorganic layer and an organic layer and covering the light emitting diode E and a cover window on the encapsulation film may be formed. At this time, the substrate and the cover window have flexible characteristics, and a flexible display device can be achieved.

The first electrode 110 is made of a relatively high work function material such as indium-tin-oxide (ITO), and the second electrode 130 is made of a material having a relatively low work function value, For example, aluminum (Al) or an aluminum alloy (AlNd). In addition, the organic light emitting layer 120 may have red, green, and blue organic emission patterns.

The organic light emitting layer 120 may have a single layer structure or the organic light emitting layer 120 may have a multi-layer structure to improve the light emitting efficiency. For example, a hole injection layer (HIL) 121, a hole transporting layer (HTL) 122, an emitting material layer (EML) 122, An electron transport layer (ETL) 124, and an electron injection layer (EIL) 125.

At least one of the hole injecting layer 121, the hole transporting layer 122, the light emitting material layer 123, the electron transporting layer 124, and the electron injecting layer 125 may include a retardation fluorescent compound represented by Formula 1 .

For example, the light emitting material layer 123 may include a retardation fluorescent compound represented by Formula 1. [ The light emitting material layer 123 may include the delayed fluorescent compound of the present invention as a dopant material and may be doped to about 1 to 30 wt% with respect to the host, thereby emitting blue light.

The difference between the highest level occupied molecular orbital level (HOMO _Host ) of the _host and the highest level occupied molecular orbital level (HOMO _Dopant ) of the _dopant (| HOMO _Host- HOMO _Dopant |) or the lowest level non occupied molecular orbital level _Host) and the lowest unoccupied molecular orbital level level (LUMO _dopant) difference (the dopant | LUMO _{Host dopant} -LUMO |) must be greater than 0.5eV. This improves the charge transfer efficiency from the host to the dopant.

For example, as a host satisfying such a condition, any one of the following formulas (6) can be used. (DPEPO), 2,8-bis (diphenylphosphoryl) dibenzothiophene (PPT), 2,8-di (9H-carbazol-9-yl) dibenzothiophene (DCzDBT), m 9- (9-phenyl-9H-carbazol-6-yl) -9H-carbazole (CCP) )

[Chemical Formula 6]

At this time, the triplet energy of the dopant is smaller than the triplet energy of the host, the difference (ΔE _ST) of the singlet energy of the triplet energy of the dopant and the dopant is characterized in that not more than 0.3eV. The smaller the ΔE _ST increase the luminous efficiency, and the delayed fluorescent compound of the invention, the energy difference between the singlet and triplet energy of the dopant (ΔE _ST) is about 0.3eV, even if a relatively large singlet state by an electric field (S ₁ ) the exciton and triplet state (T ₁ ) excitons can transition to the intermediate state (I ₁ ). (ΔE _ST ≤0.3)

Meanwhile, the light emitting material layer 123 may include a dopant that is doped to about 1 to 30 wt% with respect to the host material, and emits blue light. The development of a blue host having excellent properties is not sufficient. Therefore, the degree of freedom in host selection can be increased by using the retarded fluorescent compound of the present invention as a host material.

At this time, the triplet energy of the dopant is smaller than the triplet energy of the host, which is the retarded fluorescent compound of the present invention.

In addition, the light emitting material layer 123 may include a retardation fluorescent compound of the present invention as a first dopant material, and may further include a host material and a second dopant material. The sum of doped first and second dopant materials may be, Doped to about 1 to 30 wt% with respect to the host material, thereby emitting blue light. Since the light emitting material layer 123 includes the host material and the first and second dopant materials, luminous efficiency and color tone are further improved.

In this case, the triplet energy of the first dopant, which is a retarding fluorescent compound of the present invention, is smaller than the triplet energy of the host and is larger than the triplet energy of the second dopant. At this time, the difference in energy singlet and triplet energy of the first dopant of the first dopant (ΔE _ST) is characterized in that not more than 0.3eV. The smaller the ΔE _ST increase the luminous efficiency, and delayed fluorescent compound, which is a difference of energy singlet and triplet energy of the first dopant (ΔE _ST) a singlet by an electric field even if a relatively large about 0.3eV of the invention the state ( S ₁ ) excitons and triplet state (T ₁ ) excitons can transition to the intermediate state (I ₁ ). (ΔE _ST ≤0.3)

As described above, the retarded fluorescent compound of the present invention includes both first and second electron donor moieties and electron acceptor moieties, and at least one of the first and second electron donor moieties Either one of the electron acceptor moieties is acridine having a large steric hindrance, so that the luminous efficiency is further improved. Further, a dipole is formed from the electron donor moiety to the electron acceptor moiety to increase the dipole moment inside the molecule, thereby further increasing the luminous efficiency. Further, in the retarding fluorescent compound of the present invention, since the triplet exciton is used for luminescence, the luminescent efficiency is improved.

Accordingly, the luminous efficiency of the organic light emitting diode device including the retarded fluorescent compound of the present invention is also improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

110: first electrode 120: organic light emitting layer
121: Hole injection layer 122: Hole transport layer
123: luminescent material layer 124: electron transport layer
125: electron injection layer 130: second electrode
E: organic light emitting diode

Claims (14)

A second electron donor moiety selected from the group consisting of carbazole, triphenylamine, acridine, and derivatives thereof, wherein the second electron donor moiety is acridine is a substituted or unsubstituted moiety selected from carbazole, triphenylamine, An electron acceptor selected from the group consisting of phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline and derivatives thereof. A retarded fluorescent compound having a molecular formula of a structure bonded to Ti.
1. A retardation fluorescent compound represented by the following formula (1), wherein X is selected from the following formula (2) and Y is selected from the following formula (3).
[Chemical Formula 1]

(2)

(3)

(Wherein R is hydrogen or phenyl).
3. The method of claim 2,
Wherein the delayed fluorescent compound is any one of the following compounds.

3. The method according to claim 1 or 2,
Wherein the difference between the singlet energy and the triplet energy of the retarding fluorescent compound is 0.3 eV or less.
A first electrode;
A second electrode facing the first electrode;
And an organic light emitting layer disposed between the first and second electrodes,
The organic light-
A second electron donor moiety selected from the group consisting of carbazole, triphenylamine, acridine, and derivatives thereof, wherein the second electron donor moiety is acridine is a substituted or unsubstituted moiety selected from carbazole, triphenylamine, An electron acceptor selected from the group consisting of phenyltriazine, dibenzothiophenesulfone, diphenylsulfone, thieno pyrazine, quinoxaline and derivatives thereof. And a retardation fluorescent compound having a molecular formula of a structure to be bonded to the organic compound.
A first electrode;
A second electrode facing the first electrode;
And an organic light emitting layer disposed between the first and second electrodes,
The organic light-
Wherein Y is selected from the following formula (2), and X is selected from the following formula (3).
[Chemical Formula 1]

(2)

(3)

(Wherein R is hydrogen or phenyl).
The method according to claim 6,
Wherein the retarding fluorescent compound is any one of the following compounds.

The method according to claim 5 or 6,
Wherein the difference between the singlet energy and the triplet energy of the retarding fluorescent compound is 0.3 eV or less.
The method according to claim 5 or 6,
Wherein the retarded fluorescent compound is used as a dopant, and the organic light emitting layer further comprises a host.
10. The method of claim 9,
The difference between the highest level occupied molecular orbital level (HOMO _Host ) of the _host and the highest level occupied molecular orbital level (HOMO _Dopant ) of the _dopant (| HOMO _Host- HOMO _Dopant |) or the lowest level non occupied molecular orbital level _Host) and the lowest unoccupied molecular orbital level level (LUMO _dopant) a difference between the dopant (| LUMO _{Host dopant} -LUMO |) is not more than 0.5eV organic light emitting diode device.
The method according to claim 5 or 6,
Wherein the retarded fluorescent compound is used as a host, and the organic light emitting layer further comprises a dopant.
The method according to claim 5 or 6,
Wherein the retarded fluorescent compound is used as a first dopant, the organic light emitting layer further comprises a host and a second dopant,
Wherein the first triplet energy of the first dopant is less than the second triplet energy of the host and greater than the third triplet energy of the second dopant.
The method according to claim 5 or 6,
Wherein the organic light emitting layer includes a hole injection layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, and an electron injection layer,
Wherein at least one of the hole injecting layer, the hole transporting layer, the light emitting material layer, the electron transporting layer, and the electron injecting layer comprises the retarding fluorescent compound.
Claims [1]
The organic light emitting diode device of claim 5 or 6, which is located on the substrate;
An encapsulation film covering the organic light emitting diode device;
And a cover window on the encapsulation film.

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