KR20160068641A - Delayed Fluorescence compound, and Organic light emitting diode device and Display device using the same - Google Patents

Abstract

Provided is a delayed fluorescence compound having a molecular structure having a bond between a benzene ring of benzo[4,5]thieno[2,3-b]quinoxaline as an electron acceptor moiety and an electron doner moiety selected from carbazole, phenylcarbazole, acridine, or phenylacridine. The present invention is to solve a problem of low quantum efficiency in a fluorescent substance.

Description

TECHNICAL FIELD [0001] The present invention relates to a retardation fluorescent compound, an organic light emitting diode (OLED) device, and a display device using the retardation fluorescent compound.

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 provides a process for producing a benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety having a molecular formula of a structure in which an electron donor moiety is bonded to a benzene ring Thereby providing a fluorescent compound.

The electron donor moiety may be selected from carbazole, phenyl carbazole, acridine or phenylacridine.

That is, the retarded fluorescent compound of the present invention is represented by the following formula: m and n are integers from 0 to 2, m or n is 0, and each of D1 and D2 is a carbazole, phenylcarbazole, May be selected from the group consisting of: < RTI ID = 0.0 >

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 delayed fluorescent compound of the present invention has a structure in which a benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety and an electron donor moiety are bonded, The charge is easily moved within the light emitting layer and the light emitting efficiency is improved. Therefore, 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.

Particularly, benzo [4,5] thieno [2,3-b] quinoxaline having strong electron accepting properties is used as an electron acceptor moiety and electron acceptor moiety and electron donor moiety are contained in the molecule, The efficiency of use of the state excitons increases.

Further, since carbazole or acridine is used as an electron donor moiety to form a large back angle with benzo [4,5] thieno [2,3-b] quinoxaline, the red shift of light emitted from the light- the red shift problem can be minimized.

The electron donor moiety and the electron acceptor moiety are bonded in the molecule and the superposition of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is reduced A field activated delayed fluorescence complex is formed to further improve the luminous efficiency of the retarded fluorescent compound.

Therefore, the organic light emitting diode device and the display device including the retarded fluorescent compound of the present invention can improve the luminous efficiency and realize a high quality image.

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 showing the HOMO and LUMO distributions of Compound 1 according to the present invention.
3A and 3B are views showing the HOMO and LUMO distributions of Compound 2 according to the present invention.
4A and 4B are diagrams showing the HOMO and LUMO distributions of compound 3 according to the present invention.
5A and 5B are diagrams showing the HOMO and LUMO distributions of compound 4 according to the present invention.
6A and 6B are diagrams showing the HOMO and LUMO distributions of Compound 5 according to the present invention.
Figures 7a and 7b, respectively, show the HOMO and LUMO distributions of compound 6 according to the invention.
8A and 8B are diagrams showing the HOMO and LUMO distributions of compound 7 according to the present invention.
Figures 9a and 9b, respectively, show the HOMO and LUMO distributions of compound 8 according to the present invention.
10A and 10B are diagrams showing the HOMO and LUMO distributions of Compound 9 according to the present invention.
11A and 11B are diagrams showing the HOMO and LUMO distributions of compound 10 according to the present invention.
12A and 12B are views showing the HOMO and LUMO distributions of Comparative Compound 1, respectively.
13A and 13B are views showing the HOMO and LUMO distributions of Comparative Compound 2, respectively.
14A and 14B, respectively, show the HOMO and LUMO distributions of Comparative Compound 3. FIG.
15A and 15B are diagrams showing the HOMO and LUMO distributions of Comparative Compound 4, respectively.
16A and 16B are diagrams showing the HOMO and LUMO distributions of Comparative Compound 4, respectively.
17A and 17B are views showing the HOMO and LUMO distributions of Comparative Compound 4, respectively.
18A to 18C are graphs showing delayed fluorescence characteristics of a retarded fluorescent compound according to an embodiment of the present invention.
19 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 an electron donor mordant selected from carbazole, phenylcarbazole, acridine or phenylacridine in a benzene ring of benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety The present invention provides a retarded fluorescent compound having a molecular formula of a structure in which Ti is bonded.

In another aspect, the present invention provides a compound represented by the following general formula (1), wherein each of D1 and D2 is selected from the following general formula (2), m and n are integers of 0 to 2, one of m or n is 0, Each independently provide a delayed fluorescent compound selected from C1 to C10 alkyl.

[Chemical Formula 1]

(2)

The retarded fluorescent compound of the present invention may be any of the following compounds.

In the retarding fluorescent compound of the present invention, the difference between the singlet energy and the triplet energy of the retarding 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, , 5] thieno [2,3-b] quinoxaline A benzene ring of an electron acceptor moiety has a molecular structure of a structure in which an electron donating moiety selected from carbazole, phenylcarbazole, acridine or phenylacridine is bonded And a retardation fluorescent compound having a light-emitting property.

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, Each of D1 and D2 is selected from the following formula (2), m and n are integers from 0 to 2, and either m or n is 0, and each of R1 and R2 is independently selected from C1 to C10 alkyl And an organic light-emitting diode device including the selected delayed fluorescent compound.

[Chemical Formula 1]

(2)

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 another aspect, the present invention provides a light emitting device comprising a substrate, an organic light emitting diode device disposed on the substrate, an encapsulation film covering the organic light emitting diode device, and a cover window on the encapsulation film, A display device is provided.

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 may be a benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor such as benzo [4,5] thieno [2,3- acceptor moiety and an electron donor moiety are bonded to each other and represented by the following formula (1).

[Chemical Formula 1]

That is, the electron donating moieties D1 and D2 are bonded to the benzene ring of benzo [4,5] thieno [2,3-b] quinoxaline.

Here, m and n are integers of 0 to 2, and either m or n is 0. That is, the structure in which the electron donating moiety D1 is bonded to the benzene rings 2,3 of the quinoxaline moiety of benzo [4,5] thieno [2,3-b] quinoxaline as shown in Formula 2-1 below Or has a structure in which an electron donating moiety D1 is bonded to the benzene ring 2 position of the quinoxaline moiety of benzo [4,5] thieno [2,3-b] quinoxaline as shown in Formula 2-2 below . Further, an electron donating moiety D2 is bonded to the benzene rings 2,3 of the benzothiophene moiety of benzo [4,5] thieno [2,3-b] quinoxaline as shown in Formula 2-3 below The electron donating moiety D2 is bonded to the benzene ring 2 position of the benzothiophene moiety of the benzo [4,5] thieno [2,3-b] quinoxaline as shown in the following chemical formula 2-4 Can have a bonded structure.

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Chemical Formula 2-4]

In Formula 1, each of the electron donating moieties D1 and D2 is selected from carbazole, phenylcarbazole, acridine, or phenylacridine. For example, each of the electron donor moieties D1 and D2 may be selected from the substances represented by the following formula (3).

(3)

In Formula 3, each of R 1 and R 2 may independently be a C 1 to C 10 alkyl.

Such a retarded fluorescent compound has a structure in which a benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety and an electron donor moiety are bonded to each other, The efficiency is improved.

That is, since the retarded fluorescent compound of the present invention includes both the electron donating moiety and the electron accepting moiety, the charge can easily move within the molecule and the luminous efficiency can be improved. Further, since the triplet exciton is used for luminescence, the luminescent efficiency of the retarded fluorescent compound is improved.

Particularly, benzo [4,5] thieno [2,3-b] quinoxaline having strong electron accepting properties is used as an electron acceptor moiety and electron acceptor moiety and electron donor moiety are contained in the molecule, The efficiency of use of the state excitons increases. Further, since carbazole or acridine is used as an electron donor moiety to form a large back angle with benzo [4,5] thieno [2,3-b] quinoxaline, the red shift of light emitted from the light- the red shift problem can be minimized.

The electron donor moiety and the electron acceptor moiety are bonded in the molecule and the superposition of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is reduced An 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.

In addition, since the electron acceptor moiety 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 retarded fluorescent compound of the present invention is a compound containing benzo [4,5] thieno [2,3-b] quinoxaline as an electron acceptor moiety and having a carbazole, phenylcarbazole, acridine or phenylacridine, the luminous efficiency of the triplet state exciton is increased and the color tone is improved.

FIGS. 2A to 17B are graphs showing the HOMO and LUMO distributions of the compounds 1 to 16 of the formula 4, and the HOMO, LUMO and band gap energies of these compounds are shown in Table 1.

As shown in FIGS. 2A to 17B and Table 1, in the retarded fluorescent compound of the present invention, separation of HOMO and LUMO occurs well and has an energy band gap of 3.5 eV or more. Therefore, the triplet state exciton becomes a FADF compound participating in luminescence and emits deep blue light.

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 C

[Reaction Scheme 1-1]

In N2 purging, Compound A was dissolved in diethyl ether and then 1.2 equivalents of Compound B (dissolved in MC) was slowly dropped at 0 占 폚. After stirring at room temperature for 3 hours, 3 equivalents of alumimium chloride was slowly dropped at 0 占 폚. After stirring for 12 hours, 1M HCl solution was slowly added to terminate the reaction and extract. A white solid compound C was obtained through a short-column using hexane.

(2) Synthesis of Compound E

[Reaction Scheme 1-2]

In N2 purging, compound C, 1.5 equivalents of compound D was added to acetic acid and stirred at 90 &lt; 0 &gt; C. After 16 hours, the reaction was terminated by adding water. MC and hexane to obtain Compound E in the form of a white solid.

(3) Synthesis of Compound 1

[Reaction 1 - 3]

Compound E, 1.2 equivalents of compound F, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚 under N2 purging under nitrogen atmosphere (N2 purging). After 14 hours, the reaction mixture was extracted with water. Hexane: Compound (1) was obtained as a white solid through a column using an electric field solvent of MC (9: 1).

2. Synthesis of Compound 2

(1) Synthesis of Compound H

[Reaction Scheme 2-1]

In N 2 purging, compound C, 1.5 equivalents of compound G was added to acetic acid and stirred at 90 ° C. After 16 hours, the reaction was terminated by adding water. MC and hexane to obtain Compound H in a white solid state.

(2) Synthesis of Compound 2

[Reaction Scheme 2-2]

In N2 purging, compound H, 2.3 equivalents of compound F, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚. After 18 hours, the reaction mixture was poured into water and extracted. Compound 1 was obtained as a white solid through a column using an Hexane: MC (3: 1) electric field solvent.

3. Synthesis of Compound 3

[Reaction Scheme 3]

In N2 purging, compound E, 1.3 equivalents of compound I, 0.05 equivalents of Pd (0), and 4.0 equivalents of potassium carbonate were added to toluene and stirred in an oil bath at 80 占 폚. After 12 hours, water was added to the reaction product and extracted. A white solid compound 3 was obtained through column using hexane: MC (4: 1) electric field solvent.

4. Synthesis of Compound 4

[Reaction Scheme 4]

In N2 purging, compound h, 2.3 equivalents of compound I, 0.05 equivalents of Pd (0), and 4.0 equivalents of potassium carbonate were added to toluene and stirred in an oil bath at 80 占 폚. After 16 hours, the reaction mixture was extracted with water. A white solid compound 4 was obtained through column using hexane: EA (4: 1) electric field solvent.

5. Synthesis of Compound 5

(1) Synthesis of Compound K

[Reaction Scheme 5-1]

In N2 purging, Compound J was dissolved in diethyl ether and 1.2 equivalents of Compound B (dissolved in MC) was slowly dropped at 0 占 폚. After stirring at room temperature for 3 hours, 3 equivalents of alumimium chloride was slowly dropped at 0 占 폚. After stirring for 12 hours, 1M HCl solution was slowly added to terminate the reaction and extract. A white solid compound K was obtained through a short-column using hexane.

(2) Synthesis of Compound M

[Reaction Scheme 5-2]

In N2 purging, compound K, 1.5 equivalents of compound L was added to acetic acid and stirred at 90 &lt; 0 &gt; C. After 16 hours, the reaction was terminated by adding water. MC and hexane to obtain Compound M in a white solid state.

(3) Synthesis of Compound 5

[Reaction Scheme 5-3]

In N2 purging, compound M, 1.2 equivalents of compound F, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚. After 12 hours, water was added to the reaction product and extracted. Compound 5 was obtained as a white solid through a column using hexane: MC (5: 1) electric field solvent.

6. Synthesis of Compound 6

(1) Synthesis of Compound O

[Reaction Scheme 6-1]

In N2 purging, compound N was dissolved in diethyl ether and 1.2 equivalents of compound B (dissolved in MC) was slowly dropped at 0 占 폚. After stirring at room temperature for 3 hours, 3 equivalents of alumimium chloride was slowly dropped at 0 占 폚. After stirring for 12 hours, 1M HCl solution was slowly added to terminate the reaction and extract. A white solid compound O was obtained through a short-column using hexane.

(2) Synthesis of Compound P

[Reaction Scheme 6-2]

In a nitrogen atmosphere (N2 purging), compound O, 1.5 equivalents of compound L was added to acetic acid and stirred at 90 &lt; 0 &gt; C. After 16 hours, the reaction was terminated by adding water. MC and hexane to obtain Compound (P) in a white solid state.

(3) Synthesis of Compound 6

[Reaction Scheme 6-3]

Compound P, 2.3 equivalents of compound F, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane, and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚 in a nitrogen atmosphere (N2 purging). After 18 hours, the reaction mixture was poured into water and extracted. Hexane: Compound (6) was obtained as a white solid through a column using an electric field solvent of MC (3: 2).

7. Synthesis of Compound 7

[Reaction Scheme 7]

In N 2 purging, compound M, 1.3 equivalents of compound I, 0.05 equivalents of Pd (0), and 4.0 equivalents of potassium carbonate were added to toluene and stirred in an oil bath at 80 ° C. After 13 hours, the reaction mixture was extracted with water. Compound 7 in the form of a white solid was obtained through a column using an Hexane: MC (4: 1) electric field solvent.

8. Synthesis of Compound 8

[Reaction Scheme 8]

Compound P, 2.3 equivalents of compound I, 0.05 equivalents of Pd (0), and 4.0 equivalents of potassium carbonate were placed in toluene and stirred in an oil bath at 80 占 폚 under nitrogen atmosphere (N2 purging). After 20 hours, the reaction mixture was extracted with water. A white solid compound 8 was obtained through column using hexane: EA (3: 1) electric field solvent.

9. Synthesis of Compound 9

(1) Synthesis of Compound R

[Reaction Scheme 9-1]

Compound Q (46.9 mmol) was mixed with a methanol solvent and stirred under 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 DEG C for 12 hours or longer. After completion of the reaction, the solvent was removed, and distilled water and ethyl acetate were added to extract. Water was removed from the extracted organic layer using magnesium sulfate. After the remaining solvent was removed, the product was wet-purified through column chromatography using hexane and ethyl acetate to obtain a dark yellow liquid-state compound R.

(2) Synthesis of compound S

[Reaction Scheme 9-2]

Compound R (38.1 mmol) was stirred in a tetrahydrofuran solvent in a nitrogen atmosphere and then methylmagnesium bromide (4.6 eq.) Was slowly dropped. Followed 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 using magnesium sulfate, and the remaining solvent was removed. The product was wet-purified by column chromatography using lexane and ethyl acetate to obtain Compound S in a yellow liquid state.

(3) Synthesis of compound T

[Reaction Scheme 9-3]

Compound S (33.1 mmol) was stirred with excess phosphoric acid (160 ml) at room temperature. After stirring for more than 16 hours, 200-250 ml of distilled water was slowly added. Thereafter, the mixture was stirred for 0.5-1 hours, and the precipitated solid was filtered. The filtered solid was extracted with an aqueous solution of sodium hydroxide and dichloromethane, and water was removed from the organic layer using magnesium sulfate. The remaining organic solvent was removed to obtain Compound T in a white solid state.

(4) Synthesis of Compound 9

[Reaction Scheme 9-4]

In N2 purging, compound E, 1.2 equivalents of compound T, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane, and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚. After 16 hours, water was added to the reaction and extracted. Compound 9 was obtained in the form of a white solid through a column using an Hexane: MC (3: 1) electric field solvent.

10. Synthesis of Compound 10

[Reaction Scheme 10]

In N2 purging, Compound H, 2.2 equivalents of compound T, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane, and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚. After 18 hours, the reaction mixture was poured into water and extracted. A white solid compound 10 was obtained through column using hexane: MC (1: 1) electric field solvent.

11. Synthesis of Compound 11

(1) Synthesis of Compound V

[Reaction Scheme 11-1]

Compound T, 0.8 equivalents of compound U, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane, and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚 under N 2 purging under N 2 purging. After 11 hours, water was added to the reaction product and extracted. A white solid compound V was obtained through column using hexane: MC (9: 1) electric field solvent.

(2) Synthesis of Compound W

[Reaction Scheme 11-2]

In a nitrogen environment (N2 purging), Compound V, 1.5 equivalent of Bu-Li was added to ether and stirred at -78 [deg.] C. After 4 hours of reaction, 1.2 equivalent of triethyl borate was added and the mixture was stirred at -78 캜 for 30 minutes. Dry ice bath was removed and the reaction temperature was raised to room temperature. After the reaction for 14 hours, 30 ml of HCl (in DI water) was added and the organic solvent was removed. After all of the organic solvent was removed, the solid precipitated in water was filtered to obtain a compound W in a white solid state.

(3) Synthesis of Compound 11

[Reaction Scheme 11-3]

Compound E, 1.3 equivalents of compound W, 0.05 equivalent of Pd (0) and 4.0 equivalents of potassium carbonate were placed in toluene and stirred in an oil bath at 80 占 폚 under N 2 purging under nitrogen atmosphere. After 11 hours, water was added to the reaction product and extracted. Compound 11 was obtained as a white solid through a column using an Hexane: MC (2: 1) electric field solvent.

12. Synthesis of Compound 12

[Reaction Scheme 12]

In N2 purging, compound H, 2.3 equivalents of compound W, 0.05 equivalent of Pd (0) and 4.0 equivalents of potassium carbonate were placed in toluene and stirred in an oil bath at 80 占 폚. After 16 hours, the reaction mixture was extracted with water. A white solid compound 12 was obtained through column using hexane: EA (3: 1) electric field solvent.

13. Synthesis of Compound 13

[Reaction Scheme 13]

In N2 purging, compound M, 1.2 equivalents of compound T, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚. After 12 hours, water was added to the reaction product and extracted. A white solid compound 13 was obtained through column using hexane: MC (4: 1) electric field solvent.

14. Synthesis of Compound 14

[Reaction Scheme 14]

Compound P, 2.3 equivalents of compound T, 1.0 equivalent of CuI, 3.5 equivalents of diaminocyclohexane, and 4.0 equivalents of potassium phosphate were placed in 1,4-dioxane and stirred in an oil bath at 90 占 폚 under N 2 purging under N 2 purging. After 18 hours, the reaction mixture was poured into water and extracted. Compound 14 was obtained as a white solid through a column using an Hexane: MC (1: 1) electric field solvent.

15. Synthesis of Compound 15

[Reaction Scheme 15]

In N2 purging, compound M, 1.3 equivalents of compound W, 0.05 equivalent of Pd (0), and 4.0 equivalents of potassium carbonate were added to toluene and stirred in an oil bath at 80 占 폚. After 13 hours, the reaction mixture was extracted with water. Compound 15 in the form of a white solid was obtained through a column using an electric field solvent of hexane: MC (3: 1).

16. Synthesis of Compound 16

[Reaction Scheme 16]

Compound P, 2.3 equivalents of compound W, 0.05 equivalent of Pd (0), and 4.0 equivalents of potassium carbonate were placed in toluene and stirred in an oil bath at 80 占 폚 under nitrogen atmosphere (N2 purging). After 20 hours, the reaction mixture was extracted with water. Compound 16 in the form of a white solid was obtained through column using hexane: EA (3: 1) electric field solvent.

The mass spectrometry results of the compounds 1 to 16 are shown in Table 2.

(Ref) and the compounds 1 and 5 (Com1, Com5) were measured under O ₂ free conditions using a Quantarus tau equipment manufactured by Hamamatsu Co. The measurement results are shown in Tables 3 and 18A and 18C .

[Chemical Formula 5]

As shown in Table 3 and FIG. 18A, the compound (Ref) of Formula 5 shows a delayed fluorescence phenomenon of several hundred nanoseconds (ns), whereas, as shown in Tables 3 and 18b and 18c, And Compound 5 (Com1, Com5) showed delayed fluorescent phenomena of tens of nanoseconds (ns), respectively.

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 an electron donating moiety and an electron accepting moiety at the same time in one molecule, and electrons can easily migrate within 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 Δμ form a linear graph. Conversely, when Δf and Δμ 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 device using the delayed fluorescent compound of the present invention and the organic light emitting diode device using the comparative compound of Formula 5 will be described.

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. And the base pressure was about 10 ^-6 to 10 ^-7 Torr. Then, on the anode ITO, i) a hole injecting layer of 40 Å (NPB (N, N'-di (naphthalen- benzidine), ii) mCP (N, N'-Dicarbazolyl-3,5-benzene), iii) luminescent material layer 200 Å (bis {2- {di (phenyl) ether oxide / dopant (12%), iv) phenyl-2-benzimidazole-benzene, v) electron injecting layer 10 Å (LiF) Respectively.

(1) Experimental Example 1 (Ex1)

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

(2) Experimental Example 2 (Ex2)

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

(3) Experimental Example 3 (Ex3)

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

(4) Experimental Example 4 (Ex4)

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

(5) Experimental Example 5 (Ex5)

In the above-described device, Compound 9 was used as a dopant of the light emitting material layer.

(6) Experimental Example 6 (Ex6)

In the above-described device, Compound 10 was used as a dopant of the light emitting material layer.

(7) Experimental Example 7 (Ex7)

In the above-described device, the compound 13 was used as a dopant of the light emitting material layer.

(8) Experimental Example 8 (Ex8)

In the above-described device, Compound 14 was used as a dopant of the light emitting material layer.

(9) Comparative Example (Ref)

In the above-mentioned device, the compound (Ref) of the above formula (5) was used as a dopant of the light emitting material layer.

As shown in Table 4, in the device using the retarding fluorescent compound of the present invention, color (or color purity) and luminous efficiency were improved. That is, even in the compound containing carbazole as an electron donor moiety, its characteristics are greatly changed according to the electron acceptor moiety, and benzo [4,5] thieno [2,3- benzo [4,5] thieno [2,3-b] quinoxaline, the color tone is improved, and the luminous efficiency is greatly improved by the participation of triplet excitons.

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

As shown, 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 is a compound having both electron donor moiety and electron acceptor moiety and having benzo [4,5] thieno [2 , 3-b] quinoxaline is used as an electron acceptor moiety, the luminous efficiency is improved.

That is, since a dipole is formed from the electron donor moiety to the electron acceptor moiety to increase the dipole moment inside the molecule, the luminous efficiency is improved. In particular, since the triplet exciton is used for light emission, .

Further, the back angle between the electron acceptor moiety and the electron acceptor moiety is increased, so that deep-beam light is emitted.

Therefore, the organic light emitting diode device including the retarded fluorescent compound of the present invention can improve the luminous efficiency and realize a high quality image.

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 (13)

Benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety is attached to an electron donor moiety selected from carbazole, phenylcarbazole, acridine or phenylacridine Delayed fluorescent compound having molecular formula of structure.
Wherein each of D1 and D2 is selected from the following formula (2), m and n are integers from 0 to 2, and either m or n is 0.
[Chemical Formula 1]

(2)

(In the above formula (2), each of R 1 and R 2 is independently selected from C 1 to C 10 alkyl.)
3. The method of claim 2,
Wherein the delayed fluorescent compound is any one of the following compounds.

3. The method of claim 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-
Benzo [4,5] thieno [2,3-b] quinoxaline electron acceptor moiety is attached to an electron donor moiety selected from carbazole, phenylcarbazole, acridine or phenylacridine Wherein the organic light emitting diode device comprises a retardation fluorescent compound having a molecular formula of the structure.
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 each of D1 and D2 is selected from the following formula (2), m and n are integers from 0 to 2, and either m or n is 0.
[Chemical Formula 1]

(2)

(In the above formula (2), each of R 1 and R 2 is independently selected from C 1 to C 10 alkyl.)
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.
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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