KR100990181B1 - Red luminescent material and organic electroluminescent device comprising same - Google Patents

Abstract

The present invention relates to a novel red light emitting material and an organic electroluminescent device comprising the same, and the compound of the present invention exhibits excellent chemical and electrical stability, heat resistance, durability, luminous efficiency, luminous brightness and color purity, It can be usefully used as a red light emitting material of the device.

Description

RED LUMINESCENT MATERIAL AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING SAME}             

1, 3 and 4 are schematic cross-sectional views of an organic electroluminescent device according to the present invention,

2 is a schematic cross-sectional view of an organic electroluminescent device manufactured in Example 1 according to the present invention,

Figure 5 shows the UV absorption and photoluminescence (PL) spectrum of the compound prepared in Preparation Example 1 according to the present invention,

Figure 6 shows the electroluminescence (EL) spectrum of the organic electroluminescent device manufactured in Example 1 according to the present invention,

7 shows a voltage-luminance graph of the organic electroluminescent device manufactured in Example 1 according to the present invention.

<Description of Signs of Major Parts of Drawings>

1: substrate 2: transparent electrode (anode)

3: metal electrode (cathode) 4 (4a and 4b): organic layer

5: hole transport layer 6: electron transporting light emitting layer                 

7: hole transporting light emitting layer 8: electron transporting layer

9: hole transport layer 10: light emitting layer

11: electron transport layer A, B, C and D: organic electroluminescent device

The present invention relates to a novel red luminescent material and an organic electroluminescent (EL) device comprising the same, and specifically, red luminescence showing excellent chemical and electrical stability, heat resistance, durability, luminous efficiency, luminous luminance and color purity. A material, and an organic electroluminescent device comprising the same.

Recently, the flat panel display device plays a very important role as a device supporting a highly visual information society based on the Internet, which is rapidly growing. In particular, organic electroluminescent devices (organic EL devices) capable of low-voltage driving with self-luminous type have superior viewing angles, contrast ratios, and the like, as compared to liquid crystal displays (LCDs), which are mainstream flat panel display devices, and require no backlight. Light weight and thinness are possible, and it is advantageous in terms of power consumption. In addition, it is attracting attention as a next generation display device because of its fast response speed, strong external shock, wide usable temperature range, and low manufacturing cost. However, the conventional organic EL device has a high driving voltage and low luminous luminance, luminous efficiency and deterioration characteristics as compared to the inorganic EL device and thus has not been put to practical use.                         

In 1987, CW Tang et al. Used tri (8-quinolinolato) aluminum (hereinafter abbreviated as Alq ₃ ) as a light emitting layer and an amine compound as a hole injecting layer. The organic EL device (Appl. Phys. Lett., 51, 913 (1987)) in which a thin film containing an organic compound emitting green light was laminated, and a coumarin derivative, 4-dicyanomethylene- in an electron transporting light-emitting layer containing Alq _3- Although a device was developed in which light-emitting materials such as 6- (p-dimethylaminostyryl) -2-methyl-4H-pyran (DCM1) were dispersed (J. Appl. Phys., 65 (9), 3610 (1989)) They are difficult to use practically because of low color purity and poor durability.

In addition, CH Chen et al. Introduces an inert alkyl group substituent, for example, tert-butyl group or isopropyl group, instead of the active methyl group located at C-6 of the pyran moiety to suppress the formation of by-products during the reaction. In addition, it was possible to obtain devices with improved luminance and efficiency (Macromol. Symp., 125, 49 (1997)). However, this light emitting material has a long synthesis and purification step, and has a problem in that it is difficult to synthesize a large amount due to low yield.

Therefore, when the conventional organic EL device is used in a full color display device, there are various problems to be solved, such as improvement of luminous efficiency, stability improvement, full colorization, driving method, and panelization technology. Among them, emission color and color purity Improvement and extension of device life have been pointed out as the biggest problems. Particularly, in the case of red, luminous efficiency of about 3 lm / W is required for full colorization, but currently only about 1 lm / W is reached.                         

Conventionally, as a red light emitting material having high color purity, organometallic complexes based on europium are widely known (Appl. Phys. Lett., 65 (17), 2124 (1994)), but organic electroluminescent devices using the same There is a problem that the highest luminance is significantly low. In addition, Japanese Patent Laid-Open No. 1999-329731 discloses a high-brightness red organic electroluminescent device using a specific distyryl compound, and Tao et al. (XT Tao et al.) Red pigment 3- molecularly designed based on DCM1 structure. A red organic EL device was disclosed in which (dicyanomethylene) -5,5-dimethyl-1- (4-dimethylamino-styryl) cyclohexene was doped in Alq ₃ (Appl. Phys. Lett., 78 (3)). , 279 (2001)), the color purity does not reach the reference value.

Accordingly, the present inventors have continued the research, as a result, the red light emitting material having the structure of Formula 1 of the present invention is excellent in chemical and electrical stability, heat resistance, durability, luminous efficiency, luminous brightness and color purity, organic electroluminescence The present invention has been found to be advantageously used in devices.

Accordingly, an object of the present invention is to provide a novel red light emitting material and an organic electroluminescent device comprising the same, which exhibit excellent chemical and electrical stability, heat resistance, durability, luminous efficiency, luminous brightness and color purity.

In order to achieve the above object, the present invention provides a light emitting material represented by the following formula (1).

Where

R ₁ and R ₂ are each independently hydrogen; Unsubstituted or substituted C ₁ -C ₁₀ alkyl; Unsubstituted or substituted C ₁ -C ₁₀ alkoxy; Unsubstituted or substituted C ₁ -C ₁₀ alkyloxy, wherein the substituent is alkyl, halogen, alkoxy, alkyloxy, hydroxy, phenyl or naphthyl; Or a benzo 5-membered heterocycle or a benzo6-membered heterocycle unsubstituted or substituted with 1 to 4 methyl groups; Phenyl, naphthyl, 5- or 6-membered heterocycles, unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group a; Or aminophenyl of formula (2), provided that R ₁ and R ₂ are not hydrogen;

R ₃ and R ₄ are each independently unsubstituted or substituted with 1 to 4 methyl groups, or a benzo 6 membered heterocyclic ring; Phenyl, naphthyl, 5- or 6-membered heterocycles, unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group a; Or aminophenyl of formula (II):

Wherein A ₁ , A ₃ , A ₅ and A ₆ are each independently a group selected from hydrogen or a substituent group a;

A ₂ and A ₄ are each independently hydrogen, R ₈ or R ₉ , wherein A ₁ and A ₂ , or A ₃ and A ₄ may form a hetero ring with each other);

At this time, the substituent group a is

ego,                     

Wherein R ₅ is hydrogen or C ₁ -C ₁₀ alkyl,

R ₆ And R ₇ is C ₁ -C ₁₀ alkylene, preferably methylene, ethylene, propylene, butylene, sec-butylene, tert-butylene, pentylene, 2-phenylisopropylene or trichloromethylene,

R ₈ is phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group b or substituent group c; Or naphthyl unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group c,

R ₉ is phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c; Or naphthyl unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group c,

R ₁₀ is C ₁ -C ₁₀ alkyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c,

R ₁₁ is halogen; C ₁ -C ₁₀ alkoxy; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c,

R ₁₂ is C ₅ -C ₁₀ cycloalkyl; C ₁ -C ₁₀ alkyl; 2-hydroxyethyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c,

Here, the substituent group b is                     

ego,

Substituent group c is

ego,

Wherein R ₁₃ is hydrogen or C ₁ -C ₁₀ alkyl,

R ₁₄ and R ₁₆ are C ₁ -C ₁₀ alkylene,

R ₁₅ is halogen,

R ₁₇ is C ₁ -C ₁₀ alkyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from the substituent group c,

R ₁₈ and R ₁₉ are each independently hydrogen or C ₁ -C ₄ alkyl,

R ₁ and R ₃ or R ₂ and R ₄ may be fused to each other to form a homocyclic or heterocyclic ring.

Preferred among the compounds of the formula

R ₁ and R ₂ are each hydrogen; C ₁ -C ₈ alkyl; Or phenyl unsubstituted or substituted with alkyl, halogen, alkoxy, alkyloxy, hydroxy, phenyl or naphthyl;

R ₃ and R ₄ are amino phenyl substituted with dialkylamino or diarylamino, and R ₁ and R ₃ or R ₂ and R ₄ may be fused to each other to form a homocyclic or heterocyclic ring.

Hereinafter, the present invention will be described in more detail.

According to the present invention, the compound of formula 1 may be prepared by dehydration condensation reaction of dimethylaminomaleonitrile of formula 3, aromatic ketone or aldehyde compound of formula 4, and aromatic ketone or aldehyde compound of formula 5 in the presence of an acid catalyst have.

Wherein R ₁ and R ₂ are as defined above.

In the dehydration and condensation reaction, the compounds of Formula 4 and Formula 5 are preferably used in an amount of 1 to 2 equivalents based on the compound of Formula 3, respectively, and may be performed at a temperature of 70 to 150 ° C. for 1 to 72 hours.

As the acid catalyst, conventional acids such as acetic anhydride and oxalic acid may be used. Among these, acetic anhydride may be used as a solvent and an acid catalyst. Benzene, toluene, xylene, acetic anhydride, etc. can be used as a solvent of the said reaction.

Compounds of formula (1) prepared according to the present invention include both cis and trans forms, which are geometric isomers.

The compound of Chemical Formula 1 prepared according to the present invention may be usefully used in an organic electroluminescent device which emits light of a red region having improved color purity by reducing the half width of the emission wavelength.

Specific examples of the compounds of the present invention are as follows:                     

The present invention also provides an organic electroluminescent device comprising the compound of Formula 1 as a light emitting material alone or in a mixture of two or more kinds in the light emitting layer constituting the organic layer.

The structure of an organic electroluminescent device according to one embodiment of the invention is shown in FIG. 1. As shown in FIG. 1, the organic electroluminescent device of the present invention may be configured in a multi-layered form in which a substrate 1, a transparent electrode 2, an organic layer 4, and a metal electrode 3 are sequentially stacked.

The operating mechanism of the organic EL device generally includes a series of processes such as injection of holes and electrons from an electrode, generation of an electronic excited state by recombination of holes and electrons, and emission from an excited state. As shown in FIG. 2, the organic layer is disposed between two different electrodes. Herein, the organic layer exhibits excellent characteristics of the stacked type device in which the light emitting layer and the charge transport layer are combined, rather than the single layer type device including the light emitting layer. This is because an appropriate combination of the light emitting material and the charge transport material reduces the energy barrier when charge is injected from the electrode, and the charge transport layer binds the holes or electrons injected from the electrode to the light emitting layer region to balance the number of holes and electrons injected. Because it plays a role to achieve.

Therefore, the organic layer of the present invention is preferably an electron transporting layer / light emitting layer / hole transporting layer, an electron transporting light emitting layer / hole transporting layer, or an electron transporting layer / hole aqueous light emitting layer, as shown in Figs. In this case, the hole transporting material used in the hole transporting layer or the hole transporting light emitting layer may include at least one selected from the group consisting of an arylamine derivative, a phthalocyanine compound, and a triphenylene derivative, and is used in the electron transporting layer or the electron transporting emitting layer. The electron transporting material may include a metal complex compound or a nitrogen-containing aromatic ring compound.

Specifically, the organic electroluminescent element A shown in FIG. 1 is a multilayer form in which a substrate 1, a transparent electrode (anode) 2, an organic layer 4, and a metal electrode (cathode) 3 are sequentially stacked. At this time, the substrate 1 is for forming an element, and may use a conventional material such as glass, plastic, or the like; As the transparent electrode (anode) 2, indium lead oxide (hereinafter abbreviated as ITO), SnO ₂ , or the like can be used; The metal electrode (cathode) 3 may use a conventionally known electrode material, preferably a metal such as Li, Mg, Ca, Ag, Al, In, or an alloy thereof, and may have a single layer or a multilayer structure of two or more layers. Can be. In addition, the organic layer 4 may be composed of a single layer or a multilayer of two or more layers including one or more compounds selected from the compounds of Formula 1 of the present invention as light emitting materials. The compound of formula 1 of the present invention may be included alone or in a mixture of two or more kinds of one or more of the layers constituting the organic layer as a light emitting material, for example, Alq ₃ , rubrene (rubrene) and the like Can be added.

The organic electroluminescent device B shown in FIG. 2 is a multilayer form in which a substrate 1, a transparent electrode (anode) 2, an organic layer 4a, and a metal electrode (cathode) 3 are sequentially stacked, among which an organic layer. 4a is a structure in which the hole transport layer 5 and the electron transporting light emitting layer 6 are stacked. At least one compound of the compound of formula 1 of the present invention is included in the electron transporting light emitting layer 6 as a light emitting material. Here, the substrate 1, the transparent electrode (anode) 2 and the metal electrode (cathode) 1 are as mentioned above. The hole transport layer 5 is a conventional hole transport material such as 4,4-bis [N- (1-naphthyl) -N-phenyl-amine] biphenyl (hereinafter abbreviated as α-NPD), N, N-diphenyl-N, N-bis (3-methylphenyl) -1,1-biphenyl-4,4-diamine (hereinafter abbreviated as TPD), poly- (N-vinylcarbazole) (hereinafter as PVCz) Abbreviated-name) etc. can be used individually or in mixture of 2 or more types, and 2 or more layers in which another layer was laminated may be sufficient. The electron transporting light emitting layer 6 may be used alone or in combination of two or more kinds of the compound of the formula (1) as a light emitting material, or other conventionally known electron transport material, for example Alq ₃ , Rubrene and the like may be added alone or in combination of two or more thereof. In addition, in order to improve device characteristics such as efficiency and lifespan, various hole injection layers or anode buffer layers, such as copper phthalocyanine, are inserted between the anode 2 and the hole transport layer 5 as necessary, or the cathode 3 ) And an electron injection layer or a cathode buffer layer, such as LiF, may be inserted between the electron transport layer 6 and the electron transporting light emitting layer 6.

The organic electroluminescent device C shown in FIG. 3 is a multilayered structure in which a substrate 1, an anode 2, an organic layer 4a, and a cathode 3 are sequentially stacked, where the organic layer 4a is a hole transporting light emitting layer ( 7) and the electron transport layer 8 are laminated. At least one compound of the compound of formula 1 of the present invention is included in the hole transporting light emitting layer 7 as a light emitting material. Here, the substrate 1, the transparent electrode (anode) 2 and the metal electrode (cathode) 3 are as mentioned above. The hole transporting light emitting layer 7 may be used alone or in combination of two or more of the compounds of the formula (1) as a light emitting material, or may be added to the compound of the formula (1), for example, other compounds, such as TPD. Further, the electron transport layer 8 is Alq _3, rubrene, etc. may be a conventionally known electron transporting material used alone or in combination of two or more kinds, can be more than two layers of different layers are laminated. In addition, in order to improve device characteristics such as efficiency and lifespan, various hole injection layers or anode buffer layers such as copper phthalocyanine or the like are inserted between the anode 2 and the hole transporting light emitting layer 7 as necessary, or the cathode ( Between the 3) and the electron transport layer 8, various conventional electron injection layers such as LiF, a cathode buffer layer, or the like may be inserted.

The organic electroluminescent device D shown in FIG. 4 is a multilayer form in which a substrate 1, a transparent electrode (anode) 2, an organic layer 4b, and a metal electrode (cathode) 3 are sequentially stacked, wherein the organic layer 4b is a structure in which the hole transport layer 9, the light emitting layer 10, and the electron transport layer 11 are stacked. At least one compound of the compound of Formula 1 of the present invention is included in the light emitting layer 10 as a light emitting material. Here, the substrate 1, the transparent electrode (anode) 2 and the metal electrode (cathode) 1 are as mentioned above. The hole transport layer 9 may be used alone or in combination of two or more of conventional hole transport materials, for example, α-NPD, TPD, PVCz, or the like, or may be two or more layers in which other layers are laminated. The light emitting layer 10 may be used alone or in combination of two or more of the compounds of the formula (1) as a light emitting material, or other compounds, such as Alq ₃ , rubrene or the like to the compound of the formula (1) or You may mix and add 2 or more types. The electron transporting layer 11 may be used alone or as a mixture of two or more kinds of conventionally known electron transporting materials such as Alq ₃ and rubrene, and may be two or more layers in which other layers are laminated. In addition, in order to improve device characteristics such as efficiency and lifespan, various hole injection layers or anode buffer layers such as copper phthalocyanine or the like are inserted between the anode 2 and the hole transport layer 9 as necessary, or the cathode 3 Between the electron transport layer 11 and various conventional electron injection layers such as LiF or cathode buffer layer may be inserted.

The above-mentioned organic electroluminescent elements (Figs. 1 to 4) of the present invention are driven by applying a voltage between the anode 2 and the cathode 3, and the voltage is usually using direct current, but pulse or alternating current may be used. have.

As such, the compound of Chemical Formula 1 of the present invention exhibits excellent chemical and electrical stability, heat resistance, durability, luminous efficiency, luminous brightness and color purity, and thus may be usefully used as a red light emitting material of an organic electroluminescent device.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are not intended to limit the invention only.

Preparation Example 1 Preparation of Red Luminescent Material

The light emitting material of the following structural formula was prepared as follows:

20 g of phenylaldehyde 1-a was dissolved in tetrahydrofuran, and 52 ml (2 equivalents) of methylmagnesium chloride in a 3 M tetrahydrofuran solution was added and reacted at 0 ° C. for 6 hours to yield 17.6 g of compound 1-b (yield) 82%). 16 g of the obtained compound 1-b was dissolved in dichloromethane, 18.9 g (1.5 equivalents) of pyridinium chlorochromate was added thereto, and reacted at room temperature for 36 hours, followed by column chromatography using hexane and ether as a developing solution. 8.2 g (54% yield) were obtained. 1 g of diaminomaleonitrile and 7.5 g (3 equivalents) of the compound 1-c were dissolved in benzene and subjected to dehydration condensation reaction at 90 ° C. for 24 hours under an oxalic acid catalyst. After extracting with dichloromethane, column chromatography was performed using dichloromethane as a developing solution to give 3.1 g (yield 55%) of a solid product.

m.p. 295 ℃

¹ H-NMR (300 MHz, CDCl ₃ ): 7.02-7.11 (m, 4H; aromatic), 0.91 (s, 6H; -N = C (CH ₃ ) -Ar), 3.13 (t, 8H; Ar-N -CH ₂ -CH ₂ -C (CH ₃ ) ₂ -Ar), 1.77 (t, 8H; Ar-N-CH ₂ -CH ₂ -C (CH ₃ ) ₂ -Ar), 1.39 (s, 12H; Ar -N-CH ₂ -CH ₂ -C (CH ₃ ) ₂ -Ar)

UV absorption and photoluminescence spectra of the prepared compound are shown in FIG. 5. From FIG. 5, it can be seen that the maximum UV absorption of the light emitting material appears at around 582 nm and the maximum photoluminescence at about 640 nm.

Preparation Example 2 Preparation of Red Luminescent Material                     

The light emitting material of the following structural formula was prepared as follows:

20 g of phenylaldehyde 2-a was dissolved in tetrahydrofuran, and 66 ml (2 equivalents) of methylmagnesium chloride in a 3 M tetrahydrofuran solution were added and reacted at 0 ° C. for 6 hours to give 17.1 g of compound 2-b (yield) 79%). 16 g of the obtained compound 2-b was dissolved in dichloromethane, 23.8 g (1.5 equivalents) of pyridinium chlorochromate was added thereto, and reacted at room temperature for 36 hours, followed by column chromatography using hexane and ether as a developing solution. 7.9 g (50% yield) were obtained. 1 g of diaminomaleonitrile and 6 g (3 equivalents) of the compound 2-c were dissolved in benzene and subjected to dehydration condensation reaction at 90 ° C. for 24 hours under an oxalic acid catalyst. After extracting with dichloromethane, column chromatography was performed using dichloromethane as a developing solution to give 2.3 g (yield 49%) of a solid product.

m.p. 278 ℃

¹ H-NMR (300 MHz, CDCl ₃ ): 7.09-7.15 (m, 4H; aromatic), 0.9 (s, 6H; -N = C (CH ₃ ) -Ar), 3.28 (t, 8H; Ar-N -CH ₂ -CH ₂ -CH ₂ -Ar), 1.94 (tt, 8H; Ar-N-CH ₂ -CH ₂ -CH ₂ -Ar), 2.74 (t, 8H; Ar-N-CH ₂ -CH ₂ -CH ₂ -Ar)

Preparation Example 3 Preparation of Red Luminescent Material

The light emitting material of the following structural formula was prepared as follows:

20 g of phenylaldehyde 3-a was dissolved in tetrahydrofuran, and 49 ml (2 equivalents) of methylmagnesium chloride in a 3 M tetrahydrofuran solution were added and reacted at 0 ° C. for 6 hours to yield 18 g of compound 3-b (yield). 85%). 16 g of the obtained compound 3-b was dissolved in dichloromethane, 17.9 g (1.5 equivalents) of pyridinium chlorochromate was added thereto, and reacted at room temperature for 36 hours, followed by column chromatography using hexane and ether as a developing solution. 9.4 g (59% yield) were obtained. 1 g of diaminomaleonitrile and 8 g (3 equivalents) of the compound 3-c were dissolved in benzene and subjected to dehydration condensation reaction at 90 ° C. for 24 hours under an oxalic acid catalyst. This was extracted with dichloromethane, and column chromatography was performed using dichloromethane as a developing solution to obtain 3.2 g (yield 53%) of a solid product.

m.p. 305 ℃

¹ H-NMR (300 MHz, CDCl ₃ ): 6.92-7.79 (m, 28H; aromatic), 0.93 (s, 6H; -N = C (CH ₃ ) -Ar)

Example 1:

ITO (Indium Tin Oxide) coated glass (Asahi Glass Co., Ltd., sheet resistance 8 Ω / cm ² ) was ultrasonically washed with a water-based detergent, ultrapure water, isopropyl alcohol and methanol sequentially to make a transparent electrode. . Subsequently, using a mixture of poly- (N-vinylcarbazole) represented by the following formula (6) and TPD (triphenyldiamine derivative) represented by the following formula (7) in a molar ratio of 1: 1, the hole transport layer was 40 nm by spin coating. The film was formed on the ITO film glass at a thickness of. Subsequently, Alq ₃ , rubrene, and the compound prepared in Preparation Example 1 were used as the electron transporting light emitting layer in a weight ratio of 70: 30: 1 to co-deposit at a thickness of 50 nm and a speed of 0.1 nm / second to contact the hole transporting layer. I was. Then, an MgAg alloy (weight ratio 10: 1) was vacuum-deposited so as to have a film thickness of 600 nm in a circular shape having a diameter of 3 mm as a cathode thereon, thereby producing an organic EL device as shown in FIG.

The electroluminescence (EL) spectrum was measured by PR-650 of Photo Research by applying a forward bias DC voltage to the manufactured organic EL device, and is shown in FIG. 6. From FIG. 6, the organic electroluminescent device manufactured according to the present invention has an emission peak showing maximum emission intensity at 645 nm, and the region corresponds to a red emission region.

In addition, a voltage-luminance graph of the organic electroluminescent device is shown in FIG. 7. 7, it can be seen that the organic electroluminescent device exhibits a maximum brightness of 9100 cd / m ² at a 14 V driving voltage.

Example 2

An organic electroluminescent device was manufactured by a method similar to Example 1, except that the compound prepared in Preparation Example 2 was used instead of the compound prepared in Preparation Example 1. The manufactured organic electroluminescent device had an emission peak showing the maximum emission intensity at 643 nm corresponding to the red emission region, and showed a luminance of 8500 cd / m ^{2 with} a 13 V driving voltage.

Example 3

An organic electroluminescent device was manufactured according to the same method as Example 1 except for using the compound prepared in Preparation Example 3, instead of the compound prepared in Preparation Example 1. The manufactured organic electroluminescent device had an emission peak showing the maximum emission intensity at 635 nm corresponding to the red emission region, and exhibited a luminance of 8700 cd / m ^{2 with} a 13 V driving voltage.

The light emitting material of Chemical Formula 1 according to the present invention exhibits excellent chemical and electrical stability, heat resistance, durability, light emitting efficiency, light emission luminance and color purity, and thus may be usefully used as a red light emitting material of an organic electroluminescent device.

Claims (7)

Red light emitting material represented by the formula (1): Formula 1

Where R ₁ and R ₂ are each independently hydrogen; Unsubstituted or substituted C ₁ -C ₁₀ alkyl; Unsubstituted or substituted C ₁ -C ₁₀ alkoxy; Wherein the substituent is alkyl, halogen, alkoxy, alkyloxy, hydroxy, phenyl or naphthyl; Or a benzo 5-membered heterocycle or a benzo6-membered heterocycle unsubstituted or substituted with 1 to 4 methyl groups; Phenyl, naphthyl, 5- or 6-membered heterocycles, unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group a; Or aminophenyl of formula 2a, provided that neither R ₁ nor R ₂ is hydrogen; Formula 2a

Wherein A ₁ , A ₃ , A ₅ and A ₆ are each independently a group selected from hydrogen or a substituent group a; A ₂ and A ₄ are each independently hydrogen, alkyl, R ₈ or R ₉ , Wherein A ₁ and A ₂ , or A ₃ and A ₄ may form a hetero ring with each other); R ₃ and R ₄ are aminophenyl of Formula 2b: Formula 2b

Wherein A ′ ₁ and A ′ ₃ are each independently a methylene group unsubstituted or substituted with one or two methyl groups, or oxygen, and A ′ ₅ and A ′ ₆ are each independently hydrogen or a substituent group a Is a group selected from); At this time, the substituent group a is

ego, Wherein R ₅ is hydrogen or C ₁ -C ₁₀ alkyl, R ₆ and R ₇ are each independently C ₁ -C ₁₀ alkylene, 2-phenylisopropylene or trichloromethylene, R ₈ is phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group b or substituent group c; Or naphthyl unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group c, R ₉ is phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c; Or naphthyl unsubstituted or substituted 1 to 4 with one or more substituents selected from substituent group c, R ₁₀ is C ₁ -C ₁₀ alkyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c, R ₁₁ is halogen; C ₁ -C ₁₀ alkoxy; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c, R ₁₂ is C ₅ -C ₁₀ cycloalkyl; C ₁ -C ₁₀ alkyl; 2-hydroxyethyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from substituent group c, Here, the substituent group b is

ego, Substituent group c is

ego, Wherein R ₁₃ is hydrogen or C ₁ -C ₁₀ alkyl, R ₁₄ and R ₁₆ are C ₁ -C ₁₀ alkylene, R ₁₅ is halogen, R ₁₇ is C ₁ -C ₁₀ alkyl; Or phenyl unsubstituted or substituted one or two with one or more substituents selected from the substituent group c, R ₁₈ and R ₁₉ are each independently hydrogen or C ₁ -C ₄ alkyl, R ₁ and R ₃ or R ₂ and R ₄ may be fused to each other to form a homocyclic or heterocyclic ring. The method of claim 1, R ₁ and R ₂ are each hydrogen; C ₁ -C ₈ alkyl; Or phenyl unsubstituted or substituted with alkyl, alkoxy, hydroxy, or phenyl; R ₁ and R ₃ or R ₂ and R ₄ may be fused to each other to form a homo- or hetero-ring, a red light emitting material. A compound of formula 1 according to claim 1 comprising condensation of dimethylaminomaleonitrile of formula 3, aromatic ketone or aldehyde compound of formula 4, and aromatic ketone or aldehyde compound of formula 5 in the presence of an acid catalyst Manufacturing method of: Formula 3

Formula 4

Formula 5

Wherein R ₁ and R ₂ are as defined in claim 1. The method of claim 3, wherein The compound of Formula 4 and Formula 5 is used in the amount of 1 to 2 equivalents to the compound of Formula 3, respectively. The method of claim 3, wherein Condensation reaction is carried out at 70 to 150 ℃ for 1 to 72 hours. An organic electroluminescent device in which a substrate, a transparent electrode, an organic layer, and a metal electrode are sequentially stacked, wherein the organic layer comprises a compound of formula 1 according to claim 1 as a light emitting material. The method of claim 6, An organic electroluminescent element, wherein the organic layer is composed of an electron transporting layer / light emitting layer / hole transporting layer, an electron transporting light emitting layer / hole transporting layer, or an electron transporting layer / hole transporting light emitting layer.

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