KR101309660B1 - Naphthyl phenyl derivatives and organoelectroluminescent device employing the same - Google Patents

Abstract

The present invention relates to a naphthylphenyl derivative and an organic electroluminescent device using the same, and more particularly, to an organic electroluminescent device using a naphthylphenyl derivative which is a blue light emitting compound that can be easily applied by deposition and solution processes. .

Description

Naphthyl phenyl derivatives and organoelectroluminescent device employing the same}

The present invention relates to a naphthylphenyl derivative and an organic electroluminescent device using the same, and more particularly, to an organic electroluminescent device using a naphthylphenyl derivative which is a blue light emitting compound that can be easily applied by deposition and solution processes. .

An organic electroluminescent device (organic EL device) is an active light emitting type using a phenomenon in which light is generated while electrons and holes are combined in an organic film when a current flows through a thin film of fluorescent or phosphorescent organic compound (hereinafter referred to as an organic film). As a display element, it is lightweight, has a simple structure, a simple manufacturing process, and secures a wide viewing angle at high image quality. In addition, it is possible to realize a video perfectly, to realize high color purity, and to have electrical characteristics suitable for portable electronic devices with low power consumption and low voltage driving.

The organic electroluminescent device can be classified into a low molecular organic EL device and a polymer EL device according to the material for forming the organic film.

The low molecular organic EL device has advantages in that it is simple to synthesize a light emitting material, is easy to purify with high purity, and can easily implement three primary color pixels. However, since the organic film is formed using the vacuum deposition method, it is difficult to apply to the large-area process using methods such as spin coating and inkjet printing, and for practical applications, unsolved problems such as improvement of quantum efficiency, prevention of crystallization of thin film, and improvement of color purity The task remains. In addition, the low molecular organic EL device must use a multilayer structure such as a hole injection layer, a hole transport layer, an electron transport layer, a hole suppression layer, etc. in order to obtain high efficiency and high luminance light emission characteristics. However, the organic film such as the hole injection layer, the hole transport layer, the electron transport layer, the hole suppression layer should be thermally and electrically stable during device operation. The reason is that when a voltage is applied, molecules with low thermal stability due to heat generated in the device have low morphological stability, resulting in rearrangement, and localization of crystallization, resulting in low luminous efficiency. It is shortened.

On the other hand, since it has been reported that a polymer organic EL device emits light when electricity is applied to poly (1,4-phenylenevinylene), which is a π-conjugated polymer, active research is being conducted. The π-conjugated polymer has a chemical structure with alternating single bonds (or sigma bonds) and double bonds (or π bonds), and has π electrons that can move relatively freely along the bond chain without being localized. Due to this semiconducting nature, when the π-conjugated polymer is applied to the light emitting layer of the EL device, the entire visible light region corresponding to the band gap between the highest occupied molecular orbital (HOMO) and the lower unoccupied molecular orbital (LUMO) Light can be easily obtained through molecular design, and a thin film can be simply formed by spin coating or printing method, so the manufacturing process is simple and large area can be reduced at low cost. However, polymer EL devices have a lower luminous efficiency than low molecular EL devices, resulting in a problem of deterioration of lifetime characteristics of the devices due to deterioration of the light emitting polymer. This is because defects that promote deterioration in the molecular chain are present in the process of synthesis due to the nature of the polymer material, and it is difficult to obtain a high purity material due to difficulty in purifying impurities. Therefore, it is urgent to develop a new material that can compensate for the disadvantages while accepting the advantages of the above-mentioned polymers and low molecules.

The technical problem to be achieved by the present invention is to complement the disadvantages of the known low-molecules and polymers and introduce their advantages, there is no molecular defects, excellent thermal stability and crystal stability, easy to purify and form a thin film using a soluble solvent It is to provide a naphthylphenyl derivative which is easy to follow.

Another object of the present invention is to provide an organic EL device having improved luminance, driving voltage, and luminous efficiency.

In order to achieve the above technical problem, the present invention provides a naphthylphenyl derivative represented by the following Chemical Formula 1.

[Formula 1]

Wherein Ar ₁ , Ar ₂ and Ar ₃ are each independently a substituted or unsubstituted aryl group having 6 to 40 carbon atoms; The substituents include one or more substituents selected from alkyl groups of 1 to 10 carbon atoms, alkoxy groups of 1 to 10 carbon atoms, amine groups of 1 to 10 carbon atoms, aryl groups of 6 to 10 carbon atoms, and heteroaryl groups of 4 to 20 carbon atoms. Selected from the group, and one or more selected from Ar ₁ , Ar _2, and Ar ₃ may be connected to each other.

Another technical problem of the present invention is an organic electroluminescent device comprising an organic film between a pair of electrodes, wherein the organic film comprises an organic electroluminescent device comprising the above-mentioned naphthylphenyl derivative.

In particular, the present invention, naphthylphenyl derivative represented by the formula (1) of the present invention has a phenylnaphthyl unit as the central molecular structure and the aromatic group at the carbon positions 2 and 3 and 5 of the phenyl naphthyl units, respectively It has a structure introduced.

Due to these structural features, the present invention provides that the naphthylphenyl derivatives of formula (1) compensate for the disadvantages of the low molecular / polymeric materials and introduce their advantages, i.e. free from molecular defects, easy to purify, and also with various soluble solvents. Thin films of thickness can be easily formed.

The compound of Formula 1 of the present invention exhibits particularly excellent properties of the naphthylphenyl structure in which the aromatic groups of Ar ₁ , Ar ₂ and Ar ₃ are substituted, and thus, an organic electroluminescent device using the same, and more specifically, as a deposition and solution process. A blue light emitting compound that can be easily applied can be usefully used in an organic electroluminescent device.

Therefore, when the naphthylphenyl derivative of Formula 1 alone or in combination with a conventional dopant is used as a light emitting material, an organic EL device having excellent luminance and driving voltage characteristics can be manufactured.

The naphthylphenyl derivative represented by Formula 1 of the present invention may be used as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer forming material in addition to the light emitting layer forming material.

In particular, Ar ₁ and Ar ₂ and Ar ₃ of the formula (1) is more preferably a group represented by the formula (2) or 3 independently of each other, particularly preferably a 9-phenylanthracene derivative group represented by the formula (2).

[Formula 2]

(3)

R ₁ to R ₁₆ of Chemical Formula 2 and Chemical Formula 3 are each independently hydrogen; Linear or branched alkyl groups having 1 to 20 carbon atoms; A cycloalkyl group having 5 to 20 carbon atoms; Aryl groups having 6 to 20 carbon atoms; Heteroaryl groups having 4 to 20 carbon atoms; Or at least one substituent selected from a halogen atom, a halogenated alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a heteroaryl group having 4 to 10 carbon atoms It is selected from the group consisting of an aryl group having 6 to 20 carbon atoms, wherein R ₁ , R _{2 ,} R ₃ , R _{4 ,} R _{5 ,} R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R _{13 ,} R _{14 ,} R ₁₅ and R ₁₆ One or more selected may be connected to each other.

As a specific example of the compound represented by the said General formula (1) of this invention, the compound of following formula 1a-1f is mentioned, for example, It is not limited to these.

In Formula 3, R ₁₄ is more preferably a group represented by Formula 4 below.

[Formula 4]

In the above formula, B ₁ , B ₂ , B ₃ , B ₄ , B ₅ are each independently hydrogen; Linear or branched alkyl groups having 1 to 20 carbon atoms; A cycloalkyl group having 5 to 20 carbon atoms; Aryl groups having 6 to 20 carbon atoms; Heteroaryl groups having 4 to 20 carbon atoms; Or a halogen atom; A halogenated alkyl group of 1 to 10 carbon atoms, an alkyl group of 1 to 10 carbon atoms, an alkoxy group of 1 to 10 carbon atoms, an amine group of 1 to 10 carbon atoms, an aryl group of 6 to 10 carbon atoms, or a heteroaryl group of 4 to 10 carbon atoms It is selected from the group consisting of; an aryl group having 6 to 20 carbon atoms having one or more substituents.

The naphthylphenyl derivative represented by the general formula (1) of the present invention is more preferably a compound represented by the general formula (1a) or (1b).

[Formula 1a]

[Chemical Formula 1b]

Hereinafter, an organic electroluminescent device employing a naphthylphenyl derivative represented by Chemical Formula 1 and a manufacturing method thereof will be described.

1 is a view schematically showing a laminated structure of an organic EL device according to an exemplary embodiment of the present invention. Referring to FIG. 1, an emission layer 5 including a naphthylphenyl derivative of Chemical Formula 1 is stacked on the first electrode 3, and a hole suppression layer (HBL) 6 is disposed on the emission layer 5. ), An electron transport layer (ETL), and an electron injection layer (EIL) 7 are stacked, and a second electrode 8 is formed thereon. In the organic EL device of FIG. 1, a hole injection layer (HIL) and a hole transport layer (HTL) 4 are formed between the first electrode 3 and the light emitting layer 5. The organic EL device of FIG. 1 may have a structure in which an electron transport layer (ETL) and an electron injection layer (EIL) 7 are formed on the light emitting layer 5 except for the hole suppression layer (HBL) 6. .

The organic EL device having the above-described laminated structure can be formed by a conventional manufacturing method, and the manufacturing method thereof is not particularly limited.

Hereinafter, a manufacturing method of an organic EL device according to an exemplary embodiment of the present invention will be described.

First, the patterned first electrode 3 is formed on the substrate. Here, the substrate is a substrate used in a conventional organic electroluminescent device, preferably a glass substrate or a transparent plastic substrate excellent in transparency, surface smoothness, ease of handling and waterproof. Specific examples of the substrate include a glass substrate, a polyethylene terephthalate substrate, a polycarbonate substrate, a polyimide substrate, and the like. And the thickness of the substrate is preferably 0.3 to 1.1 mm.

The material for forming the first electrode 3 is not particularly limited. If the first electrode is a cathode, the cathode is made of a conductive metal or an oxide thereof, which is easy to inject holes. As a specific example, indium tin oxide (ITO), indium zinc oxide (IZO), nickel (Ni), Platinum (Pt), gold (Au), iridium (Ir) and the like are used.

After cleaning the substrate on which the first electrode 3 is formed, UV-ozone treatment is performed. At this time, an organic solvent such as isopropanol (IPA) or acetone is used as the washing method.

A hole injection layer 4 is selectively formed on the first electrode 3 of the cleaned substrate. When the hole injection layer 4 is formed in this manner, the contact resistance between the first electrode 3 and the light emitting layer 5 is reduced, and the hole transport capacity of the first electrode 3 with respect to the light emitting layer 5 is improved. The driving voltage and lifetime characteristics of the device can be improved overall. The hole injection layer 4 may be formed of any material that is commonly used. Specific examples thereof include PEDOT {poly (3,4-ethylenedioxythiophene)} / PSS (polystyrene parasulfonate), a starburst material, and copper. Phthalocyanine,

Polythiophene, polyaniline, polyacetylene, polypyrrole, polyphenylene vinylene, or derivatives thereof, m-MTDATA (4,4 ', 4 "- tris [N- (3-methylphenyl) -N-

phenylamino] triphenylamine), and the like. The material is spin coated on the first electrode 3 and then dried to form the hole injection layer 4. Here, the thickness of the hole injection layer 4 is 300-2000 kPa, More preferably, it is 500-1100 kPa. If the thickness of the hole injection layer 4 is out of the above range, it is not preferable because the hole injection characteristics are poor. It is preferable that the said drying temperature is 100-250 degreeC.

The light emitting layer 5 is formed by coating and drying the light emitting layer forming composition on the hole injection layer 4 using a spin coating method or the like. Herein, the light emitting layer forming composition is made of 0.5 to 5% by weight of the naphthylphenyl derivative of Formula 1, which is a light emitting material, and 99.5 to 95% by weight of the solvent. Any solvent can be used as long as it can dissolve the light emitting material, and specific examples thereof include toluene, chlorobenzene, and the like.

In some cases, the light emitting layer forming composition may be mixed with a conventional light emitting material to be used as a light emitting layer. In this case, the content of the light emitting material is variable, but it is preferable that the third light emitting layer forming material is 99.9 to 0.1% by weight based on 0.1 to 99.9% by weight of the naphthylphenyl derivative of the general formula (1).

The conventional light emitting material is not particularly limited but may be polyarylenes or poly (p-phenylene vinylene), and specific examples thereof include poly (9). , 9-dioctyl fluorene) (PC8F), Poly (p-phenylene), MEHPPV (2-Methyloxy-5- (2-ethylhexyloxy) -p-phenylene vinylene).

The film thickness of the light emitting layer 5 is preferably adjusted to be in the range of 100-1000 kPa by adjusting the concentration of the light emitting layer forming composition and the spin speed during spin coating, and more preferably 500-1000 kPa. If the thickness of the light emitting layer 3 is less than 100 mW, the luminous efficiency is lowered. If the thickness of the light emitting layer 3 is more than 1000 mW, the driving voltage is increased, which is not preferable.

A hole transport layer 4 may be selectively formed between the hole injection layer 4 and the light emitting layer 5. Here, the hole transporting film forming material may be used as long as the material satisfies the hole transporting property, and specific examples thereof may include PEDOT, polyaniline, polytriphenylamine, and the like. And it is preferable that the thickness of a hole transport layer is 100-1000 GPa.

The hole suppression layer 6 and / or the electron transport layer 7 are formed on the light emitting layer 5 by using a deposition or spin coating method. Here, the hole suppression layer 6 prevents excitons formed from the light emitting material from moving to the electron transport layer 7 or prevents holes from moving to the electron transport layer 7.

Examples of the material for forming the hole suppression layer 6 include TAZ (3-phenyl-4- (1'-naphthyl) -5-phenyl-1, 2, 4-triazole), BCP (2,9-dimethyl-4, 7-diphenyl-1,10-phenanthroline), LiF, MgF ₂ , phenanthrolines-based compounds (e.g. UDC, BCP), imidazole-based compounds, triazoles-based compounds, oxadiazoles ( oxadiazoles) compounds (eg, PBD), aluminum complex (Aluminum complex) (UDC) BAlq (Aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylpheolate) having the following structural formula is used.

Phenanthroline-containing organic compounds Imidazole-containing organic compounds

Triazole-containing organic compound Oxadiazole-containing compound

BAlq

Examples of the material for forming the electron transport layer (ETL) 7 include an oxazole compound, an isoxazole compound, a triazole compound, an isothiazole compound, an oxadiazole compound, a thiadiazole compound, Perylene-based compounds, aluminum complexes (e.g. Alq3 (tris (8-quinolinolato) -aluminium) , BAlq, SAlq, Almq3), gallium complexes (e.g. Gaq '2OPiv, Gaq' 2 OAc, 2 (Gaq '2)).

 Perylene-Based Compound

        Alq3 BAlq

        SAlq Almq3

     Gaq'2 OPiv Gaq '2 Oac 2 (Gaq'2)

It is preferable that the thickness of the said hole suppression layer 6 is 100-1000 GPa, and the thickness of the said electron carrying layer is 100-1000 GPa. If the thickness of the hole suppression layer and the thickness of the electron transporting layer are outside the above ranges, it is not preferable in terms of electron transport ability or hole suppression ability.

Subsequently, a second electrode 8 is formed on the resultant, and the resultant is sealed to complete an organic EL device.

 The material for forming the second electrode 8 is not particularly limited, and a metal having a small work function, i.e., Li, Ca, Ca / Al, LiF / Ca, LiF / Al, Al, Mg, Mg alloy is used. It is formed by vapor deposition. The thickness of the second electrode 8 is preferably 50 to 3000 mm 3.

The naphthylphenyl derivative of Chemical Formula 1 according to the present invention is used as a light emitting layer forming material when the organic electroluminescent device is manufactured, but can also be used as a hole injection layer or a hole transporting layer forming material.

Hereinafter, a method of manufacturing a naphthylphenyl-based light emitter of the present invention, a light emitting device using the same, and a performance thereof will be described in detail with reference to Examples. The invention will be further illustrated by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

The organic electroluminescent device according to the present invention compensates for the shortcomings of the known low molecules and polymers, and introduces the advantages thereof, so that there are no molecular defects, the thermal stability and crystal stability are excellent, easy to purify, and thin films using It is easy to form.

In addition, improved luminance, driving voltage, and luminous efficiency characteristics are improved.

1 is a view schematically showing a laminated structure of an organic EL device according to an embodiment of the present invention,
2 is a ¹ H-NMR spectrum of a compound represented by Chemical Formula 1a synthesized according to Synthesis Example 1 of the present invention,
3 is a ¹ H-NMR spectrum of the compound represented by Chemical Formula 1b synthesized according to Synthesis Example 2 of the present invention,
4 shows UV-VIS and PL (Photoluminescent) spectra of the compounds represented by Chemical Formulas 1a and 1b synthesized according to Synthesis Examples 1 and 2 of the present invention in a solution state,
Figure 5 shows the UV-VIS, PL (Photoluminescent) spectrum in the film state prepared by spin coating the compound represented by Formula 1a and 1b synthesized according to Synthesis Examples 1 and 2 of the present invention,
FIG. 6 shows a comparison of the compound represented by Chemical Formula 1a synthesized according to Synthesis Example 1 of the present invention with TGA (Thermogravimetric analysis) data of DPVBi, a blue light emitting layer material used in Comparative Example 1,
FIG. 7 is a diagram illustrating the comparison of DSC (Differential Scanning Calorimetry) data of DPVBi, which is a compound represented by Chemical Formula 1a, synthesized according to Synthesis Example 1 of the present invention and a blue light emitting layer material.
8 illustrates EL (electroluminescence) spectra measured using electroluminescent devices fabricated according to Example 1 and Comparative Example 1 of the present invention.
9 is a graph of current density and luminance with respect to voltage measured using the electroluminescent devices manufactured according to Example 1 and Comparative Example 1 of the present invention.

Synthetic example  1: Compound represented by Formula 1a

Scheme 1 below schematically shows a method for preparing a compound represented by Chemical Formula 1a and the following describes a specific embodiment for synthesizing it.

1) Preparation of Compound (1)

5 g (174.8 mmol) of 2,6-dibromonaphthalene were dissolved in anhydrous THF (175 mL). After cooling the mixture to about -78 ° C, 10.93 mL (1.00 eq) of n-butyllithium was slowly added thereto and stirred for 10 minutes. In the reaction mixture, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2-isopropoxy-4,4,5,5-tetramethyl-1,3, 6.75 g (3.5 eq) of 2-dioxabo-rolane) was added and reacted for 1 hour. After the reaction was completed, the mixture was extracted three times using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ , concentrated, and the concentrated solution was n-hexane. Recrystallization using gave 3.78 g (yield: 65%) of compound (1). The structure of compound (1) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.32 (s, 1H), 7.997-7.993 (d, 1H), 7.867-7.844 (q, 1H), 7.755-7.719 (q, 2H), 7.554-7.528 (q, 1 H), 1.387 (s, 12 H).

2) Preparation of Compound (2)

1,3,5-tribromobenzene (1,3,5-tribromobenzene) was dissolved in 244 mL of anhydrous diethylether. After cooling the mixture to about -78 ° C, 20.05 mL (1.01 eq) of n-butyllithium was slowly added thereto and stirred for 10 minutes. 9.68 g (1.2 eq) of iodine was added to the reaction mixture and reacted for 1 hour.

After the reaction was completed, the remaining iodine was extracted twice by using a mixed solvent of aqueous sodium bisulfate solution and diethylether (aqueous solution: diethyl ether = 2: 1 volume ratio). After removing the mixture, the mixture was extracted three times using a mixed solvent of water and diethyl ether (water: diethyl ether = 2: 1 volume ratio). The extracted organic layer was dried over MgSO ₄ , concentrated, and the concentrate was recrystallized with n-hexane to give 9.19 g (yield: 80%) of compound (2). The structure of the compound (2) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 7.730-7.726 (d, 2H), 7.574-7.566 (t, 1H).

3) Preparation of Compound (3)

In a 250 mL round-bottomed flask, 3.50 g (1 eq) of compound (1), 4.93 g (1.3 eq) of compound (2), tetrakistriphenylphosphinepalladium (0) (Pd (pph ₃ ) ₄ ) Add 0.36 g (0.03 mol% vs. compound (1)) and 4.86 mL of aqueous tetraethylammonium hydroxide ((n-Et) ₄ NOH) solution, add 105 mL of anhydrous toluene and 26 mL of anhydrous THF. Was added to dissolve the solid component, and then reacted at 100 ° C. for 12 hours. After completion of the reaction, the mixture was extracted using a mixed solvent of water and chloroform (water: chloroform = 1: 1 by volume), and the extracted organic layer. Was dried over MgSO ₄ . The resulting product was distilled under reduced pressure to remove the organic solvent to obtain a solid, which was dissolved in toluene again, which was first purified using silica gel chromatography, and then recrystallized using n-hexane to give 3.48 g of Compound (3). (Yield = 75%) was obtained. The structure of the compound (3) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.038-8.034 (d, 1H), 7.950 (s, 1H), 7.843-7.821 (d, 1H), 7.778-7.759 (t, 3H), 7.683-7.654 (m, 2 H), 7.616-7.590 (q, 1 H).

 4) Preparation of Compound (4)

9.6 g (37.75 mmol) of 9-phenylanthracene was added to 100 mL of chloroform in a 500 mL round bottom flask, followed by stirring while slowly adding 5.58 g (1.2 eq) of bromine while maintaining 0 ° C. After confirming the disappearance of 9-phenylanthracene (9-phenylanthracene) from the reaction mixture by TLC, bromine addition was stopped and the reaction was stopped. The reaction mixture was extracted twice using an aqueous solution of sodium bisulfate and a mixed solvent of chloroform (aqueous solution: chloroform = 2: 1 volume ratio) to remove residual bromine, and again, a mixed solvent of water and chloroform ( Water: chloroform = 2: 1 volume ratio), and extracted three times. The extracted organic layer was dried over MgSO ₄ , concentrated, and the concentrate was recrystallized with n-hexane to give 10.31 g (yield: 82%) of compound (4). The structure of compound (4) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.624-8.602 (d, 2H), 7.657-7.636 (d, 2H), 7.612-7.547 (m, 5H), 7.417-7.373 (m, 4H).

5) Preparation of Compound (5)

5 g (15 mmol) of Compound (4) was dissolved in anhydrous THF (50 mL) in a 100 mL round bottom flask. After cooling the mixture to about -78 ° C, 14.07 mL (1.5 eq) of n-butyllithium was slowly added thereto and stirred for 10 minutes. 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2-isopropoxy-4,4,5,5-tetramethyl-1,3) was added to the reaction mixture. , 2-dioxaborolane) 4.96 g (3.0 eq) was added to react for 1 hour.

After the reaction was completed, the mixture was extracted three times using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ , concentrated, and the concentrated solution was n-hexane. Recrystallization using gave 3.5 g (yield: 61%) of compound (1). The structure of compound (1) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.442-8.420 (d, 2H), 7.636-7.614 (d, 2H), 7.590-7.521 (m, 3H), 7.488-7.447 (m, 2H), 7.398 -7.374 (m, 2H), 7.333-7.292 (m, 2H), 1.604 (s, 12H).

6) Preparation of the compound represented by Formula 1a

In a nitrogen gas atmosphere, in a 250 mL round bottom flask, 0.9 g (2.0 mmol) of compound (3), 2.6 g (6.5 mmol) of compound (5), tetrakistriphenylphosphinepalladium (0) (Pd (PPh ₃ ) ₄ ) Add 0.07 g (0.05 mol% vs. compound (1)) and 5 mL of tetraethylammonium hydroxide ((n-Et) ₄ NOH) aqueous solution, 100 mL of anhydrous toluene and 25 mL of anhydrous THF. Was added. The temperature of the reaction mixture was raised to about 110 ° C. using an oil bath, and at this temperature the reaction mixture was stirred for about 72 hours.

After the reaction was completed, the mixture was extracted three times using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ . The resulting product was distilled under reduced pressure to remove an organic solvent to obtain a solid, which was separated and purified using silica gel column chromatography using a mixed solvent of n-hexane and chloroform (n-hexane: chloroform = 6: 1). . 1.41 g (yield: about 72%) of the compound represented by Formula 1a were obtained. 2 shows ¹ H-NMR of Chemical Formula 1a.

¹ H-NMR (400 MHz, CDCl 3): δ 8.425 (s, 1H), 8.194-8.169 (d, 6H), 8.117-7.999 (m, 4H), 7.764-7.475 (m, 29H), 7.420-7.382 ( t, 4H), 7.382-7.295 (q, 4H).

Synthetic example  2: compound represented by formula (1b)

Scheme 2 below schematically shows a method for preparing a compound represented by Formula 1b and the following describes a specific embodiment for synthesizing it.

1) Preparation of Compound (6)

5 g (174.8 mmol) of 1,4-dibromonaphthalene were dissolved in anhydrous THF (175 mL). After cooling the mixture to about -78 ° C, 10.93 mL (1.00 eq) of n-butyllithium was slowly added thereto and stirred for 10 minutes. In the reaction mixture, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2-isopropoxy-4,4,5,5-tetramethyl-1,3, 6.75 g (3.5 eq) of 2-dioxabo-rolane) were added and reacted for 1 hour.

After the reaction was completed, the mixture was extracted three times using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ , concentrated, and the concentrated solution was n-hexane. Recrystallization using gave 3.95 g (yield: 68%) of compound (6). The structure of compound (6) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.793-8.760 (m, 1H), 8.299-8.259 (m, 1H), 7.899-7.880 (d, 1H), 7.794-7.775 (d, 1H), 7.606 -7.581 (m, 2H), 1.421 (s, 12H).

2) Preparation of Compound (7)

3.50 g (1 eq) of compound (6), 4.93 g (1.3 eq) of compound (2), tetrakistriphenylphosphinepalladium (0) (Pd (PPh ₃ ) in a 250 mL round-bottomed flask ₄ ) Add 0.36 g (0.03 mol% vs. compound (6)) and 4.86 mL of an aqueous tetraethylammonium hydroxide ((n-Et) ₄ NOH) solution, add 105 mL of anhydrous toluene and 26 mL of anhydrous THF. Was added to dissolve the solid component, and then reacted at 100 ° C. for 35 hours.

After the reaction was completed, the mixture was extracted using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ . The resulting product was distilled under reduced pressure to remove the organic solvent to obtain a solid, which was dissolved in toluene again, which was first purified using silica gel chromatography, and then recrystallized using n-hexane to give 2.95 g of compound (7). (Yield = 63%) was obtained. The structure of compound (7) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.348-8.326 (d, 1H), 7.841-7.822 (d, 1H), 7.788-7.755 (q, 2H), 7.663-7.622 (m, 1H), 7.562 -7.521 (m, 3 H), 7.234-7.215 (d, 1 H).

3) Preparation of Compound (8)

In a nitrogen gas atmosphere, in a 100 mL round bottom flask, 2.00 g (4.54 mmol), 4,4,4 ', 4', 5,5,5'-octamethyl-2,2'-di (7) 1,3,2-dioxaborolane) (4,4,4 ', 4', 5,5,5 ', 5'-octamethyl-2,2'-di (1,3,2-dioxaborolane) 3.30 g (3.3 eq), [1,1'-bis (diphenylphosphino) ferrocene] dichloropalladium (II) (Pd (dppf) Cl ₂ ) 0.33 g (4.5x 10 ^-4 mol), and potassium acetate (KOAc ) 4.45 g (10.0 eq) and 45 mL of anhydrous 1,4-dioxane were added in. The temperature of the reaction mixture was raised to 100 ° C. using an oil bath and stirred for 12 h. After the reaction was completed, the mixture was extracted using a mixed solvent of water and chloroform (water: chloroform = 1: 1 by volume), and the extracted organic layer was dried over MgSO _4. The resultant was distilled under reduced pressure to remove the organic solvent. To obtain a solid, which was dissolved in toluene again, and then using silica gel chromatography. After primary purification, recrystallization with n-hexane gave 0.8 g (yield = 30%) of compound (8) The structure of compound (8) was confirmed by ¹ H-NMR.

¹ H-NMR (400 MHz, CDCl ₃ ): δ 8.832-8.811 (d, 1H), 8.336 (s, 1H), 8.089-8.071 (d, 1H), 7.990-7.987 (d, 2H), 7.809-7.788 (d, 1H), 7.537-7.496 (m, 1H), 7.417-7.376 (m, 2H), 1.446 (s, 12H), 1.340 (s, 24H).

4) Preparation of the compound represented by Formula 1b

Under a nitrogen gas atmosphere, 0.8 g (4.54 mmol) of Compound (8), 1.6 g (3.5 eq) of Compound (4), Pd (PPh- ₃ ) ₄ 0.08 g (0.7 × 10 ⁻ ) in a 100 mL round bottom flask ⁴ mol), 1.91 mL (3.3 eq) of (n-Et) NOH, 46 mL of anhydrous toluene and 12 mL of anhydrous THF were added. The temperature of the reaction mixture was raised to about 100 ° C. using an oil bath and then stirred for 48 hours. After the reaction was completed, the mixture was extracted three times using a mixed solvent of water and chloroform (water: chloroform = 1: 1 volume ratio), and the extracted organic layer was dried over MgSO ₄ . The resultant was distilled under reduced pressure to remove an organic solvent to obtain a solid, which was separated and purified using silica gel column chromatography using a mixed solvent of n-hexane and chloroform (n-hexane: chloroform = 6: 1). . 0.22 g (yield: about 17%) of the compound represented by Chemical Formula 1b was obtained. 3 shows ¹ H-NMR of Chemical Formula 1b.

¹ H-NMR (400 MHz, CD ₂ Cl ₂ ): δ 8.593-8.572 (d, 1H), 8.285-8.263 (d, 4H), 8.084-8.080 (d, 2H), 8.023-8.005 (d, 1H) , 7.801-7.794 (t, 1H), 7.746-7.724 (d, 6H), 7.693-7.469 (m, 25H), 7.433-7.392 (m, 4H), 7.340-7.298 (m, 2H), 7.272-7.203 ( m, 4H).

Measurement of physical properties

The compounds represented by Formulas 1a and 1b prepared according to the synthesis example were dissolved in chlorobenzene, the solution was spin coated on a quartz substrate, and then dried to form a thin film.

The UV-VIS spectrum and PL (photoluminescence) spectrum of the thin film obtained by the above procedure were measured, and the results are shown in FIG. 5. Referring to FIG. 5, the positions of the maximum UV-VIS absorption peaks of the compound represented by Chemical Formula 1a showed three characteristic peaks at 362 nm, 381 nm, and 402 nm, respectively. The location of the largest PL peak measured was approximately 435 nm. In addition, the thermal properties of the compound represented by Formula 1a prepared according to the synthesis example by using TGA (Thermogravimetric analysis) and DSC (Differential Scanning Calorimetry) were examined. At this time, the thermal characteristics were measured at a rate of 10 ° C./min under a nitrogen gas atmosphere. The TGA and DSC measurement results are shown in FIGS. 6 and 7, respectively. In FIG. 6, Chemical Formula 1a is for the compound represented by Chemical Formula 1a prepared in Synthesis Example, and the chemical formula 5 is named DPVBi [4,4 'bis (2,2) which is generally compared with a blue light emitting material. diphenylvinyl) -1,1 'biphenyl]. Referring to FIG. 6, DPVBi had a weight loss of about 5% at about 362 ° C., and a residual amount of about 50% by weight at about 440 ° C. On the other hand, in the case of the compound represented by Formula 1a, a weight loss of 5% was observed at about 525 ° C., and showed excellent thermal stability showing a residual amount of about 77% by weight at around 600 ° C. On the other hand, with reference to Figure 7, while showing a distinct melting point observed in most of the low-molecular electroluminescent materials (although it shows a distinct melting point even after melting and re-cooling fast), the compound represented by Formula 1a is 350 No melting phenomenon was observed during heating to ℃. This means that the compound represented by the formula (1a) is thermally very stable and is in a completely amorphous state. In addition, when the thin film was prepared using spin coating and the surface thereof was observed through a polarizing microscope, no crystal region was found in the thin film.

Example  1: organic Field  Fabrication of light emitting device

2-TNATA [4,4,4'-Tris], a composition for forming a hole injection layer, using a vacuum evaporator on a transparent electrode substrate patterned with indium-tin oxide (ITO) (with a vacuum degree of 4 × 10 ^-6 torr or less) (N- (2-naphthyl) -N-phenyl-amino) -tripenylamine] and α-NPB [N, N'-bis (naphthalene-1-yl) -N, N'-diphenylbenzidine], a composition for forming a hole transport layer Were sequentially deposited to a thickness of 600 kPa and 150 kPa, respectively, and a compound of Formula 1a, a light emitting layer forming composition prepared according to Synthesis Example 1, was formed on the hole transport layer to a thickness of 300 kPa. Subsequently, Alq ₃ , LiF, and Al were sequentially deposited on the emission layer to form a cathode having a thickness of 2500˜3000 μm, and encapsulation thereof to complete an organic EL device. In the deposition process, the film thickness and the growth rate of the film were controlled by using a crystal sensor. The schematic structure of the EL device thus fabricated is as shown in FIG. 1, and the stacked device structure is ITO / 2-TNATA (600 kV) / NPB (150 kV) / Formula 1a (300 kV) / Alq3 ( 300 Å) / LiF (10 Å) / Al (2000 Å) and the emission area was 6 mm ² . As physical properties of the fabricated device, FIG. 8 shows EL spectra, FIG. 9 shows current density and brightness, and Table 1 records luminous efficiency, brightness, driving voltage, and color coordinate data. Was commercially is significantly lower than 2 V Turn-on voltage compared to DPVBi also improve efficiency in use was what improved half-life in the life of the device, 500 cd / m ^2, more than 1.5 times the case of using the formula (1a) as a light emitting layer.

Example  2: Organic Field  Fabrication of light emitting device

The device was manufactured in the same manner as in Example 1, except that Chemical Formula 1b was used as the emission layer. The stacked device structure is composed of ITO / 2-TNATA (600 Å) / NPB (150 Å) / Formula 1b (300 Å) / Alq3 (300 Å) / LiF (10 Å) / Al (2000) Iii) and the emission area was 6 mm ² . Table 1 records the luminous efficiency, luminance, driving voltage, and color coordinate data. In the case of using the formula 1b as a light emitting layer, in this embodiment, the turn-on voltage is lowered by 1 V or more and the efficiency is also improved by 30% or more compared with the DPVBi which is commercially used. The lifetime of the device is half life at 500 cd / m ² , 1.2. Improvements over 2x.

Example  3: organic Field  Fabrication of light emitting device

PEDOT (poly (styrene sulfonate) -doped poly (3,4-ethylenedioxy thiophene: Batron P 4083 from Bayer) was coated with a thickness of about 400in on a transparent electrode substrate patterned with indium-tin oxide (ITO), followed by 180 ° C At about 1 hour to form a hole injection layer. A light emitting layer-forming composition obtained by dissolving 0.15 g of the compound of Formula 1a prepared according to Synthesis Example 1 in 9.85 g of chlorobenzene on the hole injection layer. Was spin coated on the hole injection layer, baked for 2 hours at 90 ° C., and then completely removed in a vacuum oven to form a light emitting layer having a thickness of 500 Å. The organic electroluminescent device is fabricated by sequentially depositing TPBi, LiF and Al while forming vacuum and encapsulating the cathode by encapsulating the TPBi, LiF and Al while maintaining the vacuum degree below 4 × 10 ^-6 torr using a vacuum evaporator. The film thickness and growth rate of the LiF and Al deposition were controlled by using a crystal sensor.The structure of the EL device fabricated as described above was ITO / PEDOT: PSS (400 kV) / Formula 1a ( 500 Å) / TPBi (300 Å) / LiF (10 Å) / Al (2000 Å) and the emission area was 6 mm ^{2. The} important point is that the formula 1a can be easily manufactured by spin coating method, not by evaporation. The result of the obtained device was also nearly equivalent to that of the deposition, which is shown in Table 1.

Example  4: organic Field  Fabrication of light emitting device

The device was manufactured in the same manner as in Example 3, except that Chemical Formula 1b was used as the light emitting layer. 10 shows data of current density, luminance, luminous efficiency, driving voltage, and color coordinates according to the present invention. In the same manner as in Example 3, Chemical Formula 1b could be easily manufactured by spin coating instead of deposition as a light emitting layer, and the result of the obtained device was also nearly equivalent to that of deposition. In addition, the operating voltage also showed a better result of 2 V than the phase deposition. Specific results are shown in Table 1.

Comparative example  1: organic Field  Fabrication of light emitting device

DPVBi [4,4'-bis (2,2-diphenylvinyl) as a comparative material in place of the compound of Formula 1a prepared in Synthesis Example 1 using the same lamination structure as the vacuum deposition condition as in the method prepared in Example 1 ) biphenyl] was used to fabricate an organic EL device. The structure of DPVBi used as a comparative material as a blue light emitting material in the organic EL device is represented by the following Chemical Formula 5.

[Chemical Formula 5]

             DPVBi

The EL spectra measured from Example 1 and Comparative Example 1 are shown in FIG. 8. In addition, luminous efficiency was calculated using luminance, current density, and voltage. The calculated luminous efficiency of the organic photoelectric device is shown in Table 1 below. In addition, luminance, driving voltage and color coordinates are also shown in Table 1 below, and FIG. 8 shows the EL spectrum.

Emitting material Production Process Current density
(mA / cm ² ) Luminance
(cd / m ² ) Driving voltage
(V) Luminous efficiency
(lm / W) Color coordinates
(x, y) Example 1 Formula 1a deposition 10 383 6.6 1.82 0.177, 0.181 Example 2 1b deposition 10 395 7.5 1.65 0.194, 0.184 Example 3 Formula 1a Spin coating 10 297 5.4 1.73 0.178, 0.181 Example 4 1b Spin coating 10 290 5.7 1.60 0.193, 0.182 Comparative Example 1 DPVBi deposition 10 345 8.6 1.26 0.151, 0.166

As described in detail above, the naphthylphenyl derivative of the present invention has a structure having a naphthylphenyl unit as the center structure and an aromatic is introduced at positions 2 and 3 and 5 of naphthyl of the naphthylphenyl unit. As a blue light-emitting compound having a good thermal stability and crystal stability, easy to purify, it is easy to form a thin film using a soluble solvent. In addition, the naphthylphenyl derivative of the present invention is not only capable of manufacturing a device through a deposition process, but also capable of manufacturing an organic electroluminescent device through a solution process. Using the blue light emitting compound, an organic EL device having improved luminance, driving voltage, and luminous efficiency may be manufactured.

Claims (6)

Naphthylphenyl derivative represented by the following formula (1):
[Formula 1]

In the above formula, Ar ₁ , Ar ₂ and Ar ₃ are represented by the following formula (2) irrespective of each other.
(2)

R ₁ to R ₁₃ in Formula 2 may be independently selected from hydrogen; Linear or branched alkyl groups having 1 to 20 carbon atoms; A cycloalkyl group having 5 to 20 carbon atoms; Aryl groups having 6 to 20 carbon atoms; Heteroaryl groups having 4 to 20 carbon atoms; Or halogen atom, halogenated alkyl group of 1 to 10 carbon atoms, alkyl group of 1 to 10 carbon atoms, alkoxy group of 1 to 10 carbon atoms, amine group of 1 to 10 carbon atoms, aryl group of 6 to 10 carbon atoms, heteroaryl of 4 to 10 carbon atoms It is selected from the group consisting of; an aryl group having 6 to 20 carbon atoms having one or more substituents selected from the group.
delete delete An organic electroluminescent device comprising an organic film between a pair of electrodes,
The organic electroluminescent device comprising the naphthylphenyl derivative according to claim 1.
The organic electroluminescent device according to claim 4, wherein the organic film is a light emitting layer, a hole injection layer, a hole transport layer, an electron injection and an electron transport layer.
The method of claim 5,
The organic film is a light emitting layer;
And the light emitting layer comprises 0.1 to 99.9% by weight of naphthylphenyl derivative and 99.9 to 0.1% by weight of a light emitting material.

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