KR101610235B1 - Metal complex containing phenyl-pyridines connected to carbazoles, it's preparation method and it's applications - Google Patents

Abstract

The present invention relates to phenyl-pyridine-based metal complexes linked with a carbazole structure represented by formula (1). Exhibit high electroluminescence (EL) intensities at 481 nm to 486 nm and are thus more suitable for use in blue organic light emitting diodes than phenyl-pyridine based metal complexes that do not include carbazole structures. In addition, it can be applied as a white light source for lighting by adjusting the size of electroluminescence (EL) peak at about 620 nm, and it is possible to use one primary color (sky-blue, orange-red) or three primary colors (red, green and blue) It is suitable for the use of white organic light emitting diodes using only materials.

Formula 1

Carbazole, phenylpyridine, luminescent material, diode, OLED, sensor material, organic metal, dendrimer

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal complex containing a phenylpyridine structure connected to a carbazole group,

The most widely used liquid crystal display (LCD) is a non-light emitting type display device, which consumes less power and is light in weight. However, the device driving system is complicated and response characteristics such as response time and contrast are not satisfactory. Therefore, research on an organic electroluminescence device, which has recently attracted attention as a next-generation flat panel display, has been actively conducted. The organic light emitting device is a self-light emitting type device having various characteristics such as luminance, driving voltage and response speed, and is not dependent on viewing angle, compared with a liquid crystal display.

The emission mechanism of the organic EL device will be described below. The holes injected from the anode to the HOMO of the hole injection layer HIL travel through the hole transport layer HTL to the light emitting layer EML and electrons move from the cathode to the light emitting layer through the electron injection layer EIL And is combined with holes to form an exciton. This exciton emits light as it falls to the ground state.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material used for an organic light emitting diode (OLED) which can be used for illumination, sensors and the like, which emits light by electric energy and is used for display applications.

In 1987, Eastman Kodak Company developed an electroluminescent device using TPD as a hole transport layer and Alq ₃ as a light emitting layer using the principle of organic EL devices (Appl, Phys. Lett., 51, 913, 1987). Thereafter, research on an electroluminescent device using an organic material is actively conducted. In recent years, commercialization of display and illumination components based on organic light emitting diodes (OLEDs) is underway. This development was initiated by an important invention disclosed in EP 423 283 (WO 90/13148).

In recent years, Samsung Electronics and LG Electronics have introduced OLED mobile phones. Samsung SDI has produced 40-inch full HD TVs and 4-inch flapping displays as prototypes. At CES 2009, LG Electronics exhibited 15-inch AMOLED TV, digital picture frames with OLEDs from Samsung Electronics and Kodak, and 5-inch AMOLED portable mobile Internet devices from OQO. Sony also exhibited flexible OLED OLED, Sony Walkman with full touch screen, and AMOLED TV with thickness of about 0.9mm.

Organic light emitting diodes have several advantages over devices using inorganic materials. The organic compound is easily dissolved in an organic solvent to lower the production cost and the wavelength of the emitted light can be easily adjusted by mixing with other organic compounds.

Organic light emitting diodes can be used in applications such as flat panel displays, illumination, and backlighting by emitting light when current is supplied.

An object of the present invention is to provide a phenyl-pyridine-based metal complex having a very high electroluminescence (EL) intensity in the range of 481 nm to 486 nm and thus having a carbazole structure that can be used for a blue organic light emitting diode.

The present invention also aims at providing a method for producing a metal complex. Further, the present invention aims to provide a light emitting device having an extremely high efficiency at 7.5 cd / A and 3.9 lm / W in the 481 nm to 486 nm region by incorporating the metal complex compound in the light emitting layer.

Another object of the present invention is to provide a light emitting device which can be used as a white light source for illumination by adjusting a light emitting region at about 620 nm by incorporating a metal complex compound in a light emitting layer.

In a preferred embodiment of the present invention, a phenylpyridine-based metal complex having a carbazole structure is synthesized, and the light emitting layer of the light emitting device is partially or wholly used to have a high electroluminescence intensity at 481 nm or 486 nm and a maximum efficiency of 7.5 cd / A and 3.9 lm / W is provided.

The present invention provides a white light emitting device for illumination capable of being applied as a white light source for illumination with a single material by adjusting a light emitting region at about 620 nm by including a metal complex compound in a light emitting layer.

The metal complexes prepared according to the present invention have very high electroluminescence (EL) intensities at 481 nm to 486 nm and can be used as blue light emitting organic light emitting diodes at a maximum efficiency of 7.5 cd / A and 3.9 lm / W.

The metal complex prepared according to the present invention exhibits the intrinsic luminescence characteristics of a material other than the peak due to eximer formation due to the increase of the electroluminescence intensity in the region of about 620 nm in accordance with the concentration of the dopant and the metal complex is used as a white light source for illumination And can be used as a single material in organic light emitting diodes.

Generally, an organic light emitting diode includes at least one organic layer between an anode and a cathode. When current is supplied, the positive electrode injects holes and the negative electrode injects electrons. When holes and electrons meet in one molecule, excitons are formed in the molecules. Light is emitted when the exciton is relaxed via the light emission mechanism.

Excitons of organic light emitting diodes are produced with 75% triplet and 25% singlet, and phosphorescent organic light emitting diodes can theoretically achieve 100% internal quantum efficiency. Organic light emitting diodes using phosphorescent compounds emitted from a triplet excited state are disclosed in U.S. Patent No. 6,303,238.

Korean Patent Application No. 10-2005-7002654 discloses various phenylpyridine-based metal complexes. According to claims 57 and 58 of the aforementioned patent, the emitted light has the highest emission intensity at 520 nm or less, A light emitting device having a wavelength of about 480 nm is claimed but does not mention electroluminescence at about 620 nm.

In addition, in reference to literature related to the conventional phenylpyridine-based iridium complexes, Korea Patent Application No. 10-2005-7003257 discloses a method for preparing a complex represented by Fac tris [4- {3 ', 5'-di [4 " 2 '''' - {3 ''''',5''''- di [4' Phenyl)} phenyl) -pyridine] iridium (III), which has an emission peak at about 540 nm and an emission intensity at 620 nm Very low.

Korean Patent Publication No. 10-2005-7017798 discloses an electroluminescence spectrum of various phenylpyrazole-based iridium complexes, and the emission at about 620 nm region is weak.

As shown in FIG. 3, the phenyl-pyridine-based metal complexes connected to the carbazole structure provided by the present invention show high emission intensities at about 486 nm and 620 nm.

In general, the white light source for illumination is manufactured using the primary colors (sky-blue, orange-red) and the three primary colors (red, green and blue), but the metal complexes developed in the present invention are not peaks due to eximer formation, As the concentration of dopant increases, the size of the electroluminescence peak becomes larger as the concentration of dopant increases. Therefore, it can be used as a white light source as a single material and can be used as a white light source for illumination at a low processing cost through simplification of the process.

Preferred ancillary ligands include acetylacetonate (acac), picolinate (pic) dipivaloylmetanate (t-butyl acac). Additional non-limiting examples of ancillary ligands can be found in application publication WO 02/15545 A1, Lamansky et al.

The present invention provides, in a preferred embodiment, a method for synthesizing a metal complex. Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples. These embodiments are only for illustrating the present invention, and the scope of the present invention is not limited by these examples.

Example 1

Preparation of intermediate compounds:

Synthesis of Compound (1)

(300 mL) was added to 4-bromophenol (30.0 g, 0.17 mol), 2-ethylhexyl bromide (23.2 g, 0.12 mol), KOH (11.5 g, 0.20 mol) and NaI Lt; / RTI > The temperature was lowered to room temperature, the solvent was removed, water was poured into the reaction and extracted with hexane. The organic layer containing the product is removed with water using MgSO ₄ and the solvent is removed. A liquid compound was obtained using a silica column (Hexane). (40.6 g, 82%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 7.36 (d, 2H), 6.93 (d, 2H), 4.12 (m, 1H), 1.35 (m, 2H), 1.31 (m, 4H), 0.98 ( m, 6H)

 Synthesis of Compound (2)

(6.1 g, 57.40 mmol), 18-crown-6 (1.9 g, 4.78 mmol), K ₂ CO ₃ (26.4 g, 191.3 mmol) and the compound (1) (15.0 g, 52.60 mmol) carbazole (7.5 g, 44.80 mmol) in dichlorobenzene (150 mL) and reflux for 32 h. The temperature is lowered to room temperature, the solids are filtered off and the solvent is removed by vacuum distillation. Silica column (DCM: Hexane = 5: 1, v / v) was used to obtain an oil phase compound. (11.7 g, 60%); ¹ H NMR (300 MHz, CDCl ₃ ,?): 8.22-8.19 (m, 2H), 7.40 (d, 2H), 7.20-7.08 ), 1.29 (m, 4H), 0.96 (m, 6H)

Synthesis of compound (3)

2-bromo-1,3-difluorobenzene ( 10.0 g, 51.82 mmol) _{and, CF 3 SO 3 H (9.3} g, 61.20 mmol), 1,3-dibromo-5,5-dimethylhydantoin (8.9 g, 31.10 mmol) to Add CH2Cl2 (80 mL) and stir at room temperature for 2 hours. To terminate the reaction, saturated sodium hydrogensulfite solution is added to the reaction and neutralized with 2 M sodium carbonate solution. The organic layer was separated, and water was removed using MgSO ₄ and the solvent was removed. A liquid compound was obtained using a silica column (Hexane). (10.2 g, 73%); ¹ H NMR (300 MHz, CDCl ₃ ,?): 7.74 (m, 1 H), 6.92

 Synthesis of Compound (4)

Compound (3) (7.0 g, 25.70 mmol), 2-tributylstannyl pyridine (9.3 g, 25.70 mmol) and Pd (PPh ₃ ) ₄ (1.4 g, 1.31 mmol) were placed in anhydrous toluene Reflux for 12 hours. The temperature is lowered to room temperature, then the solvent is removed and extracted with DCM. The organic layer was separated, and the water was removed using MgSO ₄ , and then the solvent was removed. A white compound was obtained using a silica column (EtOAc: hexane = 1: 10, v / v). (6.6 g, 95%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 8.50 (s, 1H), 7.89 (t, 1H), 7.54 (d, 1H), 7.38 (d, 1H), 7.04 (d, 1H), 6.82 ( t, 1 H)

Synthesis of compound (5)

2,5-dibromo-p-xylene (25.0 g, 94.71 mmol) was added to diethylether (350 mL) under nitrogen flow, the temperature was lowered to -78 ° C and 2.5 M n-BuLi (31.5 g, 113.6 mmol) do. After the temperature was raised to room temperature, the mixture was stirred for 1 hour, and DMF (8.3 g, 113.65 mmol) was slowly added thereto at -78 ° C, followed by stirring at room temperature for 12 hours. To terminate the reaction, the reaction mixture is poured into water and extracted with diethylether. The organic layer was washed with MgSO ₄ to remove water and the solvent was removed. A white solid was obtained using a silica column (Hexane). (15.6 g, 71%); ¹ H NMR (300 MHz, CDCl ₃ ,?): 10.12 (s, IH), 7.38 (s, IH), 7.30

Synthesis of Compound (6)

(4.3 g, 20.20 mmol), bis (pinacolato) diboron (6.7 g, 26.20 mmol), potassium acetate (4.2 g, 42.80 mmol) and [1,1'- bis (diphenylphosphino) ferrocene ] dichloropalladium (0.8 g, 5 mol%) were dissolved in DMSO (40 mL) and stirred at 80 ° C for 16 hours. After completion of the reaction, the reaction mixture was extracted with diethylether, and then the organic layer was washed with MgSO ₄ to remove water and the solvent was removed. Silica column (EtOAc: Hexane = 3: 1, v / v)) was used to obtain a white solid. (5.1 g, 84%); ¹ H NMR (300 MHz, CDCl ₃ ,?): 10.27 (s, 1H), 7.64 (s, 1H), 7.58 (s, s, 12H)

Synthesis of Compound (7)

Compound 4 (3.5 g, 13.00 mmol), compound 6 (4.4 g, 16.85 mmol) and Pd (PPh ₃ ) ₄ were added to potassium carbonate aqueous solution (2 M, 10 mL) and THF (30 mL) 0.0 > C < / RTI > for 72 hours. After the temperature is lowered to room temperature, water is added and the mixture is extracted with diethylether. The organic layer is dried with MgSO ₄ to remove water and the solvent is removed. Silica column (EtOAc: Hexane = 1: 10, v / v)) was used to obtain a white solid. (2.5 g, 60%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 10.31 (s, 1H), 8.78 (d, 1H), 8.02 (dd, 1H), 7.77 (d, 3H), 7.30-7.13 (m, 3H), 2.69 (s, 3H), 2.67 (s, 3H)

Synthesis of Compound (8)

Compound (2) (5.2 g, 13.60 mmol) and compound (7) (2.0 g, 6.81 mmol) were dissolved in glacial acetic acid (50 mL), conc. HCl (5 mL), and the mixture is stirred at 90 占 폚 for 30 hours. After the temperature is lowered to room temperature, water is added and the mixture is extracted with diethylether. The organic layer is dried with MgSO ₄ to remove water and the solvent is removed. Silica column (DCM: Hexane = 3: 1, v / v)) was used to obtain a white solid. (3.8 g, 59%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 8.71 (d, 1H), 8.05 (d, 2H), 8.02 (dd, 1H), 7.83 (s, 2H), 7.75 (d, 3H), 7.49 ( (m, 2H), 7.37 (d, 4H), 7.37-7.06 (m, 18H), 6.83 , 1.57-1.39 (m, 16H), 1.37-0.94 (m, 12H)

Synthesis of iridium complex

A) Ir (III) -μ-chloro-bridged dimer (compound (9))

2-ethoxyethanol (15 mL) and put to _{IrCl 3 · nH 2 O (0.3} g, 0.72 mmol) and compound (8) (2.0 g, 1.45 mmol) in a mixed solvent of water (5 mL) under a stream of nitrogen 120 ^o C < / RTI > for 20 hours. After the reaction, the orange colored solution is poured into water (200 mL), precipitated, washed with ethanol and hexane, and dried. The dried material is Ir (III) -μ-chloro-bridged dimer (2.2 g, 75%).

B) an iridium complex containing only the main ligand (compound (11))

In Tetraethylene glydcol (20mL) into the dimer (1.0 g, 0.25 mmol) and compound (8) (0.6 g, 0.61 mmol) Na 2 CO 3 (0.3 g, 2.50 mmol) and stirred for 24 hours in a nitrogen stream 190 ^o C . After the temperature is lowered to room temperature, the reaction product is poured into water (200 mL), precipitated, filtered, washed with water, and the solvent is removed. A yellow solid was obtained using a silica column (DCM: Hexane = 9: 1, v / v). (0.34 g 48%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 8.53 (d, 1H), 7.99 (d, 2H), 7.83 (s, 2H), 7.75 (d, 3H), 7.49 (d, 4H), 7.37- 2H), 1.57-1.39 (m, 2H), 7.06 (m, 18H), 6.78 (s, 16H), 1.37-0.94 (m, 12H)

(R: ethyl hexyl)

Example 2

The iridium complex (compound 10) containing ancillary ligands

In 2-ethoxyethanol (25mL) dimer (1.0 g, 0.25 mmol) the dissolved 2-picolinic acid (0.07 g, 0.61 mmol) and _{Na 2 CO 3 (0.3 g,} 2.50 mmol) a in mixture, and a nitrogen stream 120 ^o C Stir for 24 hours. After the temperature is lowered to room temperature, the reaction product is poured into water (200 mL), precipitated, filtered, washed with water, and the solvent is removed. Silica column (EtOAc: Hexane = 30: 1, v / v) was used to obtain a yellow solid. (0.27 g 52%); ^{1 H NMR (300 MHz, CDCl} 3, δ): 8.74 (d, 2H), 8.52 (d, 2H), 8.13 (d, 2H), 8.02 (dd, 2H), 7.83 (s, 2H), 7.75 ( (d, 8H), 7.49 (d, 8H), 7.37-7.06 (m, 36H), 6.73 (s, d, 12H), 1.79-1.81 (m, 4H), 1.54-1.37 (m, 32H), 1.35-0.92

(R: ethyl hexyl)

Example 3

In order to investigate the electroluminescence characteristics of the two iridium complexes (Formula 2 and Formula 3), hole injection and PEPOT as a hole transport layer were spin-coated on a substrate having an ITO electrode formed on a glass substrate, The blue phosphorescent metal dendrimers were spin-coated to form a light emitting layer having a thickness of 40 nm. BCP, Alq ₃ , and LiF were vacuum evaporated to form the hole blocking layer, the electron transport layer and the electron injection layer, respectively, and their luminescent characteristics were measured. The device structure is composed of ITO / PEPOT (40 nm) / PVK: dopant (40 nm) / BCP (10 nm) / Alq ₃ (40 nm) / LiF 2) was prepared.

  Figure 1 relates to phenyl-pyridine-based metal complexes linked to a carbazole structure.

  2 shows a light-emitting device manufactured by using the compound synthesized in Examples 1 and 2 as an EML layer.

 Fig. 3 shows an electroluminescence spectrum of the compound (Homoleptic) synthesized in Example 1 measured on the luminescent layer of the device shown in Fig. 2 by changing the concentration without changing the thickness.

Fig. 4 shows the luminescence efficiency spectrum of the compound (Homoleptic) synthesized in Example 1 measured on the luminescent layer of the device shown in Fig. 2 by changing the concentration without changing the thickness.

 5 shows the electroluminescence spectrum of the compound (Heteroletpic) synthesized in Example 2 measured on the luminescent layer of the device shown in Fig. 2 by changing the concentration without changing the thickness.

6 shows the luminescence efficiency spectrum of the compound (Heteroletpic) synthesized in Example 2 measured on the luminescent layer of the device shown in Fig.

FIG. 7 shows the production reaction of a first generation iridium dendrimer containing at least one kind of dendron . (Examples 1 and 2)

Claims (4)

 A metal complex compound represented by the following formula (2) or (3). (2)

In formula (2) R is 2-ethylhexyl, (3)

In formula (3) R is 2-ethylhexyl. delete A light emitting device using an organic layer comprising a metal complex represented by the following Chemical Formula 2 or 3 (2)

In formula (2) R is 2-ethylhexyl, (3)

In formula (3) R is 2-ethylhexyl. delete

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