KR101503767B1 - The new metal complex and blue phosphorescent organic light emitting device comprising the same - Google Patents

Abstract

The present invention relates to a novel metal complex compound and a blue phosphorescent organic light emitting device comprising the same. The present invention provides a metal complex compound represented by a specific formula and a blue phosphorescent organic light emitting device comprising the same, and has an excellent luminescent color coordinate and an excellent long life characteristic since it has an ancillary ligand of a rigid structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a novel metal complex and a blue phosphorescent organic light emitting device including the same. BACKGROUND ART [0002]

The present invention relates to a novel metal complex compound and a blue phosphorescent organic electroluminescent device including the same, and more particularly, to a phosphorescent organic electroluminescent device having a blue phosphorescent organic electroluminescent device having only a ligand having a wide band gap of phenylpyridine structure, and a blue phosphorescent organic electroluminescent device including the novel metal complex, wherein the blue phosphorescent organic electroluminescent device comprises the phosphorescent dopant.

Background Art Organic light emitting devices (OLEDs), which receive the spotlight as a next generation display, are actively and academically studied in various fields such as electricity, electronics, materials, chemistry, physics and optics. In recent years, OLEDs have been widely used in PDAs, mobile phones, game machines, and the like. [0004] In recent years, organic light emitting devices (OLEDs) Research and commercialization for application to mobile displays is underway.

In addition, it has been known that not only fluorescent materials but also phosphorescent materials can be used as organic light emitting devices (OLEDs). Phosphorescent luminescence is a phenomenon in which electrons are transferred from ground states to excited states, and then single-excitons are non-luminescent transitioned to triplet excitons through intersystem crossing, and then triple excitons And a light emitting mechanism. This phosphorescence emission can not transfer to the ground state when the triplet exciton is transited, and the lifetime (luminescence time) of the phosphorescence is longer than that of fluorescence because the phosphorescence is transferred to the bottom state after the reversal of the electron spin proceeds. That is, the emission duration of fluorescence emission is only several nanoseconds, but in the case of phosphorescence emission, it corresponds to a relatively long time of several microseconds.

In general, the phosphorescent organic light emitting device (PHOLED) includes an anode made of an ITO transparent electrode; A hole transport layer (HTL) formed on the anode; An emission layer (EML) formed on the hole transport layer (HTL); An electron transport layer (ETL) formed on the emission layer (EML); And a cathode formed on the electron transport layer (ETL), which are successively laminated on the substrate through a method such as vapor deposition. The light emitting layer (EML) includes a host as a charge transporting material and a dopant as a phosphorescent material.

When a voltage is applied to the phosphorescent organic light emitting device (PhOLED) having the above structure, holes are injected from the anode and electrons are injected from the cathode. The injected holes and electrons are injected through the hole transport layer (HTL) and the electron transport layer (EML) to form luminescent excitons. Then, the formed luminescent excitons emit light while transitioning to the bottom state.

In recent years, efforts have been made to increase the luminous efficiency of the phosphorescent organic light emitting device (PhOLED). As a result, a technique having a high luminous efficiency of 29% for green and 15% for red has been reported. However, blue light has a poor luminous efficiency, color coordinate characteristic and longevity compared to green and red. A lot of researches are going on to solve this problem. Mainly, the improvement of the layer structure of the device and the research on the new material of the host and the dopant are proceeding.

First, Korean Patent Laid-Open No. 10-2007-0091291 discloses an organic light emitting device using as a host a substance containing a triarylamine group in relation to a host of a light emitting layer (EML). Korean Patent Laid- 0041952 discloses a carbazole compound represented by a specific formula.

On the other hand, metal complexes are useful as dopants constituting the light-emitting layer (EML).

In recent years, studies have been made on such dopants. For example, Korean Patent Laid-Open No. 10-2010-0061831 discloses a technique for a metal complex as a dopant.

However, conventional metal complexes used as dopants, that is, blue phosphors according to the prior art, have low stability, and conventional blue phosphorescent organic light emitting devices (PhOLEDs) using the same have a short life, The life span is insufficient and causes many problems in practical application.

Korean Patent Publication No. 10-2007-0091291 Korean Patent Publication No. 10-2011-0041952 Korean Patent Publication No. 10-2010-0061831

Accordingly, it is an object of the present invention to provide a novel metal complex compound and a blue phosphorescent organic electroluminescent device (PhOLED) containing the ligand, which can provide excellent color coordinates, especially long life characteristics, when a novel metal complex having only a specific structure is used. The purpose is to provide.

It is another object of the present invention to provide a novel blue phosphorescent organic electroluminescent device in which luminance is maintained for a long time.

In order to accomplish the above object, the present invention provides a metal complex compound represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1,

M is a metal,

R1 to R4 are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (C _n F _{2n + 1} ; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO ₂ R, C (O) R and OR wherein R is a C 1 to C 20 alkyl group Is selected.

The present invention also provides a blue phosphorescent organic light emitting device comprising the metal complex compound of Formula 1.

According to a preferred embodiment, the blue phosphorescent organic light emitting device according to the present invention comprises: a cathode; A hole transporting layer formed on the anode; A light emitting layer formed on the hole transporting layer; An electron transport layer formed on the light emitting layer; And a cathode formed on the electron transport layer, wherein the light emitting layer comprises the metal complex compound of Formula 1.

According to the present invention, all of the ligands bound to the central atom have ligands of the same hard structure, which can not be clarified, but they are electrochemically stable and have a long life, and are also excellent in the color coordinate property as a blue phosphorescent organic light emitting device.

1 is an energy band diagram of a blue phosphorescent organic light emitting device (PhOLED) fabricated according to an embodiment of the present invention.

As mentioned above, metal complexes are useful as dopants for blue phosphorescent organic light emitting devices (PhOLEDs), and these metal complexes typically have a main ligand coordinated to the central atom (metal) Have an ancillary ligand. At this time, as described above, conventionally, attention has been focused on the main-ligand. However, the inventors of the present invention have found that when ligands having a rigid structure at the central atom are all arranged in the same manner, particularly when the specific ligand of the present invention is used, the ligand is electrochemically stable and has a long life characteristic, Thus, the present invention has been completed.

Hereinafter, the present invention will be described in detail.

The present invention provides metal complexes containing only the same ligand of a specific structure and a blue phosphorescent organic light emitting device (PhOLED) containing the same.

The metal complex according to the present invention has a specific structure represented by the following general formula (1).

[Chemical Formula 1]

In the formula 1, the central atom M is selected from iridium (Ir), platinum (Pt), osmium (Os) and ruthenium (Ru), and more preferably iridium (Ir) or platinum .

In the above formula (1), R1 to R4 may be the same or different from each other and are selected from the group consisting of hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano (CN), fluorocarbon _n F _{2n + 1;.} here, n is an integer of 1 or more), vinyl trifluoroacetate, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO ₂ R, C (O) R, and OR, and the like. Here, R is a C1 to C20 alkyl group.

In the formula 1, R 1 to R 4 are more specifically selected from H, F, C 1 to C 20 alkyl groups, fluorocarbons (C _n F _{2n + 1} ; n is an integer of 1 or more), cyano groups good. Preferably, R1 is an alkyl group of C1 ~ C20, R2 and R4 are F, R3 is preferably a CF _3. In the present invention, the alkyl group may be selected from, for example, a methyl group, an ethyl group, a propyl group, and a butyl group, but is not limited thereto. For example, the propyl group includes an n-propyl group and an iso-propyl group, and the butyl group is an n-butyl group ( n-butyl group, iso-butyl group and tertiary-butyl group.

According to the present invention, it has a phenylpyridine structure, which is a rigid ligand, and is particularly electrochemically stable, so that it has excellent long-life characteristics when applied to a blue phosphorescent organic light emitting device (PhOLED).

Preferred according to the embodiment, the metal complex compounds according to the invention, R2 and R4 are F In Formula 1, R3 is as in CF _3, to preferably represented by formula 2.

(2)

In the formula (2), R1 is a C1-C20 alkyl group. In the above formula (2), more preferably, R 1 is a methyl group (CH ₃ ). And the central atom M is preferably Ir or Pt. With such a structure, it is possible to have excellent color coordinates with CF ₃ bonded to the phenyl group of the ligand, and at the same time to have a long-life characteristic.

The metal complex according to the present invention can be produced by various synthetic methods, and the production method thereof is not limited. Exemplary synthetic methods are illustrated in the following examples.

The metal complex according to the present invention has a blue phosphorescence property and is not clear as described above, but since it has a phenyl pyridine structure having a wide energy band gap as a ligand, rigid characteristics. Accordingly, when the phosphor is used as a dopant of a blue phosphorescent organic light emitting device (PhOLED), it is electrochemically stable, thereby achieving excellent color coordinates and excellent long life characteristics.

Meanwhile, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention includes the metal complex according to the present invention. Specifically, the blue phosphorescent organic light emitting diode (PhOLED) according to the present invention has a plurality of organic thin film layers as in the conventional art, and at least one of the organic thin film layers includes the metal complex according to the present invention. More specifically, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention includes a metal complex according to the present invention as a dopant for blue phosphorescence.

According to an exemplary aspect of the present invention, a blue phosphorescent organic light emitting device (PhOLED) according to the present invention includes an anode; A light emitting layer (EML) formed on the anode; And a cathode formed on the light emitting layer (EML).

According to a preferred embodiment, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention may have a multi-layer structure including a hole transport layer (HTL) and an electron transport layer (ETL). Specifically, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention has a general multi-layer structure including an anode; A hole transport layer (HTL) formed on the anode; A light emitting layer (EML) formed on the hole transport layer (HTL); An electron transport layer (ETL) formed on the light emitting layer (EML); And a cathode formed on the electron transport layer (ETL).

At this time, the light emitting layer (EML) includes the metal complex of the present invention as described above.

Further, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention may include a hole injection layer (HIT) formed between the anode and the hole transport layer (HTL), as occasion demands; And an electron injection layer (EIL) formed between the electron transport layer (ETL) and the cathode. In addition, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention may include a substrate for supporting the layers. Each layer will be described as follows.

The substrate may have any supporting force. The substrate can be selected from, for example, a glass substrate or a polymer substrate. Further, the substrate may be selected from a polymer substrate in consideration of flexibility, and may be made of a polymer including, for example, one or more resins selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polycarbonate And a polymer substrate (film).

The anode is not limited. The anode is made of, for example, indium-tin-oxide (ITO), indium-zinc-oxide (IZO), tungsten oxide (WO), tin oxide (SnO), zinc oxide (ZnO) ; Metal nitrides such as titanium nitride; Metals such as gold, platinum, silver, copper, aluminum, nickel, cobalt, lead, molybdenum, tungsten, tantalum and niobium; An alloy of such a metal or an alloy of copper iodide; And conductive polymers such as polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, poly (3-methylthiophene), and polyphenylene sulfide; And the like. The anode may be selected from transparent electrodes selected from ITO, IZO and WO, for example.

The hole transport layer (HTL) may be formed as usual. The hole transporting layer (HTL) includes a hole transporting material, which may include, for example, N, N'-bis (naphthalen-1-yl) -N, N'- NPB) and di [4- (N, N'-ditolyl-amino) -phenyl] cyclohexane (Di- [ 4- (N, N-ditolyl-amino) -phenyl] cyclohexane; TAPC).

The light emitting layer (EML) may be a single layer or a multilayer, including a host for charge transport and a dopant for blue phosphorescence. At this time, the dopant is selected from the metal complexes of the present invention as described above. The host may use conventional ones, for example, 4,4'-bis (carbazol-9-yl) -2,2'-dimethylbiphenyl (CDBP), 4,4'-N, N Dicarbazole biphenyl (CBP), 1,3-N, N-dicarbazole benzene (mCP) and derivatives thereof. In addition, the host can be selected from the group consisting of (4,4'-bis (2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi), bis (styryl) amine (Triphenylsiloxy) aluminum (III) (SAlq), bis (2-methyl-8-quinolinolato) (para-phenolato) aluminum (III) (BAlq) (4-ethylphenyl) -1,2,4-triazole (p-EtTAZ), 3- (4-biphenyl) -4- Phenyl-4- (4-tert-butylphenyl) -1,2,4-triazole (TAZ), 2,2 ', 7,7'-tetrakis (P-TTA), 5,5-bis (dimeptylboryl) -2,2-bis (trimethylsilyl) (BMB-2T), perylene, and the like.

The electron transport layer (ETL) is not limited as long as it has an electron transporting ability, for example, an aryl-substituted oxadiazole, aryl-substituted triazole, aryl-substituted phenanthroline, benzothiazole, Azole compound, and specific examples thereof include 4-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl (BAlq), 1,3- (OXD-7), 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), and Tris (8-quinolinato) aluminum (III) (Alq3) and the like.

According to a preferred embodiment, the electron transport layer (ETL) preferably contains at least one selected from the compounds represented by the following formulas (3) and (4).

(3)

[Chemical Formula 4]

In the above formulas 3 and 4, R 'and R "are independent of each other. Specifically, R' and R" are the same or different from each other and are each selected from hydrogen (H), an aliphatic compound and an aromatic compound. More specifically, R 'and R "are a hydrogen atom, an alkyl group, a C6 to C20 aryl group, a C3 to C20 heteroaryl group, a C3 to C20 heteroaryl substituted alkyl group, Or an aryl group substituted with a C3-C20 heteroaryl group, etc. According to a preferred embodiment, the R 'and R "may be selected from an alkyl group or a phenyl group, C20, for example, a methyl group, an ethyl group, a propyl group, a butyl group and the like.

According to a preferred embodiment of the present invention, when the electron transport layer (ETL) comprises the Si-organic composite represented by the above chemical formula 3 and / or the chemical formula 4, the energy level between the light emitting layer (EML) and the electron transport layer (ETL) HOMO energy level) is not large and is useful in the present invention. Specifically, according to the present invention, the compound represented by Chemical Formula 3 and Chemical Formula 4 has a small difference in energy level from the metal complex compound of the present invention contained in the light emitting layer (EML), thereby having excellent device characteristics. More specifically, the injection of electrons from the cathode to the light emitting layer (EML) is maximized, and the movement of holes from the light emitting layer (EML) to the cathode is effectively blocked, so that the device characteristics of excellent light emitting efficiency are obtained.

In addition, the hole injection layer (HIL) and the electron injection layer (EIL) may be included as the case may be, as described above. The hole injecting layer (HIL) and the electron injecting layer (EIL) may be formed, for example, from N, N'-bis (naphthalen-1-yl) -N, N'- Phenyl) amino cyclohexane (TAPC), 4,4'-bis {N- (1-naphthyl) -N- , PEDOT / PSS, copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine (m-MTDATA), and 4,4' 2-naphthyl) -N-phenyl-amino) -triphenylamine (2-TNATA).

The negative electrode is not limited, and a conventional one can be used. The cathode can be selected, for example, from metal. The negative electrode may include one or more alloys selected from Al, Ca, Mg and Ag, for example. More specifically, for example, an alloy containing Al or Al may be coated with LiF.

In addition, the thicknesses of the respective layers constituting the blue phosphorescent organic light emitting device (PhOLED) in the present invention are not limited. In addition, the layers may be formed by a conventional method, for example, a vacuum deposition method such as sputtering according to each layer, hot air drying after coating the liquid, or high-temperature baking after coating, and the forming method is not limited Do not.

The above-described blue phosphorescent organic light emitting device (PhOLED) according to the present invention has excellent luminescence efficiency and excellent long life characteristics. Specifically, the dopant constituting the light-emitting layer (EML) includes the metal complex of the present invention as described above, and has electrophoretically stable blue phosphorescence characteristics and long lifetime characteristics and excellent color coordinates. In addition, when the compound represented by Chemical Formula 3 and / or Chemical Formula 4 is applied as the electron transport layer (ETL), the difference in energy level from the dopant (metal complex compound) of the light emitting layer (EML) .

Hereinafter, examples and comparative examples of the present invention will be exemplified. The following examples are provided to aid understanding of the present invention, and thus the technical scope of the present invention is not limited thereto.

[Synthesis Example]

The iridium (Ir) complex was prepared (synthesized) by the following synthesis procedure, and the reaction in each process was as shown in the following reaction formula 1.

(1) Synthesis of 2- (2,4-difluorophenyl) -4-methylpyridine

Phenyl beams 2,4 in a reaction vessel Nick Acid (2,4-difluorophenylboronic acid) 3g ( 19.00 mmol) and tetrakis (triphenylphosphine) palladium _{[Pd (PPh 3) 4]} 1.1g (0.95 mmol) and dissolved in THF (100 mL). Thereafter, 40 mL of a 5 wt% K ₂ CO ₃ aqueous solution was added, and the mixture was refluxed under a nitrogen atmosphere for 18 hours.

Next, after the mixture was cooled, water was added and extracted with ethyl acetate. And the organic layer was dried over magnesium sulfate (MgSO _4), and the solvent was removed under reduced pressure to obtain the crude residue. Thereafter, the crude product was purified by silica gel column chromatography to obtain 2.5 g of 2- (2,4-difluorophenyl) -4-methylpyridine in a yield of 65% 4-methylpyridine). ^{1 H NMR (300.1 MHz, CDCl} 3): d (ppm) 8.55 (d, 1H), 7.96 (m, 1H), 7.55 (s, 1H), 7.07 (d, 1H), 6.99 (t, 1H), 6.90 (t, 1 H), 2.41 (s, 3 H); ^{13 C NMR (75.4 MHz, CDCl} 3): d (ppm) 164.73, 164.57, 162.17, 162.01, 161.41, 161.25, 158.83, 158.67, 152.32, 152.29, 149.40, 147.51, 132.247, 132.19, 132.12, 132.06, 125.10, 124.99 , 123.80, 123.41, 111.91, 111.86, 111.63, 111.58, 104.59, 104.26, 104.23, 103.90, 21.15; HRMS (FAB) calcd. for [M + H] < ⁺ > 205.0703, Found: 205.0712; Anal. Calcd for C ₁₂ H ₉ F ₂ N: C, 70.24; H, 4.42; F, 18.52; N, 6.83. Found: C, 70.26; H, 4.40; N, 6.87.

(2) Synthesis of 2- (2,4-difluoro-3-iodophenyl) -4-methylpyridine

2 g (9.75 mmol) of 2- (2,4-difluorophenyl) -4-methylpyridine obtained in the above step (5) was added to a Schröst flask and dissolved in 40 mL of THF. Then, 9.19 ml (23 mmol) of a 2.0 M solution of lithium diisopropyl amide dissolved in a mixed solvent of heptane / tetrahydrofuran / ethylbenzene was added under cooling and temperature conditions of -78 ° C Was added dropwise and stirred for 1 hour. Then 5.58 g (22 mmol) of iodine dissolved in 32 mL of tetrahydrofuran (THF) was added and the mixture was stirred at -78 [deg.] C for 3 hours and warmed to room temperature.

Next, 300 mL of water was added to the mixture, and the resulting solution was extracted twice (100 mL x 2) using diethyl ether. The ether solution was then washed with 100 mL of water, 100 mL of saturated sodium thiosulfate (Na ₂ S ₂ O ₃ ) aqueous solution and 100 mL of saturated sodium chloride (NaCl) solution, then dried with sodium sulfate, The liquid was evaporated in vacuo. The residue was purified by silica gel column chromatography using a mixed solvent of ethyl acetate: hexane = 1: 6 to obtain 2.1 g of beige powder 2- (2,4-difluoro- 2- (2,4-difluoro-3-iodophenyl) -4-methylpyridine. ^{1 H NMR (300.1 MHz, CDCl} 3): d (ppm) 8.56 (d, 1H), 7.95 (m, 1H), 7.56 (s, 1H), 7.10 (d, 1H), 7.01 (t, 1H), 2.42 (s, 3 H); ^{13 C NMR (75.4 MHz, CDCl} 3): d (ppm) 164.42, 164.36, 161.46, 161.38, 161.06, 158.07, 151.80, 149.77, 149.66, 149.46, 147.78, 132.31, 125.36, 125.24, 125.15, 124.46, 123.92, 123.78 , 123.57, 123.16, 112.35, 111.69, 111.23, 21.38; HRMS (FAB) calcd. for [M + H] < ⁺ > 330.9669, Found: 330.9672; Anal. Calcd for C ₁₂ H ₈ F ₂ IN: C, 43.53; H, 2.44; F, 11.48; I, 38.33; N, 4.23. Found: C, 43.50; H, 2.47; N, 4.22.

(3) Synthesis of 2- (2,4-difluoro-3- (trifluoromethyl) phenyl) -4-methylpyridine

A mixture of 1.73 g (9.1 mmol) of copper (I) iodide and 0.53 g (9.1 mmol) of anhydrous potassium fluoride was prepared and the color of the mixture turned yellow Was heated with a heat gun under reduced pressure while shaking slightly. After 2.0 g (6.04 mmol) of 2- (2,4-difluoro-3-iodophenyl) -4-methylpyridine obtained in the above step (6) was added, the reaction vessel was evacuated with argon, N-methylpyrrolidinone and (trifluoromethyl) trimethylsilane were added to the mixture.

Next, the above mixture was strongly stirred at room temperature for 24 hours, then put into 66 mL of 28 wt% aqueous ammonia solution and extracted with dichloromethane. The organic layer was washed with water and brine, dried over sodium sulfate, and the filtrate was evaporated in vacuo. The residue was purified by silica gel column chromatography using a mixed solvent of ethyl acetate: hexane = 1: 6 to obtain 0.5 g of white powder of 2- (2,4-difluoro- 2- (2,4-difluoro-3- (trifluoromethyl) phenyl) -4-methylpyridine was obtained. ^{1 H NMR (300.1 MHz, CDCl} 3): d (ppm) 8.56 (d, 1H), 8.15 (m, 1H), 7.57 (s, 1H), 7.13-7.08 (m, 2H), 2.42 (s, 3H ); ^{13 C NMR (75.4 MHz, CDCl} 3): d (ppm) 161.63, 159,38, 158.16, 155.95, 151,10, 149.91, 149.53, 148.07, 135.64, 125.60, 125.49, 125.30, 124.39, 123.99, 123.69, 120.07 , 113.45, 113.09, 112.74, 21.34; HRMS (FAB) calcd. for [M + H] < ⁺ > 273.0577, Found: 273.0580; Anal. _{calcd for C 13 H 8 F 5} N: C, 57.15; H, 2.95; F, 34.77; N, 5.13. Found: C, 57.13; H, 2.97; N, 5.14.

(4) Synthesis of iridium (trivalent) -chlorodiglyceride (Ir (III) - m -chloro-bridged Dimer Complexes)

The reaction vessel was charged with 0.11 g (0.36 mmol) of iridium (trivalent) chloride trihydrate and 2 g of (2- (2,4-difluoro-3- (2-ethoxyethanol / H ₂ O) was added to a total of 8 mL (6 mL / 2 mL) at a ratio of 3: 1, Of a solvent. Thereafter, the mixture was refluxed at 120 DEG C for 18 hours under a nitrogen atmosphere. After cooling to room temperature, the mixture was evaporated in vacuo and water was added to the residue.

Next, the mixture was extracted with dichloromethane. The organic layer was washed with water and brine, dried over sodium sulfate, and the filtrate was evaporated in vacuo to yield 0.22 g of Ir (III) -m- chloro-bridged Dimer Complexes were obtained. ^{1 H NMR (300.1 MHz, CDCl} 3): d (ppm) 8.89 (d, 1H), 8.21 (s, 1H), 6.71 (d, 1H), 8.89 (d, 1H), 5.40 (d, 1H) 2.73 (s, 3 H); ¹³ C NMR (75.4 MHz, CDCl ₃ ): d (ppm) 163.61, 160.45, 158.63, 155.10, 152.52, 150.51, 150.36, 129.08, 124.37, 120.24, 120.22, 114.33, 114.06, 21.90, 21.23; HRMS (FAB) calcd. for [M + H] < ⁺ > 1544.0630, Found: 1544.0637; Anal. calcd for C ₅₂ H ₂₈ Cl ₂ F ₂₀ IrN ₄ : C, 40.45; H, 1.83; Cl, 4.59; F, 24.61; Ir, 24.90; N, 3.63. Found: C, 40.47; H, 1.82; N, 3.65.

[Example 1]

<Synthesis of metal (Ir) complex of the present invention>

An iridium (trivalent) complex was synthesized by reacting the compound obtained through the above Synthesis Examples (3) and (4) as follows.

To the reaction vessel were added 0.13 g (0.08 mmol) of the iridium (tri) -chloro-dimer obtained in the above (4) and 2- (2,4-difluoro- (Trifluoromethyl) phenyl) -4-methylpyridine (0.12 g, 0.42 mmol) and 0.01 g (0.04 mmol) of silver trifluoromethanesulfonate (CF ₃ SO ₃ Ag). And heated at 180 DEG C or higher for 12 hours.

Next, after cooling to room temperature, the mixture was extracted with dichloromethane, the organic layer was dried with magnesium sulfate, and the filtrate was evaporated in vacuo. The residue was purified by silica gel column chromatography to finally obtain 0.01 g of a yellow powdered iridium (III) complex (15% yield).

The final product (5) (Ir complex compound) according to the present invention thus synthesized had the structure shown in the following Reaction Scheme 1, which was confirmed by ¹ H-NMR analysis. ¹ H NMR (300.1 MHz, CDCl ₃ ): d (ppm) 8.19 (s, IH), 7.28 (d, IH), 6.87 (d, IH), 6.33 (d, IH), 2.48 (s, 3H); ^{13 C NMR (75.4 MHz, CDCl} 3): d (ppm) 168.88, 168.78, 161.61, 161.46, 161,37, 159.97, 158.13, 156.41, 149.67, 146.68, 146.31, 128.63, 128.32, 125.34, 125.01, 124.79, 124.69 , 124.09, 121.10, 21.96, 21.73, 20.93; HRMS (FAB) calcd. for [M + H] &lt; ⁺ &gt; 1009.1125, Found: 1009.1130; Anal. calcd for C ₃₉ H ₂₁ F ₁₅ IrN ₃ : C, 46.43; H, 2.10; F, 28.25; Ir, 19.05; N, 4.17. Found: C, 46.40; H, 2.11; N, 4.15. In the following Reaction Scheme 1, Me is a methyl group (CH ₃ ).

[Reaction Scheme 1]

<Device Manufacturing>

A hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer (EML), and an electron transport layer (ITO) were formed on the ITO film by a conventional deposition method. ETL) and a cathode were formed.

At this time, the hole injection layer (HIL) was formed to a thickness of 500 ANGSTROM using NPB (N, N'-bis (naphthalen-1-yl) -N, N'-bis HTL) was formed with a thickness of 350 A using TAPC (di- [4- (N, N'-ditolyl-amino) -phenyl] cyclohexane).

The light emitting layer (EML) is formed by first depositing CDBP (4,4'-bis (carbazol-9-yl) -2,2'-dimethylbiphenyl) on the hole transport layer , And a mixture of host (CDBP) and a dopant (host: dopant = 90: 10 molar ratio) was formed thereon to a thickness of 500 Å. At this time, the dopant used was the final product (Re complex) of Scheme 1 obtained in the above synthesis.

Further, the electron transport layer (ETL) is a Si- organic compounds represented by the above formula (3), in the formula (3) R 'and R "would be the all _{-CH 3 [Me 2 Si (TAZ} ) 2] using a 600Å thick The cathode was formed by using LiF / Al, a glass substrate // anode [ITO] // hole injecting layer [NPB] // hole transporting layer [TAPC] // light emitting layer [CDBP / CDBP + Ir dopant (10 mol%)] // electron transport layer [Me ₂ Si (TAZ) ₂ ] // cathode [LiF / Al].

FIG. 1 shows an energy band diagram of a blue phosphorescent organic light emitting device (PhOLED) manufactured according to the present invention. 1, the values 2.4, 2.0, 2.5 and 2.52 shown above are the LUMO energy levels (eV) of each layer and the values 5.4, 5.5, 6.1 and 6.45 indicated below are the HOMO energy levels (eV) to be.

[Comparative Example 1]

The Ir dopant of the light emitting layer (EML) was prepared by the same method as that of the above example, except that FIr6, which is conventionally used, was used. Specifically, glass substrate // anode [ITO] // hole injection layer [NPB] // hole transport layer [TAPC] // light emitting layer [CDBP / CDBP + FIr6 (10 mol%)] // electron transport layer [Me ₂ Si TAZ) ₂ ] // PhOLED having the lamination structure of the cathode [LiF / Al] was used as the test piece of this Comparative Example 1. [ The following formula shows the structure of FIr6 used as a dopant of this Comparative Example 2. [

&Lt; Evaluation of optical properties and element characteristics of Ir complex &

The photophysical properties (PL spectrum) of the above Examples and Comparative Examples were evaluated, and the results are shown in Table 1 attached hereto.

As a result, as shown in Table 1, it was confirmed that the reaction was carried out with a ligand of 2- (2,4-difluoro-3- (trifluoromethyl) phenyl) -4-methylpyridine synthesized according to an embodiment of the present invention Ir complexes exhibited excellent characteristics at a current density [mA / cm 2] at 12 V and a y-axis of 0.20 which is superior to the comparative example of 0.23 in the color coordinate system. Particularly, in the half-life of 50% , Respectively.

[Table 1] Evaluation results of device characteristics

As can be seen from the above examples, the metal compound according to the present invention contains only a ligand having a rigid structure and is electrochemically stable. PhOLED including the metal compound has excellent color coordinate device characteristics, It can be seen that it has very good long life characteristics in time.

Claims (7)

A blue phosphorescent light emitting device comprising a metal complex represented by the following formula (1) comprises a cathode, a hole transport layer formed on the anode, a light emitting layer formed on the hole transport layer, an electron transport layer formed on the light emitting layer, and a cathode formed on the electron transport layer And at least one selected from compounds represented by the following general formulas (3) and (4) is contained in the electron transport layer.
[Chemical Formula 1]

In Formula 1,
M is a metal,
R1 to R4 are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (C _n F _{2n + 1} ; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO ₂ R, C (O) R and OR wherein R is a C 1 to C 20 alkyl group Selected,
(3)

[Chemical Formula 4]

In the above formulas (3) and (4)
R 'and R "are selected from hydrogen, an aliphatic compound and an aromatic compound.
The method according to claim 1,
Wherein the R1 is a methyl group (CH3), R2 and R4 are F, and R3 is CF3 or CN.
3. The method according to claim 1 or 2,
The blue phosphorescent organic light emitting device includes a cathode, a light emitting layer formed on the anode, and a cathode formed on the light emitting layer.
delete delete The method according to claim 1,
Wherein R 'and R "in the general formulas (3) and (4) are C1-C20 alkyl groups or phenyl groups.
A metal complex represented by the following formula (1)
[Chemical Formula 1]

In Formula 1,
M is a metal,
R1, R2 and R4 are each independently selected from fluorine (F), C1-C20 alkyl group, fluorocarbon (CnF2n + 1 wherein n is an integer of 1 or more) and cyano group (CN);
R3 is selected from hydrogen (H), fluorine (F), fluorocarbon (CnF2n + 1 where n is an integer of 1 or more) and cyano group (CN).

Images