KR20170103731A - Metal complex for dopant of a light emitting layer and blue phosphorescent organic light emitting device comprising the same - Google Patents

Abstract

An objective of the present invention is to provide a metal complex compound for a dopant of a light emitting layer, which may have improved color coordinates, increased efficiency and improved stability. The metal complex compound for the dopant of the light emitting layer of the present invention comprises a metal complex compound represented by chemical formula 1. Further, a blue phosphorescent organic light emitting device of the present invention comprises: a pair of first and second electrodes; and a light emitting layer which is interposed between the first and second electrodes and generates excitons to extract a light, wherein the light emitting layer includes a metal complex compound represented by chemical formula 1.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal complex for a dopant of a light emitting layer and a blue phosphorescent organic light emitting device including the same.

The present invention relates to a metal complex for a dopant of a light emitting layer and a blue phosphorescent organic light emitting device containing the same. More particularly, the present invention relates to a blue phosphorescent organic electroluminescent device including a metal complex compound contained as a dopant in a light emitting layer included in an organic light emitting device, and a light emitting layer doped with the metal complex.

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) And is being applied to mobile displays.

In addition, it has been known that not only fluorescent materials but also phosphorescent materials can be used as organic light emitting devices (OLEDs). Photoluminescence phosphorescence is a phenomenon in which electrons are transferred from ground states to excited states and then singlet excitons are emitted as non-luminescent transitions to triplet excitons through intersystem crossing Next, a triplet exciton is caused to emit light while transitioning to a bottom state. 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 the case of electroluminescence, single-exciton and triplet exciton are formed in a one-to-three ratio. Generally, a fluorescent material has an internal quantum efficiency of up to 25%, while a phosphorescent material has an internal quantum efficiency of up to 100% And research and development of a phosphorescent material is being actively carried out.

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 internal quantum 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, improvement of the layer structure of the device and research on new materials of the host and the dopant are proceeding.

In recent years, research is being conducted on such dopants. For example, Korean Patent Publication No. 10-2010-0061831 discloses a technique for a metal complex as a dopant.

However, when a conventional metal complex used as a dopant, that is, a blue phosphorescent material according to the related art, is applied to a light emitting layer as a dopant, it is required to improve the color coordinate, deterioration of efficiency of the dopant and non- There is a problem that the stability is deteriorated.

Accordingly, it is an object of the present invention to provide a metal complex for a dopant of a light emitting layer which can have improved color coordinates and increased efficiency and improved stability.

It is another object of the present invention to provide a blue phosphorescent organic light emitting device which can have improved color coordinates and increased efficiency and improved stability.

In order to accomplish the object of the present invention, the metal complex compound for the dopant of the light emitting layer is represented by the following chemical formula 1.

[Chemical Formula 1]

In Formula 1, M is a metal,

R1 to R4 of the main ligand are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (CnF2n + 1; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO2R, C (O) R and OR wherein R is a C1 to C20 alkyl group ,

An ancillary ligand is selected by using one of the following formula (2). Where n is 1 or 2 and m is 0 to 3, and when n is 1, m is 1 to 3. When n is 2, m is 1. X and Y respectively denote aryl or acen compounds of heterocyclic auxiliary ligands containing C or N, O, P, and B elements, respectively.

(2)

In order to accomplish the object of the present invention, a blue phosphorescent organic light emitting diode includes a pair of first and second electrodes, a light emitting layer interposed between the first and second electrodes, And the light emitting layer includes a metal complex represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, M is a metal,

R1 to R4 of the main ligand are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (CnF2n + 1; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO2R, C (O) R and OR wherein R is a C1 to C20 alkyl group ,

An ancillary ligand is selected by using one of the following formula (2). Where n is 1 or 2 and m is 0 to 3, and when n is 1, m is 1 to 3. When n is 2, m is 1. X and Y respectively denote aryl or acen compounds of heterocyclic auxiliary ligands containing C or N, O, P, and B elements, respectively.

(2)

The blue phosphorescent organic light emitting device according to an embodiment of the present invention may further include a hole injection layer and a hole transport layer disposed between the first electrode and the light emitting layer, and an electron transport layer disposed between the second electrode and the light emitting layer .

The metal complex compound for the dopant of the light emitting layer according to embodiments of the present invention includes a main ligand of phenylpyridine series coordinated to a central metal atom and an ancillary ligand having a relatively large size and hardness And has a heteroleptic structure. Therefore, the blue phosphorescent organic light emitting device including the light emitting layer in which the metal complex compound is applied as a dopant has an improved color coordinate, durability against non-emission cleavage by the exciton and prevention of degradation of the dopant.

Accordingly, the metal complex can have improved stability and efficiency as a dopant, and further, can realize a blue phosphorescent organic light emitting device having improved color coordinate characteristics.

1 is a cross-sectional view illustrating a blue phosphorescent organic light emitting device (PhOLED) manufactured according to an embodiment of the present invention.

Hereinafter, a metal complex for a dopant of a light emitting layer and a blue phosphorescent organic light emitting device including the same according to an embodiment of the present invention will be described in detail. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

For dopant  Metal complex

The metal complex compound for a dopant of the light emitting layer according to embodiments of the present invention includes a metal complex represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, M is a metal,

R1 to R4 of the main ligand are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (CnF2n + 1; ), Trifluoropropyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO2R, C (O) R and OR wherein R is a C1 to C20 alkyl group .

An ancillary ligand is selected by using one of the following formula (2).

Where n is 1 or 2 and m is 0 to 3, and when n is 1, m is 1 to 3. When n is 2, m is 1. X and Y respectively denote aryl or acen compounds of heterocyclic auxiliary ligands containing C or N, O, P, and B elements, respectively.

(2)

Metal complexes according to embodiments of the present invention include primary and secondary ligands of the phenyl pyridine series. Thus, the metal complex containing the main ligand containing the phenylpyridine series can have improved electrochemical stability and lifetime characteristics, as well as having an auxiliary ligand having a relatively large and rigid property, the energy of the main ligand It is possible to have an improved color coordinate characteristic by moving the level.

The blue phosphorescent organic light emitting element

A blue phosphorescent organic light emitting device (PhOLED) according to the present invention includes a first electrode functioning as an anode; A light emitting layer (EML) formed on the anode; And a second electrode functioning as a cathode formed on the light emitting layer (EML). Therefore, the blue phosphorescent organic light emitting diode may have a multi-layer structure.

The blue phosphorescent organic light emitting device (PhOLED) according to an exemplary embodiment of the present invention may further include a hole injection layer (HIL), a hole transport layer (HTL), and a buffer layer (BL). Specifically, a blue phosphorescent organic light emitting device (PhOLED) according to the present invention includes a first electrode functioning as an anode, a hole injection layer (HIL) formed on the anode, a hole transport layer (HTL) formed on the hole injection layer ), A buffer layer (BL) formed on the hole transport layer (HTL), an emission layer (EML) formed on the buffer layer, an electron transport layer (ETL) formed on the emission layer (EML) and a second electrode functioning as a cathode.

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

In addition, the blue phosphorescent organic light emitting device (PhOLED) according to the present invention may include a substrate for supporting the layers.

The substrate may be provided to support the first electrode. The substrate may include, for example, a glass substrate or a flexible substrate made of a polymer material. Examples of the polymer material included in the flexible substrate may include at least one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC).

The first electrode may be formed of a material selected from the group consisting of indium-tin-oxide (ITO), indium-zinc-oxide (IZO), tungsten oxide (WO), tin oxide (SnO), zinc oxide (ZAO); 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 a conductive polymer such as polyaniline, polythiophene, polypyrrole, polyphenylene vinylene, poly (3-methylthiophene), and polyphenylene sulfide. The first electrode may be made of a material having optically transparent characteristics such as ITO, IZO and WO.

The hole injection layer (HIL) is disposed between the first electrode and the hole transport layer.

The HIL may be, for example, HAT-CN (1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile), N, N'-bis (naphthalen- Bis (phenyl) -benzidine (NPB) and di- [4- (N, N'-ditolyl-amino) -phenyl] cyclohexane (TAPC), 4,4'- NPD), PEDOT / PSS, copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine (m-MTDATA ), And 4,4 ', 4 "-tris (N- (2-naphthyl) -N-phenyl-amino) -triphenylamine (2-TNATA).

The hole transport layer (HTL) is disposed on the first electrode. The HTL may be a hole transport material such as N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) N, N'-ditolyl-amino) -phenyl] cyclohexane (TAPC).

The buffer layer (BL) is disposed on the hole transport layer (HTL). A ((methylsilanetriyl) tris (benzene- 4,1-diyl)) tris (9 H -carbazole) 9,9 ', 9''- - (4,4', 4 '') the buffer layer (BL) is MCBP Lt; / RTI >

The light emitting layer (EML) is disposed on the hole transport layer. The light emitting layer (EML) may be a host for charge transport and a dopant material for blue phosphorescence. At this time, the dopant may include at least one of the metal complexes of the present invention as described above.

On the other hand, the host can be, for example, 4,4'-bis (carbazol-9-yl) -2,2'-dimethylbiphenyl (CDBP), 4,4'- (CBP), 1,3-N, N-dicarbazole benzene (mCP), MCBP (9,9 ', 9''-(4,4' 1-diyl)) tris (9 H -carbazole)) 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), and perylene.

The electron transport layer (ETL) is disposed on the light emitting layer. The electron transport layer (ETL) may be selected from, for example, aryl-substituted oxadiazoles, aryl-substituted triazoles, aryl-substituted phenanthrolines, benzothiazole and benzothiazole compounds, (N, N-butyl-phenyl) -1,3,4-tetrahydro-naphthalen-1-yl] (OXD-7), 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ), and tris (8- quinolinato) aluminum III) (Alq3).

And the second electrode is disposed on the electron transporting layer. The second electrode may be selected, for example, from a metal. The second electrode may include one or more alloys selected from, for example, Al, Ca, Mg and Ag. More specifically, for example, the second electrode may be made of an alloy containing Al or Al 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. The respective layers may be formed by a conventional method such as a vacuum evaporation method such as thermal evaporation according to each layer, hot air drying after liquid coating, or high temperature baking after coating, The formation method thereof is not limited.

[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) 2- (2,4- Difluorophenyl )-4- Methylpyridine  synthesis

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) 2- (2,4- Difluoro -3- Iodophenyl )-4- Methylpyridine  synthesis

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 lithium diisopropyl amide (LDA) solution, which was dissolved in a mixed solvent of heptane / tetrahydrofuran / ethylbenzene, at a cold temperature 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) 2- (2,4- Difluoro -3- ( Trifluoromethyl ) Phenyl) -4- Methylpyridine  synthesis

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) iridium (3) -chloro-bridged dimer (Ir (III) - m-chloro -bridged Dimer Synthesis of 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.

≪ Synthesis of metal (Ir) complexes according to embodiments of the present invention >

[Example 1]

An iridium (trivalent) complex was synthesized by reacting the compound obtained in Synthesis Example (4) as follows.

0.31 g (0.49 mmol) of silver trifluoromethanesulfonate (CF ₃ SO ₃ Ag), 0.4 g (0.15 mmol) of iridium (trivalent) -chlorodiglyceride obtained in the process (4) ) Was dissolved in 20 ml of dichloromethane (MeOH) solution. The reaction mixture was stirred at room temperature for 2 hours. The reaction mixture is filtered using a cannula to remove salts. The residue is dissociated in 20 ml of acetonitrile (ACN) and 0.25 g (0.75 mmol) of potassium tetrakis (1-pyrazolyl) borate salt is added to the reaction mixture. Heat was applied to the reaction mixture and refluxed in a nitrogen atmosphere at a temperature of 150 캜 for 12 hours. Thereafter, the reaction mixture solution was extracted with dichloromethane, the organic layer was dried with magnesium sulfate, and the filtered liquid was evaporated in vacuo. The residue obtained was purified by silica gel column chromatography to give 0.07g Finally, metal (Ir) complex _{(Ir (dfCF 3) 2 (} bor)) of 0.065 mmol in a yield of 25%.

(D, J = 2.4 Hz, 2H), 7.08 (d, J = 5.7 Hz, 2H), 6.88 (s, 2H) , 2H), 6.65 (d, J = 5.1 Hz, 2H), 6.27 (s, 2H), 6.18 (s, 2H), 6.05 (s, 2H), 5.72 (d, J = 10.8 Hz, 2H), 2.50 (s, 6 H); 13 C NMR (75.4 MHz, CDCl 3), 161.2, 159.5, 159.2, 157.6, 155.6, 150.0, 149.2, 144.06, 142.4, 139.2, 133.7, 129.8, 124.6, 115.5, 115.3, 107.6, 105.9, 21.6; HRMS (FAB) calcd. for [M + H] + 1017.1905, found: 1017.1920; Anal. Calcd for C38H26BF10IrN10: C, 44.94; H, 2.58; N, 13.79. Found: C, 44.97; H, 2.56; N, 13.74.

[Example 2]

0.31 g (0.49 mmol) of silver trifluoromethanesulfonate (CF ₃ SO ₃ Ag), 0.4 g (0.15 mmol) of iridium (trivalent) -chlorodiglyceride obtained in the process (4) ) Was dissolved in 20 ml of dichloromethane (MeOH) solution. The reaction mixture was stirred at room temperature for 2 hours. The mixture is filtered using a canula to remove salts. 2- (naphthalen-2-yl) pyridine is added to the reaction mixture. Heat was applied to the reaction mixture and refluxed in a nitrogen atmosphere at a temperature of 150 캜 for 12 hours. Thereafter, the reaction mixture solution was extracted with dichloromethane, the organic layer was dried with magnesium sulfate, and the filtered liquid was evaporated in vacuo. The residue was obtained metal (Ir) complex _{(Ir (dfCF 3) 2 (} nathpy)) was purified by silica gel column chromatography.

[Example 3]

0.4 g (0.15 mmol) of the iridium (tri) -chlorodiglyme and 0.31 g (0.49 mmol) of ammonium hexafluorophosphate (NH ₄ PF ₆ ) obtained in the process (4) were added to the reaction vessel. MeOH). The reaction mixture was stirred at room temperature for 2 hours. The mixture is filtered using a canula to remove salts. (2-methyl-1H-benzo [d] imidazol-2-yl) quinoline) is added to the reaction mixture. The reaction mixture was heated and refluxed in a nitrogen atmosphere at a temperature of 150 ° C for 12 hours. Thereafter, the reaction mixture solution was extracted with dichloromethane, the organic layer was dried with magnesium sulfate, and the filtered liquid was evaporated in vacuo. The residue was obtained metal (Ir) complex _{(Ir (dfCF 3) 2 (} biq)) was purified by silica gel column chromatography.

[Comparative Example 1]

An iridium (trivalent) complex was synthesized (Ir (dfCF ₃ ) ₂ (acac)) by reacting the compound obtained in the above Synthesis Example (4) as follows.

0.3 g of Ir (III) -m -chloro-bridged dimer complexes (0.1 g, 0.19 mmol) obtained in the above Synthesis Example (4) was added to acetylacetone, 0.04 mL, 0.37 mmol, and sodium carbonate (Na ₂ CO ₃ ) (0.21 g, 1.94 mmol) were mixed in a solvent of 25 mL of 2-ethoxyethanol / H ₂ O and refluxed for 12 hours To form a mixture. After the reaction mixture was cooled at room temperature, the reaction mixture was precipitated in water, and the precipitate was collected by filtration and washing to a yellow powder. The yellow powder was purified by flash column chromatography to finally obtain 0.1 g and 0.123 mmol of the metal (Ir) complex (Ir (dfCF ₃ ) ₂ (aca)) in a yield of 65%. ≪ 1 > H NMR (300.1 MHz, CDCl3): 8.24 (d, J = 5.4 Hz , 2H), 8.13 (s, 2H), 7.11 (d, J = 5.1 Hz, 2H), 5.77 (d, J = 11.1 Hz, 2H), 5.26 (s, 1H), 2.64 (s, 6 H), 1.81 (s, 6 H); ≪ 13 > C NMR (75.4 MHz, CDCl3): , 160.2, 158.2, 157.0, 156.3, 150.6, 147.5, 128.4, 125.1, 124.8, 124.5, 120.9, 119.7, 31.2, 28.8, 21.9; HRMS (FAB) calcd. for [M + H] < + > 837.1073, Found: 837.1065; Anal. calcd for C31H21F10IrN2O2: C, 44.55; H, 2.53; N, 3.35. Found: C, 44.50; H, 2.48;

[Comparative Example 2]

Comparative Example 1 was repeated except that 0.045 g, 0.37 mmol of picolinic acid was used instead of acetylacetone and 0.06 g of sodium carbonate (Na ₂ CO ₃ ) and 0.65 mmol were used. and obtain an 60% yield of a metal (Ir) complex _{(Ir (dfCF 3) 2 (} pic)) through the same process. 1H NMR (300.1 MHz, CDCl3) : 8.56 (d, J = 6.3Hz, 1H), 8.34 (d, J = 7.8 Hz, 1H), 8.17 (s, 1H), 8.12 (s, 1H), 7.99 (t , J = 7.8 Hz, 1H) , 7.75 (d, J = 4.5 Hz, 1H), 7.48 (t, J = 6.5 Hz, 1H), 7.25 (s, 1H), 7.10 (d, J = 6.0 Hz, 1H ), 6.89 (d, J = 6.3 Hz, 1H), 5.96 (d, J = 10.8 Hz, 1H), 5.69 (d, J = 10.5 Hz, 1H), 2.58 (s, 6H); 13 C NMR (75.4 MHz, CDCl 3): 164.1, 162.6, 161.4, 161.0, 159.4, 157.7, 156.9, 155.8, 151.3, 148.1, 147.5, 138.9, 129.4, 128.8, 124.7, 120.8, 115.9, 21.7; HRMS (FAB) calcd. for [M] + 859.0869, Found: 859.0873; Anal. Calcd for C32H18F10IrN3O2: C, 44.76; H, 2.11; F, 22.12; Ir, 22.38; N, 4.89; O, 3.73. Found: C, 44.73; H, 2.14; N, 4.85.

[Comparative Example 3]

The above Synthesis Example (3) and (4) reacting the resultant compound as shown below in a process iridium (3) complex (Ir (dfCF _{3) 3)} was synthesized.

(0.3 g, 0.19 mmol) obtained in the above (4), 2- (2,4-difluoro-3- (trifluoromethyl) (Trifluoromethyl) phenyl) -4-methylpyridine (0.025 g, 0.1 mmol) and silver trifluoromethanesulfonate (CF ₃ SO ₃ Ag) (0.025 g, 0.1 mmol) To form a reaction mixture.

Next, after the reaction mixture was cooled to room temperature, the reaction mixture was extracted with dichloromethane, the organic layer was dried with magnesium sulfate, and the filtered liquid was evaporated in vacuo. Residues in final yield of 15% was purified by silica gel column chromatography to obtain an iridium (3) complex (Iridium (III) complex, Ir (dfCF _{3) 3).} This 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] < ⁺ > 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 ).

* <Evaluation of Photoluminescence Characteristics of Iridium Complexes and Calculation of Activation Energy for Non-Emission Transition>

The photoluminescence properties of the iridium complexes according to Comparative Examples 1 to 3 and Example 1 were measured, and the activation energies for non-luminescent transitions were calculated. In the case of the iridium complex according to Example 1, the activation energies for the non-luminescent transitions were significantly higher than those of the Comparative Examples 1 to 3, so that attenuation at room temperature (298K) due to non-luminescent transition versus decay lifetime at a temperature of 77K There is almost no reduction in life span and the longest damping life of 4.6 μsec. Therefore, it can be seen that the iridium complex according to Example 1 is excellent in durability against non-emission cleavage. Also, the emission peak wavelength at 450 nm is the shortest at room temperature. Therefore, this is described in detail with reference to Table 1 below.

Iridium complex Activation energy for non-luminescent transition
(kcal / mol) Room temperature luminescence characteristics Low temperature (77 K) luminescence characteristics Remarks l max (nm) t ( m s) l max (nm) t ( m s) Ir (dfCF ₃ ) ₂ (acac) 467 0.9 457 2.5 Comparative Example 1 Ir (dfCF ₃ ) ₂ (pic) 1.8 462 1.8 442 2.6 Comparative Example 2 Ir (dfCF ₃ ) ₃ 6.3 452 1.9 441 2.8 Comparative Example 3 Ir (dfCF ₃ ) ₂ (boron) 10.1 450 4.6 444 4.9 Example 1

&Lt; Production of organic light emitting device >

1 is a cross-sectional view illustrating a blue phosphorescent organic light emitting diode (PhOLED) according to an embodiment of the present invention.

1, an ITO thin film is deposited as a cathode 110 on a glass substrate, and then a hole injection layer 120 and a hole transport layer 130 are formed on the anode 110 by a conventional deposition method. The light emitting layer 140, the electron transport layer 150, and the cathode 160 were formed. A buffer layer is additionally formed between the hole transport layer 130 and the light emitting layer 140.

At this time, the hole injection layer (HIL) was formed to a thickness of 100 by using HAT-CN (1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile).

The hole transport layer (HTL) was formed to a thickness of 400 using TAPC (di- [4- (N, N'-ditolyl-amino) -phenyl] cyclohexane).

The buffer layer (BL) is MCBP (9,9 ', 9'' - (4,4', 4 '' - (methylsilanetriyl) tris (benzene-4,1-diyl)) tris (9 H -carbazole)) for To a thickness of 50 mm.

On the other hand, in the light emitting layer (EML), a mixture (host: dopant = 82: 18 mass ratio) of a host (MCBP) and a dopant as a host was formed to a thickness of 300 on the buffer layer (BL). At this time, Ir (dfCF3) 2 (bor) was used as a dopant.

Further, the electron transport layer (ETL) is 3PBI - using (3,5- bis [4- (4,5- diphenyl-1 H imidazol-2-yl) -phenyl] -pyridine) was formed to a thickness of 400.

In addition, the cathode was formed by using LiF / Al and a glass substrate / anode [ITO] / hole injection layer [HAT-CN] / hole transport layer [TAPC] / buffer layer [MCBP] / light emitting layer [MCBP + Ir dopant %)] / Electron transporting layer [3PBI] / cathode [LiF / Al].

On the other hand, the metal complexes formed by Example 1 and Comparative Example 3 were respectively applied as dopants of the light emitting layer to produce an organic light emitting device.

&Lt; Characteristic Evaluation of Organic Light Emitting Device Including a Light-Emitting Layer Doped with Iridium Complex &

The device characteristics for the organic light emitting device including the light emitting layer doped with the iridium complex according to Example 1 and Comparative Example 3 described above were measured.

The organic light emitting device including the light emitting layer formed using the iridium complex according to Example 1 as a dopant had a maximum power efficiency of 21.5 lm / W, a low turn-on voltage (3.5 V), a high current Efficiency (23.7 cd / A) and excellent external quantum efficiency (14.9%), which are described in Table 2 below.

Iridium complex  Current efficiency (cd / A) Maximum power efficiency (lm / W) Turn-on Voltage
(V) Color coordinates
CIE ( x , y ) Maximum external quantum efficiency (%) Ir (dfCF ₃ ) ₃ 15.6 9.5 4.5 (0.15, 0.17) 11.5 Ir (dfCF ₃ ) ₂ (boron) 23.7 21.5 3.5 (0.16, 0.20) 14.9

The metal complex compound for the dopant of the light emitting layer according to embodiments of the present invention includes a main ligand of phenylpyridine series coordinated to a central metal atom and an ancillary ligand having a relatively large size and hardness And has a heteroleptic structure. Therefore, the blue phosphorescent organic light emitting device including the light emitting layer in which the metal complex compound is applied as a dopant has an improved color coordinate, durability against non-emission cleavage by the exciton and prevention of degradation of the dopant.

Accordingly, the metal complex can have improved stability and efficiency as a dopant, and further, can realize a blue phosphorescent organic light emitting device having improved color coordinate characteristics.

The metal complex compound for the dopant of the light emitting layer according to embodiments of the present invention includes a main ligand of phenylpyridine series coordinated to a central metal atom and an ancillary ligand having a relatively large size and hardness And has a heteroleptic structure. Therefore, the blue phosphorescent organic light emitting device including the light emitting layer in which the metal complex compound is applied as a dopant has an improved color coordinate, durability against non-emission cleavage by the exciton and prevention of degradation of the dopant.

Accordingly, the metal complex can have improved stability and efficiency as a dopant, and further, can realize a blue phosphorescent organic light emitting device having improved color coordinate characteristics.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (3)

A metal complex for a dopant of a light emitting layer comprising a metal complex represented by the following formula (1).
[Chemical Formula 1]

In Formula 1, M is a metal,
R1 to R4 of the main ligand are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (CnF2n + 1; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO2R, C (O) R and OR wherein R is a C1 to C20 alkyl group ,
An ancillary ligand is selected by using one of the following formula (2). Where n is 1 or 2 and m is 0 to 3, and when n is 1, m is 1 to 3. When n is 2, m is 1. X and Y respectively denote aryl or acen compounds of heterocyclic auxiliary ligands containing C or N, O, P, and B elements, respectively.
(2)

A pair of first and second electrodes;
And a light-emitting layer interposed between the first and second electrodes, the light-emitting layer generating excitons to extract light,
Wherein the light emitting layer comprises a metal complex compound represented by the following formula (1).
[Chemical Formula 1]

In Formula 1, M is a metal,
R1 to R4 of the main ligand are hydrogen (H), fluorine (F), alkyl, alkenyl, alkynyl, alkylaryl, cyano group (CN), fluorocarbon (CnF2n + 1; ), Trifluorovinyl, aryl, heteroaryl, substituted aryl, substituted heteroaryl, heterocyclic, CO2R, C (O) R and OR wherein R is a C1 to C20 alkyl group ,
An ancillary ligand is selected by using one of the following formula (2). Where n is 1 or 2 and m is 0 to 3, and when n is 1, m is 1 to 3. When n is 2, m is 1. X and Y respectively denote aryl or acen compounds of heterocyclic auxiliary ligands containing C or N, O, P, and B elements, respectively.
(2)

3. The method of claim 2,
Further comprising a hole injection layer and a hole transport layer disposed between the first electrode and the light emitting layer, and an electron transport layer disposed between the second electrode and the light emitting layer.

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