JP2007246468A - Fluorene compound and organic electroluminescent element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorene compound having excellent optoelectronic characteristics, to provide an organic light-emitting material which contains the fluorene compound and can emit light in high efficiency, high brightness and high life, and to provide an organic electroluminescent element. <P>SOLUTION: This fluorene compound represented by a chemical formula (A). The organic electroluminescent element containing the fluorene compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel fluorene compound that can be used as an organic light-emitting element material, a light-emitting material using the fluorene compound, an organic electroluminescent element, and a light-emitting element printing ink.

  In recent years, research on organic electroluminescent devices has been actively conducted. The organic electroluminescent element emits light with high luminance at a low applied voltage, and can be made into a thin and light-emitting device. Therefore, application to a next generation display is expected.

  In order to realize a high-performance full-color display, it is necessary to improve the characteristics of the light emitting elements of the three primary colors (red, blue, and green) constituting the high-performance full-color display. Among the three primary colors, blue greatly affects the power consumption and life of the entire display, and thus the blue light-emitting material needs to have excellent optoelectronic properties.

  Fluorene is one of the most promising blue light emitting materials, with efficient electroluminescence, optoelectronic properties such as high carrier mobility, temperature stability, chemical stability, good solubility in various solvents, excellent film Demonstrate the ability to form. Patent Document 1 discloses an oligofluorene compound and an organic light emitting device using the same.

JP 2003-55275 A

  An object of the present invention is to provide a fluorene compound having excellent optoelectronic properties, an organic light-emitting material containing the fluorene compound, and capable of high-efficiency, high-brightness and long-life light output, and an organic electroluminescent device. And

（式（Ａ）中、−Ｒ_１、−Ｒ_２は同一でも異なっていてもよく、置換基を有していてもよいフェニル基、または置換基を有していてもよいナフチル基、−Ｒ_３〜−Ｒ_６は同一でも異なっていてもよく、臭素、塩素、フッ素、ヨウ素から選ばれるハロゲン原子；水素原子；置換基を有していてもよいアミン基；置換基を有していてもよいフェニル基から選ばれる）で示されることを特徴とする。 The fluorene compound according to claim 1, which has been made to achieve the above object, has the following chemical formula (A):

(In the formula (A), -R ₁ and -R ₂ may be the same or different, and may have a phenyl group which may have a substituent, or a naphthyl group which may have a substituent, -R ₃ to -R ₆ may be the same or different and are a halogen atom selected from bromine, chlorine, fluorine and iodine; a hydrogen atom; an amine group which may have a substituent; and a substituent. Selected from good phenyl groups).

（式（Ｂ）中、−Ｒ_３〜−Ｒ_６は同一でも異なっていてもよく、臭素、塩素、フッ素、ヨウ素から選ばれるハロゲン原子；水素原子；置換基を有していてもよいアミン基；置換基を有していてもよいフェニル基から選ばれる）で示されることを特徴とする。 The fluorene compound according to claim 2 has the following chemical formula (B):

(In the formula (B), -R ₃ to -R ₆ may be the same or different and are a halogen atom selected from bromine, chlorine, fluorine and iodine; a hydrogen atom; an amine group which may have a substituent. Selected from phenyl groups optionally having substituents).

Examples of the phenyl group optionally having a substituent constituting -R ₁ and -R ₂ include a phenyl group, an ortho-methylphenyl group, a meta-methylphenyl group, and a para-methylphenyl group. Examples of the naphthyl group that may have a group include a 1-naphthyl group and a 2-naphthyl group. Of these, -R ₁ and -R ₂ are more preferably a para-methylphenyl group and / or a 1-naphthyl group.

Examples of the amine group that may have a substituent that constitutes —R ₃ to —R ₆ include an amine group, a phenylamine group, and a diphenylamine group. As the phenyl group that may have a substituent, Includes a phenyl group and a 3,5-bis (trifluoromethyl) phenyl group. Among these, -R ₃ to -R ₆ are more preferably selected from a hydrogen atom, a bromine atom, a diphenylamine group, and a 3,5-bis (trifluoromethyl) phenyl group.

であることを特徴とする。 A fluorene compound according to a third aspect is the one according to the first aspect, wherein the formula (A) is represented by the following formula (1) or (2):

It is characterized by being.

のうちのいずれかであることを特徴とする。 The fluorene compound according to a fourth aspect is the one according to the second aspect, wherein the formula (B) is represented by the following formulas (3) to (6).

It is any one of these.

  A light emitting device material according to claim 5 contains the fluorene compound according to claim 1 or 2.

  The organic electroluminescent device according to claim 6 is an organic electroluminescent device having a light emitting layer between an electrode pair consisting of an anode and a cathode, wherein the light emitting layer is the fluorene according to claim 1. It is characterized by containing a compound.

  A light emitting device printing ink according to a seventh aspect is characterized in that the fluorene compound according to the first or second aspect is dissolved in a hydrocarbon-based organic solvent.

  The fluorene compounds represented by the above formulas (1) to (6) were synthesized for the first time by the present invention. Since the fluorene compound is excellent in temperature stability and chemical stability and has high optoelectronic properties, it can be suitably used as a light emitting device material.

  In addition, since the fluorene compound exhibits high solubility in organic solvents, particularly hydrocarbon-based organic solvents, it can be easily formed not only by a vacuum deposition method but also by a wet process such as an inkjet method. It is.

  The organic electroluminescent element using the light emitting element material emits light with high efficiency and high luminance even when the applied voltage is low. Therefore, it is useful for display materials, lighting materials, solar cells, field effect transistors, and the like.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

出発物質である２，７−ジブロモ−９−フルオレノンに粉末マグネシウムと２−ヨードビフェニルとを加えて、乾燥エーテルを溶媒として反応させ、（ｉ）で示した２，７−ジブロモ−９−（２'−ビフェニル）−９−フルオレノールを合成する。さらに塩酸と酢酸とを加えて脱水反応させると、（ｉｉ）で示した２，７−ジブロモ−９−（２，２'−ビフェニル）フルオレンが得られる。 As a preferred example of the fluorene compound, the compound represented by the chemical formula (3) is synthesized according to the following chemical reaction formula.

Powdered magnesium and 2-iodobiphenyl are added to the starting material 2,7-dibromo-9-fluorenone and reacted with dry ether as a solvent, and 2,7-dibromo-9- (2 Synthesize '-biphenyl) -9-fluorenol. Further, when hydrochloric acid and acetic acid are added to cause dehydration reaction, 2,7-dibromo-9- (2,2′-biphenyl) fluorene shown in (ii) is obtained.

Next, Sonogashira Coupling reaction is performed by adding phenylacetylene to (ii), and 2,7-di (phenylacetyl) -9- (2,2′-biphenyl) shown in (iii) Fluorene is synthesized as an intermediate product. Sonogashira Coupling uses triethylamine or triphenylamine as a solvent, copper iodide (Cul), tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ) or tris (dibenzylideneacetone) dipalladium as a solvent at room temperature. For 48 hours.

  Next, tetraphenylcyclopentadienone shown in (iv) is introduced into the intermediate product (iii). When diphenyl ether is used as a solvent and refluxed at 250 ° C. for 48 hours, a fluorene compound represented by the chemical formula (3) (molecular weight 1229.55) can be obtained.

The synthesized compounds can be confirmed and identified by proton nuclear magnetic resonance ( ¹ H NMR), carbon nuclear magnetic resonance ( ¹³ C NMR), and matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF-Ms). .

  The fluorene compounds represented by the chemical formulas (1), (2), (4), (5) and (6) can also be synthesized by the same reaction.

  The light emitting device material of the present invention contains the fluorene compound. The light emitting device material is preferably used as a constituent material of the light emitting layer or the electron transport layer of the organic electroluminescent device, but may be contained in a hole injection layer, a hole transport layer, an electron injection layer, or the like of the organic electroluminescent device. .

  The organic electroluminescent element of the present invention has a light emitting layer containing the fluorene compound between an anode and a cathode provided on a substrate.

  Although the formation method of the said light emitting layer is not specifically limited, It is preferable when it forms into a film by the apply | coating process, for example, printing methods, such as offset printing or inkjet printing, a spin coat method, sputtering method etc. are mentioned. Among these, the inkjet method is more preferable. Since the fluorene compound is dissolved in a hydrocarbon-based organic solvent, it can be easily converted into an ink. The light emitting layer may be formed by a vacuum deposition method or a molecular lamination method.

  As the substrate, for example, a transparent substrate such as a glass substrate or a quartz substrate, or an opaque substrate such as a metal substrate or a ceramic substrate can be used.

  The material of the anode is preferably a material having a large work function, for example, a simple metal such as gold, platinum, nickel, palladium, cobalt, selenium, vanadium; an alloy of these metals; tin oxide, zinc oxide, indium tin oxide. (ITO), and metal oxides such as zinc indium oxide. These anode materials may constitute an anode alone or may be used in combination.

  The material of the cathode is preferably a material having a small work function, for example, simple metals such as lithium, sodium, potassium, calcium, magnesium, aluminum, indium, silver, lead, tin, chromium; alloys of these metals It is done. These cathode materials may constitute a cathode alone or in combination.

In addition to the light emitting layer, the organic electroluminescent element may be provided with a layer such as a hole injection layer, a hole transport layer, a hole block layer, an electron injection layer, and an electron transport layer. These layers may be single layers or multilayers, and may be organic compound layers or inorganic layers. The organic electroluminescent element only needs to contain the fluorene compound in at least one of the layers existing between the anode and the cathode. Specifically, for example, copper phthalocyanine or 4,4-bis (3-methylphenylphenylamino) biphenyl (mTDATA) as the hole injection layer, and 4,4,4-tris (3-methylphenylphenylamino) as the hole transport layer. ) Triphenylamine (TPD), N, N′-bis (1-naphthyl) -N, N′-diphenylbenzidine (NPD), 2,9-dimethyl-4,7-diphenyl-1,10 as a hole blocking layer -Phenanthroline (basocuproin; BCP), bis (2-methyl-8-quinolinolate) (p-phenylphenolate) aluminum (BAlq), bathophen, aluminum tris 8-hydroxyquinoline (Alq ₃ ) or 1,3 as an electron transport layer , 5-Tris (1-phenyl-2-benzimidazolyl) benzene (T Bi) can be used.

  The ink for printing a light emitting device of the present invention is obtained by dissolving the fluorene compound in a hydrocarbon-based organic solvent. The organic solvent is not particularly limited as long as it dissolves the fluorene compound, but xylene and tetralin are particularly preferable. One of these organic solvents may be used alone, or a mixed solvent may be used. Further, the concentration of the fluorene compound in the ink is preferably 1 to 5 wt%, particularly preferably 2 wt%. The ink for printing a light emitting element may contain an additive such as a surfactant, an antifoaming agent, a leveling agent, and a thickener in addition to the fluorene compound.

  The light-emitting element printing ink of the present invention is preferably used when forming a layer of an organic electroluminescent element by a coating process such as an inkjet method.

  An example of synthesizing the fluorene compound of the present invention is shown in Synthesis Examples 1 and 2, and an example in which an organic electroluminescent element was produced using the obtained fluorene compound is shown in Example 1, respectively.

(Synthesis Example 1) Synthesis of fluorene compound A (compound represented by the above chemical formula (3)) (1-1) Synthesis of 2,7-dibromo-9- (2′-biphenyl) -9-fluorenol Three-necked flask Was added with 0.11 g (2.96 × 10 ⁻³ mol) of powdered magnesium and stirred under a nitrogen stream. 20 ml of dry ether was added thereto, and the mixture was further stirred. Then, 1.0 ml (5.92 × 10 ⁻³ mol) of 2-iodobiphenyl was slowly added dropwise while suppressing heat generation and stirred for 1 hour while heating. Thereafter, 1.0 g (4.44 × 10 ⁻³ mol) of 2,7-dibromo-9-fluorenone was slowly added and refluxed overnight. After refluxing overnight, the mixture was separated with ether / water to separate the ether layer, dried over magnesium sulfate, and concentrated under reduced pressure. Purification was carried out using a silica gel column (petroleum ether: dichloromethane = 8: 2), followed by concentration under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR. In addition, NMR spectrometer AVANCE400 (made by Nippon Bruker) was used for NMR measurement.
Yield (yield): 1.38 mg (95%)

¹ H NMR (CDCl ₃ ): δ = 7.66 (d, 2H, ArH), 7.36 (m, 4H, ArH), 7.28 (m, 6H, ArH), 2.42 (s, 1H, -OH)

(1-2) Synthesis of 2,7-dibromo-9- (2,2′-biphenyl) fluorene 2,7-dibromo-9- (2′-biphenyl) -9-fluorenol 1 obtained in 1-1 .38 g (2.80 × 10 ⁻³ mol) and 20 ml of acetic acid were placed in a round flask and refluxed. Thereto was added 0.2 ml of hydrochloric acid, and the mixture was further refluxed for 20 minutes. Thereafter, the temperature was returned to room temperature, and water was added and stirred. The product was suction filtered, purified using a silica gel column (petroleum ether: dichloromethane = 8: 2), and concentrated under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR and ¹³ C NMR.
Yield (yield): 1.17 mg (88%)

¹ H NMR (CDCl ₃ , 400.13MHz): δ = 6.63 (d, J = 7.6Hz, 2H, ArH), 6.76 (s, 2H, ArH), 7.07 (t, J = 7.6Hz, 2H, ArH), 7.33 (t, J = 7.6Hz, 2H, ArH), 7.40 (d, J = 8.0Hz, 2H, ArH), 7.58 (d, J = 8.0Hz, 2H, ArH), 7.77 (d, J = 7.6Hz , 2H, ArH)
¹³ C NMR (CDCl ₃ ): δ = 119.3, 120.4, 120.9, 123.0, 126.3, 127.0, 127.3, 130.1, 138.6, 140.7, 146.0

(1-3) Synthesis of 2,7-di (phenylacetyl) -9- (2,2′-biphenyl) fluorene 2,7-dibromo-9- (2,2′-biphenyl) obtained in 1-2 ) 0.5 g (1.05 × 10 ⁻³ mol) of fluorene, 0.46 ml (4.20 × 10 ⁻³ mol) of phenylacetylene, 8 mg (4.20 × 10 ⁻⁵ mol) of copper iodide, Triphenylamine 55 mg (2.10 × 10 ⁻⁴ mol) and triethylamine 12 ml were added and degassed for 30 minutes under a nitrogen stream. Thereafter, 29 mg of tris (dibenzylideneacetone) dipalladium (0) was added and reacted for 48 hours. After the reaction, the mixture was separated with ether / water to separate the ether layer, dehydrated with magnesium sulfate, and concentrated under reduced pressure. Purification was carried out using a silica gel column (petroleum ether: dichloromethane = 8: 2), followed by concentration under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR and ¹³ C NMR.
Yield (yield): 1.17 mg (88%)

¹ H NMR (CDCl ₃ , 400.13MHz): δ = 6.76 (d, J = 7.6Hz, 2H, ArH), 6.91 (s, 2H, ArH), 7.14 (t, J = 8.0Hz, 2H, ArH), 7.27 (m, 6H, ArH), 7.39 (m, 6H, ArH), 7.55 (d, J = 8.0Hz, 2H, ArH), 7.82 (dd, J = 8.0Hz, 4H, ArH)
¹³ C NMR (CDCl ₃ ): δ = 120.5, 120.6, 123.2, 123.5, 124.5, 127.7, 128.4, 128.6, 128.7, 131.9, 132.0, 141.5, 142.2, 148.1, 149.6

(1-4) Synthesis of 2,7-di (2,3,4,5,6-pentaphenylbenzene) -9- (2,2′-biphenyl) fluorene (compound represented by the chemical formula (3)) 0.26 g (2.12 × 10 ⁻³ mol) of 2,7-di (phenylacetyl) -9- (2,2′-biphenyl) fluorene obtained in 1-3 was placed in an eggplant type flask, To the mixture, tetraphenylcyclopentadienone and diphenyl ether were added and refluxed at 250 ° C. for 48 hours. After the reaction, the mixture was separated with ether / water to separate the ether layer, dehydrated with magnesium sulfate, and concentrated under reduced pressure. Purification was carried out using a silica gel column (petroleum ether: dichloromethane = 8: 2), followed by concentration under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR, ¹³ C NMR and MALDI-TOF-Ms. For measurement of MALDI-TOF-Ms, Voyager DE Pro (manufactured by PerSeptive Biosystems) was used.
Yield (Yield): 30 mg (13%)

¹ H NMR (CDCl ₃ , 400.13MHz): δ = 6.02 (d, J = 7.2Hz, 2H, ArH), 6.15 (s, 2H, ArH), 6.37 (d, J = 8.0Hz, 4H, ArH), 6.54 (t, J = 7.6Hz, 4H, ArH), 6.60 (m, 6H, ArH), 6.68 (d, J = 7.6Hz, 2H, ArH), 6.74 (m, 16H, ArH), 6.79 (m, 20H, ArH), 7.01 (t, J = 7.6Hz, 2H, ArH), 7.06 (d, J = 8.0Hz, 2H, ArH), 7.27 (t, J = 7.6Hz, 2H, ArH), 7.66 (d , J = 7.6Hz, 2H, ArH)
¹³ C NMR (CDCl ₃ ): δ = 65.7, 118.7, 119.7, 124.4, 125.4, 125.5, 126.7, 126.8, 126.9, 127.3, 127.8, 127.9, 130.3, 131.1, 131.6, 131.7, 140.3, 140.4, 140.5, 140.6, 140.8, 141.7, 147.5
MALDI-TOF-Ms (Dithranol): m / z = 1229.1, calculated for C ₉₇ H ₆₄ ; 1229.55

Synthesis Example 2 Synthesis of fluorene compound B (compound represented by the above chemical formula (1)) (2-1) Synthesis of 8,13-dibromo-tetraphenylcyclopentadienone 1,3-diphenylpropan-2-one 0.55 g (2.62 × 10 ⁻³ mol), 1.0 g (2.72 × 10 ⁻³ mol) of 1,2-di (p-bromophenyl) ethane-1,2-dione and hydroxylation 147 mg of potassium and 5 ml of ethanol were added, stirred under a nitrogen stream, and reacted at 80 ° C. for 5 minutes. After the reaction, the mixture was separated with ether / water to separate the ether layer, dehydrated with magnesium sulfate, and concentrated under reduced pressure. Purification was carried out using a silica gel column (petroleum ether: dichloromethane = 3: 1), followed by concentration under reduced pressure to obtain the desired product.
Yield (yield): 0.83 g (58%)

(2-2) Synthesis of 2,7-di (phenylacetyl) -9,9-di (p-methylphenyl) fluorene 2,7-dibromo-9,9-di (p-methylphenyl) fluorene 0.2 g (3.97 × 10 ⁻⁴ mol), 0.17 ml (1.59 × 10 ⁻³ mol) of phenylacetylene, 3 mg (1.59 × 10 ⁻⁵ mol) of copper iodide, and 20 mg of triphenylphosphine ( 7.94 × 10 ⁻⁵ mol) and 5 ml of triethylamine were added, and the mixture was deaerated for 30 minutes under a nitrogen stream. Thereafter, 3.6 mg of Pd (PPh ₃ ) ₄ was added and reacted for 48 hours. After the reaction, the mixture was separated with ether / water to separate the ether layer, dehydrated with magnesium sulfate, and concentrated under reduced pressure. Purification was performed using a silica gel column (petroleum ether: dichloromethane = 8: 2), and the mixture was concentrated under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR and ¹³ C NMR.
Yield (yield): 0.11 g (51%)

¹ H NMR (CDCl ₃ , 400.13MHz): δ = 2.20 (s, 6H, ArH), 7.04 (dd, J = 8.0Hz, 8H, ArH), 7.30 (m, 6H, ArH), 7.49 (m, 8H , ArH), 7.69 (d, J = 7.6Hz, 2H, ArH)
¹³ C NMR (CDCl ₃ ): δ = 21.3, 65.2, 120.7, 123.1, 123.6, 128.4, 128.5, 128.6, 128.7, 128.8, 129.5, 129.7, 131.6, 132.0, 133.0, 136.9, 139.9, 142.2, 142.4, 152.5

(2-3) 2,7-di (2,3,4,5,6-pentaphenylbenzene) -9,9-di (p-methylphenyl) fluorene (compound represented by the chemical formula (1)) Synthesis 0.12 g (2.01 × 10 ⁻⁴ mol) of 2,7-di (phenylacetyl) 9,9-di (p-methylphenyl) fluorene obtained in Synthesis 2-2 was placed in an eggplant type flask, 8,13-Dibromo-tetraphenylcyclopentadienone obtained in 2-1 and diphenyl ether were added thereto, and the mixture was refluxed at 250 ° C. for 48 hours. After the reaction, the mixture was separated with ether / water to separate the ether layer, dehydrated with magnesium sulfate, and concentrated under reduced pressure. Purification was carried out using a silica gel column (petroleum ether: dichloromethane = 8: 2), followed by concentration under reduced pressure to obtain the desired product. The resulting product was identified by ¹ H NMR, ¹³ C NMR and MALDI-TOF-Ms.
Yield (yield): 12 mg (3.8%)

¹ H NMR (CDCl ₃ , 400.13MHz): δ = 2.29 (s, 6H, -CH ₃ ), 7.06 (m, 27H, ArH), 7.30 (m, 9H, ArH), 7.48 (m, 18H, ArH) , 7.56 (d, J = 8.0Hz, 3H, ArH), 7.66 (d, J = 8.0Hz, 3H, ArH)
¹³ C NMR (CDCl ₃ ): δ = 122.0, 125.9, 127.7, 127.9, 128.1, 128.6, 129.3, 129.5, 130.1, 132.1, 136.4, 135.4, 135.9, 136.3, 142.4, 144.7
MALDI-TOF-Ms (Dithranol): m / z = 1575.53, calculated for C ₉₉ H ₆₆ Br ₄ ; 1575.20

(Example 1) Preparation of organic electroluminescent element A (EL element A) using fluorene compound A in the light emitting layer The element structure is ITO / NPD / Ir (ppy) ₃ + fluorene compound A / BCP / Alq ₃ / LiF. / Al.
On a glass substrate, ITO was formed into a film having a thickness of 150 nm by sputtering as an anode, and was successively subjected to ultrasonic cleaning and drying with a neutral detergent, an alkaline detergent, pure water, acetone, and isopropyl alcohol (IPA).

Next, N, N′-bis (1-naphthyl) -N, N′-diphenylbenzidine (NPD) is vacuum deposited on the electrode as a hole transport layer (degree of vacuum: 1.0 × 10 ⁻⁴ Pa). The film was formed at a film thickness of 40 nm at a film formation rate of 0.5 angstrom / second.

Next, a layer of the fluorene compound obtained in Synthesis Example 1 was formed as a light emitting layer on the hole transport layer. The fluorene compound and tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) were vapor-deposited at a ratio of 93: 7 by a vacuum vapor deposition method to form a film with a thickness of 25 nm. The film formation rate is 1.0 angstrom / second for the fluorene compound and 0.08 angstrom / second for Ir (ppy) ₃ .

  Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine; BCP) is formed as a hole blocking layer on the light emitting layer by a vacuum deposition method at a film forming rate of 0.5 angstrom / second. The film was formed with a thickness of 10 nm.

Next, aluminum tris 8-hydroxyquinoline (Alq ₃ ) was formed as an electron transporting layer on the hole blocking layer by a vacuum deposition method at a film forming rate of 0.5 angstrom / second to a film thickness of 20 nm.

  Next, lithium fluoride (LiF) and aluminum (Al) were deposited on the electron transport layer as a cathode. Lithium fluoride was deposited at a film thickness of 0.5 nm at a deposition rate of 0.1 angstrom / second by vacuum deposition, and then aluminum was deposited at a deposition rate of 1-5 angstrom / second by vacuum deposition. An EL element A was fabricated by forming a film with a thickness of 200 nm per second.

To the resulting EL device A, ITO anode, a green light emitting phosphorescence from the LiF-Al a when applying a DC voltage at 10V as the cathode 2500 cd ^/ m 2, 16V at 40000 cd / ^{m 2} of Ir _{(ppy) 3} is Observed.

(Example 2) Production of organic electroluminescence device B (EL device B) using fluorene compound A in the light emitting layer The device configuration was ITO / PEDOT-PSS / Ir (ppy) ₃ + fluorene compound A / BCP / Alq ₃ / LiF / Al.
On a glass substrate, ITO was formed into a film having a thickness of 150 nm by sputtering as an anode, and was successively subjected to ultrasonic cleaning and drying with a neutral detergent, an alkaline detergent, pure water, acetone, and isopropyl alcohol (IPA).

  Next, a poly (3,4-ethylenedioxythiophene) -poly (4-styrenesulfonate) (PEDOT-PSS) layer, which is a conductive polymer, was formed as a hole transport layer on the anode. PEDOT-PSS (Baytron P AI4083) was formed into a film with a film thickness of 50 nm by spin coating (2000 rpm), dried at 180 ° C., and baked.

Next, a layer of the fluorene compound obtained in Synthesis Example 1 was formed as a light emitting layer on the hole transport layer. The fluorene compound and tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) are dissolved in ortho-dichlorobenzene at a ratio of 93: 7 to prepare a 2 wt% solution, and spin coating after filtering A film was formed at a film thickness of 40 nm at 2000 rpm, dried and baked at 160 ° C.

  Next, BCP was formed as a hole blocking layer on the light emitting layer with a film thickness of 10 nm at a film forming rate of 0.5 angstrom / second by a vacuum deposition method.

Next, Alq ₃ was deposited as an electron transport layer on the hole block layer by a vacuum deposition method at a deposition rate of 0.5 angstrom / second to a thickness of 20 nm.

  Next, lithium fluoride and aluminum were deposited on the electron transport layer as a cathode. Lithium fluoride was deposited at a film thickness of 0.5 nm at a deposition rate of 0.1 angstrom / second by vacuum deposition, and then aluminum was deposited at a deposition rate of 1-5 angstrom / second by vacuum deposition. An EL element B was manufactured by forming a film with a thickness of 200 nm per second.

  The following measurements were performed on the fluorene compound obtained in Synthesis Example 1 and the EL device A produced in Example 1, and the physical properties were evaluated.

(Fluorescence spectrum measurement)
A sample obtained by dissolving the fluorene compound obtained in Synthesis Example 1 in chloroform was used as a sample. The fluorescence spectrum of the sample was measured at λex = 310, 355, 330, and 340 nm using a fluorometer FP-750ST (manufactured by JASCO Corporation). The measurement results are shown in FIG.

(Measurement of current density, light emission luminance, light emission efficiency, light emission intensity)
Using EL1003 (manufactured by Precise Gauge), the current density, light emission luminance, light emission efficiency, and light emission intensity of the EL device produced in Example 1 were measured. Each measurement result is shown in FIGS.

  As is clear from FIG. 1, the fluorene compound of Synthesis Example 1 exhibited excellent fluorescence characteristics. Further, as is clear from FIGS. 2 to 5, the EL elements of the examples had good light emission luminance, light emission efficiency, and light emission intensity, and had excellent electroluminescence characteristics.

  From the above results, it was confirmed that the fluorene compound of the present invention is useful as an EL device material.

  Further, the fluorene compound of the present invention was well dissolved in an organic solvent such as dichlorobenzene, and film formation by a coating process could be easily performed.

  Similar results were obtained for the fluorene compounds represented by the chemical formulas (1), (2), (4), (5), and (6).

2 is a fluorescence spectrum of a fluorene compound obtained in Synthesis Example 1. FIG.

2 is a graph obtained by measuring the current density of an EL element manufactured in Example 1. FIG.

2 is a graph obtained by measuring light emission luminance of an EL element manufactured in Example 1. FIG.

2 is a graph obtained by measuring the light emission efficiency of the EL element manufactured in Example 1. FIG.

2 is a graph obtained by measuring light emission intensity of an EL element manufactured in Example 1. FIG.

Claims (7)

The following chemical formula (A)

(In the formula (A), -R ₁ and -R ₂ may be the same or different, and may have a phenyl group which may have a substituent, or a naphthyl group which may have a substituent, -R ₃ to -R ₆ may be the same or different and are a halogen atom selected from bromine, chlorine, fluorine and iodine; a hydrogen atom; an amine group which may have a substituent; and a substituent. A fluorene compound selected from the group consisting of a good phenyl group. The following chemical formula (B)

(In the formula (B), -R ₃ to -R ₆ may be the same or different and are a halogen atom selected from bromine, chlorine, fluorine and iodine; a hydrogen atom; an amine group which may have a substituent. Selected from phenyl groups optionally having substituents). The formula (A) is represented by the following formula (1) or (2)

The fluorene compound according to claim 1, wherein The formula (B) is represented by the following formulas (3) to (6).

The fluorene compound according to claim 2, which is any one of the above.   A light emitting device material comprising the fluorene compound according to claim 1.   An organic electroluminescence device having a light emitting layer between an electrode pair consisting of an anode and a cathode, wherein the light emitting layer contains the fluorene compound according to claim 1 or 2. element.   An ink for printing a light-emitting element, wherein the fluorene compound according to claim 1 is dissolved in a hydrocarbon-based organic solvent.

Images