WO2009148269A2 - Benzofluoranthene derivative and an organic luminescent element employing the same - Google Patents

Abstract

The present invention relates to a benzofluoranthene derivative and to an organic electroluminescent element employing the same. More specifically, the present invention relates to a benzofluoranthene derivative comprising one or more substituent groups selected from the benzimidazole group, the benzothiazole group and the benzoxazole group, which are substituent groups having an electron-transfer ability. The present invention also relates to an organic luminescent element comprising an organic layer containing this benzofluoranthene derivative.

Description

Benzofluoranthene derivatives and organic light emitting device using the same

The present invention relates to a novel benzofluoranthene derivative and an organic electroluminescent device using the same. More specifically, a benzimidazole group, a benzothiazole group, The present invention relates to an organic light emitting device including a benzofluoranthene derivative including at least one substituent selected from the group consisting of benzoxazole groups, and an organic material layer containing the benzofluoranthene derivative.

In general, organic light emitting phenomenon refers to a phenomenon in which light appears when electric energy is applied to an organic material. That is, when the organic material layer is positioned between the anode and the cathode and a voltage is applied between the two electrodes, electrons and holes are injected and an excited state of the organic material is generated. The excited carrier then returns to its original stable state and emits the unique light of the material itself.

In the 1950s, Bernanose applied luminescence from an organic thin film by applying a high alternating voltage to a polymer thin film containing an organic dye.In 1965, singlet excitons were generated by applying a current to anthracene single crystal to generate blue fluorescence. Got.

Since then, as a way to effectively make the organic light emitting device has been studied to manufacture the organic material layer in a multi-layer structure. Most organic light emitting devices used in the present invention include a hole injection layer that receives holes from a substrate, an anode, and an anode, a hole transport layer for transferring holes, a light emitting layer for recombining holes and electrons to emit light, an electron transport layer for transferring electrons, It consists of an electron injection layer and a cathode which receive an electron from a cathode. The reason why the EL device is manufactured in multiple layers is that the movement speeds of the holes and the electrons are different. Therefore, if the appropriate hole injection layer, the transport layer, the electron transport layer, and the electron injection layer are made, holes and electrons can be effectively transferred. This is because the light emission efficiency can be improved by balancing the electrons.

The earliest reports on the material of electron transport include oxadiazole derivatives (PBDs). It has since been reported that triazole derivatives (TAZ) and phenanthroline derivatives (BCP) exhibit electron transport properties. As organic monomolecular materials for electron transport, organometallic complexes having excellent electron stability and electron transport speed are good candidates. Among them, Alq3 having an electron mobility greater than hole mobility is reported to be the best candidate. When used in the device, there is a problem that the color purity is lowered due to light emission due to exciton diffusion. In addition, conventionally known materials for electron transport include flavon derivatives published by Sanyo or Germanium and silicon cyclopentadiene derivatives from Chiso. (Japanese Laid-Open Patent Publication No. 1998-017860, Japanese Laid-Open Patent Publication No. 1999-087067).

In addition, many organic monomolecular substances having imidazole group, oxazole group, or thiazole group have been reported as materials for conventional electron injection and transport. However, before these materials were reported as electron transport materials, it was previously reported in Motorola EU 0700917 A2 that metal complex compounds of these materials were applied to a blue light emitting layer or a cyan light emitting layer of an organic light emitting device.

TPBI, published by Kodak in 1996 and described in US Pat. No. 5,645,948, is known as a representative electron transporting material having an imidazole group, and its structure is three N-phenyl benz at 1,3,5 substitution position of benzene. It contains an imidazole group and functionally blocks electrons from the light emitting layer as well as its ability to transfer electrons, but has a problem of low thermal stability for practical application.

In addition, the electron transport materials disclosed in Japanese Patent Application Laid-Open No. 11-345686 report that they contain oxazole groups and thiazole groups and can be applied to the light emitting layer, but have reached practical use in terms of driving voltage, luminance, and lifetime of the device. I can't.

Therefore, in order to overcome the problems of the prior art as described above and further improve the characteristics of the organic light emitting device, development of a more stable and efficient material that can be used as an electron transporting material in the organic light emitting device is continuously required.

An object of the present invention is to provide a novel compound which is substituted with a substituent having an electron transfer capability to benzofluoranthene, which can be applied to an organic light emitting device to improve luminous efficiency, stability and device life. .

Moreover, an object of this invention is to provide the organic light emitting element using the said compound.

The present invention provides a compound represented by the following formula (1). The compound represented by the following formula (1) is a benzofluoranthene derivative.

[Formula 1]

In formula 1, X is selected from the group consisting of NR ⁶ , S and O;

R ¹ to R ⁶ are the same as or different from each other, and are each independently H, a C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group , C ₃ ~ C ₄₀ heterocycloalkyl group, C ₆ ~ C ₄₀ arylalkyl group, C ₁ ~ C ₄₀ alkyloxy group, C ₅ ~ C ₄₀ aryloxy group, C ₅ ~ C ₄₀ aryl group and C ₅ to C ₄₀ heteroaryl group;

A is selected from the group consisting of single bond, heteroarylene, C ₅ ~ C ₄₀ arylene group and a C ₅ ~ C ₄₀ of.

The present invention also provides an organic light emitting device comprising (i) an anode, (ii) a cathode, and (iii) one or more organic material layers interposed between the anode and the cathode.

At least one organic material layer of the one or more organic material layer provides an organic light emitting device characterized in that it comprises a compound represented by the formula (1).

In the organic light emitting device of the present invention, the organic material layer including the compound represented by Formula 1 is preferably an electron transport layer.

Since the compound represented by Chemical Formula 1 according to the present invention has excellent electron transporting performance, the compound represented by Chemical Formula 1 exhibits superior performance in terms of voltage and efficiency than when Alq3 is used as the electron transporting layer material of the organic light emitting device. Therefore, the compound represented by Chemical Formula 1 according to the present invention can greatly contribute to improving EL performance and lifespan of an organic EL device. In particular, the improvement of electron transport performance has a great effect on maximizing performance in a full color organic EL panel.

1 is a cross-sectional view showing an example of an organic light emitting device structure according to the present invention;

2 is a TGA graph of Inv-14 prepared in Example 2;

3 is a TGA graph of Alq3, a known material.

Compound represented by the formula (1) according to the present invention is a benzofluoranthene (benzofluoranthene) as a core, a benzimidazole group, a benzothiazole group and a benzoxazole as a substituent having an electron transfer ability It is a benzofluoranthene derivative characterized by including one or more substituents selected from (benzoxazole) groups.

More specifically, the compound represented by Chemical Formula 1 has a structure in which benzofluoranthene is the core, and a benzimidazole group, a benzothiazole group, or a benzoxazole group is substituted at the third carbon position of the benzofluoranthene. It is characteristic to have.

In addition, in the compound represented by Formula 1 according to the present invention, the benzofluoranthene moiety (C) is an alkyl group of C ₁ ~ C ₄₀ , C ₂ ~ C ₄₀ alkenyl group, C ₂ ~ C in addition to a hydrogen atom ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group, C ₃ to C ₄₀ heterocycloalkyl group, C ₆ to C ₄₀ arylalkyl group, C ₁ to C ₄₀ alkyloxy group, C ₅ to C ₄₀ aryl One or more substituents selected from the group consisting of an oxy group, a C ₅ to C ₄₀ aryl group and a C ₅ to C ₄₀ heteroaryl group may be introduced.

In addition, in the compound represented by Formula 1 according to the present invention, the benzimidazole group, benzothiazole group and benzoxazole group are each independently C ₁ ~ C ₄₀ Alkyl group, C ₂ ~ C ₄₀ Alkenyl group, C ₂ ~ C ₄₀ alkynyl group, C ₃ ~ C ₄₀ cycloalkyl group, C ₃ ~ C ₄₀ heterocycloalkyl group, C ₆ ~ C ₄₀ aryl group, C ₁ ~ alkyloxy group of C ₄₀ of the, C ₅ ~ C ₄₀ At least one substituent selected from the group consisting of an aryloxy group, a C ₅ ~ C ₄₀ aryl group and a C ₅ ~ C ₄₀ heteroaryl group may be substituted.

In the compound represented by Formula 1 according to the present invention, A is selected from the group consisting of single bond, heteroarylene, C ₅ ~ C ₄₀ arylene group and a C ₅ ~ C ₄₀ of. Examples of the C ₅ to C ₄₀ arylene group and the C ₅ to C ₄₀ heteroarylene group of A are as follows, but are not limited thereto.

 In more detail, the compound represented by Formula 1 according to the present invention is the same as those of Table 1 below, but the compounds according to the present invention are not limited to those illustrated below.

Table 1

 Of the compounds exemplified above, the following materials show good properties, but are not limited thereto.

The method for preparing the compound represented by Chemical Formula 1 according to the present invention is not particularly limited, and reactions known in the art may be appropriately applied.

The present invention provides an organic light emitting device comprising (i) an anode, (ii) a cathode, and (iii) at least one organic layer interposed between the anode and the cathode, wherein at least one of the at least one organic layer The organic material layer provides an organic light emitting device comprising the compound represented by Chemical Formula 1. In this case, the compound represented by Formula 1 may be used one kind or two or more kinds.

In addition, in the organic light emitting device of the present invention, the compound represented by Chemical Formula 1 may be included as a material for an electron transport layer, in which case the luminous efficiency, stability and device life of the organic light emitting device can be improved. Therefore, the organic material layer including the compound represented by Formula 1 is preferably an electron transport layer.

In addition, in the organic light emitting device of the present invention, an organic material layer other than the organic material layer including the compound represented by Formula 1 of the present invention may be a hole injection layer, a hole transport layer, a light emitting layer, and / or an electron transport layer.

1 is a cross-sectional view showing an example of an organic light emitting device structure according to the present invention, wherein the substrate 101, the anode 102, the hole injection layer 103, the hole transport layer 104, the light emitting layer 105, the electron transport layer ( 106 and the cathode 107 are sequentially stacked. In this case, the electron transport layer includes a compound represented by Chemical Formula 1. The electron injection layer may be positioned on the electron transport layer 106.

As described above, the organic light emitting device of the present invention may not only have a structure in which an anode, one or more organic material layers, and a cathode are sequentially stacked, but an insulating layer or an adhesive layer may be inserted at an interface between the electrode and the organic material layer.

In the organic light emitting device of the present invention, the organic material layer including the compound represented by Chemical Formula 1 may be formed by a vacuum deposition method or a solution coating method, but is not limited thereto.

The organic light emitting device of the present invention uses an organic material layer and an electrode using materials and methods known in the art, except that one or more organic material layers of the organic material layer are formed to include the compound represented by Chemical Formula 1 of the present invention. By forming.

For example, the substrate 101 may be a silicon wafer, quartz or glass plate, metal plate, plastic film or sheet.

The anode 102 material may be a metal such as vanadium, chromium, copper, zinc, gold or an alloy thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO); Combinations of metals and oxides such as ZnO: Al or SnO ₂ : Sb; Conductive polymers such as polythiophene, poly (3-methylthiophene), poly [3,4- (ethylene-1,2-dioxy) thiophene] (PEDT), polypyrrole and polyaniline; Or carbon black, but is not limited thereto.

Cathode materials include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead or alloys thereof; Multilayer structure materials such as LiF / Al or LiO ₂ / Al, and the like, but are not limited thereto.

In addition, the hole injection layer 103, the hole transport layer 104 and the light emitting layer 105 is not particularly limited, conventional materials known in the art may be used.

Hereinafter, the present invention will be described in detail with reference to the following Examples. However, the following examples are merely to illustrate the present invention and the present invention is not limited by the following examples.

Example 1 Synthesis of Compound Represented by Inv-1

Example 1-1

14.07 g (92.48 mmol) of acenaphthylene and 25 g (92.48 mmol) of diphenylisobenzofuran were dissolved in 200 ml of xylene and stirred under reflux for 7 hours. After installing the ice bath, ether 1200 ml was added at 0 ° C. and stirred for 1 hour. The resulting solid was filtered to give 25 g of compound a (yield = 62.8%).

¹ H NMR (500MHz, THF-d8): 7.46 (d, 6H), 7.37 (t, 2H) 7.31 (t, 6H), 7.11 (d, 2H), 7.01 (d, 2H), 6.93 (t, 2H ), 4.41 (s, 2 H)

Example 1-2

24.5 g (58.03 mmol) of Compound a synthesized in Example 1-1 were dissolved in 171.5 ml of acetic acid. 17.15 ml of 48% HBr was slowly added dropwise to the reaction solution. The final reaction solution was stirred at reflux for 3 hours. The resulting solid was filtered to give 22.19 g of compound b (yield = 96.7%).

¹ H NMR (500MHz, THF-d8): 8.55 (d, 2H), 7.90 (d, 2H) 7.79 (d, 2H), 7.65 (d, 4H), 7.58 (t, 2H), 7.48 (m, 6H ), 7.32 (t, 2 H)

Example 1-3

22.19 g (54.86 mmol) of Compound b and 12.4 g (54.86 mmol) of N-bromosuccinimide obtained in Example 1-2 were dissolved in 250 ml of chloroform, followed by stirring under reflux. Column chromatography gave the compound c 23 g (yield = 86%).

¹ H NMR (500MHz, THF-d8): 8.55 (d, 2H), 8.53 (d, 1H) 8.14 (d, 1H), 7.76 (d, 1H), 7.65 (d, 4H), 7.57 (t, 1H ), 7.46 (m, 6H), 7.45 (d, 1H), 7.32 (t, 2H)

Example 1-4

40 g (216.2 mmol) of 3-bromobenzaldehyde and 39.82 g (216.2 mmol) of N-phenyl-1,2-phenylene diamine were dissolved in 500 ml of toluene and 150 ml of acetic acid for 30 hours. Stirred at reflux. After cooling the final reaction product to room temperature, the solvent was removed by distillation under reduced pressure. Purification by column chromatography (Hex: EA: TEA = 9: 1: 1 (v: v: v)) afforded 40.16 g of compound d (yield = 26.5%).

¹ H NMR (500MHz, THF-d8): 8.56 (d, 1H), 7.81 (d, 1H) 7.65 (s, 1H), 7.55 (t, 2H), 7.53 (t, 1H), 7.42 (d, 1H ), 7.39 (d, 1H), 7.30 (d, 2H), 7.28 (t, 1H), 7.21 (t, 2H)

Example 1-5

40.16 g (115.0057 mmol) of Compound d obtained in Examples 1-4, 4.2 g of Pd (dppf) Cl ₂ , 35.1 g (138.0068 mmol) of Bis (pinacolato) diboron and 33.86 g (345.0171 mmol) of potassium acetate were prepared in 1,4 -Dissolved in 250 ml of dioxane. The reaction was stirred under reflux for 6 hours, and then extracted three times with dichloromethane and distilled water. Purification by column chromatography (Hex: EA = 9: 1 (v: v)) afforded 39 g of compound e (yield = 86%).

¹ H NMR (500MHz, THF-d8): 8.56 (d, 1H), 7.81 (d, 1H) 7.55 (m, 5H), 7.30 (m, 3H), 7.28 (t, 1H), 7.21 (m, 2H ), 1.26 (s, 12 H)

Example 1-6

10.5 g (21.7373 mmol) of the compound c obtained in Example 1-3 and 9.5 g (23.9110 mmol) of the compound e synthesized in Example 1-5 were added thereto, and the mixture was stirred under reflux for 18 hours. Extraction with dichloromethane and column chromatography with Hexane: MC = 9: 1 (v: v) gave 11 g (yield = 75%) of Inv-1 as a target compound.

¹ H NMR (500MHz, THF-d8): 7.21 (t, 1H), 7.28 (t, 1H) 7.3 (d, 2H), 7.32 (t, 2H), 7.38 (t, 2H), 7.44 (d, 2H ), 7.5 (t, 4H), 7.52 (t, 2H), 7.54 (t, 1H), 7.57 (t, 2H), 7.60 (d, 2H), 7.65 (d, 4H), 7.70 (s, 1H) , 7.81 (d, 1H), 8.42 (d, 1H), 8.51 (d, 1H), 8.55 (d, 2H), 8.70 (d, 1H).

Example 2 Synthesis of Compound Represented by Inv-14

Example 2-1

20 g (89.66 mmol) of 6-bromo-2-naphthol, 27.3 g (107.59 mmol) of Bis (pinacolato) diboron, and 26.4 g (268.97 mmol) of potassium acetate were suspended in 400 ml of 1,4-dioxane. ₂ g (2.69 mmol) of Pd (dppf) Cl ₂ [1,1'-Bis (diphenylphosphino) ferrocene] dichloropalladium (II) was added to the solution. The reaction mixture was stirred under reflux for 5 hours, extracted three times with dichloromethane and distilled water, and then subjected to column chromatography (Hex: EA = 8: 1 (v: v)) to obtain a compound f of 19.6 g (yield = 80.9%). )

¹ H NMR (500MHz, THF-d8): 7.88 (d, 1H), 7.60 (s, 1H) 7.50 (d, 1H), 7.30 (d, 1H), 7.00 (m, 2H), 1.26 (s, 12H )

Example 2-2

15 g (31.05 mmol) of compound c synthesized in Example 1-2 and 9.23 g (34.16 mmol) of compound f synthesized in Example 2-1, 1.1 g (0.93 mmol) of Pd (PPh ₃ ) ₄ and sodium carbonate (sodium carbonate) 9.87 g (93.16 mmol) was suspended in 300 ml of toluene and 100 ml of distilled water, followed by stirring under reflux for 6 hours. After completion of the reaction was extracted with dichloromethane and distilled water and purified by column chromatography (Hex: EA = 9: 1 (v: v)) to give a compound g 10.5 g (yield = 62%).

¹ H NMR (500MHz, THF-d8): 8.55 (d, 2H), 7.90 (d, 2H) 7.79 (m, 4H), 7.65 (m, 6H), 7.58 (t, 2H), 7.48 (t, 2H ), 7.46 (t, 4H), 7.32 (t, 2H), 6.98 (m, 1H).

Example 2-3

10 g (18.29 mmol) of the compound g synthesized in Example 2-2 was dissolved in 400 ml of dichloromethane. 2.17 g (27.44 mmol) of pyridine was added to the reaction solution, and stirred for 1 hour. Then, 6.19 g (21.95 mmol) of trifluoromethanesulfonic anhydride was slowly added under nitrogen at 0 ° C., and the reaction mixture was stirred at room temperature for 4 hours. After completion of the reaction, the reaction was completed by TLC. After completion of the reaction, the organic layer was extracted with distilled water, and the organic layer was distilled under reduced pressure to remove the solvent, followed by chromatography using Hex: Methylene Chloride = 4: 1 (v: v) solution. Compound h 11 g (yield = 88%) as a yellow solid was obtained.

¹ H NMR (500MHz, THF-d8): 8.55 (d, 2H), 8.51 (d, 1H) 7.88 (d, 1H), 7.78 (d, 2H), 7.65 (d, 4H), 7.60 (d, 2H ), 7.54 (s, 1H), 7.48 (t, 6H), 7.40 (d, 2H), 7.32 (d, 2H), 6.98 (m, 2H).

Example 2-4

Compound h 11 g (16.21 mmol) synthesized in Example 2-3 and 6.49 g (16.21 mmol) of compound e synthesized in Example 1-5, 0.56 g (0.49 mmol) of Pd (PPh3) 4, and sodium carbonate ( sodium carbonate) was suspended in 200 ml of toluene and 40 ml of distilled water, followed by stirring under reflux for 5 hours. After completion of the reaction, the mixture was extracted with dichloromethane and distilled water, the organic layer was dried and distilled under reduced pressure to remove the solvent, and then chromatographed using Hex: Methlyene Chloride = 4: 1 (v: v) solution to give the product as a yellow solid. 14 10 g (yield = 77%) were obtained.

¹ H NMR (500MHz, THF-d8): 7.21 (t, 1H), 7.3 (d, 2H), 7.32 (t, 2H), 7.38 (t, 1H), 7.28 (t, 1H), 7.44 (d, 2H), 7.46 (t, 4H), 7.48 (t, 2H), 7.53 (t, 1H), 7.55 (t, 2H), 7.58 (m, 3H), 7.65 (d, 4H), 7.70 (s, 1H ), 7.73 (d, 2H), 7.80 (d, 1H), 7.81 (d, 1H), 7.92 (d, 2H), 7.99 (m, 3H), 8.56 (d, 3H).

[Examples 3 to 4 and Comparative Example 1] Fabrication of Organic Light-Emitting Device

The glass substrate coated with ITO (Indium tin oxide) having a thickness of 1500 Å was washed with distilled water ultrasonic waves. After the washing of distilled water, ultrasonic washing with a solvent such as isopropyl alcohol, acetone, methanol, and the like was dried and transferred to a plasma cleaner, and then the substrate was cleaned for 5 minutes using an oxygen plasma, and then the substrate was transferred to a vacuum depositor.

DS-205 (Doosan Corp.) was vacuum-deposited to a thickness of 600 kPa on the prepared ITO transparent electrode to form a hole injection layer. NPB, which is a material for transporting holes, was deposited thereon to form a hole transport layer, and then DS-H45 (Doosan) and DS-405 (Doosan), which acted as light emitting layers, were deposited at 300Å.

Compound Inv-1 prepared in Example 1 (Example 3), Compound Inv-14 prepared in Example 2 (Example 4), or Comparative material Alq3 ( Comparative Example 1) was deposited to a thickness of 250 mm 3.

Thereafter, LiF, an electron injection material, was deposited to a thickness of 10 mW, and aluminum (cathode) was deposited to a thickness of 2000 mW to fabricate an organic light emitting device.

The organic light emitting diode structures of Examples 3 and 4 are listed in Table 2, and the organic light emitting diode structures of Comparative Example 1 are described in Table 3. In addition, the properties of the organic light emitting device of Example 3 are described in Table 4, the properties of the organic light emitting device of Example 4 are described in Table 5, and the properties of the organic light emitting device of Comparative Example 1 are described in Table 6 below. It was.

TABLE 2

TABLE 3

Table 4

Table 5

Table 6

As described above, organic light emitting diodes (Examples 3 and 4) using the compound according to the present invention exhibited superior performance in terms of voltage and efficiency than organic light emitting diodes (Comparative Example 1) using Alq3. I could confirm it.

2 is a TGA graph of Inv-14, an electron transporting compound prepared in Example 2, and FIG. 3 is a TGA graph of Alq3, a known electron transporting material. According to FIGS. 2 and 3, the Td value of Inv-14 of the present invention is about 80 ° C. higher than that of Alq3, and accordingly, the compound of the present invention can be used to improve the thermal characteristics of the device.

Therefore, the compounds according to the present invention may not only improve the EL performance of the organic EL device, but also greatly contribute to the improvement of the lifetime. In particular, the improvement of the electron transport performance is expected to have a great effect in maximizing the performance in the full color organic EL panel.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Claims (3)

1. Compound represented by the following formula (1):

   [Formula 1]

   

   In formula 1, X is selected from the group consisting of NR ⁶ , S and O;

   R ¹ to R ⁶ are the same as or different from each other, and are each independently H, a C ₁ to C ₄₀ alkyl group, C ₂ to C ₄₀ alkenyl group, C ₂ to C ₄₀ alkynyl group, C ₃ to C ₄₀ cycloalkyl group , C ₃ ~ C ₄₀ heterocycloalkyl group, C ₆ ~ C ₄₀ arylalkyl group, C ₁ ~ C ₄₀ alkyloxy group, C ₅ ~ C ₄₀ aryloxy group, C ₅ ~ C ₄₀ aryl group and C ₅ to C ₄₀ heteroaryl group;

   A is selected from the group consisting of single bond, heteroarylene, C ₅ ~ C ₄₀ arylene group and a C ₅ ~ C ₄₀ of.
2. An organic light emitting device comprising (i) an anode, (ii) a cathode, and (iii) at least one organic layer interposed between the anode and the cathode,

   At least one organic material layer of the one or more organic material layer comprises an compound represented by the formula (1) of claim 1.
3. The organic light emitting device of claim 2, wherein the organic material layer including the compound represented by Chemical Formula 1 is an electron transport layer.

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