O-phenanthroline derivative, organic electroluminescent device and display or lighting device

Abstract

The present invention provides an o-phenanthroline derivative, an organic electroluminescent device, and a display or lighting device. At least one of a charge generation layer and an electron transport layer in the organic electroluminescent device comprises an o-phenanthroline derivative, wherein the o-phenanthroline derivative is represented by the following formula 1: #imgabs0# The organic electroluminescent device of the present invention has excellent luminous efficiency and reduced driving voltage.

Description

Technical Field

[0001] The present invention relates to an o-phenanthroline derivative, and more particularly to an o-phenanthroline derivative and an organic electroluminescent device comprising the same. Background Art

[0002] Light-emitting devices (ELDs) are devices that convert electrical energy into light using organic materials. They contain a structure with a light-emitting organic layer between an anode and a cathode. EL devices can have a variety of structures, and research has focused on tendon-type EL devices, where multiple light-emitting units are stacked. In tendon-type EL devices, light-emitting units containing light-emitting layers are stacked between an anode and a cathode.

[0003] There is a charge generation layer between adjacent light-emitting parts for the generation and movement of charges.

[0004] The charge generation layer requires low driving voltage and high efficiency. Summary of the Invention

[0005] The object of the present invention is to provide an o-phenanthroline derivative, wherein an organic electroluminescent device comprising the derivative has excellent efficiency and low driving voltage. In order to achieve the object of the present invention, the technical solution of the present invention is as follows:

[0006] The present invention provides a phenanthroline derivative, the structural formula of which is shown in Formula 1:

[0007]

[0008] wherein Ar1 and Ar2 are each independently selected from substituted or unsubstituted C12-C30 phenanthroline derivatives,

[0009] The o-phenanthroline derivative is represented by any one of the following formulae 1-1 to 1-6:

[0010]

[0011] Among them, R1 to R 16 Each is independently selected from substituted or unsubstituted hydrogen, deuterium, halogen, alkyl, C6-C30 aryl and C5-C30 heteroaryl;

[0012] L is selected from a single bond, a substituted or unsubstituted C5-C30 pyridyl group.

[0013] Preferably, the o-phenanthroline derivative is any one of the following:

[0014]

[0015]

[0016] The present invention further provides an organic electroluminescent device, comprising:

[0017] a first electrode;

[0018] a second electrode; and

[0019] an organic layer located between the first electrode and the second electrode; wherein,

[0020] The organic layer includes the above-mentioned o-phenanthroline derivative.

[0021] More preferably, the organic layer is a charge generation layer or an electron transport layer.

[0022] More preferably, the charge generation layer is an N-type charge generation layer.

[0023] More preferably, the N-type charge generation layer may be composed of metal or an n-type doped organic material.

[0024] More preferably, the metal is selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy or Yb.

[0025] The present invention further provides an organic electroluminescent device, comprising:

[0026] a first electrode;

[0027] a second electrode;

[0028] a first light-emitting portion of the first light-emitting layer, which is located between the first electrode and the second electrode;

[0029] a second light-emitting portion of the second light-emitting layer, which is located between the second electrode and the first light-emitting portion; and

[0030] a first charge generation layer located between the first light-emitting portion and the second light-emitting portion;

[0031] At least one of the first light-emitting portion, the second light-emitting portion, or the first charge generation layer contains the above-mentioned o-phenanthroline compound.

[0032] The present invention further provides a display or lighting device, which includes the above-mentioned organic electroluminescent device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 1 is a structural layer diagram of an organic electroluminescent device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] Another object of the present invention is to minimize the energy level difference between the n-type charge generation layer and the p-type charge generation layer to provide a phenanthroline derivative capable of increasing the amount of electron injection into the light-emitting portion and an organic light-emitting device containing the compound.

[0035] Another object of the present invention is to provide a phenanthroline derivative and an organic electroluminescent device comprising the same that can minimize the diffusion of alkali metal into a p-type charge generation layer even when the n-type charge generation layer is doped with an alkali metal.

[0036] According to the present invention, an organic electroluminescent device containing an o-phenanthroline derivative is provided, which minimizes the energy level difference between the n-type charge generation layer and the p-type charge generation layer, increases the electron injection amount of the light-emitting portion, thereby reducing the driving voltage and improving the efficiency.

[0037] According to the present invention, when the n-type charge generation layer is doped with an alkaline metal, the alkali metal is allowed to firmly penetrate into the main compound o-phenanthroline compound, thereby minimizing the diffusion of the alkali metal into the p-type charge generation layer, thereby making the device of the organic light emitting element.

[0038] In Formula 1, the o-phenanthroline derivative contains four nitrogen atoms, and aromatic compounds and heteroaryl groups are introduced into R1-R16 to make the nitrogen atoms more electron-rich, thereby promoting faster electron mobility and promoting electron transport. In addition, the N-type charge generation layer (N-CGL) contains nitrogen with sp2 hybrid orbitals, which is combined with the metal doped as the N-type charge generation layer to form a gap state. Therefore, electrons can be smoothly transferred from the P-type charge generation layer (P-CGL) to the N-type charge generation layer (N-CGL) through the gap state.

[0039] Furthermore, by introducing various substituents into the core structure, compounds having the inherent properties of the introduced substituents can be synthesized. For example, hole injection layer materials and hole transport layer materials used in organic electroluminescent devices can be compounds that transport holes along the highest energy orbital (HOMO) and compounds that block electrons from the light-emitting layer along the lowest energy orbital (LUMO).

[0040] In particular, the core structure of the compound has stable properties for electrons, which can improve the life of devices and can be used to prepare electron transport layers and hole blocking materials with appropriate energy band gaps.

[0041] Furthermore, by introducing various substituents into the core structure, the band gap can be fine-tuned while improving the interfacial properties between organic materials, thus diversifying the uses of the materials.

[0042] Among them, the charge generation layer (CG) includes a P-type charge generation layer (CGP) and an N-type charge generation layer (CGN), which are located between a first light-emitting portion including a first hole transport layer, a first light-emitting layer, and a first electron transport layer and a second light-emitting portion including a second hole transport layer, a second light-emitting layer, and a second electron transport layer in sequence, and is composed of a PN connection structure, connecting the above-mentioned first light-emitting portion and the second light-emitting portion.

[0043] That is, a PN junction structure is formed on the first electron transport layer, and a charge generation layer including a P-type charge generation layer (CGP) and an N-type charge generation layer (CGN) is provided. The N-type charge generation layer material can use a phenanthroline compound represented by Formula 1 according to the present invention. Here, the N-type charge generation layer provides electrons to the first electron transport layer of the first light-emitting portion, the first electron transport layer provides electrons to the first light-emitting layer, the P-type charge generation layer provides holes for the second hole transport layer of the second light-emitting portion, and the second hole transport layer provides holes for the second light-emitting portion.

[0044] Here, the first light-emitting layer of the first light-emitting portion and the second light-emitting layer of the second light-emitting portion may each include the same or different hosts and the same or different dopants. In addition, in the organic electroluminescent device according to an embodiment of the present invention, the hole injection layer (30) is located between the anode (20) and the first hole transport layer (40-1), and the second electron transport layer (60-2) is located between the electron injection layer (70) and the cathode (80).

[0045] Described organic electroluminescent device can have multiple variation.Some organic layers may be omitted or increased, may not be overlapping structures, may also be the overlapping of 2 or 4 above luminescent layers.In addition, organic electroluminescent device can comprise electron transport and electron injection and carry out organic layer simultaneously, also can use phenanthroline derivative of the present invention in this case.

[0046] Example

[0047] The preparation method of the organic electroluminescent device of the present invention is not particularly limited. Except for using the o-phenanthroline derivative shown in Formula 1, other preparation methods and materials for light-emitting devices known to those skilled in the art can be used to prepare the device.

[0048] Example 1: Synthesis of Compound 1

[0049] 1) Synthesis of intermediate 1-2

[0050]

[0051] Under nitrogen, a three-necked flask was charged with compound 1-1 (27.3 g, 81.3 mmol), pinacol diboron (24.8 g, 97.5 mmol), triphenylphosphine (6 mol%), bis(triphenylphosphine)palladium(II) dichloride (2.1 g, 3 mol%), potassium phenolate (16.1 g, 121.9 mmol), and anhydrous toluene (300 mL). After nitrogen replacement, the reaction was stirred at 50°C for 5 hours. The system was then cooled to room temperature and quenched with water. The reaction mixture was extracted with benzene and saturated brine. The organic phase was dried over anhydrous magnesium sulfate. The dried mixture was filtered and concentrated under reduced pressure. It could then be purified by column chromatography or distillation to afford intermediate 1-2 (15.5 g, 50% yield).

[0052] LC-MS: M / Z 382.18 (M+)

[0053] 2) Synthesis of Compound 1

[0054] After dissolving compound 1-2 (11.9 g, 31 mmol) in 1,4-dioxane (130 mL), 1-1 (10.7 g, 32 mmol), Pd(PPh3)4 (1.8 g, 1.5 mmol), and K2CO3 (12.8 grams, 93 mmol) were added thereto, and the resultant was stirred at 100°C for 6 hours. After the reaction was terminated, the resultant was cooled to room temperature and extracted with distilled water and ethyl acetate. The organic layer was dried over MgSO4, then filtered and concentrated. The concentrated residue was purified by column chromatography using ethyl acetate and hexane as developing solvents to obtain the target compound 1 (9.0 g, yield 57%). LC-MS: M / Z 510.18 (M+).

[0055] Example 2: Synthesis of Compound 5

[0056]

[0057] 1) Synthesis of Intermediate 5-1

[0058] Compound 1-1 (3.1 g, 9.3 mmol) and tributyl(1-ethoxy)stannane (3.3 g, 9.3 mmol) were dissolved in 1,4-dioxane (20 mL). Pd(PPh3)4 (0.56 g, 0.563 mmol) and PdCl2(dppf) (0.34 g, 0.46 mmol) were added and heated at 80°C for 5 h. The reaction mixture was cooled to room temperature, water was added, and the content was extracted with EtAc (2 x 20 ml). The organic layer was washed with brine, dried over sodium sulfate, and concentrated under reduced pressure to obtain intermediate 5-1 (0.83 g, 30% yield) by column chromatography. LC-MS: M / Z 298.11 (M+)

[0059] 2) Synthesis of Intermediate 5-3

[0060] Compound 5-1 (7.5 g, 25.0 mmol) and compound 5-2 (8.1 g, 32.0 mmol) were dissolved in ethanol, and potassium hydroxide (4.2 g, 76 mmol) was added. After stirring at room temperature for 3 hours, the precipitated solid was washed with methanol to obtain the target compound 5-3 (5.1 g, yield 35%). LC-MS: M / Z 512.06 (M+).

[0061] 3) Synthesis of compound 5

[0062] After dissolving compound 5-3 (12.3 g, 31 mmol) in 1,4-dioxane (130 mL), phenylboronic acid (8.6 g, 37 mmol), Pd(PPh3)4 (1.8 g, 1.5 mmol), and K2CO3 (12.8 g, 93 mmol) were added, and the mixture was stirred at 100°C for 6 hours. After the reaction was terminated, the mixture was cooled to room temperature and extracted with distilled water and ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated. The concentrated residue was purified by column chromatography using ethyl acetate and hexane as developing solvents to obtain the target compound 5 (11.9 g, 75% yield). LC-MS: M / Z 510.18 (M+).

[0063] Example 3: Synthesis of Compound 8

[0064]

[0065]

[0066] 1) Synthesis of intermediate 8-2

[0067] Compound 8-2 was synthesized by referring to the synthesis method of compound 5-1 to obtain compound 8-2 (0.70 g, yield 25%). LC-MS: M / Z 298.10 (M+)

[0068] 2) Synthesis of Intermediate 8-3

[0069] Compound 8-2 (7.5 g, 25.0 mmol) and compound 5-2 (8.1 g, 32.0 mmol) were dissolved in ethanol, and potassium hydroxide (4.2 g, 76 mmol) was added. After stirring at room temperature for 3 hours, the precipitated solid was washed with methanol to obtain the target compound 8-3 (3.6 g, yield 28%). LC-MS: M / Z 512.05 (M+).

[0070] 3) Synthesis of Compound 8

[0071] After dissolving compound 8-3 (12.3 g, 31 mmol) in 1,4-dioxane (130 mL), phenylboronic acid (8.6 g, 37 mmol), Pd(PPh3)4 (1.8 g, 1.5 mmol), and K2CO3 (12.8 grams, 93 mmol) were added, and the mixture was stirred at 100°C for 6 hours. After the reaction was terminated, the mixture was cooled to room temperature and extracted with distilled water and ethyl acetate. The organic layer was dried over MgSO4, filtered, and concentrated. The concentrated residue was purified by column chromatography using ethyl acetate and hexane as developing solvents to obtain the target compound 8 (10.6 g, yield 67%). LC-MS: M / Z 510.17 (M+).

[0072] Example 4: Synthesis of Compound 9

[0073]

[0074] To compound 9-1 (8.1 g, 25 mmol) and 5-1 (14.9 g, 50 mmol) was added p-toluenesulfonic acid monohydrate (23.8 g, 253.65 mmol), and the resulting mixture was stirred at 110°C for 8 hours. After the reaction was completed, the resulting mixture was cooled to room temperature and neutralized with an aqueous potassium carbonate solution. Extraction was then performed with dichloromethane. The organic layer was dried over MgSO4, filtered, and concentrated. The concentrated residue was purified by column chromatography using ethyl acetate and hexane as developing solvents to obtain the target compound 9 (4.1 g, 28.0%). LC-MS: M / Z 586.22 (M+).

[0075] Example 5: Synthesis of Compound 11

[0076]

[0077] Compound 11 was synthesized by referring to the method of Example 4. The other steps were all based on the synthesis of compound 9 to obtain compound 11 (3.5 g, yield: 24.0%). LC-MS: M / Z 586.21 (M + ).

[0078] Example 6: Synthesis of Compound 24

[0079]

[0080] Compound 24 was synthesized by referring to the method of Example 4. The other steps were all referred to the synthesis of compound 9 to obtain compound 24 (3.7 g, yield: 25.0%). LC-MS: M / Z 589.20 (M + ).

[0081] Example 7: Synthesis of Compound 29

[0082]

[0083] Compound 29 was synthesized by referring to the method of Example 1. Other steps were referred to the synthesis of compound 1 to obtain compound 29 (6.4 g, yield: 40.0%). LC-MS: M / Z 512.17 (M + ).

[0084] Device implementation

[0085] like Figure 1 As shown, the organic electroluminescent device according to an embodiment of the present invention includes an anode (20), a first hole transport layer (40-1), a first light-emitting layer (50-1) including a host and a dopant, a first light-emitting unit including a first electron transport layer (60-1), a charge generation layer (CG) including a P-type charge generation layer (CGP) and an N-type charge generation layer (CGN), and a second hole transport layer (40-2), a second light-emitting layer (50-2) including a host and a dopant, a second light-emitting unit including a second electron transport layer (60-3) and a cathode (80).

[0086] The layers of the organic electroluminescent device of the present invention can be formed by vacuum evaporation, sputtering, ion plating and the like, or wet film forming methods such as spin coating, printing and the like, and the solvent used is not particularly limited.

[0087] <Experimental Example 1> Manufacturing an Organic Light-Emitting Device

[0088] 1. First Implementation Method

[0089] Manufacturing of organic electroluminescent devices:

[0090] The ITO glass substrate was patterned to have a light emitting area of 3 mm×3 mm. The patterned ITO glass substrate was then washed and placed in a vacuum chamber with a standard pressure set to 1×10 -6 Afterwards, HATCN was evaporated on the ITO substrate to form a layer with a thickness of A first hole injection layer (HIL) is formed by evaporating HTL-1 on the first hole injection layer to a thickness of A hole transport layer (HTL) was formed by evaporating CBP+RD-1 (3 wt%) on the hole transport layer to form a layer with a thickness of The light-emitting layer (EML) was sequentially coated with ET-1 (thickness ), Yb (2 wt%) doped in compound 1 represented by formula 1 was evaporated The thickness of the N-type charge generation layer and HATCN is Then, HTL-1 was evaporated to form a P-type charge generation layer with a thickness of The second hole transport layer (HTL) is formed by evaporating BH+BD (3 wt%) to a thickness of The second light-emitting layer (EML) was deposited with ET-1 (thickness ) of the second electron transport layer, evaporated Liq (thickness of ), thereby manufacturing an organic electroluminescent device.

[0091]

[0092] 2. Second Implementation Plan

[0093] The organic electroluminescent device of the second embodiment is prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device is replaced by Compound 5 from Compound 1 of the first embodiment.

[0094] 3. Third Implementation Plan

[0095] The organic electroluminescent device of the third embodiment was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound 8 from Compound 1 of the first embodiment.

[0096] 4. Fourth Implementation Plan

[0097] The organic electroluminescent device of the fourth embodiment is prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device is replaced by Compound 9 from Compound 1 of the first embodiment.

[0098] 5. Fifth Implementation Plan

[0099] The organic electroluminescent device of the fifth embodiment is prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device is replaced by Compound 11 from Compound 1 of the first embodiment.

[0100] 6. Sixth Implementation Plan

[0101] The organic electroluminescent device of the sixth embodiment is prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device is replaced by Compound 24 from Compound 1 of the first embodiment.

[0102] 7. Seventh Implementation Plan

[0103] The organic electroluminescent device of the seventh embodiment is prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device is replaced by Compound 29 from Compound 1 of the first embodiment.

[0104] 8. Comparative Example 1

[0105] The organic electroluminescent device of Comparative Example 1 was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound Ref-2 from Compound 1 of the first embodiment.

[0106] 9. Comparative Example 2

[0107] The organic electroluminescent device of Comparative Example 1 was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound Ref-2 from Compound 1 of the first embodiment.

[0108] 10. Comparative Example 3

[0109] The organic electroluminescent device of Comparative Example 1 was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound Ref-3 from Compound 1 of the first embodiment.

[0110] 11. Comparative Example 4

[0111] The organic electroluminescent device of Comparative Example 1 was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound Ref-4 from Compound 1 of the first embodiment.

[0112] 12. Comparative Example 5

[0113] The organic electroluminescent device of Comparative Example 1 was prepared by the same method as the first embodiment, except that the N-type charge generation layer (N-CGL) of the organic electroluminescent device was replaced by Compound Ref-5 from Compound 1 of the first embodiment.

[0114] The organic electroluminescent device was prepared using a standard method known in the art at 10 mA / cm 2 The voltage and efficiency are tested under current conditions.

[0115] Table 1 shows the performance test results of the organic electroluminescent devices prepared in the examples of the present invention and the comparative examples.

[0116] Table 1

[0117]

[0118] As shown in Table 1, the organic electroluminescent device including the specific compound according to the present disclosure as a host material has higher luminous efficiency than the organic electroluminescent device of the comparative substance.

[0119] <Experimental Example 2> Manufacturing an Organic Light-Emitting Device

[0120] 13. Eighth Implementation Plan

[0121] Manufacturing of organic electroluminescent devices:

[0122] The ITO glass substrate was patterned to have a light emitting area of 3 mm×3 mm. The patterned ITO glass substrate was then washed and placed in a vacuum chamber with a standard pressure set to 1×10 -6 Afterwards, HATCN was evaporated on the ITO substrate to form a layer with a thickness of A hole injection layer (HIL) is formed by evaporating HTL-1 on the hole injection layer to a thickness of A hole transport layer (HTL) is formed on the hole transport layer with a thickness of CBP+RD-1 (3 wt%). The light-emitting layer (EML) is sequentially evaporated with compound 24 to a thickness of The electron transport layer and the evaporation thickness are of Liq, thereby manufacturing an organic electroluminescent device.

[0123] 14. Ninth Implementation Plan

[0124] The organic electroluminescent device of the eighth embodiment is prepared by the same method as the first embodiment, except that the electron transport layer is replaced by compound 29 instead of compound 24 of the eighth embodiment.

[0125] 15. Comparative Example 6

[0126] The organic electroluminescent device of the eighth embodiment was prepared by the same method as the first embodiment, except that the electron transport layer was replaced by Ref-4 from the compound 24 of the eighth embodiment.

[0127] 16. Comparative Example 7

[0128] The organic electroluminescent device of the eighth embodiment was prepared by the same method as the first embodiment, except that the electron transport layer was replaced by Ref-5 from the compound 24 of the eighth embodiment.

[0129] Table 2 shows the performance test results of the organic electroluminescent devices prepared in the examples of the present invention and the comparative examples.

[0130] Table 2

[0131]

[0132] As shown in Table 2, the organic electroluminescent device including the specific compound combination according to the present disclosure as a host material has higher luminous efficiency and lower driving voltage than the organic electroluminescent device of the comparative substance.

[0133] The above describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A phenanthroline derivative, wherein the phenanthroline derivative is any one of the following:

2. An organic electroluminescent device comprising: a first electrode; a second electrode; and an organic layer located between the first electrode and the second electrode; wherein, The organic layer is a charge generation layer or an electron transport layer; the charge generation layer or the electron transport layer comprises the o-phenanthroline derivative according to claim 1. The organic electroluminescent device according to claim 2 , wherein the charge generation layer is an N-type charge generation layer.

4. The organic electroluminescent device according to claim 3, wherein the N-type charge generation layer can be composed of a metal or an organic material doped with an n-type; the metal is selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Sm, Eu, Tb, Dy or Yb.

5. An organic electroluminescent device comprising: a first electrode; a second electrode; a first light-emitting portion of the first light-emitting layer, which is located between the first electrode and the second electrode; a second light-emitting portion of the second light-emitting layer, which is located between the second electrode and the first light-emitting portion; and a first charge generation layer located between the first light-emitting portion and the second light-emitting portion; At least one of the first light-emitting portion, the second light-emitting portion, or the first charge generation layer includes the o-phenanthroline compound according to claim 1 .

6. A display or lighting device comprising the organic electroluminescent device according to claim 2 or 5.

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