CN111138393B - Arylamine compound and organic electroluminescent device using the same - Google Patents

Abstract

The invention provides an arylamine compound and an organic electroluminescent device thereof, wherein the arylamine compound is represented by the following formula (I):

wherein X is O, S, or C (R) ¹ )(R ² )；R ¹ And R ² Each independently is a hydrogen atom, an alkyl or aryl group, or R ¹ And R ² A ring formed together; n1, n2 and n3 are integers; l is ¹ 、L ² And L ³ Each independently an arylene or heteroarylene group; a is aryl, heteroaryl, or-N (Ar) ³ )(Ar ⁴ ) A group; and Ar ¹ To Ar ⁴ Each independently is an aryl or heteroaryl group.

Description

Aromatic amine compound and organic electroluminescent device thereof

Technical Field

The present invention relates to an aromatic amine compound and an organic electroluminescent device using the same, in particular to an aromatic amine compound used as a material for a hole transport layer or a capping layer and an organic electroluminescent device using the same.

Background Art

With the advancement of technology, organic light emitting devices (OLEDs) have attracted much attention due to their advantages such as high response rate, light weight, thinness, wide viewing angle, bright colors, high contrast, no need for backlight, and low energy consumption. However, OLEDs still have problems of low efficiency and short lifespan.

In order to improve the efficiency and stability of OLED, generally, multiple organic thin films are connected in series between the cathode and anode of OLED. For example, OLED may be provided with a substrate, an anode, a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EL), an electron transport layer (ETL), an electron injection layer (EIL) and a cathode in sequence. When a voltage is applied to the anode and the cathode, the holes conducted by the anode are transferred to the emission layer through the hole injection layer and the hole transport layer, and the electrons emitted by the cathode are transferred to the emission layer through the electron injection layer and the electron transport layer, so that the holes and electrons are recombined in the emission layer to form electron-hole pairs, i.e., excitons. When the excitons decay from the excited state to the ground state, light is emitted.

The hole transport layer is formed by vacuum deposition, so the stability of the hole transport layer is insufficient. The hole transport layer may be partially crystallized due to the heat generated when the device is driven, and the hole transport material may also deteriorate, reducing the current efficiency and luminous efficiency of OLED. In order to improve the performance of OLED, some novel compounds have been developed as hole transport materials.

For example, US Patent Publication No. 2007/0262703 proposes using 2,2'-disubstituted 9,9'-spirobifluorenyl triaryl diamine as a hole transport material for the hole transport layer. However, even with the use of the aforementioned hole transport material, the current efficiency and luminous efficiency of OLEDs still need to be improved.

In addition, as International Invention Patent Publication No. 2017196081 proposes a condensed heterocyclic compound having an amine group connecting two benzene rings as a hole transport material for the hole transport layer. However, even if the aforementioned hole transport material is used, the service life of the OLED still cannot meet the requirements. Therefore, the present invention provides a novel aromatic amine compound to overcome the problems existing in the prior art.

Summary of the invention

The object of the present invention is to provide a novel aromatic amine compound which can be used in an organic electroluminescent device.

The invention further provides an organic electroluminescent device using the aromatic amine compound, which has a lower driving voltage.

The invention further provides an organic electroluminescent device using the aromatic amine compound, which has good luminous efficiency.

The invention further provides an organic electroluminescent device using the aromatic amine compound, thereby increasing the service life of the organic electroluminescent device.

To achieve the above-mentioned purpose, the aromatic amine compound of the present invention can be represented by the following formula (I):

In formula (I), X is O, S, or C(R ¹ )(R ² ); R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 6 to 30 carbon atoms in the ring, or R ¹ and R ² together form a ring having 6 to 15 carbon atoms in the ring;

n1, n2 and n3 are each independently an integer from 0 to 2, and n1, n2 and n3 are the same or different from each other;

L ¹ , L ² and L ³ are each independently an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 3 to 30 carbon atoms, and L ¹ , L ² and L ³ are the same as or different from each other;

A is an aromatic group having 6 to 30 ring carbon atoms, a heteroaryl group having 3 to 30 ring carbon atoms, or a -N(Ar ³ )(Ar ⁴ ) group; and

Ar ¹ to Ar ⁴ are each independently an aromatic group having 6 to 30 carbon atoms or a heteroaryl group having 3 to 30 carbon atoms, and Ar ¹ , Ar ² , Ar ³ and Ar ⁴ may be the same or different from each other.

Preferably, in formula (I), X is O, S, or C(CH ₃ ) ₂ .

When n1 is an integer of 2, two connected L ^1s are each independently an aryl group having 6 to 30 carbon atoms or a heteroaryl group having 3 to 30 carbon atoms, and the two L ^1s may be the same as or different from each other; for example, one L ¹ is an aryl group having 6 to 30 carbon atoms, and the other L ¹ is a heteroaryl group having 3 to 30 carbon atoms; similarly, two connected L ^2s may be the same as or different from each other, and two connected L ^3s may be the same as or different from each other.

Specifically, when n1, n2 or n3 is 1 or 2, the arylene group having 6 to 30 ring carbon atoms represented by L ¹ , L ² and L ³ may be any of the following:

wherein _m1 is an integer from 1 to 4, _m2 is an integer from 1 to 2, and _m3 is an integer from 1 to 3; and

^R3 to ^R6 are each independently selected from the group consisting of a hydrogen atom, a cyano group, a nitro group, a silane group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms;

When m ₁ , m ₂ or m ₃ is an integer greater than 1, each R ³ may be the same as or different from each other, each R ⁴ may be the same as or different from each other, each R ⁵ may be the same as or different from each other, and each R ⁶ may be the same as or different from each other.

Specifically, when n1, n2 or n3 is 1 or 2, the heteroaryl group having 3 to 30 ring carbon atoms represented by L ¹ , L ² and L ³ may be any of the following:

wherein _m1 is an integer from 1 to 4, _m3 is an integer from 1 to 3; and

^R3 and ^R4 are each independently selected from the group consisting of a hydrogen atom, a cyano group, a nitro group, a silane group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms;

When _m1 or _m3 is an integer greater than 1, each ^R3 may be the same as or different from each other, and each ^R4 may be the same as or different from each other.

Preferably, in formula (I), n1 and n2 are each independently 0 or 1.

Specifically, the aromatic group having 6 to 30 ring carbon atoms represented by any one of A, Ar ¹ to Ar ⁴ is selected from the group consisting of phenyl, biphenyl, terphenyl, naphthyl, fluorenyl), 9,9-dimethylfluorenyl, 9,9'-spirobifluorenyl, naphthylphenyl and isomers thereof.

Specifically, the heteroaryl group having 3 to 30 ring carbon atoms represented by any one of A, Ar ¹ to Ar ⁴ is selected from the group consisting of furyl, pyrrolyl, thienyl, imidazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, benzofuranyl, isobenzofuran, dibenzofuran, benzothienyl, isobenzothiophene, dibenzothiophene, quinolyl, isoquinoline, benzimidazole, carbazole, dicarbazolyl, and acridinyl.

Preferably, the aromatic group having 6 to 30 ring carbon atoms represented by any one of A, Ar ¹ to Ar ⁴ is selected from the group consisting of:

wherein _m1 is an integer from 1 to 4, _m3 is an integer from 1 to 3, and _m4 is an integer from 1 to 5; and

^R3 to ^R6 are each independently selected from the group consisting of a hydrogen atom, a cyano group, a nitro group, a silane group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms;

When m ₁ , m ₃ or m ₄ is an integer greater than 1, each R ³ may be the same as or different from each other, each R ⁴ may be the same as or different from each other, each R ⁵ may be the same as or different from each other, and each R ⁶ may be the same as or different from each other.

Preferably, the heteroaryl group having 3 to 30 ring carbon atoms represented by any one of A, Ar ¹ to Ar ⁴ is selected from the group consisting of:

wherein _m1 is an integer from 1 to 4, _m3 is an integer from 1 to 3; and

^R3 and ^R4 are each independently selected from the group consisting of a hydrogen atom, a cyano group, a nitro group, a silane group, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms;

When _m1 or _m3 is an integer greater than 1, each ^R3 may be the same as or different from each other, and each ^R4 may be the same as or different from each other.

In some embodiments of the present invention, n1 and n2 are the same integer, ^L1 and ^L2 are the same, and ^Ar1 and ^Ar2 are also the same. For example, n1 and n2 are both 1, and ^L1 and ^L2 are both phenylene, biphenylene, or 9,9-dimethylfluorene, but are not limited thereto.

*为与L³相接的位置)与A在L³上的位置不呈间位关系。举例而言，当L³为伸苯基时，该-N(Ar³)(Ar⁴)基团与该胺基多环部分可呈对位关系，其结构为

当L³为伸萘基时，该-N(Ar³)(Ar⁴)基团与该胺基多环部分不呈间位关系，其结构可为

但不限于此。In some embodiments of the present invention, when n3 is an integer of 1, ^L3 is an aryl group having 6 to 30 carbon atoms in the ring, and A is a -N( ^Ar3 )( ^Ar4 ) group, the amino polycyclic moiety (ie

* is the position connected to L ³ ) and the position of A on L ³ are not in a meta position. For example, when L ³ is a phenylene group, the -N(Ar ³ )(Ar ⁴ ) group and the amino polycyclic moiety may be in a para position, and the structure is

When L ³ is naphthylene, the -N(Ar ³ )(Ar ⁴ ) group is not in a meta position with the amino polycyclic moiety, and the structure may be

But it is not limited to this.

In the specification, X is C(R ¹ )(R ² ) which refers to “R ¹ and R ² together form a ring having 6 to 15 carbon atoms”, which may be an unsubstituted ring having 6 to 15 carbon atoms, or a ring having 6 to 15 carbon atoms substituted with at least one substituent; the substituent on the ring may be any one of R ³ to R ⁶ mentioned above.

In the specification, the "arylene group having 6 to 30 ring carbon atoms" referred to by L ¹ , L ² or L ³ may be an unsubstituted arylene group having 6 to 30 ring carbon atoms, or an arylene group having 6 to 30 ring carbon atoms and substituted with at least one substituent; the substituent on the arylene group may be any one of R ³ to R ⁶ mentioned above; similarly, the "heteroaryl group having 3 to 30 ring carbon atoms" referred to by L ¹ , L ² or L ³ may be an unsubstituted heteroaryl group having 3 to 30 ring carbon atoms, or a heteroaryl group having 3 to 30 ring carbon atoms and substituted with at least one substituent; the substituent on the heteroaryl group may be any one of R ³ to R ⁶ mentioned above.

In the specification, the "aromatic group" may be an unsubstituted aromatic group or an aromatic group substituted with at least one substituent; the "heteroaryl group" may be an unsubstituted heteroaryl group or a heteroaryl group substituted with at least one substituent. The substituent on the aromatic group may be any one of R ³ to R ⁶ mentioned above; the substituent on the heteroaryl group may be any one of R ³ to R ⁶ mentioned above.

In the specification, the "alkyl" may be an unsubstituted alkyl or an alkyl substituted with at least one substituent; the substituent on the alkyl may be but is not limited to a deuterium atom; the alkyl may be a linear or branched structure.

For example, the aromatic amine compound can be selected from the group consisting of:

The present invention further provides an organic electroluminescent device, which includes an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein the organic layer includes the aforementioned aromatic amine compound.

Specifically, the organic electroluminescent device includes a hole-assisting layer formed on the anode, a light-emitting layer formed on the hole-assisting layer, an electron-transporting layer formed on the light-emitting layer, and an electron-injection layer located between the electron-transporting layer and the cathode; the hole-assisting layer includes the organic layer.

In some embodiments, the hole-assisting layer may be a single-layer structure or a multi-layer structure disposed between the anode and the light-emitting layer; for example, when the hole-assisting layer is a multi-layer structure, the hole-assisting layer includes a hole-injection layer and a hole-transport layer; wherein the hole-injection layer is formed on the anode, and the hole-transport layer is formed between the hole-injection layer and the light-emitting layer; and the aromatic amine compound of the present invention described above serves as a hole-transporting material in the hole-transporting layer.

In some embodiments, the hole injection layer can be a single-layer structure or a multi-layer structure disposed between the anode and the hole transport layer; when the hole injection layer is a multi-layer structure, for example, the hole injection layer includes a first hole injection layer and a second hole injection layer.

Specifically, the hole injection layer may include HTM, p-type dopants, etc., but is not limited thereto.

In some embodiments, the hole transport layer can be a single-layer structure or a multi-layer structure disposed between a double-layer hole injection layer and a light-emitting layer; when the hole transport layer is a multi-layer structure, for example, the hole transport layer includes a first hole transport layer and a second hole transport layer, the hole transport material in the first hole transport layer may include an aromatic amine compound of the present invention or an existing hole transport material, and the hole transport material in the second hole transport layer may include another different aromatic amine compound of the present invention.

Preferably, the light-emitting layer is made of guest light-emitting material and host light-emitting material. The host material can be BH, EPH, etc., but is not limited thereto.

For an organic electroluminescent device that emits blue light, the guest luminescent material in the light-emitting layer may be BD, etc., but is not limited thereto.

For an organic electroluminescent device emitting green light, the guest luminescent material in the emitting layer may be GD, etc., but is not limited thereto.

For an organic electroluminescent device that emits red light, the guest luminescent material in the light-emitting layer may be RD, etc., but is not limited thereto.

Preferably, the electron transport layer may include ET, 8-hydroxyquinoline lithium, or the like, but is not limited thereto.

Preferably, the electron injection layer may include lithium fluoride (LiF) or the like, but is not limited thereto.

Preferably, the anode may be an indium tin oxide electrode, but is not limited thereto.

Preferably, the cathode may be an aluminum electrode.

The present invention further provides an organic electroluminescent device, which includes an anode, a cathode and a covering layer disposed on the cathode. The cathode is disposed between the anode and the covering layer, and the covering layer includes the aforementioned aromatic amine compound.

Since the aforementioned aromatic amine compound has a high refractive index, when it is used as a material for the cover layer, it can increase the reflection of the frame surface between the cover layer and the outside world. By increasing the reflection, the cover layer can collect light to enhance the brightness of the top-emitting organic electroluminescent device, or produce a micro-resonant cavity effect at a specific wavelength.

Other purposes, effects and technical features of the present invention will be described in more detail with reference to drawings, embodiments and comparative examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of an organic electroluminescent device.

FIG. 2 and FIG. 3 are hydrogen nuclear magnetic resonance spectra (H ¹ -NMR) of compound 3. FIG.

FIG4 and FIG5 are H ¹ -NMR of Compound 5. FIG5 is a graph showing the ...

FIG6 and FIG7 are H 1 -NMR of compound 6. FIG6 and FIG7 are H ¹ -NMR of compound 6.

FIG8 and FIG9 are H ¹ -NMR of compound 9. FIG9 is a graph showing the ...

10 and 11 are H ¹ -NMR of compound 13.

12 and 13 are H ¹ -NMR of Compound 18.

DETAILED DESCRIPTION

Several embodiments are listed below to illustrate the embodiments of the compounds of the present invention and the organic electronic devices thereof, so as to highlight the differences of the present invention compared to the prior art. A person skilled in the art can easily understand the advantages and effects that can be achieved by the present invention through the contents of this specification, and can make various modifications and changes without departing from the spirit of the present invention to implement or apply the contents of the present invention.

Synthesis of Intermediate An

The intermediate An is used to prepare an aromatic amine compound, and the intermediate An can be synthesized by the following steps.

Synthesis Mechanism A1

wherein X is O, S, or C(R ¹ )(R ² ); R ¹ and R ² are each independently a hydrogen atom, a deuterium atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 6 to 30 carbon atoms on the ring, or R ¹ and R ² together form a ring having 6 to 15 carbon atoms on the ring; n1 and n2 are each independently an integer from 0 to 2, and n1 and n2 are the same as or different from each other; L ¹ and L ² are each independently an aryl group having 6 to 30 carbon atoms on the ring or a heteroaryl group having 3 to 30 carbon atoms on the ring, and L ¹ and L ² are the same as or different from each other; and Ar ¹ and Ar ² are each independently an aromatic group having 6 to 30 carbon atoms on the ring or a heteroaryl group having 3 to 30 carbon atoms on the ring.

Synthesis of intermediate A1

Intermediate A1 can be synthesized by the following synthesis mechanism A1-1.

Synthesis Mechanism A1-1

Step 1: Synthesis of intermediate A1-1

4-Bromodibenzofuran (10 g, 40.47 mmole), di(4-biphenyl)amine (12.36 g, 38.45 mmole) and sodium tert-butoxide (11.67 g, 121.41 mmole) were placed in a 500 mL reaction bottle, and 100 mL of toluene was added. Then, tri(dibenzylideneacetone)dipalladium (Pd(dba) ₂ ) (1.16 g, 2.02 mmole) and 20 mL of toluene were added to a 50 mL scintillation vial, and then tri-tert-butylphosphine (P(t-Bu) ₃ ) (0.98 g, 4.86 mmole) was added to form a first mixed solution, and the scintillation vial was heated to change the color of the first mixed solution from dark red to dark green; finally, the first mixed solution was slowly added to the reaction bottle, and the temperature was raised to 110° C. to continue the reaction for 18 hours to form a second mixed solution. After the reaction was completed as confirmed by TLC, the second mixed solution was cooled to room temperature, 300 mL of deionized water was added, and the mixture was stirred for 30 minutes and then allowed to stand to separate layers. Extraction was performed with 200 mL of ethyl acetate each time, and the extraction was repeated three times. The organic layers collected from the three extractions were then added with magnesium sulfate (MgSO ₄ ) to remove water, filtered and separated, and concentrated to dryness to obtain a crude product. The crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 14.8 g of a product (i.e., intermediate A1-1), and the yield of the product was 75%.

Step 2: Synthesis of Intermediate A1

In a 500 mL reaction bottle, intermediate A1-1 (10 g, 20.51 mmole) was mixed with 200 mL of dichloromethane to form a third mixed solution, which was moved to a 0°C ice bath, and a feeding funnel was added to the reaction bottle. N-bromosuccinimide (4.02 g, 22.56 mmole) was then dissolved in 40 mL of acetonitrile and added dropwise to the reaction bottle from the feeding funnel at a rate of 2 drops/second, and the reaction was continued at 0°C for 1 hour. After the completion of the reaction was confirmed by TLC, 200 mL of saturated sodium bicarbonate aqueous solution was added and stirred for 30 minutes, and then allowed to stand to separate layers. 200 mL of dichloromethane was used each time, and the extraction was repeated three times. Magnesium sulfate (MgSO ₄ ) was added to the organic layer collected from the three extractions to remove water, and the organic layer was filtered and separated and concentrated to dryness to obtain a crude product. The crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 20:1) to obtain 9.3 g of a product (i.e., intermediate A1), and the yield of the product was 80%.

Synthesis of intermediate A2

Intermediate A2 can be synthesized by a synthetic mechanism A1-1 similar to that of intermediate A1, the main difference being the reactant An. Intermediate A2 can be synthesized by the following synthetic mechanism A1-2.

Synthesis Mechanism A1-2

In step 1, the difference is that 15.44 g (38.45 mmole) of bis(9,9-dimethylfluorene)amine is used to replace 12.36 g of di(4-biphenylyl)amine, and 17 g of intermediate A2-1 is obtained. The yield of intermediate A2-1 is 74%.

Step 2: Synthesis of intermediate A2

In a 500 mL reaction bottle, intermediate A2-1 (10 g, 17.61 mmole) was mixed with 176 mL of dichloromethane to form a mixed solution, which was then transferred to an ice bath at 0°C, and a feeding funnel was added to the reaction bottle. NBS (3.45 g, 19.38 mmole) was then dissolved in 35 mL of acetonitrile and added dropwise from the feeding funnel to the reaction bottle at a rate of 2 drops/second, and the reaction was continued at 0°C for 1 hour. After the completion of the reaction was confirmed by TLC, 176 mL of saturated sodium bicarbonate aqueous solution was added and stirred for 30 minutes, and then allowed to stand to separate layers. 200 mL of dichloromethane was used for extraction each time, and the extraction was repeated three times. Magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 20:1) to obtain 8.7 g of a product (i.e., intermediate A2), and the yield of the product was 76%.

Synthesis of intermediate A3

Intermediate A3 can be synthesized by a synthetic mechanism A1-1 similar to that of intermediate A1, the main difference being the reactant Sn. Intermediate A3 can be synthesized by the following synthetic mechanism A1-3.

Synthesis Mechanism A1-3

Step 1: Synthesis of intermediate A3-1

4-Bromodibenzothiophene (10 g, 38.0 mmole), di(4-biphenyl)amine (11.6 g, 36.10 mmole) and sodium tert-butoxide (10.96 g, 114 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added. Then, Pd(dba) ₂ (1.09 g, 1.90 mmole) and 20 mL of toluene were added to a 50 mL scintillation bottle, and then P(t-Bu) ₃ (0.92 g, 4.56 mmole) was added to form a first mixed solution, and the scintillation bottle was heated to change the color of the first mixed solution from dark red to dark green; finally, the first mixed solution was slowly added to the reaction bottle, and the temperature was raised to 110° C. and the reaction was continued for 16 hours to form a second mixed solution. After the completion of the reaction was confirmed by TLC, the second mixed solution was cooled to room temperature, 300 mL of deionized water was added and stirred for 30 minutes, and then allowed to stand to separate layers, and extracted with 100 mL of toluene each time, and the extraction was repeated three times, and then magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 14.3 g of a product (i.e., intermediate A3-1), and the yield of the product was 75%.

Step 2: Synthesis of intermediate A3

In a 500 mL reaction bottle, intermediate A3-1 (10 g, 19.85 mmole) was mixed with 200 mL of dichloromethane to form a third mixed solution, which was transferred to a 0°C ice bath, and a feeding funnel was added to the reaction bottle. NBS (3.53 g, 19.85 mmole) was then dissolved in 40 mL of acetonitrile and added dropwise to the reaction bottle from the feeding funnel at a rate of 2 drops/second, and the reaction was continued at 0°C for 2 hours. After the completion of the reaction was confirmed by TLC, 300 mL of saturated sodium bicarbonate aqueous solution was added and stirred for 30 minutes, then allowed to stand to separate layers, extracted with 100 mL of dichloromethane each time, and the extraction was repeated three times. Magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 20:1) to obtain 10.4 g of a product (i.e., intermediate A3), and the yield of the product was 90%.

Synthesis of Aromatic Amines

The intermediate An can be used to synthesize an aromatic amine compound by synthesis method I or synthesis method II; in synthesis method I, the reactant An is an amine compound substituted with a diaromatic group and/or a heteroaromatic group, such as di(4-biphenyl)amine, bis(9,9-dimethylfluorene)amine, etc.; in synthesis method II, the reactant Bn is an aromatic compound having a boronic acid group or a boronic acid pinacol ester group, such as phenylboric acid, 3-boronic acid pinacol ester-N-biphenylcarbazole, etc.

Synthesis method I:

Synthesis method II:

Synthesis method I:

Synthesis of compound 1

In the synthesis method I, the intermediate A1 (10 g, 17.65 mmole), di(4-biphenyl)amine (5.2 g, 16.18 mmole) (i.e., reactant A1) and sodium tert-butoxide (4.66 g, 48.54 mmole) are placed in a 500 mL reaction bottle, and 100 mL of toluene is added. Then, Pd(dba) ₂ (0.47 g, 0.81 mmole) and 20 mL of toluene are added to a 50 mL scintillation bottle, and then P(t-Bu) ₃ (0.39 g, 1.94 mmole) is added to form a first mixed solution, and the scintillation bottle is heated to change the color of the first mixed solution from dark red to dark green; finally, the first mixed solution is slowly added to the reaction bottle, and the temperature is raised to 110° C. and the reaction is continued for 18 hours to form a second mixed solution. After the completion of the reaction was confirmed by TLC, the second mixed solution was cooled to room temperature, 300 mL of deionized water was added and stirred for 30 minutes, and then allowed to stand to separate layers, and extracted with 200 mL of ethyl acetate each time, and the extraction was repeated three times, and then magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 10 g of compound 1, and the yield of compound 1 was 76%.

Synthesis of compound 2

Compound 2 was synthesized using method I in the same manner as compound 1, with the main difference being that when compound 2 was synthesized, 6.5 g (16.19 mmole) of bis(9,9-dimethylfluorene)amine (i.e., reactant A2) was used to replace 5.2 g of di(4-biphenyl)amine (i.e., reactant A1) to obtain 11.5 g of compound 2, with a yield of 80%.

Synthesis method II:

Synthesis of compound 3

In synthesis method II, intermediate A1 (10 g, 17.65 mmole) and 3-(4-dibenzofuranyl)phenylboronic acid (5.59 g, 19.42 mmole) (i.e., reactant B1) are placed in a 500 mL reaction bottle, and 120 mL of toluene is added; potassium carbonate (K ₂ CO ₃ ) (6.10 g, 44.13 mmole) is dissolved in 65 mL of deionized water and added to the reaction bottle; then, tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ) (1.02 g, 0.88 mmole) and 22 mL of ethanol are added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution is heated to 76° C. and reacted for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 200 mL of ethyl acetate each time, and the extraction was repeated three times, and then magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 10.0 g of compound 3, and the yield of compound 3 was 78%. The chemical structure of compound 3 was identified by a 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG2 , and the signal with a chemical shift of 7 ppm to 8.4 ppm is particularly amplified as shown in FIG3 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 8.24 (s, 1H), 8.07 (t, 1H), 7.99 (d, 1H), 7.96 (d, 1H), 7.80 (d, 1H), 7.73 (d, 2H), 7.69 (d, 1H), 7.60 (d, 4H), 7.53 (d, 4H), 7.51 (d, 1H), 7.46 to 7.24 (m, 17H), 7.16 (t, 1H).

Synthesis of compound 4

Compound 4 was synthesized using method II in the same manner as compound 3, with the main difference being that 4.12 g (19.42 mmole) of 4-dibenzofuranboronic acid (i.e., reactant B2) was used to replace 5.59 g of reactant B1 to obtain 9.1 g of compound 4, with a yield of 79%.

Synthesis of compound 5

Compound 5 was synthesized using method II in the same manner as compound 3, with the main difference being that 4.82 g (19.42 mmole) of 4-(1-naphthyl)phenylboronic acid (i.e., reactant B3) was used to replace 5.59 g of reactant B1 to obtain 8.9 g of compound 5, with a yield of 73%. The chemical structure of compound 5 was identified by 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG4 , and the signal with chemical shift of 7 ppm to 8.3 ppm was amplified as shown in FIG5 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 8.09 (d, 1H), 7.96 (d, 1H), 7.92 (dd, 1H), 7.81 (d, 2H), 7.74 (d, 1H), 7.68 (d, 2H), 7.62-7.50 (m, 12H), 7.45 to 7.26 (m, 14H), 7.18 (t, 1H).

Synthesis of compound 6

Compound 6 was synthesized using method II in the same manner as compound 3, with the main difference being that 2.37 g (19.42 mmole) of phenylboronic acid (i.e., reactant B4) was used to replace 5.59 g of reactant B1 to obtain 7.5 g of compound 6, with a yield of 75%. The chemical structure of compound 6 was identified by 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG6 , and the signal with chemical shift of 6.9 ppm to 7.9 ppm is particularly amplified as shown in FIG7 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 7.66 (d, 2H), 7.59 (dd, 4H), 7.56 to 7.46 (m, 8H), 7.41 (t, 4H), 7.39 (d, 1H), 7.34 (dd, 2H), 7.30 (t, 2H), 7.26 to 7.21 (m, 5H), 7.10 (td, 1H).

Synthesis of compound 7

Compound 7 was synthesized using method II in the same manner as compound 3, with the main difference being that 3.34 g (19.42 mmole) of 1-naphthaleneboronic acid (i.e., reactant B5) was used to replace 5.59 g of reactant B1 to obtain 8.0 g of compound 7, with a yield of 75%.

Synthesis of compound 8

Compound 8 was synthesized using method II in the same manner as compound 3, with the main difference being that 3.34 g (19.42 mmole) of 2-naphthaleneboronic acid (i.e., reactant B6) was used to replace 5.59 g of reactant B1 to obtain 8.4 g of compound 8, with a yield of 78%.

Synthesis of compound 9

Compound 9 was synthesized in the same manner as compound 3 using method II; intermediate A1 (10 g, 17.65 mmole) and 3-boronic acid pinacol ester-N-biphenylcarbazole (i.e. reactant B7) (9.17 g, 20.60 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added; then K ₂ CO ₃ (5.93 g, 42.91 mmole) was dissolved in 70 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (0.99 g, 0.86 mmole) and 30 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and the reaction was continued for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 100 mL of ethyl acetate each time, and the extraction was repeated three times, and then magnesium sulfate was added to the organic layer collected from the three extractions to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 10.5 g of compound 9, and the yield of compound 9 was 79%. The chemical structure of compound 9 was identified by a 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG8 , and the signal with a chemical shift of 6.9 ppm to 8.6 ppm is particularly amplified as shown in FIG9 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 8.24 (s, 1H), 8.46 (s, 1H), 8.17 (d, 1H), 7.88 (d, 1H), 7.54 (dd, 4H), 7.53 (s, 1H), 7.65 (d, 1H), 7.60 (d, 4H), 7.56 to 7.26 (m, 25H), 7.06 (t, 1H).

Synthesis of compound 10

Compound 10 was synthesized using method II in the same manner as compound 3, with the main difference being that 6.99 g (19.42 mmole) of B-9,9'-spirobifluorene-2'-ylboronic acid (i.e., reactant B8) was used to replace 5.59 g of reactant B1 to obtain 10.5 g of compound 10, with a yield of 74%.

Synthesis of compound 11

Compound 11 was synthesized using method II in the same manner as compound 3, with the main difference being that 5.58 g (19.42 mmole) of N-phenyl-3-carbazole boronic acid (i.e., reactant B9) was used to replace 5.59 g of reactant B1 to obtain 10 g of compound 11, with a yield of 78%.

Synthesis of compound 12

Compound 12 was synthesized in the same manner as compound 3 using method II; intermediate A1 (10 g, 17.65 mmole) and 4-(2-naphthyl)phenylboronic acid (i.e. reactant B10) (4.82 g, 19.42 mmole) were placed in a 500 mL reaction bottle, and 150 mL of toluene was added; K ₂ CO ₃ (6.10 g, 44.13 mmole) was then dissolved in 65 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (1.53 g, 1.32 mmole) and 22 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and the reaction was continued for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 100 mL of toluene each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 8.56 g of compound 12, and the yield of compound 12 was 70%.

Synthesis of compound 13

Compound 13 was synthesized in the same manner as compound 3 using method II; intermediate A1 (10 g, 17.65 mmole) and 3-biphenylboronic acid (i.e. reactant B11) (4.19 g, 21.18 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added; K ₂ CO ₃ (6.09 g, 44.13 mmole) was then dissolved in 50 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (1.02 g, 0.88 mmole) and 20 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and the reaction was continued for 16 hours. After the completion of the reaction was confirmed by TLC, 100 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, and extracted with 100 mL of ethyl acetate each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 12 g of compound 13, and the yield of compound 13 was 67%. The chemical structure of compound 13 was identified by a 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG10 , and the signal with a chemical shift of 6.8 ppm to 8.4 ppm is particularly amplified as shown in FIG11 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 7.92 (s, 1H), 7.72 (d, 1H), 7.68 (d, 1H), 7.64 (d, 1H), 7.62 (d, 2H), 7.59 (d, 4H), 7.52 (d, 4H), 7.46 to 7.26 (m, 17H), 7.11 (t, 2H).

Synthesis of compound 14

In synthesis method II, intermediate A2 (10 g, 15.47 mmole) and reactant B1 (4.9 g, 17.01 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added; then K ₂ CO ₃ (5.34 g, 38.66 mmole) was dissolved in 65 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (0.89 g, 0.77 mmole) and 22 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and reacted for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 200 mL of ethyl acetate each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 9.0 g of compound 14, and the yield of compound 14 was 72%.

Synthesis of compound 15

In synthesis method II, intermediate A2 (10 g, 15.47 mmole) and reactant B4 (2.27 g, 18.56 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added; then K ₂ CO ₃ (5.34 g, 38.66 mmole) was dissolved in 70 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (0.89 g, 0.77 mmole) and 30 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and reacted for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, and extracted with 100 mL of ethyl acetate each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 20:1) to obtain 8.1 g of compound 15, and the yield of compound 15 was 82%.

Synthesis of compound 16

Compound 16 was synthesized using method II in the same manner as compound 15, with the main difference being that 3.68 g (18.56 mmole) of reactant B11 was used to replace 2.27 g of reactant B4 to obtain 9.46 g of compound 16, with a yield of 85%.

Synthesis of compound 17

Compound 17 was synthesized using method II in the same manner as compound 15, with the main difference being that 4.42 g (18.56 mmole) of 9,9-dimethyl-2-boronic acid fluorene (i.e., reactant B12) was used to replace 2.27 g of reactant B4 to obtain 10.34 g of compound 17, and the yield of compound 17 was 88%.

Synthesis of compound 18

In synthesis method II, intermediate A3 (10 g, 17.17 mmole) and reactant B4 (2.30 g, 18.88 mmole) were placed in a 500 mL reaction bottle, and 150 mL of toluene was added; then K ₂ CO ₃ (5.93 g, 42.91 mmole) was dissolved in 65 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (1.49 g, 1.29 mmole) and 22 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and reacted for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 100 mL of toluene each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 7.66 g of compound 18, and the yield of compound 18 was 77%. The chemical structure of compound 18 was identified by a 400 MHz nuclear magnetic resonance spectrometer. Its NMR spectrum is shown in FIG12 , and the signal with a chemical shift of 6.6 ppm to 7.9 ppm is particularly amplified as shown in FIG13 . Its characteristic peak signals are as follows: ¹ H-NMR (CDCl ₃ ): 7.68 (d, 1H), 7.58 (d, 4H), 7.54 to 7.49 (m, 9H), 7.43-7.36 (m, 5H), 7.29 (t, 2H), 7.28 (d, 2H), 7.21 (d, 4H), 7.17 (d, 1H), 7.05 (t, 1H).

Synthesis of compound 19

Compound 19 was synthesized using method II in the same manner as compound 18, with the main difference being that 3.74 g (18.88 mmole) of reactant B11 was used to replace 2.30 g of reactant B4 during the synthesis of compound 19 to obtain 8.44 g of compound 19, with a yield of 75%.

Synthesis of compound 20

Compound 20 was synthesized using method II in the same manner as compound 18, with the main difference being that 4.5 g (18.88 mmole) of reactant B12 was used to replace 2.30 g of reactant B4 to obtain 8.36 g of compound 20, with a yield of 70%.

Synthesis of compound 21

Compound 21 was synthesized using method II in the same manner as compound 3; intermediate A1 (10 g, 17.65 mmole) and reactant B12 (4.62 g, 19.42 mmole) were placed in a 500 mL reaction bottle, and 120 mL of toluene was added; K ₂ CO ₃ (6.10 g, 44.13 mmole) was then dissolved in 65 mL of deionized water and added to the reaction bottle; then, Pd(PPh ₃ ) ₄ (1.02 g, 0.88 mmole) and 22 mL of ethanol were added to the reaction bottle under a nitrogen system to form a mixed solution, and the mixed solution was heated to 76° C. and the reaction was continued for 16 hours. After the completion of the reaction was confirmed by TLC, 300 mL of deionized water was added and stirred for 30 minutes, then allowed to stand to separate the layers, extracted with 100 mL of ethyl acetate each time, and the extraction was repeated three times. The organic layer collected from the three extractions was added with magnesium sulfate to remove water, filtered and separated, and concentrated to dryness to obtain a crude product; the crude product was purified by column chromatography using an eluent mixed with n-hexane and ethyl acetate (volume ratio of 10:1) to obtain 9 g of compound 21, and the yield of compound 21 was 75%.

Physical Property Analysis of Aromatic Amine Compounds

1. Measurement of glass transition temperature (T _g ): The glass transition temperature of compounds 1 to 20 and NPB was measured using a differential scanning calorimeter (DSC) (instrument model: PerkinElmer, DSC8000) at a programmed heating rate of 20° C./min.

2. Measurement of thermal decomposition temperature (T _d ): The thermal decomposition properties of compounds 1 to 20 and NPB were measured using a thermogravimetric analyzer (Perkin Elmer, TGA8000) at normal pressure and a nitrogen atmosphere at a programmed heating rate of 20° C./min. The temperature at which the weight decreased to 95% of the initial weight was defined as the thermal decomposition temperature.

3. Measuring the energy level of the highest filled molecular orbital (HOMO) of the molecule: Compounds 1 to 20 and NPB were made into thin films, and their ionization potential values were measured using a photoelectron spectrophotometer (instrument model: Riken Keiki, Surface Analyzer) in the atmosphere. The values were further converted into HOMO energy level values.

4. Measure the energy level of the lowest unfilled molecular orbital (LUMO) of the molecule: The thin film of the above-mentioned compounds 1 to 20 and NPB was measured with a UV-visible spectrophotometer (instrument model: Perkin Elmer, Lambda 20) at the boundary value (onset) of their absorption wavelength, and the boundary value was converted into an energy gap value, and the energy gap value was subtracted from the numerical value of the HOMO energy level to obtain the LUMO energy level value.

5. Refractive index: The refractive index was measured using a full spectrum ellipsometer (instrument model: SE-RD). Spectroscopic ellipsometry (SE) uses infrared, visible or ultraviolet light in the spectral region to measure the complex refractive index. Films of compounds 1 to 20 and NPB with a thickness of 500 angstroms were fixedly measured and the refractive index of the films was observed at 555 nm.

Table 1 Measurement results of T _g , HOMO energy level and LUMO energy level of compounds 1 to 13, compounds 15 to 20 and NPB

Preparation of blue light organic electroluminescent device

Before the substrate 10 is loaded into the evaporation system for use, it is first cleaned with a solvent (acetone and isopropanol) and ultraviolet ozone to degrease the substrate, and then the cleaned substrate 10 is transferred to the evaporation equipment. Please refer to FIG1 , the heated evaporation boat deposits each layer on the substrate 10 in sequence under a vacuum of about 10 ^-6 torr. After each layer is formed in the evaporation equipment, the substrate 10 coated with each layer is transferred from the evaporation equipment to a drying oven, and then packaged with an ultraviolet curable epoxy resin and a glass cover plate containing a moisture absorbent (not shown) to obtain a blue light organic electroluminescent device (B-OLED). The B-OLED emits blue light and has a light-emitting area of 9 square millimeters. The order of each layer, the name of the layer and its symbol, the thickness, and the materials used in preparing the B-OLED are listed in Table 2; except for the chemical structural formula of the aromatic amine compound of the present invention, the chemical structural formulas of the remaining materials used are listed in Table 5.

Table 2 The order, layer names and symbols, thickness, and materials used in B-OLED

Preparation of green organic electroluminescent device

Before the substrate 10 is loaded into the evaporation system for use, it is first cleaned with a solvent (acetone and isopropyl alcohol) and ultraviolet ozone to degrease the substrate, and then the cleaned substrate 10 is transferred to the evaporation equipment. As shown in FIG1 , each layer is sequentially deposited on the substrate 10 by a heated evaporation boat at a vacuum of about 10 ^{- 6} torr. After each layer is formed in the evaporation equipment, the substrate 10 coated with each layer is transferred from the evaporation equipment to a drying oven, and then packaged with an ultraviolet curable epoxy resin and a glass cover plate containing a moisture absorbent (not shown) to obtain a green organic electroluminescent device (G-OLED). The G-OLED emits green light and has a light-emitting area of 9 square millimeters. The order of each layer, the name of the layer and its symbol, the thickness, and the materials used in preparing the G-OLED are listed in Table 3; except for the chemical structural formula of the aromatic amine compound of the present invention, the chemical structural formulas of the remaining materials used are listed in Table 5.

Table 3 The order, layer names and symbols, thickness, and materials used in G-OLED

Preparation of red light organic electroluminescent device

Before the substrate 10 is loaded into the evaporation system for use, it is first cleaned with a solvent (acetone and isopropyl alcohol) and ultraviolet ozone to degrease the substrate, and then the cleaned substrate 10 is transferred to the evaporation equipment. As shown in FIG1 , each layer is sequentially deposited on the substrate 10 by a heated evaporation boat at a vacuum of about 10 ^{- 6} torr. After each layer is formed in the evaporation equipment, the substrate 10 coated with each layer is transferred from the evaporation equipment to a drying oven, and then packaged with an ultraviolet curable epoxy resin and a glass cover plate containing a moisture absorbent (not shown) to obtain a red organic electroluminescent device (R-OLED). The R-OLED emits red light and has a light-emitting area of 9 square millimeters. The order of each layer, the name of the layer and its symbol, the thickness, and the materials used for preparing the R-OLED are listed in Table 4; except for the chemical structural formula of the aromatic amine compound of the present invention, the chemical structural formulas of the remaining materials used are listed in Table 5.

Table 4 The order, layer names and symbols, thickness, and materials used in R-OLED

Table 5: Chemical structures of materials used in organic electroluminescent devices

Performance of B-OLED/G-OLED/R-OLED devices

The performance of B-OLED/G-OLED/R-OLED was measured at room temperature using a constant current source (KEITHLEY 2400) and a photometer (PHOTO RESEARCH SpectraScan PR650). The efficiency of each embodiment and each comparative example was measured at a current density of 10 mA/cm ² : driving voltage, brightness (L, unit: candlelight/square meter), current efficiency (yield, unit: candlelight/ampere), luminous efficiency (efficiency, unit: lumen/watt), external quantum efficiency, and service life (LT95 value), and the measurement results of B-OLED/G-OLED/R-OLED are listed in Tables 6 to 8, respectively. Among them, the service life test of B-OLED is fixed at an initial brightness of 1000 nits, the service life test of G-OLED is fixed at an initial brightness of 10000 nits, and the service life test of R-OLED is fixed at an initial brightness of 6000 nits.

Performance test of B-OLED/G-OLED/R-OLED

1. Each of the organic electroluminescent devices prepared above was measured for its luminescence properties such as driving voltage, brightness, current efficiency and luminous efficiency at room temperature using a constant current source (instrument model: KEITHLEY2400 Source Meter, manufactured by Keithley Instruments, Inc., USA) and a photometer (instrument model: PHOTO RESEARCH SpectraScan PR 650, manufactured by PhotoResearch Corporation);

2. LT95 value test: measure the time it takes for the brightness level to drop from the initial brightness (1000cd/ ^m2 for B-OLED, 10000cd/ ^m2 for G-OLED, 6000cd/ ^m2 for R-OLED) to 95% of the initial brightness, as a measure of the service life or stability of OLED.

Table 6: Compound number used in B-OLED, driving voltage, luminance, current efficiency, luminous efficiency, external quantum efficiency, and LT95 value measurement results

Table 7: Compound number used in G-OLED, driving voltage, brightness, current efficiency, luminous efficiency, external quantum efficiency, and LT95 value measurement results

Table 8: Compound number used in R-OLED, driving voltage, brightness, current efficiency, luminous efficiency, external quantum efficiency, and LT95 value measurement results

The experimental results in Tables 6 to 8 above show that the aromatic amine compounds of the present invention can be used as hole-assisting materials for blue, green or red organic electroluminescent devices, and can help the OLEDs using the aromatic amine compounds to have lower driving voltage, better luminous efficiency, external quantum efficiency and longer service life. In particular, the OLEDs of Examples 1 to 11 and 13 to 17 also have better brightness and current efficiency.

The above embodiments are merely examples of the present invention and are not intended to limit the scope of the rights claimed by the present invention in any way. A person skilled in the art can make adjustments according to the spirit of the present invention, such as the number, position or arrangement of substituents. The scope of the rights claimed by the present invention shall be based on the claims, and shall not be limited to the above embodiments.

Claims (4)

1. An aromatic amine compound selected from the group consisting of:

2. An organic electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises the aromatic amine compound according to claim 1. 3. An organic electroluminescent device according to claim 2, wherein the organic electroluminescent device further comprises a hole assisting layer, a light-emitting layer, an electron transport layer and an electron injection layer; the hole assisting layer is formed on the anode; the light-emitting layer is formed on the hole assisting layer; the electron transport layer is formed on the light-emitting layer; the electron injection layer is formed between the electron transport layer and the cathode; the hole assisting layer includes the organic layer. 4. An organic electroluminescent device, comprising an anode, a cathode and a covering layer disposed on the cathode, wherein the cathode is disposed between the anode and the covering layer, and the covering layer comprises the aromatic amine compound according to claim 1.

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