阅读说明：本技术 引入环状酰胺结构用于有机电致发光器件的化合物及应用 (Compound for introducing cyclic amide structure to organic electroluminescent device and application ) 是由 黄雨鹏 于 2020-06-12 设计创作，主要内容包括：引入环状酰胺结构用于有机电致发光器件的化合物及应用,该化合物由如下通式(Ⅰ)表示：<Image he="292" wi="700" file="DDA0002535792270000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,L<Sup>1</Sup>和L<Sup>3</Sup>相同或者不同,分别独立选自单键、C<Sub>6</Sub>～C<Sub>30</Sub>芳烃基；Ar、R<Sup>1</Sup>和R<Sup>2</Sup>分别独立选自氢、卤素及取代或未取代的C<Sub>6</Sub>～C<Sub>30</Sub>芳烃基,或者取代或未取代的C<Sub>2</Sub>～C<Sub>30</Sub>杂芳基；R<Sup>1</Sup>和R<Sup>2</Sup>相同或者不同；p为0-6的整数；q为0-5的整数；n为0-4的整数。本发明制成的稳定高效的电子传输材料,从而降低器件起亮和工作电压,提高器件效率,延长器件寿命,具有很重要的实际应用价值。(A compound for introducing a cyclic amide structure to an organic electroluminescent device and an application thereof are disclosed, wherein the compound is represented by the following general formula (I): wherein L is 1 And L 3 The same or different, are respectively and independently selected from single bond and C 6 ～C 30 An aromatic hydrocarbon group; ar, R 1 And R 2 Each independently selected from hydrogen, halogen and substituted or unsubstituted C 6 ～C 30 An aromatic hydrocarbon group, or a substituted or unsubstituted C 2 ～C 30 A heteroaryl group; r 1 And R 2 The same or different;p is an integer of 0 to 6; q is an integer of 0 to 5; n is an integer of 0 to 4. The stable and efficient electronic transmission material prepared by the invention has the advantages of reducing the lighting and working voltage of the device, improving the efficiency of the device, prolonging the service life of the device and having important practical application value.)

1. A compound for an organic electroluminescent device incorporating a cyclic amide structure, the compound being represented by the following general formula (i):

wherein L is¹And L³The same or different, are respectively and independently selected from single bond and C₆～C₃₀An aromatic hydrocarbon group;

Ar、R¹and R²Each independently selected from hydrogen, halogen and substituted or unsubstituted C₆～C₃₀An aromatic hydrocarbon group, or a substituted or unsubstituted C₂～C₃₀A heteroaryl group;

R¹and R²The same or different;

p is an integer of 0 to 6; q is an integer of 0 to 5; n is an integer of 0 to 4.

2. The compound of claim 1, wherein: c₆～C₃₀The aromatic hydrocarbon radical is C₆-C₂₀Aryl of (a); said C is₆-C₂₀Aryl of (a) is a group of the group consisting of phenyl, biphenyl, naphthyl, phenanthryl, triphenylene, fluoranthenyl; the biphenyl group is selected from the group consisting of 2-biphenyl group and 3-biphenyl group, the naphthyl group is selected from the group consisting of 1-naphthyl group and 2-naphthyl group, the phenanthryl group is selected from the group consisting of 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group and 9-phenanthryl group, and the triphenylene group is selected from the group consisting of 1-triphenylene group and 2-triphenylene group.

3. The compound of claim 1, wherein: c₂～C₃₀Heteroaryl is substituted or unsubstituted C₂～C₁₂Heteroaryl group, C₂～C₁₂Heteroaryl groups containing 1 to 2 heteroatoms selected from N, including pyridyl, pyridazinyl, pyrimidinyl, pyrazinylOxazinyl, benzimidazolyl, phenanthrothiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, phenanthroline, triazinyl, oxadiazolyl.

4. The compound of claim 1, wherein: l is¹And L³The same or different, each is independently selected from single bond, phenylene, biphenylene and naphthylene;

ar is selected from hydrogen, fluorine, chlorine, bromine, phenyl, naphthyl, biphenyl, terphenyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl, 1-triphenylene, 2-triphenylene, fluoranthenyl, pyridyl, pyridazinyl, pyrimidyl, pyrazinyl, benzimidazolyl, phenanthrothiazolyl, quinolyl, isoquinolyl, quinazolinyl, phenanthrolinyl, triazinyl, oxadiazolyl.

5. The compound of claim 1, wherein: r¹And R²Each independently selected from hydrogen, fluorine, chlorine, bromine, phenyl, naphthyl, biphenyl, terphenyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl, 1-triphenylene, 2-triphenylene, fluoranthenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, benzimidazolyl, phenanthrothiazolyl, quinolyl, isoquinolyl, quinazolinyl, phenanthroline, triazinyl, oxadiazolyl.

6. The compound of claim 1, wherein: represented by the following general formula (II):

wherein, Ar and R¹、L¹、L²P and n are as defined for formula (I).

7. The compound of claim 6, wherein: the compounds are as follows:

8. the compound of claim 1, wherein: the compound of the general formula forms a cyclic amide derivative by taking a cyclic amide structure formed by a carbazole unit as a parent nucleus, on one hand, the carbonyl group of the amide has good electron affinity so that electrons are easy to inject, on the other hand, lone-pair electrons on an N atom form accumulation through conjugated bonds, and the HOMO energy level and LUMO energy level of molecules can be adjusted by selecting substituents on the carbazole unit and a benzoyl unit, so that the carrier mobility is improved.

9. Use of a cyclic amide derivative formed from the compound according to claim 8 as an electron transport material for the preparation of an organic electroluminescent device.

10. An organic electroluminescent device formed according to the use of a cyclic amide derivative for the production of an organic electroluminescent device, characterized in that: the organic light-emitting diode comprises a substrate, and an anode layer, an organic light-emitting functional layer and a cathode layer which are sequentially formed on the substrate; the organic light-emitting functional layer comprises a hole injection layer, a hole transport layer, an organic light-emitting layer and an electron transport layer; the electron transport material of the electron transport layer comprises at least one of the cyclic amide derivative materials.

Technical Field

The invention relates to a novel organic compound and application thereof in the technical field of organic electroluminescent display.

Background

With the increasing maturity of OLED technology and the continuous push in the display field, in order to further improve the competitiveness of OLED technology, the development of OLED materials and the research of novel device structures, which can effectively improve the efficiency and the service life of OLED devices and reduce the driving voltage, have more important meanings.

The excellent new material can obviously reduce the cost of the screen body and improve the efficiency and the service life, thereby more drawing more attention to the research of people on the core material, making outstanding contribution in the aspect of the research by chemists, and designing and developing functional materials with various structures. Generally, electron transport materials are compounds having electron-deficient nitrogen-containing heterocyclic groups, such as compounds containing pyridines, quinolines, imidazoles, thiazoles, pyrimidines, and triazines, which have a high electron affinity and thus a strong ability to accept electrons. At present, the common electron transport materials are AlQ3, BPhen, BCP and some anthracene derivatives, but the efficiency and stability of the electron transport materials still need to be further improved. BPhen and BCP materials suffer from the disadvantage of being easily crystallized. Once the electron transport material is crystallized, the intermolecular charge transition mechanism is different from that of the amorphous film in normal operation, resulting in the change of electron transport properties. When the organic electroluminescent device is used, the conductivity of the whole device is changed, the mobility of electrons and hole charges in the device is unbalanced, the stability of the device is influenced, and the performance of the device is reduced and even fails.

The stable and efficient electronic transmission material is developed, so that the device lighting and working voltage is reduced, the device efficiency is improved, the device service life is prolonged, and the method has important practical application value.

Disclosure of Invention

In order to solve the above problems, the present invention provides a novel class of compounds for organic electroluminescent devices. The compound realizes good electron injection and transmission performance by introducing a novel cyclic amide structure. The compounds of the present invention are represented by the following general formula (I).

Wherein L is¹And L³The same or different, each independently selected from a single bond, C6-C30 aryl (preferably substituted)Substituted or unsubstituted C6-C20 aryl).

Ar、R¹And R²Each independently selected from hydrogen, halogen, substituted or unsubstituted C₆～C₃₀Aryl (preferably substituted or unsubstituted C)₆-C₂₀Aryl) or substituted or unsubstituted C₂～C₃₀Heteroaryl (preferably substituted or unsubstituted C)₂～C₁₂Heteroaryl, said heteroaryl preferably containing 1 to 2 heteroatoms selected from N).

R¹And R²The same or different.

p is an integer of 0 to 6; preferably 1,2, 4, 6.

q is an integer of 0 to 5; preferably 1,2, 3, 4.

n is an integer of 0 to 4; preferably 1, 2.

The halogen may be fluorine, chlorine or bromine.

As the above-mentioned C₆～C₃₀Aromatic hydrocarbon group, more preferably C₆-C₂₀Preferably said aryl group is a group of the group consisting of phenyl, biphenyl, naphthyl, phenanthryl, triphenylene, fluoranthenyl. The biphenyl group is selected from the group consisting of 2-biphenyl group and 3-biphenyl group, the naphthyl group is selected from the group consisting of 1-naphthyl group and 2-naphthyl group, the phenanthryl group is selected from the group consisting of 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group and 9-phenanthryl group, and the triphenylene group is selected from the group consisting of 1-triphenylene group and 2-triphenylene group.

As the above-mentioned C₂～C₃₀Heteroaryl, preferably substituted or unsubstituted C₂～C₁₂Heteroaryl, said heteroaryl preferably containing 1 to 2 heteroatoms selected from N, including pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, benzimidazolyl, phenanthrothiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, phenanthrolinyl, triazinyl, oxadiazolyl.

Further, L¹And L³The same or different, and are respectively and independently selected from single bond, phenylene, biphenylene and naphthylene.

Ar is selected from hydrogen, fluorine, chlorine, bromine, phenyl, naphthyl, biphenyl, terphenyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl, 1-triphenylene, 2-triphenylene, fluoranthenyl, pyridyl, pyridazinyl, pyrimidyl, pyrazinyl, benzimidazolyl, phenanthrothiazolyl, quinolyl, isoquinolyl, quinazolinyl, phenanthrolinyl, triazinyl, oxadiazolyl.

R¹And R²Each independently selected from hydrogen, fluorine, chlorine, bromine, phenyl, naphthyl, biphenyl, terphenyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9-phenanthryl, 1-triphenylene, 2-triphenylene, fluoranthenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, benzimidazolyl, phenanthrothiazolyl, quinolyl, isoquinolyl, quinazolinyl, phenanthroline, triazinyl, oxadiazolyl.

The substituents on the aromatic hydrocarbon group and the heteroaryl group, which may be the same or different, are independently selected from C6-C20 aromatic hydrocarbon groups, such as phenyl, biphenyl, terphenyl, naphthyl;

the number of the substituents is 1,2, 3, 4,5, 6 or more.

Further, it is represented by the following general formula (II).

Wherein, Ar and R¹、L¹、L²P and n are as defined for formula (I).

In the present invention, C_a-C_bThe expression (b) represents that the group has the number of carbon atoms of a to b, and generally the number of carbon atoms does not include the number of carbon atoms of the substituent unless otherwise specified.

In the present invention, the expression of chemical elements includes the concept of chemically identical isotopes, such as the expression of "hydrogen", and also includes the concept of chemically identical "deuterium" and "tritium".

The compound of the general formula uses a cyclic amide structure formed by carbazole as a mother nucleus, on one hand, the carbonyl group of amide has good electron affinity, so that the injection of electrons is easier, on the other hand, lone pair electrons on N atoms form effective accumulation through conjugated bonds in a special form, and the HOMO energy level and LUMO energy level of molecules can be adjusted through the selection of substituent groups on the carbazole unit and the benzoyl unit, so that the carrier mobility is improved.

The invention also discloses application of the cyclic amide derivative in preparing an organic electroluminescent device.

The cyclic amide derivative is used as an electron transport material.

The invention also discloses an organic electroluminescent device, which comprises a substrate, and an anode layer, an organic light-emitting functional layer and a cathode layer which are sequentially formed on the substrate;

the organic light-emitting functional layer comprises a hole injection layer, a hole transport layer, an organic light-emitting layer and an electron transport layer;

the electron transport material of the electron transport layer comprises at least one of the cyclic amide derivative materials.

Detailed Description

The organic electroluminescent compounds according to the present invention, the preparation method thereof, and the preparation method and light emitting properties of a light emitting device comprising the same are described in detail below with reference to the following examples.

Various chemicals used in the present invention, such as petroleum ether, ethyl acetate, tetrahydrofuran, n-hexane, toluene, acetic acid, methylene chloride, DMF, methyl o-iodobenzoate benzene, tetrakistriphenylphosphine palladium, dimethyl 4, 5-dibromophthalate, phenylboronic acid, p-tolylboronic acid, 2-naphthylboronic acid, p-fluorophenylboronic acid, 4-biphenylboronic acid, 4-pyridineboronic acid, 1, 2-cyclohexanedione, phenylhydrazine hydrochloride, 6-bromonaphthalen-2-ylhydrazine hydrochloride, isoamylnitrite, zinc powder, sodium sulfate, and the like, are commercially available in domestic chemical product markets.

Synthesis example 1 preparation of intermediate M1

Synthesis of intermediate M1-1: under the protection of nitrogen, 27.2 g of dioxaborolan phenylcyclohexanone (0.1mol), 28.8 g of methyl o-iodobenzoate (0.11mol), 1.15g of tetratriphenylphosphine palladium (1mmol), 31.8g of sodium carbonate (0.3mol), 150ml of toluene, 150ml of dioxane and 160ml of water are added into a three-neck flask provided with a condenser tube, the reaction system is heated under stirring to reflux, water is added for liquid separation after cooling, extraction is carried out, organic layers are combined, drying and silica gel column chromatography are carried out, and 23.5g of oily matter M1-1 is obtained.

Synthesis of intermediate M1-2: a1 liter reaction flask was charged with 14.1g (50mmol) of M1-1 prepared above and 16.4g (60mmol) of 6-bromo-2-naphthylhydrazine hydrochloride, dissolved in 200ml of ethanol, and then concentrated sulfuric acid 0.3g (3.1mmol) was added to the above solution, and the solution was stirred under reflux for 10 hours. The reaction was cooled to room temperature and the brown precipitate was filtered, washed twice with ethanol and dried under reduced pressure to give a brown solid. Dissolving the solid into a mixed solution of 200g of acetic acid and 20g of trifluoroacetic acid, stirring the reaction system at 110 ℃ for reacting for 12 hours, cooling the reaction system to room temperature, separating out light yellow solid, filtering the solid, washing the solid with acetic acid and n-hexane respectively, and purifying the solid by silica gel column chromatography to obtain 13.2 g of M1-2 as a light yellow solid intermediate with the yield of 55%.

Synthesis of intermediate M1: in a 250ml three-necked flask, 100ml dry DMF and 14.4 g M1-2(30mmol) were added, the solution was cooled to 0 ℃ and NaH (1.32g, 60% content, 33mmol) was slowly added to release a large amount of bubbles, after the addition, the reaction was stirred at low temperature for 30 minutes, then the reaction system was heated to 80 ℃ and stirred for 3 hours, and the completion of the reaction was monitored by TLC. After cooling, a saturated ammonium chloride solution is added for quenching, liquid separation and extraction are carried out, organic layers are combined, drying and column chromatography separation are carried out, and 10.4 g of intermediate M1 is obtained. The yield is 78%

Product MS (m/e): 447 elemental analysis (C27H14 BrNO): theoretical calculation value C: 72.34%, H: 3.15%, N: 3.12 percent; found value C: 72.51%, H: 3.22%, N: 3.04 percent.

Synthetic example 2 preparation of intermediate M2

Intermediate M2 was prepared according to the same procedure as in Synthesis example 1, except that the methyl o-iodobenzoate in the first step was replaced with an equivalent amount of methyl 4-chloro-2-iodobenzoate to give intermediate M2.

Product MS (m/e): 481, elemental analysis (C27H13 BrClNO): theoretical calculation value C: 67.18%, H: 2.71%, N: 2.90 percent; found value C: 67.25%, H: 2.59%, N: 2.79 percent.

Synthetic example 3 preparation of intermediate M3

Intermediate M3 was prepared in the same manner as in Synthesis example 1, except that the methyl o-iodobenzoate in the first step was replaced with an equivalent amount of methyl 4-bromo-2-iodobenzoate and the dioxaborolan phenylcyclohexanone was replaced with an equivalent amount of 4-bromo-dioxaborolan phenylcyclohexanone to give intermediate M3.

Product MS (m/e): 603, elemental analysis (C27H12Br3 NO): theoretical calculation value C: 53.50%, H: 2.00%, N: 2.31 percent; found value C: 53.44%, H: 2.02%, N: 2.36 percent.

Synthesis example 4 preparation of Compound A1

In 500ml of three with stirringTo a mouth bottle, intermediate M1(22.4g, 0.05mol), 3, 5-dichlorophenylboronic acid (19.1g, 0.055mol), Pd (PPh) were added₃)₄(1.15g, 1mmol), anhydrous sodium carbonate (10.6g, 0.1mol), toluene (100ml), ethanol (60ml), water (100 ml). Under the protection of nitrogen, the reaction mixture is mechanically uniform, and the reaction mixture is heated to reflux. And (3) refluxing for 8 hours, monitoring the reaction by TLC, stopping the reaction, and cooling. 100ml of ethyl acetate was added to the reaction system, liquid separation was performed, the aqueous phase was washed twice with 100ml of ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, then the solvent was drained off, and the residue was separated by column chromatography to give 17.1 g of pale yellow intermediate a1, yield 51%.

Product MS (m/e): 671 elemental analysis (C51H29 NO): theoretical calculation value C: 91.18%, H: 4.35%, N: 2.05 percent; found value C: 91.23%, H: 4.26%, N: 2.09.

synthesis example 5 preparation of Compound A11

Preparation of intermediate A11-1: to a 500ml three-necked flask equipped with a stirrer were added intermediate M2(24.1g, 0.05mol), (3- (3-isoquinolinyl) phenylboronic acid (13.7g, 0.055mol), Pd (PPh)₃)₄(1.15g, 1mmol), anhydrous sodium carbonate (10.6g, 0.1mol), toluene (100ml), ethanol (60ml), water (100 ml). Under the protection of nitrogen, the reaction mixture is mechanically uniform, and the reaction mixture is heated to reflux. And (3) refluxing for 5 hours, monitoring the reaction by TLC, stopping the reaction, and cooling. 100ml of ethyl acetate was added to the reaction system, liquid separation was performed, the aqueous phase was washed twice with 100ml of ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, then the solvent was drained off, and the residue was separated by column chromatography to obtain 28.7 g of pale yellow intermediate a11-1 with a yield of 86%.

Synthesis of compound a 11: a solution of A11-1(30.3g, 0.05mol), phenylboronic acid (6.7g, 0.055mol), cesium carbonate (39g, 0.12mol) and 500ml dioxane were sequentially added to a 1L three-necked flask with magnetic stirring and nitrogen substitution, and stirring was started. After nitrogen replacement again, (1.1g, 5.5mmol) tri-tert-butylphosphine and (1.27g, 2.2mmol) bis (dibenzylideneacetone) palladium were added. After the addition, the temperature is raised by heating, the temperature is controlled to be 100 ℃ for reaction for 4 hours, and the temperature is reduced after the TLC monitoring reaction is finished. Adjusting pH to neutral, separating organic phase, extracting, drying, performing column chromatography, and spin-drying solvent to obtain 28.5g pale yellow solid with yield of about 88%.

Product MS (m/e): 648; elemental analysis (C)₄₈H₂₈N₂O): theoretical value C: 88.87%, H: 4.35%, N: 4.32 percent; found value C: 89.01%, H: 4.28%, N: 4.35 percent

Synthesis example 6 preparation of Compound A25

To a 1000ml three-necked flask equipped with a stirrer were added intermediate M3(30.3g, 0.05mol), 4-pyridineboronic acid (24.6g, 0.2mol), Pd (PPh)₃)₄(3.45g, 3mmol), anhydrous sodium carbonate (31.8g, 0.3mol), toluene (150ml), ethanol (80ml), water (150 ml). Under the protection of nitrogen, the reaction mixture is mechanically uniform, and the reaction mixture is heated to reflux. And (3) refluxing for 5 hours, monitoring the reaction by TLC, stopping the reaction, and cooling. 200ml of toluene was added to the reaction system, liquid separation was performed, the aqueous phase was washed twice with 100ml of toluene, the organic phases were combined, dried over anhydrous sodium sulfate, then the solvent was drained off, and the residue was separated by column chromatography to give 22.5 g of pale yellow intermediate A25, yield 75%.

Product MS (m/e): 600, preparing a mixture; elemental analysis (C)₄₂H₂₄N₄O): theoretical value C: 83.98%, H: 4.03%, N: 9.33 percent; found value C: 84.01%, H: 4.21%, N: 9.35 percent

Device application example

In order to further illustrate the application of the material of the invention as an electron transport material in an OLED device and compare the performance of the material with the performance of a common electron transport material, the invention adopts the following simple electroluminescent device, and the specific structure of the organic electroluminescent device in the application example of the device of the invention is as follows:

ITO/2-TNATA/NPB/CBP:(piq)2Ir(acac)(1:5％)/ETL/LiF/Al

the hole injection material adopts 2-TNATA; the hole transport material used was commonly used NPB; the material of the luminescent layer uses red phosphorescent dye (piq)₂Ir (acac), collocated with a red light subject CBP; the electron transport layer used for comparison is made of a common electron transport material Bphen. The structural formula of the material used for each functional layer is as follows:

the substrate may be a substrate used in a conventional organic light emitting device, for example: glass or plastic. In the invention, the glass substrate and the ITO are used as anode materials in the manufacture of the organic electroluminescent device.

Various triarylamine materials can be used for the hole transport layer, and the hole transport material selected for use in the fabrication of the organic electroluminescent device of the present invention is NPB.

The cathode can adopt metal and a mixture structure thereof, such as Mg: Ag, Ca: Ag and the like, and can also be an electron injection layer/metal layer structure, such as common cathode structures of LiF/Al, Li2O/Al and the like. The cathode material selected in the preparation of the organic electroluminescent device is LiF/Al.

Device example 1 compound a1 of the invention was used as an electron transport material:

the ITO (150nm) transparent conductive layer coated glass plate was sonicated in a commercial detergent, rinsed in deionized water, washed in acetone: ultrasonically removing oil in an ethanol mixed solvent (volume ratio is 1: 1), baking in a clean environment until water is completely removed, cleaning by using ultraviolet light and ozone, and bombarding the surface by using low-energy cationic beams;

placing the glass substrate with the anode in a vacuum chamber, and vacuumizing to 1 × 10^-5-9×10^-3Pa, evaporating a compound 2-TNATA on the anode layer film in vacuum to form a hole injection layer with the thickness of 60 nm; evaporating a compound NPB on the hole injection layer in vacuum to form a hole transport layer with the thickness of 20nm, wherein the evaporation rate is 0.1 nm/s;

forming an electroluminescent layer on the hole transport layer, and specifically operating as follows: will be used as the host material CBP [4,4' -N ] of the luminescent layerN' -dicarbazole-biphenyl was placed in the cell of a vacuum vapor deposition apparatus to be used as a dopant (piq)₂Ir (acac) [ bis- (1-phenylisoquinolinyl) acetylacetonatoiridium (III)]Placing in another chamber of the vacuum vapor deposition apparatus, simultaneously evaporating two materials at different rates, (piq)₂The concentration of Ir (acac) is 5 percent, and the total film thickness of evaporation plating is 30 nm;

vacuum evaporating the compound A1 of the invention on the luminescent layer to form an electron transport layer with a thick film of 20nm, wherein the evaporation rate is 0.1 nm/s;

LiF with the thickness of 0.5nm is vacuum-evaporated on the Electron Transport Layer (ETL) to be used as an electron injection layer, and an Al layer with the thickness of 150nm is used as a cathode of the device.

And carrying out packaging test on the prepared device.

Device example 2 compound a2 of the invention was used as an electron transport material:

referring to the preparation method of device example 1, compound a2 of the present invention was used instead of compound a1 as an electron transporting material.

Device example 3 compound A8 of the invention was used as an electron transport material:

referring to the preparation method of device example 1, compound A8 of the present invention was used instead of compound a1 as an electron transporting material.

Device example 4 compound a13 of the invention was used as an electron transport material:

referring to the preparation method of device example 1, compound a13 of the present invention was used instead of compound a1 as an electron transporting material.

Device example 5 compound a20 of the invention was used as an electron transport material:

referring to the preparation method of device example 1, compound a20 of the present invention was used instead of compound a1 as an electron transporting material.

Device example 6 compound a26 of the invention was used as an electron transport material:

referring to the preparation method of device example 1, compound a26 of the present invention was used instead of compound a1 as an electron transporting material.

Comparative device example 1 use of Bphen as an electron transport material

Referring to the preparation method of device example 1, compound Bphen was used as an electron transport material instead of compound a 1.

Comparative device example 2 use B as an electron transport material

Referring to the preparation method of device example 1, compound B was used as an electron transport material instead of compound a 1.

The voltage and current efficiencies of the organic electroluminescent devices prepared in the respective application examples were measured at the same luminance, and the measurement results are shown in table 1 below.

TABLE 1 results of measurements of devices using the compounds of the invention as electron transport layers and/or as luminescent host materials

From the experimental data in table 1, compared with the comparative device examples 1 and 2, the novel organic material of the present invention is used as an electron transport material in an organic electroluminescent device, can effectively reduce the working voltage of the device, improve the current efficiency, and is an electron transport material with good performance. This is related to the higher electron affinity and the higher electron mobility and the good thermal stability of the material of the present invention.

The above examples only list the effect data of A1, A2, A8, A13, A20 and A26, which are representative sampling tests, and the overall data are not very different from each other by experimental data, and can directly represent the effects of other non-listed A3-A7, A9-A12, A14-A19, A21-A25 and A27-A28.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.