Hexobenzocoronene molecule, synthetic method thereof and application of hexobenzocoronene molecule in electroluminescent device

Abstract

The invention discloses a hexabenzocoronene molecule, a synthesis method thereof and an application of the hexabenzocoronene molecule in an electroluminescent device, and belongs to the technical field of organic photoelectric materials. According to the invention, hole injection can be effectively improved through stacking of the hexabenzoquinone molecules and pi electron delocalization with large center and strong plane, so that the efficiency of a device doped with the molecules is greatly improved compared with that of a non-doped contrast device, the method is a new way for improving hole injection, and the molecules have the advantages of easy synthesis, low cost and high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of organic optoelectronic materials, and particularly to a hexa-peri-hexabenzocoronene molecule, a synthesis method thereof, and an application thereof in an electro-optic device. Background Art

[0002] Since the cathode ray tube (CRT) was first applied to a display in 1922, display technology has undergone several revolutions. Liquid crystal display (LCD) comprehensively surpasses CRT display devices in terms of comprehensive performance such as brightness, contrast, power consumption, lifespan, volume, and weight. Currently, organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs) are electro-luminescent diodes that utilize self-luminescence, do not require a backlight source, have a wider color gamut, richer and more vivid colors, and high contrast, and are currently research hotspots in the display field.

[0003] However, the efficiency of blue QLEDs lags behind that of green and red LEDs to a certain extent, restricting their application in full-color displays. Such devices generally adopt a sandwich structure, including: an anode, a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode. From the structural characteristics, it can be seen that one of the main obstacles to the low efficiency of electro-optic devices such as QLEDs and OLEDs is the serious non-radiative recombination caused by unbalanced charge injection. Commonly used hole transport materials (HTMs) (such as poly[(9,9-dioctylfluorene-2,7-diyl)-alt-(4,4'-(N-(4-butylphenyl))(TFB)), poly-N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (poly-tpd)), poly-N-vinylcarbazole (PVK)) have a mobility of about 10 -6 -10 -3 cm 2 V -1 s -1 which is much lower than that of electron transport materials (such as zinc oxide (ZnO), magnesium-doped zinc oxide (Zn 1-X Mg X O)) at 10 -3 -10 -2 cm 2 V - 1 s -1 . By comparing the mobilities, it can be concluded that insufficient hole injection is the main cause of charge imbalance.

[0004] Previous studies have added discotic molecules of benzophenanthrene to the HTL, and these molecules form stacks with excellent hole mobility (2.6×10 -2 cm 2 V -1 s -1The hole transport channels of ( ). The hole mobility of the composite HTM is increased from 10 -4 to 10 -3 cm 2 V -1 s -1 , and the external quantum efficiency (EQE) of the device reaches 18.59%, showing a significant improvement compared with the undoped efficiency. [1] There are also methods to promote charge balance by inserting a layer of polymethyl methacrylate (PMMA) between the EML and the ETL to block excessive electrons, resulting in a longer fluorescence lifetime and higher efficiency.

[0005] The present invention discovers that the stacking of hexa-peri-hexabenzocoronene molecules and the strong π-electron delocalization in the central large plane can effectively improve hole injection, enabling a significant increase in the efficiency of the device doped with such molecules compared to the undoped control device. This is a new way to enhance hole injection, and such molecules have the advantages of easy synthesis, low cost, and high yield. Summary of the Invention

[0006] The purpose of the present invention is to provide a hexa-peri-hexabenzocoronene molecule, its synthesis method, and its application in electro-optic devices. For the first time, such molecules are applied to QLEDs, and are mixed with hole transport materials to prepare a hole transport layer to balance carriers and improve the device efficiency.

[0007] To achieve the above purpose, the present invention discloses a hexa-peri-hexabenzocoronene molecule, and the structural formula of the hexa-peri-hexabenzocoronene molecule is shown as follows:

[0008]

[0009] In the above structural formula, R1 and R2 are the same or different groups; R1 and R2 are any one of the following groups:

[0010]

[0011]

[0012] Among them, R is a long straight-chain alkyl or long straight-chain alkoxy group with a chain length of C1-C20. Therefore, the hexa-peri-hexabenzocoronene molecules in the present invention include but are not limited to the following molecules:

[0013]

[0014]

[0015]

[0016] The present invention also provides a synthesis method of the above hexa-peri-hexabenzocoronene molecule. When R1 and R2 are the same substituents, the synthesis of the hexa-peri-hexabenzocoronene molecule includes the following steps:

[0017] (1) Mix iodobenzene or iodobenzene derivative with a catalyst in triethylamine solvent, deoxygenate the reaction system, and dropwise add phenylacetylene or phenylacetylene derivative under the protection of an inert gas. After the addition is complete, react at room temperature for 10 - 15 h. After the reaction is complete, wash with saturated brine, extract with dichloromethane, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography to obtain the first intermediate;

[0018] (2) Mix the first intermediate with the catalyst dicobalt octacarbonyl in 1,4 - dioxane solvent, and react at 100 - 130 °C for 8 - 16 h under the protection of an inert gas. After the reaction is complete, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography to obtain the second intermediate;

[0019] (3) Under the protection of an inert gas, using the second intermediate as the raw material, bubble for 1 h with anhydrous dichloromethane as the solvent, then add a nitromethane solution of iron(III) chloride and stir to react for 4 - 6 h. After the reaction is complete, quench with ice methanol, filter the precipitate precipitated from ice methanol, and obtain the third intermediate, i.e., hexa-peri-hexabenzocoronene molecule, through silica gel column chromatography.

[0020] Preferably, the molar ratio of iodobenzene or iodobenzene derivative to phenylacetylene or phenylacetylene derivative is 1:(1 - 1.5). Both the iodobenzene derivative and the phenylacetylene derivative contain an R1 group or an R2 group, and the R1 group or the R2 group is not a hydrogen group;

[0021] The R1 group or the R2 group on the iodobenzene derivative and the phenylacetylene derivative is located at the 4th position of the iodobenzene and the 4th position of the phenylacetylene.

[0022] Preferably, in step (1), the catalyst is cuprous iodide and bis(triphenylphosphine)palladium dichloride. The mass - volume ratio of iodobenzene or iodobenzene derivative to triethylamine is 1 g:30 - 100 ml, and the molar ratio of iodobenzene or iodobenzene derivative to cuprous iodide and bis(triphenylphosphine)palladium dichloride is 1:(0.02 - 0.1):(0.02 - 0.1);

[0023] In step (2), the mass - volume ratio of the first intermediate to 1,4 - dioxane is 1 g:(20 ml - 100 ml), and the molar ratio of the first intermediate to dicobalt octacarbonyl is 1:(0.05 - 0.1);

[0024] In step (3), the mass - volume ratio of the second intermediate to anhydrous dichloromethane is 1 g:(20 ml - 100 ml), and the molar ratio of the second intermediate to iron(III) chloride is 1:(10 - 30).

[0025] When R1 and R2 are different substituents, the synthesis method of the hexa-peri-hexabenzocoronene molecule provided by the present invention is different from the above method and includes the following steps:

[0026] (1) Under the protection of inert gas, using benzil or benzil derivative and 1,3-diphenylacetone or 1,3-diphenylacetone derivative with a molar ratio of 1:1 as raw materials, ethanol as the solvent, after heating to reflux, add an ethanol solution of potassium hydroxide, react at 90 - 110 °C for 0.1 - 0.5 h, and after the reaction ends, filter and wash to obtain the fourth intermediate;

[0027] (2) Under the protection of inert gas, using the fourth intermediate and p-bromoacetylene with a molar ratio of 1:1.5 as raw materials, diphenyl ether as the solvent, react at 200 - 280 °C for 18 - 30 h, perform post-treatment, and obtain the fifth intermediate through silica gel column chromatography;

[0028] (3) Under the protection of inert gas, using the fifth intermediate as the raw material, anhydrous dichloromethane as the solvent, bubble for 1 h at room temperature, then add a nitro-methane solution of ferric chloride, react at room temperature for 4 - 6 h, quench with ice methanol, filter the precipitate, wash with ice methanol, and obtain the sixth intermediate through silica gel column chromatography;

[0029] (4) Under the protection of inert gas, using the sixth intermediate and boric acid or boric acid derivative with a molar ratio of 1:(2 - 4) as raw materials, water and tetrahydrofuran as solvents, tetrakis(triphenylphosphine)palladium as the catalyst, potassium carbonate as the base, react at 60 - 80 °C for 12 - 52 h, wash with saturated brine, extract with dichloromethane, evaporate the solvent under reduced pressure, and obtain the seventh intermediate, namely hexa-peri-hexabenzocoronene molecules, through silica gel column chromatography.

[0030] Preferably, both the benzil derivative and the 1,3-diphenylacetone derivative contain an R1 group, and the R1 group is not a hydrogen group;

[0031] The R1 groups on the benzil derivative and the 1,3-diphenylacetone derivative are located at the 4th position of the benzene ring on benzil and the 4th position of the benzene ring on 1,3-diphenylacetone.

[0032] Preferably, the boric acid derivative contains an R2 group, and the R2 group is not a hydrogen group.

[0033] In step (1), the mass-volume ratio of benzil or benzil derivative to ethanol is 1 g:10 - 50 ml, and the molar ratio of potassium hydroxide to benzil or benzil derivative is (0.05 - 0.1):1;

[0034] In step (2), the mass-volume ratio of the fourth intermediate to diphenyl ether is 1 g:10 - 50 ml;

[0035] In step (3), the mass-volume ratio of the fifth intermediate to anhydrous dichloromethane is 1 g:(30 - 100) ml, and the molar ratio of ferric chloride to the fifth intermediate is (10 - 30):1;

[0036] In step (4), the mass-volume ratio of the sixth intermediate to the solvent is 1 g:(30 - 100) ml, the molar ratio of the sixth intermediate to the catalyst is 1:(0.05 - 0.2), and the molar ratio of the sixth intermediate to potassium carbonate is 1:(5 - 20).

[0037] The present invention also provides an application of the above-mentioned hexa-peri-hexabenzocoronene molecule in an electro-optic device. The hexa-peri-hexabenzocoronene molecule is applied to a functional layer of the electro-optic device. The hexa-peri-hexabenzocoronene molecule can be used alone as the functional layer or can be doped with the original functional layer to form a new functional layer.

[0038] Therefore, the present invention has the following beneficial effects:

[0039] 1. The synthesis route of the hexa-peri-hexabenzocoronene molecule provided by the present invention is fixed, and only the substituents need to be replaced, with rich molecular diversity.

[0040] 2. The synthesis method provided by the present invention has low cost and high yield, and the hexa-peri-hexabenzocoronene molecule can be stably synthesized under this synthesis method.

[0041] 3. When the hexa-peri-hexabenzocoronene molecule provided by the present invention is applied to a QLED, due to different stacking modes of different substituent molecules of the hexa-peri-hexabenzocoronene molecule and strong π-electron delocalization of the central large plane, the hole injection can be effectively improved, and the device efficiency can be improved.

[0042] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is the ultraviolet-visible absorption diagram of the solution prepared from the hexa-peri-hexabenzocoronene molecules prepared in Examples 1 - 2.

[0044] Figure 2 It is the ultraviolet-visible absorption diagram of the thin film prepared from the hexa-peri-hexabenzocoronene molecules prepared in Examples 1 - 2.

[0045] Figure 3 It is the fluorescence spectrum of the hexa-peri-hexabenzocoronene molecules prepared in Examples 1 - 2.

[0046] Figure 4 It is the thermogravimetric analysis spectrum of the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1.

[0047] Figure 5 It is the differential scanning calorimetry diagram of the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1.

[0048] Figure 6 Thermogravimetric analysis spectrum of the hexa-peri-hexabenzocoronene molecule TM21 prepared in Example 2.

[0049] Figure 7 Differential scanning calorimetry chart of the hexa-peri-hexabenzocoronene molecule TM21 prepared in Example 2.

[0050] Figure 8 Schematic diagram of the structure of the QLED device in the application example.

[0051] Figure 9 Current density-voltage-brightness graph of the QLED devices in Application Examples 1-6.

[0052] Figure 10 External quantum efficiency-brightness graph of the QLED devices in Application Examples 1-6. Detailed implementation manners

[0053] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains.

[0054] The present invention discloses a hexa-peri-hexabenzocoronene molecule, and the structural formula of the hexa-peri-hexabenzocoronene molecule is shown as follows:

[0055]

[0056] In the above structural formula, R1 and R2 are the same or different groups; R1 and R2 are any one of the following groups:

[0057]

[0058] Among them, R is a long straight-chain alkyl or long straight-chain alkoxy group with a chain length of C1-C20.

[0059] Therefore, the hexa-peri-hexabenzocoronene molecules in the present invention include but are not limited to the following molecules:

[0060]

[0061]

[0062]

[0063] The present invention also provides a synthesis method of the above-mentioned hexa-peri-hexabenzocoronene molecule. When R1 and R2 are the same substituents, the synthesis of the hexa-peri-hexabenzocoronene molecule includes the following steps:

[0064] (1) Mix iodobenzene or iodobenzene derivatives with a catalyst in a triethylamine solvent, deoxygenate the reaction system, and dropwise add phenylacetylene or phenylacetylene derivatives under the protection of an inert gas. After the addition is complete, react at room temperature for 10 - 15 h. After the reaction is complete, wash with saturated brine, extract with dichloromethane, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography to obtain the first intermediate;

[0065] (2) Mix the first intermediate with the catalyst dicobalt octacarbonyl in a 1,4 - dioxane solvent and react at 100 - 130 °C for 8 - 16 h under the protection of an inert gas. After the reaction is complete, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography to obtain the second intermediate;

[0066] (3) Under the protection of an inert gas, using the second intermediate as the raw material, bubble in anhydrous dichloromethane solvent for 1 h, then add a nitromethane solution of iron(III) chloride and stir to react for 4 - 6 h. After the reaction is complete, quench with ice methanol, filter the precipitate precipitated from ice methanol, and obtain the third intermediate, namely the hexa-peri-hexabenzocoronene molecule, through silica gel column chromatography.

[0067] The molar ratio of iodobenzene or iodobenzene derivatives to phenylacetylene or phenylacetylene derivatives is 1:(1 - 1.5). Both iodobenzene derivatives and phenylacetylene derivatives contain an R1 group or an R2 group, and the R1 group or the R2 group is not a hydrogen group;

[0068] The R1 group or R2 group on the iodobenzene derivative and the phenylacetylene derivative is located at the 4th position of iodobenzene and the 4th position of phenylacetylene.

[0069] In step (1), the catalyst is copper(I) iodide and bis(triphenylphosphine)palladium(II) dichloride. The mass - volume ratio of iodobenzene or iodobenzene derivatives to triethylamine is 1 g:30 - 100 ml, and the molar ratio of iodobenzene or iodobenzene derivatives to copper(I) iodide and bis(triphenylphosphine)palladium(II) dichloride is 1:(0.02 - 0.1):(0.02 - 0.1).

[0070] In step (2), the mass - volume ratio of the first intermediate to 1,4 - dioxane is 1 g:(20 ml - 100 ml), and the molar ratio of the first intermediate to dicobalt octacarbonyl is 1:(0.05 - 0.1).

[0071] In step (3), the mass - volume ratio of the second intermediate to anhydrous dichloromethane is 1 g:(20 ml - 100 ml), and the molar ratio of the second intermediate to iron(III) chloride is 1:(10 - 30).

[0072] When R1 and R2 are different substituents for the hexa-peri-hexabenzocoronene molecule provided by the present invention, the synthesis method is different from the above method and includes the following steps:

[0073] (1) Under the protection of inert gas, using benzil or benzil derivatives and 1,3-diphenylacetone or 1,3-diphenylacetone derivatives with a molar ratio of 1:1 as raw materials, ethanol as the solvent, after heating under reflux, an ethanol solution of potassium hydroxide is added, and the reaction is carried out at 90 - 110 °C for 0.1 - 0.5 h. After the reaction is completed, the fourth intermediate is obtained after filtration and washing;

[0074] (2) Under the protection of inert gas, using the fourth intermediate and p-bromo-phenylacetylene with a molar ratio of 1:1.5 as raw materials, diphenyl ether as the solvent, the reaction is carried out at 200 - 280 °C for 18 - 30 h, and after post-treatment, the fifth intermediate is obtained through silica gel column chromatography;

[0075] (3) Under the protection of inert gas, using the fifth intermediate as the raw material, anhydrous dichloromethane as the solvent, after bubbling at room temperature for 1 h, a nitromethane solution of ferric chloride is added, and the reaction is carried out at room temperature for 4 - 6 h. Ice methanol is added to quench, the precipitate is filtered, washed with ice methanol, and the sixth intermediate is obtained through silica gel column chromatography;

[0076] (4) Under the protection of inert gas, using the sixth intermediate and boric acid or boric acid derivatives with a molar ratio of 1:(2 - 4) as raw materials, water and tetrahydrofuran as solvents, tetrakis(triphenylphosphine)palladium as the catalyst, potassium carbonate as the base, the reaction is carried out at 60 - 80 °C for 12 - 52 h, washed with saturated brine, extracted with dichloromethane, the solvent is removed by evaporation under reduced pressure, and the seventh intermediate, namely hexahelicene molecules, is obtained through silica gel column chromatography.

[0077] Both benzil derivatives and 1,3-diphenylacetone derivatives contain an R1 group, and the R1 group is not a hydrogen group; the R1 groups on the benzil derivatives and 1,3-diphenylacetone derivatives are located at the 4th position of the benzene ring on benzil and the 4th position of the benzene ring on 1,3-diphenylacetone.

[0078] The boric acid derivative contains an R2 group, and the R2 group is not a hydrogen group.

[0079] In step (1), the mass-volume ratio of benzil or benzil derivatives to ethanol is 1 g:10 - 50 ml, and the molar ratio of potassium hydroxide to benzil or benzil derivatives is (0.05 - 0.1):1.

[0080] In step (2), the mass-volume ratio of the fourth intermediate to diphenyl ether is 1 g:10 - 50 ml.

[0081] In step (3), the mass-volume ratio of the fifth intermediate to anhydrous dichloromethane is 1 g:(30 - 100) ml, and the molar ratio of ferric chloride to the fifth intermediate is (10 - 30):1.

[0082] In step (4), the mass-volume ratio of the sixth intermediate to the solvent is 1 g:(30 - 100) ml, the molar ratio of the sixth intermediate to the catalyst is 1:(0.05 - 0.2), and the molar ratio of the sixth intermediate to potassium carbonate is 1:(5 - 20).

[0083] The present invention also provides an application of the above-mentioned hexabenzocoronene molecule in an electro-optic device. The hexabenzocoronene molecule is applied to the functional layer of the electro-optic device. This hexabenzocoronene molecule can be used alone as the functional layer or, after doping with the original functional layer, used as a new functional layer.

[0084] The technical solution of the present invention will be further described below with reference to the drawings and embodiments.

[0085] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. These other embodiments are also covered by the protection scope of the present invention.

[0086] Example 1

[0087] This example provides a hexabenzocoronene molecule, and its synthesis method is as follows:

[0088] The first step:

[0089]

[0090] Add 1-tert-butyl-4-iodobenzene (1.00 g, 3.84 mmol), copper(I) iodide (17.50 mg, 91.89 μmol), bis(triphenylphosphine)palladium(II) dichloride (18.10 mg, 25.79 μmol) and 50 ml of triethylamine into a 100 ml two-necked flask. Deoxygenate the reaction system, and dropwise add 4-tert-butylphenylacetylene (608.35 mg, 3.84 mmol) drop by drop under argon protection. After the addition is complete, react at room temperature for 10 h. Monitor the reaction by thin-layer chromatography (developer: petroleum ether). After the reaction is complete, wash with saturated brine, extract with dichloromethane, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography (eluent: petroleum ether) to obtain 0.9563 g of white solid compound 1-1, with a yield of 85.74%. The proton nuclear magnetic resonance spectrum and carbon spectrum are as follows:

[0091] 1 H NMR(400MHz,Chloroform-d)δ7.38(d,J=8.3Hz,4H),7.27(d,J=8.3Hz,4H),1.24(s,18H).

[0092] 13 C NMR (101 MHz, CDCl3) δ 151.32, 131.30, 125.32, 120.48, 88.87, 77.35, 77.03, 76.72, 34.79, 31.21.

[0093] Step 2:

[0094]

[0095] Add compound 1-1 (0.87 g, 3.00 mmol), dicobalt octacarbonyl (153.88 mg, 0.45 mmol) and 30 ml of 1,4-dioxane into a 50 ml two-necked flask. React at 115 °C for 10 h under argon protection. Monitor the reaction by thin-layer chromatography (developing solvent: petroleum ether:dichloromethane = 5:1, V / V). After the reaction is complete, evaporate the solvent under reduced pressure. The crude product is separated and purified by silica gel column chromatography (eluent: petroleum ether:dichloromethane = 8:1, V / V) to obtain 0.6645 g of white solid 1-2 with a yield of 76.38%. The 1H NMR and 13C NMR spectra are as follows:

[0096] 1 H NMR (400 MHz, Chloroform-d) δ 6.81 (d, J = 8.3 Hz, 2H), 6.68 (d, J = 8.3 Hz, 2H), 1.10 (s, 9H).

[0097] 13 C NMR (101 MHz, CDCl3) δ 147.32, 140.27, 137.97, 131.09, 123.01, 77.34, 77.02, 76.70, 34.05, 31.20.

[0098] Step 3:

[0099]

[0100] Add compound 1-2 (0.87 g, 1.00 mmol) and 50 ml of anhydrous dichloromethane into a 100 ml three-necked flask. After bubbling for 1 h, add a nitromethane solution of iron(III) chloride (3.24 g, 20 mmol, 3 ml), and stir at room temperature for 4 h. Monitor the reaction by thin-layer chromatography (developing solvent: petroleum ether:dichloromethane = 5:1, V / V). After the reaction is complete, quench with ice methanol, filter the precipitate precipitated from ice methanol, and separate and purify by silica gel column chromatography to obtain 0.71 g of yellow solid compound 1-3, numbered TM1 (HBC-t-Bu), with a yield of 82.82%. The 1H NMR and 13C NMR spectra are as follows:

[0101] 1 H NMR (400 MHz, Methylene Chloride-d2) δ 9.28 (s, 2H), 1.75 (s, 9H).

[0102] 13 C NMR (101 MHz, CD2Cl2) δ 149.39, 130.38, 123.74, 120.39, 119.16, 54.01, 53.74, 53.47, 53.20, 52.93, 35.68, 31.70.

[0103] Example 2

[0104] This example provides a hexa-peri-hexabenzocoronene molecule, and its synthesis method is as follows:

[0105] The first step:

[0106]

[0107] Add 1,2-bis(4-(tert-butyl)phenyl)ethane-1,2-dione (1.00 g, 3.10 mmol), 1,3-bis(4-(tert-butyl)phenyl)propan-2-one (1.00 g, 3.10 mmol) and 10 ml of ethanol into a 50 ml two-necked flask. After heating to reflux, quickly add an ethanol solution of KOH (0.09 g, 0.50 ml) and heat for 15 minutes. After the reaction is complete, cool the mixture, filter the precipitate, and wash it with ice ethanol to obtain 1.55 g of a dark purple solid compound 2-1, with a yield of 82.36%. The 1H NMR and 13C NMR spectra are as follows:

[0108] 1 H NMR (800 MHz, Chloroform-d) δ 7.18 (d, J = 8.2 Hz, 4H), 7.14 (d, J = 8.1 Hz, 4H), 7.08 (d, J = 7.9 Hz, 4H), 6.76 (d, J = 7.9 Hz, 4H), 1.22 (s, 18H), 1.20 (s, 18H).

[0109] 13 C NMR (201 MHz, CDCl3) δ 201.41, 154.26, 151.34, 150.02, 130.49, 129.64, 129.07, 128.12, 124.91, 124.56, 124.28, 34.66, 34.57, 31.27, 31.25.

[0110] The second step:

[0111]

[0112] In a 50 ml two-necked flask, compound 2-1 (1.2178 g, 2.00 mmol), bis(4-bromophenyl) acetylene (0.8065 g, 2.40 mmol) and 15 ml of diphenyl ether were added. The reaction system was deoxygenated and heated to 250 °C under argon protection and refluxed for 20 h. The reaction was monitored by thin-layer chromatography (developing agent: petroleum ether:dichloromethane = 8:1, V / V). After the reaction was complete, it was cooled to room temperature, recrystallized from methanol, the precipitate was filtered, and washed with ice-cold methanol to obtain 1.49 g of off-white solid compound 2-2, with a yield of 81.29%. The 1H NMR and 13C NMR spectra are as follows:

[0113] 1 H NMR (400 MHz, Chloroform-d) δ 7.00 (d, J = 8.4 Hz, 4H), 6.85 (d, J = 8.3 Hz, 4H), 6.80 (d, J = 8.3 Hz, 4H), 6.66 (dt, J = 16.3, 8.3 Hz, 12H), 1.12 (s, 18H), 1.09 (s, 18H).

[0114] 13 C NMR (101 MHz, CDCl3) δ 148.00, 147.61, 141.30, 140.40, 139.73, 138.35, 137.47, 137.21, 133.12, 130.92, 130.86, 129.87, 123.45, 123.11, 119.45, 77.34, 77.03, 76.71, 34.15, 31.20.

[0115] Step 3:

[0116]

[0117] In a 100 ml three-necked flask, compound 2-2 (0.9169 g, 1.00 mmol) and 50 ml of dichloromethane were added. After bubbling for 1 h at room temperature, a nitromethane solution of iron(III) chloride (3.2438 g, 20.00 mmol, 2.00 ml) was added and bubbling was continued for 2 h at room temperature. The reaction was monitored by thin-layer chromatography (developing agent: petroleum ether:dichloromethane = 3:1, V / V). After the reaction was complete, ice-cold methanol was added to quench the reaction, the precipitate was filtered, and washed with ice-cold methanol. The solid precipitate was added to a short column and eluted with dichloromethane to obtain 0.46 g of yellow solid compound 2-3, with a yield of 50.61%. The 1H NMR spectrum is as follows:

[0118] 1HNMR(400MHz, Chloroform-d) δ 8.99 (s, 2H), 8.70 (s, 2H), 8.39 (s, 2H), 7.85 (s, 2H), 7.36 (s, 2H), 7.04 (s, 2H), 2.02 (s, 18H), 1.80 (s, 18H).

[0119] Step 4:

[0120]

[0121] Add compound 2-3 (0.9048 g, 1.00 mmol), (3,5-di-tert-butylphenyl)boronic acid (0.9366 g, 4.00 mmol), tetrakis(triphenylphosphine)palladium(0) (0.5778 g, 0.5 mmol), potassium carbonate (1.3820 g, 10.00 mmol), 3 ml of water and 50 ml of tetrahydrofuran into a 100 ml three-necked flask. Heat to 70 °C under argon protection and react for 48 h. Monitor the reaction by thin-layer chromatography (developing solvent: petroleum ether:dichloromethane = 2:1, V / V). After the reaction is complete, wash with saturated brine, extract with dichloromethane, evaporate the solvent under reduced pressure, and purify the crude product by silica gel column chromatography (eluent: petroleum ether:dichloromethane = 5:1, V / V) to obtain the yellow solid compound 2-4, numbered TM21 (HBC-2Ph2tBu), with a total of 0.4632 g and a yield of 41.22%. The 1H NMR and 13C NMR spectra are as follows:

[0122] 1 H NMR(400MHz, Chloroform-d) δ 9.52 (s, 1H), 9.49 (s, 1H), 9.38 (s, 1H), 9.33 (s, 3H), 7.97 (s, 2H), 7.66 (s, 1H), 1.84 (s, 9H), 1.81 (s, 9H), 1.55 (s, 18H).

[0123] 13 C NMR(151MHz, Chloroform-d) δ 151.73, 149.16, 149.10, 141.64, 140.53, 131.21, 130.97, 130.57, 130.52, 130.50, 130.26, 124.99, 123.97, 123.89, 122.68, 121.85, 121.31, 121.27, 120.78, 120.71, 120.53, 119.20, 118.94, 118.90, 50.84, 35.75, 35.74, 35.25, 32.03, 31.97, 31.70.

[0124] The TM1 and TM21 prepared in the above Examples 1-2 were made into 1×10 -5 mol / l solutions and 5 mg / ml solutions and spin-coated into films (rotation speed 4000 rpm, time 30 s, acceleration 2000 rpm / s). The corresponding UV-Vis absorption diagrams of the solutions are as shown in Figure 1 and the corresponding UV-Vis absorption diagrams of the films are as shown in Figure 2 . As can be seen from Figure 1 , the maximum absorption wavelengths of the molecules are 226 nm and 240 nm in sequence, corresponding to the π-π* transitions in the molecules. Due to the stacking between molecules, the maximum absorption wavelength of the molecules shown in the film in Figure 2 is redshifted compared to the maximum absorption wavelength of the molecules shown in the solution in Figure 1 .

[0125] The fluorescence diagrams of the hexa-peri-hexabenzocoronene molecules TM1 and TM21 prepared in Examples 1-2 are as shown in Figure 3 , and the maximum emission peak wavelengths are 484 nm and 491 nm in sequence.

[0126] The thermogravimetric analysis diagram of the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1 is as shown in Figure 4 , and the differential scanning calorimetry diagram is as shown in Figure 5 . The thermal decomposition temperature is 487 °C, there is no phase change, and the thermal stability is good.

[0127] The thermogravimetric analysis diagram of the hexa-peri-hexabenzocoronene molecule TM21 prepared in Example 2 is as shown in Figure 6 , and the differential scanning calorimetry diagram is as shown in Figure 7 . The thermal decomposition temperature is 498 °C, there is no phase change, and the thermal stability is good.

[0128] Application Example 1

[0129] In this application example, the hexa-peri-hexabenzocoronene molecule TM1 prepared in the above Example 1 was doped into the PVK solution as a hole transport layer to prepare a QLED device. The structure of this QLED device is as shown in Figure 8 , and its preparation method is as follows:

[0130] (1) The ITO glass substrate was ultrasonically cleaned with a cleaning agent, deionized water, deionized water, recycled ethanol, and absolute ethanol for 20 min each. The beaker containing the ITO glass and absolute ethanol was placed on a hot plate and the temperature was set to 140 °C. When the absolute ethanol reached a slightly boiling state, the solvent on the surface of the ITO glass was blown away with a nitrogen gas stream. Subsequently, the dried ITO glass was cleaned with an oxygen plasma cleaner for 10 min to obtain a pretreated ITO substrate. After diluting the PEDOT:PSS 8000 solution with absolute ethanol in a ratio of 3:7, it was filtered with a disposable needle filter. Each time, 40 μl of the filtered PEDOT:PSS 8000 solution was spin-coated on the pretreated ITO substrate at a speed of 4000 rpm / min for 30 s, and then transferred to a hot plate at 140 °C for annealing for 20 min to form a hole injection layer on the surface of the pretreated ITO substrate.

[0131] (2) A 10 mg / ml PVK chlorobenzene solution and a 5 mg / ml TM1 chlorobenzene solution were prepared. The TM1 solution was doped into the PVK solution at 1% VOL and mixed thoroughly by shaking. The hole transport layer (HTL) solution was spin-coated on the HIL film at a speed of 4000 rpm / min for 30 s, heated in air at 140 °C for 30 min, and after returning to room temperature, the film at the electrodes required for testing was wiped off to form a hole transport layer on the surface of the hole injection layer.

[0132] (3) The film obtained in (2) was transferred to a glove box filled with inert gas, and the luminescent layer quantum dot (QD) n-octane solution was spin-coated on it at a speed of 2000 rpm / min for 30 s, and heated in a nitrogen atmosphere at 100 °C for 5 min to form a luminescent layer on the surface of the hole transport layer.

[0133] (4) For the film obtained in (3), the electron transport layer (ETL) Zn 0.85 Mg 0.15 O solution was spin-coated at a speed of 2000 rpm / min for 30 s, heated in a nitrogen atmosphere at 85 °C for 30 min, and after returning to room temperature, the film at the electrodes required for testing was wiped off to form an electron transport layer on the surface of the luminescent layer.

[0134] (5) The spin-coated ITO substrate obtained in (4) was placed on a mask plate and sent into a vacuum evaporation chamber. At a vacuum degree lower than 6×10 -4 Pa, the metal cathode was deposited at a rate of to obtain a QLED device.

[0135] Application Example 2

[0136] In this application example, the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1 above was doped into a PVK solution as a hole transport layer to fabricate a QLED device. The fabrication method was the same as that in Application Example 1, except that in step (2), the TM1 solution was doped into the PVK solution at 5% VOL, and the remaining steps were the same.

[0137] Application Example 3

[0138] In this application example, the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1 above was doped into a PVK solution as a hole transport layer to fabricate a QLED device. The fabrication method was the same as that in Application Example 1, except that in step (2), the TM1 solution was doped into the PVK solution at 10% VOL, and the remaining steps were the same.

[0139] Application Example 4

[0140] In this application example, the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1 above was doped into a PVK solution as a hole transport layer to fabricate a QLED device. The fabrication method was the same as that in Application Example 1, except that in step (2), the TM1 solution was doped into the PVK solution at 15% VOL, and the remaining steps were the same.

[0141] Application Example 5

[0142] In this application example, the hexa-peri-hexabenzocoronene molecule TM1 prepared in Example 1 above was doped into a PVK solution as a hole transport layer to fabricate a QLED device. The fabrication method was the same as that in Application Example 1, except that in step (2), the TM1 solution was doped into the PVK solution at 20% VOL, and the remaining steps were the same.

[0143] Application Example 6

[0144] For the QLED device in this application example, the fabrication method was the same as that in Application Example 1, except that in step (2), T was not doped into the PVK solution, and the remaining steps were the same.

[0145] The QLED devices prepared in Application Examples 1 - 6 above were used with a Keithley 2400 digital source meter and a silicon photodiode to detect their specific parameters. The detection results are shown in Table 1:

[0146] Table 1 QLED Device Performance

[0147]

[0148] Combining the above table with Figure 9 the current density - voltage - luminance graphs with different doping ratios and Figure 10 the external quantum efficiency - luminance graph, it can be obtained that the maximum luminance of the QLED device prepared by doping with TM1 in the present invention is 12135 cd / m 2, the maximum external quantum efficiency is 11.66%, the maximum current efficiency (CEmax) is 4.00 cd / A, the maximum power efficiency is 1.89 lm / W, and the peak of the electroluminescence spectrum is at 456 nm.

[0149] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A hexabenzocoronet molecule, characterized in that: The structural formula of the hexabenzocorone molecule is as follows: In the above structural formula, R1 and R2 are the same or different groups; R1 and R2 are any of the following groups: Wherein, R is a long straight chain alkyl group or a long straight chain alkoxy group with a chain length of C1-C20.

2. The method for synthesizing hexabenzocorone molecules according to claim 1, characterized in that: When R1 and R2 are the same substituents, the synthesis of the hexabenzocoronet molecule comprises the following steps: (1) mixing iodobenzene or iodobenzene derivatives with a catalyst in a triethylamine solvent, deoxygenating the reaction system, and adding phenylacetylene or phenylacetylene derivatives dropwise under the protection of an inert gas. After the addition is complete, the mixture is reacted at room temperature for 10-15 hours. After the reaction is complete, the mixture is washed with saturated brine, extracted with dichloromethane, and evaporated under reduced pressure to remove the solvent. The crude product is separated and purified by silica gel column chromatography to obtain a first intermediate; (2) mixing the first intermediate and the catalyst dicobalt octacarbonyl in a 1,4-dioxane solvent, reacting at 100-130° C. for 8-16 hours under the protection of an inert gas, and after the reaction is complete, evaporating the solvent under reduced pressure, and separating and purifying the crude product by silica gel column chromatography to obtain a second intermediate; (3) Under the protection of inert gas, the second intermediate is used as the raw material, anhydrous dichloromethane is used as the solvent and bubbled for 1 hour, and then a nitromethane solution of ferric chloride is added and stirred for reaction for 4-6 hours. After the reaction is complete, it is quenched with icy methanol, and the icy methanol is precipitated by filtration and chromatographed on a silica gel column to obtain the third intermediate, i.e., a hexabenzocorone molecule.

3. The method for synthesizing hexabenzocorone molecules according to claim 1, characterized in that: When R1 and R2 are different substituents, the synthesis of the hexabenzocorone molecule comprises the following steps: (1) Under the protection of inert gas, diphenylethylene or diphenylethylene derivative and 1,3-diphenylacetone or 1,3-diphenylacetone derivative in a molar ratio of 1:1 are used as raw materials, ethanol is used as solvent, and after heating under reflux, an ethanol solution of potassium hydroxide is added, and the reaction is carried out at 90-110° C. for 0.1-0.5 h. After the reaction is completed, the fourth intermediate is obtained by filtering and washing; (2) Under the protection of inert gas, the fourth intermediate and p-bromophenylacetylene in a molar ratio of 1:1.5 are used as raw materials, diphenyl ether is used as solvent, the reaction is carried out at 200-280° C. for 18-30 hours, and the fifth intermediate is obtained by post-treatment and silica gel column chromatography; (3) Under the protection of inert gas, the fifth intermediate is used as the raw material and anhydrous dichloromethane is used as the solvent. After bubbling at room temperature for 1 hour, a nitromethane solution of ferric chloride is added, and the reaction is carried out at room temperature for 4-6 hours. Ice methanol is added to quench, the precipitate is filtered, washed with ice methanol, and subjected to silica gel column chromatography to obtain the sixth intermediate; (4) Under the protection of inert gas, the sixth intermediate and boronic acid or boronic acid derivative in a molar ratio of 1:(2-4) are used as raw materials, water and tetrahydrofuran are used as solvents, tetrakistriphenylphosphine palladium is used as a catalyst, potassium carbonate is used as a base, and the reaction is carried out at 60-80° C. for 12-52 hours, washed with saturated brine, extracted with dichloromethane, and evaporated under reduced pressure to remove the solvent. The seventh intermediate, i.e., a hexabenzocorone molecule, is obtained by silica gel column chromatography.

4. The method for synthesizing hexabenzocorone molecules according to claim 2, characterized in that: The molar ratio of iodobenzene or iodobenzene derivative to phenylacetylene or phenylacetylene derivative is 1:(1-1.5), the iodobenzene derivative and the phenylacetylene derivative both contain an R1 group or an R2 group, and the R1 group or the R2 group is not a hydrogen group; The R1 group or the R2 group on the iodobenzene derivative and the phenylacetylene derivative is located at the 4th position on the iodobenzene and the 4th position on the phenylacetylene.

5. The method for synthesizing hexabenzocorone molecules according to claim 2, characterized in that: In step (1), the catalyst is cuprous iodide and bistriphenylphosphine palladium dichloride, the mass volume ratio of iodobenzene or iodobenzene derivative to triethylamine is 1g:30-100ml, and the molar ratio of iodobenzene or iodobenzene derivative to cuprous iodide and bistriphenylphosphine palladium dichloride is 1:(0.02-0.1):(0.02-0.1); In step (2), the mass volume ratio of the first intermediate to 1,4-dioxane is 1 g:(20 ml-100 ml), and the molar ratio of the first intermediate to dicobalt octacarbonyl is 1:(0.05-0.1); In step (3), the mass volume ratio of the second intermediate to anhydrous dichloromethane is 1g:(20ml-100ml), and the molar ratio of the second intermediate to ferric chloride is 1:(10-30).

6. The method for synthesizing hexabenzocorone molecules according to claim 3, characterized in that: The diphenylethylenedione derivative and the 1,3-diphenylacetone derivative both contain an R1 group, and the R1 group is not a hydrogen group; The R1 group on the diphenylethylene derivative and the 1,3-diphenylacetone derivative is located at the 4th position of the benzene ring on the diphenylethylene derivative and the 4th position of the benzene ring on the 1,3-diphenylacetone.

7. The method for synthesizing hexabenzocorone molecules according to claim 3, characterized in that: The boronic acid derivative comprises an R2 group, and the R2 group is not a hydrogen group.

8. The method for synthesizing hexabenzocorone molecules according to claim 3, characterized in that: In step (1), the mass volume ratio of diphenylethylene or diphenylethylene derivative to ethanol is 1 g:10-50 ml, and the molar ratio of potassium hydroxide to diphenylethylene or diphenylethylene derivative is (0.05-0.1):1; In step (2), the mass volume ratio of the fourth intermediate to diphenyl ether is 1 g: 10-50 ml; In step (3), the mass volume ratio of the fifth intermediate to anhydrous dichloromethane is 1 g: (30-100) ml, and the molar ratio of ferric chloride to the fifth intermediate is (10-30): 1; In step (4), the mass volume ratio of the sixth intermediate to the solvent is 1 g: (30-100) ml, the molar ratio of the sixth intermediate to the catalyst is 1: (0.05-0.2), and the molar ratio of the sixth intermediate to potassium carbonate is 1: (5-20).

9. The use of a hexabenzocoronet molecule in an electro-induced device according to claim 1, characterized in that: The hexabenzocoronet molecules are applied in the functional layer of an electro-induced device.

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